• Transit. Met. Chem. (IF 1.016) Pub Date : 2020-02-13
Jian Chang, Shu-Zhen Zhang, Ya Wu, Hong-Jia Zhang, Yin-Xia Sun

Abstract Three Ni(II) complexes {[NiL(μ-OAc)(CH3CH2OH)]2Ni} (1), {[NiL(μ-OAc)(CH3OH)]2Ni]·2CH2Cl2·2CH3OH (2) and {[NiL(μ-OAc)(CH3OH)]2Ni}·1.5CH3OH (3) based on a Salamo-type bis-oxime ligand (H2L = 2,2′-[ethylenedioxybis(nitrilo-methylidyne)]dinaphthol) have been synthesized and characterized by physicochemical and spectroscopic methods. The complexes 1, 2 and 3 are all trinuclear structures, and the center Ni(II) ions are six-coordinated and show the slightly distorted octahedral coordination. They all consist of three Ni(II) ions, two deprotonated L2- units, two μ-acetato ligands and two coordinated solvent molecules, as well as the crystallizing solvent molecules. Although the molecular structures of the Ni(II) complexes 1, 2 and 3 are similar to each other, obtained in different solvents, the supramolecular structures are entirely different. The complexes 1, 2 and 3 possess the self-assembled infinite 1D, 3D and 2D supramolecular structures via different intermolecular interactions (hydrogen bonds, C–H···π and π···π stacking interaction), respectively. But complex 2 formed a 3D structures by intramolecular hydrogen bonds. It is significant that the solvent molecules have obvious effects on the optical properties and molecular configuration. The Hirshfeld surface analysis showed that the short-range forces of the hydrogen bonds in complexes 1, 2 and 3 accounted for 67.8%, 44.6% and 52.7%, respectively. The molecular orbital energies for ligand H2L and complex 1 were obtained by DFT calculation, and the electron distribution, energy level and energy gap of HOMO and LUMO were given.

更新日期：2020-02-13
• Transit. Met. Chem. (IF 1.016) Pub Date : 2020-02-06
Bingxue Han, Hao Chen, Yuanyuan Zhao, Yaru Liu, Gang Li

Abstract Recently, crystalline solid materials as proton conductors have attracted intensive attention. Herein, two highly stable complexes, 2D coordination polymer [Cd(3,5-DFPhH2IDC)2]·H2O (1) and supramolecule [Cd(3,5-DFPhH2IDC)2(phen)(H2O)]·0.5H2O (2) (phen = 1,10-phenanthroline), have been synthesized by using 2-(3,5-difluorophenyl)imidazole-4,5-dicarboxylic acid (3,5-DFPhH3IDC) as organic ligand. The water-assisted proton-conductive properties of 1 and 2 were investigated by impedance spectroscopy. Notably, the proton conductivity of both complexes attains the optimized value of 4.90 × 10−5 S cm−1 for 1 and 2.04 × 10−4 S cm−1 for 2 under 100 °C and 98% RH. Consequently, their proton-conducting mechanisms based on the Ea values were highlighted. Graphic abstract

更新日期：2020-02-07
• Transit. Met. Chem. (IF 1.016) Pub Date : 2020-02-01
Zhuo-Ling Chen, Jie Yang, Wei-Wei Cheng, Jing Huang, Di Yang, Yun-Shan Xue, Xiu-Hong Wu

Abstract A novel Cd(II)-based coordination polymer, namely {[Cd3L3(dbp)2]}n (1), was solvothermally prepared based on the rigid ligand 2,6-naphthalenedicarboxylic acid (H2L) and N-donor linker 4,4′-dimethyl-2,2′-bipyridine (dbp). The single-crystal X-ray diffraction analysis shows that compound 1 possesses a fascinating 3D architecture, constructed from a trinuclear secondary building unit [Cd3(COOR)6] and linear L2− linker. The whole structure of compound 1 can be simplified as uninodal 6-connected sxb network with Schlafli symbol of {485,463}. Compound 1 exhibits strong photoluminescent emissions with emission peak at 425 nm. Most strikingly, 1 could be selectively quenched by Cu2+ ion and nitrobenzene (NB) as potential luminescent sensory material. Meanwhile, vapor-phase fluorescence response of 1 toward NB was also investigated.

更新日期：2020-02-03
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-09-19
Adnan S. Abu-Surrah, Abdussalam K. Qaroush

Abstract Transition metal complexes of the general formula [(S∩N∩N∩S)MCl2] (M: Cr(II), 2; Fe(II), 3, Co(II); 4; (S∩N∩N∩S): cis-1,2-N1,N2-bis{(benzo[b]thiophen-2-yl)methylene-diaminocyclohexane, S-DACH, 1) were prepared and characterized. The new complexes have been utilized as catalysts for the coupling reaction of carbon dioxide and the epoxides, styrene oxide (SO), and (±)-propylene oxide (PO), in the presence of bis(triphenylphosphoranylidene)imminium bromide (PPNBr) as a co-catalyst. The reactions were carried out under relatively low pressure and solvent-free conditions. The catalyst systems showed to be selective for the formation of cyclic carbonates. In general, the Cr(II)-based catalyst exhibited the highest activity for the coupling reaction of CO2 with both SO and (±)-PO compared with the corresponding iron(II) and cobalt(II) complexes under similar reaction conditions with turnover numbers values of 2445 and 1164 for the production of propylene carbonate and styrene carbonate, respectively.

更新日期：2020-01-30
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-10-24
Y. Kondratenko, A. A. Zolotarev, I. Ignatyev, V. Ugolkov, T. Kochina

Abstract The interaction of triethanolamine (TEA) with Cu(II) salts of salicylic, cinnamic and succinic acids was studied for the first time. The structure of the synthesized complexes was investigated by single-crystal X-ray diffraction. TEA complexes with Cu(II) salicylate (1) and cinnamate (2) are binuclear mixed ligand complexes, but interaction of TEA with Cu(II) succinate leads to the formation of cationic mononuclear complex—[Cu(TEA)2](C4H4O4) (3). Cu(II) complexes 1–3 were also characterized by physicochemical and spectroscopic methods. Their antimicrobial activity was investigated.

更新日期：2020-01-30
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-08-26
Hui Zhu, Dong Liu, Yue-Hua Li, Guang-Hua Cui

Abstract Two Ag(I) complexes, namely [Ag2(L1)2(HMIP)2·H2O]n (1) and [Ag2(L2)2(HPA)2]n (2) (L1 = 1,6-bis(2-methylbenzimidazol-1-yl)hexane, L2 = 1,6-bis(benzimidazol-1-yl)hexane, H2MIP = 5-methylisophthalic acid, H2PA = phthalic acid), were hydrothermally synthesized and characterized by physicochemical and spectroscopic methods. 1 Processes a binuclear Ag(I) structure which is further extended into a 2D supramolecular network by hydrogen bonds and π–π stacking interactions. 2 Features a 1D meandering chain which is linked into a 3D supramolecular network by Ag···O and π–π stacking interactions. Complex 1 is shown to be a highly sensitive material for luminescence detecting Fe3+ in aqueous solution. These complexes display high photocatalytic activities for degradation of methylene blue under UV irradiation.

更新日期：2020-01-30
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-08-24
Noluthando V. Gamede, Tsitsi A. Kapfunde, Edward Ocansey, Denis M. Ngumbu, James Darkwa, Banothile C. E. Makhubela

Abstract The industrial process of hydroformylation or the oxo process has been used for many years in the production of aldehydes from alkenes. Different metals have been used as efficient catalysts for hydroformylation, in which linear and branched aldehydes are the products obtained; therefore, the development of new catalysts for hydroformylation with high selectivity to aldehydes is important. Rhodium complexes 6–9 were synthesized using [RhCl(CO)2]2, or [RhCl(COD)]2, with either pyrazolylpyridyl N′N′N pincer ligands or a pyrazolylpyridyl N′N ligand. These complexes were then evaluated as catalyst precursors in the hydroformylation reaction using a variety of alkenes. The catalysts all showed activity in hydroformylation but the most active catalyst was methyl-substituted pyrazolyl–rhodium complex 7 following optimization of temperature, syngas pressure and amount of catalyst. Other olefinic substrates were used for hydroformylation in the presence of 7 under the optimum hydroformylation conditions. Undecene and dodecene as substrates only showed minimal formation of aldehydes with predominantly isomerization of the alkene being observed.

更新日期：2020-01-30
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-09-17
Hui-Min Lin, Ling-Hui Wang, Xu-Feng Liu, Xing-Hai Liu, Zhong-Qing Jiang

Abstract In this paper, three diiron butane-2,3-dithiolate complexes [Fe2(CO)5L{µ-SCH(CH3)CH(CH3)S}] [L = P(4-C6H4F)3, 2; P(4-C6H4OCH3)3, 3; P(3-C6H4Cl)3, 4] have been synthesized by CO substitution of the starting complex [Fe2(CO)6{µ-SCH(CH3)CH(CH3)S}] (1) with the corresponding monophosphine coligands in the presence of Me3NO·2H2O as the decarbonylating agent in 61‒74% yields. These complexes have been characterized by elemental analysis, IR, NMR spectroscopy, and single-crystal X-ray diffraction analysis. In addition, electrochemical studies revealed that these complexes can catalyze the reduction of proton to H2 in the presence of acetic acid under the electrochemical conditions.

更新日期：2020-01-30
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-08-28
Longgang Wang, Xuan Zhang, Yanshuai Cui, Xiaolei Guo, Shengfu Chen, Haotian Sun, Dawei Gao, Qinghua Yang, Jianxin Kang

Abstract Noble metal nanoparticles have been drawing great attention for the treatment of water pollutants. The catalytic activity of noble metal nanoparticles is usually reduced due to their aggregation. Amphiphilic molecule micelles have potential to stabilize the noble nanoparticles against aggregation. In this study, a novel facile method was reported for preparing polyethyleneimine-oleic acid (PEI-oleic acid) micelle-stabilized gold nanoparticles (PO-AuNPsn), where the gold nanoparticles (AuNPs) were embedded in the shell area of micelles. When the molar ratio of [N] to [Au] was 50, 100, and 200, the mean diameter of AuNPs was 3.52 ± 0.42, 3.11 ± 0.28, and 2.85 ± 0.48 nm, respectively. The corresponding zeta potential of the PO-AuNPsn was determined to be 26.2, 28.9 and 35.7 mV, respectively. Furthermore, PO-AuNPsn remained stable in aqueous solution at room temperature for more than 1 month. More importantly, PO-AuNPsn had higher catalytic activity for 4-nitrophenol (4-NP) reduction in aqueous solution compared with previous reports, where PO-AuNPs200 showed a Knor value of 9367 s−1 g−1. It is believed that PO-AuNPsn showed high catalytic activity because of their small size, high stability, and the location of AuNPs in the shell area, which made it easier for AuNPs to contact with 4-NP. The method described in this report represents a new method to prepare small and stable noble metal nanoparticles for catalytic applications in the future.

更新日期：2020-01-30
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-10-26
Dongwon Kim, Soojin Lee, Young A. Lee, Ok-Sang Jung

Abstract Self-assembly of CuX2 with C3-symmetric tridentate ligand, 1,3,5-tris(nicotinoyloxy-methyl)benzene (L), affords thermodynamically stable C2-symmetric metallacyclodimers, [Cu2X2L2(H2O)2]X2(H2O)2 (X− = NO3−, BF4−, and ClO4−) in high yields. These cyclodimeric species show the significant anion effects on the catechol oxidation catalysis in chloroform in the order [Cu2(NO3)2L2(H2O)2](NO3)2(H2O)2 > [Cu2(BF4)2L2(H2O)2](BF4)2(H2O)2 > [Cu2(ClO4)2L2(H2O)2](ClO4)2(H2O)2.

更新日期：2020-01-30
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-08-30
Juhyun Cho, Saira Nayab, Jong Hwa Jeong

Abstract A facile synthetic approach has been adopted towards the synthesis of (2R,3R)-N2,N3-bis((S)-1-phenylethyl)butane-2,3-diamine via demetalation of its dichloro Zn(II) complex, which itself was separated from a mixture of diastereomeric Zn(II) complexes by fractional crystallization. The synthesized chiral 1,2-diamine ligand was evaluated as a chiral auxiliary for the Cu(II)-catalysed asymmetric Henry reaction of 3-phenylpropanal and nitromethane, yielding (S)-1-nitro-4-phenylbutan-2-ol in excellent yields (up to 99%) and enantioselectivities (up to 97%). Graphic abstract A facile synthetic approach towards (2R,3R)-N2,N3-bis((S)-1-phenylethyl)butane-2,3-diamine (2b) via fractional crystallization and demetalation of its Zn(II) complex has been adopted. 2b served as a highly enantioselective pro-ligand with Cu(OAc)2 for asymmetric Henry reaction of 3-phenylpropanal and nitromethane in the presence of base with 97% > ee and 99% yield.

更新日期：2020-01-30
• Transit. Met. Chem. (IF 1.016) Pub Date : 2020-01-20
Ashish Kumar Dhara, Kapil Kumar, Sheela Kumari, U. P. Singh, Kaushik Ghosh

Abstract Tridentate ligands having meridional NNO donor centres were designed and synthesized mimicking the copper coordination in the metal site of galactose oxidase enzyme. Mononuclear copper complexes [Cu(L1)Cl] (1) (L1H = (E)-2-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)phenol), [Cu(L2)Cl] (2) (L2H = (E)-4-methyl-2-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)phenol), [Cu(L3)Cl] (3) (L3H = (E)-1-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)naphthalen-2-ol), [Cu(L4)Cl] (4) (L4H = (E)-2-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)phenol), [Cu(L5)Cl] (5) (L5H = (E)-2-((2-phenyl-2-(pyridin-2-yl)hydrazono)methyl)phenol), and [Cu(L6)Cl] (6) (L6H = (E)-2,4-di-tert-butyl-6-(((pyridin-2-ylmethyl)imino)methyl)phenol) were synthesized and characterized. Molecular structure of complex 3 was determined by single crystal X-ray crystallography. Phenoxyl radical complexes were generated in solution via chemical oxidation using ceric ammonium nitrate (CAN), and the radical complexes were characterized by UV–Vis–NIR spectrophotometer. DFT calculations were performed at B3LYP level to optimize the ground-state molecular geometry of the complexes. To understand the electronic properties and absorption spectra of the complexes, TD-DFT calculations were executed for phenoxyl radical complexes considering triplet as well as singlet spin states. Alcohol oxidation was examined utilizing complexes 1–6 as catalyst, and importance of stabilization of Cu(I) intermediate was scrutinized and generation of Cu(II)–OOH was examined. Catalytic promiscuity for catechol oxidase and phenoxazinone synthase activity by complexes (1–5) was investigated. Theoretical calculations and ESI–MS spectral studies were performed during oxidation chemistry of benzyl alcohol, catechol and o-amino phenol to support the proposed mechanism.

更新日期：2020-01-21
• Transit. Met. Chem. (IF 1.016) Pub Date : 2020-01-11
Yingying Wang, Donghui Wang, Weiqing Shu, Jingquan Sha, Haifeng Zhang

Abstract Two cubane-like complexes, namely [Ni4L4(HOEt)4] (1), [Co4L4(HOEt)4] (2) (H2L = (E)-2-((3-hydroxypropylimino)methyl)-6-methoxyphenol), were prepared under solvothermal conditions. Structural analyses show that complexes 1–2 are tetranuclear complexes with a cubane topology in which four M atoms and four µ3-O atoms occupy the alternate vertices of the cubane. The magnetic properties of them have been investigated. Antiferromagnetic interactions were observed for complexes 1 and 2.

更新日期：2020-01-13
• Transit. Met. Chem. (IF 1.016) Pub Date : 2020-01-01
Faith E. Witkos, Jeffrey C. Monroe, Christopher P. Landee, Mark M. Turnbull, Jan L. Wikaira

Abstract Hexakis(3-bromo-2(1H)-pyridone)copper(II) perchlorate was prepared. Crystals and powdered bulk samples were characterized using IR, single-crystal and powder X-ray diffraction, combustion analysis, EPR and temperature-dependent magnetic susceptibility data. The complex crystallizes in the triclinic space group P$$\bar{1}$$ and comprises a Jahn–Teller distorted Cu(II)–O6 coordination sphere with the ligands coordinated via the pyridone O-atoms. EPR and variable temperature susceptibility measurements show that the complex is well isolated magnetically in the lattice.

更新日期：2020-01-01
• Transit. Met. Chem. (IF 1.016) Pub Date : 2020-01-01

Abstract Three macroacyclic Schiff base complexes have been obtained by the reaction of a previously known Schiff base ligand, 2-((Z)-(2-((4-((Z)-2-((Z)-2-hydroxy-3-methoxybenzylideneamino)benzyl)piperazin-1-yl)methyl)phenylimino)methyl)-6-methoxyphenol (H2L), and Mn(II), Zn(II) and Cd(II) ions in mixture of ethanol and methanol solvents. The resultant complexes were characterized by physical and spectroscopic methods. Molar conductivity (ɅM) data were measured at 25 °C using 10−3 M solutions of the complexes in acetonitrile solvent. In addition, the structure of the [MnL]ClO4·CH3CN complex has been revealed by a single-crystal X-ray structural analysis. In this complex, the Mn(II) has been oxidized to Mn(III), with the manganese ion being in a slightly distorted trans-O2N4 octahedral coordination environment arising from all six donor atoms of the doubly deprotonated ligand. The interaction of the ligand and the corresponding Mn(III), Zn(II) and Cd(II) complexes with calf thymus DNA (ct-DNA) has been appraised by dynamic viscosity, emission titration and competitive fluorescence methods which revealed that the compounds interact with ct-DNA via an intercalation mechanism.

更新日期：2020-01-01
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-12-07
Lingling Yang, Dongwon Kim, Soomin Hyun, Young-A Lee, Ok-Sang Jung

Self-assembly of ZnX2 (X− = ClO4− and CF3SO3−) with naphthalene-2,6-diyl-diisonicotinate (L) gives rise to the 2D sheet structures with composition of [ZnL2(H2O)2](ClO4)2·H2O and [ZnL2(CF3SO3)2], respectively. [ZnL2(H2O)2](ClO4)2·H2O is packed in an interpenetration mode, whereas [ZnL2(CF3SO3)2] exists as a simple 2D network in the crystalline solid state. These two crystals have been employed as hetero-catalysts for transesterification reactions of phenylacetate with alcohol. The catalytic effect on the transesterification reaction shows the order of [ZnL2(H2O)2](ClO4)2·H2O > Zn(CF3SO3)2 > [ZnL2(OTf)2] > Zn(ClO4)2, which indicate that molecular packing is an important factor in the catalysis.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-12-07
Xiaozhen Han, Sarah Whitfield, Jacob Cotten

A series of bipyridyl (Bpy) Pd(II) complexes with 3-hydroxyflavone (Fla) [PdBpyFlaR][BF4] (R=OCH3 (1), R=CH3 (2), R=H (3), R=Cl (4)) were prepared and characterized. The molecular structures of the four compounds were determined by UV–Vis, 1H NMR, 13C NMR, COSY, HSQC, HMBC, FTIR, ESI mass spectra and elemental analysis. Their ability to release carbon monoxide was investigated through oxygenation reaction under various conditions of temperature and light irradiation. The nitroxygenation reaction was also studied with nitroxyl, HNO, generated in situ from Angeli’s salt. The experimental results showed that oxygenation reaction of [PdBpyFla]+ with oxygen happens at high temperature (> 80 °C) and light does not affect the reaction, whereas nitroxygenation reaction with HNO happens at room temperature without light irradiation. Carbon monoxide released from the complexes during the nitroxygenation reaction was trapped by deoxymyoglobin.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-12-05
Ran Li, Shanshan Liu, Bing Du, Weili Wu, Bo Li, Liya Wang

Two complexes based on isophthalic acid ligand were successfully synthesized and structurally characterized. Compound 1 exhibits a three-dimensional supramolecular structure. It is assembled from L3− ligands to form a 2D layer with the water ligands orientated above and below each layer. Adjacent layers are connected through hydrogen bonding between carboxylic groups and coordinated, free water molecules to generate a three-dimensional supramolecular structure. The structure of compound 2 consists of tetranuclear cobalt clusters which were linked by the acid ligands to generate a layered structure. Neighboring layers are further connected through bpp ligands to form a three-dimensional structure. The variable-temperature magnetic susceptibility data show that complexes 1 and 2 exhibit antiferromagnetic interactions.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-12-04
Soichiro Kawamorita, Bijak Riyandi Ahadito, Takeshi Naota

The synthesis, structure and photophysical properties of dinuclear bis(phenylpyridine)(salicylaldiminato)Ir(III) complexes bearing polymethylene linkers are described herein. Chiral and achiral dinuclear Ir complexes bearing short (n = 2), medium (n = 5) and long (n = 8) polymethylene linkers were prepared by reacting [Ir(2-phenylpyridinato)IrCl]2 with the corresponding salicylaldimine derivatives. The facial configurations of the coordination sites and the polymethylene-linked structures were unequivocally established based on X-ray crystallography. The emission wavelengths of these polymethylene-linked binuclear complexes in 2-MeTHF in a glassy state at 77 K were found to vary with the length of the linker, such that a hypsochromic shift from yellow to green was observed upon changing from pentamethylene (n = 5) or octamethylene (n = 8) to ethylene (n = 2) linkages. X-ray crystallography and 1H nuclear magnetic resonance analysis combined with density functional theory calculations demonstrated that the present chromism arises from variations in the proximity and conformational rigidity between the two iridium cores, both of which are controlled by the length of the polymethylene linkage.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-12-04
I. Ibrahim, S. O. Idris, I. Abdulkadir, A. D. Onu

The kinetics of redox reaction between N,N′-phenylenebis-(salicylideneiminato)iron(III), hereafter referred to as [FeSalphen]+, and hypophosphorous acid was studied in mixed aqueous medium (DMSO:H2O; 1:4 v/v) under pseudo-first-order conditions at 26 ± 1 °C, µ = 0.2 C2 mol dm−3 (NaCl) and λmax = 435 nm. The reaction was found to be first-order in both reactants second-order overall, acid independent and displayed zero Brønsted–Debye salt effect. Evidence for the presence of free radicals was obtained during the course of the reaction, but none to support the formation of an intermediate complex. In general, the data obtained suggest an outer-sphere mechanism for the reaction. A plausible mechanism is proposed.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-12-02
Yan-Li Gao, Katsuya Inoue

The coordination compound constructed for nitronyl nitroxide radical NIT-Ph-4-Br and CuII(hfac)2(H2O)2 building blocks (NIT-Ph-4-Br = 2-(4-bromo-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, hfac = hexafluoroacetylacetonato) was successfully synthesized. The single-crystal X-ray diffraction analyses indicated that the complexes {(NIT-Ph-4-Br)2[Cu(hfac)2]3} have centrosymmetric five-spin structures consisting of three Cu(II) ions bridged by two nitroxide ligands and that they consist of two types of copper atoms, one with a heavily Jahn–Teller distorted (4 + 2) octahedral coordination (Cuoct) and hfac in trans-positions and the other with square pyramidal five-coordinated (Cupyr) with three hfac oxygen atoms and N–O oxygen atom at the base and the one hfac oxygen atom at the apex. Different geometries of the copper ions are quite important for magnetochemistry. The magnetic susceptibility study of the coordination compound shows strong antiferromagnetic interactions between the metal center and the organic radical.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-11-16
Xian-Lan Hong, Juan Xu, Rong-Hui Jiang, Jie-Ying Li, Jie-Li Chen, Fu-Changsheng Lu

A phenanthrene derivative with a pendant methanol amidogen TFCPIP and its two ruthenium(II) complexes [Ru(phen)2(TFCPIP)](ClO4)2 (1) and [Ru(dmp)2(TFCPIP)](ClO4)2 (2) (phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline, TFCPIP = 2-(2,3,5,6-tetrafluoro-4-aminoethanolphenyl)[4,5-f]-imidazo[1,10]phenanthroline) were synthesized, and the anticancer properties of the two complexes were examined. Both the complexes displayed certain anticancer activities against the selected SGC-7901, BEL-7402, HeLa, A549, MG-63, HepG2, PC-12 and SiHa cancer cells, with the highest cytotoxic activities against SGC-7901. The cell biology experiments for exploring toxicity mechanism with fluorescence imaging technique and flow cytometry demonstrated that the complexes can trigger apoptosis of SGC-7901 cells with an increase in ROS level, a decrease in mitochondrial membrane potential, and effectively inhibit cell invasion and cell growth at G2/M phase, implicating that the complexes induce cellular apoptosis through a ROS-mediated mitochondrial dysfunction pathway.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-11-14
Bo Zhang, Haiying Wang, Xuechao Yan, Yu-Ai Duan, Shuai Guo, Fei-Xian Luo

A series of ruthenium [NNN]- or [NCN]-type complexes (3–7) bearing PPh3 ancillary ligands have been synthesized from pyridine- or phenylene-bridged bis(triazoles) 1 and 2. In the case of [NNN]-pincer complex 3, an unusual and unexpected cis-orientation adopted by two sterically demanding PPh3 ligands was observed, and such configuration proved to be unchanged in solution for a long time. By contrast and as expected, the two phosphines are found to be trans to each other in the case of [NCN]-type pincer complex 4, but an oxidation of RuII center to RuIII occurred. Complex cis-3 underwent ligand exchanges leading to the formations of diphosphine derivatives 5 and 6. As a representative, cis-3 was treated with the base in isopropanol affording a mixture of Ru–hydrido complexes with various phosphine binding modes, one of which (trans-7) bearing two trans-standing phosphines has been successfully isolated and fully characterized. The catalytic performances of all newly synthesized Ru complexes have been examined and compared in transfer hydrogenations of ketones and enones, in which mono-phosphine complexes proved to be significantly superior to their diphosphine counterparts. The catalytic process proved to involve Ru–H key intermediates, but the trans-oriented Ru–H species is unlikely to be the main catalytic contributor. In particular, the best performer cis-3 exhibits high chemoselectivity in certain cases catalyzing α,β-unsaturated ketones, whose behavior is quite different compared to most precedents.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-11-14
Zhi-Qiang Hao, Si-Qi Zong, Xin-Long Yan, Zhi-Hong Ma, Su-Zhen Li, Zhan-Gang Han, Jin Lin

The reactions of pyridine alcohols PyCH2C(R1R2)OH [R1 = H, R2 = 4-BrC6H4 (1); R1 = H, R2 = 4-CF3C6H4 (2); R1 = CH3; R2 = Ph (3)] with Ru3(CO)12 in refluxing toluene gave three mononuclear ruthenium carbonyl complexes [PyCH = C(4-BrC6H4)O]2Ru(CO)2 (4), [PyCH = C(4-CF3C6H4)O][PyCH = C(4-CF3C6H4)]Ru(CO)2 (5), [PyCH = C(4-CF3C6H4)O]2Ru(CO)2 (6) and one dinuclear ruthenium carbonyl complexes [PyCH2C(CH3)(Ph)O]2Ru2(CO)4 (7). Four new complexes 4–7 were characterized by elemental analysis, IR, 1H NMR and 13C NMR spectroscopy. The molecular structures of these complexes were determined by X-ray crystal diffraction analysis.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-11-12
Kunpeng Song, Cheng Tang, Zhijuan Zou, Yundang Wu

The conversion of carbon dioxide into useful chemical raw materials is a necessary development for advancing carbon dioxide capture and storage technology. In this work, a Friedel–Crafts reaction of lignin and metalloporphyrin was used to produce a lignin-based porous organic polymer (P-(L-FeTPP)) with a surface area of up to 1153 m2 g−1. P-(L-FeTPP)) efficiently catalyzed the cycloaddition reactions of epoxides and CO2 under solvent-free conditions, with porphyrin iron acting as an active center. The product yield reached up to 99.6% after 12 h under 1 MPa CO2 and 70 °C. A turnover number of 1481 was achieved, indicating that this catalyst is much more active than its homogeneous counterpart and is one of the most efficient lignin-supported heterogeneous catalysts ever reported. This method for the in situ incorporation of a metalloporphyrin into a lignin skeleton greatly improved the stability of the metal catalyst, and P-(L-FeTPP) was readily recycled and reused more than six times without any significant loss of catalytic activity. Thus, this catalyst design is promising for practical applications, including the industrial production of cyclic carbonates.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-11-02
Cai-Ying Tian, Yan Bi, Jing Chen

Assembly of 3,4-bis(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (L334) and CuBr2 without or with the presence of thiocyanate (SCN−)/dicyanamide [dca, N(CN) 2 − ] anion produces three Cu(II) coordination polymers, {[Cu(L334)(H2O)2](Br)2(CH3OH)}n (1), {[Cu(L334)(SCN)2(H2O)](H2O)(EA)}n (2) (EA = ethyl acetate), and [Cu(L334)(dca)2]n (3). The crystal structures for 1 and 3 show different 2D layered coordination networks, whereas that for 2 represents a distinct 1D coordination pattern. The above results demonstrate that the addition of pseudohalide anions plays an important role in structural construction of coordination architectures. Moreover, 1 exhibits the best adsorption capacity toward methyl orange (MO) dye.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-08-21
Qianqian Zhao, Liuxue Zhang, Xiulian Wang, Xu Jia, Panpan Xu, Meiyan Zhao, Ruikun Dai

Here, we prepared a series of Fe-based metal organic frameworks (MOFs), including MIL-53(Fe), NH2-MIL-53(Fe), MIL-88B(Fe) and NH2-MIL-88B(Fe), via an oil bath process and used them to remove methylene blue under visible light. A comparative study of NH2-MILs and Fe-MILs was conducted. The experimental results showed that the presence of amino groups could improve the adsorption capacities of NH2-MILs, which was attributed to hydrogen bonding interactions and π–π stacking between the amino groups of the dye molecules and the amino-functionalized MOFs. The photocatalytic activities of NH2-MILs under visible light were higher than those of Fe-MILs, owing to the enhancement of visible-light absorption, the decrease in the band gap and the improvement of the adsorption capacity. After several photodegradation experiments, the catalytic activities decreased and could be restored by irradiating the catalysts with ultraviolet light. This study indicated that the amino-functionalized materials had great potential for wastewater treatment and resource utilization.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-08-10
Haiping Yao, Hongwu Tian, Liyao Xu, Yanqing Xia, Li Zhou, Chunli Liu, Tiesheng Shi

Oxidation of 2-furoic hydrazide (FH) by hexachloroiridate(IV) ([IrCl6]2−) was studied kinetically in a wide pH range in aqueous solution of 1.0 M ionic strength. The oxidation reaction followed well-defined second-order kinetics: − d[IrCl62−]/dt = k′[FH]tot[IrCl62−], where [FH]tot denotes the total concentration of FH and k′ stands for the observed second-order rate constants. The established k′–pH profile displays that k′ increases drastically with pH and a plateau region exists between pH 4 and 6. A stoichiometric ratio of Δ[FH]tot/Δ[IrCl62−] = 1/4 was revealed by spectrophotometric titrations. 1H NMR spectroscopic studies indicated that FH was cleanly oxidized to 2-furoic acid. The kinetic data suggest a reaction mechanism in which all the three protolysis species of FH react with [IrCl6]2− in parallel, forming the rate-determining steps. Two stabilized hydrazyl radicals are generated in the rate-determining steps, in which a single electron is transferred to [IrCl6]2−. The two hydrazyl radicals react rapidly in consecutive steps requiring 3 mol of Ir(IV) to form 2-furoic acid as the final product. Rate constants of the rate-determining steps were deduced through a simulation of the rate expression to the k′–pH dependency data. Values of these rate constants demonstrate that the three protolysis species of FH have a huge reactivity span, changing by about 109 times toward reduction in [IrCl6]2− and that FH can be readily oxidized in neutral and basic media. Rapid scan spectra and the measured activation parameters suggest that an outer-sphere electron transfer is probably taking place in each of the rate-determining steps. This is the first kinetic study on the oxidation reactions of FH and provides concurrently the protolysis constants of FH (pKa1 = 3.04 ± 0.08 and pKa2 = 11.6 ± 0.1) at 25.0 °C and 1.0 M ionic strength.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-06-25
Kun Zhao, Yao Qu, Yancong Wu, Cong Wang, Kesheng Shen, Chuang Li, Huilu Wu

1,2-Bis(benzimidazol-2-yl)ethane (bbe) and its transition metal complexes, [Cu(bbe)Cl2]·DMF (1) and [Zn(bbe)Cl2]2(2), have been synthesized and characterized by elemental analysis, UV–Vis and IR spectra. X-ray crystal structure analysis revealed that both complexes have four-coordinate, distorted tetrahedral geometries. Complex 2 has two crystallographically independent but chemically identical Zn(bbe)Cl2 units. The cyclic voltammogram of complex 1 shows an irreversible Cu2+/Cu+ couple. In vitro antioxidant tests showed that complex 1 has significant antioxidant activity against superoxide. Photoluminescence investigations showed that complex 2 exhibits light blue (441 nm) photoluminescence. Compared with the free bbe proligand, a redshift of 16 nm was observed for complex 2, which may be attributed to π*–π transitions.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-09-16
Rongrong Liu, Pingning Jin, Jing-Huo Chen, Guang Yang, Wenhua Zhang

An improved procedure is described herein for the synthesis of triangular Ag(I) 3,5-bis(trifluoromethyl)pyrazolate ({[3,5-(CF3)2Pz]Ag}3), which involves initial preparation of its adducts with triethylammonium nitrate or benzoic acid, namely {[3,5-(CF3)2Pz]Ag}3·(Et3NH·NO3)2 (1) and {[3,5-(CF3)2Pz]Ag}3·(PhCOOH)2 (2), followed by removal of the nitrate and benzoic acid by washing or extraction with water to afford the pristine trisilver complex {[3,5-(CF3)2Pz]Ag}3. X-ray diffraction analysis on 1 and 2 reveals that {[3,5-(CF3)2Pz]Ag}3, acting as a π-acidic host, can combine with guest molecules/ions (NO3−, PhCOOH) by weak Ag–O/C coordination bonds, π–π stacking and C–H···F interactions. Our proposed synthetic procedure for {[3,5-(CF3)2Pz]Ag}3 can be easily carried out at room temperature, without using complex Schlenk techniques or hazardous organic solvents such as benzene and toluene, thus representing a green and facile approach to this well-recognized π-acidic complex.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-06-15
Yihui Jiang, Keke Chai, Tianzhi Han, Wei Zhang, Siyao Chen, Xiaoyu Xu, Linqing Nong, Yuanhua You, Jintao Wang

A ruthenium polypyridine complex, [Ru(mptpy)(Mmptpy)Cl][PF6]2 (Ru1, mptpy = 4-(4-methylphenyl)-2,2′,6′,2″-mptpyridine, Mmptpy = 2-[4-(4-methylphenyl)-2,2′-bipyridin-6-yl]-1-methylpyridinum), was synthesised and characterised. The structure of the complex was determined by single-crystal X-ray crystallography. The ruthenium(II) core has an octahedral coordination environment. The interactions of the complex with DNA were analysed by UV–Vis and fluorescence spectroscopy, revealing a high binding affinity for double-stranded DNA. DNA photocleavage studies monitored by agarose gel electrophoresis showed that the complex cleaved DNA efficiently, whilst mechanistic studies showed that the complex produced reactive oxygen species including singlet oxygen, superoxide anions, and carbon-based radicals that cleave DNA. The complex also showed notable antiproliferation activity towards cancer cells in methyl thiazolyl tetrazolium assays.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-07-15
Yan-Hong Zhang, Gui-Ru Deng, Yuan-Yuan Gao

Three tetranuclear heterometallic coordination compounds of the general formula [(CuL)2M(CuL·CH3OH)](ClO4)2 [(M = Mn(for 2), Co(for 3) and Ni(for 4)] were synthesized by the reaction of the precursor CuL·0.5H2O (1) (H2L = 2,3-dioxo-5,6:13,14-dibenzo-7,12-diphenyl-1,4,8,11-tetraazacyclotetradeca-7,12-diene) with M(ClO4)2·6H2O under solvothermal conditions. The compounds were fully characterized by elemental analysis, FTIR, UV–Vis spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction analysis. In addition, compound 2–4 were studied by magnetic susceptibility measurements. All three heterometallic compounds are isomorphous, and the central ions Mn(II), Co(II) and Ni(II) are connected to three CuL fragments via exo-cis oxamido bridges. Magnetic susceptibility studies of complexes 2–4 indicate the occurrence of antiferromagnetic coupling between the paramagnetic metals. The experimental data have been fitted according to the following Heisenberg Hamiltonian $$\hat{H} = - 2J\hat{S}_{{\text{M}}} (\hat{S}_{{{\text{Cu}}1}} + \hat{S}_{{{\text{Cu}}2}} + \hat{S}_{{{\text{Cu}}3}} )$$, leading to J = − 15.24 cm−1, gCu = 2.06, gMn = 1.96 for complex 2, J = − 22.58 cm−1, gCu = 2.1, gCo = 2.55 for complex 3, and J = − 108.2 cm−1, gCu = 2.09, gNi = 2.27 for complex 4, respectively.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-11-01
Gratien Habarurema, Thomas Gerber, Theonille Mukabagorora, Eric Hosten, Jean Bernard Ndayambaje, Richard Betz

Rhenium(I) and (VII) complexes with cyclohex-1-enylolonium cation and bridging pyridyl derivatives are reported. Additionally, the CO-bridged pyridyl and their related compounds have shown interesting behaviour in their reactivity towards compounds containing two amino groups. The unusual cationic compound: (2,6-diaza-cyclohex-1-enylolonium)2-aza-benzoate (H2den), was isolated from the reaction mixture of 1,2-di(pyridin-2-yl)ethane-1,2-dione with propane-1,3-diamine in methanol. The latter ligand: H2den, was used in the synthesis of rhenium(I) complex in its reaction with [Re(CO)5Cl] that gave rise to novel rhenium(I) complex fac-[Re(CO)3(Hhdm)] (1). The surprising aspect in the formation of (1) is the modification of H2den which was stabilized into a coordinated six-membered pyrimidine ring, 1,4,5,6-tetrahydropyrimidin-2-yl)di(pyridin-2-yl)methanol (H2hdm) chelate. The derived ligand acts as a tridentate monoanionic N2,O-donor ligand towards the fac-[Re(CO)3]+ core. Surprisingly, the 2-aza-benzoate counter-ion that was present in the used ligand is not displayed in the crystal structure of complex 1, and might have been stabilized into 2-aza-benzoic acid (picolinic acid). The reaction of the potential tridentate N2,O-donor ligand 2,2′-dipyridylketone (dpk) with trans-[ReOI2(OEt)(PPh3)2] led to the isolation of [ReO3(dpk·OH)] (2). The ligand H2den and the rhenium complexes were spectroscopically characterized, and the structures of H2den, 1 and 2 were established by X-ray diffraction.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-08-08
Laiming Li, Youxin Li, Aschenaki Assefa, James J. Bao

Platinum was immobilized on magnetic silica gel by means of boronic, nitric, carboxylic or sulfuric acid ligands to give four heterogeneous Pt nano-catalysts, designated as Fe3O4@SiO2-BA@Pt, Fe3O4@SiO2-NA@Pt, Fe3O4@SiO2-CA@Pt and Fe3O4@SiO2-SA@Pt, respectively. Particles of these mono-dispersible Pt catalysts were 10–20 nm in size and could be separated for recycling by means of a magnet. Fe3O4@SiO2-BA@Pt (0.174 mmol/g Pt) showed the best catalytic activity and selectivity, which were better than Speier’s catalyst. Its turnover numbers were up to 1.7 × 106 and 1.1 × 106 for hydrosilylation of 1-hexene or styrene, respectively. This material could also catalyze the hydrosilylation of a broad range of alkenes and alkynes as substrates and methyldichlorosilane or triethoxysilane as silanes. Similar yields of 1-hexyl-methyldichlorosilane at the first and eighth runs (96.5% and 95.2%, respectively), together with a final Pt content of 0.171 mmol/g indicated the outstanding stability of Fe3O4@SiO2-BA@Pt under the catalytic reaction conditions.

更新日期：2019-12-11
• Transit. Met. Chem. (IF 1.016) Pub Date : 2019-07-05
Ramadevi Pulipaka, Soumya R. Dash, Priyanka Khanvilkar, Sarmita S. Jana, Ranjitsinh V. Devkar, Debjani Chakraborty

Mixed ligand Ru(II) phenanthroline complexes of the type [Ru(1,10-phen)2Flq]ClO4 (RPFlq-1-3) and “piano-stool”-type Ru(II) arene complexes [Ru(η6-p-cymene)Cl(Flq)] (RAFlq-1-3), where Flq = fluoroquinolone, have been synthesized, characterized and studied for their anticancer potential. DFT calculations were in line with the proposed structures, wherein the fluoroquinolones are coordinated to the metal through the ring carbonyl and one of the carboxylic oxygen atoms in a bidentate fashion. Binding efficacies of the synthesized complexes with bovine serum albumin (BSA) and CT-DNA were studied spectroscopically, and it has been established that the arene complexes, though have moderate binding propensities to CT-DNA (Kb = 0.8–1.7 × 103 M−1), have 102–103-fold better binding efficacies toward BSA (Ka = 3.2 × 105–2.1 × 106 M−1) due to the presence of the hydrophobic arene moiety. These results further prompted a study in their in vitro cytotoxicity assay on A-549 non-small cell lung cancer and MCF7 breast cancer cell lines. Furthermore, gene expression studies on BAX and BCL-2 genes and FACS analysis confirmed apoptosis as the mode of cell death.

更新日期：2019-12-11
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