Preparation and crystal structure of a non-symmetrical vanadium(II) dimer: tri-μ2-bromido-(hydrogen-tris(3-isopropyl-4-bromopyrazol-1-yl)borato-κ3N,N′,N′′)-tris(tetrahydrofuran-κO)divanadium(II) – tetrahydrofuran (1/1), C34H57BBr6N6O4V2

Peter J. Bonitatibus; William H. Armstrong; Guido J. Reiss

doi:10.1515/ncrs-2020-0187

Open Access Published by De Gruyter (O) June 2, 2020

Preparation and crystal structure of a non-symmetrical vanadium(II) dimer: tri-μ₂-bromido-(hydrogen-tris(3-isopropyl-4-bromopyrazol-1-yl)borato-κ³N,N′,N′′)-tris(tetrahydrofuran-κO)divanadium(II) – tetrahydrofuran (1/1), C₃₄H₅₇BBr₆N₆O₄V₂

Peter J. Bonitatibus , William H. Armstrong and Guido J. Reiss

From the journal Zeitschrift für Kristallographie - New Crystal Structures

https://doi.org/10.1515/ncrs-2020-0187

Abstract

C₃₄H₅₇BBr₆N₆O₄V₂, orthorhombic, Pna2₁ (no. 33), a = 17.198(2) Å, b = 12.9497(11) Å, c = 20.496(2) Å, V = 4564.8(9) Å³, Z = 4, R_gt(F) = 0.0441, wR_ref(F²) = 0.1093, T = 183(2) K.

CCDC no.: 2003156

The molecular complex is shown in the figure (a solvent molecule THF is omitted for clarity). Table 1 contains crystallographic data and Table 2 contains the list of the atoms including atomic coordinates and displacement parameters.

Table 1:

Data collection and handling.

Crystal:	Blue-purple block
Size:	0.50 × 0.40 × 0.30 mm
Wavelength:	Mo Kα radiation (0.71073 Å)
μ:	5.70 mm⁻¹
Diffractometer, scan mode:	Siemens P4, ω
θ_max, completeness:	27.0°, >99%
N(hkl)_measured, N(hkl)_unique, R_int:	26077, 7061, 0.105
Criterion for I_obs, N(hkl)_gt:	I_obs > 2 σ(I_obs), 6504
N(param)_refined:	479
Programs:	Bruker [1], [2], SHELX [3], [4], [5], [6], Diamond [7]

Table 2:

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²).

Atom	x	y	z	U_iso*/U_eq
Br1	0.86460(6)	0.16724(7)	0.44095(5)	0.0387(2)
Br2	0.63321(6)	0.42389(8)	0.81703(6)	0.0419(3)
Br3	0.82244(8)	0.90157(8)	0.51603(6)	0.0485(3)
Br4	0.99507(4)	0.34002(6)	0.71747(4)	0.02219(18)
Br5	1.07067(4)	0.53126(7)	0.60144(4)	0.02406(18)
Br6	0.97152(4)	0.62195(6)	0.75027(4)	0.02303(18)
V1	0.93188(7)	0.49787(10)	0.65309(7)	0.0177(3)
V2	1.08962(7)	0.49834(10)	0.72741(7)	0.0188(3)
O1	1.1077(4)	0.4606(5)	0.8296(3)	0.0268(13)
O2	1.1921(3)	0.4101(5)	0.7066(3)	0.0281(14)
O3	1.1674(3)	0.6253(5)	0.7385(3)	0.0295(14)
O4	1.3732(10)	0.6166(16)	0.8491(11)	0.138(7)
N1	0.8193(4)	0.4152(5)	0.5518(4)	0.0223(14)
N2	0.8944(4)	0.3983(5)	0.5733(4)	0.0217(14)
N3	0.7559(4)	0.4778(5)	0.6547(4)	0.0237(15)
N4	0.8179(4)	0.4707(5)	0.6966(4)	0.0201(14)
N5	0.8069(4)	0.6058(6)	0.5735(4)	0.0258(16)
N6	0.8791(4)	0.6271(5)	0.5993(4)	0.0223(14)
C1	0.7999(5)	0.3454(7)	0.5058(5)	0.0258(18)
H1B	0.752995	0.341886	0.483390	0.031*
C2	0.8621(5)	0.2807(7)	0.4981(4)	0.0267(18)
C3	0.9208(5)	0.3159(7)	0.5399(4)	0.0229(17)
C4	1.0040(5)	0.2789(7)	0.5479(5)	0.0257(18)
H4	1.027935	0.320149	0.582617	0.031*
C5	1.0501(6)	0.2978(10)	0.4856(6)	0.043(3)
H5C	1.102514	0.274126	0.491340	0.065*
H5B	1.026357	0.260962	0.450142	0.065*
H5A	1.050379	0.370382	0.475920	0.065*
C6	1.0073(6)	0.1653(8)	0.5691(6)	0.040(2)
H6C	1.060526	0.144395	0.573737	0.059*
H6B	0.980903	0.157340	0.610061	0.059*
H6A	0.982394	0.123171	0.536695	0.059*
C7	0.6899(5)	0.4623(7)	0.6871(5)	0.0259(19)
H7	0.640310	0.462990	0.669042	0.031*
C8	0.7074(4)	0.4451(7)	0.7518(5)	0.0263(18)
C9	0.7888(4)	0.4518(6)	0.7573(4)	0.0207(16)
C10	0.8380(5)	0.4366(7)	0.8169(4)	0.0244(17)
H10	0.892281	0.444606	0.803257	0.029*
C11	0.8227(6)	0.5175(8)	0.8690(5)	0.035(2)
H11C	0.855530	0.504525	0.905996	0.053*
H11B	0.833840	0.584855	0.851746	0.053*
H11A	0.769233	0.514311	0.882155	0.053*
C12	0.8297(6)	0.3282(8)	0.8444(6)	0.040(2)
H12C	0.861970	0.321306	0.882395	0.059*
H12B	0.776472	0.316045	0.856083	0.059*
H12A	0.845582	0.278807	0.812109	0.059*
C13	0.7806(6)	0.6910(7)	0.5432(5)	0.031(2)
H13	0.733301	0.696073	0.521497	0.038*
C14	0.8326(6)	0.7676(7)	0.5491(5)	0.0301(19)
C15	0.8950(5)	0.7245(6)	0.5851(4)	0.0252(18)
C16	0.9706(5)	0.7758(7)	0.6057(5)	0.0278(18)
H16	1.000305	0.724176	0.630177	0.033*
C17	0.9577(6)	0.8683(8)	0.6517(6)	0.039(2)
H17C	1.007066	0.897825	0.663190	0.059*
H17B	0.926508	0.919364	0.630089	0.059*
H17A	0.931623	0.845371	0.690473	0.059*
C18	1.0206(6)	0.8076(9)	0.5472(6)	0.042(2)
H18C	1.067608	0.839521	0.562507	0.062*
H18B	1.033379	0.747583	0.521874	0.062*
H18A	0.992326	0.855650	0.520604	0.062*
C19	1.0664(8)	0.5041(9)	0.8853(5)	0.048(3)
H19B	1.017725	0.534375	0.870979	0.058*
H19A	1.097532	0.558098	0.905236	0.058*
C20	1.0512(10)	0.4228(9)	0.9328(7)	0.061(4)
H20B	0.997296	0.424086	0.946835	0.073*
H20A	1.084426	0.430280	0.970761	0.073*
C21	1.0693(8)	0.3239(9)	0.8965(6)	0.051(3)
H21B	1.023503	0.297042	0.874770	0.061*
H21A	1.089818	0.271644	0.925722	0.061*
C22	1.1303(7)	0.3586(8)	0.8475(6)	0.041(2)
H22B	1.181677	0.358657	0.867101	0.049*
H22A	1.130777	0.313535	0.809737	0.049*
C23	1.1981(6)	0.3279(9)	0.6597(7)	0.053(3)
H23B	1.179797	0.350626	0.617324	0.063*
H23A	1.167452	0.268935	0.673407	0.063*
C24	1.2825(7)	0.3003(12)	0.6567(9)	0.067(4)
H24B	1.291877	0.235273	0.678849	0.080*
H24A	1.299394	0.293918	0.611770	0.080*
C25	1.3238(7)	0.3830(10)	0.6889(8)	0.057(4)
H25B	1.338493	0.436034	0.657802	0.069*
H25A	1.370253	0.357206	0.710104	0.069*
C26	1.2674(7)	0.4249(13)	0.7382(9)	0.075(5)
H26B	1.270321	0.386770	0.778819	0.090*
H26A	1.277113	0.497393	0.746773	0.090*
C27	1.2014(10)	0.6824(13)	0.6860(7)	0.074(5)
H27B	1.161297	0.710110	0.657615	0.089*
H27A	1.235443	0.638621	0.660366	0.089*
C28	1.2461(8)	0.7673(9)	0.7171(8)	0.058(3)
H28B	1.298554	0.745412	0.727663	0.069*
H28A	1.248466	0.827501	0.689050	0.069*
C29	1.2015(13)	0.7884(12)	0.7758(9)	0.095(7)
H29B	1.160342	0.837495	0.766638	0.114*
H29A	1.234833	0.816806	0.809473	0.114*
C30	1.1686(6)	0.6888(8)	0.7968(6)	0.038(2)
H30B	1.200835	0.657448	0.830265	0.046*
H30A	1.116523	0.697920	0.813976	0.046*
C31	1.4475(8)	0.5571(15)	0.8389(10)	0.082(5)
H31B	1.451921	0.534908	0.793847	0.098*
H31A	1.492179	0.599568	0.849561	0.098*
H1A	0.717340	0.499680	0.558940	0.098*
C32	1.4434(10)	0.4703(19)	0.8812(11)	0.109(8)
H32B	1.484163	0.473586	0.913844	0.131*
H32A	1.449281	0.406697	0.856673	0.131*
C33	1.3662(10)	0.4742(17)	0.9125(10)	0.094(6)
H33B	1.336337	0.413363	0.900907	0.113*
H33A	1.371970	0.475624	0.959613	0.113*
C34	1.3283(8)	0.5613(15)	0.8919(9)	0.085(6)
H34B	1.315660	0.604038	0.929265	0.102*
H34A	1.279979	0.541848	0.870741	0.102*
B1	0.7678(5)	0.4994(8)	0.5810(5)	0.025(2)

Source of material

Synthesis was carried out by reaction of 0.21 g (0.36 mmol) trans-[VBr₂(THT)₄] (THT = tetrahydrothiophene) [8] with the potassium salt of hydrogen-tris(3-isopropyl-4-bromopyrazol-1-yl)borate (0.11 g, 0.18 mmol) [9] in 15 mL of rigorously anhydrous and deoxygenated tetrahydrofuran. The reaction was stirred overnight at room temperature under N₂ to develop an intense blue-purple solution from which KBr precipitated. Salts were removed by filtration and previously dried Celite aided in salt removal. Concentration and cooling to 0 °C under N₂ led to quality blue-purple crystals of the title complex within 48 h.

Experimental details

The carbon-bound hydrogen atoms were placed using a riding model (AFIX 13/23/33/43) implemented in the SHELXL system using the standard parameters for the constrained U_iso(H) values [5].

The absolute structure determination succeeded as the derived Flack parameter is found to be near zero [−0.03(2) from 1598 selected quotients] using Parsons’s method [5]. The classical calculation of the Flack parameter showed a slightly better result 0.00(1) using all unique reflections [5], [6].

Comment

The asymmetric unit consists of a dinuclear vanadium(II) complex (see the Figure) and one uncoordinated THF solvent molecule. The dinuclear {V^II(μ₂-Br)₃V^II}⁺ core of the title complex is capped by a hydrogen-tris(3-isopropyl-4-bromopyrazol-1-yl)borate ligand on one side and terminally coordinated by tetrahydrofuran molecules on the other. Inspection down the V⋯V axis show pyrazolyl rings bisect the bromides of the {V^II(μ₂-Br)₃V^II}⁺core, with boron sitting unperturbed on the V⋯V axis, i.e., the angle made by B(1)-V(1)-V(2) is 178.3°. A space-filling plot illustrated that steric bulk presented by the three isopropyl groups that point toward the {V^II(μ₂-Br)₃V^II}⁺ core prohibited coordination of a second hydrogen-tris(3-isopropyl-4-bromopyrazol-1-yl)borate ligand.

While a Cambridge Structural Database [10] search shows several examples of dinuclear tri-μ₂-chlorido vanadium(II) complexes [11], [12], [13], [14], [15], [16], [17], [18], [19], dinuclear tri-μ₂-bromido transition metal complexes are rare with only one other structurally characterized example reported to the best of our knowledge [20]. The distances between bromido-bridged vanadium(II) ions at the centers of these cofacial bioctahedra are rather similar, with a V⋯V distance of 3.146(6) Å reported in reference [12] and 3.112(2) Å in the title complex. The average V—Br bond lengths in each of these dinuclear complexes are essentially identical.

References

1. Bruker. SAINT V4.028. Program for reduction of data collected on Bruker CCD Area detector diffractometers. Bruker Analytical X-ray Systems Inc., Madison, WI, USA 1994.Search in Google Scholar

2. Bruker. SMART V4.031. Program for Bruker CCD X-ray diffractometer control. Bruker Analytical X-ray Systems Inc., Madison, WI, USA 1994.Search in Google Scholar

3. Sheldrick, G. M.: Phase annealing in SHELX-90: direct methods for larger structures. Acta Crystallogr. A46 (1990) 467–473.10.1107/S0108767390000277Search in Google Scholar

4. Sheldrick, G. M.: SHELXS-93. Program for the Refinement of Crystal Structures. University of Göttingen, Germany 1993.Search in Google Scholar

5. Sheldrick, G. M.: Crystal structure refinement with SHELXL. Acta Crystallogr. C71 (2015) 3–8.10.1107/S2053229614024218Search in Google Scholar PubMed PubMed Central

6. Parsons, S.; Flack, H. D.; Wagner, T.: Use of intensity quotients and differences in absolute structure refinement. Acta Crystallogr. B69 (2013) 249–259.10.1107/S2052519213010014Search in Google Scholar PubMed PubMed Central

7. Brandenburg, K.: DIAMOND. Visual Crystal Structure Information System. Ver. 4.6.2. Crystal Impact, Bonn, Germany 2020.Search in Google Scholar

8. Sable, D. B.; Armstrong, W. H.: An unusual species containing the mixed-valence {V^III(μ-N)V^IV}⁴⁺ core obtained by reductive decomposition of Me₃SiN₃: [VBr₂(N₃)(dmpe)(μ-N)VBr(dmpe)₂]. Inorg. Chem. 31 (1992) 161–163.10.1021/ic00028a006Search in Google Scholar

9. Trofimenko, S.; Calabrese, J. C.; Domaille, P. J.; Thompson, J. S.: Steric effects in polypyrazolylborate ligands. poly(3-isopropylprazolyl)borates: ligands of intermediate steric requirements. Inorg. Chem. 28 (1989) 1091–1101.10.1021/ic00305a019Search in Google Scholar

10. Groom, C. R.; Allen, F. H.: The Cambridge Structural Database (CSD) in retrospect and prospect. Angew. Chem. Int. Ed. 53 (2014) 662–671.10.1002/anie.201306438Search in Google Scholar PubMed

11. Raimondi, A. C.; Hasegawa, T.; Nunes, F. S.: N,N,N′,N′-Tetramethylethane-1,2-diaminium tri-μ-chloro-bis[(N,N,N′,N′-tetramethylethane-1,2-diamine)vanadium(II)] tetraphenylborate tetrahydrofuran solvate. Acta Crystallogr. E60 (2004) m1010–m1012. CSD Entry: BEVMAR.10.1107/S1600536804015004Search in Google Scholar

12. Cotton, F. A.; Duraj, S. A.; Extine, M. W.; Lewis, G. E.; Roth, W. J.; Schmulbach, C. D.; Schwotzer, W.: Structural studies of the vanadium (II) and vanadium(III) chloride tetrahydrofuran solvates. Chem. Commun. 23 (1983) 1377–1378. CSD Entry: CANZUM.10.1039/c39830001377Search in Google Scholar

13. Cotton, F. A.; Duraj, S. A.; Roth, W. J.: Two compounds containing the tris(μ-chloro)hexakis(tetrahydrofuran)divanadium(II) cation. Preparation, structures, and spectroscopic characterization. Inorg. Chem. 24 (1985) 913–917. CSD Entry: DAGPAC.10.1021/ic00200a023Search in Google Scholar

14. Cotton, F. A.; Duraj, S. A.; Manzer, L. E.; Roth, W. J.: Mononuclear and binuclear cationic complexes of vanadium(II). J. Am. Chem. Soc. 107 (1985), 3850–3855. CSD Entries: DATBEF, DATBIJ, DATBOP.10.1021/ja00299a016Search in Google Scholar

15. Canich, J. A. M.; Cotton, F. A.; Duraj, S. A.; Roth, W. J.: Preparation and structures of the binuclear vanadium(II) complexes [L₃V(μ-Cl)₃VL₃]BPh₄ (L = tetrahydrofuran or 3-methyltetrahydrofuran). Polyhedron 6 (1987) 1433–1437. CSD Entry: FUGLUO.10.1016/S0277-5387(00)80906-7Search in Google Scholar

16. Calderazzo, F.; De Benedetto, G. E.; Pampaloni, G.; Mossmer, C. M.; Strahle, J.; Wurst, K.: Bis(arene)vanadium(0) complexes as a source of vanadium(II) derivatives by both disproportionation of the [V(η⁶-arene)₂]⁺ cations and oxidation. of [V(η⁶-arene)₂]. J. Organomet. Chem. 451 (1993) 73–81. CSD Entries: LANRAT, LANREX.10.1016/0022-328X(93)83010-SSearch in Google Scholar

17. Kataoka, Y.; Makihira, I.; Yamagata, T.; Tan, K.: Stabilizing Effect of HMPA (Hexamethylphosphoric Triamide) on Vanadium–Carbon Bonds and Their Application to Carbon–Carbon Bond Formation Reactions. Organometallics 16 (1997) 4788–4795. CSD Entry: NOXRAT.10.1021/om970545aSearch in Google Scholar

18. Pampaloni, G.; Englert, U.: Tetrahydrofuran and 1,2-dimethoxyethane derivatives of vanadium(II) and vanadium(III). Inorg. Chim. Acta 231 (1995) 167–173. CSD Entry: ZAXTUN.10.1016/0020-1693(94)04438-2Search in Google Scholar

19. Bonitatibus, P. J.: Experimental Crystal Structure Determination. CSD Commun. 2020. CCDC 1996863 (YUJYUA). DOI: 10.5517/ccdc.csd.cc250wy1.Search in Google Scholar

20. Canich, J. A. M.; Cotton, F. A.; Roth, W. J.: Binuclear cationic μ-bromo complexes of vanadium(II). Polyhedron 7 (1988) 737–740. CSD Entry: VIJZET.10.1016/S0277-5387(88)80047-0Search in Google Scholar

Received: 2020-04-17

Accepted: 2020-05-11

Published Online: 2020-06-02

Published in Print: 2020-08-26

This work is licensed under the Creative Commons Attribution 4.0 International License.