We report an efficient pathway toward sensitization of red room temperature EuIII emission by the charge-transfer (CT) states related to d8-d10 heterometallophilic interactions achieved by the simultaneous application of tetracyanidometallates of PtII/PdII and dicyanidometallates of AuI/AgI in the construction of a trimetallic d-d-f assembly. The combination of Eu3+, [MII(CN)4]2- (M = Pt, Pd), and [MI(CN)2]- (M = Au, Ag) ions along with 4,4'-bipyridine N,N'-dioxide (4,4'-bpdo) results in four novel isostructural 2D {[EuIII(4,4'-bpdo)(H2O)2][MII(CN)4]}·[MI(CN)2]·H2O (MII/MI = Pt/Au, 1; Pt/Ag, 2; Pd/Au, 3; Pd/Ag, 4) coordination networks. They are built of hybrid coordination layers, based on cyanido-bridged {EuIII[MII(CN)4]}n square grids coexisting with metal-organic {EuIII(4,4'-bpdo)}n chains, with the further attachment of [MI(CN)2]- ions through metallophilic {MII-MI} interactions. This results in dinuclear {MIIMI} units generating an orange emissive metal-to-metal-to-ligand charge-transfer (MMLCT) state, whose energy is tuned by the applied d8-d10 metal centers. Thanks to these CT states, 1-4 exhibit room temperature red EuIII photoluminescence enhanced by energy transfer from {MIIMI} units, with the additional role of 4,4'-bpdo also transferring the energy to lanthanides. These donor CT states lying in the visible range successfully broaden the available efficient excitation range up to 500 nm. The overall emission quantum yield ranges from 8(1)% for 4 to 15(2)% for 1, with the intermediate values for 2 and 3 relatively high among the reported EuIII-based compounds with tetracyanido- and dicyanidometallates. We found that the sensitization efficiency is equally high for all compounds because of the similar energies of the CT states, while the main differences are related to the observed emission lifetimes ranging from ca. 80 μs for 4 to 120-130 μs for 2 and 3 to ca. 180 μs for 1. This phenomenon was correlated with the energies of the vibrational states, e.g., cyanide stretching vibrations, responsible for nonradiative deactivation of EuIII excited states, which are the highest for the Pd/Ag pair of 4 and the lowest for the Pt/Au pair in 1. Thus, the heaviest pair of PtII/AuI cyanide metal complexes is proven to be the best candidate for the sensitization of room temperature EuIII luminescence.

中文翻译：

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Tri（III）在三金属氰基桥联配位框架中受d8-d10异嗜金属相互作用控制。

我们报告了通过与d8 / d10的四氰基金属盐和AuI / AgI的二氰基金属盐同时应用而实现的与d8-d10杂金属亲和作用相关的电荷转移（CT）状态，对红色室温EuIII发射致敏的有效途径。三金属ddf组件。Eu3 +，[MII（CN）4] 2-（M = Pt，Pd）和[MI（CN）2]-（M = Au，Ag）离子与4,4'-联吡啶N，N的组合'-dioxide（4,4'-bpdo）产生四个新颖的​​同构2D {[EuIII（4,4'-bpdo）（H2O）2] [MII（CN）4]}·[MI（CN）2]· H2O（MII / MI = Pt / Au，1; Pt / Ag，2; Pd / Au，3; Pd / Ag，4）协调网络。它们由杂化配位层构成，基于与金属有机{EuIII（4,4'-bpdo）} n链共存的氰基桥连的{EuIII [MII（CN）4]} n正方形网格，与[MI（CN）2]-离子通过亲金属的{MII-MI}相互作用进一步附着。这导致双核{MIIMI}单元生成橙色发射金属到金属到配体的电荷转移（MMLCT）状态，其能量由所施加的d8-d10金属中心调节。由于这些CT状态，1-4的室温红色EuIII光致发光通过{MIIMI}单元的能量转移而增强，另外4,4'-bpdo的作用也将能量转移至镧系元素。这些位于可见光范围内的供体CT状态成功地将可用的有效激发范围拓宽至500 nm。总体发射量子产率范围为4的8（1）％到1的15（2）％，其中2和3的中间值在已报道的具有四氰基和二氰基金属化物的EuIII基化合物中相对较高。我们发现，由于CT态的能量相似，所有化合物的敏化效率均相同，而主要区别与所观察到的发射寿命（大约为）有关。大约4到80μs到2和3到120-130μs左右 180μs持续1。这种现象与振动态的能量相关，例如，氰化物拉伸振动，引起EuIII激发态的非辐射失活，Pd / Ag对4最高，Pt最低。 / Au对1。因此，事实证明，最重的PtII / AuI氰化物金属配合物对是室温EuIII发光敏化的最佳候选者。而主要差异与观测到的发射寿命（大约在）之间有关。大约4到80μs到2和3到120-130μs左右 180μs持续1。这种现象与振动态的能量相关，例如，氰化物拉伸振动，引起EuIII激发态的非辐射失活，Pd / Ag对4最高，Pt最低。 / Au对1。因此，事实证明，最重的PtII / AuI氰化物金属配合物对是室温EuIII发光敏化的最佳候选者。而主要差异与观测到的发射寿命（大约在）之间有关。大约4到80μs到2和3到120-130μs左右 180μsfor1。此现象与振动态的能量相关，例如，氰化物拉伸振动，引起EuIII激发态的非辐射失活，Pd / Ag对4最高，Pt最低。 / Au对1。因此，事实证明，最重的PtII / AuI氰化物金属配合物对是室温EuIII发光敏化的最佳候选者。