A Platinum(II) Organometallic Building Block for the Design of Emissive Copper(I) and Silver(I) Coordination Polymers

The tritopic organometallic ligand trans-MeSC6H4C equivalent to CPt-(PMe3)(2)(C equivalent to N) (L1) was prepared from cis-PtCl2(PMe3)(2) and p-ethynyl(methyl thioether)benzene. Its versatility was shown with the formation of [CuX(L1)](n) coordination polymers (CPs) with CuX salts in MeCN (X = I (CP1), CN (CP2), SCN (CP3)). These CPs were characterized by X-ray crystallography, thermal gravimetric analysis (TGA), and IR and Raman spectroscopy. CP1 consists of a 1D head-to-tail chain formed by tricoordinated -C equivalent to N-CuI(eta(2)-C equivalent to C)- linkages, whereas CP2 is built upon a central (CuCN)(n) zigzag chain bearing dangling L1s held by -C equivalent to N-Cu bonds. Finally, CP3 exhibits 2D sheets secured by Cu-N equivalent to C-/-(Me)S-Cu bondings and transversal Cu-S-C equivalent to N-Cu bridges. Concurrently, the CPs formed with AgX (X = NO3-(CP4 and CP5), CF3CO2-(CP6) PF6- (CP7)) exhibits 2D sheets with guest molecules (anion, solvents) inside the tight pores or between layers. These new materials are emissive: L1 (lambda(0-0) similar to 465 nm), CP1-CP7 (500 < lambda(max) < 620 nm). Their photophysical properties (absorption and emission spectra, emission lifetimes (similar to 0.2 < tau(e) < 120 mu s), and quantum yields in the solid state at 77 and 298 K) were analyzed. The various natures of the emissive excited states were addressed by density functional theory (DFT) and time-dependent DFT (TDDFT) computations. For CP1, this state is a triplet halide or pseudohalide to ligand charge transfer (XLCT)-X-3 (CT = charge transfer; X = I; L = L1) and for CP2, it is (XLCT)-X-3 (X = CN; L = L1). However, for CP3, it is (XLCT)-X-3 (X = SCN; L = L1). For CP4, the T-1 state is described as a [MeSC6H4(eta(2)-C equivalent to C)-Ag(NO3)](2)->[Pt]/C equivalent to CC6H4SMe CT.