Coinage metal complexes with N'NN' and SeNSe ligands - Pincer vs bridging coordination pattern

摘要

The reactions of the ligands 2,6-(Me2NCH2)2C5H3N (N'NN') (1) and 2,6-(PhSeCH2)2C5H3N (SeNSe) (4) with different coinage metal starting materials gave 1:1,2:1 or 1:2 metal-to-ligand species, i.e. [Ag(N'NN'){0(0)CCF3}] (2), [{Ag(PPh3)}2(N'NN')](OTf)2 (3), [Au(SeN-Se)Cl]Cl2 (5), [Ag(PPh3)(SeNSe)](OTf) (6), [Cu(MeCN)(SeNSe)](PF6) (7) or [Cu(SeNSe)2](PF6) (8). The new compounds were investigated by IR, multinuclear NMR spectroscopies as well as mass spectrometry. In most cases, the ligands 1 and 4 act as pincer ligands. An attempt to grow single crystals of 2 gave an unexpected result. The crystal investigated by X-ray diffraction proved to be a polynuclear species, [Ag4(N'NN'){O(O)CCF3}4(EtOH)]_n (2a), which contains an unusual, bimetallic triconnective coordination pattern of the N'NN' ligand. Two tetranuclear [Ag4(N'NN'){O(O)CCF3}4(EtOH)] units form centrosymmetric dimers further associated into a polymer which contains four different coordination environments around silver atoms. The complex 3, in which the ligand also exhibits a bimetallic triconnective pattern, shows an intense, long-lived luminescence in the solid state with emission energies in the green region of the visible spectrum.