β-Diketiminate germylene-supported pentafluorophenylcopper(I) and -silver(I) complexes [LGe(Me)(CuC6F5)n]2 (n = 1, 2), LGe[C(SiMe3)N2]AgC6F5, and {LGe[C(SiMe3)N2](AgC6F5)2}2 (L = HC[C(Me)N-2,6-iPr2C6H3]2): synthesis and structural characterization

Inorg Chem. 2012 Aug 20;51(16):8710-8. doi: 10.1021/ic300216m. Epub 2012 Aug 6.

Abstract

Reactions of LGeMe (L = HC[C(Me)N-2,6-iPr(2)C(6)H(3)](2)) with 0.25 or 0.5 equiv of (CuC(6)F(5))(4) gave the products [LGe(Me)CuC(6)F(5)](2) (1) and [LGe(Me)(CuC(6)F(5))(2)](2) (2), respectively. In situ formed 1 reacted with 0.5 equiv of (CuC(6)F(5))(4) to give 2 on the basis of NMR ((1)H and (19)F) spectral measurements. Conversely, 2 was converted into 1 by treatment with 2 equiv of LGeMe. Reactions of LGeC(SiMe(3))N(2) with 1 or 2 equiv of AgC(6)F(5)·MeCN produced the corresponding compounds LGe[C(SiMe(3))N(2)]AgC(6)F(5) (3) and {LGe[C(SiMe(3))N(2)](AgC(6)F(5))(2)}(2) (4). Similarly, 3 was converted into 4 by treatment with 1 equiv of AgC(6)F(5)·MeCN and 4 converted into 3 by reaction with 2 equiv of LGeC(SiMe(3))N(2). X-ray crystallographic studies showed that 1 contains a rhombically bridged (CuC(6)F(5))(2), while 2 has a chain-structurally aggregated (CuC(6)F(5))(4), both supported by LGeMe. Correspondingly, 3 showed a terminally bound AgC(6)F(5) and 4 a chain-structurally aggregated (AgC(6)F(5))(4), both supported by LGeC(SiMe(3))N(2). Photophysical studies proved that the Ge-Cu metal-metalloid donor-acceptor bonding persists in solutions of 1 and 2 and Ge-Ag donor-acceptor bonding in solutions of 3 and 4 as a result of the clear migration of their emission bands compared to those of the corresponding starting materials. Low-temperature (-50 °C) (19)F NMR spectral measurements detected dissociation of 1, 2, and 4 by the aggregation part of the CuC(6)F(5) or AgC(6)F(5) entities in solution. These results provide good support for pentafluorophenylcopper(I) or -silver(I) species having β-diketiminate germylene as a donor because of its remarkably electronic and steric character.