Reactivity Studies of (Phenylethynyl)germylene LGeCCPh (L = HC[C(Me)N-2,6‑iPr2C6H3]2) toward Pentafluorophenylcopper(I), -silver(I), and -gold(I) Complexes

Reactions of (phenylethynyl)­germylene LGeCCPh (L = HC­[C­(Me)­N-2,6-iPr2C6H3]2) with 0.25 equiv of (CuC6F5)4, 1 equiv of AgC6F5·MeCN, and 1 equiv of AuC6F5·SC4H8, respectively, yielded LGe­(CCPh)­CuC6F5 (1), [(LGeCCPh)2Ag]+[Ag­(C6F5)2]− (2), and LGe­(CCPh)­AuC6F5 (3). Complexes 1–3 were characterized by IR and NMR spectroscopy and X-ray crystallography. Compound 1 shows a bonding pattern of the CuC6F5 entity by both the phenylethynyl CC linkage and the L ligand backbone of the γ-C atom, while 3 exhibits a bonding mode of the AuC6F5 entity at the germylene center. Compound 2 is an ionic derivative featuring the Ge–Ag donor–acceptor bond formed under redistribution of the AgC6F5 entity. Further reactions of 1 with (CuC6F5)4, AgC6F5·MeCN, and AuC6F5·SC4H8 afforded the complexes LGe­(CCPh)­(CuC6F5)­(MC6F5) (M = Cu (4), Ag (5), Au (6)). Compounds 4–6 were characterized by IR and NMR spectroscopy, and 5 and 6 were further investigated by X-ray crystallography. Compounds 4–6 all show an additional bonding of the respective MC6F5 moiety at the germylene center of 1. These studies reveal a multiple donor reactivity of LGeCCPh. The slightly different Lewis acidic properties of the congeneric pentafluorophenylcopper­(I), -silver­(I), and -gold­(I) complexes as acceptors are thus disclosed.