Structural Diversity and Rare η Cu-C Interactions in Cu Complexes of 1,2,3-Triazole-Functionalized Bisphosphines.

This manuscript describes the synthesis of copper complexes of 1,2,3-triazolyl-phosphines: -PhP(CH){1,2,3-NCCH)C(PPh)} (), (CH){1,2,3-NC(CH(-PPh))-C(PPh)} (), 3-PhP(CHN){1,2,3-NC(CH)C(PPh)} (), -PhP(CH){1,2,3-NC(CHN)C(PPh)} (), and {(3,5-PhPCH-)1,2,3-NCCH} (). The reactions of - with Cu salts afforded dimeric complexes having the general formula [Cu(μ -X)L] (L = , X = Cl, Br and I: - ; L= , X = Cl, Br and I: - ; L = ; X = Cl, Br, and I: -). The reaction of with CuI in a 1:2 molar ratio afforded 1D-coordination polymer [{(CuI){-PhP(CH){1,2,3-NC(CHN)C(PPh)}((-)(-))}}] (). The reaction of with cuprous halides (CuX) (X = Br, I) yielded mononuclear complexes [CuX{(3,5-PhPCH-)1,2,3-NCCH}-κ,] (X = Br, ; I, ). Crystal structures of complexes and showed close interactions between Cu and the triazole C7 carbon. These relatively short Cu···C7 separations may be due to the η-C interaction (- bond) between the triazolic carbon atom ( orbital) and Cu or three-centered two-electron interaction between Cu and the triazolic C-H bond. The existence of the Cu···C interaction was further evinced by the QTAIM analysis in compounds and .