Structural Diversity and Rare η¹ Cu–C Interactions in Cu^I Complexes of 1,2,3-Triazole-Functionalized Bisphosphines

Abstract

This manuscript describes the synthesis of copper complexes of 1,2,3-triazolyl-phosphines: o-Ph 2 P(C 6 H 4 ){1,2,3-The reactions of L1−L3 with Cu I salts afforded dimeric complexes having the general formula [Cu 2 (μ -X) 2 L 2 ] (L = L1, X = Cl, Br and I: 1 -3; L= L2, X = Cl, Br and I: 4-6; L = L3; X = Cl, Br, and I: 7−9). The reaction of L4 with CuI in a 1:2 molar ratio afforded 1D-coordination polymer [{(CuI) 2 {o-Ph 2 P(C 6 H 4 ){1,2,3- (10). The reaction of L5 with cuprous halides (CuX) (X = Br, I) yielded mononuclear complexes [CuX{(3,5-Ph 2 PC 6 H 4 -o) 2 1,2,3-N 3 CCH}-κ 2 P,P] (X = Br, 12; I, 13). Crystal structures of complexes 12 and 13 showed close interactions between Cu I and the triazole C7 carbon. These relatively short Cu•••C7 separations may be due to the η 1 −C interaction (d π −p π bond) between the triazolic carbon atom (via p z orbital) and Cu I or three-centered two-electron interaction between Cu I and the triazolic C−H bond. The existence of the Cu•••C interaction was further evinced by the QTAIM analysis in compounds 12 and 13.