Structural trends in a series of bulky dialkylbiarylphosphane complexes of Cu I

Cu I complexes containing the bulky dialkylbiarylphosphane 2-(di- tert -butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl ( t BuXPhos, L ) and an ancillary ligand (Cl − , Br − , I − , MeCN, ClO 4 − or SCN − ) have been structurally characterized, namely, chlorido[2-(di- tert -butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κ P ]copper(I), [CuCl(C 29 H 45 P)], 1 , bromido[2-(di- tert -butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κ P ]copper(I), [CuBr(C 29 H 45 P)], 2 , [2-(di- tert -butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κ P ]iodidocopper(I), [CuI(C 29 H 45 P)], 3 , (acetonitrile-κ N )[2-(di- tert -butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κ P ]copper(I) hexafluoridophosphate, [Cu(CH 3 CN)(C 29 H 45 P)]PF 6 , 4 , [2-(di- tert -butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κ P ](perchlorato-κ O )copper(I), [Cu(ClO 4 )(C 29 H 45 P)], 5 , and di-μ-thiocyanato-κ 2 S : N ;κ 2 N : S -bis{[2-(di- tert -butylphosphanyl)-2′,4′,6′-triisopropylbiphenyl-κ P ]copper(I)}, [Cu 2 (NCS) 2 (C 29 H 45 P) 2 ], 6 . Iodide complex 3 shows significant Cu I –arene interactions, in contrast to its chloride 1 and bromide 2 counterparts, which is attributed to the weaker interaction between the iodide ion and the Cu I centre. When replacing iodide with an acetonitrile (in 4 ) or perchlorate (in 5 ) ligand, the reduced interaction between the Cu I atom and the ancillary ligand results in stronger Cu I –arene interactions. No Cu I –arene interactions are observed in dimer 6 , due to the tricoordinated Cu I centre having sufficient electron density from the coordinated ligands.