Structural trends in a series of bulky dialkylbiarylphosphane complexes of CuI.

CuI com­plexes containing the bulky di­alkyl­biaryl­phosphane 2-(di-tert-butyl­phosphan­yl)-2′,4′,6′-triiso­propyl­biphenyl (tBuXPhos, L) and an ancillary ligand (Cl−, Br−, I−, MeCN, ClO4− or SCN−) have been structurally characterized, namely, chlorido­[2-(di-tert-butyl­phosphan­yl)-2′,4′,6′-triiso­propyl­biphenyl-κP]cop­per(I), [CuCl(C29H45P)], 1, bromido­[2-(di-tert-butyl­phosphan­yl)-2′,4′,6′-triiso­propyl­biphenyl-κP]copper(I), [CuBr(C29H45P)], 2, [2-(di-tert-butyl­phosphan­yl)-2′,4′,6′-triiso­propyl­biphenyl-κP]iodido­copper(I), [CuI(C29H45P)], 3, (aceto­nitrile-κN)[2-(di-tert-butyl­phosphan­yl)-2′,4′,6′-triiso­propyl­biphenyl-κP]copper(I) hexa­fluor­ido­phosphate, [Cu(CH3CN)(C29H45P)]PF6, 4, [2-(di-tert-butyl­phosphan­yl)-2′,4′,6′-triiso­propyl­biphenyl-κP](perchlorato-κO)copper(I), [Cu(ClO4)(C29H45P)], 5, and di-μ-thio­cyanato-κ2S:N;κ2N:S-bis­{[2-(di-tert-butyl­phosphan­yl)-2′,4′,6′-tri­iso­­propyl­biphenyl-κP]copper(I)}, [Cu2(NCS)2(C29H45P)2], 6. Iodide com­plex 3 shows significant CuI–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 CuI centre. When replacing iodide with an aceto­nitrile (in 4) or perchlorate (in 5) ligand, the reduced inter­action between the CuI atom and the ancillary ligand results in stronger CuI–arene inter­actions. No CuI–arene inter­actions are observed in dimer 6, due to the tricoordinated CuI centre having sufficient electron density from the coordinated ligands.