The first example of a direct Cu +– [formula omitted] bond. Synthesis and crystal structure of two closely related copper(I) hexafluorosilicate π-complexes with 1-allylbenzotriazole of [Cu 2(C 6H 4N 3(C 3H 5)) 2(H 2O) 2SiF 6]·2H 2O and [Cu 2(C 6H 4N 3(C 3H 5)) 2(CH 3OH) 2(H 2O) 2]SiF 6 composition

Abstract

[Cu 2(C 6H 4N 3(C 3H 5)) 2(H 2O) 2SiF 6]·2H 2O ( I) and [Cu 2(C 6H 4N 3(C 3H 5)) 2(CH 3OH) 2(H 2O) 2]SiF 6 ( II) π-compounds were obtained by alternating current electrochemical synthesis, starting from ethanol–methanol solution containing 1-allylbenzotriazole, H 2SiF 6, CuSiF 6·4H 2O and copper wire electrodes. Both compounds were X-ray structurally investigated. In complex I a mid-point of the C C bond of one 1-allylbenzotriazole (L) molecule, the nitrogen atom from another L moiety, the oxygen atom from a water molecule and the fluorine atom from a SiF 6 2 - anion form the trigonal-pyramidal environment of the Cu I center. One more water molecule is fixed in the crystal space by strong O–H⋯F and O–H⋯O hydrogen bonds. The bridging function of the L, Cu + and SiF 6 2 - units results in a formation of infinite metal-organic layers. The metal surrounding in II differs from that in I by a presence of oxygen atom from the methanol molecule instead of fluorine atom from the SiF 6 2 - anion. An appearance of ⋯ SiF 6 2 - –CH 3OH–Cu +–L–Cu +–H 2O⋯ infinite layers in II instead of ⋯ SiF 6 2 - –Cu +–L–Cu +⋯ in I leads to a noticeable elongation of the unit cell of II along [0 1 0] direction in comparison with I. The structure I represents the first known example of the Cu +– SiF 6 2 - bond.