The first example of a direct Cu+–SiF62- bond. Synthesis and crystal structure of two closely related copper(I) hexafluorosilicate π-complexes with 1-allylbenzotriazole of [Cu2(C6H4N3(C3H5))2(H2O)2SiF6]·2H2O and [Cu2(C6H4N3(C3H5))2(CH3OH)2(H2O)2]SiF6 comp

[Cu2(C6H4N3(C3H5))2(H2O)2SiF6]·2H2O (I) and [Cu2(C6H4N3(C3H5))2(CH3OH)2(H2O)2]SiF6 (II) π-compounds were obtained by alternating current electrochemical synthesis, starting from ethanol–methanol solution containing 1-allylbenzotriazole, H2SiF6, CuSiF6·4H2O and copper wire electrodes. Both compounds were X-ray structurally investigated. In complex I a mid-point of the CC 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 SiF62- anion form the trigonal-pyramidal environment of the CuI 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 SiF62- 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 SiF62- anion. An appearance of ⋯SiF62-–CH3OH–Cu+–L–Cu+–H2O⋯ infinite layers in II instead of ⋯SiF62-–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+–SiF62- bond.

Graphical abstractI and II π-compounds were obtained by alternating current electrochemical synthesis. Compound I represents the first known example of the Cu+–SiF62- bond. Strongly related I and II compounds crystallize in the same P21/a space group with similar unit cells parameters.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► CuI ion in I is bound to the CC-bond, N (ligand), O (H2O) and F (SiF62-) atoms. ► It is the first observed Cu+–SiF62- bond. ► In structure II O (CH3OH) atom replaces F one in the copper environment. ► ⋯Cu–FSiF52-–Cu–L–Cu⋯ (I) and ⋯SiF62-–H2O–Cu–L–Cu⋯ (II) layers appear.