1-(2,6-dimethylphenyl)-5-allylsulfanyl-1H-tetrazole and its copper(I) tetrafluoroborate n,σ-complex: synthesis, structure and quantum-chemical calculations

Abstract

1-(2,6-Dimethylphenyl)-5-allylsulfanyl-1 H -tetrazole ( o-dmphast ) and its copper(I) tetrafluoroborate p,σ-complex [Cu 2 ( o-dmphast ) 2 (BF 4 ) 2 ] ( 1 ) were synthesized and X-ray structurally studied. o-Dmphast was prepared in several stages by known protocol, starting from 2,6-dimethyl aniline. The single crystals of 1 were obtained by means of the alternating-current electrochemical technique. The collected diffraction data were processed using CrysAlis RED program. The structures were solved by ShelXT program and refined by least squares method on F 2 by ShelXL program with the following graphical user interface of OLEX 2 . Compound 1 crystallizes in the centrosymmetric space group : a = 7.405(3)), b = 7.786(3), c = 11.625(4) Å, a = 101.90(3) , β = 100.88(3) , g = 104.81(3) , V = 613.0(4) Å 3 , Z = 2. π-Complexe crystallizes in the centrosymmetric space group P 2 1 /n .: a = 9.271(3), b = 14.171(4), c = 11.956(4) Å, β = 91.52(3) , V = 1570.2(9) Å 3 , Z = 2. Allylsulfanyl group of o-dmphast has synclinal conformation relative to the S1—C3 bond and antisynclinal conformation relative to the C2—C3 bond (the corresponding torsion angles C5—S1—C3—C2 and S1—C3—C2—C1 are 76.5(2) and –118.0(3)). In the structure of o-dmphast , the hydrogen atom of the one methyl group (C13) and the hydrogen atom of the methylene group of the allyl substituent form weak С−H···N hydrogen bonds with the nitrogen atoms of the tetrazole ring of neighboring molecules. Tetrazole rings of the nearest molecules are involved in the π···π-stacking interaction at a distance of 3.44 Å. Structure of 1 is built of centrosymmetric dimers which are formed by coordination to two Cu + ions of two chelate-bridging molecules o-dmphast . The dimeric moieties contain a six-membered {Cu 2 N 4 } ring comprised of two pairs of [ - N - N - ] tetrazole fragments. π-Coordinated Cu(I) cation adopts a close to a trigonal pyramidal coordination environment (2N, (C=C) + F). The corresponding four-coordinate geometry indexes τ 4 is 0.78. Copper(I) ion and allylic group (C1, C2 and С3 atoms) in 1 are disordered over two sites with an occupancy ratio of 0.522(4):0.478(4). Fluorine atoms of the anion are also disordered over two sites with an occupancy ratio of 0.737(3):0.263(3). To further analyse the intermolecular interactions in the structures of o-dmphast , Hirshfeld surface analysis and energy framework computational analysis have been performed. Keywords: copper(I), π-complex, allyl derivative of tetrazole, crystal structure, quantum-chemical calculations.