Substituent-dependent coordination modes of 1-methyl-5-R-tetrazoles in their cupric chloride complexes.

Graphical abstract A strong effect of C5-substituent on coordination modes of 1-methyl-5-R-tetrazoles and structural motifs of their copper(II) chloride complexes was observed. Abstract A series of cupric chloride complexes with 1-methyl-5-R-tetrazole ligands, where R = NH 2 , t -Bu, Ph, MeS, CH CH 2 , MeSO 2 , were synthesized by interaction of CuCl 2 ·2H 2 O with the above ligands LNH 2 , LtBu, LPh, LMeS, LVin, and LMeSO 2 , respectively. The obtained complexes [Cu(LNH 2 ) 3 Cl 2 ]·H 2 O (1), [Cu(LtBu) 2 Cl 2 ] (2), [Cu(LPh) 2 Cl 2 ] (3), [Cu(LMeS) 2 Cl 2 ] (4), [Cu(LVin)Cl 2 ] n (5), and [Cu(LMeSO 2 )(H 2 O)Cl 2 ] n (6) were characterized by single crystal X-ray analysis. The effect of C5-substituent on coordination modes of tetrazole ligands and structural motifs of complexes was observed. Complexes 1 – 4 are mononuclear, with the tetrazole ring N4 coordination. Complex 5 presents 1D coordination polymer, formed at the expense of triple bridge between two neighboring copper(II) cations (double chlorido bridge and the tetrazole ring N3,N4-bridge). In 6 , being also 1D coordination polymer, coordination chains are composed of alternating Cu(LMeSO 2 ) 2 and Cu(H 2 O) 2 fragments linked by double chlorido bridges. Ligand LMeSO 2 shows N3 coordination, being rare among 1,5-disubstituted tetrazoles. The influence of the nature of C5 substituents on coordination features of the obtained complexes is discussed by using quantum-chemical calculations of the electronic structure and basicity of the ligands. [ABSTRACT FROM AUTHOR]