Structural variability and thermally-induced mesomorphisms in complexes of copper(II) with 4-halobenzoates, 2,2'-bipyridine and 4,4'-bis(dodecyl)-2,2'-bipyridine

[Cu-2(4-XC6H4COO)(4)(C2H5OH)(2)] (X = F, Br) reacted with 2,2 '-bipyridine (bpy) to form mononuclear complexes [Cu(4-FC6H4COO)(2) (bpy)(H2O)] (1) and [Cu(4-BrC6H4COO)(2)(bpy)(H2O)]center dot H2O (2), respectively. These complexes formed single crystals. Complex 1 crystallized in the orthorhombic Pccn space group, while 2 crystallized in the triclinic P-1 space group. In addition, [Cu-2(4-XC6H4COO)(4)(C2H5OH)(2)] (X = F, Cl, Br, I) reacted with 4,4'-bis(dodecyl)-2,2'-bipyridine (L) to form mononuclear complexes [Cu(4-FC6H4COO)(2)(L)]center dot H2O (3), [Cu(4-ClC6H4COO)(2)(L)]center dot 1/2H(2)O (4) and [Cu(4-BrC6H4COO)(2)(L)]center dot 1/2H(2)O (5), and a dinuclear complex, [Cu-2(4-IC6H4COO)(4)(L)(2)] (6), respectively. Complex 3 was a semisolid at room temperature, while 4-6 formed single crystals. Complexes 4 and 5 crystallized in the triclinic P-1 space group, while 6 crystallized in the monoclinic P2(1)/c space group. Complexes 4-6 suffered structural changes on heating to form dinuclear thermotropic metallomesogenic complexes. The electronic effect of halogens and linear alkyl chains were studied towards their molecular structures and mesomorphisms.

Automated summary

In this study, various mononuclear and dinuclear complexes were synthesized by reacting different ligands with copper ions, exhibiting diverse characteristics in terms of crystal structures and thermotropic mesomorphic properties.