Coordination complexes of copper(II) with herbicide-trichlorophenoxyacetate: Syntheses, characterization, single crystal X-ray structure and packing analyses of monomeric [Cu(γ-pic)3(2,4,5-trichlorophenoxyacetate)]·H2O, [trans-Cu(en)2(2,4,5-trichlorophenoxyacetate)2]·2H2O and dimeric [Cu2(H2tea)2(2,4,5-trichlorophenoxyacetate)2]·2(H2O)

Three novel coordination complexes of copper(II) with 2,4,5-trichlorophenoxyacetate [Cu(γ-pic)3(L)2]·H2O 1, [trans-Cu(en)2(L)2]·2H2O 2 and [Cu2(H2tea)2(L)2]·2H2O 3, where L = 2,4,5-trichlorophenoxyacetate, γ-pic = γ-picoline, en = ethylenediamine, H2tea = monodeprotonated triethanolamine, were synthesized by addition of γ-picoline/ethylenediamine/triethanolamine, respectively, to the hydrated Cu(2,4,5-trichlorophenoxyacetate)2 suspended in methanol-water (4:1, v/v). The newly synthesized complexes have been characterized by elemental analyses, spectroscopic techniques (UV–Vis and FT-IR), magnetic moment determination, molar conductance studies, TGA and single crystal X-ray diffraction method. The structure determination revealed neutral nature of complexes in all the three cases, with different coordination geometry around the copper(II) metal centre depending upon nature of the N- or N,O-donor ligands. Hydrogen bonding network i.e. O–H⋯O and C–H⋯O in complexes 1, 3 and N–H⋯O, and O–H⋯O in complex 2 stabilizes crystal lattice in copper(II) complexes besides other non-covalent interactions.