Bis(benzotriazol-1-yl)methane as a linker in the assembly of new copper(II) coordination polymers: Synthesis, structure and investigations

New copper(II) complexes with bis(benzotriazol-1-yl)methane (1,1′-bbtm) were obtained. The complexation of copper ion leads to selective isolation of 1,1′-bbtm from a mixture of bis(benzotriazolyl)methane isomers. Crystal structures of [Cu(1,1′-bbtm)(NO3)2]n (1), [Cu(1,1′-bbtm)(H2O)(NO3)2]n (1a), [Cu3(1,1′-bbtm)4(H2O)8]A6, where A = ClO4− (2), BF4− (3), and of all three bbtm isomers, were characterized by single-crystal X-ray diffraction. Powder diffraction data of bulky compounds are in a good agreement with single-crystal data for 1–3. The structures consist of neutral chain 1∞[Cu1∞[Cu(1,1′-bbtm)(H2O)(NO3)2] (1a) and 3∞[Cu3∞[Cu (1,1′-bbtm)(NO3)2] framework (1), or positively charged (2, 3) layers 2∞[Cu32∞[Cu3(1,1′-bbtm)4(H2O)8]n6n+ formed through 1,1′-bbtm (in 1–3) and NO3− (in 1) bridges. The 1,1′-bbtm molecules are coordinated to copper(II) ions in a bidentate bridging manner by N(3), N(3′) atoms of a triazole rings. Compounds 1–3 were investigated by static magnetic susceptibility method in the range 2–300 K. An antiferromagnetic exchange between copper(II) ions was found in 1, J = −0.33 cm−1. Compounds 2 and 3 are found to follow the Curie law with magnetic moments almost constant in all the temperature range studied because copper(II) ions are separated by long non-conjugated bridging ligands.

Graphical abstractThree bis(benzotriazolyl)methane (bbtm) isomers and four new copper(II) complexes with 1,1′-bbtm were synthesized and characterized by single-crystal X-ray diffraction. The complexation of copper ion leads to selective isolation of 1,1′-bbtm from a mixture of bbtm isomers. Compounds were investigated by static magnetic susceptibility method.Figure optionsDownload full-size imageDownload as PowerPoint slide