Unusual Polynuclear Copper(II) Complexes with a Schiff-Base Ligand Containing Pyridyl and 1,2,4-Triazolyl Rings

• Published in: Journal of cluster science Vol. 30; no. 5; pp. 1267 - 1275
• Main Authors: Bazhina, Evgeniya S., Bovkunova, Anna A., Medved’ko, Alexey V., Efimov, Nikolay N., Kiskin, Mikhail A., Eremenko, Igor L.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2019; Springer Nature B.V
• Subjects: Antiferromagnetism; Catalysis; Chemistry; Chemistry and Materials Science; Coordination polymers; Copper; Crystal growth; Diffusion rate; Ethanol; Fourier transforms; Imines; Inorganic Chemistry; Ligands; Magnetic properties; Methanol; Mineral oils; Nanochemistry; Nitrogen; Original Paper; Physical Chemistry; Single crystals; Triazoles; 4-Amino-4; X-ray diffraction; Schiff base ligands; 1,2,4-triazole derivatives; Copper(II) complexes; Magnetic properties
• ISSN: 1040-7278; 1572-8862
• DOI: 10.1007/s10876-019-01575-y

The reaction between Cu(NO 3 ) 2 and Schiff-base ligand 4-(pyridin-2-yl)methyleneamino-1,2,4-triazole (L) in water due to hydrolysis process results in the formation of new ligand 4-[bis(pyridin-2-yl-methanol)]amino-1,2,4-triazole (H 2 L 1 ) and 4-amino-4 H -1,2,4-triazole (L 2 ). Slow diffusion of methanol or ethanol vapors into the reaction solution leads to the growth of single crystals of the 12-nuclear complex [Cu 12 (L 1 ) 4 (L 2 ) 6 (NO 3 ) 6 (MeOH) 2 (H 2 O) 6 ](NO 3 ) 10 ·3MeOH·11H 2 O ( 1 ) with an unusual cyclic metal core or 1D coordination polymer {[Cu 3 L 1 (L 2 ) 2 (NO 3 ) 2 (H 2 O) 2 ](NO 3 ) 2 ·1.5H 2 O} n ( 2 ), respectively. According to the X-ray diffraction data, both structures are constructed from similarly formed units, where three copper atoms are linked by one [L 1 ] 2− ligand and two amino-1,2,4-triazolyl fragments. Magnetic behaviour of compound 2 indicates the presence of antiferromagnetic-type exchange coupling between Cu II ions in the trinuclear unit {Cu1–Cu2–Cu3} ( J 12  = − 149 cm −1 , J 23  = –175 cm −1 , zJ  = − 0.7 cm −1 ).