Syntheses and molecular structures of Co 3+–Na + and Co 3+–K + coordination polymers constructed using mono- and bis-chelated cobalt(III) complexes of bis(2-pyridylcarbonyl)amide ion

Abstract

Four new hetero-bimetallic Co 3+–Na + and Co 3+–K + coordination polymers having the molecular formulae [Na(H 2O)Co( L)(N 3) 3] n ( 1), [Na 2Co( L)(N 3) 3(H 2O) 5][Co( L)(N 3) 3] ( 2), K[Co( L)( NCS) 3]·H 2O ( 3) and K[Co( L) 2][Co( NCS) 4]·0.5H 2O ( 4), were synthesized. Compounds 1–4 were characterized by single crystal X-ray diffraction, IR, UV–Vis, and thermogravimetric methods. These bimetallic systems have EE, EO azide bridge ( 1, 2) as well as bent ( 1, 2, 3) and linear ( 1, 4) aquo bridges. Important features observed among them were: a Z-shaped and diamond-shaped Co 2Na 2 clusters in 1, a centrosymmetric double ladder like polymer based on Na 4 cluster in 2, and a linear KOK core having paddle-wheel structure in 4.