Three interesting coordination compounds based on metalloligand and alkaline-earth ions: Syntheses, structures, thermal behaviors and magnetic property

Abstract Based on metalloligand L Cu ([Cu(2,4-pydca) 2 ] 2− , 2,4-pydca 2−  = pyridine-2,4-dicarboxylate) and alkaline-earth ions (Ca 2+ , Sr 2+ , and Ba 2+ ), three interesting coordination compounds, [Ca(H 2 O) 7 ][L Cu ·H 2 O]·H 2 O ( 1 ), {Sr[L Cu ·H 2 O]·4H 2 O} n ( 2 ), and {Ba[L Cu ·H 2 O]·8H 2 O} n ( 3 ), have been synthesized and well-characterized by elemental analysis, infrared spectroscopy, thermogravimetric and single-crystal X-ray diffraction analysis. X-ray crystallographic studies reveal that 1 features a discrete 0D coordination compound, while 2 and 3 exhibit the 2D network and 1D chain structures, respectively. Compound 2 is constructed from {L Cu } 2 dimers connected with {Sr 2 } units, which is fabricated by two Sr 2+ ions bridged via two μ 2 -O bridges, while compound 3 is formed by 1D {Ba} n chain linked with metalloligands L Cu and exhibits an interesting sandwich like chain structure. It is noted that the coordination numbers of alkaline-earth ions are in positive correlation with their radiuses. Moreover, the magnetic property of compound 2 has been studied.