Cobalt phosphonates based on 4-(ethoxycarbonyl)naphthalen-1-yl)phosphonic acid.
The first examples of metal phosphonates based on 4-(ethoxycarbonyl)naphthanen-1-yl)phosphonic acid (4-cnppH2) are reported, namely, Co(4-cnpp) (1), Co2(4-cnpp)2(dptz) (2) and Co2(4-cnpp)2(4,4'-bpy)(H2O) (3) (dptz = 3,6-di(pyridin-3-yl)-1,2,4,5-tetrazine, 4,4'-bpy = 4,4'-bipyridine). The cobalt atoms are four-coordinated with distorted tetrahedral geometries in both 1 and 2, while five-coordinated with a distorted trigonal bipyramidal environment in compound 3. Compound 1 shows a layer structure in which the inorganic layers made up of edge-sharing {CoNO3} dimers and {PO3C} linkages are separated by the organic groups of the 4-cnpp(2-) ligands. Compound 2 displays a different type of layer structure, where the ladder-like chains composed of corner-sharing {CoNO3} and {PO3C} tetrahedra are connected by dptz ligands with the organic groups of the 4-cnpp(2-) ligands pendent on the two sides of the layer. In 3, similar ladder-like chains of corner-sharing {CoNO4} and {PO3C} are also found except that the cobalt atoms within the chain are further bridged by a coordinated water molecule. The chains are cross-linked by 4,4'-bpy, leading to a three-dimensional open-framework structure. Magnetic studies reveal that dominant antiferromagnetic interactions are mediated between the Co(II) ions in all three cases.
State Key Laboratory of Coordination Chemistry, Coordination Chemistry Institute, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China. lmzheng@nju.edu.cn.
Tao
T
Zheng
Song-Song
SS
Bao
Min
M
Ren
Li-Min
LM
Zheng