Syntheses and crystal structures of novel manganese(II) or cadmium(II) arsonates with dinuclear clusters or 1D arrays.

Hydrothermal reactions of cadmium(II) or manganese(II) salts with aryl arsenic acids RAsO(3)H(2) (R = C(6)H(5)-, H(2)L(1); 3-NO(2)-4-OH-C(6)H(3)-, H(3)L(2)) and 1,10-phenanthroline (phen) led to six new cadmium(II) and manganese(II) organo arsonates, namely, Cd(phen)(HL(1))(2)(H(2)O) (1), M(phen)(H(2)L(2))(2) (M = Mn, 2; Cd, 3), M(phen)(2)(H(2)L(2)) x (H(2)O) (M = Mn, 4; Cd, 5), and Mn(phen)(2)(HL(1)) x (H(2)O) (6). The structures of 1, 4, and 5 contain two types of dinuclear clusters, whereas 2 and 3 exhibit 1D chains based on dinuclear M(2)(mu-O)(2) cluster units further bridged by arsonate ligands. Compound 6 features a 1D helical chain in which neighboring two metal centers are bridged by one arsonate ligand. Magnetic property measurements on compounds 2, 4, and 6 indicate that there exist very weak antiferromagnetic interactions between magnetic centers in all three compounds. Compounds 1-6 display typical ligand-centered fluorescence emission bands.