SYNTHESES AND STRUCTURES OF BISMUTH(III) COMPLEXES WITH NITRILOTRIACETIC ACID, ETHYLENEDIAMINETETRAACETIC ACID, AND DIETHYLENETRIAMINEPENTAACETIC ACID

The reactions of bismuth subcarbonate with nitrilotriacetic acid (NTA) , ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaa cetic acid (DTPA) were used to synthesize the respective bismuth compl exes: (nitrilotriacetato)bismuth(III) dihydrate (1), (hydrogen ethylen ediaminetetraacetato)bismuth(III) dihydrate (2), and bis(guanidinium) (diethylenetriaminepentaacetato)bismuthate(III) tetrahydrate (3). The structures of all three complexes were determined by single-crystal X- ray studies. In 1 the ligand is completely deprotonated, so that the r esulting complex is neutral. The bismuth is eight-coordinate, the coor dination sphere being completed by two water molecules and the 02 and 03' oxygens from an adjacent BI(NTA) molecule. The best description ap pears to be that of a bicapped trigonal prism. In the Bi(HEDTA) comple x, 2, the ligand is singly protonated to give 3-charge. The EDTA ligan d coordinates in a hexadentate fashion involving the two nitrogen atom s and four of the carboxylate oxygen atoms of the EDTA ligand. The Bi atom is eight-coordinate in a bicapped trigonal prism arrangement. The re are no coordinated water molecules. The Bi(DTPA) complex, 3, was is olated as the guanidinium(l+) salt. In 3 the Bi atom is nine-coordinat ed with a monocapped square antiprism arrangement, using the three nit rogens and five oxygen atoms from the DTPA ligand and one 0 from an ad jacent molecule. There are no coordinated water molecules. The BI(DTPA ) is the most soluble of the three complexes. Valence bond sums were c alculated and are given for all three complexes. The antibacterial act ivities of the three complexes 1-3 were determined, and the least solu ble complex, 1, was found to be the most active. Crystallographic data : 1, C6H6NO6Bi.2H(2)O, monoclinic, m,beta=102.49(1)degrees,Z=4;2,C10H1 3N2O8Bi.2H(2)O, monoclinic, ,beta=105.74(1)degrees,Z=4;3,C16H30N9O10Bi .4H(2)O, rom,c=17.091(3)Angstrom,beta=102.72(2)degrees,Z=4.