STUDIES ON THE ANTITUMOR ANTIMONY(III) TRIAMINOCARBOXYLIC COMPLEXONATES - CRYSTAL-STRUCTURES OF NH4[SB(HDTPA)].H2O AND NA[SB(HDTPA)].4(1 2)H2O (DTPA=DIETHYLENETRIAMINEPENTAACETIC ACID)/

The structures of NH4[Sb(Hdtpa)]. H2O(1) and Na[Sb(Hdtpa)]. 4 1/2H(2)O (2) were determined by single-crystal X-ray studies. In both complexes , the Ligand dtpa, which is singly protonated, coordinates in a octade ntate fashion involving the three nitrogen atoms and five of the carbo xylate oxygen atoms of the ligand. The best description appears to be that of a psi-monocapped square antiprism with N(I) being the capping atom and a lone electron pair located on the basal plane of the coordi nation polyhedron. Bond valence sums were calculated and are given for all Sb(II)-dtpa chelates available to date, and preliminary tests for antitumor activity as well as structure-activity relationships: ate a lso presented, Crystallographic data: 1, C14H23N4O10Sb . H2O, monoclin ic, P2(1)/n, a=6.867(1), b=14. 427(1), c=20.049(1) Angstrom, beta=91.8 9(1)degrees, Z=4. A total of 3520 reflections was used in the refineme nt which converged to a final R value of 0.0305; 2, C14H19N3NaO10Sb . 4 1/2 H2O, triclinic, P (1) over bar, a=7.601(1), b=8.576(1), c=17.688 (4) Angstrom, a=99. 11(1), beta= 97.01(1), gamma=97.11(1)degrees, Z=2. A total of 3831 reflections was used in the refinement which converge d to a final R value of 0.0487.