1,3,5-TRIAMINO-1,3,5-TRIDEOXY-CIS-INOSITOL, A NEW LIGAND WITH A REMARKABLE VERSATILITY FOR METAL-IONS .4. PREPARATION, CHARACTERIZATION, AND X-RAY STRUCTURE OF THE TRINUCLEAR LEAD(II) AND BISMUTH(III) COMPLEXES

Three compounds, containing the complexes [Pb3(H-3taci)]3+ and [Bi3(H- 3taci)2]3+ (taci = 1,3,5-triamino-1,3,5-trideoxy-cis-inositol), have b een prepared by combining solutions of taci and the corresponding meta l nitrates. Single-crystal X-ray analysis of Pb6(H-3taci)2(NO3)5(OH)(H 2O)2, P1BAR, Z = 2, a = 11.1 15(2) angstrom, b = 11.538(3) angstrom, c = 14.182(3) angstrom, alpha = 107.75(2)-degrees, beta = 91.26(2)-degr ees, gamma = 104.23(2)-degrees, and Bi3(H-3taci)2Cl3.6H2O, R3, Z = 3, a = 8.114(1) angstrom, c = 35.960(7) angstrom, revealed the presence o f trinuclear complexes, where each metal ion is bound to one terminal amino group and to two deprotonated, bridging hydroxyl groups of taci. The three metal ions and the three coordinated alkoxo groups of taci form a puckered, six-membered ring with a chair conformation. Rather s hort M-O and M-N bonds and small angles O-M-O and O-M-N were observed within the M3(H-3taci) fragments. In the case of the Pb complex, two [ Pb3(H-3taci)]3+ entities were linked together by a nitrato ligand. All six Pb(II) atoms are coordinated to this bridging nitrate. The coordi nation number of Pb is 4. In the Bi(III) complex, two taci ligands sur round the three metal ions in a sandwich type structure. Two additiona l Cl atoms are only weakly bound to Bi. The coordination number of Bi is 6 + 2. The complexes are stable in aqueous solution and were charac terized by NMR spectroscopy and FAB+ mass spectrometry. NMR data (D2O) are in agreement with the highest possible symmetry C3upsilon for the Pb(II) complex and D3h for the Bi(III) complex. In the FAB+ mass spec tra (glycerol matrix), the most intense peaks were assigned to [Pb3(ta ci)(glycerol) - 5H]+ and [Bi3(taci)2 - 8H]+.