SUPRAMOLECULAR ORGANOLEAD(IV) AND ORGANOTIN(IV) SYSTEMS [(ME3E(IV))3M(III)(CN)6]INFINITY (E = PB OR SN, M = CO OR FE) - COMPARATIVE X-RAY-DIFFRACTION AND SOLID-STATE MULTINUCLEAR MAGNETIC-RESONANCE STUDIES

The synthesis of two novel 3D coordination polymers [(Me3Pb(IV))3M(III)(CN)6]infinity with M = Co (4) and Fe (5) is described together with features of their vibrational spectra. Compound 4 was successfully subjected to a single-crystal X-ray study, the results of which have in turn initiated a reinspection of the structure of the tin homologue, 1, based upon the more appropriate space group P2(1)/c (rather than C2/c). The lattice of 4 corresponds, like that of 1, to a three-dimensional polymeric network. The structure with the space group P2(1)/c (Z = 4) and a = 16.370 (4) angstrom, b = 12.727 (3) angstrom, c = 14.263 (4) angstrom, and beta = 104.69 (2)-degrees was refined to R = 0.060 for 1598 reflections (F(o) > 6-sigma(F(o)). The nonsuperimposable 3D networks of 1 and 4 involve Me3E(NC)2 units (E = Sn or Pb) of trigonal-bipyramidal configuration and remarkably wide, practically parallel channels whose walls are internally coated by constituents of the lipophilic Me3E groups. The presence of three crystallographically nonequivalent chains, [-Co-C = N-E-N = C-]infinity, in the lattices of both 1 and 4 has initiated detailed cross-polarization magic-angle spinning (CP MAS) solid-state NMR studies involving the nuclei C-13, N-15, Co-59, Pb-207, or Sn-119 with a view to establishing structure/NMR correlations. Quite unexpectedly, the CP NMR spectra would favor more symmetrical structures than the X-ray diffraction (XRD) results. The deductions drawn from the NMR spectra in total allow valuable predictions about the structural details of related polymers which are still inaccessible to single-crystal X-ray studies. The delta(Pb-207) values of the tbp-configured Me3Pb(NC)2 units of 4 (78 and 172 ppm) are still more positive than the shift of the tetrahedral reference sample Me4Pb.