LEWIS-BASE ADDUCTS OF LEAD(II) COMPOUNDS .8. SYNTHETIC AND STRUCTURALSTUDIES OF SOME ADDUCTS OF LINEAR POLYAMINES WITH LEAD(II) BROMIDE

Syntheses and room-temperature single-crystal X-ray structure determin ations are recorded for adducts of lead(II) bromide with some linear p olyamines. Adducts with ethane-1,2-diamine ('en') and propane-1,2-diam ine ('pn') are of 2:1 and 1:1 stoichiometry respectively. [(en)(2)PbBr 2]((infinity/infinity)) is monoclinic, c 2/c, a 13.076(4), b 7.586(2), c 13.248(4) Angstrom, beta 117.88(2)degrees, Z = 4 f.u.; R was 0.029 for N-o = 1832 'observed' (I > 3 sigma(I)) reflections (a redeterminat ion). [(pn)PbBr2]((infinity/infinity)) is orthorhombic, Pbca, a 23.457 (3), b 9.567(2), c 7.714(3) Angstrom, Z = 8; R 0.051 for N-o 1297. [(e n)(2)PbBr2]((infinity/infinity)) is a single-stranded linear polymer p arallel to c; the lead atom, lying on a crystallographic twofold axis, is six-coordinate PbN4Br2, with the bromine atoms cis in the coordina tion sphere and lying opposed to a bidentate en ligand. The trans site s are linked into a chain by bridging en ligands. [(pn)PbBr2]((infinit y/infinity)) is a more complex two-dimensional polymer; the pn is bide ntate, but the lead atoms are now eight-coordinate with doubly and qua druply bridging bromines linking them into the polymeric sheet. The ad duct with '323tet' (4,7-diazadecane-1,10-diamine) is of a novel (323te t)(2)(PbBr2)(3) stoichiometry, best represented (simplistically) as {[ Pb(323tet)](2)[PbBr6]}((infinity/infinity)) crystals are triclinic, <P (1)over bar>, a 11.892(4), b 9.306(3), c 9.016(6) Angstrom, alpha 60.7 4(4), beta 86.04(4), gamma 74.43(3)degrees, Z = 1 f.u., with R 0.061 f or N-o 2071. About one lead atom type, the ligand is quadridentate, ly ing on one face of the coordination sphere; the region opposite is occ upied by four triply bridging bromine atoms from the [PbBr6] anionic u nits (which contain quasi-octahedral, centrosymmetric lead, with a pai r of trans-bromine atoms terminal and the others bridging) linking the array into a two-dimensional polymer.