Jm. Harrowfield et al., LEWIS-BASE ADDUCTS OF LEAD(II) COMPOUNDS .8. SYNTHETIC AND STRUCTURALSTUDIES OF SOME ADDUCTS OF LINEAR POLYAMINES WITH LEAD(II) BROMIDE, Australian Journal of Chemistry, 49(10), 1996, pp. 1043-1050
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.