Jm. Harrowfield et al., LEWIS-BASE ADDUCTS OF LEAD(II) COMPOUNDS .10. SYNTHETIC AND STRUCTURAL STUDIES OF SOME 1 1 ADDUCTS OF TET-B WITH LEAD(II) (PSEUDO-)HALIDES/, Australian Journal of Chemistry, 49(10), 1996, pp. 1067-1079
Syntheses and room-temperature single-crystal X-ray structure determin
ations are recorded for 1:1 adducts of 12,14-hexamethyl-1,4,8,11-tetra
azacyclotetradecane ('tet-b') with a variety of lead(II) salts. [(tet-
b)PbCl2] is monoclinic, P2(1)/c, a 7.183(3), b 12.425(2), c 24.418(2)
Angstrom, beta 95.32(3)degrees, Z = 4; conventional R on \F\ was 0.044
for 3188 independent, 'observed' (I > 3 sigma(I)) reflections. [(tet-
b)PbI2] is monoclinic, P2(1)/c: a 19.920(5), b 7.772(5), c 15.605(6) A
ngstrom, beta 108.39(2)degrees, Z = 4; R 0.051 for N-o 2507. [(tet-b)P
b(NCS)(2)] is orthorhombic, P2(1)2(1)2(1), a 36.99(1), b 8.996(5), c 6
.964(3) Angstrom, Z = 4; R 0.043 for N-o 2100. All are discrete mononu
clear [(tet-b)PbX(2)] entities in which the macrocyclic N-4 ligand occ
upies one 'face' of the N(4)PbX(2) coordination sphere, the thiocyanat
e ligands being N-bonded, with Pb-N-C angles of 116(2) and 118(1)degre
es; interesting hydrogen-bonding interactions are found, columns of mo
lecules being formed by way of hydrogen bonding between the coordinate
d (pseudo-)halides and the NH hydrogen atoms which project to the 'rea
r' face of the ligand of the next molecule, opposite the metal. In con
trast to these, the bromide analogue, monoclinic, P2(1), a 9.342(3), b
12.720(5), c 18.845(5) Angstrom, beta 103.17(2)degrees, Z = 4, R 0.03
5 for N-o 3593, is best formulated as [(tet-b)PbBr] Br, one only of th
e bromide entities being bound to the lead, the other being fully diss
ociated by hydrogen bonding/ion pairing to the 'rear' side of adjacent
ligands, forming hydrogen-bonded sheets rather than columns. This for
mulation has been extended to provide a description of an analogous mi
xed chloride-perchlorate 'double salt', [(tet-b)PbCl](ClO4).CH3OH, whi
ch is orthorhombic, P2(1)2(1)2(1), a 19.475(2), b 18.73(1), c 6.820(2)
Angstrom, Z = 4, R 0.054 for N-o 3075. However, another double salt,
modelled in refinement as Pb(tet-b)Cl-0.5(ClO4)(1.5).H2O, orthorhombic
Pnma, a 20.640(5), b 26.16(1), c 8.937(4) Angstrom, Z = 4 dimers, R 0
.074 for N-o 1769, is in this case more appropriately described as [(t
et-b)Pb(OClO2O)(2)Pb(tet-b)] (ClO4) Cl.H2O with perchlorate rather tha
n halide coordinated, and an incipiently dimeric cation, as in the par
ent [(tet-b)Pb(OClO3)](2)(ClO4)(2).2H(2)O.