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

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for 1:1 adducts of (7R*,14R*)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane ('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) Angstrom, beta 108.39(2)degrees, Z = 4; R 0.051 for N-o 2507. [(tet-b)Pb(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 mononuclear [(tet-b)PbX(2)] entities in which the macrocyclic N-4 ligand occupies one 'face' of the N(4)PbX(2) coordination sphere, the thiocyanate ligands being N-bonded, with Pb-N-C angles of 116(2) and 118(1)degrees; interesting hydrogen-bonding interactions are found, columns of molecules being formed by way of hydrogen bonding between the coordinated (pseudo-)halides and the NH hydrogen atoms which project to the 'rear' face of the ligand of the next molecule, opposite the metal. In contrast 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 0.035 for N-o 3593, is best formulated as [(tet-b)PbBr] Br, one only of the bromide entities being bound to the lead, the other being fully dissociated by hydrogen bonding/ion pairing to the 'rear' side of adjacent ligands, forming hydrogen-bonded sheets rather than columns. This formulation has been extended to provide a description of an analogous mixed chloride-perchlorate 'double salt', [(tet-b)PbCl](ClO4).CH3OH, which 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 [(tet-b)Pb(OClO2O)(2)Pb(tet-b)] (ClO4) Cl.H2O with perchlorate rather than halide coordinated, and an incipiently dimeric cation, as in the parent [(tet-b)Pb(OClO3)](2)(ClO4)(2).2H(2)O.