Lewis-base adducts of lead(II) compounds .9. Synthetic and structural studies of some 1:1 adducts of 'cyclam' and its hexamethylated derivative 'tet-b' with lead(II) oxoanion salts

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for 1:1 adducts of (1,4,8,11-tetraazacyclotetradecane) ('cyclam') with lead(II) perchlorate and (7R*,14R*)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane ('tet-b') with lead(II) nitrate, perchlorate and acetate ('ac'). [(cyclam)Pb(ClO4)(2)] is orthorhombic, Pb2(1)a, a 16.024(7), b 13.595(4), c 8.6810(5) Angstrom Z = 4 f.u.; R was 0.055 for N-o 1318 independent 'observed' (I > 3 sigma(I)) reflections. [(tet-b)Pb(NO3)(2)](2) is monoclinic, P2(1)/a, a 16.15(2), b 14.550(6), c 19.775(2) Angstrom, beta 90.86(5)degrees: Z = 4 dimers; R 0.074 for N-o 3184. [(tet-b)Pb(ClO4)(2)](2).H2O is monoclinic, P2(1)/c, a 13.663(9), b 9.031(3), c 20.61(1) Angstrom, beta 100.40(3)degrees, Z = 4 f.u.; R.0044 for N-o 2857. [(tet-b)Pb(ac)(2)].2H(2)O is triclinic, <P(1)over bar>, a 13.138(5), b 10.924(4), c 10.518(3) Angstrom, alpha 115.48(3), beta 91.95(2), gamma 102.38(2)degrees, Z = 2 f.u.; R 0.031 for N-o 6485. In all complexes, the macrocycle-N-4 ligand occupies one 'side' of the coordination sphere of the lead atom, with anionic oxygens opposed; the cyclam/perchlorate complex is, like the nitrate, mononuclear with seven-coordinate (N-4)PbO3 with a bidentate O,O'- and a unidentate O-perchlorate. In the tet-b acetate, the anionic oxygen atoms are surprisingly sparse, comprising simply a bidentate acetate in a mononuclear (N-4)PbO2 environment with the other (lattice) acetate bonded to the macrocycle axial NH hydrogens. The nitrate and perchlorate complexes involve bridging anions: in the nitrate, a central centrosymmetric PbO2Pb array is found, the lead atoms being bridged by one oxygen of a bidentate nitrate, the other nitrate being unidentate and the coordination sphere (N-4)PbO4; in the perchlorate, again a centrosymmetric dimer is found, the lead atoms being linked by O,O'-bridging perchlorates (again with (N-4)PbO2 coordination environments), the complex being essentially [(tet-b)Pb(OClO2O)(2)Pb(tet-b)] (ClO4)(2).2H(2)O. The structure of [cyclamH(4)](4+) (NO3-)(4).2H(2)O is also recorded [triclinic, <P(1)over bar>, a 8.626(2), b 8.549(1), c 8.400(2) Angstrom, alpha 80.60(2), beta 76.62(2), gamma 65.06(1)degrees, Z = 1; R 0.044 for N-o 1539], together with that of the diprotonated hexamethyl derivative [tet-bH(2)](2+)(ClO4-)(2).CH3OH [monoclinic, P2(1)/c, a 11.296(3), b 8.834(8), c 26.22(1) Angstrom, beta 99.05(3)degrees, Z = 4 f.u.; R 0.063 for N-o 2583].