LEWIS-BASE ADDUCTS OF LEAD(II) COMPOUNDS .9. SYNTHETIC AND STRUCTURALSTUDIES OF SOME 1 1 ADDUCTS OF CYCLAM AND ITS HEXAMETHYLATED DERIVATIVE TET-B WITH LEAD(II) OXOANION SALTS/

Citation
Jm. Harrowfield et al., LEWIS-BASE ADDUCTS OF LEAD(II) COMPOUNDS .9. SYNTHETIC AND STRUCTURALSTUDIES OF SOME 1 1 ADDUCTS OF CYCLAM AND ITS HEXAMETHYLATED DERIVATIVE TET-B WITH LEAD(II) OXOANION SALTS/, Australian Journal of Chemistry, 49(10), 1996, pp. 1051-1066
Citations number
20
Categorie Soggetti
Chemistry
ISSN journal
00049425
Volume
49
Issue
10
Year of publication
1996
Pages
1051 - 1066
Database
ISI
SICI code
0004-9425(1996)49:10<1051:LAOLC.>2.0.ZU;2-P
Abstract
Syntheses and room-temperature single-crystal X-ray structure determin ations are recorded for 1:1 adducts of (1,4,8,11-tetraazacyclotetradec ane) ('cyclam') with lead(II) perchlorate and 12,14-hexamethyl-1,4,8,1 1-tetraazacyclotetradecane ('tet-b') with lead(II) nitrate, perchlorat e 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. [(t et-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)ov er 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 opp osed; the cyclam/perchlorate complex is, like the nitrate, mononuclear with seven-coordinate (N-4)PbO3 with a bidentate O,O'- and a unidenta te O-perchlorate. In the tet-b acetate, the anionic oxygen atoms are s urprisingly sparse, comprising simply a bidentate acetate in a mononuc lear (N-4)PbO2 environment with the other (lattice) acetate bonded to the macrocycle axial NH hydrogens. The nitrate and perchlorate complex es 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 coordin ation sphere (N-4)PbO4; in the perchlorate, again a centrosymmetric di mer is found, the lead atoms being linked by O,O'-bridging perchlorate s (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 stru cture 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 8 0.60(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 [t et-bH(2)](2+)(ClO4-)(2).CH3OH [monoclinic, P2(1)/c, a 11.296(3), b 8.8 34(8), c 26.22(1) Angstrom, beta 99.05(3)degrees, Z = 4 f.u.; R 0.063 for N-o 2583].