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/
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
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].