Synthesis of and Structural Studies on Lead(II) Cysteamin Complexes

Abstract

The novel compounds PbCl(2).(SCH(2)CH(2)NH(3)) (1), Pb(SCH(2)CH(2)NH(2))(2).2PbCl(SCH(2)CH(2)NH(2)) (2), and Pb(SCH(2)CH(2)NH(2))(2) (3) were synthesized by reaction of PbO or PbCl(2) with [HSCH(2)CH(2)NH(3)]Cl and NaOH, and were characterized by elemental analysis, IR-, and UV/vis-spectroscopy. Single-crystal X-ray diffraction revealed different coordination modes for the two Pb atoms in 2. The Pb atom in the Pb(SCH(2)CH(2)NH(2))(2) unit forms two covalent Pb-S and two intramolecular dative Pb...N bonds, leading to a pseudo trigonal bipyramidal configuration with a stereochemically active lone pair. The Pb atom in the PbCl(SCH(2)CH(2)NH(2)) unit, the first moiety structurally characterized of the PbCl(SR) type (R = organic group), forms covalent Pb-Cl and Pb-S bonds, an intramolecular dative Pb...N bond, and two intermolecular Pb...S contacts, giving a pseudo octahedral configuration with a stereochemically active lone pair as well. Despite the Pb(SCH(2)CH(2)NH(2))(2) moiety exhibiting C(2) symmetry in 2, and C(1) symmetry in 3, its structural parameters are rather similar in the two compounds. The influence of the Pb...N bond on molecular structure and thermodynamic stability were estimated by means of quantum chemical ab initio methods. Although an analysis of the wave function in terms of natural bond orbitals (NBO) revealed that n(N) and n(p)(S) compete for the empty p-orbital of the Pb(II) atom, the sigma-type n(N)-6p(Pb) interaction is stronger than the pi-type n(p)(S)-6p(Pb) interaction and hence determines the conformation of the compounds.

Electrochemical syntheses and structures of lead(II) and bismuth(III) complexes of 4-(trimethylammonio)benzenethiolate

“…A large number of zwitterionic ammonium thiolate complexes of transition metals have been reported [1][2][3][4][5][6][7][8][9][10][11], while those with main group metals such as Pb or Bi are limited in number [12][13][14][15]. Metal zwitterionic ammonium thiolates can be prepared by various methods such as proton transfer reaction [1a,4,7,8,16a,16b,16c], precursor reaction [16a,16b], ligand exchange reaction [15], oxidation-reduction reaction [1b] and solid-state reaction [16d].…”

Cost efficient preparation of lead aminoalkoxides directly from lead(II) oxide

“…The reflux condensate was run through molecular sieves before rejoining the reaction mixture to prevent the water from hydrolyzing the product. Preparation of related 2-aminoethanethiolate complexes was recently reported to use a similar route; however, the stronger Pb-S linkages are less susceptible to hydrolysis and removal of water was not necessary [19]. The denticity of the aminoalcohols determined their relative reactivities with PbO.…”

Mononuclear zinc(II) and mercury(II) complexes of Schiff bases derived from pyrrolealdehyde and cysteamine containing intramolecular NH⋯S hydrogen bonds

“…angles of 171.7°and 168.5°for 1 and 2, respectively ( Table 3). The mean SÁ Á ÁN contact distances of 3.24 Å (complex 1) and 3.33 Å (complex 2), which are shorter than the sum of the van der Waals radii (3.35 Å) [49], are comparable to those of other complexes with hydrogen-bond interactions [21,23,24,26,32,[50][51][52]. With the av.…”