953793-91-4Relevant academic research and scientific papers
New lead(II) complexes with N,S-ligands, including a lead pyrazolonate with unusual packing flexibility
Casas, José S.,Castellano, Eduardo E.,Ellena, Javier,García-Tasende, María S.,Sánchez, Agustín,Sordo, José,Touceda, ángeles,Rodríguez, Saulo Vázquez
, p. 4228 - 4238 (2007)
The reaction of lead(II) acetate in methanol with thiosemicarbazones derived from β-keto esters and β-keto amides (HTSCs) afforded two lead(II) thiosemicarbazonates and numerous homoleptic ([PbL2]) and/or heteroleptic ([Pb(OAc)L]) complexes containing deprotonated pyrazolones L- formed by metal-induced cyclization of the starting HTSC ligands. All the complexes isolated were characterized by IR spectroscopy in the solid state and by 1H and 13C NMR spectroscopy in DMSO solution; in addition, crystals containing [Pb(L6)2] and [Pb(L7)2] were examined by X-ray crystallography. [Pb(L6)2] · 0.5H2O · 0.3MeOH (HL6 = 4-ethyl-2,5-dihydro-3-methyl-5-oxo-1H-pyrazole-1-carbothiamide) showed three types of molecule with significant structural differences that appear to be determined by packing interactions. In all three molecules the Pb?Pb distances are very short [3.6096(8)-3.7562(8) A?], but density-functional-theoretic calculations at the B3LYP level do not support the existence of Pb-Pb bonds. In [Pb(L7)2] (HL7 = N-ethyl-2,5-dihydro-3-methyl-5-oxo-1H-pyrazole-1-carbothiamide) all the molecules are of a single type, and they are linked in a three-dimensional network by weak intermolecular Pb?O bonds.
