Facile Access of Well-Defined Stable Divalent Lead Compounds with Small Organic Substituents

摘要

The reaction of I equiv of beta-diketiminate lithium, LLi center dot OEt2 {L = HC(CMeNAr)(2) (Ar = 2,6-iPr(2)C(6)H(3)) nacnac ligand} with I equiv of PbCl2 in THF afforded the beta-diketiminate lead(II) chloride (1) as a yellow compound. Treatment of I with stoichiometric amounts of methyl lithium, phenyl lithium, lithium phenylacetylide, and silver triflate resulted in the divalent organolead compounds LPb(II)Me (2), LPb(11)Ph (3), LPb(II)CCPh (4), and LPb(II)OTf (5). Compounds 2 and 3 are the first stable, monomeric lead(II) derivatives involving small alkyl and aryl groups Me and Ph, respectively, supported by the beta-diketiminate ligand. Compound 4 is the first alkynyl lead(II) derivative. All compounds (2, 3, 4, 5) were characterized by microanalysis, X-ray crystallography, and H-1, C-13, and Pb-207 NMR spectroscopy. Single-crystal X-ray structural analyses indicate that compounds 2-4 are monomeric, and the lead center resides in a trigonal-pyramidal environment, whereas 5 has a polymeric structure. The results demonstrate the effectiveness of the beta-diketiminate ligand in creating a protected surrounding for the lead atom.