Thermally stable lead(II) amidinates and guanidinates

Stasch, Andreas;Forsyth, Craig M.;Jones, Cameron;Junk, Peter C.

Abstract

The reactions of lithium amidinates and guanidinates [Li(Fiso)] (Fiso = N, N'-bis(2,6-diisopropylphenyl) formamidinate), [Li(Piso)] (Piso = N, N'-bis(2,6-diisopropylphenyl)( tert-butyl) amidinate), [Li(CyG)] (CyG = N, N ''-bis(2,6-diisopropylphenyl)-N', N'-dicyclohexylguanidinate) and [Li(HDG)] (HDG = N, N ''-bis(2,6-diisopropylphenyl)-N'-(2,6diisopropylphenyl) guanidinate) with anhydrous PbCl(2) in THF afforded the amidinate complexes [Pb(Fiso)(2)] 1, and [Pb(Piso)Cl](2) 2, and the guanidinate complexes [Pb(CyG)Cl](2) 3, and [Pb(HDG)Cl](2) 4 in moderate yields. The complexes are thermally stable, 2, 3 and 4 decompose between 163-202 degrees C whilst 1 melts with decomposition to lead metal at 310 degrees C. 2, 3 and 4 are unsymmetrical dimers in the solid state but their NMR data suggested fluxional behaviour in solution. Storing the yellow crystals of [Pb(CyG)Cl](2) 3 for one week in the perfluorinated crystallography oil under air resulted in oxygen incorporation into one isopropyl group of the CyG ligand giving a mixed amidinate-alkoxide dianion (CyGO) and afforded some new colourless crystals of [(CyGO) Pb](2) 5 that were characterised by a X-ray single crystal structure determination.

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New Journal of Chemistry

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1369-9261

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Royal Society of Chemistry

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DOI

10.1039/b718537e