Tetraphenylborate adducts of lead(II) co-ordinated by imidazole-functionalized 1,4,7-triazacyclononanes: crystal and molecular structures

Abstract

The new functionalized macrocycles 1-(1-methylimidazol-2-ylmethyl)-1,4,7-triazacyclononane, L¹, 1,4-bis(1-methylimidazol-2-ylmethyl)-1,4,7-triazacyclononane, L², and 1,2-bis[4,7-bis(1-methylimidazol-2-ylmethyl)-1,4,7-triazacyclonon-1-yl]ethane, L³, have been synthesized. The reaction of hydrated lead(II) acetate with these compounds in the presence of sodium tetraphenylborate afforded the complexes [PbL¹Cl(BPh₄)]·0.5MeCN, [PbL²(BPh₄)]BPh₄ and [Pb₂L³(BPh₄)₂][BPh₄]₂·4MeCN which were characterized in the solid state by elemental analyses and X-ray crystallography. The lead(II) atoms are co-ordinated by the nitrogens of the macrocyclic ring, by the nitrogen donor(s) of the pendant imidazole group(s) and, in the complex with the L¹ ligand, also by a chlorine atom. In each of the three complexes a phenyl group of a tetraphenylborate anion lies at close contact distance from the lead and completes its co-ordination.