Lead(II) complexes with Kemp’s tricarboxylate: Can lone pair activity be discerned ?

Youssef Atoini (1) , Jack Harrowfield (1) , Pierre Thuéry (2)

1 ISIS - Institut de Science et d'ingénierie supramoléculaires
2 LCMCE - Laboratoire de Chimie Moléculaire et de Catalyse pour l'Energie (ex LCCEF)

Kemp's triacid (H3kta; cis,cis-1,3,5-trimethylcyclohexane-1,3,5-tricarboxylic acid) has been used to synthesize three lead(II) complexes under solvo-hydrothermal conditions. [Pb$_3$(kta)Cl$_3$] (1) and [Pb$_3$(H$_3$kta)(kta)$_2$] (2) are both diperiodic coordination polymers displaying hydrophobic surfaces with protruding methyl groups, complex 2 being isomorphous with an Sr$^{II}$ complex previously reported. In contrast, [Pb(Hkta)(phen)] (3), where phen is 1,10-phenanthroline, is a monoperiodic, helical coordination polymer. In all cases, Pb$^{II}$ cations are in seven-or eight-coordinate environments of predominantly hemidirected nature. The possible effects of the Pb$^{II}$ valence shell lone pair are discussed in terms of coordination geometry and Pb...H weak interactions as revealed on Hirshfeld surfaces. Only in complex 1 is a short Pb...H contact at 2.84 Å possibly indicative of appreciable basicity of the metal ion. All three complexes show similar weak luminescence, apparently independent of the nature of the ligands.

Mots clés: Carboxylic acids; Lead(II) cation; Luminescence properties; Metal-organic networks; Structure elucidation

Domaines: Cristallographie

Youssef Atoini, Jack Harrowfield, Pierre Thuéry. Lead(II) complexes with Kemp’s tricarboxylate: Can lone pair activity be discerned ?. Polyhedron, 2022, 218, pp.115760. ⟨10.1016/j.poly.2022.115760⟩. ⟨cea-03596707⟩