A New Approach to Novel Cluster Compounds of Lead(II) Phosphonates

Five new lead(II) sulfonate‐phosphonates, namely [Pb 3 (L) 2 (H 2 O) 2 ] · 4H 2 O ( 1 ), [Pb(HL)(phen)] · H 2 O ( 2 ), [Pb 6 (L) 4 (phen) 8 ] · 3H 2 O ( 3 ), [Pb 6 (L) 4 (phen) 10 ] · 2H 2 O ( 4 ), and [Pb 6 (L) 4 (4,4′‐bipy)(H 2 O) 2 ] · 2H 2 O ( 5 ; H 3 L = m ‐HO 3 S‐C 6 H 4 ‐PO 3 H 2 , phen = 1,10‐phenanthroline, 4,4′‐bipy = 4,4′‐bipyridine) have been prepared and structurally characterized. Compound 1 features a novel 3D framework in which 1D chains of Pb 3 O 4 cluster units are further bridged by sulfonate‐phosphonate ligands, whereas compound 2 features a layer structure in which 1D chains of Pb 2 O 4 clusters are further bridged by sulfonate‐phosphonate ligands. Compounds 3 and 4 represent the first zero‐dimensional lead(II) phosphonates and feature novel isolated hexanuclear lead(II) clusters in which six Pb II ions are bridged by two tetradentate and two pentadentate phosphonate groups. Compound 5 features a 3D framework that is similar to that in compound 1 despite the different coordination modes for some sulfonate groups of the ligands. The main difference is that an aqua ligand in compound 1 is replaced by a nitrogen atom of the 4,4′‐bipy ligand, which results in the splitting of the large cavities in compound 1 into two small apertures in compound 5 . Compounds 1 and 5 exhibit strong broad blue fluorescent emission bands at 398 and 420 nm, respectively.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)