Tuning the lead complexes based on a double 1,10-phenanthroline derivative with versatile coordination behavior by dicarboxylates: from 0D nano-ring to an unprecedented 0D + 3D cocrystal

Abstract

Three lead metal–organic complexes, namely, [Pb(tpphz)(L¹)(H₂O)]·3H₂O (1), [Pb(tpphz)_1.5(L²)_0.5(NO₃)]·H₂O (2) and [Pb₃(tpphz)₂(L³)₃]·2H₂O (3) {H₂L¹ = biphenylethene-4,4′-dicarboxylic acid, H₂L² = decanedioic acid, H₂L³ = octanedioic acid, tpphz = tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j]phenazine} have been synthesized by employing a double phenanthroline derivative tpphz as the main ligand in the presence of different organic dicarboxylates under hydrothermal conditions. Single crystal X-ray diffraction analyses reveal that a bimetallic nano-ring complex (1) was obtained by using a long and rigid aromatic dicarboxylate (L¹), and a 1D zigzag coordination polymer (2) was synthesized in the presence of a flexible fatty dicarboxylate (L²). When a shorter flexible fatty dicarboxylate (L³) was used then an unprecedented 0D + 3D cocrystal (3) was prepared. The tpphz ligands exhibited versatile coordination modes. The organic dicarboxylates with different flexibility and spacer length play an important role in adjusting the dimensions of the title lead complexes. Moreover, the thermal stability and fluorescent properties of complex 3 were also investigated.