Synthesis and crystal structure of a novel Zn(II) 2-D coordination polymer containing 1,3-bis(4-pyridyl)propane ligand and Croconate Violet dianion

From the reaction between Zn(NO3)2 · 6H2O and tetrabutylammonium croconate violet ((NBu4)2CV) in the presence of the flexible ligand 1,3-bis(4-pyridyl)propane (BPP) a novel neutral 2-D coordination polymer {[Zn(μ-BPP)(BPP)(CV)(H2O)] · H2O}n (1) was obtained. Compound 1 was characterized by means of elemental analysis, thermogravimetric analysis and vibrational spectroscopy. The crystal structure of 1 reveals that each Zn(II) is coordinated by three nitrogen atoms from two different BPP ligands, two oxygen atoms from one Croconate Violet dianion and one aqua ligand, within a distorted octahedral geometry in a facial arrangement (ZnN3O3). One of the BPP ligands adopts a TG (trans–gauche) conformation bridging two zinc centers giving rise to a 1-D polymeric chain along the crystallographic a axis, and the other is coordinated to metal site in a monodentate fashion adopting a TT (trans–trans) conformation. Adjacent 1-D chains are extended into a 2-D coordination network of (4, 4) topology through cooperative hydrogen bonding involving N31, OW2 and OW1 atoms, in direction of the c axis. Two complementary 2-D sheets fit each other exhibiting an interdigitation phenomenon, giving rise to a bilayer supramolecular structure.

Reaction between Zn(II) cation and Croconate Violet dianion (CV2−) in the presence of the flexible nitrogen ligand 1,3-bis(4-pyridyl)propane (BPP) has afforded a novel neutral coordination polymer namely {[Zn(μ-BPP)(BPP)(CV)(H2O)] · H2O}n (1). Compound 1 was characterized by means of elemental analysis, thermogravimetric analysis and vibrational spectroscopy. The crystal structure of 1 reveals 1-D chains extended to a 2-D coordination network through hydrogen bonding.Figure optionsDownload as PowerPoint slide