Luminescent zinc and cadmium complexes incorporating 1,3,5-benzenetricarboxylate and a protonated kinked organodiimine: From a hydrogen-bonded layer motif to thermally robust two-dimensional coordination polymers

• Published in: Journal of solid state chemistry 2007-06, Vol.180 (6), p.1852-1862
• Main Authors: Braverman, Maxwell A., Supkowski, Ronald M., LaDuca, Robert L.
• Format: Article
• Language: English
• Subjects: ABSORPTION SPECTROSCOPY; Benzenetricarboxylate; Cadmium; CADMIUM COMPLEXES; CADMIUM NITRATES; Condensed matter: structure, mechanical and thermal properties; Coordination polymer; Cross-disciplinary physics: materials science; rheology; Crystal structure; CRYSTALLOGRAPHY; Dipyridylamine; Exact sciences and technology; HYDROTHERMAL SYNTHESIS; IMINES; INFRARED SPECTRA; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LAYERS; LIGANDS; LUMINESCENCE; Materials science; MONOCLINIC LATTICES; MONOCRYSTALS; MORPHOLOGY; Organic compounds; Other materials; Physics; POLYMERS; Single-crystal and powder diffraction; Specific materials; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; THERMAL GRAVIMETRIC ANALYSIS; Thermogravimetric analysis; ULTRAVIOLET RADIATION; VISIBLE RADIATION; X-RAY DIFFRACTION; X-ray diffraction and scattering; Zinc; ZINC CHLORIDES; ZINC COMPLEXES
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2007.04.010

Hydrothermal treatment of zinc chloride, 1,3,5-benzenetricarboxylic acid (H 3BTC), and 4,4′-dipyridylamine (dpa) afforded two different complexes depending on reaction conditions, which were characterized by single-crystal X-ray diffraction, infrared spectroscopy, and elemental analysis. Under acidic conditions, a discrete neutral molecular species with formulation [Zn(HBTC) 2(Hdpa) 2] ( 1) was isolated, which aggregates into two-dimensional hydrogen-bonded layers. Under more basic conditions, the two-dimensional layered coordination polymer [Zn(BTC)(Hdpa)] ( 2) is obtained, which manifests covalent linkage of [Zn(BTC)(Hdpa)] serpentine chain motifs into 3-connected undulating 4.8 2 topology 2-D layers. Both 1 and 2 possess tetrahedral coordination at Zn. Use of cadmium nitrate in the synthesis resulted in [Cd(BTC)(H 2O)(Hdpa)] ( 3), which displays a similar layer topology as 2 but with significant adjustments imparted by octahedral coordination at Cd. In all cases, supramolecular hydrogen bonding promoted by Hdpa ligands provide an important assistive structure-directing role. All materials display blue luminescence upon excitation with ultraviolet light, ascribed to intraligand transitions. Crystallographic data: 1: monoclinic, C2/ c, a=25.389(6) Å, b=9.811(2) Å, c=17.309(4) Å, and β=128.957(3)°, 2: monoclinic, P2 1/ c, a=13.212(17)c, b=17.15(2) Å, c=7.506(10) Å, and β=93.71(2)°, and 3: monoclinic, C2/ c, a=14.241(6) Å, b=15.218(6) Å, c=17.976(7) Å, and β=109.330(6)°. Hydrothermal synthesis has afforded a family of luminescent complexes based on divalent d 10 cations with 1,3,5-benzenetricarboxylate (BTC) and 4,4′-dipyridylamine (dpa) ligands. [Zn(HBTC) 2(Hdpa) 2] ( 1) is a discrete neutral molecular species. [Zn(BTC)(Hdpa)] ( 2, pictured) and [Cd(BTC)(H 2O)(Hdpa)] ( 3) are 2-D coordination polymers with different morphologies depending on coordination geometry at the metal. All three materials exhibit blue–violet luminescence on exposure to ultraviolet radiation.