Mixed-Valence and Neutral Framework Inorganic−Organic Hybrid Materials:  Synthesis, Characterization, and Magnetic Properties of [{Co(N(CH)₄N)}(V₂O₅)₂] and [{Co(N(CH)₄N)}V₂O₆]

Abstract

Two inorganic−organic hybrid materials [{Co(N(CH)4N)}(V2O5)2] (1) and [{Co(N(CH)4N)}V2O6] (2) have been synthesized and characterized by FT-IR spectroscopy, thermogravimetric analysis, elemental analysis, manganometric titration, temperature-dependent magnetic susceptibility measurement, bond valence sum calculations, and single-crystal X-ray diffraction analyses. The neutral framework materials were prepared by the amalgamation of vanadium oxide chains and layers with metal−organoamine coordination polymers. The three-dimensional framework structures of the crystals in 1 and 2 are composed of vanadium oxide layers (1) and chains (2) combined with {Co(N(CH)4N)}2+ motifs that cross-link the reduced vanadium oxide layers (containing mixed-valent vanadium centers) in 1 and oxovanadium chains in 2. Besides crosslinking the metal oxide chains and layers in these materials, cationic metal−pyrazine polymers provide charge balance leading to the neutral framework in these solids. The compounds show good thermal stability. Crystal data for 1 is as follows: C4H4N2O10CoV4, orthorhombic space group Cmcm, a = 14.3071(6), b = 6.9965(3), c = 11.4510(5) Å, V = 1146.24(9) Å3, Z = 4, D calcd = 2.913 Mg·m-3, R1 = 0.0385 (all data), wR2 = 0.1019. Crystal data for 2 are as follows: C4H4N2O6CoV2, orthorhombic space group Pnna, a = 10.2524(8), b = 11.5653(9), c = 7.4719(6) Å, V = 885.96(12) Å3, Z = 4, D calcd = 2.526 Mg·m-3, R1 = 0.0199 (all data), wR2 = 0.0547.

Hydrothermal synthesis and structure of an open-framework, large-channel vanadium–cobalt phosphate [C4H12N2]2[CoII(H2O)2(VVO2)2(VIVO)2(PO4)4]·2H2O

“…In addition, bond valence sum (BVS) calculations [13] confirm that, the oxidation states of V(1), V(2), V(3) and Co are +5, +4, +4 and +2, respectively (valence sum 5.02, 3.98, 3.96 and 2.07, respectively) [14]. Also, the results of the BVS analyses (Table S2) are consistent with the coordination chemistry of vanadium [15] and charge balance requirements of the compounds [16].…”

Three new 3-D inorganic–organic coordination polymers constructed from polyoxovanadate-based heterometallic network and flexible bis(imidazole) ligand: Syntheses, structures and properties

“…In addition, the modification of the hydrothermal synthesis conditions, such as time, temperature, stoichiometry, pH, concentration and filling factor allows a partial control of the degree of oxoanion polymerization giving rise to different stable species in solution [12][13][14][15][16][17][18][19][20]. Examples of those are {V 4 …”

Hybrid materials composed of tetravanadate motifs: Synthesis, structure and magnetic properties of the open framework structure solids [{M(C5H5N)4}2]V4O12 (M=Cu, Co)

“…In this approach, hybrid materials containing neutral framework structures are generated by combining anionic oxovanadate building units with metal-organic cationic complexes. Our effort has led to the synthesis and characterization of a variety of novel materials [27][28][29][30][31][32][33][34][35][36].…”