Inorganic−Organic Hybrid Materials Containing Porous Frameworks:  Synthesis, Characterization, and Magnetic Properties of the Open Framework Solids [{Co(4,4‘-Bipy)}V₂O₆] and [{Co₂(4,4‘-Bipy)₃(H₂O)₂}V₄O₁₂]·2H₂O

Abstract

Synthesis of two novel porous framework hybrid materials, [Co(4,4′-bipy)V 2 O 6 ] (1) and [{Co 2 (4,4′-bipy) 3 (H 2 O) 2 }V 4 O 12 ]‚2H 2 O (2), and their characterization by infrared spectroscopy, thermogravimetry, elemental analysis, manganometric titration, surface area measurement, bond valence sum calculations, temperature-dependent magnetic susceptibility measurement, and single-crystal X-ray structure analyses is described. Both compounds exhibit remarkable thermal stability. The three-dimensional structures of 1 and 2 are composed of fused {VO 4 } motifs linked by {Co(4,4′-bipy)} coordination polymers. The structure of 1 is comprised of {CoO 3 N 2 } trigonal bipyramids, linked in two dimensions by corner-sharing {VO 4 } tetrahedra and in the third dimension by the 4,4′-bipyridine ligands. In the bimetallic layers, the cobalt centers are bridged alternately by {VO 4 } and {V 2 O 7 } units, generating alternating eightmembered {Co 2 V 2 O 4 } and twelve-membered {Co 2 V 4 O 6 } rings. The crystal structure of 2 consists of a novel three-dimensional network containing two types of octahedral Co 2+ ions linked by a {V 2 O 7 } group. The cobalt centers in 2 are linked in three dimensions by bridging 4,4′-bipyridine ligands. The structure contains rather large channels parallel to the c-axis. A disordered water molecule of crystallization is present in the channels. Crystal data for C 10 H 8 N 2 O 6 CoV 2 , 1: triclinic space group P1 h (No. 2), a ) 8.1517(4) Å, b ) 8.5794(4) Å, c ) 10.1233(5) Å, R ) 87.0170(10)°, ) 75.9610(10)°, γ ) 75.1740(10)°, V ) 663.94(6) Å 3 , Z ) 2, D calcd ) 2.066 Mg‚m -3 , R1 ) 0.0252 (all data), wR2 ) 0.0669. Crystal data for C 15 H 16 N 3 O 8 -CoV 2 , 2: monoclinic space group C2/c (No. 15), a ) 30.4457(13) Å, b ) 11.3540(5) Å, c ) 11.5836(5) Å, ) 106.5390(10)°, V ) 3838.6(3) Å 3 , Z ) 8, D calcd ) 1.824 Mg‚m -3 , final R1 ) 0.0447 (all data), wR2 ) 0.1259.

[Co2(ppca)2(H2O)(V4O12)0.5]: A Framework Material Exhibiting Reversible Shrinkage and Expansion through a Single‐Crystal‐to‐Single‐Crystal Transformation Involving a Change in the Cobalt Coordination Environment

“…It is well known that vanadium oxide groups are often engaged in the cross-linking of structural components and that they can promote the formation of unique structural geometries. [7] Whereas the coordination modes of the cobalt and the vanadium in this structure are fairly typical for these elements, surprising is the observation of dynamic structural changes that take place upon the thermal removal of both noncoordinated and coordinated water molecules, the process of which is highlighted herein.…”

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

“…Hybrid solids that combine both metal-oxide and organic ligand ''building blocks" are a growing class of new materials and are beginning to receive widespread attention because of their potential application in the fields of magnetism, catalysis and photochemistry [1][2][3]. Owing to the ability of vanadium to adopt a variety of coordinated geometries in various oxidation states, the influences of the second metal ions as well as the organic ligands on the structure could be significant.…”

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].…”