Spontaneous self assembly of the {M₂(µ-O)(µ-MeCO₂)₂}²⁺core. Synthesis, structure, and properties of the binuclear vanadium(III) complex

Synthesis, characterization, and molecular structures of a series of [(3,5-dimethylpyrazolyl)borato]vanadium(III) and -(IV) complexes

“…N (22) -2136 ( 8) 1957 (5) 8089 ( 9) 37 (4) C (11) 2468 ( 12) 1205 ( 7) 9686 ( 11) 46 (5) C( 13) 2344 ( 13) 494 ( 7) 8481 ( 12) 52 ( 6) C (21) -3202 ( 12) 1912 ( 7) 7959 ( 12) 47 ( 5) C(23) -2502 ( 12) 2632 ( 6) 6985 ( 11) 38…”

Structural and Spectroscopic Evidence for the Formation of Trinuclear and Tetranuclear Vanadium(III)/Carboxylate Complexes of Acetate and Related Derivatives in Aqueous Solution

“…A further reason for our interest in aqueous vanadium(III)/carboxylate chemistry concerns recent reports of polynuclear V III complexes isolated from organic solvents or neat carboxylic acid solutions with interesting structures, spectroscopic properties, and magnetic properties. − Dimeric, trimeric, tetranuclear, octanuclear, and decanuclear vanadium(III)/carboxylate complexes have been isolated. V III complexes have potentially interesting magnetic properties, − ,− including switching between strong ferromagnetic coupling and antiferromagnetic coupling upon protonation of the μ-oxo ligand of dimeric V III complexes, − , exhibiting spin-frustration effects and/or single-molecule magnetic behavior. , Vanadium(III)/ carboxylate chemistry is also of interest in the development of new microporous materials . Finally, we note that, because NMR and EPR spectroscopies are generally unhelpful in studying V III speciation, an increasing number of potentiometric and UV−vis spectroscopic titration studies are being performed to elucidate the species formed between V III (aq) and biogenic ligands and to determine the associated acid dissociation and stability constants. ,− However, to obtain useful acid dissociation and stability constant data for these complex systems from potentiometric and UV−vis spectroscopic data, there is an urgent need for reliable structural models for multinuclear oxo- and hydroxovanadium(III) complexes formed in aqueous solution …”

“…[21][22][23][24][25][26][27][28][29] Dimeric, trimeric, tetranuclear, octanuclear, and decanuclear vanadium(III)/carboxylate complexes have been isolated. V III complexes have potentially interesting magnetic properties, [23][24][25][26][27][30][31][32][33][34][35][36] including switching between strong ferromagnetic coupling and antiferromagnetic coupling upon protonation of the µ-oxo ligand of dimeric V III complexes, [25][26][27]31 exhibiting spin-frustration effects 37 and/ or single-molecule magnetic behavior. 24,30 Vanadium(III)/ carboxylate chemistry is also of interest in the development of new microporous materials.…”

Characterization of Novel Vanadium(III)/Acetate Clusters Formed in Aqueous Solution

“…Analysis of the species present in solution is further complicated by the fact that paramagnetic (d 2 ) vanadium(III) complexes are generally both NMR and EPR silent-EPR spectroscopy signals are typically not observed, since spin−orbit coupling results in a large zero-field splitting and short spin−lattice ( T 1 ) relaxation times . Studies on vanadium(III)/carboxylate complexes isolated from organic solvents and/or neat carboxylic acid solutions have led to the characterization of dinuclear, − trinuclear, ,− tetranuclear, , and octanuclear 18 V(III)/carboxylate clusters with interesting and unusual spectroscopic and magnetic properties. In contrast, very little is known about the formation, structures, and properties of vanadium(III)/carboxylate complexes in aqueous solution. ,,− In this communication, mass spectrometry and X-ray structural data are presented as evidence for the formation of trinuclear and tetranuclear vanadium(III)/acetate clusters in acidic aqueous solution.…”