A Coordination Chemistry Study of Hydrated and Solvated Cationic Vanadium Ions in Oxidation States +III, +IV, and +V in Solution and Solid State

Abstract

The coordination chemistry of hydrated and solvated vanadium(III), oxovanadium(IV), and dioxovanadium(V) ions in the oxygen donor solvents water, dimethylsulfoxide (dmso) and N,N′-dimethylpropyleneurea (dmpu) has been studied in solution by EXAFS and large angle X-ray scattering (LAXS) and in solid state by single crystal X-ray diffraction and EXAFS. The hydrated vanadium(III) ion has a regular octahedral configuration with a mean V-O bond distance of 1.99 Å. In the hydrated and dimethylsulfoxide solvated oxovanadium(IV) ions vanadium binds strongly to an oxo group at ca. 1.6 Å. The solvent molecule trans to the oxo group is very weakly bound, at ca. 2.2 Å, while the remaining four solvent molecules, with a mean V-O bond distance of 2.0 Å, form a plane slightly below the vanadium atom; the mean O=V-Operp bond angle is ca. 98°. In the dmpu solvated oxovanadium(IV) ion, the space demanding properties of the dmpu molecule leaving no solvent molecule in the trans position to the oxo group which reduces the coordination number to 5. The O=V-O bond angle is consequently much larger, 106°, and the mean V=O and V-O bond distances decrease to 1.58 and 1.97 Å, respectively. The hydrated and dimethylsulfoxide solvated dioxovanadium(V) ions display a very distorted octahedral configuration with the oxo groups in cis position with mean V=O bond distances of 1.6 Å and a O=V=O bond angle of ca. 105°. The solvent molecules trans to the oxo groups are weakly bound, at ca. 2.2 Å, while the remaining two have bond distances of 2.02 Å. The experimental studies of the coordination chemistry of hydrated and solvated vanadium(III,IV,V) ions are complemented by summarizing previously reported crystal structures to yield a comprehensive description of the coordination chemistry of vanadium with oxygen donor ligands.

Detailed magnetic analysis and successful deep-neural-network-based conformational prediction for [VO(dmso)5][BPh4]2

“…Although the disorder was observed around one of the dmso moieties [S(5A), C(9A), C(10A)], we will discuss only the main structure, because the occupancy of the minor structure is small 13 the conformations of the cations are different from each other with respect to the orientation of the terminal methyl groups, although the central VO 6 S 5 units have the same defect S 6 symmetry. In 2, oxido oxygen is hydrogenbonded to a dmso methyl group of the adjacent complex cation, forming a one-dimensional chain structure of the complex cations, while the cation is isolated from the others in 1.…”

Preconcentration and Determination of Trace Vanadium(V) in Beverages by Combination of Ultrasound Assisted-cloud Point Extraction with Spectrophotometry

“…33 The V(V) ion is often present in forms of VO 2 + (pH < 3.5), H 2 VO 4 − or VO 2 (OH) 2 -(pH 3.5-7.5) and HVO 4 2− or VO 3 (OH) 2-(pH 7.513.0). 40,41 However, V(IV) starts to hydrolyze and dimerize at pH 4.0; the pK a value of the [VO(H 2 O) 5 ] 2+ ion has been noticed to be in the range 5.3-6.0. At pH 5.0, insoluble VO(OH) 2 starts to form, which turns into water-soluble [(VO) 2 (OH) 5 ] − and [VO(OH) 3 ]complexes in strongly alkaline aqueous solution.…”

Investigation of crossover processes in a unitized bidirectional vanadium/air redox flow battery

“…In the case of V 2þ and V 3þ with D V 3þ ; N117 z0:5$D V 2þ ; N117 , V 3þ is either interacting stronger with the sulfonate groups than V 2þ so that it becomes less mobile within the membrane or the interactions are so poor that V 3þ only reaches a low concentration within the membrane. In aqueous solution, V 2þ and V 3þ both exist as hexaaquaions [22,24,59,60] [21,24]. The V 3þ complex with the sulfate ion carries a lower positive charge than the V 2þ complex.…”