Combination of metal-metal bonding and antiferromagnetic exchange interaction in the d{sup 2}-d{sup 2} complex [V{sub 2}O(SPh){sub 4}(Me{sub 2}-bpy){sub 2}]{center_dot}THF (Me{sub 2}-bpy = 4,4{prime}-dimethylbipyridine)
- Indiana Univ., Bloomington, IN (United States)
Synthetic procedures leading to the preparation of V{sup III} and V{sup IV} complexes of PhS{sup {minus}} are described, including the mononuclear complex (NEt{sub 4})[V(SPh){sub 4}(bpy)] (1). Controlled aerial oxidation of its 4,4{prime}-Me{sub 2}-bpy (Me{sub 2}-bpy) analogue generated in situ with 0.5 equiv of O{sub 2} leads to generation of [VO(SPh){sub 3}(Me{sub 2}-bpy)]{sup {minus}} that can be isolated as the NR{sub 4}{sup +} salts; (NMe{sub 4})[VO(SPh){sub 3}(Me{sub 2}-bpy)] (2) has been structurally characterized and contains a distorted-octahedral anion with three equatorial PhS{sup {minus}} groups and one Me{sub 2}-bpy N atom of the chelate trans to the multiply-bonded O atom. The same oxidation reaction with the related ion [V(SPh){sub 2}(bpy){sub 2}]{sup +} leads to [VO(SPh)(bpy){sub 2}](PF{sub 6}) (3). Controlled hydrolysis of [V(SPh){sub 4}(Me{sub 2}-bpy)]{sup {minus}}, generated in situ, leads to isolation of V{sub 2}O(SPh){sub 4}(Me{sub 2}-bpy){sub 2} (4) which has a [V{sub 2}({mu}-O)({mu}-SPh){sub 2}]{sup 2+} core with a terminal PhS{sup {minus}} and chelating Me{sub 2}-bpy on each metal; the V-V separation of 2.579(3) {angstrom} is suggestive of a V{sup III}-V{sup III} single bond. EHT calculations on the model complex V{sub 2}O(SH){sub 4}(NH{sub 3}){sub 4} indicate a V-V {sigma} bond arising from V d{sub z}{sup 2} overlap, with the HOMO and LUMO comprising {delta} and {delta}{sup *} orbitals, respectively, formed by V d{sub xy} orbitals. A small HOMO-LUMO gap ({approx}0.02 eV) suggests the weak room-temperature paramagnetism is due to thermal population of the LUMO. Variable-temperature solid-state studies on 4 indicate an effective magnetic moment per dimer ({mu}{sub eff}/V{sub 2}) of 1.35 {mu}{sub B} at 330 K decreasing to 0.095 {mu}{sub B} at 5.0 K.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 450714
- Journal Information:
- Inorganic Chemistry, Vol. 34, Issue 6; Other Information: PBD: 15 Mar 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Synthesis and electrochemistry of ([mu]-oxo)technetium complexes with bipyridine and halide ligands. Crystal structures of ([mu]-O)[X(bpy)[sub 2]Tc][sub 2]X[sub x][center dot]bpy (X = Cl, Br) and ([mu]-O)[Cl(phen)[sub 2]Tc][sub 2]Cl[sub 2]
Preparation and properties of models for the photosynthetic water oxidation center: Spin frustration in the (Mn sub 4 O sub 2 (O sub 2 CR) sub 7 (pic) sub 2 ) sup minus anion
Related Subjects
VANADIUM COMPLEXES
MAGNETIC PROPERTIES
STRUCTURAL CHEMICAL ANALYSIS
CHEMICAL PREPARATION
OXIDATION
NUCLEAR MAGNETIC RESONANCE
ANTIFERROMAGNETISM
MAGNETIC MOMENTS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
MATHEMATICAL MODELS
X-RAY DIFFRACTION
CRYSTAL STRUCTURE