Mono- and binuclear molybdenum and tungsten complexes containing asymmetric bridging ligands: Effects of ligand conjugation and conformation on metal-metal interactions
- Univ. of Bristol (United Kingdom)
The authors have prepared the new monodentate ligands 4-(4-methoxyphenyl)pyridine, 1-(4-pyridyl)-2-(4-methoxyphenyl)ethene, 1-(4-pyridyl)-2-(3-methoxyphenyl)ethene, and 1-(3-pyridyl)-2-(4-methoxyphenyl)ethene (L[sup 5]-L[sup 8]); demethylation of the methoxy group in each case afforded the new bridging bidentate ligands HL[sup 1]-HL[sup 4], which contain one pyridyl and one phenolate donor. Attachment of a MoL*(NO)Cl [L* = hydrotris(3,5-dimethylpyrazolyl)borate] moiety to the pyridyl groups of L[sup 5]-L[sup 8] gave the 17-electron complexes [Mo(NO)L*ClL[prime]] (L[prime] = L[sup 5]-L[sup 8], complexes 5-8). Reaction of HL[sup 1]-HL[sup 4] with [M(NO)L*Cl[sub 2]] (M = Mo, W) afforded the mononuclear 16-electron complexes [M(NO)L*ClL[prime]] (M = Mo, L[prime] = L[sup 1]-L[sup 4], complexes 1-4; M = W, L[prime] = L[sup 1]-L[sup 4], complexes 13-16), in which the phenolate terminus of L[sup 1]-L[sup 4] is attached to the metal and the pyridyl group is pendant in each case. The pyridyl groups were N-methylated with CH[sub 3]I to afford [9][sup +]-[12][sup +] and [17][sup +]-[20][sup +], respectively. Alternatively, a second MoL*(NO)Cl could be attached to the pendant pyridyl groups of 1-4 to give the binuclear complexes [Mo(NO)L*Cl([mu]-L[prime])Mo(NO)L*Cl] (L[prime] = L[sup 1]-L[sup 4], complexes 21-24), which contain a 16-electron Mo center at the phenolate terminus and a 17-electron Mo center at the pyridyl terminus. Electrochemical studies showed that the anodic shift of the 16e-17e reduction due to N-methylation in [9][sup +]-[12][sup +] and [17][sup +]-[20][sup +] varies with the ligand in the order L[sup 1] > (L[sup 2] [approx] L[sup 4]) > L[sup 3]. 33 refs., 7 figs., 8 tabs.
- OSTI ID:
- 6258064
- Journal Information:
- Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 32:10; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400400* -- Electrochemistry
CATIONS
CHARGED PARTICLES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CHEMISTRY
COMPLEXES
ELECTROCHEMISTRY
ELECTRON SPIN RESONANCE
IONS
LIGANDS
MAGNETIC RESONANCE
MOLECULAR STRUCTURE
MOLYBDENUM COMPLEXES
REDUCTION
RESONANCE
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
TUNGSTEN COMPLEXES