Dynamic Behaviour, Solution and Crystal Structure of an Allylmolybdenum/Oxo/Hydroxo Heterocubane

Abstract

The synthesis of a highly unsymmetrical, chiral oxometallocubane anion [{(π‐C3H5)Mo(CO)2}4(µ3‐OH)3(µ3‐O)]− built up from organometallic moieties and oxo ligands is described. Its structure was investigated not only in the solid state (X‐ray diffraction analysis) but also in solution applying modern sophisticated NMR techniques. It was thereby possible to identify a trigonal twist rearrangement as the process responsible for the fluxional behaviour of this compound in solution: the (π‐allyl)Mo moieties are highly mobile, rotating on the “oxo surface” even at −65 °C. This complex can be regarded as a suitable model for (π‐allyl)Mo units incorporated into molybdenum oxide surfaces.

The Combination of Organometallic {Mo(η3-allyl)(CO)2(phen)} Fragments and Hard Aquo and Hydroxo Ligands: Controlled Synthesis and Structural Characterization

“…Although compounds with OH bridges between {Mo(η 3 -C 3 H 5 )(CO) 2 } fragments are known, 3a , b are the first complexes with a hydroxo group as a single bridge between two molybdenum fragments. The Mo−O−Mo angle in 3a (145.3(4)°) is, as expected, larger than in species with several OH bridges 4b,e-f and similar to the Mo−Cl−Mo angle (134.0(1)°) in [{Mo(η 3 -C 3 H 5 )(CO) 2 (bipy)} 2 (μ-Cl)]BF 4 .…”

“…As a continuation of these studies, we sought to prepare the analogous hydroxo derivatives . Examples of complexes containing {Mo(η 3 -allyl)(CO) 2 } fragments bridged by hydroxo groups are known; however, monometallic compounds of this kind have not been reported. In fact, and despite the extensive studies conducted on the chemistry of Mo(II) carbonyl compounds, mononuclear hydroxo complexes remain unknown, and the first mononuclear organometallic compound of Mo(II) (without carbonyls) containing a terminal hydroxo ligand, namely, [Mo(η 5 -C 5 H 5 )(OH)(PMe 3 ) 2 ], has been reported only recently .…”

High oxidation state organomolybdenum and organotungsten chemistry in protic environments

“…The behaviour of these compounds in water or in the presence of protic reagents does not appear to have been explored. A number of carbonyl-based allyl derivatives containing also hydroxido or aqua ligands are known in lower oxidation states [64][65][66], but oxidative processes leading to higher oxidation state derivatives have not so far been reported.…”

12 Chromium, molybdenum and tungsten

“…It is suggested that this complex could be a suitable model for (π-allyl)Mo units incorporated into molybdenum oxide surfaces. 205 O have all been isolated and their semiconducting properties have been investigated. 215 The cluster [{Rh(PPh 3 ) 2 }-(µ 3 -S)(µ-S) 3 {Mo(dedtc)} 2 (µ-Cl)] reacted readily with PhC 2 H to give [{Rh(SCPh᎐ ᎐ CH)Cl(PPh 3 )}{Mo(SCPh᎐ ᎐ CH)(dedtc)}{Mo(S 2 C 2 HPh)(dedtc)}].…”