Parallel Modes of C−H Bond Activation Initiated by Cp*Mo(NO)(CH₂CMe₃)(C₆H₅) at Ambient Temperatures

Abstract

The molybdenum nitrosyl complex Cp*Mo(NO)(CH2CMe3)(C6H5) reacts at room temperature via elimination of neopentane or benzene to form the transient species Cp*Mo(NO)(=CHCMe3) and Cp*Mo(NO)(eta2-C6H4). These reactive intermediates effect the intermolecular activation of hydrocarbon C-H bonds via the reverse of the transformations by which they are generated. Thermolysis of Cp*Mo(NO)(CH2CMe3)(C6H5) in pyridine yields the adducts Cp*Mo(NO)(=CHCMe3)(NC5H5) and Cp*Mo(NO)(eta2-C6H4)(NC5H5), and the benzyne complex has been characterized by X-ray diffraction.

Sequential Hydrocarbon C—H Bond Activations by 16-Electron Organometallic Complexes of Molybdenum and Tungsten

“…Its existence was first inferred from the remarkable reaction of Cp*Mo(NO)(CH 2 CMe 3 ) 2 (9) with CÔH 6 at room temperature that leads to the sequential activation of two molecules of benzene as depicted in Scheme 5 (9). These conversions resemble the sequential its chemistry may well resemble in some aspects that exhibited by the Cp*M(NO)(r| 2 -acetylene) intermediates which are considered in the next section.…”

“…For example, the reactions of 9 with tetramethylsilane or mesitylene for 30 h at 20 °C result in the clean formation of free neopentane and Cp*Mo(NO)-(CH 2 CMe 3 )(CH 2 SiMe 3 ) (10) or Cp*Mo(NO)(CH 2 CMe 3 )^2-CH 2 C 6 H 3 -3,5-Me 2 ) (11), respectively (9). Neither organometallic product undergoes further reactivity under these mild reaction conditions.…”

Methane: a new frontier in organometallic chemistry

“…108,109 Seminal examples of transition metal alkylidenes (Ti, V, Cr, Mo and W) have been shown to activate C-H bonds in an intermolecular fashion. [107][108][109][110][111][112][113][114][115] However, the use of the alkylidyne ligand has not been realized in the context of intermolecular C-H bond activation. In 1992 Basset et al reported that a transient tungsten alkylidyne could add a C-H bond intramolecularly.…”

The chemistry of the carbon–transition metal double and triple bond: annual survey covering the year 2002

“…243, Scheme 18) were proposed as intermediates in C-H activation reactions of dialkylmolybdenum complex 242 [463]. Room temperature thermolysis of complex 242 in benzene resulted in both the monophenyl complex 244 and the diphenyl complex 245.…”