N‐Arylation and N,N‐Dibenzylation of Coordinated N₂ with Organic Halides; Differences in the Reactivity of trans‐[Mo(N₂)₂(Me₈[16]aneS₄)] and Its Phosphane Analogues

Abstract

The N2 ligand in the title complex (M8[16]anS4 = 3,3,7,7,11,11,15,15‐octamethyl‐1,5,9,13‐tetrathiacyclohexadecane) displays unprecedented reactivity. It reacts with aryl halides and benzyl bromide in toluene at room temperature without irradiation to give MoII aryldiazenido and dibenzylhydrazido complexes, respectively. Its reaction with methanol and acetone affords NH3 and Me2CNNCMe2, respectively. Phosphane analogues of the title complex do not undergo such reactions. The structure of trans [MoI(N2‐p‐C6H4CO2Me)(Me8[16]anS4)], the diazenido complex, is shown on the right.

Electrochemistry of molybdenum imides: cleavage of molybdenum–nitrogen triple bonds to release ammonia or amines †

“…1(b). This is consistent with cleavage of the metal-halide bond giving rise to the same product, trans-[Mo(NEt)(dppe) 2 ], equation (2). The release of halide following reduction of trans-[MoI(NEt)(dppe) 2 ] ϩ was confirmed by observation of the characteristic oxidative response of free iodide upon scan reversal.…”

“…The chemistry following the primary electron-transfer reaction of trans-[MoX(NR)(dppe) 2 ] ϩ leads to further electron transfer and the formation of a moderately stable five-coordinate, closed-shell molybdenum() product, trans-[Mo(NR)-(dppe) 2 ], equation (2). The evidence for the formation of the The reduction process at E p red = Ϫ2.21 V versus ferrocenium-ferrocene leads to the generation of a product which is detected on the reverse scan by its oxidation near Ϫ1.6 V. The peak-current function is independent of potential scan rate (ν) in the range 10 to 100 mV s Ϫ1 and corresponds to a diffusion-controlled two-electron reduction.…”

Conformational analysis of 14- and 16-membered unsaturated oxa, thia, and selena macrocyclic ligands

“…Cal-SUGVEV [48] SUGVIZ [48] THCDCU [56] TTCDCU10 [67] TTCDNI [95] TTDNBC 10 [50] PEVNEJ [107] PITVUJ [65] SONPIU [12] SONPOA [12] STHDMO [108] TOCYHX [72] TTHCTD [44] TTPHGC10 [66] VAZRET [83] VIMDOK [59] VURCIU [95] VURCOA [96] VAVNAH [109] VAZSIY [80] VAZSOE [80] VIXPOH [69] VIXPUN [69] VIZPUP [110] culations were performed on the free ligands alone with explicit lone pairs on oxygen donor atoms. The initial structures for minimization were imported from the CSD where suitable examples existed; otherwise the conformation was selected by the temporary imposition of appropriate torsional constraints.…”

Synthesis, spectroscopic and EXAFS studies of vanadium complexes of trithioether ligands and crystal structures of [VCl3([9]aneS3)] and [VI2(thf )([9]aneS3)] ([9]aneS3 = 1,4,7-trithiacyclononane)

“…1 This proposal is supported by the fact that the EXAFS spectrum of the vanadium nitrogenase cofactor resembles that of the synthetic cluster [VFe 3 S 4 Cl 3 (dmf) 3 ] Ϫ . 3 In view of this work, noting that the only well characterised metal-sulfur site at which dinitrogen is bound and reduced is in the thioether complex trans-bis-(dinitrogen) (3,3,7,7,11,11,15,15-octamethyl-1,5,9,13-tetrathiacyclohexadecane)molybdenum, 4 and in the knowledge that early transition metal thioether compounds are rare, we have initiated a study of vanadium thioether macrocyclic chemistry. In particular with regard to understanding the nature of the vanadium site in nitrogenase, we considered that as well as introducing the correct sulfur ligand environment at vanadium (three confacial S donors), macrocyclic trithioethers would also facilitate more stable complexes and may enable N-and O-donor ligands to be introduced at the other co-ordination sites.…”