Organometallic rhenium(iii) chalcogenide clusters: coordination of N-heterocyclic carbenes

Abstract

The preparation of rhenium based octahedral clusters containing N-heterocyclic carbenes is described. These represent the first examples of [M6(μ3-Q)8](n+) or [M6(μ3-X)8](n+) clusters to contain a carbene ligand of any type (NHC, Fischer or Schrock). Surprisingly, the NHC ligands attenuate their luminescent properties.

Crystal structure of octa-μ3-selenido-(p-toluenesulfonato-κO)pentakis(triethylphosphane-κP)-octahedro-hexarhenium(III)p-toluenesulfonate dichloromethane disolvate

“…While structural reports of rhenium chalcogenide clusters containing other oxygen donor ligands have been previously reported (Dorson et al, 2009;Mironov et al, 2011;Zheng & Holm, 1997;Zheng et al, 1999), this report represents the first example of tosylate coordination to a [Re 6 Q 8 ] 2+ cluster core. The average Re-P bond length of the five terminal PEt 3 ligands in the title compound [2.479 Å ] is similar to that in other rhenium selenide clusters containing PEt 3 ligands (Durham et al, 2012(Durham et al, , 2015Knott et al, 2013;Zheng & Holm, 1997;Zheng et al, 1999 = 95.9862 (12) = 100.0851 (11) V = 3629.9 (5) Å 3 Z = 2 Mo K radiation = 14.33 mm À1 T = 193 K 0.48 Â 0.28 Â 0.10 mm 2013, Yoshimura et al, 2000). Substitution of halide ligands can be facilitated by silver(I) salts, where the precipitation of AgX (X = halide) drives the substitution reaction (Zheng & Holm, 1999, Durham et al, 2012.…”

“…The tosylate ligand was our ligand of choice and here we report the preparation, characterization and X-ray structural analysis of [Re 6 Se 8 (PEt 3 ) 5 (OTs)](OTs)•2CH 2 Cl 2 . We recently substituted the tosylate ligand in this complex for a N-heterocyclic carbene which resulted in the formation of the first [M 6 Q 8 ] n+ complex to contain a carbene ligand (Durham et al 2015 (Dorson et al, 2009, Durham, et al, 2012, 2015, Knott et al, 2013, Mironov et al, 2011, Zheng & Holm 1997, Zheng et al 1999. The average Re-P bond distance of the five terminal PEt 3 ligands is 2.4790 Å which also similarly compares with other rhenium selenide clusters containing PEt 3 ligands (Durham, et al, 2012, 2015, Knott et al, 2013, Zheng & Holm, 1997, 1999.…”

N-Heterocyclic Carbenes in Materials Chemistry

“…Generally, the synthesis of NHC-protected metal chalcogenide cluster complexes involves either a direct self-assembly between the NHC−metal complex and a chalcogenide , 58,227 or exchange reactions of ligand-capped cluster complex with free NHCs. 223 Examples of both types of synthetic approaches are given, organized by metal, in the following sections. 58 Interest in these clusters stemmed from their use as models of the cysteinate-protected [Fe 4 S 4 ] 0 core of the iron protein of nitrogenase from Azotobacter vinelandii (Av2).…”

Recent progress on NHC-stabilized early transition metal (group 3–7) complexes: Synthesis and applications

“…Interestingly and surprisingly, the presence of the NHC ligands attenuate their luminescent properties. 209 Finally, Various rhenium (V or VII) NHC complexes have been prepared, including water stable or 188 Re radiolabeled species. 210,211,212,213 In total, 10 technetium NHC complexes have been characterized by X-ray diffraction studies and the bond distances range from 2.07 to 2.23 Å.…”