Carbene complexes. Part 13. The synthesis and characterisation of secondary carbene complexes of vanadium(I), chromium(0), molybdenum(0), tungsten(0), manganese(I), rhenium(I), iron(0), ruthenium(II), cobalt(I), iridium(III), and platinum(IV), and hydridorhodium(III)

Abstract

Carbene Complexes. Part 13.l The Synthesis and Characterisation of Secondary Carbene Complexes of Vanadium(!), Chromium(o), Molybdenum(o), Tungsten@), Manganese([), Rhenium( I), Iron(o), Ruthenium(ii), Cobalt( I), Iridium( ill), and Platinum(iv), and Hydridorhodium(iii) t

N-Heterocyclic Carbene Complexes of Copper, Nickel, and Cobalt

“…A large literature covers the field of N -heterocyclic carbene (NHC) complexes of cobalt. Early work includes studies by Lappert where NHC-Co complexes were accessed from electron-rich alkenes. ,− These reports have not been included in this review. Although the largest part is concentrated on the three “easily” accessible oxidation states Co I , Co II , and Co III , recent reports describe the synthesis of highly reduced Co 0 and Co –I complexes or of highly oxidized complexes (formally Co IV or Co V ) stabilized by NHC donors.…”

Synthesis of monodentate bis(N-heterocyclic carbene) complexes of iridium: Mixed complexes of abnormal NHCs, normal NHCs, and triazole NHCs

“…One exception is the limited number of Rh and Ir NHC complexes with two dissimilar NHC ligands bound to the metal, that is, complexes in which the two NHC ligands differ in their steric or electronic properties. While many examples of chelating [5] and monodentate bis(NHC) or tris(NHC) [6][7][8][9][10][11][12][13][14][15][16][17][18] complexes of Rh and Ir are known, to the best of our knowledge only a few have been reported in which electronically or sterically distinct types of NHC ligands are present [17,19]. Given the importance of both steric and electronic dissymmetry in many catalytic reactions [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36], we sought a facile method to reliably synthesize monodentate bis(NHC) complexes in which the two NHC ligands are sterically and/or electronically distinct.…”

“…(1,4-Dimethyl-1,2,4-triazol-5-ylidene)(1-isopropyl-2,4-diphenyl-3-methylimidazol-5-ylidene)(g 4 -1,5-cyclooctadiene)iridium (I) hexafluorophosphate(8) …”

Cationic Pt(IV) Tp' carbenes

“…[1,[12][13][14][15][16][17][18][19][20][21][22][23][24] Such high oxidation state species have been postulated as intermediates in insertion reactions of diazo compounds and in elimination processes from platinumcycloalkanes. [25,26] Additionally, it has been noted that cationic Pt(IV) carbenes represent an unusual subset of carbenes that in some ways lie between traditional Fischer-type complexes of low-oxidation-state late transition metals and Schrock-type carbenes of highoxidation-state early transition metals.…”

“…This method has been successful for both simple Pt(II) carbenes [12][13][14] and for platinum carbene complexes containing ancillary N-heterocyclic carbene ligands. [23,24] Alternatively, the carbene ligand can sometimes be installed during the oxidative addition step by using organic [1,15,16] For example, Puddephatt and co-workers demonstrated that the addition of chloroiminium salts, such as [ClXC=NMe 2 ]Cl (X= H or Cl), to PtMe 2 ( t Bu 2 bpy) generates Pt(IV) carbenes of the type ( t Bu 2 bpy)PtClMe 2 (=CXNMe 2 ) in good yield (Scheme 1, b). [1] Clark et.…”