Novel scorpionate-type triscarbene ligands and their silver and gold complexes

Tris(carbene)borate Ligands Featuring Imidazole-2-ylidene, Benzimidazol-2-ylidene, and 1,3,4-Triazol-2-ylidene Donors. Evaluation of Donor Properties in Four-Coordinate {NiNO}10 Complexes

“…3 Tridentate ligands composed solely of NHC donors are mainly limited to a small number of C 3 -symmetric tripodal ligands in which three imidazol-2-ylidene donors are connected through a central linker atom or group. 4,5,6,7,8,9 …”

“…1) connect three imidazol-2-ylidene donors through a central borate linker. 4 First generation tris(carbene)borate ligands (R = Me, Et; R′ = H) have been used to prepare octahedral manganese, iron and cobalt complexes, 10,11 and more recently a copper(I) cluster. 12 Our group has developed synthetic routes for second generation tris(carbene)borate ligands in which the steric bulk has been increased (R = t Bu, Mes; R′ = H, Ph).…”

Theoretical investigation of the scope of sequential ligand tuning using a bifunctional scorpionate tris(1,2,4-triazolyl)borate-based architecture

“…More recently, the chemistry of complexes of these ligands and their bulkier second generation tris(imidazolylidene)borate complexes have been explored by several groups including that of Smith. [13][14][15][16][17][18] Just as scorpionate ligands moved beyond Tp to greater structural diversity, N-heterocyclic carbenes quickly moved beyond imidazole based frameworks. A commonly encountered analogue to imidazol-2-3 ylidenes are 1,2,4-triazol-5-ylidenes.…”

Syntheses, structures and electrochemical properties of homoleptic ruthenium(III) and osmium(III) complexes bearing two tris(carbene)borate ligands

“…Many polydentate N-heterocyclic carbenes have also been designed, and they allow preparation of organometallic compounds with a variety of geometries [6,7]. Among the polydentate N-heterocyclic carbenes, the tripodal tris(N-heterocyclic carbene)borate ligands (such as A and B, Chart 1), with a framework similar to that of the classic ligand tris(pyrazolyl)borate (Tp, C, Chart 1), have been of considerable interest due to their tripodal framework and chelating effect [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. In contrast to the versatile coordination and organometallic chemistry of tris(pyrazolyl)borate [27,28], metal complexes with tridentate N-heterocyclic carbene ligands A and B have been limited to several metal ions.…”

“…Tris(3-alkylimidazol-2-ylidene)hydroborate [HB(R-ImH) 3 ] (A, Chart 1) has been employed in the preparation of complexes of Fe(III) [8], Li(I) [9], Co(III) [10], Cu(I) [11,12], Ag(I), Au(I) [13], Mg(II), Fe(II) [14], Ni(II) [15], and Ca(II), Sr(II), Ba(II) [16]. Smith et al have modified the tris(3-alkylimidazol-2-ylidene)hydroborate [HB(R-ImH) 3 ] (A) to incorporate a phenyl group on the boron atom [PhB(R-ImH) 3 ] (R = Me, t Bu, Mes B, Chart 1) and reported novel Co(II)-amido [17], Co(III)-imido [18], Mn(IV) [19], four-coordinate Fe(II) complex PhB(MesIm) 3 Fe-N=PPh 3 [20], Fe(III)-imido [21], Fenitrido [22][23][24][25], and Fe(V)-nitrido [26] complexes, with interesting reactivities and properties.…”