Homoleptic carbene complexes

A Homoleptic Carbene-Lithium Complex

“…Further Fe III , Co III [12] (3), and Re VII complexes [13] with this ligand, as well as the corresponding ethyl derivate hydrotris-(3-ethylimidazolin-2-ylidene)-borate (TRIS Et ), were reported recently. In the synthesis of these compounds the ªfreeº monoanionic carbenes (TRIS R ), formed in situ from the corresponding hydrotris(3-alkylimidazolium)borate tetrafluoroborates by deprotonation with nBuLi, were treated directly with the corresponding metallic precursor.…”

“…[5a, 22] However, on coordination to a transition metal both opening of the N-C-N angle from 101 ± 1028 to 103 ± 1058 and a slight shortening of the NÀC(carbene) bond compared to that in the free N-heterocylic carbene have been discussed. [1,2] The comparison of 5 (103.7(2) ± 103.8(2)8; 1.361(3) ± 1.370(3) ) with the hexacarbene complex 3 that we have studied by X-ray diffraction [10,12] (104.5(4) ± 106.1(4)8; 1.345(6) ± 1.378(6) ) shows that the differences here lie within 3s; nor do other bond lengths, for example, those in the ring, show significant differences between 5 and the hexacarbene transition metal complexes 3. However, there are significant differences when the data are compared to those of the crystal structure of the trisimidazolinium salt 4.…”

Synthetic Bioinorganic Chemistry: Scorpionates Turn 50

“…The coordination chemistry of the tris(carbene)borates, first reported by Fehlhammer in 1996 [34], was very limited [97] until Smith et al described in 2005 an improved synthetic route to analogous ligands bearing bulkier alkyl and aryl substituents [98]. These ligands, like the ubiquitous N-heterocyclic carbenes (NHCs) [99,100], are primarily strong σ-donors and only weak π-acceptors [101].…”

Nickel(II) and Iron(II) Complexes with Tetradentate NHC/Amide Hybrid Ligands

“…6 2 Fe II ] (TRIS R = hydrotris(3-alkyl-imidazoline-2-yliden-1-yl)borate; R = Me, Et) synthesized by Fehlhammer et al [45]. The [(TRIS R ) 2 Fe II ]/[(TRIS R ) 2 Fe III ] + potential was determined at around − 0.7 V (value converted vs. NHE according to ref.…”