Early transition metal complexes with triphenolamine ligands: Synthesis and applications

Formate complexes of tri- and tetravalent titanium supported by a tris(phenolato)amine ligand

“…Due to the weaker trans -influence of the amine ligand compared to the phenoxy group, all Ti–O OCHO bonds trans to Ti–N bonds are relatively shorter ( d (Ti–O OCHO ) avg = 1.959 Å, ranging from 1.940(2) Å to 1.981(3) Å) compared to those in the cis position ( d (Ti–O OCHO ) avg = 2.072 Å, ranging from 2.045(2) Å to 2.103(2) Å). The C–O distances of the formato ligand which is directly bridging two titanium centers are nearly identical ( d (C4–O) = 1.220(3) and 1.241(4) Å) and those reported in the literature (1.245(14) Å and 1.193(15) Å) 11 or [{(N( t Bu)-3,5-Me 2 C 6 H 3 ) 3 Ti} 2 (μ-OCHO-η O :η O ′)][B(C 6 F 5 ) 4 ] (1.257(3) Å and 1.239(3) Å). 9 On the contrary, the C–O distances of the other six formato ligands are not identical and the C–O Ti distances ( d (C–O Ti ) avg = 1.277 Å, ranging from 1.252(4) Å to 1.297(5) Å) are fairly longer than the C–O K distances ( d (C–O K ) avg = 1.208 Å, ranging from 1.173(4) Å to 1.237(4) Å).…”

“…The signal at δ 5.80 ppm, which was assigned to be the two titanium bridging formato ligand from its integral value, appears at a significantly higher field 10 b compared to that of other reported formate bridged dititanium complexes. 9,11,12…”

Fast-Tracking the l-Lactide Polymerization Activity of Group 4 Metal Complexes of Amine Tris(phenolate) Ligands

“…Group 4 complexes of amine tris­(phenolate) ligands were first reported in 2001 and were found to catalyze various transformations, including ethylene polymerization, sulfoxidation, and, most relevant to this work, ROP of lactones. , The activities and the stereoselectivities of these complexes were found to depend on the metal and on the phenolate substituents. For example, the zirconium complex of the amine tris­(phenolate) ligand bearing bulky ortho - tert -butyl phenolate substituents was 7 times more active toward rac -LA than toward L-LA and led to highly heterotactic PLA in molten rac -LA polymerization at 130 °C, while the corresponding titanium complex was less active and non-stereoselective .…”

DFT Investigation of the η6 ⇌ η6-Inter-ring Haptotropic Rearrangement of the Group 8 Metals Complexes [(graphene)MCp]+ (M = Fe, Ru, Os)

“…Transition metal complexes are well-known for their catalytic applications in the design of novel derivatives and technological precursors (e.g., for polymers) or advantageous materials for various areas of science and industry such as sensors, catalysts, etc. − Catalytic properties of (MCp) + complexes of polyaromatic hydrogenated hydrocarbons are mainly associated with their structural peculiarities along with their capacity for inter-ring haptotropic rearrangements (IRHRs) that occur usually via intramolecular mechanisms. , IRHRs consist of the shifting of the ML n organometallic group (OMG) along the PAH plane, from one six-membered ring to another. In the course of such rearrangements, the metal center acquires unsaturation and therefore can easily coordinate additional species of substrates and/or reagents, thus giving rise to various potential chemical processes.…”