Effective donor abilities of E-t-Bu and EPh (E = O, S, Se, Te) to a high valent transition metal

Abstract

Amido rotation in the chromium(vi), d(0)-system NCr(NPr(i)2)2X is under investigation as a method for the parameterization of ligands for their donor properties toward high valent metals. In this study, two new series were prepared and studied based on chalcogenide ligands, X = EBu(t) and EPh and where E = O, S, Se, Te; the OPh and SPh compounds were previously reported. The ligand donor parameters for these ligands correlate with the Cr-E-C angles in these chalcogenide series. In addition, it was found that NBO calculated overlaps and DFT calculated bond dissociation enthalpies correlate within X = halide-, EBu(t)- and EPh-series. All of the new complexes were characterized by X-ray diffraction.

A full set of iridium(iv) pyridine-alkoxide stereoisomers: highly geometry-dependent redox properties

“…First, the ligand donor strengths are ordered N < Cl < O, based on our data as well as ligand parameters. 19,20,24,25 The d orbital that experiences the greatest net ligand donation becomes the HOMO that gives the oxidation enhancement effect; Table 2 shows the resulting pattern.…”

“…This ligand was designed to incorporate a number of relevant properties. First, it contains a highly σ and π electron-donating alkoxide arm, 19,20 which not only allows it to stabilize high oxidation states, but also enhances water solubility and permits reversible protonation and hydrogen bonding. Second, this alkoxide is protected from oxidative degradation by the geminal dimethyl substitution, allowing it to survive the harsh reaction conditions required for water oxidation or formation of high-valent metal complexes.…”

“…Simple treatments, such as Lever parametrization, 19,20,24–26 cannot account for differences due to isomerism. This geometry effect was indeed noted by Lever, 24 but only for strong acceptor ligands (CO, NO + ).…”

Reactivity of a Monomeric Aluminium Hydrazide towards Isocyanates and Isothiocyanates: Active Lewis Pair Behaviour versus Classical Insertion Reactions

“…The phenyl group is not coplanar with these atoms and seems not to contribute to delocalisation by a mesomeric interaction (angle between the normals of the planes Al1S1C3N3 and phenyl: 67.1°). The C3–S1 distance [189.0(2) pm] is in the upper range of those of C–S single bonds in thiolate or thioether complexes . The nitrogen atoms N3, bound to phenyl, and N1 of the hydrazide group have a planar coordination sphere, while N2 has a trigonal‐pyramidal environment (sum of angles: 342.2°), and its lone pair of electrons is not involved in the delocalised electronic system.…”

Systematic evaluation of the electronic effect of aluminum-containing ligands in iridium–aluminum and rhodium–aluminum bimetallic complexes

“…This has the potential to be very powerful, as electron donor parameters exist for a large number of organic ligands. [45][46][47] When designing ligands for eventual catalytic applications we can use these tabulated data as a proxy for the aluminum-containing ligands desired. Alternatively, we can calculate the donor ability of the bridging ligand using our Vaska's complex framework and extrapolate.…”