Transition-metal binding sites and ligand parameters

Abstract

N3-Ligdnd constant, PL/V ( & 0.05 V cstimated error) + 1.46 1.40 0.00 -0.07 -0.10 -0.35 -0.38 -0.40 -0.4:) -0.58 -0.59 -0.77 -0.78 -0.88 -1.00 -1.16 -1.15 -1.17-1.19 -1.22 -1.26 -1.55measured and values which we have deduced by intcrpolation from data from other series of Complexes (see below). These ligand constants refer t o L as a twoelectron donor ligand which must be added t o the 16electron moiety to give the closed-shell 18-electron complexes [M,L], x bonding being ignored. Considered in this way the nitride ligand in [M,N] is formally N+, the nitrosyl NO+, and the hydride H-. From Table 1 it can be seen that charged ligands occupy the extremes of the scale. The weakest Q donors with strong x-acceptor

Synthesis, Characterization, Spectral Properties and Electrochemical of Compounds <i>trans</i>-[Ru(NH)<sub>3</sub>L(bpa)]<sup>2+</sup>

“…This increase is attributed to the π and σ interactions of ligand L with metal; thus, for ruthenium, unsaturated ligands stabilize the lowest oxidation state. Chatt et al [18] observe the effect of the ligands on the metal atom, similar to that observed for aromatic compounds using cyclic voltammetry. These studies show that the higher the reception capability of electrons π is allied to the smaller capacity σ of ligand L, the greater the value of the formal charge E f will be.…”

Estimate of Electrochemical Ligand Parameters in Iron(II) Adducts of [FeH(CN)(dppe)2]

“…By applying the previously reported [2] Es and 8 parameters for the iron site of this study {FeH(dppe)2} + (Es = 1.04, p = 1.0), it was possible to estimate the PL parameter for CN as well as for the cyano-derived ligands (Table), Another electrochemical parametrization approach was developed by Lever [4,5] who proposed a general redox potential-structure relationship expressed by eq. Alternatively, from the above PL values of the isocyanide ligands, one could also try to estimate the Lever EL values by taking into account the observed [4] overall linear relationship (except for carbon monoxide [4] and other strong it-electron acceptors such as carbynes [6]) between the two parameters [eq.…”

“…2) by the oxidation potential of its carbonyl complex [Ms(CO)] (the higher Es the lower the electron-richness), whereas p is a measure of the polarisability of the metal site [2]. PL is defined as the difference…”

“…The dissociation reaction produces adsorbed CO from the alcoholic group in addition to benzene from the aromatic ring. Partial and total hydrogenation compounds from benzene and toluene were detected simultaneously with the production of molecular hydrogen [2,3].…”

The Parameterisation of Metal Centred Redox Couples

“…A ligan parameter, PL was defined (10, 12,131 where, for example, v1.02 Sintra.doc march 15/92 --2--PL -Ev2(Cr(CO) 6 1 -EV2[Cr(CO) 5 L! (2) with some additional refinements to which the reader is referred [111.…”