Detailed nature of the six-coordinate polyhedra in tris(bidentate ligand) complexes

Abstract

consistent with a formal oxidation state of 4+ as proposed from Mossbauer spectra.1,9,10 The platinum 4f?/2 binding energies for both Pt8Sn2 cluster compounds fall well within the range of 72.4-73.9 eV reported by Riggs8 for 18 Pt compounds of oxidation state 2+. (This range does not overlap those of Pt complexes with oxidation states of 0 and 4+.) Thus, the platinum atoms in these clusters should be regarded as divalent rather than zerovalent if an assignment of oxidation state must be made. The assignment is quite arbitrary; a molecular orbital treatment of the cluster provides a better representation.11The platinum 4f?/2 binding energy of 73.2 eV for the [Pt(SnCl8)o]3~a nion12 likewise indicates an oxidation state of 2+ for the platinum and suggests that there is little accumulation of negative charge on the central metal atom. The similarity of Pt environments in this complex and in the cyclooctadiene complex is consistent with the postulate18 that the SnCl8 ligand is like an olefin in being able to accept electron density from a metal through x-bonds.Acknowledgment.-The author is deeply indebted to Dr. W. M. Riggs for determination of the spectra and for permission to quote his results prior to publication.(9) As pointed out by a reviewer, a correlation between Mossbauer chemical shifts and 4d binding energies has previously been noted.10 It is quite reasonable that a similar correlation with the 3d energies should exist.

Chelation versus Binucleation: Metal Complex Formation with the Hexadentate all‐cis‐N1,N2‐Bis(2,4,6‐trihydroxy‐3,5‐diaminocyclohexyl)ethane‐1,2‐diamine

“…For the other M(L e ) complexes, some twisting towards a trigonal prismatic form was noted. The twist angle f, describing the degree of distortion between a pure trigonal antiprismatic (f= 608) and a pure trigonal prismatic (f= 08) coordination geometry, [26] was 50.28 for the Ni complex 2, 48.98 for the Cu complex 3, and 48.68 for the Zn complex 4. This observation has to be related with the geometry of the diaminoethane bridge.…”

On the origin of circular dichroism in trigonal dihedral d6 complexes of bidentate ligands containing only σ‐orbitals. A qualitative model based on a density functional theory study of Λ‐[Co(en)3]3+

“…The rotation angle can be correlated to the polar ratio 39 (s/h of Fig. 2b), a measure of the polar displacement of the six nitrogens away from the ideal octahedron and the azimuthal angle 39 (/ of Fig.…”

“…2b), a measure of the polar displacement of the six nitrogens away from the ideal octahedron and the azimuthal angle 39 (/ of Fig. 2c), a parameter for the radial distortion of the six nitrogens away from the ideal octahedron, as:…”

A 12-Fold ThSi2 Interpenetrated Network Utilizing a Glycine-Based Pseudopeptidic Ligand

“…Additionally, in both ligands, the three amido groups exist in a trans conformation and all of them are in anti conformation ( Figure 3). Cu1 is coordinated to six atoms and exhibits a distorted octahedral geometry (s/h = 1.04, φ = 52.9 • [43]). The equatorial positions of this octahedron are occupied by four carboxylate oxygen atoms deriving from two different ligands.…”