Three-co-ordinated transition-metal compounds. Part II. Electronic spectra and magnetism of tris(bistrimethylsilylamido)derivatives of scandium, titanium, vanadium, chromium, and iron

Abstract

The electronic spectra, magnetic susceptibilities, and preliminary e.s.r. data are reported for the trigonal compounds M[N(SiMe,),],where M = Sc,Ti, V, Cr,and Fe. The data are interpreted on the basis of crystal-field calculations for d" systems in D3, symmetry.

Photochemistry of tris(pyrazolyl)borate titanium(IV) complexes

“…Accepting these considerations, and on the basis of the experimental values of D and f, we can only postulate a pseudo-octahedral structure in solution for the TpTi(III)Cl 2 (THF) and Tp*Ti(III)Cl 2 (THF) complexes. The observed transitions and the calculated values of f are in good agreement with those reported for related compounds of know structure [16].…”

Local Structures and Heterogeneity of Silica-Supported M(III) Sites Evidenced by EPR, IR, NMR, and Luminescence Spectroscopies

“…X-ray near-edge absorption spectroscopy (XANES) at the Cr K-edge of 1-Cr , 1-Cr/SiO 2 , and 1-Cr@SiO 2 reveals spectra with almost identical edge energies which indicate the conservation of the oxidation state +3 in all three species (Figure a). , The spectrum of 1-Cr displays pre-edge features at 5989.1 and 5991.2 eV (1s to 3d transitions) and a near-edge feature at 5995.0 eV (1s to 4p transition). The pre-edge feature at 5989.1 eV can be assigned to transitions to the molecular orbitals with mainly metal d character of e″ and a′ 1 symmetry of D 3 h symmetry, while the pre-edge feature at 5991.2 eV probably corresponds to transitions to the molecular orbitals of e′ symmetry, consistent with UV–vis absorption spectrum of 1-Cr , which shows an absorption maximum at 685 nm (ESI Figure S2). Similar pre-edge and near-edge features at 5989.5, 5991.3, and 5995.0 eV are present in the spectrum of 1-Cr/SiO 2 , though weaker in intensity.…”

Large Easy‐Plane Magnetic Anisotropy in a Three‐Coordinate Cobalt(II) Complex [Li(THF)4][Co(NPh2)3]

“…It should be noted that the ground state of the free Co 2 + ion is 4 F 9/2 ,w hich splits into 4 A 2 ' + ( 4 A 1 '', 4 A 2 '') + 4 E'' + 4 E' in D 3h ligand field. [17] For 1,a st he local coordination symmetry of the Co II ion is close to D 3h the singlet 4 A 2 ' would be the ground state. With this non-degenerate ground state the first-order or-bital momentum is thus quenched.…”