Spin-Orbit Coupling in Tetragonal d³ Systems

Abstract

The complete set of energy matrices for tetragonal d 3 systems, including spin-orbit coupling, has been constructed within the framework of the Angular Overlap Model. Examples are presented of the variation in energy of the intraconfigurational (t\t) doublets as a function of spinorbit coupling (appropriate to first row metal ions) and ligand field asymmetry. It is seen that asymmetry in Dq values is much less important than the relative partitioning of Dq into ea and en • The use of spin-orbit matrix elements in the calculation of intensities of spin-forbidden transitions is also illustrated.

Synthesis and Characterizations of Macrocyclic Cr(III) and Co(III) 1-Ethynyl Naphthalene and 9-Ethynyl Anthracene Complexes: An Investigation of Structural and Spectroscopic Properties

“…The assignment of the emission as a 2 T 1g → 4 A 2g ( O h ) transition is consistent with previous studies of related complexes, ,, and partially based on the significant red shift in the peak position compared to where 2 E g emissions have been observed . Such a shift is representative of a difference in the donating/withdrawing behavior of the ligands, where the equatorial tetraazamacrocycle is σ-donating and the apical alkynyls are both σ- and π-donating toward the electron deficient Cr­(III) metal center . Compiled in Table are relevant emission parameters and results.…”

“…62 Such a shift is representative of a difference in the donating/withdrawing behavior of the ligands, where the equatorial tetraazamacrocycle is σ-donating and the apical alkynyls are both σand π-donating toward the electron deficient Cr(III) metal center. 63 Compiled in Table 2 are relevant emission parameters and results. The phosphorescences of both [1] + and [2] + show fine structuring at 77 K but not room temperature.…”

Synthesis of cis and trans Bis-alkynyl Complexes of Cr(III) and Rh(III) Supported by a Tetradentate Macrocyclic Amine: A Spectroscopic Investigation of the M(III)–Alkynyl Interaction

“…Typical 2 T 1g emitters of similar structure (e.g., trans -[Cr(cyclam)(OH) 2 ] + and trans -[Cr(tet a)F 2 ] + where tet a is C-meso- 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) can be characterized as having axial ligands that are both σ and π donors . However, assignment of the emission as originating from the 2 T 1g excited state does not necessitate that the ligands be π-donors but only that there exists an asymmetry of π effects (π-donating or π-withdrawing) between the axial and equatorial ligands . Regardless, the vibrational data discussed above clearly point toward the asymmetry arising from π-donation from the alkynyl ligand.…”

Emissive Chromium(III) Complexes with Substituted Arylethynyl Ligands

“…23 Assignment of the emission as originating from the 2 T 1g excited state only reflects an asymmetry of π effects (π-donating or π-withdrawing) between the axial and equatorial ligands. 24 However, the Raman data and literature precedence 5,19 would suggest that these arylethynyl ligands are acting as π donors toward the electron-poor chromium(III). The excited-state lifetimes of these complexes are solvent-dependent and also sensitive to the presence of oxygen (Table 1).…”