The electronic structure of organometallic complexes of the f elements

Electronic Structure of Organometallic Complexes of f Elements. Are Molecular Orbital Calculations a Useful Tool for Spectroscopists?

“…At very low temperatures this compound exhibits temperature independent paramagnetism, thus indicating a nonmagnetic singlet CF ground state. The observed low intensities of the absorption transition which starts at the CF ground state and terminates at Γ1 ( 3Ρ0), and of the corresponding inverse luminescence transition are consistent with a CF ground state of Γ1 symmetry [12]. Applying the selection rules for forced electric dipole transitions [17][18][19] to the observed low temperature absorption and MCD spectra, respectively a couple of excited CF states of Γ4 and Γ6 symmetry could be identified and associated with their dominant component of ±Jz in the eigenvector.…”

“…Detailed analyses of the magnetochemical and optical properties of pseudo(ψ)--trigonal planar (Me3SiCp)3Ρr, ψ-trigonal pyramidal (C5 ^la)3Ρr.NCCIl3 ι ψ-trigo nal bipyramidal Cp3La(NCCH3)2:Pr, and ψ-trigonal pyramidal Ρr[N(SiMe3)2]3 have shown that the wave functions of the CF ground states of all these compounds are approximately described by Jz = 0 [12][13][14][15]. The CF state of Γ1 symmetry which arises from 3P0 is also described by Jz = 0 [16].…”

Crystal Field Strengths, Nephelauxetic Effects, and Experimentally Based Molecular Orbital Schemes (in the f Range) of Selected Cyclopentadienyl Complexes of Samarium(III)

“…Those of adducts 3؊5 are not given because of the close similarity of the CF splitting patterns of these compounds and [Sm(Cp) 3 (NCCH 3 )]. [45] Inserting the CF parameters of compounds 1؊5 into the relation below [2] were found, [7,48] (Table 3) which is mainly due to the decreasing absolute value of B 0 2 within this series. The results [49] of basic model calculations in the framework of the angular overlap model [50Ϫ52] are consistent with the found trend for the above mentioned compounds ( Table 3 .…”

“…In order to get a first idea of the signs and magnitudes of the CF parameters of complexes 1 and 2, we adopted the CF parameter set of ψ trigonal planar [Pr(C 5 H 4 SiMe 3 ) 3 ] [7] for 1, and for 2, we divided the CF parameters B 0 2 , B 0 4 and B 0 6 of this compound by three. Because of the similarity of the optical spectra of [Sm(Cp) 3 (NCCH 3 )] [45] and those of adducts 3؊5, we used the unchanged CF parameters of [Sm(Cp) 3 (NCCH 3 )] [45] as a starting set for the latter complexes.…”

“…[3Ϫ6] The individual CF strength associated with one single ligand L Ϫ of homoleptic neutral LnL 3 In recent years, we have parametrized the CF splitting patterns of a number of monomeric homoleptic LnL 3 [L ϭ C 5 H 4 SiMe 3 Ϫ , [7] N(SiMe 3 ) 2 Ϫ , [8Ϫ10] CH(SiMe 3 ) 2 Ϫ , [11,12] OC 6 H 3 tBu 2 -2,6 Ϫ [13] ] complexes and -using method Awe found enormous individual CF strengths. By combining these ligands L with those producing weak CF strengths, the individual CF strength of the ligand L may also be estimated by means of method B.…”