Electronic structures of organometallic complexes of f elements LXVI

Electronic structures of organometallic complexes of f elements LXXIX: Truncated crystal field splitting patterns of monomeric pseudo trigonal planar Yb(η5-C5H4R)3 (R = Me, Et, tBu, SiMe3) complexes and polymeric [(η5-C5H5)2Yb(μ-η5:η1-C5H5)] as well as selected mono adducts

“…The B 2 0 value of À3529 cm À1 is even more negative than those of the likewise quasi trigonal planar complexes Yb[N(SiMe 3 ) 2 ] 3 (À2592 cm À1 [43]) and Sm(C 5 Me 4 H) 3 (À2971 cm À1 [45]). …”

Electronic structures of organometallic complexes of f elements LXXV

“…However, this general trend does not hold for the Slater parameter F 2 and the spin-orbit coupling parameter z 4f . Sm(C 5 Me 4 H) 3 [7] shows higher F 2 and z 4f values than SmCp * 3 [10], whereas the pair of compounds Pr(C 5 Me 4 H) 3 /PrCp * 3 exhibits the opposite effects [3,9]. It is the main aim of this paper to find out whether the pair 2/1 follows the trend of the corresponding Sm or Pr compound pairs.…”

“…The absorption spectra of each Ln(C 5 Me 4 H) 3 /LnCp * 3 (Ln ¼ Ce [2,8], Pr [3,9], Sm [7,10]) complex pair with the same Ln 3þ central ion (both KBr pellets) are not too different. Thus, by comparing those of NdCp * 3 (1) with those of Nd(C 5 Me 4 H) 3 (2) (previously partly assigned on the basis of LD, LA, and electronic Raman measurements of oriented single crystals [4e6]) the CF splitting pattern of compound 1 can be determined.…”

“…In recent years, the electronic structures of pseudo (j) trigonalplanar Ln(C 5 Me 4 H) 3 (Ln ¼ Ce [2], Pr [3], Nd [4e6], Sm [7]) and LnCp * 3 (Ln ¼ Ce [8], Pr [9], Sm [10]; Cp * ¼ h 5 -C 5 Me 5 ) complexes have been the targets of a number of crystal field (CF) analyses. The latter class of compounds is difficult to synthesize [11e16] and as yet, only small single crystals could be grown, which allowed (besides X-ray diffraction work, which found the space group P6 3 /m, with two molecules of somewhat distorted D 3h symmetry in the unit cell [11e14, 16], see Fig. SI-1) only luminescence anisotropy [17] (LA) and Raman spectroscopic (both vibrational [18] and electronic [19] polarization measurements [9,10].…”

“…The analyses of the CF splitting patterns of Ln(C 5 Me 4 H) 3 and LnCp * 3 complexes (Ln ¼ (Ln ¼ Ce [2,8], Pr [3,9], Sm [7,10]) showed that the CF strengths [23] experienced by the central Ln 3þ ions of the former class of compounds are stronger than those of the latter. This finding may be easily explained by the shorter LneC distances of the Ln(C 5 Me 4 H) 3 [24e26] complexes compared to those of the corresponding LnCp * 3 compounds [11e14, 16].…”