On the structure of electrons in metal organic complexes of f-elements LI. Synthesis, crystal, molecular and electron structure of Cp3Nd(NCCH3)2
Cp(3)Nd(NCCH(3))(2) 1) crystallizes in the orthorhombic space group Pbcn with a = 13.961 2) A, b = 8.484 2) A, c = 14.840 2) A, Z = 4, R = 0.0359, Rw = 0.0408 for 1191 data and I > 3s(I). Like in the case of the La, Ce and Pr derivatives the Nd(3+) central ion of compound 1 is pseudo trigonal bipyramidally coordinated by three ?(5) -bonded Cp rings in the equatorial plane (Nd-ring centre distances 2.561 A, 2.554 A) and two acetonitrile groups in the axial positions (Nd-N = 2.764(5) A). The absorption spectra of extremely sensitive 1 (pellets), the much more stable optically diluted Cp(3)La(0.8)Nd(0.2)(NCCH(3)(2) (2) (Single crystals), CP(3)La(NCCH(3))(2) (3) (Single crystals) and Cp(3)NdNCCH(3) (4) (pellets) were recorded at room and low temperatures. From the spectra obtained, truncated crystal field splitting patterns of complexes 2 and 4 were derived, and simulated by fitting the parameters of an empirical Hamiltonian. For 56 and 55 assignments, respectively, reduced r.m.s. deviations of 32.3 cm(-1) and 20.9 cm(-1) are achieved for 2 and 4. From the parameters used the experimentally based non-relativistic and relativistic molecular orbital schemes in the f range are set up for 2 and 4. On the basis of the calculated wavefunctions and eigenvalues obtained from the fits, the spectroscopic splitting factors (extracted from the EPR spectrum) of 2 and the temperature dependence of Á(2 eff) of 1 and 4 can be explained. The existence of Cp(3)La(NCCH(3))(2):Tb (3+) (5) is proved by the luminescence spectrum of this complex.
Bibliographic Reference: An article published in: Elsevier Journal of Organometallic Chemistry 622 (2001) pp.19-32
Record Number: 200013540 / Last updated on: 2001-07-25
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