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Zur Elektronenstruktur metallorganischer Komplexe der f‐Elemente. 68 Absorptions‐ sowie erstmalige lumineszenz‐ und Raman‐spektroskopische Polarisationsmessungen an einem orientierten metallorganischen Einkristall: Pr(C 5 Me 4 H) 3
Author(s) -
Amberger HannsDieter,
Reddmann Hauke
Publication year - 2008
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200800101
Subject(s) - chemistry , raman spectroscopy , spectrochemical series , single crystal , crystallography , absorption spectroscopy , ion , ligand field theory , physics , organic chemistry , quantum mechanics , optics
Electronic Structures of Organometallic Complexes of f Elements. 68 Absorption and First Luminescence and Raman Spectroscopic Polarization Measurements of an Oriented Organometallic Single Crystal: Pr(C 5 Me 4 H) 3 Optical polarization measurements of oriented single crystals of Pr(C 5 Me 4 H) 3 ( 1 ) were performed at room temperature. In order to separate “cold” and “hot” f‐f‐transitions and νC–H combination vibrations, the absorption spectra of KBr pellets of compound 1 and La(C 5 Me 4 H) 3 ( 2 ) were additionally recorded at ca. 77 K. To gather additional information about the wavefunctions of the crystal field (CF) states of complex 1 , a magnetic circular dichroism spectrum of 1 was recorded too. From the spectra obtained, a partial CF splitting pattern of 1 was derived, and simulated by fitting the free parameters of a phenomenological Hamiltonian, leading to a reduced r.m.s. deviation of 24.8 cm −1 for 24 assignments. On the basis of these phenomenological CF parameters, the global CF strength experienced by the Pr 3+ central ion was estimated, and seems to be the largest one ever encountered in Pr III chemistry. The obtained Slater parameter F 2 and the spin‐orbit coupling parameter ζ 4f allow the insertion of compound 1 into empirical nephelauxetic and relativistic nephelauxetic series, respectively, of Pr III compounds. With its low F 2 value, complex 1 is the most covalent Pr III compound (considering only f electrons) found to date. The experimentally‐based non‐relativistic molecular orbital scheme (in the f range) of complex 1 was determined and compared with the results of a previous Xα‐SW calculation on the ψ trigonal planar model compound Pr(η 5 ‐C 5 H 5 ) 3 . In the framework of the search for “polarized” luminescence transitions, polarized Raman spectra of 1 were recorded too, and compared to the corresponding FIR and IR spectra run by means of pellets.