Universität zu Köln

Moossen, Oliver and Dolg, Michael ORCID: 0000-0002-0538-0837 (2015). Multi-reference character and Ce 4f orbital contributions in terminal multiple Ce-Z bonds of Cp(2)CeZ (Z = CH2, CH-, NH, O, F+) complexes. Comput. Theor. Chem., 1073. S. 34 - 45. AMSTERDAM: ELSEVIER SCIENCE BV. ISSN 1872-7999

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Abstract

The geometric and electronic structures of bis(cyclopentadienyl)cerium compounds of the type Cp(2)CeZ (Z = CH2, CH-, NH, O, F+) are analyzed paying special attention to the terminal metal-ligand multiple bonding in the Ce-Z units. Complete active space self-consistent field calculations were performed, followed by unitary transformations in the active orbital space in order to monitor the weights of the leading configurations, as well as the Ce and Z character of the orbitals. It is shown that all compounds, except the closed-shell Ce(IV) complex Cp2CeF+, have an open-shell singlet ground state and the 4f orbitals are important for their electronic structure. In case of Z = CH2, CH- the singlet ground state consists to more than 90% of the Cef(pi)(1)Zp(pi)(1) configuration when using nearly pure cerium 4f and carbon 2p orbitals of the Z group, implying Ce(III) systems. In contrast, the systems containing Z = NH, O revealed a more mixed Ce(III)/Ce(IV) ground state wavefunction. The interactions of the active orbitals were characterized by calculating the expectation values of the charge fluctuation operator and the local spin operator. The results are evaluated by comparison with the values achieved by stretching the covalent bond of a H-2 molecule. The CH2 and the CH- complexes show, besides a Ce-Z a bond, a quite weak covalent Cef-Z p orbital interaction in It symmetry, while the other two complexes (Z = NH, O) exhibit a stronger covalent interaction with a noticeable ionic character because of the higher electronegativities of nitrogen and oxygen. (C) 2015 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Moossen, Oliver UNSPECIFIED UNSPECIFIED UNSPECIFIED Dolg, Michael UNSPECIFIED orcid.org/0000-0002-0538-0837 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-385669
DOI:	10.1016/j.comptc.2015.09.013
Journal or Publication Title:	Comput. Theor. Chem.
Volume:	1073
Page Range:	S. 34 - 45
Date:	2015
Publisher:	ELSEVIER SCIENCE BV
Place of Publication:	AMSTERDAM
ISSN:	1872-7999
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Theoretical Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ZETA VALENCE QUALITY; BASIS-SETS; OXIDATION-STATE; CONFIGURATION-INTERACTION; ELECTRONIC-STRUCTURES; GROUND-STATE; CEROCENE; TH; SPECTROSCOPY; COVALENCY Multiple languages Chemistry, Physical Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/38566