Transmetalation of Chromocene by Lithium-Amide, -Phosphide, and -Arsenide Nucleophiles

Scheuermayer, Sabine and Tuna, Floriana and Pineda, Eufemio Moreno and Bodensteiner, Michael and Scheer, Manfred and Layfield, Richard A. (2013) Transmetalation of Chromocene by Lithium-Amide, -Phosphide, and -Arsenide Nucleophiles. INORGANIC CHEMISTRY, 52 (7). pp. 3878-3883. ISSN 0020-1669,

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Abstract

The pnictogen-centered nucleophiles LIE(SiMe3)(2) (E = N, P, or As) substitute a cyclopentadienide ligand of chromocene (Cp2Cr), with elimination of lithium cyclopentadienide, to give the series of pnictogen-bridged compounds [(mu:eta(2):eta(5)-Cp)Cr{mu-N(SiMe3)(2)}(2)Li] (1) and [(eta(5)-Cp)Cr{mu-E(SiMe3)(2)}](2), with E = P (2) or E = As (3). Whereas 1 is a heterobimetallic coordination polymer, 2 and 3 are homometallic dimers, with the differences being due to a structure-directing influence of the hard or soft character of the bridging group 15 atoms. For compound 1, the experimental magnetic susceptibility data were accurately reproduced by a single-ion model based on high-spin chromium(II) (S = 2), which gave a g-value of 1.93 and an axial zero-field splitting parameter of D = 1.83 cm(-1). Determinations of phosphorus- and arsenic-mediated magnetic exchange coupling constants, J, are rare: in the dimers 2 and 3, variable-temperature magnetic susceptibility measurements identified strong antiferromagnetic exchange between the chromium(II) centers, which was modeled using the spin Hamiltonian H = -2J (S-Cra.S-CrB), and produced large coupling constants of J = -166 cm(-1) for 2 and -77.5 cm(-1) for 3.

Item Type: Article
Uncontrolled Keywords: CRYSTAL-STRUCTURES; SPIN-CROSSOVER; COMPLEX; CHROMIUM(II); LIGANDS; DIMERS; SPECTROSCOPY; PHOSPHORUS; REACTIVITY; CHEMISTRY;
Subjects: 500 Science > 540 Chemistry & allied sciences
Divisions: Chemistry and Pharmacy > Institut für Anorganische Chemie > Chair Prof. Dr. Manfred Scheer
Depositing User: Dr. Gernot Deinzer
Date Deposited: 17 Apr 2020 09:25
Last Modified: 17 Apr 2020 09:25
URI: https://pred.uni-regensburg.de/id/eprint/16893

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