ISSN:
0044-2313
Keywords:
Dirhenium complex anion
;
rheniummolybdenum complex anion
;
NMR data
;
crystal structure
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Insertion of a Terminal Halogeno Ligand into Diorgano-bridged Dirhenium and Rhenium-Molybdenum Complex Anions in the Presence of an Amidin Cation and the Isomerization ProcessesThe equimolar reaction of in situ generated anion Anions Re2(μ-PCy2)(CO)8- (Re—Re) in the presence of a steric expansive amidine cation DBUH+ with bromine and iodine in tetrahydrofuran solution gave the two isomers Re2(PCy2)(CO)8X (Re—Re) and Re2(μ-PCy2)(μ-X)(CO)8 (X = Br, I), of which the isomer with a terminal X ligand as major product was formed under maintenance of the Re—Re bond. The monotropic isomerization process of Re2(μ-PCy2)(CO)8I runs thermically relative slowly, but more rapid in photochemical and electrochemical processes. The analogeous reaction of the heterometallic anion ReMo(η5-C5H5)(μ-PPh2)(CO)6- with iodine delivers opposite to the former reaction mainly the bridged isomer ReMo(η5-C5H5)(μ-PPh2μ-I)(CO)6 besides ReMo(η5-C5H5)(μ-PPh2)(CO)6I. The obtained complexes were characterized by means of v(CO) and 31P NMR spectroscopic measurements. Single-crystal analyses led to the subsequent metal - metal bond lengths: Re—Re of 308.0(1) pm in Re2(μ-PCy2)(CO)8Br and Re—Mo of 313.6(1) pm in ReMo(η5-C5H5)(μ-PPh2)(CO)6I.
Notes:
Die äquimolare Umsetzung des in situ gebildeten Anions Re2(μ-PCy2)(CO)8 (Re—Re) in Gegenwart eines sterisch anspruchsvollen Amidinkations DBUH+ mit Brom und Jod in Tetrahydrofuranlösung bei 20°C ergab jeweils von beiden Isomeren Re2(μ-PCy2)(CO)8X (Re—Re) und Re2(μ-PCy2)(μ-X)(CO)8 (X = Br, I) überwiegend dasjenige mit terminal gebundenem Halogenoliganden unter Aufrechterhaltung der Re—Re-Bindung. Die monotrope Isomerisierung von Re2(μ-PCy2)(CO)8I verläuft thermisch relativ langsam, aber photochemisch und elektrochemisch schneller. Die analoge Umsetzung des heterometallischen Anions ReMo(η5-C5H5)(μ-PPh2)(CO)6 mit Jod lieferte demgegenüber bevorzugt das verbrückte Isomer ReMo(η5-C5H5)(μ-PPh2)(μ-I)(CO)6 neben ReMo(η5-C5H5)(μ-PPh2)(CO)6I. Die erhaltenen Komplexe wurden durch v(CO)- und 31P NMR-spektroskopische Daten charakterisiert. Einkristall-Röntgenstrukturanalysen führten zu folgenden Metall - Metall-Bindungslängen: Re—Re von 308,0(1) pm in Re2(μ-PCy2)(CO)8Br und Re—Mo von 313,6(1) pm in ReMo(η5-C5H5)(μ-PPh2)(CO)6I.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/zaac.19946200927
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