ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Transition Metal Carbene Complexes, CXXVII. Kinetic and Mechanistic Investigations of Transition Metal Complex Reactions, XI11 2. Diethylamino(phenyltel1uro)carbene- and Diethylaminocarbyne(phenyltelluro) Complexes of Chromium: Preparative Investigations and Kinetics of the C, Cr-Migration of PhTePentacarbonyl(diethylaminocarbyne)chromium tetrafluoroborate, [(CO)5CrCNEt2]BF4 (1), reacts with lithium tellurophenolate, Li[TePh], with addition of the tellurophenolate anion to the carbyne carbon atom to give pentacarbonyl[diethylamino(phenyltelluro)carbene]chromium, (CO)5Cr[C(TePh)NEt2] (2). On heating in solution, the complex 2 rearranges with CO-elimination and C, Cr-migration of TePh to give trans-tetracarbonyl(diethylaminocarbyne)(phenyltelluro)chromium, trans-(PhTe)(CO)4CrCNEt2 (3). The rearrangement follows a first order rate law (-d[2]/dt = k[2]; ΔH≠ = 108 ± 1 kJmol-1; ΔS≠ = 42 ± 4 Jmol-1K-1; in 1,1,2-trichloroethane). In solution, 3 dimerizes with CO-elimination to give bis(μ-phenyltelluro)-bis[tricarbonyl(diethylaminocarbyne)chromium], (μ-PhTe)2[(CO)3CrCNEt2]2 (4). Addition of PPh3 to solutions of 2 does not influence the rate of the rearrangement but leads to a different product, mer-(PhTe)(CO)3(PPh3)CrCNEt2 (5).
Notes:
Pentacarbonyl(diethylaminocarbin)chrom-tetrafluoroborat, [(CO)5CrCNEt2]BF4 (1), reagiert mit Lithium-tellurophenolat, Li[TePh], unter Addition des Tellurophenolat-Anions an das Carbin-kohlenstoffatom und Bildung von Pentacarbonyl[diethylamino(phenyltelluro)carben]chrom, (CO)5Cr[C(TePh)NEt2] (2). Beim Erwärmen in Lösung lagert sich der Komplex 2 unter CO-Abspaltung und C, Cr-Wanderung von TePh nach einem Geschwindigkeitsgesetz erster Ordnung (-d[2]/dt = k[2]; ΔH≠ = 108 ± 1 kJmol-1; ΔS≠ = Jmol-1K-1; in 1,1,2-Trichlorethan) zu trans-Tetracarbonyl(diethylaminocarbin)(phenyltelluro)chrom, trans-(PhTe)(CO)4-CrCNEt2 (3), um. In Lösung dimerisiert 3 unter CO-Eliminierung zu Bis(μ-phenyltelluro)-bis[tricarbonyl(diethylaminocarbin)chrom], (μ-PhTe)2[(CO)3CrCNEt2]2 (4). Zusatz von PPh3 zu Lösungen von 2 beeinflußt zwar die Umlagerungsgeschwindigkeit nicht, liefert jedoch als Reaktionsprodukt mer-(PhTe)(CO)3(PPh3)CrCNEt2 (5).
Additional Material:
2 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19831160318
