ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
Pentamethylcyclopentadienyl Transition Metal π-Complexes, VI1). Characterization and Reactions of the (Pentamethylcyclopentadienyl)cobalt(III) Moiety in WaterHalogeno Co(III) complexes [CoCp'X2]2, Cp' = η5-C5Me5, X = Cl, Br (2a, b) in water spontaneously and completely yield solutions of CoCp'-aquo cations. Spectroscopic, electrochemical, and potentiometric investigations indicate a mononuclear cation [CoCp'aq]2+ ([3a]2+) in acidic (pH 〈 5) and a dinuclear hydroxo-bridged cation [(CoCp')2(OH)3]+ ([7]+) amongst other species in alkaline (pH 〉 9) solution, where the latter precipitates as the tetraphenylborate salt. From the above aqueous solutions a variety of novel Co(III) complexes such as [CoCp'X2]2, X = NCS, N3 (10, 11), or [CoCp'LnX3-n](n-1)+, L = H2O, bipy, X, or X2 = acac, S2C2(CN)2, o-C6H4(NH)O, CoCp(PO(OEt)2)3, Cl, CN, NO2 (12 - 19), were precipitated or extracted. The longest wavelenght absorption in the visible spectrum of all these complexes follows the spectrochemical series.
Notes:
Die Halogenokomplexe [CoCp'X2]2, Cp' = η5-C5Me5, X = Cl, Br (2a, b), bilden in Wasser spontan CoCp'-aqua-Kationen. Spektroskopische, elektrochemische und potentiometrische Messungen sprechen für ein einkerniges Kation [CoCp'aq]2+ ([3a]2+) in saurer (pH 〈 5) und ein zweikerniges hydroxoverbrücktes Kation [(CoCp')2 (OH)3]+ ([7]+), fällbar als Tetraphenylborat, neben weiteren Komplexen in alkalischer (pH 〉 9) Lösung. Aus den wäßrigen Lösungen lassen sich eine größere Anzahl neuer Co(III)-Komplexe [CoCp'X2]2, X = NCS, N3 (10, 11) bzw. [CoCp'LnX3-n](n-1)+, L = H2O, bipy, X oder X2 = acac, S2C2(CN)2, o-C6H4(NH)O, CoCp(PO(OEt)2)3, Cl, CN, NO2 (12-19) fällen oder extrahieren. Die Lage der längstwelligen Absorptionsbande folgt in allen diesen Komplexen der spektrochemischen Reihe.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19841170228
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