ISSN:
0009-2940
Keywords:
Ether phosphanes
;
Osmium(II) complexes
;
Conversion
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
η1-P- and η2-OP-Bonded (Ether-Phosphane)Osmium(II) Complexes and their Mutual ConversionReactions of cis-Br2Os(CO)4 with the (ether-phosphane) ligands 2a-f results in the formation of the cis,cis,trans-complexes Br2Os(CO)2(P ∼ O)2 (3a-f). 3b crystallizes in the mono-clinic space group P21/c with Z = 4. Irradiation of 3a-f leads to the cleavage of a further CO group and the formation of an Os—O bond to give the mono(chelate) complexes Br2Os(CO)-(PO) PO (5a-f), with one of the O,P ligands being bidentate. 5a-f exist as mixtures of different trans-P (A,B) and cis-P isomers (C-G). Dependent on the fact that a reversible cis/trans equilibrium or an irreversible trans → cis transformation is possible or that no trans-P isomers are present at any temperature, 5a-f may be classified in three categories. Inter-conversion of the isomers A-G results from dissociation of the η1-P coordinated ether-phosphane and concomitant occurrence of the 16e- species Br2Os(CO)(PO) (8). From temperature-dependent 31P{1H}-NMR spectroscopic investigations the temperature for the reversible opening of the metal-oxygen contact is determined. The reversible opening leads to the complexes Br2Os(CO)(PO)2 (9) with a vacant coordination site depending on the Os-O bonding strength. 5a-f react with CO to give all-trans-Br2Os(CO)2(PO)2 (4a-f). The action of the ether-phosphanes 2a-f on OsBr2(PPh3)4 (7) affords the bis(chelate) complexes Br2Os(PO)2 (6a-f) which add carbon monoxide to form all-trans-4a-f.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19921250303
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