ISSN:
1434-1948
Keywords:
Tripodal P ligands
;
Rhodium
;
Water-soluble complexes
;
Immobilization
;
Biphasic hydroformylation
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The synthesis of the water-soluble tripodal phosphane ligand cis,cis-1,3,5-(PPh2)3-1,3,5-[CH2(OCH2CH2)xOCH3]C6H6 (x = 30-160) (5) has been achieved in a four-step reaction sequence. The alcohol Mo(CO)3[cis,cis-1,3,5-(PPh2)3-1,3,5-(CH2OH)3C6H6] (1) is converted to the corresponding alcoholate 2, which forms the polyethylene glycol derivative 3 in a polyaddition reaction with oxirane. After methylation of the end groups of 3, the ligand 5 is obtained by a combined photochemical/oxidative demolybdenation reaction. The water-soluble tripodal phosphane 5 and the methoxymethyl functionalized tripodal ligand 6 react with Rh(PPh3)3(CO)H to form the water-soluble and water-insoluble rhodium carbonyl hydrido complexes 5a and 6a, respectively. The catalytic activity of the rhodium complex 5a in the hydroformylation of 1-hexene was found to be comparable in a single-phase system (1-hexene/methanol) with that in the biphasic system (1-hexene/water). Only traces of alcohol were found, which demonstrates that the catalyst 5a displays higher selectivity in hydroformylation than in hydrogenation.
Type of Medium:
Electronic Resource
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