ISSN:
0009-2940
Keywords:
Lewis acids, organometallic
;
12-e- Systems
;
Alkyne complexes
;
Molybdenum complexes
;
Tungsten complexes
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Organometallic Lewis Acids, LIV. - Mo(CO)2(PPh3)2(O3SCF3)2: A New Precursor for an Organometallic Dicationic Lewis Acid with Three Accessible Coordination SitesThe reaction of Mo(CO)2(PPh3)2Br2 (1) with AgO3SCF3 gives the bis(triflate) complex Mo(CO)2(PPh3)2(O3SCF3)2 (3) which can be considered as a precursor for the 12-e- system “Mo-(CO)2(PPh3)2+2”. According to the spectroscopic data one of the two coordinated CF3SO-3 anions is acting as a chelate ligand. Treatment of 3 and of the in situ generated W(CO)2(PPh3)2(O3SCF3)2 (4) with H2O affords the dinuclear hydroxo-bridged complexes [M2(μ-OH)3(CO)4(PPh3)4][CF3SO3] (5: M = Mo; 6: M = W). Acetonitrile replaces the CF3SO-3 ligands in 3 and 4 to afford the cationic complexes [M(CO)2(PPh3)2(NCMe)3][CF3SO3]2 (7: M = Mo; 8: M = W). The reaction of 3 with an excess of 2-butyne and 1-phenyl-1-propyne leads to the monoalkyne complexes Mo(CO)(MeC≡CR)(PPh3)2(O3SCF3)2 (9: R = Me; 10: R = Ph) in moderate yield. In contrast, the bisalkyne complexes [M(CO)(MeC≡CMe)2(PPh3)2(O3SCF3)][CF3SO3] (11: M = Mo; 12: M = W) are formed in high yield when a CH2Cl2 solution of 2-butyne is added to 1 and 2 in the presence of AgO3SCF3. At room temperature, 11 and 12 are highly fluxional in solution, while 9 and 10 are stereochemically rigid. Treatment of 11 with acetonitrile yields [Mo(CO)(MeC≡CMe)2(PPh3)2(NCMe)][CF3SO3]2 (13). Compounds 3-13 (except 4) are characterized by IR, 1H-, 13C-, 19F-, and 31P-NMR spectrescopy.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19951280712
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