Sophia R. Su

Studies on substitution, insertion and decarbonylation reactions of some cyclopentadienyliron complexes with phosphorus donor ligands

Abstract The phosphite complexes C 5 H 5 Fe(CO)[P(OR) 3 ]CH 3 (R=CH 3 , n-C4H9 or C 6 H 5 ) have been synthesized by the interaction of C 5 H 5 Fe(CO)[P(C 6 H 5 ) 3 ]CH 3 with P(OR) 3 in tetrahydrofuran at reflux. They react readily with liquid SO2 to afford the corresponding S-sulfinates, C 5 H 5 Fe(CO)[P(OR) 3 ](SO2CH 3 ). The reaction between C 5 H 5 Fe(CO)2CH 3 and P(C 6 H 5 ) 3 in hydrocarbon solvents at reflux yields initially C 5 H 5 Fe(CO)[P(C 6 H 5 ) 3 ](COCH 3 ), which then undergoes decarbonylation to C 5 H 5 Fe(CO)[P(C 6 H 5 ) 3 ]CH 3 . However, in refluxing dioxane, C 5 H 5 Fe(CO) [P(C 6 Hs) 3 ] (COCH 3 ) has been obtained as the only major carbonyl product. The corresponding dicarbonyl ethyl complex, C 5 H 5 Fe(CO)2C2H 5 , reacts with P(C 6 H 5 ) 3 in heptane at reflux to give C 5 H 5 Fe(CO)[P(C 6 Hs) 3 ] (COC2H 5 ) and C 5 H 5 Fe(CO) [P(C 6 H 5 ) 3 ] Cl. The chloride has been shown to arise from the reaction of CHCI 3 with C 5 H 5 Fe(CO)[P(C 6 H 5 ) 3 ]H, which results from loss of ethylene by C 5 H 5 Fe(CO)[P(C 6 H 5 ) 3 ]C2H 5 . Photochemical reactions between C 5 H 5 Fe(CO)2C2H 5 and P(C 6 H 5 ) 3 in petroleum ether yield C 5 H 5 Fe(CO)[P(C 6 H 5 ) 3 ]C2H 5 directly, without the intermediacy of C 5 H 5 Fe(CO)[P(C 6 H 5 ) 3 ] (COC2H 5 ). Contrary to a previous report, ultraviolet irradiation of C 5 H 5 Fe(CO)[P(C 6 H 6 ) 3 ](COR) (R = CH 3 or C 5 H 5 ) in hydrocarbon solvents under several different conditions affords the corresponding C 5 H 5 Fe(CO)[P(C 6 H 5 ) 3 ]R in moderate to good yields.

REACTIONS OF CYCLOPENTADIENYLMETAL‐2‐ALKENYL CARBONYL COMPLEXES WITH SULFUR DIOXIDE. ISOLATION AND CHARACTERIZATION OF 2‐ALKENE‐S‐SULFINATO PRODUCTS

Abstract Transition metal 2-aIkenyl complexes η5-C5H5Fe(CO)2CH2C(R)CR′R″ (R, R′ and R″ = H and/or CH3) and η5-C5H5Mo(CO)3CH2CHCH2 react rapidly with liquid SO2 at −10 °C or below to afford the corresponding zwitterions, η5-C5H5Fe+(CO)2(η2CH2C(R)C(R′)(R″)SO−2) and η5C5H5Mo+(CO)3(η2-CH2CHCH2SO−2) respectively. There zwitterions were characterized by infrared and 1H NMR spectroscopy and, in the case of η5-C5H5Fe+(CO)2(η2-CH2CHCH2SO−2), also by conductivity measurements and alkylation with (CH3)3OBF4 and (C6H5)3CCl to give [η5-C5H5(CO)2(η2-CH2CHCH2S(O)2R]+X− (R = CH3 and (C6H5)3C) Upon storage in liquid SO2 the zwitterions were found by infrared and 1H NMR spectroscopy to rearrange to the corresponding S-sulfinato complexes in the approximate order η5-C5H5Fe+(CO)2(η2-CH2CHC(CH3)2SO−2) ⩾ η5-C5H5Fe+(CO)2(η2-CH2C(CH3)CH2SO−2) > η5C5H5Fe+(CO)2(η2-CH2CHCH(CH3)SO−2) > η5-C5H5Fe+(CO)2(η2-CH2CHCH2SO−2) and η5-C5H5Mo+(CO)3(η2-CH2CHCH2SO−2) > η5-C5H5Fe+(CO)2(η2-CH2CHCH2SO−2). The rearrangement of η5-C5H5Fe+(CO)2(η2-CH2CHCH2SO−2) to the S-sulfinate η5-C5H5Fe(CO)2S(O)2CH2CHCH2 occurs concomitantly with the formation of a cycloaddition product, formulated at η5-C5H5Fe(CO)2 CHCH 2 S(O)2C H2. This cycloadduct is unstable toward dimerization and/or trimerization, especially in solution, yielding a readily isolable [η5-C5H5Fe(CO)2(C3H5SO2)]2 or 3. The molybdenum zwitterion η5-C5H5Mo+(CO)3(η2CH2CHCH2SO−2) displays a parallel behavior in rearrangement. Various factors that affect the formation of these products and possible mechanisms of these reactions are presented and discussed.

Synthesis of a transition metal-dithionite complex, (η5-C5H5)(CO)2FeS(O)2S(O)2Fe(CO)2(η5-C5H5)

Abstract The reaction of Na[η5-C5H5Fe(CO)2] with large excess of SO2 in THF at −78°C followed by warming to room temperature affords an iron—dithionite complex, (η5-C5H5)(CO)2FeS(O)2S(O)2Fe(CO)2(η5-C5H5).