80612-33-5Relevant academic research and scientific papers
Tricarbonyl(phosphine)ferrates(2-), Fe(CO)3(PR3)2-, and their derivatives
Ellis, John E.,Chen, Yu-Sen
, p. 1350 - 1361 (2008/10/08)
A two-step synthesis of K2[Fe(CO)3(PR3)] (PR3 = PPh3, PMe2Ph, and PMe3) from the corresponding Fe(CO)4(PR3) has been developed. Treatment of Fe(CO)4(PR3) with a methanolic solution of [Et4N]OH provided the corresponding monohydrides HFe(CO)3(PR3)-. Deprotonation of monohydrides by K[sec-Bu3BH] in refluxing tetrahydrofuran gave 50-70% isolated yields (based on Fe(CO)4(PR3)) of the thermally stable but exceedingly air-sensitive salts K2[Fe(CO)3(PR3)], which were characterized by elemental analysis, infrared spectra, and reactivity patterns. These are the first isolated salts containing (phosphine)-carbonylmetalate dianions and are extremely reactive. They quickly deprotonated acetonitrile to give essentially quantitative yields of HFe(CO)3(PR3)- and reacted with triphenylstannyl chloride to provide Ph3SnFe(CO)3(PR3)-. Ligand exchange reactions of K2[Fe(CO)3(PPh3)] with CO and P(OMe)3 readily occurred at room temperature and gave 80-90% isolated yields of K2[Fe(CO)4] and K2[Fe(CO)3(P(OMe)3)]. The latter salt contains the first isolated (phosphite)carbonylmetalate dianion and was characterized by elemental analyses and infrared spectra as a triphenyltin derivative, (Ph3Sn)Fe(CO)3(P(OMe)3)-. Treatment of [Et4N][HFe(CO)3(PPh3)] with hot ethanol provided low yields (ca. 10%) of the bridging phosphide salt [Et4N][Fe2(CO)6(μ-CO)(μ-PPh 2)]. Full details on the molecular structure of this anion, which has been mentioned previously in the scientific literature (Kyba, E. P.; Davis; R. E.; Clubb, C. N.; Liu, S. T.; Palacios, H. A. O.; McKennis, J. S., Organometallics 1986, 5, 869), are reported for the first time. Crystal data: triclinic, space group P1 (No. 2); a = 11.140 (1) A?, b = 1-3.982 (4) A?, c = 10.161 (3) A?; α = 105.30 (2)°, β = 103.33 (2)°, γ = 77.21 (2)°, V = 1464 (1) A?3; Z = 2; R = 0.034; Rw = 0.039.
Solution and solid-state structures of salts of trans-HFe(CO)3PR3- including a study of alkali cation contact ion pairing
Ash, Carlton E.,Delord, Terry,Simmons, Debra,Darensbourg, Marcetta Y.
, p. 17 - 25 (2008/10/08)
Site-specific contact ion pairing interactions have been examined by v(CO) IR band analysis for Et4N+, K+, Na+ and Li+ salts of trans-HFe(CO)3P- (P = P(OMe)3, P(OEt)3, PMe3, PEt3, PPh2Me, and PPh3). Two major types of contact ion pairs were noted: one involving -Fe-CO?cation+ interaction and another involving -Fe?cation+ interaction. A combination of factors, solvent polarity, cation electrostatic potential, cation solvation, and size of the P ligand, determine the ion contact site selection. The indication of -Fe?cation+ interaction is supportive of a metal-based rather than hydride-based nucleophilicity in hydride/halide displacement reactions of HFe(CO)3P- with alkyl halides. The X-ray crystal structure of Et4N+HFe(CO)3PPh3- was determined. It crystallizes in the cubic system, space group Pa3, with cell parameters a = b = c = 17.670 (8) ?, V = 5533 (2) ?3, and Z = 8. The hydride ligand was not located but indicated to be trans to the PPh3 in a distorted trigonal-bipyramidal coordination geometry. The equatorial CO groups are bent away from the phosphine with a P-Fe-CO angle of 99.5°.
