55997-66-5Relevant academic research and scientific papers
Synthesis and properties of the pentacarbonylmetalates of the group 6 metals
Maher, John M.,Beatty, Richard P.,Cooper, N. John
, p. 1354 - 1361 (2008/10/08)
Reduction of the amine complexes [M(CO)5(NMe3)] (M = Cr, Mo, W) with sodium naphthalenide in THF provides a convenient route to the pentacarbonylmetalates of the group 6 metals in an innocuous solvent. The synthetic utility of the method has been demonstrated by reaction of the dianions with Ph3SnCl to give [NEt4][M(CO)5SnPh3] (M = Cr, Mo, W) in 76, 92, and 62% yield, respectively, after counterion exchange. The sodium salts of [Mo(CO)5]2- and [W(CO)5]2- cannot be handled in the solid state but can be readily separated from the NMe3 and C10H8 byproducts of the reduction. Naphthalenide reduction has also been used to prepare [W(CO)5]2- with Li+ and K+ counterions, and crystalline salts of [W(CO)5]2- and [Mo(CO)5]2- have been prepared by adding pentamethyldiethylenetriamine to Li2[W(CO)5] and a cryptand (K-2.2.1) to Na2[M(CO)5] (M = Mo, W). Crystals of the encrypted sodium salts are indefinitely stable, and a brief account is given of an X-ray diffraction study which establishes a slightly distorted trigonal-bipyramidal structure for the tungsten anion in the solid state. The IR spectra of the [Na(K-2.2.1)]+ salts in CH3CN exhibit the two band patterns expected in the carbonyl stretching region if the anions have D3h structures without counterion contact ion pairing, but ion pairing has a marked effect on solution spectra of simple alkali-metel salts of [W(CO)5]2+. The Li+ salt exhibits isocarbonyl absorptions indicating interaction with two of the equatorial carbonyls, while Na2[W(CO)5] and K2[W(CO)5] have high-energy carbonyl stretches indicative of contact ion pairing with direct M-W interaction.
Highly reduced organometallics. 14. Six- and seven-coordinate organotin derivatives of the tetrasodium tetracarbonylmetalates(4-) of chromium, molybdenum, and tungsten
Lin, Jiann T.,Hagen, Gary P.,Ellis, John E.
, p. 1145 - 1150 (2008/10/08)
Treatment of Na4[M(CO)4] with 2 equiv of Ph3SnCl provides approximately 50% yields of [Et4N]2[(Ph3Sn)2M(CO)4] for M = Cr and W and very low yields for M = Mo. The reaction of L2M(CO)4, where L2 = norbornadiene, cyclooctadiene, tetramethylethylenediamine, or ethylenediamine (M = Cr, Mo, W), with 2 equiv of Ph3SnLi is a more facile and often higher yield route (60-70% for M = Cr, Mo; 35% for M = W) to the same dianions. These materials react with Ph3SnCl to provide 30-40% yields of [Et4N][(Ph3Sn)3M(CO)4], in which Cr, Mo, and W are seven-coordinate. Reactions of [Et4N]2-[(Ph3Sn)2M(CO)4] (M = Cr, Mo) with acetic acid, [Me2NCCl2]Cl, and methyl iodide in acetonitrile provide 30-40% yields of [Et4N][H(Ph3Sn)2M(CO)4], containing seven-coordinate metals, trans-Ph3Sn(CO)4M≡ CNMe2, and [Et4N][(Ph3Sn)M(CO)4(CH3CN)], respectively. The coordinated acetonitrile in the latter compounds is slowly displaced by PPh3 in acetonitrile at 25°C to give 35-50% yields of [Et4N]-[Ph3SnM(CO)4(PPh3)]. All of these new materials are characterized by elemental analyses and IR and 1H NMR spectra.
