55971-72-7Relevant 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.
Preparation of dianionic carbonyl complexes of molybdenum and tungsten
Maher, John M.,Beatty, Richard P.,Cooper, N. John
, p. 215 - 217 (2008/10/08)
Reduction of [M(CO)5(NMe3)] (M = Cr, Mo, W) in THF with alkali naphthalides gives high purity solutions of the corresponding [M(CO)5]2- dianions. Stable crystalline salts of the [M(CO)5]2- dianions (M = Mo, W) were prepared by complexing the sodium counterions with a cryptand. Reduction of [W(CO)4(NH3){P(i-Pr)3}] with sodium naphthalide gives [W(CO)4{P(i-Pr)3}]2-, as demonstrated by reaction with Ph3SnCl and counterion exchange to give [NEt4][W(CO)4{P(i-Pr)3}SnPh3].
