97186-70-4Relevant academic research and scientific papers
Late to the Party: Synthesis and Characterization of Tellurium and Selenium Half-Sandwich Complexes
Bart, Suzanne C.,Jones, Leighton O.,Kieser, Jerod M.,Schatz, George C.,Uible, Madeleine C.,Zeller, Matthias
supporting information, p. 4104 - 4109 (2021/12/17)
We report the synthesis and characterization of the first series of tellurium and selenium complexes featuring an ν5-cyclopentadienyl ligand. Reaction of Ph3TeX (X = Cl, S2CNEt2) with MCpR (M = Li, K; R = H, Me4, Me5) results in high yields of [Cp][TePh3] (1), [CpMe4][TePh3] (2), and [Cp*][TePh3] (3), respectively. Similarly, reaction of Ph3SeCl with LiCp and KCp? furnishes [Cp][SePh3] (4) and [Cp*][SePh3] (5). Each was characterized by X-ray crystallography, revealing similar ν5-coordination with little distortion from an idealized half-sandwich geometry, presumably from the remaining lone pair on tellurium and selenium. The Te-centroid distances are relatively long (1: 2.770(3), 2: 2.746(1), and 3: 2.733(1) ?), suggesting a mostly ionic interaction. Se-centroid distances (4: 2.748(3), 5: 2.707(2), 2.730(2) ?) were found to be surprisingly similar despite its smaller atomic radius. Compounds 2, 3, and 5 display rapid decomposition at room temperature, extruding a phenylated cyclopentadiene and the respective diphenylchalcogenide. The nature of bonding within these complexes was investigated through DFT methods and found to be primarily ionic in nature.
Oxygen atom insertion into iron(II) phenyl and methyl bonds: A key step for catalytic hydrocarbon functionalization
Mei, Jiajun,Pardue, Daniel B.,Kalman, Steven E.,Gunnoe, T. Brent,Cundari, Thomas R.,Sabat, Michal
, p. 5597 - 5605 (2015/02/19)
Oxy-functionalization of metal-alkyl and ?aryl bonds is a key step in potential hydrocarbon oxidation catalysis. However, well-defined examples of M-R to ROH conversion are rare, especially for first-row transition metals. CpFe(CO)(NCMe)Ph reacts with oxygen or hydrogen peroxide to produce benzoic acid. Removing CO from the CpFe(L)(L')Ph framework allows simple oxygen atom insertion into the Fe-Ph bond. CpFe(P(OCH2)3CEt)2Ph reacts with Me3NO in THF to produce PhOH in high yield when Bronsted acids are added. Studies show that light promotes P(OCH2)3CEt dissociation from CpFe(P(OCH2)3CEt)2Ph, which facilitates the conversion to PhOH. The methyl analogue CpFe[P(OCH2)3CEt]2Me reacts with oxidants to produce MeOH.
Organolanthanide and organoactinide oxidative additions exhibiting enhanced reactivity. 5. Stoichiometry, kinetic, and mechanistic studies of (C5Me5)2YbII·OEt2 oxidative-addition reactions and of (C5Me5)2YbIIIR (R = R, X) YbIII ...
Finke,Keenan,Watson
, p. 263 - 277 (2008/10/08)
Full title: Organolanthanide and organoactinide oxidative additions exhibiting enhanced reactivity. 5. Stoichiometry, kinetic, and mechanistic studies of (C5Me5)2YbII·OEt2 oxidative-addition reactions and of (C5Me5)2YbIIIR (R = R, X) YbIII-Grignard reactions with alkyl and aryl halides. Evidence for the dominance of inner-sphere mechanisms. (C5Me5)2YbII·OEt 2 undergoes atom-abstraction oxidative addition with alkyl and aryl halides according to the generalized stoichiometry 1.0(C5Me5)2YbII·OEt 2 + (1 + a)RX → (1 - a)(C5Me5)2YbIIIX + (a)(C5Me5)1YbIIIX2 + (a)C5Me5R + 1.0Et2O + 1.0[R-R, R-H(alkanes), R(-H)(olefins)]. A reactive Yb-alkyl intermediate, (C5Me5)2YbIIIR, is formed from R? trapping by diamagnetic (C5Me5)2YbII. This (C5Me5)2YbIIIR intermediate and the initial product (C5Me5)2YbIIIX react further with RX in subsequent YbIII-Grignard reactions that are retarded by added Et2O and, therefore, apparently operate via an inner-sphere pathway. The observed YbIII-Grignard stoichiometries are (C5Me5)2YbIIIR + 2RX → (C5Me5)2YbIIIX2 + C5Me5R + R-R and (C5Me5)2YbIIIX + RX → (C5Me5)1YbIIIX2 + C5Me5R. The absolute rates of reaction of RX with (C5Me5)2YbII·OEt2 are found to be first-order each in (C5Me5)2YbII·OEt-2 and RX, with an added inverse dependence upon Et2O. The Et2O dependence is consistent with a requirement for a site of coordinative unsaturation and an inner-sphere pathway. Comparison of the rates of reactions of (C5Me5)2UIII(Cl)(THF) and (C5Me5)2YbII·OEt2 with RX provides compelling evidence for participation of electron transfer in these net atom-abstraction reactions.
SOME RELATIONSHIPS OF THE 1,2-SHIFT OF THE MIGRANTS IN THE REARRANGEMENTS OF CARBOCATIONS AND NEUTRAL COMPOUNDS. THE DEGENERATE REARRANGEMENT OF 5-PHENYL-1,2,3,4,5-PENTAMETHYL-1,3-CYCLOPENTADIENE
Borodkin, G. I.,Susharin, E. R.,Shakirov, M. M.,Shubin, V. G.
, p. 1446 - 1456 (2007/10/02)
The kinetics of the degenerate rearrangement of 5-phenyl-1,2,3,4,5-pentamethyl-1,3-cyclopentadiene, which is realized by a 1,2-shift of the phenyl group, were studied by the labeled atom method.The data from quantum-chemical calculations agree with this mechanism.Linear correlations were obtained between the log k, ΔG%, and Ea values for the 1,2-shift of the phenyl group in the diene and in the "long-lived" carbocations and the corresponding values for the methyl group as standard migrant (Rm).The ΔG%Rm = a + bΔG%CH3 relationships for the migrants Rm = H, CH3, C6H5, and NO2 are such that the "additivity-selectivity" principle is observed above the isoselectivity point, which lies in the region of small ΔG%CH3 values (ca. 4 kcal/mole).
