813-19-4Relevant academic research and scientific papers
Reactivity of lanthanide and yttrium hydrides and hydrocarbyls toward organosilicon hydrides and related compounds
Voskoboynikov, Alexander Z.,Parshina, Inna N.,Shestakova, Alia K.,Butin, Kim P.,Beletskaya, Irina P.,KuZ'Mina, Lyudmila G.,Howard, Judith A. K.
, p. 4041 - 4055 (1997)
The reaction of lanthanide and yttrium hydrocarbyls {Cp*2Ln(μ-Me)}2 (Cp* = tBuC5H4 (Cp′), Ln = Y (1), Tb (2), Yb (3), Lu (4); Cp* = Me3SiC5H4 (Cp″), Ln = Lu (5)), one of which, 2, has been characterized by X-ray crystal analysis, with various organosilicon, -germanium, and -tin hydrides (as well as some organoaluminum and -gallium hydrides) in hydrocarbon solution was found to yield the corresponding unsolvated dimeric lanthanide and yttrium hydrides {Cp*2Ln(μ-H)}2 rather than compounds with lanthanide-element (Si, Ge, Sn) bonding. Thus, the reaction involves hydride transfer to Ln rather than the silyl transfer studied earlier for pentamethylcyclopentadienyllanthanide hydrocarbyls. Dimeric compounds Cp*2Ln(μ-H)(μ-Me)LnCp*2 with different bridging ligands were isolated; they are intermediates in this reaction. Dimeric lanthanide and yttrium hydrides catalyze the H/D exchange in silanes. This catalytic reaction is most correctly described by a mechanism involving nucleophilic substitution at the silicon atom. Yttrium and lutetium hydrocarbyls 1 and 4 react with various alkoxysilanes to produce the dimeric alkoxides {Cp′2Ln(μ-OR)}2 or the hydrocarbyl alkoxides Cp′2Ln(μ-Me)(μ-OR)LnCp′2 (R = Me, Et), depending on the reaction conditions. The reaction of 4 with (MeO)4Si provided Cp′2Lu(μ-Me)(μ-OMe)LuCp′2, which has been characterized by X-ray crystal analysis. This compound contains one methyl bridge (Lu-C 2.57(2) and 2.58(2) A?) and nonsymmetrically bonded μ-OMe ligand (Lu-O 2.20(2) and 2.12(2) A?). The reaction of 1 and 4 with Me3SiCl leads to the corresponding dimeric chlorides {Cp′2Ln(μ-Cl)}2 only. Thus, the reaction of lanthanide and yttrium hydrocarbyls with various heterosubstituted organosilanes R3SiX, where X = H, OR, or Cl, is a selective and convenient synthetic method in the chemistry of the group 3 elements. Complexes with Ln(μ-H)(μ-Me)Ln and Ln(μ-H)(μ-Cl)Ln bridging were prepared in high yield by the exchange reactions between the corresponding dimeric compounds {Cp*2Ln(μ-X)}2 (X = H, Me, Cl) in a hydrocarbon solution. The capacities of various bridging fragments to undergo reversible cleavage (dissociation) in the hydrocarbon solution increase in the sequence Ln-O(Me)-Ln ? Ln-Cl-Ln Ln-H-Ln Ln-Me-Ln.
Redox-Active-Ligand-Mediated Formation of an Acyclic Trinuclear Ruthenium Complex with Bridging Nitrido Ligands
Bagh, Bidraha,Broere, Dani?l L. J.,Siegler, Maxime A.,van der Vlugt, Jarl Ivar
, p. 8381 - 8385 (2016)
Coordination of a redox-active pyridine aminophenol ligand to RuIIfollowed by aerobic oxidation generates two diamagnetic RuIIIspecies [1 a (cis) and 1 b (trans)] with ligand-centered radicals. The reaction of 1 a/1 b with excess NaN3under inert atmosphere resulted in the formation of a rare bis(nitrido)-bridged trinuclear ruthenium complex with two nonlinear asymmetrical Ru-N-Ru fragments. The spontaneous reduction of the ligand centered radical in the parent 1 a/1 b supports the oxidation of a nitride (N3?) to half an equivalent of N2. The trinuclear omplex is reactive toward TEMPO-H, tin hydrides, thiols, and dihydrogen.
Transformations of organosilanes by Pt(II) complexes with hemilabile P,N-chelating ligands
Schubert, Ulrich,Pfeiffer, Jürgen,St?hr, Frank,Sturmayr, Dietmar,Thompson, Susan
, p. 53 - 58 (2002)
The article reviews the author's own work to enhance the reactivity of Pt(II) complexes towards organosilanes by employing hemilabile chelating ligands R2N-R′-PPh2 (P∩N). Variation of the groups R and R′ allows to influence the react
Thermodynamic, Kinetic, Structural, and Computational Studies of the Ph3Sn-H, Ph3Sn-SnPh3, and Ph3Sn-Cr(CO)3C5Me5 Bond Dissociation Enthalpies
Cai, Xiaochen,Majumdar, Subhojit,Fortman, George C.,Koppaka, Anjaneyulu,Serafim, Leonardo,Captain, Burjor,Temprado, Manuel,Hoff, Carl D.
, p. 10751 - 10766 (2016)
The kinetics of the reaction of Ph3SnH with excess ?Cr(CO)3C5Me5 = ?Cr, producing HCr and Ph3Sn-Cr, was studied in toluene solution under 2-3 atm CO pressure in the temperature range of 17-43.5 °C. It was found to obey the rate equation d[Ph3Sn-Cr]/dt = k[Ph3SnH][?Cr] and exhibit a normal kinetic isotope effect (kH/kD = 1.12 ± 0.04). Variable-temperature studies yielded ΔH? = 15.7 ± 1.5 kcal/mol and ΔS? = -11 ± 5 cal/(mol·K) for the reaction. These data are interpreted in terms of a two-step mechanism involving a thermodynamically uphill hydrogen atom transfer (HAT) producing Ph3Sn? and HCr, followed by rapid trapping of Ph3Sn? by excess ?Cr to produce Ph3Sn-Cr. Assuming an overbarrier of 2 ± 1 kcal/mol in the HAT step leads to a derived value of 76.0 ± 3.0 kcal/mol for the Ph3Sn-H bond dissociation enthalpy (BDE) in toluene solution. The reaction enthalpy of Ph3SnH with excess ?Cr was measured by reaction calorimetry in toluene solution, and a value of the Sn-Cr BDE in Ph3Sn-Cr of 50.4 ± 3.5 kcal/mol was derived. Qualitative studies of the reactions of other R3SnH compounds with ?Cr are described for R = nBu, tBu, and Cy. The dehydrogenation reaction of 2Ph3SnH → H2 + Ph3SnSnPh3 was found to be rapid and quantitative in the presence of catalytic amounts of the complex Pd(IPr)(P(p-tolyl)3). The thermochemistry of this process was also studied in toluene solution using varying amounts of the Pd(0) catalyst. The value of ΔH = -15.8 ± 2.2 kcal/mol yields a value of the Sn-Sn BDE in Ph3SnSnPh3 of 63.8 ± 3.7 kcal/mol. Computational studies of the Sn-H, Sn-Sn, and Sn-Cr BDEs are in good agreement with experimental data and provide additional insight into factors controlling reactivity in these systems. The structures of Ph3Sn-Cr and Cy3Sn-Cr were determined by X-ray crystallography and are reported. Mechanistic aspects of oxidative addition reactions in this system are discussed.
Spectroscopic studies of tributylstannyl radical. Rates of formation, termination, and abstraction determined by transient absorption spectroscopy
Shaw, Wendy J.,Kandandarachchi, Pramod,Franz, James A.,Autrey, Tom
, p. 2080 - 2086 (2004)
Transient absorption spectroscopy (TAS) was used to measure the rate of formation and the rate of self-termination of the main group metal hydride, tri-n-butyltin hydride (Bu3-SnH). Irradiation of di-tert-butyl peroxide in the presence of Busu
Convenient one-pot synthesis of hexa-n-butylditin from bis(tri-n-butyltin) oxide
McAlonan, Helena,Stevenson, Paul J.
, p. 4021 - 4022 (1995)
Hexa-n-butylditin is prepared in high yield (83%), by reduction of bis(tri-n-butyltin) oxide with sodium borohydride in ethanol. The first stage is reduction to tri-n-butyltin hydride (not isolated), which rapidly gives hexa-n-butylditin with the loss of hydrogen under the basic reaction conditions.
Illuminating Stannylation
Sakamoto, Kyoka,Nagashima, Yuki,Wang, Chao,Miyamoto, Kazunori,Tanaka, Ken,Uchiyama, Masanobu
supporting information, p. 5629 - 5635 (2021/05/04)
We have developed photoboosted stannylation reactions of terminal alkynes (linear-selective hydrostannylation) and fluoroarenes (defluorostannylation), in which the stannyl anion is photoexcited to an excited triplet (T1) stannyl diradical species. This u
Bis(pentafluorophenyl)phenothiazylborane-an intramolecular frustrated Lewis pair catalyst for stannane dehydrocoupling
Bentley, Jordan N.,Caputo, Christopher B.,Pradhan, Ekadashi,Zeng, Tao
, p. 16054 - 16058 (2020/12/03)
We synthesized a novel Lewis acidic aminoborane containing a phenothiazyl substituent and demonstrated its potential to catalytically promote the dehydrocoupling of tin hydrides. The observed reactivity would imply a homolytic frustrated Lewis pair type mechanism, however computational analysis suggests a heterolytic mechanism for this reaction. This result represents one of the first frustrated Lewis pair systems to dehydrocouple stannanes in a heterolytic fashion.
A Drastic Effect of TEMPO in Zinc-Catalyzed Stannylation of Terminal Alkynes with Hydrostannanes via Dehydrogenation and Oxidative Dehydrogenation
Kai, Yuichi,Oku, Shinya,Sakurai, Kyoko,Tani, Tomohiro,Tsuchimoto, Teruhisa
supporting information, (2019/08/21)
With a system consisting of a catalytic zinc Lewis acid, pyridine, and TEMPO in a nitrile medium, terminal alkynes coupled with HSnBu3, providing alkynylstannanes with structural diversity. The resulting alkynylstannane, without being isolated, could be directly used for Pd- and Cu-catalyzed transformations to deliver internal alkynes and more intricate tin-atom-containing molecules. Mechanistic studies indicated that TEMPOSnBu3 formed in situ from TEMPO and HSnBu3 works to stannylate the terminal alkyne in collaboration with the zinc catalyst, and that both of dehydrogenation and oxidative dehydrogenation processes are uniquely involved in a single reaction. (Figure presented.).
Nickel-catalyzed decarbonylative stannylation of acyl fluorides under ligand-free conditions
Wang, Xiu,Wang, Zhenhua,Liu, Li,Asanuma, Yuya,Nishihara, Yasushi
, (2019/05/24)
Nickel-catalyzed decarbonylative stannylation of acyl fluorides under ligand-free conditions was disclosed. A variety of aromatic acyl fluorides are capable of reacting with silylstannanes in the presence of cesium fluoride. A one-pot decarbonylative stannylation/Migita-Kosugi-Stille reaction of benzoyl fluoride, giving rise to the direct formation of the corresponding cross-coupled products, further demonstrated the synthetic utility of the present method. This newly developed methodology with a good functional-group compatibility via C-F bond cleavage and C-Sn bond formation under nickel catalysis opens a new area for the functionalization of acyl fluorides in terms of carbon-heteroatom bond formation.
