- A Simple Route to Calcium and Strontium Hydride Clusters
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The first strontium hydride complex has been obtained by simply treating Sr[N(SiMe3)2]2 with PhSiH3 in the presence of PMDTA. The Sr complex Sr6H9[N(SiMe3)2]3?(PMDTA)3 crystallizes as an “inverse cryptand”: an interstitial H? is surrounded by a Sr6H84+ cage decorated with amide and PMDTA ligands. The analogous Ca complex could also be obtained and both retain their solid-state structures in solution: 1H NMR spectra in C6D6 show two doublets and one nonet (4:4:1). Up to 90 °C, no coalescence is observed. The Ca cluster was investigated by DFT calculations and shows atypically low charges on Ca (+1.14) and H (?0.59) which signifies an unexpectedly low ionicity. AIM analysis shows hydride???hydride bond paths with considerable electron densities in the bond critical point. The clusters thermally decompose into larger, undefined, metal hydride aggregates.
- Maitland, Brant,Wiesinger, Michael,Langer, Jens,Ballmann, Gerd,Pahl, Jürgen,Elsen, Holger,F?rber, Christian,Harder, Sjoerd
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- A METHOD FOR THE ALKYLATION OF AMINES
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The present invention pertains to a method for the alkylation of amines. In particular, the present invention relates to a method for preparing N, N, N', N , N -pentamethyldiethylenetriamine by reacting diethylenetriamine with methanol in the presence of hydrogen and a metal catalyst.
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Page/Page column 18-21
(2021/09/11)
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- A METHOD FOR PREPARING ALKYLATED AMINES
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The present invention pertains to a method for preparing an alkylated amine by reacting a primary or secondary amine with an alcohol in the presence of hydrogen, a metal catalyst supported by photosensitive titanium oxide, and UV irradiation. Advantageously, the reaction can be carried out under mild reaction conditions.
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Page/Page column 31; 32
(2021/09/11)
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- Amine catalyst for producing polyurethane and polyisocyanurate
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An amine catalyst-for production of a polyurethane and a polyisocyanurate is provided which comprises a quaternary ammonium compound represented by General Formula (1): where R1 to R6 are independently a linear or branched saturated hydrocarbon group of 1 to 4 carbon atoms; R7 and R8 are independently a linear or branched, saturated or unsaturated hydrocarbon group of 2 to 12 carbon atoms; n is a number of 0 to 3 provided that at n=o any one of R1, R2 and R3, and R5 and/or R6 may be linked together to form a heterocycle, or at n=1, 2, or 3, R5 or R6 and R4 may be linked together to form a heterocycle; A is a carbonate group or an organic acid group; and X is number of 1 to 2. The catalyst has high activity in formation of polyurethane foams and polyisocyanurate foams, having less odor, and producing foams of high fire retardance, having high curability, high retarding effect, and low corrosiveness.
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- Coordination to RMg+ and RZn+ cations
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Addition of a second coordinating agent (coord*) to a solution of RM(coord)+A- (R = ethyl or neopentyl, M = Zn or Mg, A- = 1,2,3,4-tetraphenylcyclopentadienyl) can provide equilibrium mixtures of these compounds, coord, and RM(coord*)+A-. This exchange with RMg(coord)+ requires the addition of a small amount of R2Mg, but added R2Zn is not necessary for exchanges with RZn(coord)+. The equilibrium constants provide information about the relative abilities of different coordinating agents to coordinate to RM+ and reveal significant differences between coordination to RMg+ and RZn+. Reactions of RM(coord)+ with R′2M (R = ethyl or neopentyl for RMg(coord)+ and ethyl, isopropyl, tert-butyl, neopentyl, or p-methylphenyl for RZn(coord)+) provide equilibrium mixtures of these components, R′M(coord)+, and R2M. The equilibrium constants provide information about the effect of R on stability. An X-ray structure of p-methylphenylzinc(2,5,8,11-tetramethyl-2,5,8,11-tetraazadodecane)+ shows that just three of the N atoms are coordinated to Zn. The effects of coord, R, and metal on RM(coord)+ stability are discussed, and the abilities of coordinating agents to coordinate to RM+, to slow allylic isomerization of (CH2 double bond CMeCH2)2Zn, and to convert R2Zn to RZn(coord)+ are compared.
- Tang, Hui
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p. 4810 - 4819
(2008/10/08)
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- W(CO)3(PMTA) (PMTA = MeN(CH2CH2NMe2)2) as a starting material for syntheses of W(CO)3(PR3)3, W(CO)3(η6-arene), and the protonated W(H)(CO)3(PR3)3+ complexes
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A new and improved method for the synthesis of M(CO)3(PMTA) (M = W, Mo) from M(CO)6 and PMTA (MeN(CH2CH2NMe2)2) is described.The tridentate nitrogen ligand in W(CO)3(PMTA) is replaced, under relatively mild conditions, by tertiary phosphines (PMe3, PEt3, PMe2Ph, PMePh2, PhP(CH2CH2PPh2)2, CH3C(CH2PPh2)3, and Ph2P(CH2)nPPh2 where n = 1, 2) and arenes (C6H6, MeC6H5, p-Me2C6H4, C6Me6, C6H5Cl), which provides a general synthetic method for the preparation of W(CO)3(PR3)3 and W(CO)3(η6-arene) complexes.The reactions of W(CO)3(L)3 with CF3SO3H in CH2Cl2 solution yield the hydrido derivatives W(H)(CO)3(L)3+ which were characterized by their 1H and 31P NMR spectra at different temperatures.These studies show the W(H)(CO)3(L)3+ complexes to be fluxional as a result of both hydride and phosphine ligand migration.
- Zanotti, Valerio,Rutar, V.,Angelici, Robert J.
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p. 177 - 191
(2007/10/02)
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- Transalkylation Reaction. Homogeneous Catalytic Formation of C-N Bonds
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We have performed kinetic and mechanistic studies on homogeneous ruthenium-catalyzed transalkylation of tertiary amines.From these studies we have derived a kinetic expression for transalkylation catalysis based on initial reaction rates.We find that transalkylation proceeds most efficiently in alcoholic solvents (e.g., MeOH or EtOH), under a slight pressure of CO, with a mixed-metal, iron-ruthenium catalyst.The mechanism appears to be in one which a metal cluster of at least two and most probably three atoms binds the amine through insertion into an α C-H bond to give a metallazacyclopropane or metal-iminium complex.Nucleophilic attack by free amine on the complex, or an immediate derivative, follows, and subsequent rearrangement of the intermediate formed gives transalkylation products.The catalyst system has been tested as a synthetic tool for the oligomerization and cyclization of tertiary diamines.These preliminary studies have been quite succesful.Thus, N,N,N',N'-tetramethylethylenediamine can be transformed into Me3N and N,N'-dimethylpiperazine with good conversion and high selectivity.N,N,N',N'-Tetraethylethylenediamine can be transformed into Et3N and the linear, perethyl, ethylenediamine dimer, trimer, tetramer, and pentamer with excellent conversion.
- Wilson, Robert B.,Laine, Richard M.
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p. 361 - 369
(2007/10/02)
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- AFFINITIES OF CROWN ETHERS, GLYMES, AND POLYAMINES FOR ALKALI PICRATES IN TOLUENE. APPLICATION OF POLYMER-SUPPORTED LINEAR POLYETHERS.
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This work reports the measurements of K values for polyamines, glymes, a few glycols (including that of a long-chain polyethylene glycol, carbowax 6000), and some frequently used cation-binding ligands as complexers of lithium or sodium picrate in toluene as solvent. K values for different resins obtained with the same soluble ligand provide a comparison of the effectiveness of these resins in binding ionic solutes.
- Xu,Smid
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p. 3790 - 3796
(2007/10/02)
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