- Supramolecular assembly of borate with quaternary ammonium: Crystal structure and tunable luminescent properties
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A new borate [C6H16N][B5O 6(OH)4] (1) is synthesized hydrothermally by the reaction of isopropyltrimethylammonium hydroxide with boric acid. It crystallizes in the triclinic space group P-1 with the parameters a=9.1578(10) A, b=9.372(9) A, c=9.9812(10) A, α=66.508(2)°, β=74.751(2)°, γ=81.893(2)°. The [B5O6(OH)4] - anions are interlinked via hydrogen bonding forming a 3D supramolecular network containing large cavities, where reside the (CH 3)3(i-C3H7) N+ cations. This borate shows tunable luminescent properties with temperature, heating-treatment, exciting-light, and solvents. The fluorescent intensity of 1 enhances 6-fold with decreasing the temperature from 25 K to 78 K. By treatment under different temperatures, the luminescence of 1 shifted from blue to white and the sample treated at 230 °C emits bright white light to naked eyes. The hybrid borate can disperse in different solvents, and shows a red-shifted and intense emission in polar solvents.
- Liang, Jie,Wang, Yong-Gang,Wang, Ying-Xia,Liao, Fu-Hui,Lin, Jian-Hua
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- Sequential addition reactions of two molecules of Grignard reagents to thioformamides
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(Chemical Equation Presented) Sequential addition reactions of two molecules of Grignard reagents to thioformamides were found to yield tertiary amines in an efficient manner. The addition of two different Grignard reagents can be accomplished by using one equivalent of arylmagnesium reagent in the first step. In the second step, a variety of reagents such as alkyl, alkenyl, aryl, and alkynyl reagents were used to afford the corresponding amines in good to high yields.
- Murai, Toshiaki,Ui, Kazuki,Narengerile
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scheme or table
p. 5703 - 5706
(2009/12/06)
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- METHOD FOR THE CONTINUOUS PRODUCTION OF AN AMINE
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The invention relates to a method for the continuous production of an amine by reacting a primary or secondary alcohol, aldehyde and/or ketone with hydrogen and a nitrogen compound, selected from the group including ammonia, primary and secondary amines, at a temperature in the range of from 80 to 350 °C in the presence of a zirconium dioxide-containing catalyst, the catalytically active weight of the catalyst prior to its reduction with hydrogen containing 90 to 99.8 % by weight of zirconium dioxide (ZrO2), 0.1 to 5.0 % by weight of oxygen-containing compounds of palladium and 0.1 to 5.0 % by weight of oxygen-containing compounds of platinum.
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Page/Page column 21
(2008/06/13)
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- Preparation of (meth) acrylic esters
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A process for preparing (meth)acrylic esters by esterifying (meth)acrylic acid with monohydric or polyhydric alcohols comprises adding to the reaction mixture still comprising (meth)acrylic acid corresponding to an acid number of at least 5 mg of KOH per 1 g of reaction mixture at least one amino compound having at least one primary, secondary or tertiary amino group.
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- Intramolecular motions in a series of crystalline benzylammonium bromides and dibenzylamines studied by CP/MAS NMR
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A series of 15 compounds including ammonium bromides containing one or two benzyl groups with H, methyl, isopropyl, tert-butyl and tert-amyl substituents and dibenzylamihe with N-isopropyl-, N-tert-butyl- and N-tert-amyl substituents have been synthesised and studied by CP/MAS NMR. The results of dynamic NMR studies on the solids suggest that there is a dramatically wide range of molecular motions occurring in this simple series of compounds: A combination of 2D CPEXSY, dynamic line shape analyses and T1ρ measurements reveals the considerable extent of intramolecular group motions including rotations of methyl, tert-butyl, tert-amyl and phenyl groups. Rates of rotation and activation parameters for these molecular motions are derived where appropriate. In the case of benzyl-tert-butylammonium bromide, where two independent molecules of the compound exist in the asymmetric unit it is shown that the independent processes of tert-butyl rotation in the two molecules have vastly different activation energies that differ by ca. 16 kJ mol-1. The extent of the motions observed suggests that commonly held prejudices about the rigidity of molecules in crystalline solids need revising.
- Riddell, Frank G.,Rogerson, Martin
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p. 493 - 504
(2007/10/03)
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- Borohydride reductions in dichloromethane: A convenient, environmentally compatible procedure for the methylation of amines
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The combination of zinc chloride and sodium borohydride in dichloromethane is used to effect reductive aminations of formaldehyde with a variety of primary and secondary amines containing potentially acid-sensitive functional groups in good to excellent yields.
- Bhattacharyya
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p. 2061 - 2069
(2007/10/02)
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- Base-promoted elimination reactions of acetaldehyde N-alkyl-N,N-dimethylhydrazonium salts. A convenient synthesis of N,N-dimethylalkylamines
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The title reaction was utilized for efficient conversion of S(N)2-reactive alkyl halides to the corresponding N,N-dimethylalkylamines.
- Smith,Marcucci,Tingue
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p. 381 - 389
(2007/10/02)
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- Thermolysis, Photolysis, and Acid Catalysis of an α-(Dimethylamino)azoalkane. Amino Stabilization of a Carbon Radical Center
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The unsymmetrical azoalkane 2-(tert-butylazo)-2-(dimethylamino)propane (7) has been synthesized cleanly by nucleophilic displacement of chloride from the corresponding α-chloroazoalkane 5 with dimethylamine.Thermolysis of 7 in hydrocarbon solvents affords typical radical-derived products and exhibits activation parameters ΔH(excit.) = 26.6 +/- 0.4 kcal/mol and ΔS(excit.) = -6.6 +/- 1.1 eu.Since the thermolysis rate of 7 is 104 faster than that of 1,2-di-tert-butyldiazene, the large stabilization of α-amino radicals is supported.Unusual products were obtained in acetonitrile, suggesting reduction of the azo linkage by 2-(dimethylamino)-2-propyl radicals and cleavage of the resulting hydrazyl radicals.In protic solvents, 7 undergoes acid catalyzed decomposition via tert-butyldiazene as a postulated intermediate.
- Engel, Paul S.,Wu, Wen-Xue
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p. 2720 - 2725
(2007/10/02)
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- Ion-Dipole Complexes in the Unimolecular Reactions of Isolated Organic Ions. Effect of N-Methylation on Olefin and Amine Loss from Protonated Aliphatic Amines
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The slow unimolecular fragmentation reactions os 18 gaseous protonated aliphatic amines of general formula R1NH(1+)R2R3 (R1=Prn, Pri, Bun, Bui, Bus, or But; R2,R3=H,CH3) are reported and discussed.Two decomposition routes are observed for a metastable ions R1NH(1+)R2R3.The first involves elimination of a neutral amine, R2R3NH, and formation of a carbocation, R1(1+), via a mechanism involving an incipient cation bound to the developing amine by an ion-dipole attraction.Rearrangement of the cation, to give thermodynamically more stable isomers, is feasible in these ion-dipole complexes.Further reorganization of the complexes leads to a species in which an incipient olefin 1-H> and an amine 2R3NH> are co-ordinated to a common proton.Dissociation of these proton-bound complexes, with retention of the proton by the developing amine, results in olefin loss, which is the secondreaction undergone by metastable ions R1NH(1+)R2R3.The relative abundance of amine expulsion is greater for protonated amines containing a primary alkyl group, R1, than is the case for isomeric ions containing secondary or tertiary alkyl groups.Progressive methylation of the nitrogen atom decreases the relative abundance of amine loss from R1NH(1+)R2R3, regardless of the nature of the principal alkyl group.These two trends are explained in terms of the energetics of the intermediates and products involved in the decomposition of the protonated amines.
- Bowen, Richard D.,Harrison, Alex G.,Reiner, Eric J.
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p. 1009 - 1014
(2007/10/02)
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