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Analogous Reactions (analogous + reaction)
Kinds of Analogous Reactions Selected AbstractsMultifunctional Polymethacrylates Obtained Via ATRP of Functional and Reactive Monomers Followed by Polymer Analogous Reaction with Functional AminesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 19 2008Dragos Popescu Abstract Starting from methyl methacrylate (MMA), butyl methacrylate (BMA), allyl methacrylate (AMA), phenoxycarbonyloxy ethyl methacrylate (PCEMA), and functional amines different multifunctional polymethacrylates are accessible. The reactive monomer PCEMA was synthesized starting from 2-hydroxyethyl methacrylate, and then copolymerized via ATRP with other methacrylates in order to obtain reactive copolymers which were subjected to polymer analogous reactions with different functional amines leading to multifunctional polymethacrylates. These can be used for the preparation of multifunctional surfaces. [source] Synthesis and Structure of Trialkyltantalum Complexes Stabilized by Aminopyridinato LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2006Awal Noor Abstract (4-Methylpyridin-2-yl)(trimethylsilyl)amine (1), (6-methylpyridin-2-yl)(trimethylsilyl)amine (2), and (2,6-diisopropylphenyl)(pyridin-2-yl)amine (3) were deprotonated and used as ligands to synthesize trialkyltantalum complexes. The reaction of 2 equiv. of 1 or 2 with pentabenzyltantalum afforded tribenzyltantalum(V) complexes by toluene elimination. Analogous reaction using 3 failed. Lithiation of 3 followed by the reaction with tribenzyltantalum dichloride gave rise to the corresponding tribenzyl complex. Other alkyltantalum complexes stabilized by this ligand environment can be prepared by treating tantalum pentachloride with 2 equiv. oflithiated 3 to form a bis(aminopyridinato)tantalum trichloride. The reaction of this trichloride with 3 equiv. of alkyllithium compounds like methyllithium affords the corresponding trialkyltantalum complexes. X-ray diffraction studies of four of the synthesized complexes were carried out. They adopt two different coordination environments, either slightly distorted capped octahedrons (sterically less demanding aminopyridinato ligands) or pentagonal bipyramids (bulkier aminopyridinato ligands). The alkyl species were surprisingly stable at elevated temperatures and no formation of mixed alkyl/alkylidene complexes was observed. Alkyl cation formation and the behaviour of a selection of these compounds in olefin polymerization were explored. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Synthesis and Reactivity of Oxametallacyclic Niobium Compounds by Using ,,,-Unsaturated Carbonyl Ligands,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2008Rocío A. Arteaga-Müller Abstract Reduction of mono(cyclopentadienyl)niobium complexes [NbCpRCl4] [CpR = C5Me4H (1), C5H4SiMe2Cl (2), C5H4SiMe3 (3)] with Na/Hg in the presence of methyl methacrylate [MMA, CH2=C(Me)C(O)OMe (a)], methyl acrylate [MA, CH2=CHC(O)OMe (b)] and mesityl oxide [MO, CMe2=CHC(O)Me (c)] afforded the corresponding derivatives [NbCpRCl2(LL)] [CpR = C5Me4H, LL = MMA (1a); CpR = C5H4SiMe2Cl, LL = MMA (2a), MA (2b), MO (2c); CpR = C5H4SiMe3, LL = MMA (3a), MA (3b)] in variable yields depending on both the cyclopentadienyl and the ,,,-unsaturated carbonyl compounds. The reactivity of these complexes was studied toward protic and Lewis acids. Addition of triflic acid TfOH (Tf = CF3SO2) to 3b gave the triflate complex [NbCpRCl2{(CH2)2C(O)OMe}(OTf)] [CpR = C5H4SiMe3 (4)]. The Lewis acids E(C6F5)3 (E = B, Al) reacted with complexes 2b and 3b to give the three-membered metallacyclic (or ,2 -enone) compounds [NbCpRCl2{,2 -CH2=CHC(OMe){O·E(C6F5)3}}] [CpR = C5H4SiMe2Cl, E = B (5), Al (6); CpR = C5H4SiMe3, E = B (7), Al (8)], which decomposed to the corresponding adducts MA·E(C6F5)3. The same reaction with the 2a and 3a derivatives only allowed the observation of the corresponding adducts MMA·E(C6F5)3. Complexes 2a,b and 3a,b reacted with CO with elimination of the acrylate compounds, MA and MMA, respectively, to give the carbonylniobium(III) compounds [NbCpRCl2(CO)2]2 [CpR = C5H4SiMe2Cl (9), C5H4SiMe3 (10)]. Analogous reactions with CNAr showed the elimination of the free MA and MMA compounds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Steric Modulation of Coordination Number and Reactivity in the Synthesis of Lanthanoid(III) FormamidinatesCHEMISTRY - A EUROPEAN JOURNAL, Issue 29 2007Marcus Abstract Reactions of a range of the readily prepared and sterically tunable N,N,-bis(aryl)formamidines with lanthanoid metals and bis(pentafluorophenyl)mercury (Hg(C6F5)2) in THF have given an extensive series of tris(formamidinato)lanthanoid(III) complexes, [Ln(Form)3(thf)n], namely [La(o -TolForm)3(thf)2], [Er(o -TolForm)3(thf)], [La(XylForm)3(thf)], [Sm(XylForm)3], [Ln(MesForm)3] (Ln=La, Nd, Sm and Yb), [Ln(EtForm)3] (Ln=La, Nd, Sm, Ho and Yb), and [Ln(o -PhPhForm)3] (Ln=La, Nd, Sm and Er). [For an explanation of the N,N, - bis(aryl)formamidinate abbreviations used see Scheme,1.] Analogous attempts to prepare [Yb(o -TolForm)3] by this method invariably yielded [{Yb(o -TolForm)2(,-OH)(thf)}2], but [Yb(o -TolForm)3] was isolated from a metathesis synthesis. X-ray crystal structures show exclusively N,N, - chelation of the Form ligands and a gradation in coordination number with Ln3+ size and with Form ligand bulk. The largest ligands, MesForm, EtForm and o -PhPhForm give solely homoleptic complexes, the first two being six-coordinate, the last having an ,1 -,-ArLn interaction. Reaction of lanthanoid elements and Hg(C6F5)2 with the still bulkier DippFormH in THF resulted in CF activation and formation of [Ln(DippForm)2F(thf)] (Ln=La, Ce, Nd, Sm and Tm) complexes, and o -HC6F4O(CH2)4DippForm in which the formamidine is functionalised by a ring-opened THF that has trapped tetrafluorobenzyne. Analogous reactions between Ln metals, Hg(o -HC6F4)2 and DippFormH yielded [Ln(DippForm)2F(thf)] (Ln=La, Sm and Nd) and 3,4,5-F3C6H2O(CH2)4DippForm. X-ray crystal structures of the heteroleptic fluorides show six-coordinate monomers with two chelating DippForm ligands and cisoid fluoride and THF ligands in a trigonal prismatic array. The organometallic species [Ln(DippForm)2(CCPh)(thf)] (Ln=Nd or Sm) are obtained from reaction of Nd metal, bis(phenylethynyl)mercury (Hg(CCPh)2) and DippFormH, and the oxidation of [Sm(DippForm)2(thf)2] with Hg(CCPh)2, respectively. The monomeric, six-coordinate, cisoid [Ln(DippForm)2(CCPh)(thf)] complexes have trigonal prismatic geometries and rare (for Ln) terminal CCPh groups with contrasting LnCC angles (Ln=Nd, 170.9(4)°; Ln=Sm, 142.9(7)°). Their formation lends support to the view that [Ln(DippForm)2F(thf)] complexes arise from oxidative formation and CF activation of [Ln(DippForm)2(C6F5)] intermediates. [source] Synthesis, Characterization, and Reactivity of Lanthanide Complexes with Bulky Silylallyl LigandsISRAEL JOURNAL OF CHEMISTRY, Issue 4 2002Timothy J. Woodman The synthesis of new lanthanide allyl complexes of enhanced stability and solubility in saturated hydrocarbons based on silyl-substituted allyl ligands is reported. Thus the potassium salt K(CH2CHCHSiMe3) (1) reacts with YCl3 in tetrahydrofuran to give the tris -allyl complex Y(CH2CHCHSiMe3)3 (2), while K(CH2CHCHSiMe2tBu) (3) affords Y(CH2CHCHSiMe2tBu)3(THF)1.5 (4). Slow re-crystallization of 4 from light petroleum in the presence of tert -butylcyanide led to multiple insertion to give the sec -amido complex Y{NHC(tBu)(CH)3SiMe2tBu}2{,2 -NHC(tBu)CH=CHCH2SiMe2tBu)CH(CHCHSiMe2tBu)CtBuNH}(THF)·(CH3CH(Me)(CH2)2CH3) (5), which was crystallographically characterized. The reaction of ScCl3(THF)3 with two equivalents of Li{1,3-C3H3(SiMe3)2} in tetrahydrofuran gives the bis -allyl complex {1,3-C3H3(SiMe3)2}2Sc(,-Cl)2Li(THF)2 (6), while the analogous reaction of K{1,3-C3H3(SiMe3)2} (7) with either LaCl3 or YCl3 in tetrahydrofuran affords the bis -allyl complexes MCl{1,3-C3H3(SiMe3)2}2(THF)x (8, M = La, x = 1; 9, M = Y, x = 0). An attempt to prepare the similar neodymium complex gave the mono -allyl complex NdI2{1,3-C3H3(SiMe3)2}(THF)1.25 (10). The reactions of 8 and 9 with triisobutyl aluminum in benzene- d6 show allyl exchange between lanthanide and aluminum. Complexes 8, 9, and 10 have been tested with a variety of activator systems as catalysts for the polymerization of 1,3-butadiene. [source] Indazaboles,synthesis and molecular structureAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 5 2010Bernd Wrackmeyer Abstract The reaction of 1-trimethylsilyl-indazole with boranes affords indazaboles accompanied by elimination of trimethysilane. Thus, the two isomers of parent indazabole are formed in a 1:1 ratio using borane in THF (BH3/THF), characterized by NMR spectroscopy in solution (1H, 11B and 13C NMR). In contrast, the analogous reaction with 1,2-bis(tetramethylene)diborane(6) proceeds to give a single isomer of the B-alkylated indazabole via symmetric ring cleavage of the diborane(6), as shown by NMR in solution and X-ray structural analysis in the solid state. The molecular structure is fluxional in solution. In the solid state, the central B2N4 ring adopts a distorted boat conformation. Calculated gas phase geometries of the parent indazaboles and of the B-alkylated indazabole were optimized by DFT methods at the B3LYP/6-311 + G(d,p) level of theory. Copyright © 2010 John Wiley & Sons, Ltd. [source] ChemInform Abstract: Synthesis and Transformations of 1-(Azidophenyl)-1H-tetrazoles.CHEMINFORM, Issue 39 2010N. T. Pokhodylo Abstract The cyclization of azide (IV) with cyanoacetanilide (VII) affords triazole derivative (VIII), whilst the analogous reaction with ethyl acetoacetate (V) is accompanied by cleavage of the tetrazole ring [some yields not given]. [source] The Reductive Elimination of Methane from ansa -Hydrido(methyl)metallocenes of Molybdenum and Tungsten: Application of Hammond's Postulate to Two-State ReactionsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 15 2005José-Luis Carreón-Macedo Abstract The energetic profile of the methane reductive elimination from a selected number of hydrido(methyl)molybdenocene and -tungstenocene derivatives has been calculated by DFT methods. The calculations were carried out for the CH2(C5H4)2M (a -M), SiH2(C5H4)2M (a -H2Si,M), and SiMe2(C5Me4)2M (a -Me2Si,M*) ansa -metallocene systems for M = Mo, W. They include the full optimization of minima [the hydrido(methyl) starting complexes, M(H)(CH3), the intermediate methane complexes, M(CH4), and the metallocene products in the singlet and triplet configurations, (3M and 1M)], transition states (for the methyl hydride reductive elimination, M,TSins, and for the hydrogen exchange, M,TSexch), and the minimum energy crossing point (M,MECP) leading from the singlet methane complexes to the corresponding triplet metallocenes. The results are compared with those previously obtained for the simpler (C5H5)2M (Cp2M) systems (J. C. Green, J. N. Harvey, and R. Poli, J. Chem. Soc., Dalton Trans.2002, 1861). The calculated energy profiles, notably the relative energies of M,TSins and M,MECP, are in agreement with available experimental observations for the a -Me2Si,M* systems. The comparison of the energies and geometries of the rate-determining M,TSins and M,MECP structures with those of the thermodynamically relevant minima for the various systems show the applicability of Hammond's postulate to two-state reactions. However, one notable exception serves to show that the principle is only quantitatively reliable when all the potential energy surfaces for the set of analogous reactions have similar shapes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Computational studies on the reactions of 3-butenyl and 3-butenylperoxy radicalsINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 5 2010Akira MiyoshiArticle first published online: 11 MAR 2010 The reactions of 3-butenyl (,CH2CH2CHCH2) radicals,unimolecular decomposition, isomerization, as well as reaction with O2,and the subsequent unimolecular rearrangement reactions of the 3-butenylperoxy radicals have been investigated and are compared to the analogous reactions of butyl (,CH2CH2CH2CH3) and butylperoxy radicals using transition-state theory based on the quantum chemical calculations at the CBS-QB3 level. For alkyl-analogue processes, the reactions of 3-butenyl and 3-butenylperoxy radicals can be well characterized by the decreased and increased bond dissociation energies at the allylic and vinylic sites, respectively. The intramolecular addition reactions of the radical center atoms to the double bonds were found to be important non-alkyl-analogue reactions of 3-butenyl and 3-butenylperoxy radicals. As a consequence, the thermal decomposition of 3-butenyl radicals was found to be slower than that of butyl radicals by one order of magnitude at temperature near 1000 K. Intramolecular addition reactions are suggested to be the predominant unimolecular rearrangement processes of 3-butenylperoxy radicals over the entire temperature range investigated (500,1200 K). The intramolecular addition reactions of the alkenyl peroxy radicals, which have not been included in combustion kinetic models, and their implications for the autoignition of alkenes are discussed. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 273,288, 2010 [source] Facile syntheses of homothia- and homoazacalixarenesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2000Kazuaki Ito Decahomotetrathiacalix[6]arenes were conveniently prepared from the 2:2 cyclization reactions of bis(chloromethyl)phenol-formaldehyde trimers with 1,2-ethanedithiol in high yields. In contrast, the simi lar reactions of the trimers with 1,3-propanedithiol instead of 1,2-ethanedithiol gave 1:1 macrocycles, hexahomodithiacalix[3]arenes, in good yields. Homoazacalixarenes were also prepared from the analogous reactions using piperazines. These macrocycles adopt a cone-like form as a preferable conformation in solution. [source] Synthesis of polymeric 1-iminopyridinium ylides as photoreactive polymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2010Daniel Klinger Abstract Two synthetic routes to polymeric 1-imino pyridinium ylides as new photoreactive polymeric architectures were investigated. In the first approach, polymerization of newly synthesized 1-imino pyridinium ylide containing monomers yielding their polymeric analogues was achieved by free radical polymerization. Alternatively, reactive precursor polymers were synthesized and converted into the respective 1-imino pyridinium ylide polymers by polymer analogous reactions on reactive precursor polymers. Quantitative conversion of the reactive groups was achieved with pentafluorophenyl ester containing polymers and newly synthesized photoreactive amines as well as by the reaction of poly(4-vinylbenzoyl azide) with a photoreactive alcohol. The polymers obtained by both routes were examined regarding their photoreaction products and kinetics in solution as well as in thin polymer films. Contact angle measurements of water on the polymer films before and after irradiation showed dramatic changes in the hydrophilicity of the polymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 832,844, 2010 [source] 4-Alkylphenoxymethyl-Substituted Polystyrenes for Liquid Crystal Alignment LayersMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 11 2009Hyo Kang Abstract We synthesized a phenoxymethyl-substituted polystyrene (PHP) and a series of 4-alkylphenoxymethyl-substituted polystyrenes, where the alkyl group is (CH2)nH (n,=,1, 2, 4, 6, and 8), using polymer analogous reactions, in order to study the effect of the phenoxymethyl and 4-alkylphenoxymethyl side groups on the liquid crystal (LC) alignment properties. The LC cell fabricated with the rubbed PHP film exhibited homogeneous planar and perpendicular LC alignment with respect to the rubbing direction. On the contrary, the LC cells made from the 4-alkylphenoxymethyl-substituted polystyrenes showed homeotropic LC alignment behaviors even at a very high rubbing density of 250, regardless of the length of the alkyl groups. Previously, n -alkylsulfonylmethyl-substituted polystyrenes with alkyl groups having more than 8 carbons (n,>,8) showed homeotropic LC alignment behavior. Therefore, the additional phenoxy group in the side chain was found to improve the homeotropic LC aligning ability of the polystyrene derivatives. [source] Multifunctional Polymethacrylates Obtained Via ATRP of Functional and Reactive Monomers Followed by Polymer Analogous Reaction with Functional AminesMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 19 2008Dragos Popescu Abstract Starting from methyl methacrylate (MMA), butyl methacrylate (BMA), allyl methacrylate (AMA), phenoxycarbonyloxy ethyl methacrylate (PCEMA), and functional amines different multifunctional polymethacrylates are accessible. The reactive monomer PCEMA was synthesized starting from 2-hydroxyethyl methacrylate, and then copolymerized via ATRP with other methacrylates in order to obtain reactive copolymers which were subjected to polymer analogous reactions with different functional amines leading to multifunctional polymethacrylates. These can be used for the preparation of multifunctional surfaces. [source] Liquid crystal alignment property of n -alkylthiomethyl- or n -alkylsulfonylmethyl-substituted polystyrenesPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009Hyo Kang Abstract We synthesized a series of n -alkylthiomethyl-substituted polystyrenes (#T-PS, #,=,4, 8, 12, and 16) and n -alkylsulfonylmethyl-substituted polystyrenes (#S-PS, #,=,4, 8, 12, and 16), where # is the number of carbon atoms in the n -alkyl side group of the polymers, using polymer analogous reactions to investigate their liquid crystal (LC) alignment properties. In general, the LC cell fabricated using the polymer film having a longer n -alkyl side group, a thioether linkage group, and a higher molar content of n -alkyl side group showed homeotropic LC alignment behavior with a pretilt angle of about 90°. The homeotropic alignment behavior was well correlated with the surface energy of the polymer films; when the positive dielectric anisotropic LC (ZLI-5900-000 from Merck) and negative dielectric anisotropic LC (MLC-7026-000 from Merck) were used to fabricate the LC cells, homeotropic alignment was observed when the surface energy values of the polymer were smaller than about 25 and 32,mJ/m2, respectively. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||