2,4,6-三甲基-1,3,5-苯三甲醛的合成与表征

以均三甲苯为初始原料,经氯甲基化、改进的Sommelet反应两步合成了目标产物2,4,6-三甲基-1,3,5-苯三甲醛。利用1H NMR、13C NMR等手段对各步所得产物的结构进行了表征,分析数据证实目标产物为2,4,6-三甲基-1,3,5-苯三甲醛。以均三甲苯计,两步反应的总收率为77.7%。     

Ion/molecule reactions provide new evidence for the structure and origin of

Ion/molecule reactions leading to formation of the diagnostically useful [C(3)H(4)N](+) ion (m/z 54), from acetonitrile CI plasma, have been studied using a tandem quadrupole mass spectrometer. Evidence is presented to demonstrate that [C(3)H(4)N](+) is produced from an ion/molecule reaction between [C(2)H(2)N](+) (m/z 40) and neutral acetonitrile, via a [C(4)H(5)N(2)](+) (m/z 81) intermediate. Loss of HCN, where the H atom arises from neutral acetonitrile and the CN group from [C(2)H(2)N](+) (m/z 40), leads to the production of [C(3)H(4)N](+) (m/z 54). These results are consistent with a proposed concerted elimination of HCN, generating m/z 54 as a methylene vinylidene ammonium ion. Copyright 1999 John Wiley & Sons, Ltd.     

Spectroscopic study on the intermolecular double proton transfer in 4-(naphthalen-1-yl)-6-octyl-1,3,5-triazin-2-amine with acid

With 2,4,6-trichloro-1,3,5-triazine as starting material, a functionalized triazine derivative, 4-(naphthalen-1-yl)-6-octyl-1,3,5-triazin-2-amine (NOTA) was synthesized in 14% yield through three steps: Kumada cross-coupling, Suzuki coupling and amination. Intermolecular double proton transfer of NOTA with acetic acid (HOAc) and trifluoroacetic acid (TFA) in chloroform was investigated by UV–vis absorption and fluorescence emission. It is found that both NOTA/HOAc and NOTA/TFA undergo excited state double proton transfer, resulting in amino–imino tautomerization emission in excited state.     

Thermal decomposition of 2,4,6-triazido-1,3,5-triazine

The thermal decomposition of 2,4,6-triazido-1,3,5-triazine in the melt and a dinonyl phthalate solution is studied by thermogravimetry, manometry, mass spectrometry, and IR spectroscopy. The kinetic and activation parameters of the process are determined. The only gaseous product of the reaction is nitrogen. This fact, along with the structure of the condensed residue formed during the thermal decomposition of 2,4,6-triazido-1,3,5-triazine in the melt, are indicative of the abstraction of a nitrogen molecule from an azide group at the initial stage and of the subsequent reactions leading to the formation of a planar network of polyconjugated bonds between C and N atoms. For the thermal decomposition of 2,4,6-triazido-1,3,5-triazine in solution the preexponential factor and activation energy are found to be 10^12.8 s^–1 and 34100 cal/mol, respectively, which are characteristic of the thermal decomposition of most azides. To explain why these parameters are substantially higher for the reaction in the melt (10^17.4 s^–1 and 42300 cal/mol), it is assumed that, in this case, the process proceeds by the polymerization (polycondensation) mechanism to form twodimensional networks, with the apparent kinetic parameters being effective quantities. Based on these data, it is concluded that the high sensitivity of 2,4,6-triazido-1,3,5-triazine to external influences is of kinetic nature.     

Differentiation of aminomethyl corrole isomers by mass spectrometry

Two new isomeric aminomethyl corrole derivatives of [5,10,15-tris(pentafluorophenyl)corrolato]gallium(III) were synthesized with pyridine (py) molecules as axial ligands. When investigated by electrospray ionization mass spectrometry, in the positive and the negative ion modes, these compounds showed an unusual gas-phase behavior that could be used for their differentiation. In the positive ion mode, the differentiation was achieved through the formation of diagnostic fragment ions formed from [M-py?+?H](+) precursors, by (CH(3) )(2) NH and HF losses. An unusual addition of water to the main fragment ions provides an alternative route for isomer identification. Semi-empirical calculations were performed to elucidate the structures and stabilities of the main ionic species formed in the positive ion mode. In the negative ion mode isomer discrimination is accomplished via the fragmentation of the methoxide adduct ions [M-py?+?CH(3) O](-) through (CH(3) )(2) N(.) and HF losses.     

Evidence for the development of persistent carbon-centered radicals from a benzyl phenolic antioxidant: an electron paramagnetic resonance study

Radicals have been generated from the benzyl phenolic antioxidant 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl) benzene, carrying out oxidative and hydrogen abstraction reactions. Transient phenoxyl radicals were directly visualized but only persistent carbon-centered radicals were monitored by electron paramagnetic resonance (EPR). The experimental EPR results let us rationalize our analysis as the sum of two different radicals. One, called the methylene radical, developed from the loss of a benzylic hydrogen gave place to a doublet of triplets witha _CH^H≅2.7 mT anda _PH^H=0.165 mT. Besides, the methyl radical, developed after an intramolecular hydrogen transfer involving a methyl group on the central aromatic ring of the molecule, formed a triplet of triplets, witha ₁^H around 0.060 mT anda ₂^H=0.169 mT. All the contact interactions were tested by EPR simulation of the experimental data.     

Nondestructive room-temperature adsorption of 2,4,6-tri(2'-thienyl)-1,3,5-triazine on a Si-B interface: high-resolution STM imaging and molecular modeling

Organic nanostructures on semiconductors are currently investigated but the surfaces are known to interact strongly with molecules. To reduce the molecule-surface interaction, we used the Si(111)-B square root 3 x square root 3R30 degrees . Deposition of isolated 2,4,6-tri(2'-thienyl)-1,3,5-triazine, was achieved at room temperature without modification of their pi skeleton. This fascinating arrangement, observed by STM, has been validated by full density functional theory computations onto the entire system. The theoretical results give a clear explanation for the specific adsorption sites of molecules on the substrate.     

Quantification and remote detection of nitro explosives by helium plasma ionization mass spectrometry (HePI-MS) on a modified atmospheric pressure source designed for electrospray ionization

Helium Plasma Ionization (HePI) generates gaseous negative ions upon exposure of vapors emanating from organic nitro compounds. A simple adaptation converts any electrospray ionization source to a HePI source by passing helium through the sample delivery metal capillary held at a negative potential. Compared with the demands of other He-requiring ambient pressure ionization sources, the consumption of helium by the HePI source is minimal (20-30?ml/min). Quantification experiments conducted by exposing solid deposits to a HePI source revealed that 1?ng of 2,4,6-trinitrotoluene (TNT) on a filter paper (about 0.01?ng/mm(2)) could be detected by this method. When vapor emanating from a 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) sample was subjected to helium plasma ionization mass spectrometry (HePI-MS), a peak was observed at m/z 268 for (RDX●NO(2))(-). This facile formation of NO(2)(-) adducts was noted without the need of any extra additives as dopants. Quantitative evaluations showed RDX detection by HePI-MS to be linear over at least three orders of magnitude. TNT samples placed even 5?m away from the source were detected when the sample headspace vapor was swept by a stream of argon or nitrogen and delivered to the helium plasma ion source via a metal tube. Among the tubing materials investigated, stainless steel showed the best performance for sample delivery. A system with a copper tube, and air as the carrier gas, for example, failed to deliver any detectable amount of TNT to the source. In fact, passing over hot copper appears to be a practical way of removing TNT or other nitroaromatics from ambient air.     

Thermal decomposition of 2,4-diazido-6-trinitromethyl-1,3,5-triazine, 2,4-dimethoxy-6-trinitromethyl-1,3,5-triazine,and 2,4-diazido-6-methoxy-1,3,5-triazine

The thermal decomposition of 2,4-diazido-6-trinitromethyl-1,3,5-triazine, 2,4-dimethoxy-6-trinitromethyl-1,3,5-triazine, and 2,4-diazido-6-methoxy-1,3,5-triazine in a melt was studied by differential scanning calorimetry, thermogravimetry, manometry, mass spectrometry, and IR spectroscopy. The kinetics of these reactions was investigated, and the activation parameters were determined. The gaseous products of the decomposition of 6-trinitromethyl-2,4-diazido-1,3,5-triazine were N₂, NO, N₂O, CO, and CO₂ in a molar ratio of 1: 2: 1: 0.6: 1 and pronounced amounts of NO₂. A comparison of kinetic data for the compounds under study indicated that the azide groups in 2,4-diazido-6-trinitromethyl-1,3,5-triazine were thermally more stable than the trinitromethyl group.     

Analysis of cyclic boronated and trimethylsilylated phenolalkylamines by gas chromatography and electron impact mass spectrometry

The side chain of phenolalkylamines containing a bifunctional group was derivatized as the cyclic boronate, and then the residual phenolic group was trimethylsilylated. The resulting derivatives were single reaction products in each case, with good gas chromatographic properties and informative mass spectra to afford prominent molecular ions by gas chromatography with electron impact mass spectrometry (GC/EI-MS). The cyclic boronated-trimethylsilylated derivatives yielded the isotope pattern for boron ((10)B:(11)B =-1:4.2) and characteristic ions [M](+), [M - H](+), [M - CH(3)](+), [M - RBO](+), [M - TMSO](+), and [M - TMSO - C(6)H(5)](+) ions in the mass spectra. In order to distinguish between m- and p-phenolalkylamines, the mass spectra of the cyclic phenylboronated-trimethylsilylated (PBA-TMS) derivatives were compared with those of the trimethylsilylated (TMS) derivatives. The TMS derivatives of octopamine (p-) and norfenefrine (m-) showed identical mass spectra, while the PBA-TMS derivatives had mass spectra sufficiently different from one other to distinguish between the isomers. The most prominent ion of the PBA-TMS derivative is the [M - H](+) ion (m/z 310) for octopamine and the [M](+) ion (m/z 311) for norfenefrine. Copyright 1999 John Wiley & Sons, Ltd.     

5-乙酰(苯甲酰)基-4-芳基-3,4-二氢嘧啶-2(1H)-酮的质谱裂解规律

利用飞行时间质谱仪的高分辨本领和离子阱串联质谱技术研究了5乙酰(苯甲酰)基4芳基3,4二氢嘧啶2(1H)酮(1-5)的电子轰击质谱的裂解规律.将所有质谱离子的精确质量数据经OpenLynx软件导出其分子离子和碎片离子的元素组成.根据质谱裂解规律,主要质谱离子得到了归属,并经离子阱串联质谱技术加以证实.化合物1-3的质谱出现了丰度很强的分子离子峰,其中1和3的分子离子为基峰,证明此类化合物的结构相当稳定.但4和5的分子离子峰却很弱(相对丰度在4%以下),这是由于嘧啶环4位上的苯环分别含有强吸电子基团-NO2(在苯环的间位才有此效应)和-Cl(苯环的2和4位均含有氯)所致.化合物1-5的主要裂解包括:分子离子失去芳基形成丰度很高的阳离子(M-Ar)+;分子离子失去羰基形成中等强度的阳离子(M-RCO)+;分子离子失去氢原子所产生的(M-H)+峰,以及消除中性分子NH=C=X的嘧啶环破裂裂解.此外,所有化合物在低质量区都发现明显的苯基阳离子Ph+(m/z77).并且还提出个别化合物的几个额外裂解过程为:化合物4(分子中苯环的3位上含有硝基)出现的基峰(M-OH)+;化合物5(分子中苯环的2和4位上都含有氯原子)出现了的基峰(M-Cl)+;化合物3和5分别出现了m/z238(16%)和m/z241(29%)的特征离子峰,它们由相应的离子消除中性分子四员内酰胺生成查耳酮离子,该离子具有共轭大Π键而稳定存在.     

Intramolecular proton transfers in stereoisomeric gas-phase ions and the kinetic nature of the protonation process upon chemical ionization

The isobutane chemical ionization (CI) mass spectra of cis- and trans-1-butyl-3- and -4-dimethylaminocyclohexanols and of their methyl ethers exhibit abundant [MH - H(2)O](+) and [MH - MeOH](+) ions respectively. On the other hand, only the MH(+) ions of the cis-isomers exhibit significant [MH - H(2)O](+) and [MH - MeOH](+) ions under collision-induced dissociation (CID) conditions. The non-occurrence of water and methanol elimination in the CID spectra of the trans-isomers indicates retention of the external proton at the dimethylamino group in the MH(+) ions that survive after leaving the ion source and the first quadrupole of the triple-stage quadrupole ion separating system, and the trans-orientation of the two basic sites does not allow proton transfer from the dimethylamino group to the hydroxyl or methoxyl. Such transfer is allowed in the cis-amino alcohols and amino ethers via internal hydrogen-bonded (proton-bridged) structures, resulting in the elimination of water and methanol from the surviving MH(+) ions of these particular stereoisomers upon CID. The abundant [MH - ROH](+) ions in the isobutane-CI mass spectra of the trans-isomers indicates protonation at both basic sites, affording two isomeric MH(+) ions in each case, one protonated at the dimethylamino group and the other at the less basic oxygen function. These results show that the isobutane-CI protonation of the amino ethers and amino alcohols is a kinetically controlled process, occurring competitively at both basic sites of the molecules, despite the large difference between their proton affinities ( approximately 25 and approximately 35 kcal mol(-1); 1 kcal = 4.184 kJ). Copyright 1999 John Wiley & Sons, Ltd.     

Gas phase retro-Michael reaction resulting from dissociative protonation: fragmentation of protonated warfarin in mass spectrometry

A mass spectrometric study of protonated warfarin and its derivatives (compounds 1 to 5) has been performed. Losses of a substituted benzylideneacetone and a 4-hydroxycoumarin have been observed as a result of retro-Michael reaction. The added proton is initially localized between the two carbonyl oxygens through hydrogen bonding in the most thermodynamically favorable tautomer. Upon collisional activation, the added proton migrates to the C-3 of 4-hydroxycoumarin, which is called the dissociative protonation site, leading to the formation of the intermediate ion-neutral complex (INC). Within the INC, further proton transfer gives rise to a proton-bound complex. The cleavage of one hydrogen bond of the proton-bound complex produces the protonated 4-hydroxycoumarin, while the separation of the other hydrogen bond gives rise to the protonated benzylideneacetone. Theoretical calculations indicate that the 1, 5-proton transfer pathway is most thermodynamically favorable and support the existence of the INC. Both substituent effect and the kinetic method were utilized for explaining the relative abundances of protonated 4-hydroxycoumarin and protonated benzylideneacetone derivative. For monosubstituted warfarins, the electron-donating substituents favor the generation of protonated substituted benzylideneacetone, whereas the electron-withdrawing groups favor the formation of protonated 4-hydroxycoumarin. Copyright ? 2012 John Wiley & Sons, Ltd.     

稀土配合物RE(TPTZ)Cl_3的合成、表征及荧光性能研究

首次以2,4,6-三吡啶基三嗪（TPTZ）与Sm, Eu, Tb和Dy氯化物反应,合成四种单一稀土配合物以及Tb分别1∶1掺Gd, Y, La的三种异核配合物。经元素分析、稀土络合滴定、摩尔电导率、红外光谱、紫外光谱和差热-热重测定表明,配合物的组成分别为RE（TPTZ）Cl3·3H2O（RE=Sm, Eu, Tb, Dy）和Tb0.5Ln0.5（TPTZ）Cl3·3H2O（Ln=Gd, Y, La）;TPTZ作为三齿配体与稀土离子配位,即中心环提供一个N原子,两个吡啶环分别提供一个N原子;配合物中3个水分子与稀土离子配位,1个Cl-在外界,2个在内界,为1∶1型电解质;配合物内外界可能为[RE（TPTZ）（H2O）3Cl2] Cl,稀土离子的配位数为8。配合物的荧光光谱测试表明,四种单一稀土配合物中,Tb配合物发光最强;三种1∶1掺杂异核Tb配合物荧光强度大于纯Tb配合物,表明Y3＋, La3＋和Gd3＋都可以敏化Tb3＋的发光,其中Gd3＋的敏化作用最强,Y3＋次之,La3＋最差。     

Two New Coordination Polymers: Selective Detection of Cu(II) Ion and Treatment Activity on Inner Ear Damage

Journal of Fluorescence - In the current study, on the basis of 1,3,5-tris(2-methylimidazol-1-yl)benzene (timb), a designed tripodal connector, two new transition metal coordination polymers (CPs),...     

Novel Stilbene-triazine Symmetrical Optical Brighteners: Synthesis and Applications

A series of new high light fastness, hot pressing fastness optical brighteners was efficiently synthesized by a three-step approach involving the successive replacement of the three chloro groups of 2,4,6-trichloro-1,3,5-triazine under different conditions of temperature and pH. Thus, 2,4,6-trichloro-1,3,5-triazine was treated with different anilines and the resulting dichlorotriazinyl intermediates (3a-I) were further condensed with 4,4-diaminostilbene-2,2′-disulfonic acid to afford bis-monochlorotriazine (5a-I) followed by nucleophilic substitution with ethanolamine to furnish the final hybrid brighteners (7a-I). All of the newly synthesized compounds were characterized by Fourier-Transform Infrared (FT-IR), UV-visible absorption, NMR spectroscopy and the elemental analyses. The synthesized optical brighteners were also assessed for their efficacy as fluorescent brightening agents.     

2-Amino-5-(4-pyridinyl)-1,3,4-thiadiazole film at the silver surface: Observation by Raman spectroscopy and electrochemical methods

Surface enhanced Raman scattering (SERS) spectrum of the 2-amino-5-(4-pyridinyl)-1,3,4-thiadiazole (4-APTD) on the silver surface was recorded and assigned with the help of B3LYP/6-311G** method. SERS result explored that 4-APTD molecule with a tilted orientation anchored at the silver surface via N¹², S¹ and C² atoms. In situ SERS spectroelectrochemical experiment indicated 4-APTD molecule experienced an intermediate adsorption process of its thiadiazole ring moiety with the vertical orientation at the surface before the 4-APTD molecule detached completely from the surface as the potential applied at −1.3 V vs. SCE. Electrochemical impedance spectroscopy (EIS) and polarization experiments exhibited the sound anticorrosive effect of the 4-APTD film on silver surface with an efficiency of 89.5%.     

2,4,6-三吡啶基三嗪-芳香羧酸镝配合物的合成及其荧光性能

分别以2,4,6-三吡啶基三嗪( TPTZ)、对羟基苯甲酸和对苯二甲酸为配体,以Dy3+为中心合成了不同组成的5种配合物.对其进行了元素分析、紫外光谱、红外光谱、荧光激发和发射光谱的测定.推测配合物的组成分别为:(1)Dy(TPTZ)(NO3)3(C2H5OH)·H2O; (2) Dy (TPTZ)2 (NO3)3 (...     

Metal Complexation Properties of Schiff Bases Containing 1,3,5-Triazine Derived from 2-Hydroxy-1-Naphthaldehyde in Solution. A Simple Spectrofluorimetric Method to Determine Mercury (II)

Four new Schiff base ligands carrying naphthalene groups were prepared from the reaction of 2,4-diamino-6-methyl-1,3,5-triazine and 2,4-diamino-6-undecyl-1,3,5-triazine with 2-hydroxy-1-naphthaldehyde. The influence of a series of metal ions including Cu²⁺, Co²⁺, Hg²⁺, Al³⁺, Cr³⁺, Fe³⁺, Pb²⁺, Ni²⁺, Cd²⁺, Zn²⁺, Mn²⁺, Ag⁺, Ba²⁺, Ca²⁺ and Mg²⁺ on the spectroscopic properties of the ligands was investigated by means of absorption and emission spectrometry. The results of spectrophotometric and spectrofluorimetric titrations disclosed the complexation stoichiometry and complex stability constant of the ligands with metal ions. A simple spectrofluorimetric method was developed using the Schiff base derived from 2,4-diamino-6-undecyl-1,3,5-triazine to determine Hg²⁺ ion. No cleanup or enrichment of the tap water sample was required. A modified standard addition method was used to eliminate matrix effect. The standard addition graph was linear between 0.2 and 2.6 mg/L in determination of Hg²⁺. Detection and quantification limits were 0.08 and 0.23 mg/L, respectively. The simple and cost-effective method can be applied to water samples.     

Triphenylbenzene Sensor for Selective Detection of Picric Acid

A C ₃-symmetric triphenylbenzene based photoluminescent compound, 1,3,5-tris(4′-(N-methylamino)phenyl) benzene ([NHMe]₃TAPB), has been synthesized by mono-N-methylation of 1,3,5-tris(4′-aminophenyl) benzene (TAPB) and structurally characterized. [NHMe]₃TAPB acts as a selective fluorescent sensor for picric acid (PA) with a detection limit as low as 2.25 ppm at a signal to noise ratio of 3. Other related analytes (i.e. TNT, DNT and DNB) show very little effect on the fluorescence intensity of [NHMe]₃TAPB. The selectivity is triggered by proton transfer from picric acid to the fluorophore and ground-state complex formation between the protonated fluorophore and picrate anion through hydrogen bonding interactions. The fluorescence lifetime measurements reveal static nature of fluorescence quenching.