Optical properties of bis-(2,4,6-trimethylpyridine)iodine(I) cation: absorption and emission

With regard to its electronic structure, the cation Icoll₂⁺ (coll = collidine or 2,4,6-trimethylpyridine) is viewed as a coordination compound of iodine(I) with a p⁴ electron configuration. The lowest-energy excited state of Icoll₂⁺ is suggested to be a ππ^* collidine intraligand (IL) triplet which appears in absorption (λ_max=332 nm, ε=250) and emission (λ_max=405 nm, φ=0.001, τ∼90 ns). Owing to the heavy-atom effect of iodine this phosphorescence occurs at r.t. The longest-wavelength pp absorption is apparently obscured by the intense spin-allowed IL band at λ_max=268 nm.     

Condensation polymerization of bis-(salicylaldehydo) metal(II) with diamines

Summary Condensation of bis-(salicylaldehydo) metal (II) (metal = Be, Zn and Cd) and diamines (1,4-diaminobenzene or 4,4-diaminodiphenyl) yield polymeric complexes which have been investigated for their characteristics, composition, structure, thermal stability and polymeric nature. The stable, powdery solids obtained by refluxing 11 bis-(salicylaldehydo) metal-chelate (in DMF) and the diamine (ethanolic) have the composition (-ML-)_n and are insoluble in common organic solvents. I.R. study indicates that salicylaldehyde molecule is bonded to the metal ion through the oxygen atoms of phenolic and aldehydic groups in bis-(salicylaldehydo) metal-chelates. On interaction with the diamines, the polymeric complexes are formed, the nitrogen atoms of the amino groups replacing the aldehydic oxygens. The terminal nitrogens of the diamine, bridge two bis-(salicylaldehydo) metal-chelates, and the polymeric chain grows in a similar manner. The complexes obtained from 4, 4-diaminodiphenyl are thermally more stable than those from 1,4-diaminobenzene. The order of thermal stability of the polymers is : Be Zn>Cd.     

双(4-(对氟苯甲酰基)苯基)苯基氧化膦的合成与表征

以双(4-羧苯基)苯基氧化膦、氟苯等为原料,合成了标题化合物,并采用差示扫描量热法、红外光谱和核磁共振等对产品的结构进行了表征。     

Synthesis and biological activities of N-ferrocenylformyl-N'-aryl bis-(mono-) thiourea derivatives

二茂铁甲酰基异硫氰酸酯与对苯二胺、4,4’-二氨基二苯醚、4,4’-二氨基二苯甲烷、联苯胺反应,合成了一类新型的N-二茂铁甲酰基-N’-芳基硫脲类衍生物,其中包括4种双酰基硫脲衍生物和4种单硫脲类衍生物.通过元素分析、IR、1HNMR的测定确证了其结构.初步生物活性测试结果表明,部分化合物具有一定的生长调节活性.     

Solubility and diffusivity of bis-(2-chloroethyl)-sulfide in polypropylene

Solubility and diffusivity have been determined for bis-(2-chloroethyl)sulfide in isotactic polypropylene at temperatures from 15 to 40°C and relative pressures from 0.34 to 1.00. While the solubility in films annealed above 90°C followed the normal variation with the amorphous content, the quenched film had a significantly lower amorphous volume fraction than determined from its density, 46 instead of 60%. The diffusion behavior in the film was found to be invariably Fickian and not dependent on the amorphous volume fraction of the polymer between 0.34 and 0.46. The solubility was found to be independent of the temperature over the range 15–40°C, but dependent on the diffusant concentration. The isotherms were well represented by the Flory-Huggins relation for crosslinked polymers, and values for the interaction constant and the average molecular weight between crystallites have been obtained. The value of the interaction constant, μ = 1.13, is an expression of the low affinity bis-(2-chloroethyl)sulfide has for polypropylene. The intrinsic diffusivity was only weakly dependent on the diffusant concentration. The results were found to be in agreement with Fujita's free-volume theory. The apparent activation energy for the diffusion of bis(2-chloroethyl)sulfide in isotactic polypropylene was found to be 22.5 kcal/mol.     

Study of diffusion and sorption of bis-(2-chloroethyl)sulfide (SM) and bis-(2-chloroethyl)ether (OM) through polypropylene (PP) and biaxial-oriented polypropylene (bopp) films by the FTIR–ATR spectroscopic method

The diffusion of sulfur mustard (SM) and oxygen mustard (OM) in polypropylene (PP) and biaxial-oriented PP (BOPP) was measured using Fourier transform infrared–attenuated total reflectance (FTIR–ATR) spectroscopy, which allows one to study the diffusion of liquid through thin polymer films in situ. The temperature-dependent diffusion coefficients of OM and SM for PP and BOPP are also reported; these are in good agreement with the values obtained by the weight gain method. The activation energy of diffusion is determined by both methods. The polymer–penetrant interaction parameter (K) and transport number (n) are calculated for the system PP/OM and BOPP/OM by weight gain method. The “n” values indicate a Fickian mode of diffusion. © 1996 John Wiley & Sons, Inc.     

Homogeneous catalysis of the reduction of nitrobenzene by bromotris(triphenylphosphine) copper (I)

Homogeneous reduction of nitrobenzene by hydrogen in presence of complex [Cu^IBr(PPh₃)₃] as catalyst has been investigated. From a study of various operational parameters, it has been observed that maximum reduction occurred at 2.5 × 10³ kPa pressure and at 473–513 K and resulted in 75% aniline, 10% azobenzene, 2% nitrosobenzene in ethanol, and 70% aniline, 5% azobenzene, 7% nitrosobenzene in dimethylformamide, calculated on the basis of input nitrobenzene. In an attempt to elucidate the reduction mechanism two new intermediates, [CuHPPh₃Br]₂ (I) and [(C₆H₅N=NC₆H₅)Cu₂(PPh₃)₄Br₂] (II), have been isolated and characterised by elemental analysis, spectral, thermal, magnetic and p.m.r. studies.     

Cross-linking reactions on polyamides by bis- and tris(maleimide)s

12 bis- and tris(maleimide)s were synthesized and characterized and their reactions with polyamides in the melt were examined. It was found that the double bonds of the maleimides react with terminal amino groups of the polyamides to form elastomeric networks. The chemical and physical properties of these elastomers were examined. Mixtures of bis- and tris(maleimide)s with amino-terminated polyamides can be applied as hot melt adhesives with high tensile and shear strength, with high thermal stability and high chemical resistance.     

联氢化嘧啶衍生物的合成及其构象研究

报道了一种合成联氢化嘧啶衍生物１￣５、四氮杂全氢芴衍生物６和７的新方法。讨论了化合物１￣５的稳定构象,提出了化合物５和７的顺反异构体的酸催化下的转变机理。     

一锅法制备含硫硅烷偶联剂TESPT

利用歧化和缩合反应原理,采用相转移催化一锅法将原料氢氧化钠、硫磺和γ-氯丙基三乙氧基硅烷制备成双-3-(三乙氧基硅烷)丙基四硫化物,考察了原料配比、氢氧化钠浓度、滴加方式及催化剂等对产品质量及收率的影响。结果表明,优化工艺条件为:氢氧化钠∶硫磺∶γ-氯丙基三乙氧基硅烷质量比为1.00∶1.33∶4.06,氢氧化钠浓度为25%,以2%四丁基氯化铵复配季铵盐作催化剂,歧化反应温度70℃,反应时间50 min,缩合反应温度85℃,滴加γ-氯丙基三乙氧基硅烷1 h,在此条件下,产率95.6%,硫含量为22.7%。     

二(2-羟基)乙基四硫的合成研究

以一氯化硫和2-巯基乙醇为原料,石油醚作溶剂,在0℃下4h内经缩合合成了二(2-羟基)乙基四硫,选取最佳条件n(2-巯基乙醇)：n(一氯化硫)=3,产率达到91．7％,产品纯度为91．1％．通过液相色谱、核磁共振谱和红外光谱等确定产品结构为二(2-羟基)乙基四硫。     

Preparation and Characterization of Polyester Based on bis- (2- hydroxypropyl terephthalate)

Polyester based on bis- (2-hydroxypropyl terephthalate) (BHPT) and maleic anhydride (MA) was prepared and its structure confirmed by spectral analysis. The kinetic of the condensation reaction was investigated at three different temperatures (180–200°C) in the presence and the absence of p-toluene sulphonic acid (PTSA) as a catalyst. The reaction order was found to be second and third order in the presence and absence of the catalyst, respectively. The activation energy was calculated in both cases and was found to be 15.7 and 145.5 kJ mol^–1 in the presence and absence of the catalyst, respectively. The polyester was mixed with styrene monomer, and with methyl ethyl ketone peroxide (0.5 wt.%) as initiator and cobalt naphthenate (0.25 wt.%) as accelerator to obtain a styrenated resin with good mechanical properties. N-phenyl maleimide (NPMI) was also used together with styrene in different ratios to form a copolymer. No pronounced improvement in the mechanical and the thermal properties was found after the introduction of NPMI.     

Selective hydrogenation with tris(triphenylphosphine) chlororhodium (I) catalyst: Preparation of octadecenoate isomers

Fractionation of products obtained from partial catalytic hydrogenation of methylcis-9,cis-12-octadecadienoate (9c,12c-18:2) with tris(triphenylphosphine) chlororhodium [RhCl(Ph₃P)₃] provided a facile method for preparation of a nearly equal molar mixture of methylcis-9- andcis-12-octadecenoate (9c-18∶1 and 12c-18∶1). Isolation of products was achieved by silver resin and C18 reverse phase liquid chromatography. Catalytic deuteration of 9c,12c-18∶2 yields a mixture of 9c-18∶1-12,13-d₂ and 12c-18∶1-9,10-d₂ with an isotopic purity of 85%. Final isolated yield of the mixture of 9c- and 12c-18∶1 products was 30%. Isolation of products from partial hydrogenation of conjugated octadecadienoates (9c,11t-18∶2 or 10t,12c-18∶2) provided a convenient method for synthesis of an almost equal molar mixture of methyltrans-10 andtrans-11-octadecenoate (10t-18∶1 and 11t-18∶1). Characterization of the reaction products from hydrogenation of 9c,12c-28∶2 indicates that the 9c- and 12c-18∶1 products are formed by the expected 1,2-hydride addition. The presence of small amounts of 10t- and 11t-18∶1 and conjugated octadecadienoates was evidence for a secondary isomerization-1,4-hydride addition pathway. Isolation and characterization of products from RhCl(Ph₃P)₃-catalyzed hydrogenation of 9c,11t-18∶2 and 10t,12c-18∶2 indicate that both 1,2- and 1,4-hydride addition to the conjugated diene isomers occurs at about equal rates, but only thecis bond is reduced by the 1,2-hydride addition pathway and the 1,4-hydride addition pathway yields only atrans-18∶1. Because of this unusual selectivity for acis bond conjugated with atrans bond, hydrogenation of both 9c,11t-18∶2 and 10t,12c-18∶2 yields the same mixture of t-18∶1 isomers.     

Photochemistry of trichloro(phenylazo)bis(triphenylphosphine)ruthenium(II) induced by Ru to phenyldiazonium MLCT excitation

The complex trichloro(phenylazo)bis(triphenylphosphine)ruthenium(II) shows a longest-wavelength absorption at λ_max = 520 nm which is assigned to a Ru(II) → phenyldiazonium⁺ MLCT transition. MLCT excitation leads to the oxidation of the metal and reduction of the diazonium cation which decays to nitrogen and phenyl radical.     

Conjugation of polyunsaturated fats: Methyl linoleate with tris(triphenylphosphine) chlororhodium

Tris(triphenylphosphine) chlororhodium in methanol produces nearly 95% conjugated dienes from methyl linoleate. The dienes are principally cis,trans- and cis,cis-conjugated. Since deuterium is introduced into the products when deuterated methanol is the solvent, a dihydride complex is the probable intermediate. The reaction is sluggish in chloroform, possible because the dihydride cannot easily form. The catalyst is activated in chloroform with hydrogen. Since no reduction occurs in the absence of hydrogen, hydrogenation likely occurs by hydrogenolysis of the alkyl complex of the dihydride olefin rather than a transfer of both hydrogens from the hydride complex. Presented at the AOCS Meeting, New Orleans, April 1970. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Absorption and emission spectra of Eu3 doped Fluoroborate glasses

This paper reports the preparation of certain newly developed Eu³⁺ - doped fluoroborate glasses with H₃BO₃ and Na₂CO₃ as the network formers (NWF) and the fluorides of alkali (Na or Li) as the network intermediates (NWL). Further, by adding AIF₃ to the fluoroborate glasses, properties such as glass transparency; hardness; resistivity towards moisture and IR-transmission ability were found improved significantly. Under a UV source, these colourless Eu³⁺ - glasses did reveal brighter red emission. Compositional effects on the absorption and photoluminescence spectra of Eu: fluoroborate glasses were examined from their measured spectrophotometric profiles.     

5,6—二（4—乙氧基苯胺）—2,3—二氰吡嗪的合成

合成了５,６－二（４－乙氧基苯胺）－２,３－二氰吡嗪,通过元素分析,ＩＲ,＾ＨＮＭＲ,ＭＳ分析证实其结构,并对其反应条件进行了探索。     

新型无卤阻燃剂新戊二醇双磷酸二苯酯的合成研究

报道了一种新型双磷酸酯阻燃剂———新戊二醇双磷酸二苯酯(NDP)的合成方法。采用氯化磷酸二苯酯(DPCP)和新戊二醇(NPG)为原料,以4-二甲氨基吡啶(DMAP)为催化剂,成功合成了NDP,并考察了溶剂、原料配比、反应温度、反应时间、催化剂用量等因素对反应收率的影响。反应的最佳条件为:以正己烷为溶剂,DPCP和NPG的摩尔比为2∶1,在0—5℃下反应12 h,DMAP与DPCP的质量比为5.3%,反应收率可达89.1%。经核磁、红外表征证明产品结构正确。热分析表明产品的热稳定性好,其分解可分为2个阶段:第1阶段在290℃左右,此时分解速度最快,在400℃仍有18.03%的质量残余;第2阶段热分解出现在717℃左右。