含羧基的三核钨原子簇化合物的研究——Ⅰ.(Me_4N)[W_3(μ_3-O)(μ-Cl)_3(μ-HCOO)_3Cl_3]的合成和分子结构

用两种方法合成了标题化合物。晶体属正交晶系,空间群为Pnma,a=12.043(1),b=11.521(1),c=14.137(2)(?),V=1961.6(?)~3,Z=4,D_c=3.35g·cm~(-3),M=989.47,F(000)=1776,μ=194.06cm~(-1)。最终的R因子为0.064。簇阴离子的簇骼为W_3OCl_3,这是一个缺顶点的类立方烷构型。     

表面活性剂特性吸附对增强光敏分子固体为基极的光伏打效应的影响

卟啉类的光电极在分子固体液体接界光伏打电池工作中已得到研究。本文用阴离子型表面活性剂在固体表面上的特性吸附等温线来分析此种离子浓度对数函数与光伏打效应增长的关系,并研究了表面活性剂烷基链长、极性基、阳离子型表面活性剂及非离子型表面活性剂对光伏打效应增强的影响。内Helmholtz层结构与参量变化对光伏打效应也起重要作用。     

分子结构对聚酰亚胺膜分离CO_2/CH_4性能的影响

气体在致密高分子膜中的渗透过程与高分子的链段活动性和自由体积有关,高分子的链段活动性越大,气体的扩散越容易,气体的透过速度越快,高分子自由体积增大,气体的溶解系数增大,扩散速率加快,透气速率上升．因此,为了得到高选择性和高透气性的分离膜,可对其化学结...     

催化剂对基团转移聚合的影响

本文研究了催化剂的种类和用量对硅烯醚型引发剂引发的基团转移聚合的影响。发现四丁基二苯甲酸氢铵(Bu_4NH(C_6H_5CO_2)_2,TBABB)和HsI_2的催化效果较好。只需引发剂的4％的HgI_2即可使MMA的基团转移聚合达到完全转化。认为有效的氧负离子催化剂应由较稳定的铵正离子和电负性较大的氧负离子所组成。过量的催化剂不利于基团转移聚合的进行。考察了TBABB催化剂对温度的依赖性及其浓度对聚合速率,分子量和分子量分布,转化率的影响。     

THE EFFECT OF IRRADIATION ON THE POLYETHERKETONE WITH CARDO GROUP

The effects of irradiation on the polyetherketone with cardo group (PEK-C) were studied. It was found that PEK-C can be crosslinked by irradiation under vacuum, while degradation reaction occurred in PEK-C at room temperature in the presence of air. Moreover. it was also found that Ts value of the crosslinked PEK-C at high temperature is higher than that at room temperature in the case of the same gel content, whose value is about 8℃higher than that of unirradiated PEK-C. The gelation dose of PEK-C at 300℃under vacuum is 1.5×10~4 Gy, which is about hundred times smaller than that at room temperature.     

介电法研究溶液中分子间的缔合作用(I)

磷酸三丁酯(TBP)是一种重要的萃取剂,它已广泛地应用于许多金属的提取工艺中。在萃取过程中,水在两相间的转移对萃取过程产生重要影响。一些实验表明,TBP分子是通过氢键与水生成1∶1缔合物形式萃取水分子。但对该缔合物的物理化学性质研究尚未见报导。我们运用静态介电研究法,通过测定溶液介电常数,并应用向无限稀释外推手段,进一步证明TBP与H_2O的缔合作用,并测得TBP·H_2O缔合物的摩尔极化度、偶极矩和缔合平衡常数,进而求得缔合反应的自由能。     

聚甲基丙烯酸甲酯的分子量对温度-形变性质的影响

本文从的简化分子模型出发,改进了分子量和T_f间的关系式,得到了lnM=A-E/R·1/T_f的直线方程。对于分级的聚甲基丙烯酸甲酯的冷压和热压样品进行了不同荷重下温度-形变性貭的研究,所有的结果均符合上述方程式。本文并讨论了样品成型,施加荷重的大小等因素对聚合物温度-形变性貭的影响。     

分子端基效应对聚(L-乳酸)球晶环带结构形成的影响

通过活性正离子开环聚合的方法,以苯甲醇或月桂胺引发L-丙交酯聚合合成了一系列分子量可控的聚(L-乳酸)(PLLA).研究发现,端基刚、柔性的变化,改变了PLLA环带球晶的生成条件和环带周期结构,因此可以通过改变端基的结构来调控PLLA所形成的环带结构.分子量相近而端基不同的PLLA,在相同温度下结晶时,刚性引发剂苯甲醇...     

分子氧对光合作用原初反应模拟体系中能量转移的影响

叶绿素吸收光能后,在光合作用能量传递的途径中,质醌被认为是原初光反应中叶绿素光能转换的原初受体。因此研究能量转移的模拟光合作用原初反应体系,用醌类化合物做光激发叶绿素的电子受体,为研究电子传递途径、方式和可能的机理,受到了相当的重视。在这类相当广泛的研究中,虽然提出了各说不一的机理,但其结果都得到了叶绿素阳离子((chl⁺)和半醒阴离子(Q^-)自由基,肯定了光激发的叶绿素能量首先传递给醒的结论。     

THE EFFECT OF ACCEPTOR GROUP VARIATION ON THE SOLVATOCHROMISM OF DONOR-ACCEPTOR FLUOROPHORES

Abstract The absorption and emission characteristics of five hydroxytetrahydrochrysenes substituted with acceptor groups (nitro, cyano, methylketone, 1° amide and methyl ester) (THC-NO₂, THC-CN, THC-COCH₃, THC-CONH₂ and THC-CO₂CH₃, respectively) were investigated in an extensive set of solvents. The order of absorption and fluorescence bathochromicity are: THC-NO₂ > THC-COCH₃ > THC-CN ≥ THC-CO₂CH₃ > THC-CONH₂ and THC-NO₂ >> THC-COCH₃ > THC-CO₂CH₃ > THC-CN > THC-CONH₂, respectively. The emission spectra of these compounds are sensitive to the solvent polarity (E_T[30] scale) in the order: THC-NO₂ > THC-COCH₃ > THC-CO₂CH₃ > THC-CONH₂ > THC-CN. The response of the emission maxima of these compounds to the solvent polarity and hydrogen-bond donor/acceptor properties (π*/α/β and acity/basity scales) was also determined. The emission energies of THC-NO₂ were most sensitive to π*, β, acity, and basity of the solvent; those of the amide were least sensitive to the solvent π*, β, and basity. The ground- and excited-state dipole moments were determined by semiempirical molecular orbital calculations and the absorption/fluorescence solvent-shift method, respectively. THC-NO₂ had the largest ground- and excitedstate moments. The ester and amide had the smallest ground- and excited-state moments, respectively. In general, unsatisfactory results were obtained for correlations of the emission and absorption energies, fluorescence solvatochromism and the ground- and excited-state dipole moments with the Hammett substituent constants of the five acceptor groups. Acceptable correlations were obtained for the absorption and emission energies and the fluorescence solvatochromism with the substituent constants if the cyano compound was excluded.     

THE EFFECT OF POLYMER COMPOSITION ON THE MOLECULAR ADSORPTION AREA OF THE EMULSIFIER

Conductometric coap titration and Maron's³ method of plotting polymer concentration vs. soap concentration is used to determine the molecular adsorption area (MAA) of potassium oleate in a number of polymer and copolymer latex systems. It is demonstrated that the MAA of potassium oleate increases in the series polystyrene→ polybutadiene→polystyrene-coacrylonitrile as well as in a series of polystyrene-coacrylonitrile systems with increasing acrylonitrile content in the polymer composition

It is further demonstrated that the MAA increases with temperature at rates dependent on the chemical nature of the polymer systems. The composition induced increases in the MAA correlate as well with the polar nature of the polymer and are attributed to decreasing solubility of the lyophilic segment of the emulsifier chain in the polymer. Temperature induced MAA increases are attributed to Increasing mobility of the hydrophylic emulsifier segment in the aqueous phase.     

相分离聚合法:(Ⅰ)羧酸型共聚功能微球的合成

Crosslinked functional microspheres with Carboxylic group have been synthesized by the method of Phaseseparated polymerization from monomers of methacrylic acid and other vinyl-type monomers. The effects of reaction condition such as comonomer, crosslinking agent, initiator and polymerization temperature, as well as polymerization time on the morphological structure of microspheres formed have been studied. The functional polymeric microspheres with good spherical form, diameter near 5 micrometers, narrow dispersion in diameter and contained carboxylic group can be synthesized stably.     

EFFECT OF AGGREGATION ON THE HEMATOPORPHYRIN-SENSITIZED PRODUCTION OF SINGLET MOLECULAR OXYGEN

Abstract— The hematoporphyrin-sensitized production of singlet molecular oxygen, O₂(¹Δ_g), has been investigated in methanol and in aqueous solution. The quantum yield for formation of O₂(¹Δ_g) (Φ_Δ) has been measured by both steady-state (oxygen consumption) and time-resolved (near-infrared luminescence) methods. In methanol, both techniques indicate that Φ_Δ= 0.76 and the value remains independent of sensitizer concentration over a wide range. This finding is consistent with the dye persisting in a monomelic form in methanol solution. In contrast, Φ_Δ decreases markedly with increasing sensitizer concentration in water due to dimerization of the dye. Analysis of the steady-state data indicates Φ_Δ values of 0.74 and 0.12, respectively, for monomer and dimer. It is further shown that the efficiency whereby quenching of the triplet state by O₂ results in generation of O₂(¹Δ_g) is substantially lower for the dimer than for the corresponding monomer. Because monomer and dimer possess quite different absorption spectral profiles, the efficacy for photodynamic action with hematoporphyrin exhibits a pronounced wavelength dependence.     

分子结构对1,2-聚丁二烯橡胶性能的影响

本文研究了分子链结构、分子量及其分布对钼催化聚合1,2-聚丁二烯(1,2-PB)的加工工艺性能及硫化胶性能的影响.实验发现,1,2-PB的加工工艺行为随分子量降低和分子量分布加宽而得以改善,其抗湿滑性能随分子链中1,2-结构含量增加而提高,而1,2-结构的空间规整性—间同含量的增加则导致1,2-PB应变诱导结晶、降低硫化胶的弹性和增加生热值。     

相分离聚合法:(Ⅰ)羧酸型共聚功能微球的合成

粒径在微米级、粒度分布窄的高分子微球具有十分广泛的应用。但是由于这样规格的微球正是在一般的悬浮聚合和乳液聚合的合成范围之外,而采用二步聚合法和种子聚合法则不是需要使用特殊的反应装置,就是合成步聚十分繁复,因此至今对于这样规格高分子微球的报道不多。     

关于电化学极化能否改变电极内部费米能级位置的讨论

Khan等人近年一再发表关于电化学极化不能影响电极内部费米能级以及改变电极和溶液两相内部费米能级相对位置的观点。在[3]中更详细地阐述了这种观点。按照作者的意见,根据 E_F=h~2/8π~2m_■~*(3π~2n_e)~2/3 (1)(式中m_■~*为电子的有效质量,n_e是自由电子的浓度,见[3]中第309页,但原文中n_e误写作分母),由于在良电子导体中电场不能进入整体相内部,其中的剩余电荷只可能分布在距     

THE EFFECT OF ACIDS ON THE INFRARED SPECTRA OF SCHIFF BASES—I. NON-CONJUGATED IMINES

The Fourier-transform infrared spectra of CHCl₃ solutions containing a non-conjugated imine, R₁HC=NR₂ and an acid of the series HCl, HBr, HI, trichloro-, dichloro-, monochloro-, monobromo acetic acids and propionic acid have been recorded. Both the N⁺H and double bond stretching regions are examined. The results show that HCl, HBr and HI protonate the imine completely, trichloroacetic acid to about 90-95%, the other haloacetic acids to 55-80% and propionic acid to <10%. Considered as model studies for the problem of protonation in rhodopsins our results lead to the conclusion that with the relatively weak acids available in the pigments full protonation requires a stabilization mechanism which should be further investigated.     

聚硅氧烷侧基极性对链均方偶极矩的影响

为了改进无机高分子链偶极矩的计算,在旋转异构态模型和生成矩阵统计方法基础上,导出了可以同时考虑骨架键和侧基极性的均方偶极矩公式,应用于对称和不对称聚硅氧烷高分子链的偶极矩构象构型统计性质的分析,及聚二甲基硅氧烷(PDMS)链、聚甲基苯基硅氧烷(PMPS)链是否考虑侧基极性的偶极矩比较。计算结果表明,PDMS的偶极矩特征比值0.36与实验结果一致,它大于忽略侧基极矩的特征比值约46%,均方偶极矩温度系数为1.29×10-3K-1,无规聚甲基苯基硅氧烷链(50%i-PMPS)的均方偶极矩特征比和温度系数分别为0.61和1.73×10-3K-1.不考虑侧基极性的均方偶极矩特征比与PDMS不考虑侧基时趋于同样的值0.20.对PMPS偶极矩与链规整性关系研究发现,PMPS间同链的均方偶极矩要大于全同和无规链,而全同链温度系数最大.均方偶极矩对一级相互作用能的依赖程度依次按间同链、无规和全同链顺序增加,而间同和全同链均方偶极矩受二级相互作用能的影响要大于无规链.     

THE EFFECT OF MOLECULAR SHAPE ON THE FLUORESCENT PROPERTIES OF 9, 10-DIPHENYLANTHRACENE

Abstract. ESR measurements on 9, 10-diphenylanthrace in solution show that the molecule is non-planar, the two phenyl rings being twisted by about 66° relative to the anthracene nucleus. This agrees with previous predictions made on the basis of scale models.
Evidence from absorption and fluorescence spectra for a change of angle between ground and excited state is examined, and a decrease of about 6° is found for the excited state. On the basis of the large angle of twist possible reasons are suggested for the difference between anthracene and 9, 10-diphenylanthracne with regard to dimer formation and quantum yield of fluorescence in solution.