流动-差热吸附量热系统 Ⅰ. 装置考察与氢型丝光沸石(HM)-苯体系吸附热的测定

本文介绍了一种差热分析(DTA)与色谱联用的吸附量热系统。经特别设计的柱恒温箱把差热与色谱结合起来, 达到了吸附量热所要求的高灵敏度与低噪声。配置了可变宽度的矩形脉冲进样系统。进样与响应的同步性良好。结合 HM-苯体系吸附热的测定, 给出了量热图谱的解析方法。得出了与文献中吸附微量热计接近的结果。利用本系统还可获得吸附平衡的信息。结果表明, 量热与吸附平衡实验数据之间具有良好的一致性。本系统适用于在接近工业反应的动态条件下研究催化剂的吸附性能。     

Synthesis,crystal structure and ferro-magnetic interaction of a binuclear copper(II) complex with the 1,4-dinitro-2,3,5,6-tetracarboxylatobenzenic anion as bridging ligand

A binuclear complex [Cu₂(DTB)(DMF)₄(H₂O)]·2DMF (DTB = 1,4-dinitro-2,3,5,6-tetracarboxylatobenzenic anion; DMF = N,N-dimethylformamide) has been synthesized and its crystal structure determined by X-ray crystallography. In the complex Cu ion is located in a distorted square pyramidal environment with two oxygen atoms O(1) and O(3) from two carboxylate groups, another two oxygen atoms O(7) and O(8) from terminal ligands of two DMF molecules, and a fifth coordinated oxygen atom O(9) from the terminal ligand of one H₂O molecule, in which the O(8) atom is situated in the apex of the pyramid. DTB as bridging ligand coordinates two Cu ions through its four carboxylate groups. The variable-temperature magnetic susceptibility of the complex was measured in the 5–300 K range. The magnetic coupling parameter is consistent with a ferromagnetic exchange between the two copper(II) centers and the data fit a binuclear magnetic exchange model based on the Hamiltonian operator ( = -2J₁₂, ₁ = ₂= 1/2), giving the ferromagnetic coupling parameter of 2J = 1.80 cm^{- 1}. This is the first example of a tetracarboxylatobenzenic bridging complex exhibiting ferromagnetic interaction.     

Spectroscopic evidence for triplet excitation energy transfer among carotenoids in the LH2 complex from photosynthetic bacterium <Emphasis Type="Italic">Rhodopseudomonas palustris</Emphasis>

The LH2 complex from Rhodopsudomonas (Rps.) palustris is unique in the heterogeneous carotenoid compositions. The dynamics of triplet excited state Carotenoids (³Car* has been investigated by means of sub-microsecond time-resolved absorption spectroscopy both at physiological temperature (295 K) and at cryogenic temperature (77K). Broad and asymmetric T _n ←T ₁ transient absorption was observed at room temperature following the photo-excitation of Car at 532 nm, which suggests the contribution from various carotenoid compositions having different numbers of conjugated C=C double bonds (N_c=c). The triplet absorption bands of different carotenoids, which superimposed at room temperature, could be clearly distinguished upon decreasing the temperature down to 77 K. At room temperature the shorter-wavelength side of the main T_n04T₁ absorption band decayed rapidly to reach a spectral equilibration with a characteristic time constant of ∽1 μs, the same spectral dynamics, however, was not observed at 77 K. The aforementioned spectral dynamics can be explained in terms of the triplet-excitation transfer among heterogeneous carotenoid compositions. Global spectral analysis was applied to the time-resolved spectra at room temperature, which revealed two spectral components peaked at 545 and 565 nm, and assignable to the T_n04 T₁ absorption of Cars with Nc=c=11 and Nc=c=13, respectively. Surprisingly, the decay time constant of a shorter-conjugated Car, i.e. 0.72 ώs (aerobic) and 1.36 ώs (anaerobic), is smaller than that of a longer-conjugated Car, i.e. 2.12 us (aerobic) and 3.75 ώs (anaerobic), which is contradictory to the general rule of carotenoids and relative polyenes. The results are explained in terms of triplet-excitation transfer among different types of Cars. It is postulated that two Cars with different conjugation lengths coexist in an α, β-subunit in the LH2 complex.     

NBR/ORGANOMODIFIED BENTONITE INTERCALATED HYBRIDS AND THEIR EFFECTS ON THE TOUGHNESS OF PVC

Hybrids of intercalative nitrile-butadiene rubber/organomodified bentonite (NBR/OMB) were prepared by thelatex intercalation technique. Investigation of their mechanical properties and the microstructore of NBR/OMB showed thatthe organomodified bentonite is an effective toughener for NBR. Transmission electronic microscopy (TEM) and X-rnydiffraction (XRD) tests showed that the NBR macromolecule could be intercalated into the galleries of bentonite.Incorporation of NBR/OMB hybrids as tougheners into poly(vinyl chloride) (PVC) results in a substantial increase in theimpact strength of PVC, but little decrease in its tensile strength and flexural strength, compared to the unmodified PVC.     

Synthesis,characterization and interaction of mixed polypyridyl ruthenium(II) complexes with calf thymus DNA

New mixed polypyridyl {HPIP = 2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline, phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline, dmb = 4,4-dimethyl-2,2-bipyridine} ruthenium(II) complexes [Ru(phen)₂(HPIP)]²⁺, [Ru(dmp)₂(HPIP)]²⁺ and [Ru(dmb)₂(HPIP)]²⁺ were synthesized and characterized by elemental analyses ¹H-n.m.r., u.v.–vis. spectroscopy and cyclic voltammetry. Their DNA-binding properties were demonstrated by absorption, luminescence titrations, steady-state emission quenching and viscosity measurements. The results suggested that all the examined complexes bind with CT-DNA intercalatively. Methyl groups substituted at the 4,4-positions of bpy has no obvious effect on its DNA binding, whereas substituents at the 2- and 9-positions of phen have an impressive effect on its DNA-binding, as revealed by the decreased binding affinity.     

铅在铂电极上的还原电位溶出分析法

研究了以亚铁氰化钾为还原剂铅在铂电极上的还原电位溶出法；讨论了电极的预处理、阳极富集和随后的还原电位溶出及铅测定的干扰。     

乙基橙与α,β,γ-环糊精包结物诱导圆二色性的研究

本文研究了乙基橙(EO)α、β、γ、环糊精(CD~x)包结物的诱导圆二色性(ICD)。用Kirkwood偶合振动模型探讨了包结物的包结形式都为轴向包结。然后利用Job连续变量作图法确定了其络合比, 即a-CDx/EO=1:1,βCDx(γ-CDx)/EO=2:1、1:1。     

STUDY ON THE CONCENTRATION DEPENDENCE OF ORIENTATION OF POLYSTYRENE ON SILVER BY THE SERS TECHNIQUE*

Polystyrene films were adsorbed onto a silver surface from dichloromethane solutions with concentrations of 0.1 to12 wt%, and then studied by the surface enhanced Raman technique. A critical concentration for coil interpenetration wasobserved.     

裂解色谱法研究PMR型聚酰亚胺前体的反应过程

用裂解气相色谱法研究ＰＭＲ型聚酰亚胺前体在反应中的化学变化过程，以裂解产物醇和环戊二烯的生成率表示酰胺化或酰亚胺化及交联的程度，结果表明，酰胺化或酰亚胺化在５０℃以下不发生，在１８０～２２０℃完成，降冰片烯端基在１５０℃以下不发生交联反应，在２８０℃，１０～１８小时可完成交联反应。     

二(邻香草醛缩丙醇胺)异硫氰酸根合锰(Ⅲ)的合成与晶体结构

本文报道了一个新配合物—二(邻香草醛缩丙醇胺根)异硫氰酸根合锰(Ⅲ)的合成及其晶体结构。配合物属于单斜晶系，空间群为P2₁/c，晶胞参数为：a=8.565(1), b=21.814(2), c=12.787(2)?, β=92.80(1)°。锰为六配位，在两个邻香草醛缩丙醇胺Schiff碱配体中，一个为三齿配体，另一个为双齿配体。NCS^-离子以N在轴向上与锰发生配位，由于Jahn-Teller效应，其键长为2.193?。另外晶胞中存在着罕见的H……S-C≡N氢键。