On quantum-chemical estimates of constants of isotropic hyperfine coupling with protons in free radicals

A scheme of consitent quantum-chemical calculations of constants of isotropic hyperfine coupling (IHFC) with protons (a _H ^iso ) in free radicals is considered for the case where the spin populations ρ_s ^H are determined in the basic set of symmetrically orthogonalized atomic orbitals taking model σ-and π-electron fragments as an example. The competence of using two coefficients of proportionalityK(H) when estimating the proton IHFC constants by semiempirical quantum-chemical methods was demonstrated. Theoretical substantiation of empirical values of the above coefficients previously used is revealed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 245–249, February, 1999.     

Evaluation of a new procedure for quantum-chemical estimates of constants of isotropic hyperfine coupling with protons in free radicals

A new procedure for quantum-chemical estimates of the constants of isotropic hyperfine coupling (IHFC) with protons using the orbital spin populations calculated in the basis set of symmetrically orthogonalized (according to Löwdin) atomic orbitals is tested taking 16 well-studied simplest π-electron and σ-electron radicals as examples. The most probable reasons for and possible ways of correcting large deviations of calculated IHFC constants from experimental values are considered. The efficiency of the semiempirical MNDORU scheme, which makes it possible to consistently estimate the delocalization and spin-polarization contributions to the constants of IHFC with protons in free radicals, is demonstrated.     

甲酰胺溶剂中溶质间的过量Gibbs自由能相互作用参数

利用气液色谱方法测定了２９８．１５Ｋ时若干非电解质溶质在甲酰胺－乙酰胺、甲酰胺－尿素、甲酰胺－高氯酸钠固定液中的保留参数，采用ＭｃＭｉｌａａｎ－Ｍａｙｅｒ理论，将溶液热力学过量性质与溶液中粒子的对相互作用，参相互作用参数相联系，利用热力学方法求得了溶质的保留参数与Ｇｉｂｌｓ自由能相互作用参数的关系，并就溶质－溶质间的相互作用及溶剂性质的影响进行了讨论。     

具有生物活性的有机硅化合物研究(Ⅺ)——2-(三甲硅基)乙基硫代(N-取代)乙酰胺的研究

研究了2-(三甲硅基)乙基硫代乙酸与(取代)苯胺和脂肪胺直接缩合反应或在五氧化二磷存在下的反应,发现前者收率高于后者。由此合成了17种结构新颖的2-(三甲硅基)乙基硫代(N-取代)乙酰胺类化合物。通过NMR(¹H,¹³C)、IR和MS的研究,确定了这类化合物的结构,并探讨了化合物结构与波谱的关系。经测定,这些化合物的生物活性不甚理想。     

Synthesis and X-ray crystallographic structures of [HGa(NMe2)2]2 and [PhGa(NHNMe2)2]2, and room-temperature conversions of [HGa(NMe2)2]2 to (HGaNH)n and (HGaNMe)n

The reactivity of bis(dimethylamido) complexes of phenyl- and hydridogallium with ammonia, dimethylamine and 1,1-dimethylhydrazine is described. Synthesis of the starting gallium hydride, [HGa(NMe₂)₂]₂, was achieved in nearly quantitative yield from the reaction of HGaCl₂(quinuclidine) with LiNMe₂. In neat ammonia or methylamine at room temperature both dimethylamido ligands in [HGa(NMe₂)₂]₂ were substituted by a single equivalent of NH₃ or MeNH₂ to produce amorphous (HGaNH)_n or (HGaNMe)_n, respectively. In contrast, the reaction of [PhGa(NMe₂)₂]₂ with neat Me₂NNH₂, at room temperature consumed two equivalents of the substituted hydrazine to form [PhGa(NHNMe₂)₂]₂ in a 73% yield. Single crystal X-ray crystallographic analyses of [HGa(NMe₂)₂]₂ and [PhGa(NHNMe₂)₂]₂ establish that in the solid state both compounds adopt a cyclic Ga-N-Ga-N structure with a crystallographic center of symmetry located at the center of the ring.     

Determination of proteins by flow injection analysis coupled with the Rayleigh light scattering technique

A novel flow injection analysis (FIA) method with Rayleigh light scattering (RLS) detection was developed for the determination of protein concentrations. This method is based on the weak intensity of RLS of p-nitrohenzene-azo-3,6 disulfo-1-amino-8-naphthol-7-azo-benzene disodium salt (Amide Black-10B) which can be enhanced by addition of protein in weakly acidic solution. It has proved that the application of this method to quantify the proteins by using human serum albumin was available in real samples. In addition, this method is very sensitive (the determination limits are 0.11 μg/mL for human serum albumen (HSA) and 0.85 μg/mL for bovine serum albumen, BSA), simple, rapid and tolerance of most interfering substances. The FIA-RLS method was more stabile than the general RLS method and the average R.S.D. value of FIA-RLS less than general RLS. The effects of different interfering substances will be also examined. The amount of proteins in human serum sample was determined and the maximum relative error was no more than 3.00% as well as the recovery was between 94.9 and 105.9%.