Molecular structure of compounds containing a 2,2′-bithienyl fragment (review)

The results of X-ray crystallographic investigations of compounds containing a 2,2-bithienyl fragment are summarized and analyzed. The structural characteristics of unsubstituted bithiophene, 5-monosubstituted, 5,5-, 3,3-, 4,4-, and 3,4-disubstituted, and more highly substituted bithiophenes and also the structure of -conjugated oligothiophene derivatives are considered.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–760, June, 2000.     

Synthesis and crystal structure of a new molecular complex of fullerene C70, 4BNDY·3C70·4C6H6 (BNDY is binaphtho[1,8-d,e]-1,3-dithiin-2-ylidene)

A new C₇₀-based molecular complex 4BNDY·3C₇₀·4C₆H₆ (1) (BNDY is binaphtho[1,8-d.e]-1,3-dithiin-2-ylidene) was prepared, and its full X-ray diffraction study at room temperature was performed. The C₇₀ molecules in crystal 1 are ordered in different ways, and their ordering depends on van der Waals interactions between them and nonplanar BNDY molecules in the boat conformation. The neighboring BNDY molecules in the structure are bound to each other by π-π interactions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 99–102, January, 2000.     

新型不对称吡喃鎓方酸菁染料的晶体结构

通过缓慢挥发溶剂法得到一种不对称吡喃方酸菁染料的单晶,测定了其晶体结构.其晶系为三斜晶系,空间群为P1,a=0.9228(4),b=1.4122(6),c=0.6124(3)nm,α=93.97(4),β=98.14(5),γ=71.05(4),V=0.7470(6)nm³,Z=1.用晶体结构数据解释了此不对称染料的¹H-NMR谱.     

{[Ag(ATO)_2]CIO_4}_n的制备和分子结构

通过4-氨基-1,2,4-三唑-5-酮(ATO)水溶液与高氨酸银溶液反应,制备了聚高氨酸二(4-氨基-1,2,4-三唑-5-酮)合银(Ⅰ).并用X射线衍射、红外光谱和TG-DTG对其进行了结构表征.晶体属三斜晶系,空间群为P1,a=0.7534(1)nm,b=0.8505(1)nm,c=1.0257(1)nm;α=69.47(1)°,β=72.69(1)°,γ=86.00(1)°;V=0.5872(1)nm~3,Z=2,D_c=2.305g/cm~3,F(000)=400;偏离因子R为0.0358.中心银离子表现为较为特殊的三配位.     

Effect of Addition of MTES on the Structure of Siloxane-PPG Nanocomposites

Hybrid transparent and flexible siloxane-polypropyleneglycol (PPG) materials with covalent bonds between the inorganic (siloxane) and organic (polymeric) phases were prepared by sol-gel process. In order to improve the quality of the mechanical properties of these materials, different amounts of methyltriethoxysilane (MTES) were added to the initial sol. The effect of MTES addition on the structure of the composites was studied by Small-Angle X-Ray Scattering (SAXS) and ²⁹Si Nuclear Magnetic Resonance (²⁹Si NMR). In absence of MTES, SAXS spectra exhibit a peak that is assigned to spatial correlation due to short range order between the siloxane clusters embedded in the polymeric phase. The experimental results indicate that, for low MTES concentrations ([MTES]/[O] 0.8, O: ether-type oxygen of PPG), the silicon species resulting from hydrolysis and condensation of MTES fill the open spaces between polymeric chains, interacting with the ether-type oxygens. For larger MTES content ([MTES]/[O] 0.8), the number of free ether-type oxygen sites avalaible for reaction with such silicon species is not large enough. Consequently, a fraction of silicon species resulting from MTES addition graft to siloxane clusters formed by hydrolysis and condensation of the hybrid precursor. For all MTES concentrations the condensation degree of the siloxane phase, determined from ²⁹Si NMR spectroscopy, is high (>69%), as expected under neutral pH synthesis conditions.     

Photoinitiated processes in 1-p-tolylsulfonylazo-2,4,6,8-tetrakis(tert-butyl)phenoxazine

New photochromic compound 1-p-tolylsulfonylazo-2,4,6,8-tetrakis(tert-butyl)phenoxazine containing the intramolecular hydrogen bond NH...N and the corresponding model structures 2,4,6,8-tetrakis(tert-butyl)-1-(veratroylazo)phenoxazine and 2,4,6,8-tetrakis(tert-butyl)-N-acetyl-1-(p-tolylsulfonylazo)phenoxazine were synthesized and studied. The data obtained suggested the mechanism of the photoreaction resulting in the accumulation of betaine 1-hydroxy-2,4,6,8-tetrakis(tert-butyl)-10-tolylsulfonylphenoxazin-9-one. The photochromic transformations in the molecule under study are due to intramolecular proton phototransfer followed by E–Z-isomerization about the N–N bond and the formation of betaine 1-hydroxy-2,4,6,8-tetrakis(tert-butyl)-10-tolylsulfonylphenoxazin-9-one. The molecular and crystal structure of the photoproduct was studied by X-ray analysis.     

A genetic algorithm for the automated generation of small organic molecules: Drug design using an evolutionary algorithm

Rational drug design involves finding solutions to large combinatorial problems for which an exhaustive search is impractical. Genetic algorithms provide a novel tool for the investigation of such problems. These are a class of algorithms that mimic some of the major characteristics of Darwinian evolution. LEA has been designed in order to conceive novel small organic molecules which satisfy quantitative structure-activity relationship based rules (fitness). The fitness consists of a sum of constraints that are range properties. The algorithm takes an initial set of fragments and iteratively improves them by means of crossover and mutation operators that are related to those involved in Darwinian evolution. The basis of the algorithm, its implementation and parameterization, are described together with an application in de novo molecular design of new retinoids. The results may be promising for chemical synthesis and show that this tool may find extensive applications in de novo drug design projects.     

N,N-二(2-苯并咪唑亚甲基)甲胺高氯酸盐的晶体和电子结构

合成了三齿配体N,N-二(2-苯并咪唑亚甲基)甲胺(MN3)的高氯酸盐.对该化合物进行了元素分析、紫外和红外表征;采用X射线衍射方法测定了该化合物的晶体结构,依据晶体结构数据使用G98程序对配体(MN3)进行了量子化学计算.     

新型含氟α-氨基膦酸酯的合成和晶体结构

利用含氟苯基亚胺与亚磷酸酯反应,合成了新型含氟α-氨基膦酸酯,通过元素分析、红外光谱、质谱、核磁共振氢谱对其结构进行了表征.X射线单晶衍射测试结果表明:化合物为三斜晶系,空间群P1,a=1.0178(6)nm,b=1.0354(6)nm,c=2.2534(13)nm,α=77.413(10)°,β=78.340(10)°,y=77.540(10)°,V=2.233(2)nm3,Z=4,Dc=1.289 Mg·m-3,μ=O.175 mm-1,F(000)=904.0,最终偏离因子R=0.0728,wR=0.1724.