Copolymerization of 1-Vinyl-1,2,4-triazole with 2-Hydroxyethyl Methacrylate

Radical copolymerization of 1-vinyl-1,2,4-triazole with 2-hydroxyethyl methacrylate in dimethylformamide and ethanol, initiated with azobis(isobutyronitrile), was studied. The copolymerization constants of this pair of monomers at low conversions and the microstructure parameters were determined. New highly hydrophilic thinly cross-linked copolymers were prepared from these monomers in the presence of crosslinking agents.     

Studies of carbazole-based polyarylates

A low temperature solution condensation method with pyridine as acceptor-catalytic reagent was applied to the synthesis of polyarylates from carbazole and bisphenol A/phenolphthalein. The polyarylates were classified with respect to their structure, thermal stability, and dielectric behavior.     

Synthesis and spatial structure of the geometrical isomers of 4-substituted 1-tert-butyl-3-methyl-piperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines

In order to study the interrelationship between the structure, reactivity, and spectroscopic characteristics of the stereoisomeric piperidines, starting from 1-tert-butyl-3-methylpiperidin-4-one the synthesis has been performed of the geometric isomers of some 4-substituted 1-tert-butyl-3-methylpiperidin-4-ols and 4-acyloxy-1-tert-butyl-3-methylpiperidines. The spatial structures of the compounds obtained have been determined by IR and PMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1056–1061, August, 1973.     

Die Molekül- und Kristallstruktur von Di-μ-sulfato-μ-hydroxo- bis[triamminkobalt(III)]sulfat-8-Hydrat

The crystal structure of Di-μ-sulfato-μ-hydroxo-bis[triamminecobalt(III)] sulfate 8-hydrate has been determined from three-dimensional x-ray data collected by counter techniques. The structure was refined using 2515 independent reflections and the refinement converged to a conventional R factor (on F) of 3.8%. The compound crystallizes in the monoclinic space group C—P2/a, a = 14.122(9), b = 9.858(2), c = 18.81(2) Å, β = 139.3(4), Z = 2, d_obsd = 2.086 g/cm³ and d_calc = 2.14 g/cm³. Within the cation two bidentate SO₄-ligands form bridges between two cobalt atoms. There are two types of S? O bonds (1.50 Å endocyclic, 1.45 Å exocyclic).     

The microwave spectrum and dipole moment of 1,1-diflurobenzocyclopropene

The rotational spectrum of 1,1-difluorobenzocyclopropene, measured in the X- and R-bands, has been analysed to give the rotational constants in the ground and first four vibrational states. These constants are in agreement with a structure based on those of crystallographically determined related molecules. Indirect evidence is adduced that the carbon skeleton is indeed planar. The dipole moment in the ground (3.57₂ ± 0.02 D) and first excited state (3.54 ± 0.03 D) has been determined through an analysis of the second-order Stark effect. This high value implies considerable polarisation of the π-electron framework.     

Conformations of fused cycloalkanes in organometallic complexes : IV. The crystal and molecular structure of tricyclo-[6.4.0.02.7]dodeca-3,5-dienetricarbonyliron

The precise molecular structure of the title compound has been determined by single crystal X-ray diffractometry. It consists of a cyclohexadiene ring fused at the 5 and 6 positions to a cyclobutane ring which is in turn fused to a cyclohexane ring. The two six-membered rings are trans to each other with respect to the shared four-membered ring. The Fe(CO)₃ moiety is bound in the usual way to the conjugated diene portion of the cyclohexadiene ring. The feature of greatest interest is the mutual influence of the conformations of the two fused cycloalkane rings, whose intrinsically preferred conformations are mutually incompatible. Under the influence of the fused cyclohexadiene ring the C₄ ring would tend to be planar, while the cyclohexane ring would tend, of itself, to have a chair conformation. The actual result is a compromise, with the C₄ ring being folded by 15° along its diagonal and the C₆ ring having a conformation intermediate between planarity and a chair. Crystallographic data: space group, P2₁, Z = 2. Unit cell dimensions at 3°C are a = 6.176(1), b = 11.307(2), c = 9.781(2) Å and β = 92.89(2)°. A set of 1733 reflections having 2θ(Mo-K_α) < 63.7° and I > σ(I) was refined to convergence (R₁ = 0.055; R₂ = 0.034) with hydrogen atoms refined isotropically and all others anisotropically.     

Determination of boron in nickel-base alloys by the dianthrimide method

The dianthrimide method for the determination of boron in iron and low-alloy steels may be applied to nickel-base materials. The sample is dissolved, without any loss of boron, by hydrochloric and sulphuric acids and the resulting boric acid determined spectrophotometrically with dianthrimide. Background corrections are necessary to compensate for the absorbance from ions such as nickel and iron.     

Fluorous synthesis of minor groove binding agents related to distamycin

Minor groove binding agents related to distamycin have been shown to target specific DNA sequences with high affinity. We report a new method for the preparation of these agents using fluorous synthesis in which the fluorous tag is located on what will become the cationic tail of the molecule. We demonstrate that fluorous synthesis yields both simple and complex polyamides in good yields and in high purity.