Solvent-free synthesis of tris(4-hydroxybutyl acrylate) phosphate in the presence of 1-methylimidazole

In this paper, we present the synthesis of tris(4-hydroxybutyl acrylate) phosphate using 1-methylimidazole as acid scavenger for hydrochloric acid by-product, when an ionic liquid is formed. The synthesis was performed in the absence of any organic solvent. The yield is 83% for ester. The phosphate was characterized by ¹H–³¹P NMR and FTIR. The obtained phosphate is appropriate monomer for UV curing in the presence of photoinitiator. The obtained polymer was characterized by thermal analysis and LOI. The results showed good thermal stability and flame retardancy of UV-cured polymer.     

Synthesis and inclusion capability of a β-cyclodextrin-tetrathiafulvalene derivative

The synthesis of 4,5-ethylenedithio-4′-[6-deoxy-β-cyclodextrin-6-yl-aminocarbonyl]-tetrathiafulvalene 3 is reported. Dominantly, the structure of 3 has been established on the basis of mass spectrometry, ROESY and ¹H NMR spectra, combined with a theoretical MM3 study, indicating an ‘open-cavity structure’. The sensing ability of 3 and the formation constant of the complex [(3)-(1-adamantanol)] have been evaluated experimentally by UV-vis spectroscopy and theoretically by the MM3 docking procedure method.     

Projectively related complex Finsler metrics

In this paper we introduce in study the projectively related complex Finsler metrics. We prove the complex versions of the Rapcsák’s theorem and characterize the weakly Kähler and generalized Berwald projectively related complex Finsler metrics. The complex version of Hilbert’s Fourth Problem is also pointed out. As an application, the projectiveness of a complex Randers metric is described.     

The Adjoints of Dilation Operators on H-Cones

If S is an H-cone and P:SS is a localizable dilation operator on S (i.e., P is additive increasing, contractive, continuous in order from below and s(Ps+t–Pt+Pf)S, s,tS,f(S–S)₊), then it is proved that its adjoint P ^*:S ^*S ^* (i.e., P ^*=P) is also a localizable dilation operator. This is an improvement of a result obtained by G. Mokobodzki in the frame of excessive functions.     

Cytochrome P450 Catalyzed Oxidative Hydroxylation of Achiral Organic Compounds with Simultaneous Creation of Two Chirality Centers in a Single C?H Activation Step

Regio‐ and stereoselective oxidative hydroxylation of achiral or chiral organic compounds mediated by synthetic reagents, catalysts, or enzymes generally leads to the formation of one new chiral center that appears in the respective enantiomeric or diastereomeric alcohols. By contrast, when subjecting appropriate achiral compounds to this type of C H activation, the simultaneous creation of two chiral centers with a defined relative and absolute configuration may result, provided that control of the regio‐, diastereo‐, and enantioselectivity is ensured. The present study demonstrates that such control is possible by using wild type or mutant forms of the monooxygenase cytochrome P450 BM3 as catalysts in the oxidative hydroxylation of methylcyclohexane and seven other monosubstituted cyclohexane derivatives.     

Optimization of the response times of the feed kinematical linkages of the numerical control machine tools in order to minimize the path error

The main topic refers to enhancing the machining accuracy by minimizing the path error while machining through linear, circular or other interpolations on CNC machines for milling, boring and milling, grinding or turning. Currently the path error minimizing process while machining on CNC machine tools is a little explored, because of the absence of the dependence relations between the path error and the parameters of the kinematical axes taking part to the interpolation of the work piece contour. This work establishes and analyzes the relations of dependence between the path error and the response times of the kinematical axes that take part to the linear and circular interpolation. The theoretical results are experimentally verified by performing several machining operations through circular interpolation, where the moving speed along the contour and the response times of the kinematical axes are modified. The results of this research are intended for the machine tool designers and those who use such machines.     

M?ssbauer, TEM/SAED and XRD investigation on waste dumps of the Valea lui Stan gold mines

The complementary investigation techniques, M?ssbauer spectroscopy, transmission electron microscopy with selected area electron diffraction (TEM/SAED), X-ray diffraction (XRD) have been used to investigate the fate of the Valea lui Stan, Romania, gold-ore nanoscale-minerals during the long time of residence in the waste dumps. The preliminary investigations showed such waste dumps to contain significant amount of metals which cannot be identified by conventional methods. An intense research activity started up in order to evaluate the possibilities to recycle Valea lui Stan waste dumps and to recover metals by chemical or phytoextraction procedures. The waste dumps naturally show different mineral constituents with clay minerals as major phases, observed by XRD-technique. Although the waste dumps materials have whitish-yellowish colours, M?SSBAUER technique evidences the presence of the finely dispersed iron bearing minerals. The authors are focusing to inspect and analyze Fe-compounds in the samples collected from Valea lui Stan’s waste dumps in order to identify the magnetic phases by M?ssbauer technique.     

Inclusion ability of a monothiourea-tethered bis(β-cyclodextrin)

The tail-to-tail monothioureido β-cyclodextrin dimer has been prepared by reacting 6-amino-6-deoxy-β-cyclodextrin with 6-isothiocyanato-6-deoxy-β-cyclodextrin. The inclusion ability of this dimer has been evaluated by UV–visible spectroscopy for substrates of moderate molecular volumes (a wide variety of hydroxylated substrates) and was compared with genuine β-cyclodextrin and randomly methylated β-cyclodextrin. The definition of a complexation index allowed the treatment of these three host molecules on a hierarchical basis: the bis-cyclodextrin appears to be more efficient (average index = 1.17) than the methylated (1.07) or genuine (1.00) monomers. Thus, it seems that the cooperative phenomenon may lead to a general increase of the complexation ability, and not only to an enhanced recognition of specific guests. Surprisingly, this phenomenon is even really effective for the smallest substrates of our study. Such results prompted us to illustrate, on a steric point of view, the possibility of the face-to-face conformation by means of molecular modelling.