106 research outputs found
Synthesis, variable temperature NMR investigations and solid state characterisation of novel octafluorofluorene compounds
The preparation of a number of new 9-substituted octafluorofluorene derivatives, solution NMR studies, and the first examples of solid state structures of octafluorofluorenes [1,2,3,4,5,6,7,8-octafluorofluorene, C13H2F8, 1; 1,2,3,4,5,6,7,8-octafluoro-9-(pentafluoro)phenylfluorene, C19HF13, 8; 1,1′,2,2′,3,3′,4,4′,5,5′,6,6′,7,7′,8,8′-hexadecafluoro-9,9′-bifluorenyl, C26H2F16, 11] are reported. Variable temperature 19F NMR investigations have been performed on the 9-aryl substituted compounds 1,2,3,4,5,6,7,8-octafluoro-9-(pentafluoro)phenyl-9-hydroxyfluorene, C19HF13O, 4, 1,2,3,4,5,6,7,8-octafluoro-9-(nonafluoro-4′-biphenylyl)-9-hydroxyfluorene, C25HF17O, 5, and 8, and the energetic barriers to rotation of the aryl have been determined. A lower rotational barrier is observed for compound 4 with respect to compound 8, while 5 does not show fluxional behaviour below 338 K. The results of the variable temperature experiments performed on 8 have been rationalized by 2D NMR studies, and compared to the solid state data resulting from the X-ray structural analysis
Silica-supported Ti chloride tetrahydrofuranates, precursors of Ziegler–Natta catalysts
Synthesis, structure and 1,3-butadiene polymerization behavior of vanadium(III) phosphine complexes
A series of vanadium(III) complexes bearing monodentate tertiary phosphine ligands of the type VCl3(PRnPh3-n)2 (n = 0 (1a); n = 1 and R = Me (1b), Et (1c), iPr (1d), Cy (1e); n = 2 and R = Me (1f), Et (1g), Cy (1h)), and VCl3(PR3)2 (R = Cyp (2a), Cy (2b),nPr (2c),tBu (2d)) were synthesized and characterized. In the case of 1c, 1g and 2a single crystals were also obtained and their molecular structures were determined. All the complexes were used, in combination with methylaluminoxane (sMAO) or AlMe3\u2013free MAO (dMAO), for the polymerization of 1,3-butadiene, exhibiting rather good activity and giving polymers with different microstructure depending on the nature of the phosphine ligand and the type of co-catalyst employed
Terpolymerisation of 1-olefin and ethene with CO catalysed by the [PdCl2(dppp)] complex in methanol as a solvent [dppp = 1,3-bis(diphenylphosphino)propane]
The catalytic activity of the [PdCl2(dppp)] complex in the 1-olefin/ethene (E)/CO terpolymerisation has been studied in MeOH (containing 1000 ppm of H2O) as a solvent. The 1-olefins tested were propene (P), 1-hexene (Hex), 1-decene (D) and styrene (S). At 90 °C and 45 atm (E/CO = 1/1), the system [PdCl2(dppp)]/TsOH (p-toluenesulfonic acid) = 1/8 catalyses efficiently the reactions leading to 5000 g PECO/(g Pd h), 5600 g HexECO/(g Pd h), 5650 g DECO/(g Pd h) and 4100 g SECO/(g Pd h). In particular, it has been studied deeper the effect of Hex and S concentrations on productivities, average molecular weights and melting temperatures of HexECO and SECO, respectively. A mechanism of reaction has been also proposed and discussed, supported by IR, and NMR characterizations
[Pd(chel)2][PF6]2 (chel = 2,2'-bipyrdil, 1,10-phenanthroline): efficient catalysts for the carbon monoxide - olefins copolymerization
Pd(chel)2(PF6)2 (chel = 2,2' bipyridyl, 1,10 phenanthroline): efficient catalysts for the carbon monoxide-olefins copolymerization
Procedimento per la preparazione di copolimeri a base di ossido di carbonio ed almeno un composto avente un'insaturazione alchenilica
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