Publications (20) View all
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Article: Towards molecular design rationalization in branched multi-thiophene semiconductors: the 2-thienyl-persubstituted alpha-oligothiophenes.
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ABSTRACT: The introduction of branching in multi-thiophene semiconductors, although granting the required solubility for processing, results in an increased molecular fluxionality and a higher level of distortion, thus hampering pi conjugation. Accordingly, branched oligothiophenes require rationalization of their structure-reactivity relationships for target-oriented design and optimization of the synthetic effort. Our current research on spiderlike oligothiophenes affords deep insight into the subject, and introduces new, easily accessible molecules with attractive functional properties. In particular, a regular series, T'X(Y), of five new multi-thiophene systems, T'5(3), T'8(4), T'11(5), T'14(6), and T'17(7), constituted by five, eight, 11, 14, and 17 thiophene units, respectively, their longest alpha-conjugated chain consisting of tri-, tetra-, penta-, hexa-, and heptathiophene moieties, respectively, has been synthesized and fully characterized from the structural, spectroscopic, and electrochemical point of view. The electronic properties of the monomers and their electropolymerization ability are discussed and rationalized as a function of their molecular structure, particularly in comparison with the series of 5-(2,2'-dithiophene)yl-persubstituted alpha-oligothiophenes (TX(Y)) previously reported by us. These oligothiophenes are easily accessible materials, with promising properties for applications as active layers in multifunctional organic devices including solar cells.Chemistry 08/2010; 16(30):9086-98. · 5.93 Impact Factor -
Article: Free design of chiral diphosphine chelating ligands for stereoselective homogeneous catalysis by assmbling five‐membered atomatic heterocycles
Journal of Heterocyclic Chemistry 03/2009; 39(3):471 - 485. · 1.22 Impact Factor -
Article: Process-scale preparation of enantiomerically pure gamma-lactones by asymmetric hydrogenation of gamma-ketoesters and comparative tests of the sensory properties of some antipodes
Tetrahedron Asymmetry 01/2004; 15(14):2289-2297. · 2.65 Impact Factor -
Article: A new modular class of easily accessible, inexpensive, and efficient chiral diphosphine ligands for homogeneous stereoselective catalysis.
The Journal of Organic Chemistry 09/2001; 66(17):5940-2. · 4.45 Impact Factor -
Article: Steric and Electronic Effects on the Configurational Stability of Residual Chiral Phosphorus-Centered Three-Bladed Propellers: Tris-aryl Phosphanes.
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ABSTRACT: A series of tris-aryl phosphanes, structurally designed to exist as residual enantiomers or diastereoisomers, bearing substituents differing in size and electronic properties on the aryl rings, were synthesized and characterized. Their electronic properties were evaluated on the basis of their electrochemical oxidation potential determined by voltammetry. The configurational stability of residual phosphanes, evaluated by dynamic HPLC on a chiral stationary phase or/and by dynamic (1) H and (31) P NMR spectroscopy, was found to be rather modest (barriers of about 18-20 kcal mol(-1) ), much lower than that shown by the corresponding phosphane oxides (barriers of about 25-29 kcal mol(-1) ). For the first time, the residual antipodes of a tris-aryl phosphane were isolated in enantiopure state and the absolute configuration assigned to them by single-crystal anomalous X-ray diffraction analysis. In this case, the racemization barrier could be calculated also by CD signal decay kinetics. A detailed computational investigation was carried out to clarify the helix reversal mechanism. Calculations indicated that the low configurational stability of tris-aryl phosphanes can be attributed to an unexpectedly easy phosphorus pyramidal inversion which, depending upon the substituents present on the blades, can occur even on the most stable of the four conformers constituting a single residual stereoisomer.Chemistry 02/2013; 19(1):182 – 194. · 5.93 Impact Factor
