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The role played by the electronic properties and the steric features of bis(oxazoline) ligands in the Cu(I)-catalyzed cyclopropanation of styrene effected with ethyl diazoacetate was investigated. Two pairs of new bis(oxazolines) displaying flexible and atropisomeric 3,3'-bithiophene backbones were synthesized and structurally and electronically characterized.

Synthesis of 3,3-bis(diphenylphospino)-1,1'-dimethyl-2,2`biindole (N-Me-2-BINP) and 3,3-bis(diphenylphospino)-1,1'-bis(methoxymethyl)-2,2`-biindole (N-Me-2-BINP) is investigated. Reactions were found to be fast and enantioselection quite good.

Research demonstrates the synthesis of the chelating ligand enantiopure (plus)- and (minus)- 2,2',5,5'-tetramethyl-4,4'-bis(diphenylphosphino)-3,3'-bithiophene exhibiting a C(sub)2-symmetry. The electron rich metal associated diphosphine serves as catalysts in homogeneous hydrogenation of prostereogenic carbonyl functions.

The optically pure bis(diphenylphosphino)bibenzo[b]thiophenes tetraMe-bitianp and 4,5-demethylbenzo[b]thiophene belong to a new class of chiral ligands. The diphosphines can be utilized for asymmetric homogeneous catalysis with high enantioselectivity that is similar to binap ligands. The chiral ligands are composed of metallacycle with two interconnected five-membered units that exhibit good catalytic ability. The electronic properties of the phosphine groups and the configurational stability of the ligand depends on the type of heterocyclic system.

Research has been conducted on the chiral ligands capable of high enantioselectivity in homogeneous catalysis. The synthesis of the enantiopure diphosphine, a representative of this class of ligands, has been carried out and the application of the ruthenium, rhodium and palladium complexes as homogeneous catalysts is described.

The synthesis, structural characterization and some preliminary applications of (R,R)-2,5-dimethyl-[3,4-bis(2',5'-dimethylphospholanyl)]-thiophene are reported. This diphosphine is the first member of a new family of C(sub 2) symmetric hetero-DuPHOS ligands, characterized by the presence of two hormomorphic chiral 2,5-dimethyl-substituted phospholane groups bound to the homotopic ortho positions of a five-membered aromatic heterocycle.

The 2,5-dimethyl-3,4-bis [(2R,5R)-2,5-dimethylphospholano]thiophene (UlluPHOS), a new thiophene-based analogue of (R,R)-1,2-bis(phospholano)benzene (Me-DuPHOS), was synthesized, geometrically and electronically characterized, and employed as ligand of Rh and Ru in some standard hydrogenation reactions of prostereogenic functionalized carbon-carbon and carbon-oxygen double bonds. The synthesis of UlluPHOS is much easier than that provided for Me-DuPHOS. UlluPHOS and Me-DuPHOS display very similar geometries, while the electronic availability of the former is higher than that exhibited by the latter. The Rh and Ru complexes of UlluPHOS produced excellent enantiomeric excesses (98.9-99.5%) in the hydrogenation of N-acetyl-α-enamino acids and reaction rates higher than those found when employing the analogous complexes of Me-DuPHOS. [ABSTRACT FROM AUTHOR]

Provides evidence of the role played by the electronic properties of phosphorus in determining hydrogenation rate of the ketonic function of ethyl acetoacetate. Free energy linear correlation between the electrochemical oxidative potential of ligands exhibiting different electronic availability of phosphorus and the log of observed rate constant.

Straightforward enantioselective analytical methods are very important for drug safety, considering that in certain cases one of the two enantiomers of a chiral molecule might be harmful for humans. In this work, we propose a simple system for the direct and easy read-out of the enantiomeric excess of 3,4-dihydroxyphenylalanine (DOPA) as a model analyte. A conducting oligomer, i.e. oligo-(3,3'-dibenzothiophene), bearing inherently chiral features, is electrogenerated on a polypyrrole film. The resulting freestanding hybrid material is used as a wireless enantioselective actuator in a bipolar electrochemical cell. Combining in a single setup two individual actuators with opposite chiral features allows a direct visual read-out of enantiomeric excess, as the bending amplitude of each of the two actuators is directly correlated with the concentration of the corresponding stereoisomer of the analyte. Optimization of the experimental parameters results in efficient bending, giving access to the percentage values of the enantiomeric excess in mixtures containing different ratios of the antipodes, thus opening the way to potential applications for chiral in situ analysis., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

The novel [Re2(μ-H)(μ-OOC-CPDT)(CO)6(μ-3-Me-pydz)] complex (1; OOC-CPDT = 4H-cyclopenta[2,1-b:3,4-b']dithiophene-4-carboxylate, 3-Me-pydz = 3-methylpyridazine) has been prepared and characterized by single-crystal X-ray diffraction, density functional theory (DFT), and time-dependent DFT computations, UV-vis absorption and emission spectroscopy, and cyclic voltammetry (CV). The measured properties indicate the lack of electronic communication in the ground state between the CPDT and the rhenium diazine moieties. Oxidative electropolymerization of 1, achieved by repeated potential cycling (-0.4 to +1.0 V vs Fc(+)/Fc, in acetonitrile) with different supporting electrolytes, on different electrodes, afforded an electroactive and stable metallopolymer (poly-1). In situ measurements of the mass of the growing film (on a gold electrode, with an electrochemical quartz microbalance) confirmed the regularity of the polymerization process. The polymer exhibits two reversible oxidation peaks of the thiophene chain and a broad irreversible reduction peak (-1.4 V, quite close to that observed for the reduction of monomer 1), associated with a remarkably delayed sharp return peak, of comparable associated charge, appearing in close proximity (+0.3 V) to the first oxidation peak of the neutral polythiophene chain. This charge-trapping effect can be observed upon repeated cycles of p and n doping, and the negative charge is maintained even if the charged electrode is removed from the solution for many hours. Electrochemical impedance spectroscopy showed that the main CV oxidation peak corresponds to facile charge transfer, combined with very fast diffusion of both electrons and ions within the polymer. In summary, poly-1 provides a new example of a metallopolymer, in which the conductive properties of the π-conjugated system are added to the redox behavior of the pendant-isolated complexes.