Synthesis of palladium-bidentate complex and its application in Sonogashira and Suzuki coupling reactions

A new palladium-bidentate complex [m-C₆H₄(CH₂ImMe)₂(PdCl₂)] (III) was prepared in two steps. In the first step, [m-C₆H₄(CH₂ImMeAgCl)₂] (II) (Im = imidazole moiety) was obtained by reacting imidazolium salt [m-C₆H₄(CH₂ImMe)₂]Cl₂ (I) (prepared by quaternisation of Nmethylimidazole with 1,3-bis(chloromethyl)benzene) and Ag₂O in CH₂Cl₂. In the next step, treatment of (II) with Pd(CH₃CN)₂Cl₂ afforded complex III which was evaluated for its catalytic activity for C-C bond-formation reactions by examining the coupling reaction of 3-iodoanisole with phenylacetylene in the Sonogashira reaction. In addition, 3-methoxybiphenyls were obtained with good to excellent yields by Suzuki coupling reactions of 3-iodoanisole with phenylboronic acids or phenylborates salts in the presence of this complex.     

Production of γ by 194 GeV/c negative pions on tungsten

On the basis of 2000 ?, ?′ and ?″ events obtained in π^?-W interactions at 194 GeV/c we extract a value for the cross section times the branching ratio of B_μμσ = (0.96±0.04±0.17) pb nucleon^?1. The $\text{(?′ + ?″)}\text{?}$ ratio is found to be 0.53 ± 0.19. The observed differential x_F and P_T distributions are compared with those of the Drell-Yan continuum, and the cross section and the x_F distribution are compared with theoretical predictions.     

Stabilization of the rotating disk-beam system with a delay term in boundary feedback

In this article, the stabilization problem of a rotating disk-beam system is addressed. It is assumed that the flexible beam is free at one end, whereas the other end is attached to the center of the rotating disk whose angular velocity is time-varying. The proposed feedback law consists of a torque control which acts on the disk, whereas a delayed boundary force control is exerted at the free end of the beam. Thereafter, it is proved that the presence of such controls in the system guarantees the exponential stability of the system under a realistic smallness condition on the angular velocity of the disk as well as the feedback gain in the delay term. This result is illustrated by numerical examples.     

On p-tuples of equi-isoclinic 3-spaces in the Euclidean space

In this paper we show on the one hand that ?⁸ contains two congruence classes of sextuples of equi-isoclinic 3-subspaces, whereas no such 7-tuple exists and on the other hand, we give the list of all regular p-tuples of equi-isoclinic 3-subspaces.     

Reactivity studies on 4‐aminopyrones: Access to benzimidazole and benzimidazolone derivatives

Reaction of pyrone 1a or tetronic acid 1b with o‐phenylenediamine derivatives gave enaminone compounds 2 . When reacting with different electrophiles, these intermediates allowed versatile access to different heterocyclic structures: when DMA derivatives or triphosgene was used, cyclization occurred through nitrogen, leading to benzimidazoles 3 and benzimidazolones 4 , respectively, while reaction with benzaldehyde yielded benzodiazepines 5 .     

Prediction of the cloud point of polyethoxylated surfactants and their mixtures by the thermodynamic model of Flory-Huggins-Rupert

The cloud point curves of polyethoxylated surfactants are established experimentally. These experimental data are preliminary to the development of the cloud point extraction process, which appears as an interesting alternative to the usual solvent extraction unit operation. Starting from the thermodynamic model developed by Flory and Huggins for phase separation of polymer aqueous solutions, this paper aims at the prediction of cloud point curves. In this work, Rupert’s approach is extended to commercial nonionic surfactants, mixtures of homologous species, namely a few alkylphenol and alcohol ethoxylates. The limit of such an approach is clearly demonstrated, provided that a fitting parameter is finally required for a successful model application to pilot-plant manufactured surfactants, like C₈ΦE_n (n?=?7.5, 10, 12), C₉ΦE_n (n?=?8, 10, 12), C₁₂E₄, C₁₂E₆ and commercial Tergitol 15-S-7 (linear C₁₂-C₁₄ secondary alcohol with an average of 7 ethylene oxide units).GRAPHICAL ABSTRACT