NOVEL HALOGENATION OF THIOPHENES WITH BENZENESELENINYL CHLORIDE AND ALUMINUM HALIDE

Abstract

In the presence of aluminum halide, benzeneseleninyl chloride is an efficient Regioselective halogenating reagent for heterocyclic compounds such as thiophene, 2methylthiophene. 3-methylthiophene, 2,5-dimethylthiophene, and furan. In the case of pyrrole, no halogenated product was obtained. A plausible reaction mechanism involving a positive halogen intermediate is proposed.     

Simultaneous manifestation of metallic conductivity and single-molecule magnetism in a layered molecule-based compound

Single-molecule magnets (SMMs) show superparamagnetic behaviour below blocking temperature at the molecular scale, so they exhibit large magnetic density compared to the conventional magnets. Combining SMMs and molecular conductors in one compound will bring about new physical phenomena, however, the synergetic effects between them still remain unexplored. Here we present a layered molecule-based compound, β′′-(BEDO-TTF)₄ [Co(pdms)₂]·3H₂O (BO4), (BEDO-TTF (BO) and H₂pdms are bis(ethylenedioxy)tetrathiafulvalene and 1,2-bis(methanesulfonamido)benzene, respectively), which was synthesized by using an electrochemical approach and studied by using crystal X-ray diffraction. This compound simultaneously exhibited metallic conductivity and SMM behaviour up to 11 K for the first time. The highest electrical conductivity was 400–650 S cm⁻¹ at 6.5 K, which is the highest among those reported so far for conducting SMM materials. Furthermore, antiferromagnetic ordering occurred below 6.5 K, along with a decrease in conductivity, and the angle-independent negative magnetoresistance suggested an effective electron correlation between the conducting BO and Co(pdms)₂ SMM layers (d–π interactions). The strong magnetic anisotropy and two-dimensional conducting plane play key roles in the low-temperature antiferromagnetic semiconducting state. BO4 is the first compound exhibiting antiferromagnetic ordering among SMMs mediated by π-electrons, demonstrating the synergetic effects between SMMs and molecular conductors.

A metallic single-molecule magnet was synthesised demonstrating simultaneous metallic conduction and excellent SMM properties at the same temperature range for the first time, with potential applications in molecule-based quantum spintronics.     

Direct Enantioselective Vinylogous Mannich Reaction of Ketimines with γ‐Butenolide by Using Cinchona Alkaloid Amide/Zinc(II) Catalysts

A direct enantioselective vinylogous Mannich reaction of ketimines with γ‐butenolide has been developed. Good yields and enantioselectivities were observed for the reaction of various ketimines by using a cinchona alkaloid amide/Zn(OTf)₂ catalyst and Et₃N. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts.     

Preparation and Free-Radical Polymerization of 2,4-Dichloro-6-(p-Vinylphenyl)-1,3,5-triazine as a Reactive Monomer Containing Two Replaceable Groups

Abstract

A new monomer containing two replaceable groups, 2,4-dichloro-6-(p-vinylphenyl)-1,3,5-triazine (DCVT) was prepared by the reaction of p-vinylphenylmagnesium chloride with cyanuric chloride. This monomer was polymerized readily in benzene by AIBN at 60°C. From the copolymerization with styrene, Q and e values of DCVT were obtained as Q = 2.42 and e = 0.08. An insoluble terpolymer prepared from DCVT, styrene, and divinylbenzene was treated with several nucleophilic reagents, including sodium methoxide, sodium methylmercaptide, dimethylamine, and triethylphosphite, to afford the corresponding polymers in high conversions.