离子液体降低FCC汽油烯烃体积分数的研究

向FCC汽油中分别加入两种与FCC汽油不互溶的Lewis超强酸性离子液体\[Bmim\]Cl-AlCl3 和 \[R4N\]Cl-AlCl3形成液-液两相催化降烯烃体系。结果表明：在汽油辛烷值基本保持不变的基础上,FCC汽油的烯烃体积分数分别下降14.7%和13.1%, 均达到我国新配方汽油规定的烯烃体积分数v<35%的新标准。对离子液体降低FCC汽油的机理及影响因素进行了详细研究。结果表明,正是由于具备Lewis超强酸性的离子液体催化的烯烃与烷烃的烷基化、烯烃与芳烃的烷基化以及烯烃的二聚反应使得FCC汽油中烯烃体积分数显著下降。     

以炔烃衍生物为底物的联烯合成研究进展

联烯是一类含有累积双键的不饱和化合物, 因其具有重要的生理、药理活性及多种反应活性, 在有机合成中得到了广泛的应用; 随着对联烯性质的深入研究, 联烯的合成方法也日益丰富且各具特色, 其中炔烃衍生物已成为联烯合成的重要前体. 综述了以炔烃衍生物为底物, 经SN2取代、SN2-还原、1,4-加成、迁移、过渡金属催化、开环以及光环化等方式合成联烯的研究进展, 探讨了各种反应历程的特点及其影响因素.     

Copper- and base-free Sonogashira-type cross-coupling reaction of triarylantimony dicarboxylates with terminal alkynes under an aerobic condition

A simple copper- and base-free palladium-catalyzed Sonogashira-type cross-coupling by the use of triarylantimony dicarboxylates is described. Reaction of triarylantimony diacetates with terminal alkynes in the presence of 1 mol % of PdCl₂(PPh₃)₂ catalyst led to the formation of cross-coupling products in good to excellent yields. The reaction proceeded effectively under an aerobic condition, in that two of the three aryl groups on antimony could be transferred to the coupling products, whereas only one of them was involved in the reaction in an argon atmosphere. The reaction is sensitive to the electronic nature of the diacetates, and those bearing an electron-withdrawing group on the aromatic ring showed higher reactivity than those having an electron-donating group.     

Gold(I)-catalyzed arylmethylation of terminal alkynes

AuCl/AgOTf catalyzes the reaction of terminal alkynes with aryl trichloroacetimidate to afford arylmethylation products in moderate to good yields.     

Alkyne‐Promoted H2 Loss in a Metallaborane: Nido‐to‐Closo Cluster Transformation and sp C?H Bond Oxidative Addition

A sensitive cluster : The labile rhodathiaborane [(PPh₃)₂(H)‐nido‐RhSB₉H₉(NC₅H₅)] combines the redox and coordinative flexibility of the {(PPh₃)₂(H)Rh} fragment with the capability of the 11‐vertex rhodathiaborane cluster to undergo oxidative nido‐to‐closo transformations induced by coordination of alkynes to the metal centre, which leads to hydrogenation of the triple bond, dehydrogenation of the cluster and oxidative addition of sp C? H bonds.

     

Synthesis,Properties and Formation of (RCp)Co‐ and (RCp)Rh‐Stabilized[4.8]3Cyclacene Derivatives

Metal‐stabilized belts : A torus, 3 , consisting of three four‐ and three eight‐membered conjugated rings and stabilized by (RCp)Co‐ and (RCp)Rh‐ units, was generated by irradiation of [(RCp)Co(CO)₂] and [(RCp)Rh(C₂H₄)₂], respectively, and 1 .

     

Factors affecting the dimerization of persistent nitrogen‐centered 1‐phenyl urazole radicals to tetrazanes

1‐Phenyl urazole radicals are persistent air‐stable nitrogen‐centered radicals that engage in an equilibrium with the corresponding N―N tetrazane dimers in solution. While the equilibrium typically weakly favors the dimer form, for some 1‐phenyl urazole radicals bearing substituents at the ortho position of the benzene ring, the equilibrium instead strongly favors the dimer form. With the recent surge of interest in the properties and potential applications of heterocyclic radicals, the factors that affect this equilibrium are important to determine. We examined the effect of the extent of ortho substitution (none, 1, or 2 substituents) on the equilibrium by experimentally using variable temperature ¹H nuclear magnetic resonance and UV‐visible spectroscopy in addition to supporting computational investigations at the (U)B3LYP/6‐311G(d,p) level of theory. We confirmed that the equilibrium generally favored the dimer in all cases. However, the equilibrium was more favorable towards dimer formation for urazole radicals substituted with 1 and 2 ortho substituents on the aromatic ring. The activation enthalpies for dissociation of singly substituted dimers were greater than that for dimers without ortho substituents, but lower than that for doubly substituted dimers. The greater preference for dimer formation for the ortho‐substituted urazole radicals is attributed to a greater enthalpic advantage for N―N bond formation. This advantage may be traced to a higher concentration of spin density on the urazole unit of the radicals and a lesser deformation energy required for N―N bond formation.     

Synthesis of Unsymmetrical 1,3‐Diynes via Pd/Cu‐Catalyzed Cross‐Coupling of Terminal Alkynes at Room Temperature

A facile and practical synthetic route of unsymmetrical 1,3‐diynes via the PdCl/CuI catalyzed oxidative coupling of two different terminal alkynes has been developed by using 3‐(diphenylphosphino)propanoic acid as a ligand in the presence of oxygen. This system is suitable for not only aromatic alkynes but also heteroaromatic and aliphatic alkynes which were transformed into the corresponding unsymmetrical 1,3‐diynes in moderate to good yields at room temperature. Moreover, the unsymmetrical 1,3‐diynes were also obtained on a multi‐gram scale. Mechanistic studies suggest that oxygen plays a key role in the catalytic cycles.     

Improved Thin‐Film Transistor Performance Through a Melt of Poly(para‐phenyleneethynylene)

The performance of polymer field‐effect transistors (PFETs) based on short rigid rod semiconducting poly(2,5‐didodecyloxy‐p‐phenyleneethynylene) (D‐OPPE) is highlighted. The controlled heating and cooling of thin films of D‐OPPE allows for a recrystallization from the melt, boosting the performance of D‐OPPE‐based transistors. The improved film properties induced by controlled annealing lead to a hole field‐effect mobility around 0.014 cm² V⁻¹ s⁻¹, an on/off ratio of 10⁶, a sub‐threshold swing of 3 V dec⁻¹ and a threshold voltage of −35 V, employing a poly(methyl methacrylate) (PMMA) gate dielectric. Thus, PFETs out of D‐OPPE compete now with spin‐coated, polycrystalline poly(3‐hexylthiophene)‐based PFETs.