Studies on sulfinato-dehalogenation XII.Sodium dithionite-initiated addition of N,N-diethyliododifluoroacetamide to multiple bonds

N,N-deithyl-iododifluoroacetamide 1 reacted with alkenes,alkynes in aqueous aceto- nitrile solutions of sodium dithionite and sodium hydrogen carbonate at room temperature to give the corresponding adducts,thus constituting a new method for introducing the CF_2 group into organic mol- ecules.Compound 1 reacted with conjugated olefins 2b,c to afford the iodine-free adducts 7b,c. The adducts 3d-f,from addition of 1 to alkenes 2d-f,could be converted into α,α-difluoro-γ- lactones 5d-f by treatment with silica gel.Compound 1 reacted with ethyl vinyl ether 2i to give aldehyde 8,and perfluoroalkyl or polyfluoroalkyl iodides reacted similarly.A radical mechanism was proposed for the addition reaction.Under the same condition,N,N-diethyl-bromodifluoroacetamide produced only the corresponding sulfinate Et_2NC(O)CF_2SO_2Na.

Organothorium complexes containing terminal metal-ligand multiple bonds

Organoactinide complexes containing terminal metal-ligand multiple bonds have received widespread attention over the past three decades. In the last few years, significant progress has been made in the synthesis and characterization of the imido, oxo, sulfido, and carbene-containing complexes of thorium. Such thorium complexes are of interest because of their unique structural properties, their potential application in novel group transfer reactions and catalysis, as well as their ability to engage the 5f orbitals in metal-ligand bonding. This short review summarizes the synthesis and reactivity of these thorium complexes.

A FACILE SYNTHESIS OF 2-TRIFLUOROMETHYLPYRROLE VIA 1,3-DIPOLAR CYCLOADDITION REACTION OF 2-TRIFLUOROMETHYLOXAZOLONE AND THE ACTIVATED CARBON-CARBON MULTIPLE BOND

The 1.3-dipolar cycloaddition reaction of 2-trifluoromethyl- oxazolone and the activated carbon-carbon multiple bond was studied and gave a convenient way to synthesize 2-trifluoromethylpyrrole derivatives.

PRICING OF MULTIPLE DEFAULTABLE BOND

In this paper a generalized defaultable bond pricing formula is derived by assuming that there exists a defaultable forward rate term structure and that firms in the economy interact when default occurs.Generally,The risk-neutral default intensity λ Q is not equal to the empirical or actual default intensity λ.This paper proves that multiple default intensities are invariant under equivalent martingale transformation,given a well-diversified portfolio corresponding to the defaultable bond.Thus one can directly apply default intensities and fractional losses empirically estimated to the evaluation of defaultable bonds or contingent claims.

Stabilizing Buried Interface via Synergistic Effect of Fluorine and Sulfonyl Functional Groups Toward Efficient and Stable Perovskite Solar Cells

The interfacial defects and energy barrier are main reasons for interfacial nonradiative recombination.In addition,poor perovskite crystallization and incomplete conversion of PbI_(2) to perovskite restrict further enhancement of the photovoltaic performance of the devices using sequential deposition.Herein,a buried interface stabilization strategy that relies on the synergy of fluorine(F)and sulfonyl(S=O)functional groups is proposed.A series of potassium salts containing halide and non-halogen anions are employed to modify SnO_(2)/perovskite buried interface.Multiple chemical bonds including hydrogen bond,coordination bond and ionic bond are realized,which strengthens interfacial contact and defect passivation effect.The chemical interaction between modification molecules and perovskite along with SnO_(2) heightens incessantly as the number of S=O and F augments.The chemical interaction strength between modifiers and perovskite as well as SnO_(2) gradually increases with the increase in the number of S=O and F.The defect passivation effect is positively correlated with the chemical interaction strength.The crystallization kinetics is regulated through the compromise between chemical interaction strength and wettability of substrates.Compared with Cl−,all non-halogen anions perform better in crystallization optimization,energy band regulation and defect passivation.The device with potassium bis(fluorosulfonyl)imide achieves a tempting efficiency of 24.17%.

Are Sc-C and Sc-P Bonds Reactive in Scandium Phosphinoalkylidene Complex？ Insights on a Versatile Reactivity

The peculiar electronic structure of scandium phosphinoalkylidene complex [LSc{C（SiMe3）PPh2}THF] （L=[MeC（NDIPP）CHC（NDIPP）Me]-）, DIPP= 2,6-（Pr）2C6H3） leads to an interesting versatile reactivity, which is demonstrated both experimentally and computationally. The complex undergoes [2＋2] cycloaddition reactions with alkynes, and easily activates various X-O bonds such as C-O of propylene oxide, N-O of 3,5-dimethylisoxazole, B-O of pinacolborane and Si-O of triethoxysilane. These reactions occur on the Sc-C bond of the phosphinoalkylidene complex. Interestingly, the Sc-P bond can also be activated as the presence of a Sc-C-P three center π interaction in the complex allows performing C-F activation of 2,6-difluoro- pyridine and 1,2 addition with imine or ketone. The complex also reacts with metal complexes, [（COD）RhCl]2 and （Ph3P）AuCl, to form structural intriguing heterobimetallic complexes.

Organophosphine bearing multiple hydrogen-bond donors for asymmetric Michael addition reaction of 1-oxoindane-2-carboxylic acid ester via dual-reagent catalysis

Multiple hydrogen bonds containing nucleophilic phosphines derived from dipeptide dual-reagents catalyzed asymmetric Michael addition reactions between indene esters and activated olefins in high yields and good to excellent enantioselectivities under mild reaction conditions.The success of current highly selective reactions should provide inspiration for expansion to other reactions and would open up new paradigms for the synthesis of indanone derivatives bearing chiral quaternary carbon centers.

The biomimetic design provides efficient self-healing of ultrahightough and damage-warning bio-based elastomer for protective clothing of metals

Facing the ubiquitous corrosion threat,the great significance of developing high-performance protective materials with the dual function of self-healing defects and self-warning damage is extremely challenging.Herein,inspired by the biological skin and pearls,we proposed that the biological polyurethanes(PU)embedded with multiple dynamic bonds(reversible hydrogen bonds and aromatic disulfide bonds)were combined with polydopamine(PDA)/1,10-phenanthroline(Phen)/graphene oxide(GO)(PPG)nanosheets(PDA encapsulated GO with Phen)to obtain a versatile nacre structure polymer with the interface hydrogen bond between PPG and PU matrix.The biomimetic polymer not only guarantees ultrahigh toughness(116.1 MJ·m^(-3))and abnormal elongation(2320%)but shows satisfactory repair performance(81%under 25℃ for 3 h),and the coating can accelerate damage recovery(87%)under near-infrared light(NIR)irradiation for 1 h due to the photothermal properties of PPG.The warning of damages in the coating can be enabled through the Phen chelation Fe^(2+)ions that bring in the corrosion reaction to produce a conspicuous red color,thereby achieving the active warning function of the bionic coating on defects for the first time.In addition,the electrochemical tests exhibit that the repair performance and protection effect of the biomimetic coating in 3.5 wt.%NaCl solution are also trustworthy,and this highly reliable bio-based bionic coating brings a revolutionary program to inaugurate multifunctional and high-performance intelligent materials under harsh environments.

Quadruple bonding of carbon in terminal carbides

Despite its four valence electrons,carbon can at most form triple bond in ordinary organic complexes.Quadruple bonds for carbon had been considered as impossible for a long time.Recently we showed that quadruple bonding is viable in a triatomic uranium carbide oxide molecule CUO,where the terminal C is quadruply bonded with U via its nearly unhybridized 2s-and2p-orbitals.Here we extend this new concept to a series of diatomic molecules consisting of tetravalent p-,d-,and f-elements and terminal carbide.Investigation has been focused on a series of CM-type molecules with possible quadruply-bonded carbon(QBC),CB?,CTi,CZr,CHf,CV+,CNb+,CTa+,and isoelectronic species of CUO.We have performed natural bond orbital(NBO),natural resonance theory(NRT),and atom-in-molecule(AIM)analyses at both density functional theory(DFT)and ab initio CASSCF levels to provide evidence for the feasibility of carbon quadruple bond in these systems.Our calculation results show that the C?M bond orders in these QBC species are comparable to that in CUO,indicating terminal carbides can have novel quadruple bonding when appropriate orbitals are available in the adjacent atoms.