Search

Mechanically responsive materials (MRMs) usually showing observable changes in emission intensity (mechanochromic) under force stimuli have garnered increasing interest due to their broad range of potential applications. Relative to usual mechanochromic materials, a kind of alternative MRMs with changeable lifetime upon force stimuli in terms of mechanodecay is proposed. A catalog of novel MRMs with both mechanochromic and mechanodecay characteristics is reported. Halogen‐free semicrystalline polymers doped with chromophores showing bright and ultralong room‐temperature phosphorescence (RTP) under ambient conditions are facilely fabricated through melt blending approaches. Upon being stretched or compressed, the RTP polymers show abundant changes in fluorescence intensity, emission color, RTP intensity, and RTP lifetime. Such RTP polymers with multiple strain‐responsive visual signals offer a kind of new MRMs useful for visually sensing the deformation of materials. Leveraging remarkable change in RTP lifetime under force stimuli, deformation process of polymers is investigated through phosphorescence lifetime and image analysis. Early damage warning for engineering polymers is achieved. Given the merits of high sensitivity, multiple visual signals, low cost, and simple operation, such RTP polymers provide a class of new MRMs useful for deformation sensing and early damage reporting of engineering materials. [ABSTRACT FROM AUTHOR]

A novel metal‐organic framework (MOF) containing one‐dimensional, Fe2+ chains bridged by dipyrazolate linkers and N,N‐dimethylformamide (DMF) ligands has been synthesized. The unusual chain‐type metal nodes feature accessible coordination sites on adjacent metal centers, resulting in motifs that are reminiscent of the active sites in non‐heme diiron enzymes. The MOF facilitates direct reduction of nitric oxide (NO), producing nearly quantitative yields of nitrous oxide (N2O) and emulating the reactivity of flavodiiron nitric oxide reductases (FNORs). The ferrous form of the MOF can be regenerated via a synthetic cycle involving reduction with cobaltocene (CoCp2) followed by reaction with trimethylsilyl triflate (TMSOTf). [ABSTRACT FROM AUTHOR]

A redox‐neutral S‐nitrosation of thiol has been achieved at a dicopper(I,I) center. Treatment of dicopper (I,I) complex with excess NO. and thiol generates a dicopper (I,I) di‐S‐nitrosothiol complex [CuICuI(RSNO)2]2+ or dicopper (I,I) mono‐S‐nitrosothiol complex [CuICuI(RSNO)]2+, which readily release RSNO in 88–94 % yield. The S‐nitrosation proceeds by a mixed‐valence [CuIICuIII(μ‐O)(μ‐NO)]2+ species, which deprotonates RS‐H at the basic μ‐O site and nitrosates RS− at the μ‐NO site. The [CuIICuIII(μ‐O)(μ‐NO)]2+ complex is also competent for O‐nitrosation of MeOH. A rare [CuIICuII(μ‐NO)(OMe)]2+ intermediate was isolated and fully characterized, suggesting the S‐nitrosation may proceed through the intermediary of analogous [CuIICuII(μ‐NO)(SR)]2+ species. This redox‐ and proton‐neutral S‐nitrosation process is the first functional model of ceruloplasmin in mediating S‐nitrosation of external thiols, with implications for biological copper sites in the interconversion of NO./RSNO. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of palladium complexes bearing an N‐heterocyclic carbene (NHC)‐sulfonamide bidentate ligand and their application in ethylene oligomerization and ethylene/polar monomer cooligomerization. These catalysts could smoothly catalyze ethylene oligomerization and ethylene/methyl acrylate cooligomerization albeit the performance was lower compared to that of a NHC–phenoxide catalyst. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 474–477 Palladium complexes bearing an N‐heterocyclic carbene–sulfonamide bidentate ligand were synthesized, characterized, and applied to ethylene oligomerization and ethylene/polar monomer cooligomerization. [ABSTRACT FROM AUTHOR]