The First Intramolecular Charge Transfer Transition Based on 2-Ureido-4[1H]-pyrimidinone Binding Module

The first intramolecular charge transfer transition based on 2-ureido-4[1H]-pyrimidinone binding module was reported.     

水热反萃法制备纳米α-Fe2-O3

氧化铁;环烷酸;制备;水热反萃法制备纳米α-Fe2-O3     

Versatile photosensitization system for 1O2-mediated oxidation of alkenes based on nafion-supported platinum(II) terpyridyl acetylide complex

[structure: see text] Platinum(II) terpyridyl acetylide complex (1) was incorporated into Nafion membranes as a photosensitizer, and the Nafion was immersed in an aqueous or organic solution of 7-dehydrocholesterol, alpha-pinene, or cyclopentadiene. This photosensitizer system can generate singlet oxygen ((1)O(2)) in high quantum yield to oxidize the alkenes in the solution outside the Nafion and can be easily removed from the reaction vessel at the end of the photooxidation.     

Synthesis and Luminescent Properties of an Acetylide-Bridged Dinuclear Platinum(II) Terpyridyl Complex

Introduction Luminescent coordinatively unsaturated platinum(II) complexes are appealing from photochemical and pho-tophysical perspective.1,2 In particular, platinum(II) ter-pyridyl complexes have attracted considerable attention due to their rich spectroscopic2a-d and biological proper-ties.2a,e-g However, the development of the photochem-istry of these complexes is limited by their short-lived MLCT excited state in solution at room temperature. The lack of emission originates from low-l…     

Confined space-controlled hydroperoxidation of trisubstituted alkenes adsorbed on pentasil zeolites

Photosensitized oxidation of trialkylalkenes 2-methyl-2-pentene (1), 1-methylcyclohexene (2), trans-3-methyl-2-pentene (3), cis-3-methyl-2-pentene (4), and 2-methyl-2-butene (5) included in the internal framework of Na-ZSM-5 zeolites was investigated. The zeolite samples having adsorbed the alkenes were suspended in isooctane, and the sensitizer, tetraphenylporphyrin (TPP), was dissolved in the solution. Singlet oxygen produced in the solution diffused into the internal framework of the zeolites and reacted with alkenes. For all the substrates studied, the ene-type allylic hydroperoxides were obtained in a highly regioselective manner. The regiochemistry for 1-4 in favor of the allylic hydrogen abstraction from the largest substituents is in contrast to their photooxidation within the dye-supported zeolite Na-Y, where the secondary hydroperoxides are preferentially produced. The tight confinement of the alkenes within the narrow channels of the ZSM-5 zeolites is likely to be responsible for this selectivity.     

Photoinduced intramolecular electron transfer and triplet energy transfer in a steroid-linked norbornadiene-carbazole dyad

Bichromophoric compound 3 beta-((2-(methoxycarbonyl)bicyclo[2.2.1]hepta-2,5-diene-3-yl)carboxy)androst-5-en-17 beta-yl-[2-(N-carbazolyl)acetate] (NBD-S-CZ) was synthesized and its photochemistry was examined by fluorescence quenching, flash photolysis, and chemically induced dynamic nuclear polarization (CIDNP) methods. Fluorescence quenching measurements show that intramolecular electron transfer from the singlet excited state of the carbazole to the norbornadiene group in NBD-S-CZ occurs with an efficiency (Phi SET) of about 14 % and rate constant (kSET) of about 1.6 x 10(7) s-1. Phosphorescence and flash photolysis studies reveal that intramolecular triplet energy transfer and electron transfer from the triplet carbazole to the norbornadiene group proceed with an efficiency (TET + TT) of about 52 % and rate constant (kTET + kTT) of about 3.3 x 10(5) s-1. Upon selective excitation of the carbazole chromophore, nuclear polarization is detected for protons of the norbornadiene group (emission) and its quadricyclane isomer (enhanced absorption); this suggests that the isomerization of the norbornadiene group to the quadricyclane proceeds by a radical-ion pair recombination mechanism in addition to intramolecular triplet sensitization. The long-distance intramolecular triplet energy transfer and electron transfers starting both from the singlet and triplet excited states are proposed to proceed by a through-bond mechanism.     

含二茂铁基的硫代碳酰腙和缩氨基硫脲的合成

硫代碳酰腙和氨基硫脲衍生物具有一定的生理活性,可作为某些金属离子的特效试剂,本文报道在乙醇-醋酸介质中通过取代氨基硫脲,硫代碳酰腙与不同的二茂铁衍生物缩合,合成了新的缩氨基硫脲和硫代碳酰腙衍生物.     

Solution-processable graphenes by covalent functionalization of graphene oxide with polymeric monoamines

We develop here a simple wet chemistry to prepare covalent functionalized graphenes(FGs) through epoxide aminolysis especially under alkaline aqueous condition. Remarkably, a series of typical monoamines, such as industrial Huntsman Jeffamine~ M-2070 and M-2005 polymer with hydrophilic or hydrophobic polyetheramine chains, positively-charged 2-amino-N,N,Ntrimethylpropanaminium,negatively-charged sulfanilic acid, even oligopeptide sequence, can be effectively grafted on the platelets of graphene oxide precursor with covalent functionalization and partially reduced features. This strategy provides the researchers a facile and convenient approach to design and synthesize solution processable, biocompatible and functionalized graphenes for the potent applications in electronic inks, drug carriers and biomedicines. Expansion of the current study is actively ongoing in our laboratory.     

问题引导法提高学生学习主动性的探索与实践*——以大学化学混合式教学为例

建设具有创新性、高阶性和挑战度的“金课”,是当代创新型人才培养的必然要求。大学化学是本校非化学类理工科专业基础课,相比于数学和物理,学生重视不足,导致教学效果不理想。为了解决这一问题,采取以学生为主的混合式教学模式,通过设置基础性、应用性及创新性问题,引导学生分层次解决,提高学生参与主动性。所设置的应用性问题包括科技前沿、专业相关、社会热点等,以增加内容的深度和广度,激发学生探索的兴趣。通过实验方案设计及实验检验培养学生的创新思维。采取累加式进行教学效果评价,实践表明该混合式教学模式能显著提高学生自主学习能力和兴趣,提高教学效果。     

Multiple-State Emissions from Neat,Single-Component Molecular Solids: Suppression of Kasha's Rule

Three rigid and structurally simple heterocyclic stilbene derivatives, (E)-3H,3′H-[1,1′-biisobenzofuranylidene]-3,3′-dione, (E)-3-(3-oxobenzo[c] thiophen-1(3H)-ylidene)isobenzofuran-1(3H)-one, and (E)-3H,3′H-[1,1′-bibenzo[c] thiophenylidene]-3,3′-dione, are found to fluoresce in their neat solid phases, from upper (S₂) and lowest (S₁) singlet excited states, even at room temperature in air. Photophysical studies, single-crystal structures, and theoretical calculations indicate that large energy gaps between S₂ and S₁ states (T₂ and T₁ states) as well as an abundance of intra and intermolecular hydrogen bonds suppress internal conversions of the upper excited states in the solids and make possible the fluorescence from S₂ excited states (phosphorescence from T₂ excited states). These results, including unprecedented fluorescence quantum yields (2.3–9.6 %) from the S₂ states in the neat solids, establish a unique molecular skeleton for achieving multi-colored emissions from upper excited states by “suppressing” Kasha's rule.