2-(ω-联苯基多亚甲基)-5-联苯基-1,3,4-二唑的荧光光谱研究

本文测定了双荧光团化合物2-(ω-联苯基多亚甲基)-5-联苯基-1,3,4-二唑及其模型化合物2-甲基-5-联苯基-1,3,4-二唑和2,5-二联苯基-1,3,4-二唑的荧光光谱.对分子内,分子间激基缔合物和激基复合物的形成进行了研究,并对分子构型与形成分子内激基复合物之间关系作了初步探讨.从实验结果得到,亚甲基桥链的碳数为奇数时容易形成分子内激基复合物.     

Conformations of the 10-membered Ring in 5, 10-Secosteroids. II. (E)-3α-Acetoxy-5, 10-seco-1 (10)-cholesten-5-one and (E)-5, 10-seco-1 (10)-cholestene-3, 5-dione

(E)-3α-Acetoxy-5, 10-seco-1(10)-cholesten-5-one ( 3 ) was synthesized by fragmentation of 3α-acetoxy-5α-cholestan-5-ol ( 1 ) using the photochemical version [3] of the lead tetraacetate reaction [4], and transformed into the corresponding 3-oxo-compound ( 5 ). Two conformations ( A and B ) were deduced for the 10-membered ring of 3 by analysis of the ¹H- and ¹³C-NMR. spectra in toluene. The major conformation ( A ) corresponds to that found in the solid state by X-ray analysis. According to its NMR. spectra in toluene, the medium-sized ring of the diketone 5 exists also predominantly in two conformations, the major one being analogous to A (the solid-state conformation of the 3β-acetoxy isomer ( 9 ) [1]) and the minor one to A (see above). The stereochemistry of the acidcatalyzed and thermal cyclisations of 3 as well as of the corresponding 5-oxime is discussed in terms of conformational factors.     

Crystal Structure of 4, 5-trans-2-Amino-1, 3, 3-tricyano-4, 5-di (4-chlorophenyl)cyclopentene. Ethanol. Monohydrate

1mTRODUCT10NSincethetimeKaganhasdem0nstratedasimplepreparationofsamariumdiio-didefromsamariummetaland1,2-diiodoethanet1),SmI2hasbeenwidelyusedinsyntheticreactionst23.Thereactivityofsamariumdiiodidetowardsvariousnitrogen-containingcomP0undshasalreadybeenexamined.Thereare,toourknowledge,noliteratureexamplesforthereductionofcyanogrouptoproduceaminowiththisreagent.Inthispaper,wediscussedthecrystalstructureofthetitlecomP0undsyn-thesizedbythereactionofsamariumdii0didereagentwithp-chloroben-zyli…     

Conformations of the Ten-membered Ring in 5, 10-Secosteroids. III: (Z)-3β- and (Z)-3α-Hydroxy-5, 10-seco-1 (10)-cholesten-5-one Esters and (Z)-5, 10-seco-1 (10)-Cholestene-3, 5-dione

(Z)-3β-Acetoxy- and (Z)-3 α-acetoxy-5, 10-seco-1 (10)-cholesten-5-one ( 6a ) and ( 7a ) were synthesized by fragmentation of 3β-acetoxy-5α-cholestan-5-ol ( 1 ) and 3α-acetoxy-5β-cholestan-5-ol ( 2 ), respectively, using in both cases the hypoiodite reaction (the lead tetraacetate/iodine version). The 3β-acetate 6a was further transformed, via the 3β-alcohol 6d to the corresponding (Z)-3β-p-bromobenzoate ester 6b and to (Z)-5, 10-seco-1 (10)-cholestene-3, 5-dione ( 8 ) (also obtainable from the 3α-acetate 7a ). The ¹H-and ¹³C-NMR. spectra showed that the (Z)-unsaturated 10-membered ring in all three compounds ( 6a , 7a and 8 ) exists in toluene, in only one conformation of type C ₁, the same as that of the (Z)-3β-p-bromobenzoate 6b in the solid state found by X-ray analysis. The unfavourable relative spatial factors (interdistance and mutual orientation) of the active centres in conformations of type C ₁ are responsible for the absence of intramolecular cyclizations in the (Z)-ketoesters 6 and 7 ( a and c ).     

Rate Constants for the Reactions of NO3 and SO4 Radicals with Oxalic Acid and Oxalate Anions in Aqueous Solution

Rate constants for the reactions of NO3 and SO4 radicals with oxalic acid and oxalate anions in aqueous solution have been measured using pulse radiolysis and laser flash photolysis.     

Near-Infrared Light-Triggered Chlorine Radical (.Cl) Stress for Cancer Therapy

Free radicals with reactive chemical properties can fight tumors without causing drug resistance. Reactive oxygen species (ROS) has been widely used for cancer treatment, but regrettably, the common O₂ and H₂O₂ deficiency in tumors sets a severe barrier for sufficient ROS production, leading to unsatisfactory anticancer outcomes. Here, we construct a chlorine radical (^.Cl) nano-generator with SiO₂-coated upconversion nanoparticles (UCNPs) on the inside and Ag⁰/AgCl hetero-dots on the outside. Upon near-infrared (NIR) light irradiation, the short-wavelength emission UCNP catalyzes ^.Cl generation from Ag⁰/AgCl with no dependence on O₂/H₂O₂. ^.Cl with strong oxidizing capacity and nucleophilicity can attack biomolecules in cancer cells more effectively than ROS. This ^.Cl stress treatment will no doubt broaden the family of oxidative stress-induced antitumor strategies by using non-oxygen free radicals, which is significant in the development of new anticancer agents.     

Isostructural triazenido complexes of first row transition metals. Part 2. Synthesis and properties of [(η5-C5H5)L(RN3R)CoIII]PF6, L = PEt3, PPh3, P(OMe)3 and P(OPh)3

Summary The synthesis and properties of the [(⁵-C₅H₅)L(RN₃R)Co^III]PF₆ complexes, with L = PEt₃, PPh₃, P(OMe)₃ or P(OPh)₃, are reported. A six coordinate configuration containing a chelating triazenido ligand is proposed which is isostructural with the known complexes of iron and nickel.The spectroscopic properties of the isoelectronic Co and Fe complexes, (⁵-C₅H₅)L(RN₃R)M, are compared in relation to the charge on the central metal atom. The complex with L = CO could not be prepared, but the carbonyl inserted product (⁵-C₅H₅)(L{RNNN(R)C(O)}Co was isolated. In one of the reactions, the novel ring-bound triphenylphosphine complex, [⁵-C₅H₅)(⁵-C₅H₄PPh₃)Co^III](PF₆)₂, was isolated as a side product. The mechanism of this reaction is discussed.