Exploratory Investigations Probing a Preparatively Versatile, Pyridinium Salt Photoelectrocyclization-Solvolytic Aziridine Ring Opening Sequence

A novel pyridinium salt photoelectrocyclization-nucleophilic bicyclic aziridine ring opening reaction sequence has been investigated in order to determine its preparative potential. N-Alkylpyridinium perchlorates were found to undergo photoinduced electrocyclization upon irradiation in nucleophilic solvents, such as H(2)O and MeOH, to efficiently produce 6-alkyl-6-azabicyclo[3.1.0]hex-2-en-4-yl alcohols and ethers. The bicyclic aziridine photoproducts react with a number of different nucleophiles (e.g., H(2)O, MeOH, AcOH, AcSH) under acid-catalyzed conditions to produce 5-(nucleophile-substituted)-4-(alkylamino)cyclopenten-3-yl alcohols and ethers. The aziridine ring opening processes are both regioselective and stereoselective, yielding trans,trans-trisubstituted cyclopentenes exclusively, apparently as a consequence of the operation of an SN(2) mechanism. The effects of C-alkyl substitution on the regiochemistry of the pyridinium cation photocyclization reaction were briefly probed, and a method was developed to produce trans,cis-trisubstituted cyclopentenes by use of this tandem preparative sequence.     

Chlorpromazine hydrochloride as an analytical reagent : A new indicator for titrations with very dilute ceric sulphate solutions

Chlorpromazine hydrochloride is proposed as an indicator for the microtitration of iron(II), arsenic(III), ascorbic acid and hydroquinone with 0.0005–0.001 N ceric sulphate; the indicator blanks are small. The colorimetric déterminations of μg quantities of cerium(lV) and arsenic(III) using the same reagent are also described.     

Solid Phase Synthesis of 4H-Pyrimido[2,1-b] Benzothiazol-4-ones from Resin-Bound Cyclic Malonic Ester

The solid phase synthesis of 4H-pyrimido[2,1-6] benzothizaol-4-ones has been reported.     

相转移催化元素硫的歧化反应

本工作将相转移催化(PTC)应用于元素硫歧化反应,大大降低了反应温度,提高了反应速度。该反应被证实与熔态硫在水溶液中的歧化相同,即4S+6OH~-=2S~(2-)+S_2O_3~(2-)+3H_2O。比较了四乙基铵、四丁基铵、十六烷基三甲基铵和三辛基甲基铵四种相转移催化剂及四氯乙烯、二甲苯和四氯乙烷三种溶剂的影响。讨论了本体系相转移催化的证据。为改进以元素硫歧化反应为基础的提取冶金过程提供了依据。     

Synthesis and characterization of Ru2(DMBA)4X2 (X = CN, N3, N(CN)2, I): controlling structural, redox, and magnetic properties with axial ligands

Metathesis reactions between Ru(2)(DMBA)(4)Cl(2) (DMBA = N,N'-dimethylbenzamidinate) and MX (M = Na and K) yielded bis-adduct derivatives Ru(2)(DMBA)(4)X(2) (X = CN (1), N(3) (2), N(CN)(2) (3)). Metathesis reactions between Ru(2)(DMBA)(4)(NO(3))(2) and KI resulted in Ru(2)(DMBA)(4)I(2) (4). Compound 1 is diamagnetic, while compounds 2-4 are paramagnetic (S = 1). Both compounds 1 and 2 undergo two reversible one-electron processes, an oxidation and a reduction, while compound 3 features a quasireversible reduction. Single-crystal X-ray diffraction studies revealed that the Ru-Ru bond lengths are 2.4508(9), 2.3166(7), 2.304[1], and 2.328(1) A for compounds 1-4, respectively. Structural and electrochemical data clearly indicate that the axial ligands impart a significant influence on the electronic structures of diruthenium species.     

Synthesis of 2‐Dihydrooxadiazolinyl Chromones

Reactions of the substituted 2‐formyl chromones with aroylhydrazines gave corresponding 2‐(aroylhydrazonomethylidyne) chromones. Then 2‐(3′‐acetyl‐5′‐aryl‐2′,3′‐dihydro‐1′,3′,4′‐oxadiazol‐2′‐yl) chromones were prepared by these 2‐(aroylhydrazonomethylidyne) chromones under refluxing with Ac₂O. All target compounds were characterized through elemental analysis and IR, ¹H NMR, MS.     

Carbonyldinitrosyltris(fluorosulfato)tungstate(II) and ‐Molybdate(II) Anions: Synthesis,Spectroscopy, and Density Functional Theory Calculations

Carbonyldinitrosyltris(fluorosulfato)tungstate(II) and ‐molybdate‐(II) anions, [fac‐M(CO)(NO)₂(SO₃F)₃]^? (M=W, Mo), which are novel weakly coordinating anions that contain a metal carbonyl/nitrosyl moiety, have been generated in fluorosulfonic acid and completely characterized by multinuclear NMR, IR, and Raman spectroscopy as well as ESI mass spectrometry. ESI MS measurements performed for the first time on a superacidic solution system unambiguously reveal the formation of the monoanionic, mononuclear W and Mo complexes formulated as [M(CO)(NO)₂(SO₃F)₃]^? (M=W, Mo). Multinuclear NMR spectroscopic studies at natural abundance and ¹³C and ¹⁵N enrichment clearly indicate the presence of one CO ligand, two equivalent NO ligands, and two types of nonequivalent SO₃F^? groups in a 2:1 ratio. The IR and Raman spectra reveal that the two equivalent NO ligands have a cis conformation, thus indicating a fac structure. Density functional calculations at the B3LYP level of theory predict that these anions have a singlet ground state (¹A′) with a C_s symmetry along with C–O and N–O vibrational frequencies that are in agreement with the experimental observations. Mulliken population analysis shows that the monovalent negative charge is dispersed on the bulky sphere, the surface of which is covered by all the negatively charged O and F atoms with charge densities much lower than SO₃F^?, suggesting that [fac‐M(CO)(NO)₂(SO₃F)₃]^? (M=W, Mo) are weakly nucleophilic and poorly coordinating anions.     

13C NMR studies of molecular relaxation processes in polar fluids

A study of the dynamical molecular structure of a dilute polar fluid is reported, in which ¹³C spin-lattice relaxation times of decanol in deuterated cyclohexane are presented for the individual carbon atoms, and the results are discussed in the context of viscosity data of decanol in alkane systems. The two techniques provide complementary information about the mobility of the alcohol chains and the onset of multimer formation, which is also pertinent to the dynamics of electron solvation in the same systems.     

The Emission in the Acetone Photochemical System

The emission in the acetone photochemical system has been measured as a function of irradiating time and pressure. The emission yield generally increases with increase in irradiating time at both 3130 and 2654A. The increase of emission yields is due to the sensitized phosphorescence of the product biacetyl. The higher emission yield and lower biacetyl quantum yields at 3130A than that at 2654A support for that most of the excited acetone molecules are in the triplet state at 3130A.