STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ISE''''S (Ⅲ)——ERYTHROMYCIN ELECTRODES AND THEIR SELECTIVITY TOWARD QUATERNARY AMMONIUMS

Erythromycin sensitive electrodes have been proposed. Their selectivity toward quaternary ammoniums is described in terms of induction effect and steric hindrance effect: logKil=a_1I-a_2Z/R+a_0, where I is induction effect index, a_1,a_2 and a_0 are coefficients which depend on the electro-active material. A general formula has been suggested to relate the electrode selectivity to the carbon atom number (n) of the alkyl of the quaternary ammonium; logK_(ij)=A/2.7~R-B/(0.80+1.26n)+C, where A, B and C are coefficients which depend on the electro-actlve material, logK_(ij) tends to a limited value C when n increases.     

STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ISE''''S (Ⅶ)——PERFORMANCE AND THEORETICAL TREATMENT OF MICROCELLS CONNECTED IN SERIES

A new type of MCCS (microcells connected in series) has been constructed and its performances investigated. It has been applied to the determination of streptomycin. The sensitivity and accuracy have been increased significantly. A theoretical model for the error of determination using the MCCS has been suggested and proved experimentally using the Monte Carlo method, and the error model proposed in Ref. [1] revised.     

STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ION-SELECTIVE ELECTRODES TRIFLUOPERAZINE ION-SELECTIVE ELECTRODE

New ion-pair complexes of trifluoperazine with dialkylnaphethalene sulfonates, tetraphenylborate, nitro-arylsulfonates, heteropoly acids and halogeno-metal complex acids have been synthesized. Their extraction coefficients in the water-membrane solvent systems are determined to be>10~6 and electrode slopes approach the theoretical values. Systematical studies on electrode behaviours show that the electrode performances depend greatly on the dielectric constants of both the electrode membrane solvent and the sample solution background rather than on the kind of the ion-pair incorporated. For homolog membrane solvents, the extraction coefficient and the liquid-membrane electrode slope increase with the increasing dielectric constant of the solvent, the slopes are found to be related linearly to the inverse dielectric constants of the membrane solvents according to the formula: S=68.5—95.7 ε~(-1) (for n-alcohols), S=69.7—62.0 ε~(-1) (for o-phthalates). Similar relationship exists between slopes of both     

STUDIES ON THE LB FILM OF 2-HEPTADECYL IMIDAZOLECOORDINATING METAL IONS

The surface pressure—area isotherms(π—A curves) of 2—heptadecyl imidazole (HIM) Langmuir films at the subphases of deionized water and solutions containing metal ions such as Cu~(2+), Cd~(2+), Ca~(2+), Co~(2+), Ag~+ etc. have been studied. It was formed Langmuir film at the subphase containing Cu~(2+) or Ag~+ ions and its LB film was successfully deposited. The molecular and ionic total energies (E) and stabil. ity energies (△E) forming complexes were computed by CNDO/2 method. The computational results agreed with the experiments.     

STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ION-SELECTIVE ELECTRODES (Ⅱ)——SULPHA-DRUG SENSITIVE ELECTRODES USING QUATERNARY PHOSPHONIUM AND ARSONIUM COMPOUNDS

Ion-pair complexes of sulphonamide derivatives with quaternary phosphonium and quaternary arsonium have been synthesized and their electrode performances studied. It has been found that the electrode functions depend mainly on the site cation rather than on the anionic species and deteriorate in the order of cetyhrioctylammonium>cetyltriphenylphosphonium> cetyhriphenylarsonium. The electrode selectivity for different sulpha-drugs decreases in the order of sulphathiazole>sulphamethoxazole>sulphadimethoxine, sulphadoxine>sulphacetamide>sulphadiazine>sulphanilamide. Selectivity coefficients depend not only on the molecular connectivity index χ, but also on the electronic charge at the ionizing amide nitrogen atom σ and pK, according to the following formula: logK_(ij)=aχ+bσ—CpK_a—d. The quaternary phosphonium type electrodes have been suggested for use in the potentiometric determinations of sulpha-drugs.     

PERVAPORATION SEPARATION OF WATER-ACETIC ACID MIXTURES THROUGH AN-co-AA MEMBRANES TREATED WITH RARE EARTH METAL IONS

Pervaporation separation of water-acetic acid mixtures through Poly (AN-co-AA)membranes and rare earth metal ions treated Poly(AN-co-AA)membranes was investigatedfor the first time. The results showed that the treatment with rare earth metal ions couldgreatly improve the characteristics of the separation of water-acetic acid mixtures.     

KINETICS OF DEPOSITION OF METAL IONS TO ACTIVATED CARBON FIBERS (ACFs) WITH FLUIDIZATION

1. INTRODUCTION Study on the deposition of metal ions on ACFs indicated that such a process consists of several consecutive steps [1]: (1) transfer of the solvated ions (metal ions) from the bulk solution to the proximity of the ACFs surface; (2) absorpt…     

STUDIES ON 1,2,3-DIAZAPHOSPHOLE Ⅳ REACTION OF 1,2,3-DIAZAPHOSPHOLE WITH ALCOHOLS

Rapid addition of alcohols to 1,2,3-diazaphosphole 1 easily gave tricoordinatedphosphorus compounds,which were sulfurized to tetracoordinated phosphorus compounds.When ethylene glycol and aminoethanol were used separately to react with 1,the tricoordinatedphosphorus compounds which formed,rearranged to pentacoordinated phosphorus compoundsand the substituents at N_2 affected the rearrangement significantly.     

KINETICS OF DEPOSITION OF METAL IONS TO ACTIVATED CARBON FIBERS（ACFs)WITH FLUIDIZATION

The diffusion and mass transfer, reaction, integration and growth processes of the metalions on the activated carbon fibers (ACFs) are discussed. Based on the diffusion film theory, thediiffusion and the integration model are developed to describe the deposition processes of metal ionsfrom the solution to ACFs in the fiuidized beds. The model of heat transfer of this process isestablished to expound the important role-played in deposition processes by the influence of thereaction heat released at ACFs surface and the non-uniform temperature distribution caused byhydrodynamics.     

STUDIES ON POLYHALOALKANES Ⅳ. THE REACTION OF POLYFLUOROALKYL IODIDES WITH SILVER(I) SALTS

The conversion of polyfluoroalkyl iodides into the corresponding carboxylic acids by the reaction with silver (I) salts is described.     

STUDIES ON THE REACTION OF d-ACETAMIDCCINNAMAMIDE WITH TRIS(DIETHYLAMINO)PHOSPHINE

d-Acetamidocinnamamide do not react with P(OMe)_3, with P(NEt_2)_3 they give rise to 2-methyl-4-hydroxy-5-d-[bis(diethylamino)phosphoryl] benzyl imidazole.The pathway is studied for the formation of Ⅰ. The two intermediates(Ⅱ) are isolated.The structures of Ⅰ and Ⅱ are confirmed by IR, ~1H NMR, ~(31)P NMR, Ms.     

CONFORMATIONAL CHARACTERISTICS OF POLY(ACRYLIC ACID) AND POLY(METHACRYLIC ACID)

A full-relaxation optimization of molecule and the Dreiding force field are employed toobtain the geometry parameters and the conformational energy surfaces of meso or racemicdyad of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA). Three differentcarbonyl-bond orientations of side-groups resulted in the differences in depth of potentialwells in their energetic contours for a meso or a racemic dyad. These discrepancies areinterpreted as a result of various fine structures corresponding to grid search conformationsas well as thereby different interactions. The analysis on the most stable conformationsof PMAA confirmed that the ester groups are nearly perpendicular to the plane definedby the two adjacent skeletal bonds but may possibly change their relative orientations tomeet the requirement of lower energy during the conformational state transition. For eachpolyme, two global energy maps of a meso and a racemic dyad were finally constructedfrom the superposition of energy data for the three kinds of side-group orientations by theBoltzmann factors. From an ensemble average, the proposed scheme with three rotationalisomeric states (RIS) allowed us to access the experimentally unperturbed dimensions ofPAA chain via the configurational statistical mechanics. Although the calculation wasbased on the short-range, local interactions, it was interested to note that the experimentalcharacteristic ratios just fell within the range calculated for atactic chains.     

STUDIES ON THE TOTAL SYNTHESIS OF MAYTANSINOIDS (Ⅳ)——SYNTHESIS OF MAYTANSINE

This paper reports the total synthesis of optically pure maytansinol and maytansine. The physical constants and spectral data including R_f, m.p., specific rotation, HPLC, UV, CD, IR, NMR, and MS, of synthetic maytansinol and maytansine are identical with those of natural products in all respects. The preliminary biological test showed that synthetic maytansine possesses the same inhibitory activity in vitro against carcinoma cells as the natural product.     

STUDIES ON ULTRASONIC GRAFTING OF POLY(VINYL ACETATE) WITH POLY(ETHYLENE OXIDE)

The ultrasonic degradation of poly(ethylene oxide) and poly(vinyl acetate) in benzene solution, and grafting reaction of poly(vinyl acetate) with poly(ethylene oxide) were studied. It is found that the chain-scission reactions follow the course suggested by D. W. Ovenall. The structure of the copolymer was identified by IR, NMR and DTA, showing that the copolymer prepared is a graft copolymer mainly. The copolymer formed by irradiating 1% PEO/PVAc solution (PEO/PVAc:1/1 by weight) for a period of 10 rain at 18.2 kHZ, with 2.0 A input current on reversed main circuit, amounts to 10.5%.     

STUDIES ON THE PROPERTY OF SULFHYDRYL BINDING SITE ON THE LUNG NORMAL AND CANCER CELL MEMBRANE OF CHINESE HAMSTER WITH MALEIMIDE SPIN LABELS

In this paper, five maleimide spin labels with different chain lengths were used to studythe properties of binding sites of sulfhydryl groups on the meanbrane proteins of normal cellV_79 and cancer cells V_79-B_1 in the lung of Chinese hamster. The ratio of the strongly immobi-lized component to the weakly immobilized eomponent (s/w) and the rotational correlation time(τ_e) were calculated on the basis of ESR spectra. From the varying of the s/w and τ_c withthe ehain lengths of spilt labels it was deducted that the binding sites of sulfhydrylgroups on V_79 and V_79-B_1 membrane proteins were of eonical shape and that the binding sitesof sulfhydryl groups on V_79 membrane protein were deeper and narrower than those on V_79-B_1.     

PRELIMINARY STUDIES ON THE SYNTHESIS AND CHARACTERIZATION OF OXY-AND THIO-DIACETIC ACID HYDRAZITION AND THEIR FIRST-ROW TRANSITION METAL COMPLEXES

It has been made certain that thio-and oxy-diacetic acid hydrazidesare potential anticancer compounds.However,their ability to formcomplexes with transition metals and the properties of the complexes thusformed have not been studied.Employing a new potential anticancer ligand1,2-bis(thioacetic acid hydrazide)ethane prepared in our lab,along withligands oxydiacetic hydrazide and 1,2-bis(oxyacetic acid hydrazide)ethane,a series of 11 new first-row transition metal(M=Zn~(2+),Cu~(2+),Co~(2+),Ni~(2+))complexes with each of the above three ligands have been synthesizedand characterized by means of elemental analyses,IR,TG and X-raypowder diffraction.     

STRUCTURAL STUDIES ON NEW TYPES OF MACROCYCLIC COMPOUNDS I. CRYSTAL STRUCTURE OF NICKEL(II) COMPLEX WITH 5,5,7,12,12,14-HEXAMETHYL- 1,4,8,11-TETRAAZACYCLOTETRADECANE-N,N" -DIACETIC ACID

<正> Introduction. In recent years, studies on new types of macrocycles featuring ionizable functions have greatly increased since the ligands have an excellent ability to bind certain cations selectively. DOTA (1,4,7,10-tetraaza-cyclododecane-N,N',N", N'"-tetraacetic acid), for instance, forms the most stable complexes so far with calcium and trivalent lanthanides 1—5. It is     

STUDIES ON THE SYNTHESIS OF(±)-CEMBRENE-A

A precursor 2 of cembrene-A(a termite trail pheromone)was prepared fromgeraniol through 7 steps.     

ADSORPTION OF SAMARIUM(III) ON DIGLYCOLAMIDIC ACID RESIN

1.INTRODUCTIONThesynthesis,characterizationandsorptionpropertyofpolymericmaterialshavebeenstudiedbytheauthorsandotherresearchersinrecentyears[1~9].Diglycolamidicacidresin(DAAR)isanovelpolymericmaterialwhichcontainsafunctionalgroup[-N(CH2COOH)2].Itnotonlypossessesprotonthatcanexchangewithcation,butalsooxygenatomsthatcancoordinatedirectlywithmetalions.SoDAARcanbewidelyusedinthesorptionofmetalions.Inthisarticle,thesorptionpropertiesofDAARforSm(III)wereinvestigated.Somebasicsorption…