Solubilities of the cyclodextrins in the presence of transition metal salts

The solubilities of -, -, and -cyclodextrin have been measured in the presence of the first row transition metals: Cr³⁺, Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺; chlorides, nitrates and sulphates (in this case Fe²⁺), and, for companson, with CaCl₂, the corresponding Group IIa salt. Where possible the measurements are reported as a function of the activity of the salts. In general, for the transition metals the sulphates all show a linear decrease in solubility with increasing salt activity: for the nitrates the solubility increases and then reaches a limiting value; and for the chlorides a small decrease in solubility is observed at low activity followed by an increase in solubility at higher salt activity. Circular dichroism measurements confirm that there is no direct complexation at non-basic pH.Presented at the Sixth International Seminar on Inclusion Compounds, Istanbul, Turkey, 27–31 August 1995.     

Quantitative determination of selected compounds in a Kentucky 1R4F reference cigarette smoke by multidimensional gas chromatography and selected ion monitoring-mass spectrometry

Eight compounds from a Kentucky 1R4F reference cigarette smoke condensate have been determined by selected ion monitoring-mass spectrometry (SIM-MS) to confirm the validity of multidimensional gas chromatography (MDGC) as a quantitative tool in complex mixture analyses. Four electrostatically precipitated smoke condensate samples of 100 cigarettes each are dissolved individually in 25 mL of 2-propanol. The 2-propanol contains two methyl esters (C8 and C14) and seven deuterium-labeled compounds used as internal standards (IS). Analysis of the compounds of interest, pyridine; acetamide; acrylamide; phenol; o-, m-, and p-cresol; and quinoline, is accomplished by using two heartcuts. Heartcut times of the MDGC analysis are selected such that at least one IS is transferred with each group of compounds being analyzed. This study shows that the MDGC technique previously developed and described can be used for quantitative analyses. A comparison is made between the two types of internal standards. The results obtained for both types of internal standards agree within 20% of each other, on the average, with higher standard deviations for approximately 60% of the compounds where methyl esters are used as internal standards.     

New organolithium addition methodology to diversely functionalized indoles

A novel synthetic approach to diversely functionalized indoles is described. Boc-protected ortho-aminostyrenes undergo an alkyllithium addition reaction, thereby generating a lithiated intermediate, which upon reaction with specific electrophiles sets up a cascade reaction process between the reacted electrophile and ortho-amino substituent, facilitating an in situ ring closure, followed by dehydration, to generate an indole ring system. This methodology is demonstrated by the synthesis of a range of 3,5-, 1,3,5-, and 2,3,5-substituted indoles.     

Synthesis of a new bidentate ferrocenyl N-heterocyclic carbene ligand precursor and the palladium (II) complex trans-[PdCl2(CfcC)], where (CfcC) = 1,1′-di-tert-butyl-3,3′-(1,1′-dimethyleneferrocenyl)-diimidazol-2-ylidene

A new ferrocenyl-N-heterocyclic carbene ligand precursor 1,1′-bis[(1-tert-butylimidazolium)-3-methyl]ferrocene dichloride has been synthesised and structurally characterised. The imidazolium salt was readily deprotonated in situ with KN(SiMe₃)₂ and reacted with [PdCl₂ (cod)] to afford the structurally characterised palladium (II) complex trans-[PdCl₂(C^∧fc^∧C)], where (cod) = 1,5-cyclooctadiene and (C^∧fc^∧C) = 1,1′-di-tert-butyl-3,3′-(1,1′-dimethyleneferrocenyl)-diimidazol-2-ylidene.     

Spectral properties and ring conformation of some novel 2,3-dihydro-1H-1,4-diazepinium cations

A series of 2,3-dihydro-1H-1,4-diazepinium salts, which includes fused ring systems of known ring-junction configuration, has been prepared. A study of the spectral properties indicates that this ring system is largely planar and is sufficiently flexible to permit cis and trans fusion at the 2,3-bond to 5- or 6-membered rings without significant distortion.     

A comparison of the cellulolytic activities of rumen bacteria and protozoa

Cellulolytic activity can be released from rumen Entodiniomorphid protozoa by gentle sonication (Coleman, 1978) and there is evidence that most of this activity is of protozoal rather than bacterial origin (Coleman, 1978). Cellulolytic activity can also be released under the same conditions from a crude mixture of bacteria isolated from the rumen. The purpose of this communication is to compare the cellulolytic activity in fractions (prepared by sonication followed by centrifugation (15,500g, 30 min) to produce a clear, bacteria-free supernatant fluid) from faunated and defaunated sheep. Activities were measured by the release of reducing material from carboxymethylcellulose and the release of dye from cellulose azure (Sigma, type II), but unfortunately with both methods the relationship between product and time or enzyme concentration was a curve with a steadily decreasing slope. To overcome this difficulty a standard curve of product against concentration of an extract of the ciliateEpidinium ecaudatum caudatum was constructed for all experiments. Using this curve, the amount of product formed with other enzyme preparations was converted into concentrations of this extract. The specific activity (activity/mg protein) of this extract was taken to be 100. Fractions were prepared from strained rumen contents by differential centrifugation and after sonication and centrifugation as described above, no activity was found in the 360g min pellet (“protozoal fraction”) from defaunated sheep or in the green or brown layer that was present above the protozoa in the same fraction from refaunated animals. Cellulolytic activity was progressively released from washed rumen bacteria prepared from both types of sheep during sonication for 15 min, at which time the specific activity of the material was 2–3% of that in the protozoon. There was a small but variable amount of activity (specific activity, 0.1–1.0%) in the cell-free rumen liquor. If it is assumed that the activity released from the protozoa and bacteria is actually available to degrade cellulose, an estimate can be made of the comparative importance of protozoa and bacteria in rumen cellulolysis. In a sheep containing 20,000 epidinia/mL as the only ciliate protozoon, the bacteria and cellfree rumen liquor contained only 12 and 2 1/2%, respectively, of the activity in the protozoa. If 65% of the protozoa die and are degraded in the rumen (Leng, 1982), then the protozoal cellulase released could be very important in cellulose degradation.     

Quantum hair and quantum gravity

A black hole may carry quantum numbers that arenot associated with massless gauge fields, contrary to the spirit of the no-hair theorems. The quantum hair is invisible in the classical limit, but measurable via quantum interference experiments. Quantum hair alters the temperature of the radiation emitted by a black hole. It also induces non-zero expectation values for fields outside the event horizon; these expectation values are non-perturbative in , and decay exponentially far from the hole. The existence of quantum hair demonstrates that a black hole can have an intricate quantum-mechanical structure that is completely missed by standard semiclassical theory.Based on an essay which received second award from the Gravity Research Foundation, 1991