Other observations

Adamson, A.W. and Fleischauer, P.D., 1975. Concepts of Inorganic Photochemistry. Wiley-Interscience, New York, N.Y., 439 pp. 

and Takabatake, E., 1973. Photochemical formation of methylmercuric compounds from mercuric acetate. Chemosphere, 3 131—133. 

and Landymore, A.F., 1974. Physiological and ecological significance of the chemical instability of uric acid and related purines in sea water and marine algal culture medium. J. Fish. Res. Board Can., 31 1327—1335. 

Organic films on natural waters Their retrieval, identification, and modes of elimination. J. Geophys. Res., 77 5062—5075. 

Balzani, V. and Carassiti, V., 1970. Photochemistry of Coordination Compounds. Academic Press, New York, N.Y., 400 pp. 

When an external, symmetry breaking field is applied perpendicular to the director of a nematic liquid crystal, confined between two orienting surfaces, the lowest order fluctuation mode undergoes a softening and 

Mansfield, P. LoPresti, Dynamics of picosecond laser-induced density, temperature, and flow-reorientation effects in the mesophases of liquid crystals, J. Appl. Phys. 1991, 29, 2972-2976. 

P Zhou, Y. Liang, H. Li, Dynamics of transient probe beam amplification via coherent multiwave mixing in a local nonlinear medium-nematic liquid crystal, IEEE J. Quantum Electron 1993, 29, 2972-2976. 

DrevenSek, M. CopiC, Properties of nematics studied by four wave mixing. Mol. Cryst. Liq. Cryst. 1991, 207, 241-250. 

Kresse, Dielectric behaviour of liquid crystals, Fortschr. Phys. 1992, 30, 507-582. 

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Decades of work have led to a profusion of LEERs for a variety of reactions, for both equilibrium constants and reaction rates. LEERs were also established for other observations such as spectral data. Furthermore, various different scales of substituent constants have been proposed to model these different chemical systems. Attempts were then made to come up with a few fundamental substituent constants, such as those for the inductive, resonance, steric, or field effects. These fundamental constants have then to be combined linearly to different extents to model the various real-world systems. However, for each chemical system investigated, it had to be established which effects are operative and with which weighting factors the frmdamental constants would have to be combined. Much of this work has been summarized in two books and has also been outlined in a more recent review [9-11]. 

The pyrolysis thresholds of this series of compounds show that the thiazole structure is thermostable, decomposition temperatures being generally between 450 and 510°C. Other observations that can be made are ... 

Catalytic hydrogenation of 1 4 dimethylcyclopentene yields a mixture of two products Iden tify them One of them is formed in much greater amounts than the other (observed ratio =10 1) Which one is the major product" ... 

Groundwater monitoring is a necessary component in any investigation of subsurface contamination. A wide variety of information can be gleaned from the data including groundwater velocity and direction, and contaminant identification and concentration. These data can be combined with other observations to infer various characteristics of the contamination. Examples are source and timing of the release, and future location of the contaminant plume. 

The abihty to enlarge tiny objects to macroscopic dimensions immediately suggests the need to make measurements and other observations helptiil in documenting what is seen and thus enabling others to confirm that a specimen has been identified with certainty. Many physical and chemical properties of a microscopic substance can be measured, even on particles nearing atomic dimensions. 

There are other equations for other illuminants and other observers (3) and also various modifications for special conditions (31). 

Constitution. When coniine is distilled with zinc dust or heated with silver acetate/ a new base, coiiyrine, CgH N, differing from coniine by six atoms of hydrogen, is formed. This on oxidation yields pyridine-2-carboxylic acid and, since it is not identical with 2-isopropylpyridine, must be 2-propylpyridine (I). When coniine is heated with hydriodic acid at 300° it yields w-octane (II). These and other observations due mainly to A. W. Hofmann, made it clear by 1885 that coniine was probably a-propylpiperidine (III), and this has been amply confirmed by other reactions of the alkaloid and by syntheses. Thus, Wolffenstein showed that on oxidation with hydrogen peroxide, coniine is converted into amino-w-propylvaleraldehyde (IV) ... 

Constitution. On oxidation with chromic acid, conhydrine yields Z-piperidyl-2-earboxylic acid. It is converted into Z-coniine either by reduction of the iodo-derivative (iodoconiine), C,HijNI, formed by the action of hydriodic acid and phosphorus at 180° or by hydrogenation of the mixture of coniceines produced, when it is dehydrated by phosphorus pentoxide in toluene. These and other observations indicate that the p- ygen atom must occur as a hydroxyl group, in the w-propyl side-chain in either the a- (XV) or (XVI) position, since the y-position would involve... 

There are also on record a number of other observations regarding S. American plants believed to be associated with this drug, e.g., Freise has given preliminary descriptions of alkaloids isolated from the following species —... 

Various other observations of Krapcho and Bothner-By are accommodated by the radical-anion reduction mechanism. Thus, the position of the initial equilibrium [Eq. (3g)] would be expected to be determined by the reduction potential of the metal and the oxidation potential of the aromatic compound. In spite of small differences in their reduction potentials, lithium, sodium, potassium and calcium afford sufficiently high concentrations of the radical-anion so that all four metals can effect Birch reductions. The few compounds for which comparative data are available are reduced in nearly identical yields by the four metals. However, lithium ion can coordinate strongly with the radical-anion, unlike sodium and potassium ions, and consequently equilibrium (3g) for lithium is shifted considerably... 

The reaction of quinolinium and isoquinolinium salts with dialkyl cadmium has been observed to be slow and occurs in relatively poor yield. The structures of the products are the same as those obtained from reactior with Grignard reagents and the yields ranged from 0-20% (40). Leadini references to other observed reactions of quinolinium and isoquinoliniuir salts with Grignard reagents can be found in the above cited review (31). 

By dehydrating guaiol, the sesquiterpene alcohol present in guaiac wood oil, Wallach and Tuttle obtained a bicyclic sesquiterpene which they called guaiene. It has been obtained by different methods by other observers from guaiol, and its characters are recorded as follows... 

Each observer Oi (1) knows that m-1 other observers exist, but does not know anything about their internal construction (or predicate skeletons ) (2) must balance two complementary desires - (i) the desire to create as unambiguous a language as possible to communicate as easily as possible with all other observers (which requires his world-viev. to be as similar to the world-views of other observers as possible) (ii) the desire to be as distinct - and therefore, as locally well-defined... 

The preferential conversion of the aluminum enolatc 2 c to diastereomer 3 is consistent with the boat-like transition state A where the enolate has adopted the usual antiperiplanar E geome-try42-50. The aldehyde substituent occupies the lower energy equatorial position of a boat-like transition state which places the bulky dialkylaluminum moiety away from the iron ligands. Possible transition states for the other observed diastereomeric products are also illustrated. 

Postulate 2 is the statement that a possible motion to one observer must also appear possible to any other observer. 

Pai Vemeker and Kannan [1273] observe that data for the decomposition of BaN6 single crystals fit the Avrami—Erofe ev equation [eqn. (6), n = 3] for 0.05 < a < 0.90. Arrhenius plots (393—463 K) showed a discontinuous rise in E value from 96 to 154 kJ mole-1 at a temperature that varied with type and concentration of dopant present Na+ and CO2-impurities increased the transition temperature and sensitized the rate, whereas Al3+ caused the opposite effects. It is concluded, on the basis of these and other observations, that the rate-determining step in BaN6 decomposition is diffusion of Ba2+ interstitial ions rather than a process involving electron transfer. 

Such a model should be as simple as possible, without however missing any of the underlying thermodynamic and physicochemical factors which cause electrochemical promotion. In particular it will be shown that even the use of Langmuir-type adsorption isotherms, appropriately modified due to the application of potential (or equivalently by the presense of promoters) suffice to describe all the experimentally observed rules G1 to G7 as well as practically all other observations regarding electrochemical promotion including the effect of potential on heats of adsorption as well as on kinetics and reaction orders. 

From this observation of the inhibition by adenosine, and other observations, Newell and Tucker suspected the existence of a common synthetic pathway for adenosine and thiamine, and proved (with the help of a collection of mutants) that the bifurcation occurred after the 5-amino- l-(P-D-ribofura-nosyl)imidazole 5 -phosphate (46) step (Scheme 23). Finally, they found that 5-amino-l-(0-D-ribofuranosyl)imidazole (47), labeled with l4C in the imidazole ring, was incorporated into pyramine without significant loss of molar radioactivity by a mutant that is able to use this nucleoside (presumably after phosphorylation).53,54... 

For the reason given above and for other reasons, it is unlikely that the encounter complex is a n complex, but just what kind of attraction exists between Y+ and ArH is not known, other than the presumption that they are together within a solvent cage (see also p. 694). There is evidence (from isomerizations occurring in the alkyl group, as well as other observations) that n complexes are present on the pathway from substrate to arenium ion in the gas-phase protonation of alkylbenzenes. ... 

This is called the SrnI mechanism," and many other examples are known (see 13-3, 13-4,13-6,13-12). The lUPAC designation is T+Dn+An." Note that the last step of the mechanism produces ArT radical ions, so the process is a chain mechanism (see p. 895)." An electron donor is required to initiate the reaction. In the case above it was solvated electrons from KNH2 in NH3. Evidence was that the addition of potassium metal (a good producer of solvated electrons in ammonia) completely suppressed the cine substitution. Further evidence for the SrnI mechanism was that addition of radical scavengers (which would suppress a free-radical mechanism) led to 8 9 ratios much closer to 1.46 1. Numerous other observations of SrnI mechanisms that were stimulated by solvated electrons and inhibited by radical scavengers have also been recorded." Further evidence for the SrnI mechanism in the case above was that some 1,2,4-trimethylbenzene was found among the products. This could easily be formed by abstraction by Ar- of Ft from the solvent NH3. Besides initiation by solvated electrons," " SrnI reactions have been initiated photochemically," electrochemically," and even thermally." ... 

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