摘要:

The photolysis of C2H5F at 147 nm was studied at room temperature. The principal products include C2H3F, C2H2, C2H4, CH4, and C2H6. The principal primary photochemical reactions involve the molecular elimination of HF and H2, and, to a lesser extent, C—F and C—C bond fission. The effect of reactant and added inert gas pressure on the product yields has been investigated and it was found that the stabilization/decomposition ratio, C2H4/C2H2, displays opposite pressure dependence with ethyl fluoride and argon. This result is interpreted in terms of the higher energy transfer efficiency of the C2H5F molecule.

ISSN:0008-4042    

DOI:10.1139/v72-229

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The electrochemical reduction of silver ions at the surface of a model phospholipid membrane proceeds without the application of an electric field. The silver deposition is dependent on I−and I2. The charge transfer complexes formed by iodine with phospholipids and cholesterol are the most probable donors for the electron transfer reaction. Cholesterol membranes do not show the silver deposition unless an external electrical field is applied. An account for the difference is given on the basis of dissimilar ion distribution profiles within phospholipid and cholesterol membranes.

ISSN:0008-4042    

DOI:10.1139/v72-230

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The infrared absorption of single crystals of anhydrous strontium formate has been measured in the region 4000 to 500 cm−1. The internal fundamentals of two sets of crystallographically non-equivalent types of formate ions are identified. Frequencies of external fundamentals are tentatively inferred from absorption bands appearing in the second order spectrum. Measurement of laser excited Raman spectra in the region 700–10 cm−1has yielded assignments for all of the expected translational modes. None of the librational modes were observed.

ISSN:0008-4042    

DOI:10.1139/v72-231

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The kinetics of the copper(II) catalyzed decarboxylation of 3-oxo-glutaric acid have been investigated in unbuffered solutions at 25 °C and 0.60 Mionic strength, both in the presence of aromatic tertiary amines, and with hydrated copper ions alone. The amines used were 2,2′-bipyridyl and 1,10-phenanthroline. Equilibrium constants for the formation of the various copper complexes were determined with a copper ion selective electrode, particularly for the species CuAB, where A is the 3-oxo-glutarate ion, and B is an aromatic amine. The kinetic behavior was then interpreted as arising from the simultaneous decarboxylation of all the species present containing a 3-oxo-glutarate ligand. The resulting rate constants indicated that some kinetic effect was transmitted through the copper from the base to the 3-oxo-glutarate, but the effect was relatively small, and the bulk of the catalytic effect caused by the base arose from changes in equilibrium concentrations.

ISSN:0008-4042    

DOI:10.1139/v72-232

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

An expression for the magnetic susceptibility of octahedral d1complexes is derived exactly in terms of an orbital reduction factorktaking into account the presence of the formal2Eexcited state. Sample calculations show that the improved expression gives results for susceptibility which are lower at times by several percent from those given by previous expressions. The results given by Figgis using Kotani's method are adequately precise when the spin–orbit coupling constant is no larger than ~0.1Dq.

ISSN:0008-4042    

DOI:10.1139/v72-233

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The two percarbonates KHCO4and K2C2O6were prepared by chemical or electrolytic methods in order to measure their infrared and Raman spectra. The permonocarbonate is unstable and very hygroscopic. Theanion forms quite strong intermolecular hydrogen bonds, although somewhat less so than the bicarbonate anion. As for theanion, the rather small number of its infrared and Raman bands suggests a planar and centrosymmetric configuration. In both percarbonates the O—O vibration shows nearly the same frequency as in H2O2, presumably due to coupling with neighboring vibrations. For comparison purposes the peroxyhydrate K2CO3.3H2O2was studied likewise.

ISSN:0008-4042    

DOI:10.1139/v72-234

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The bark ofNaucleadiderrichii(Rubiaceae) has afforded a considerable number of constituents, mainly alkaloids. For convenience these have been placed in four categories: (1) simple β-carbolines, (2) simple pyridines, (3) indole-pyridines, and (4) miscellaneous substances. Isolation procedures and the elucidation of the structures of constituents in categories (1) and (2) are described in this paper. Spectroscopic evidence supported by synthesis has been used to assign structures1,2,3, and4to the four simple β-carbolines and structures5,6,7, and8to the four simple pyridines isolated.

ISSN:0008-4042    

DOI:10.1139/v72-235

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Six alkaloids isolated from the bark ofNaucleadiderrichiihave been shown to have structures that contain both indole and pyridine units. Because of the small amounts available of each constituent, investigation of structure has been confined mainly to the application of spectroscopic techniques; these have shown that all of these alkaloids belong to the novel indole-pyridine class, and have led us to propose structures or part structures with varying degrees of confidence for each of the alkaloids. Structure1was deduced for naucledine, C18H15N3O2, and confirmed by synthesis. Its spectroscopic characteristics indicate that nauclederine, C19H19N3O2, has structure3, but this has not yet been confirmed by synthesis. Evidence is presented that nauclechine, C21H21N3O3, has part structures6and7, and it is suggested that these can be incorporated in structure8. A working hypothesis for the structure of nauclexine, C18H17N3O2, is represented by9. Two alkaloids, ND-363C, C21H21N3O3, and ND-305B, C19H19N3O, are closely related, the latter being formally derived from the former by removal of a carbomethoxy group; each appears to exist as an equilibratible pair of isomers containing an indolic (substituted β-carboline) and a pyridine part linked together in a manner which may incorporate a spiro carbinolamine ether (as in12) that can form ring-opened or solvated derivatives in some solvents.

ISSN:0008-4042    

DOI:10.1139/v72-236

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Basic substances isolated from the bark ofNaucleadiderrichiiand not placed in one of the three earlier alkaloidal categories include an alkaloid, C21H26N2O4, designated ND-370, and an amorphous material that appears to be an alkaloidal glycoside. Also isolated were the non-basic substances benzamide and antiarol (3,4,5-trimethoxyphenol), and two monoterpenoids given the names naucleol and naucledal; the spectroscopic characteristics of naucleol, C9H14O3, can be accounted for by structure1a, and those of naucledal, C10H12O4, by structure2a, but the data do not establish the structures unequivocally. The structural relationships between the various constituents isolated from this plant and their possible biogenetic implications are discussed.

ISSN:0008-4042    

DOI:10.1139/v72-237

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The AlH2Cl hydrogenolysis of ether solutions of 2-alkoxytetrahydrofurans in which the alkoxy group is either CH3O, C2H5O,i-C3H7O, ort-C4H9O, gives only those products resulting from ring C—O bond cleavage. However, substituents at C-5 of 2-methoxytetrahydrofuran exert a strong effect on the ratio of ring toexoC—O bond cleavage. Thus, alkyl (electron donor) groups at C-5 promote an increase in the amount ofexocleavage, the proportion increasing from 62.5 to 100% as the C-5 alkyl group is changed from CH3tot-C4H9. In contrast, electron withdrawing substituents, CH3OCH2— and C6H5, at C-5 favor ring cleavage to the extent of 93 and 84% respectively.The results are interpreted in terms of the influence that these substituents exert through their electronic properties on the relative ease of attainment of the transition state leading to either ring C—O orexoC—O bond cleavage. However, evidence is provided to show that the bulk steric effect of these substituents also controls, though to a minor extent, the proportion of ring toexocleavage.

ISSN:0008-4042    

DOI:10.1139/v72-238

出版商:NRC Research Press    

年代:1972

数据来源: NRC