摘要:

The13C nmr spectra of α, αα, and αα′ substitutedtrans-fusedbicyclo [4,n,0]alkan-3 ones, are described. Substituent effects are discussed in terms of their electron withdrawing character, axial or equatorial configuration, and cyclohexane deformation.13C=O chemical shifts are shown to be based on the polarization of π bond and on C=O/X non-bonded interactions. As in ir and uv spectroscopy,13C nmr is a convenient method for detecting an a substituent configuration in fixed ring ketones.

ISSN:0008-4042    

DOI:10.1139/v80-238

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The relative viscosities and densities of glycine in 5%, 10%, 15%, and 20% w/w acetonitrile–water mixtures at 25, 30, 35, and 40 °C and ofDL-alanine in water, 5%, 15%, and 20% w/w acetonitrile water mixtures at 30 and 40 °C have been determined. The viscosityBcoefficients have been found to increase with increase in concentration of acetonitrile and also with the increase of temperature in both cases.The limiting apparent molar volumes and limiting value of effective flow volumes have also been calculated.

ISSN:0008-4042    

DOI:10.1139/v80-239

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The original treatment of unimolecular reactions given by Polanyi and Wigner in 1928 is recast in quantum terms. It is found that very simple and natural choices for the oscillation which is assumed to cause reaction lead to good predictions of the specific reaction rate constantk(E), and also the overall rate of reaction: nitrous oxide, carbon dioxide, methyl isocyanide, trideuteriomethyl isocyanide, ethyl isocyanide, ethyl chloride, cyclopropane, cyclobutane, and ethane are treated as illustrations.

ISSN:0008-4042    

DOI:10.1139/v80-240

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The effect of NaCl, KCl, RbCl, KBr, and KI on the temperature corresponding to the sound velocity maximum (TSVM) of aqueoust-butanol has been studied. The structural contribution to the shift in the TSVM of aqueoust-butanol by the addition of alkali halides was found to be in the order NaCl > KCl > RbCl and KCl > KBr > KI, thereby indicating that Na+ > K+ > Rb+and Cl− > Br− > I−in disrupting the hydrogen-bonded structure of water. The results also indicate an enhancement in the structure-breaking characteristic of both cations and anions in the presence oft-butanol. However, the order is the reverse of that found for pure water, i.e. Rb+ > K+ > Na+and I− > Br− > Cl−. The results have been explained on the basis of hydrophobic–hydrophilic interactions prevalent in the ternary Systems.

ISSN:0008-4042    

DOI:10.1139/v80-241

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The lyotropic liquid crystals formed by optically active detergents, water, and electrolyte have been investigated near and above the water-rich limit of the lamellar mesophase by using nuclear magnetic resonance, relative density observations, and polarized microscopy. The racemic mixture of α-alanine decyl ester forms a lamellar phase, a disc-micelle type II phase (which may co-exist in equilibrium), followed by an isotropic material as the water content increases. The resolveddorldetergent also forms a lamellar mesophase which may coexist with a type II disc-micelle system; however, as water content increases a transition occurs to a cholesteric lyotropic mesophase which itself passes over to an isotropic phase at the highest water contents studied. The range of existence, as a function of water content, for these intermediate type II DM and cholesteric phases is very narrow. The screw axis of the cholesteric mesophase aligns parallel to the magnetic field. A tentative structure of the cholesteric phase based on disc micelles distorted into a partial helix is suggested.

ISSN:0008-4042    

DOI:10.1139/v80-242

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Host bilayers of the large disc shaped micelles in type II DM phases have been prepared with two detergents having a 16 carbon chain. Studies of small quantifies of 10 carbon guest amphiphiles have been made using deuterium magnetic resonance. The host bilayer solution is only slightly perturbed by changes in simple counter and co-ions. The only major change in host chain order profiles is obtained when its pyridinium head groups are changed forN-trimethyl head groups. The guest chain motions near the non-polar chain terminus are considerably more restricted than in bilayers prepared from hosts of shorter chain length conforming closely to the guest chain length. The small changes observed in motion behaviour of the chains as a function of simple counter and co-ions can be a standard to test the effect of specific complexing agents on guest chain motions in the present System.

ISSN:0008-4042    

DOI:10.1139/v80-243

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Type II DM mesophases with disc-shaped micelles have been synthesized from decylammonium chloride and sodium decylsulphate – decanol amphiphiles with added water and electrolyte. Small amounts of guest amphiphiles have been added in the form of lauric acid or laurate ion. Specific and perdeuterated amphiphiles have been prepared and included in small quantifies in the mesophases. The deuterium magnetic resonance spectra of the magnetically aligned phases has been studied and quadrupole splitting doublets assigned to all segments of both host and guest hydrocarbon chains. The mesophases have been diluted with water over the stable range of type II DM behaviour at 34 ± 0.2 °C.The quadrupole splittings of all hydrocarbon chain segments, which reflect the degrees of order along C—D bonds in these segments, are accurately reproduced at all water contents by a knowledge of one quadrupole splitting in the chain and a simple proportionality constant which is derived for each segment of the chain. This further extends the previous results for host chains to those of guest chains studied here. The absolute degrees of order of chain segments are greatly influenced by water content because motion of the constituent disc micelles depends on the volume of interstitial water and they also vary in size as water is added. The packing in the bilayer solution of the disc micelles of the amphiphiles is therefore not a function of the interstitial water content in so far as the detailedtrans/gauchemotions of the hydrocarbon chains are not affected by changes in water content.The lauric acid-d23chain in the decylammonium chloride bilayer has the same degree of order along the D—D axis and the C—D bond, confirming that the motion of the pseudo rigid chain in the bilayer is cylindrically symmetric. The degree of order profiles of hosts and guests are all quite distinct indicating that chemical identity of the head group and its anchoring in the interface is the main determinant of the motion profiles.

ISSN:0008-4042    

DOI:10.1139/v80-244

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Zinc and cadmium anthranilates do not extract into non-polar solvents alone in the pH range 4.5–6.5. But their extraction is synergistically enhanced in presence of N bases, apparently by displacement of coordinated water. The synergistic effect varies with the bases in the order β-picoline > pyridine > quinoline. The values of extraction constants suggest that cadmium forms more stable complexes than zinc.

ISSN:0008-4042    

DOI:10.1139/v80-245

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Specific conductivities of ZnCl2–LiCl liquid mixtures have been determined in the 320–450 °C temperature interval and in the 0–0.54 LiCl mole fraction interval. They were found to increase steadily with both temperature and LiCl mole fraction, which was shown to be related to an increasing ionic character of the melt.

ISSN:0008-4042    

DOI:10.1139/v80-246

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

A series of copper(II) complexes of the title ligand are reported which exhibit both five-coordinate trigonal bipyramidal and pseudo-octahedral stereochemistries. Mixed stereochemistry complexes [Cu(NTBT)X]2[CuX4] (X = Cl, Br), [Cu(NTBT)Br]2[Cu2Br6]•CH3CN, and the complexes,, contain trigonal bipyramidal cations while six-coordinate structures are implicated in the Systems [Cu(NTBT)Br2]•H2O and [Cu(NTBT)(H2O)2•MeOH•H2O. The molecular structure ofhas been determined by single crystal X-ray diffractometry. The crystal is monoclinic and belongs to the space groupC2/cwithZ = 8,a = 24.254(3),b = 14.107(2),c = 16.329(2) Å and β = 105.94(1)°. The complex adopts a distorted trigonal bipyramidal structure (no axial symmetry) with the ligand coordinating in a 'tripod' fashion as an N4donor. The fifth ligand is a monodentate nitrate. The mean Cu—N distance is 2.07(3) Å and the Cu—O distance is 1.938(3) Å. A second nitrate oxygen atom is close to the copper centre (Cu—O distance 2.783(4) Å) and may represent a weakly bound sixth ligand. Both infrared and electronic spectral data support the presence of a sixth ligand.

ISSN:0008-4042    

DOI:10.1139/v80-247

出版商:NRC Research Press    

年代:1980

数据来源: NRC