摘要:

A series of polyacene quinone radical polymers were made. The chemical analysis showed that the severe reaction conditions favored the Scholl (elimination of H2and H2O) over the Friedel–Crafts reaction. Electron paramagnetic resonance spectra confirmed the presence of a biradical. Conductivity measurements in the ohmic and space charge limited regions showed that large π systems existed and that carrier traps were shallow. The π system structure and absence of quinone structure was confirmed by ir spectrometry which also showed the optical absorption edge to be 0.8 eV. Charge was injected into the polymers forming electrets and thermally stimulated current emission spectra confirmed a shallow trap depth (∼0.4 eV). It is postulated that thermal excitation to a triplet state produces the biradical and conduction is by hopping between adjacent π systems and charge storage is associated with the extensive π systems.

ISSN:0008-4042    

DOI:10.1139/v76-262

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Heats of dilution of aqueous solutions of two polymethacrylic acid samples having a viscosity average molecular weight of 5000 (PMA-I) and 140 000 (PMA-II) respectively and of isobutyric acid (BA) have been measured at 25 °C using a Tian–Calvet microcalorimeter. The same measurements have been repeated in presence of HCl (0.2 N). Aqueous solutions of sodium and rubidium salts of PMA-I and II have also been investigated. Dilution of BA solutions is endothermic at high solute concentration and then becomes exothermic as concentration decreases and the presence of HCl does not affect the results. Dilution of PMA solutions is exothermic over the investigated concentration range in agreement with the results of Eliassaf and co-workers. PMA-I gives a more exothermic heat of dilution than PMA-II in the lower concentration range. The presence of HCl does not affect appreciably the results for PMA-II but it makes the dilution of PMA-I solutions less exothermic. The results are discussed in the light of Liquoriet al.'s model for PMA chain which may adopt a globular or an extended solvated coil depending on solvent properties. Heats of dilution of aqueous solutions of sodium salts of both samples I and II are endothermic over the entire concentration range investigated whereas the heats of dilution of rubidium salts are exothermic.

ISSN:0008-4042    

DOI:10.1139/v76-263

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The dimeric iridium(III) hydride complexes [IrHCl(SAr′)(PAr3)2]2where Ar = 4-CH3C6H4or C6H5and Ar′ = 4-CH3C6H4, 4-CH3OC6H4, 4-FC6H4, or C6H5have been shown to react in halogenated solvents such as chloroform or 1,2-dichloroethane to form triply bridged dimeric hydrated complexes of the type, [H(Ar3P)2Ir(SAr′)2ClIr(PAr3)H]Cl•2H2O. When PAr3 = (4-FC6H4)3P, no triple bridge formation was observed. However, the dimeric complexes, [IrHCl(SAr′)(PAr3)2]2including PAr3 = (4-FC6H4)3P all react with AgClO4in acetone to form the complexes, [H(Ar3P)2Ir(SAr′)2ClIr(PAr3)2H]ClO4•x(CH3)2CO (x = 0–3). The isolation and characterization of these triply bridged dimeric iridium(III) hydrides are discussed.

ISSN:0008-4042    

DOI:10.1139/v76-264

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

An effective internuclear potential for the hydrogen molecule is deduced from the experimental energy levels; this potential is valid in the sense that it reproduces the rotation–vibration energy levels to an accuracy of the order of ±0.1 cm−1, and is unique in the sense that it is equally accurate for all observed values of the rotational quantum numberJ.The implied corrections to the adiabatic relativistic internuclear potential are consistent with the estimated values for the non-adiabatic coupling correction over the whole range of internuclear separation.

ISSN:0008-4042    

DOI:10.1139/v76-265

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The electronic spectra of three diazafluoren-9-one isomers have been measured in cyclohexane solution and the results compared with those of 'molecules in molecules'(MIM) and PPP calculations. A satisfactory agreement between experimental and theoretical data has been found, and five π → π* transitions can be assigned to their uv spectra. For two compounds dipole moments in benzene solution have been measured and results are compared with theoretical values obtained by MIM and CNDO/2 calculations.

ISSN:0008-4042    

DOI:10.1139/v76-266

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Complexes of the types [CosalenPR3]X, [Cosalen(PR3)2]X, [Co(DH)2PPh3X], and [Co(DH)2(PR3)2]ClO4, many of them new, have been prepared and characterized with respect to1H nmr spectra, ligand field parameters, and equilibrium constants for the formation of the 2:1 salen complexes.1H chemical shifts appear to be dominated by anisotropic rather than inductive effects, while the relative tertiary phosphine ligand field strengths appear to correlate with the steric requirements of the phosphines as well as their expected σ donor strengths. Ease of formation of the 2:1 salen complexes is determined largely by steric effects, as aretranseffects in the DH systems.

ISSN:0008-4042    

DOI:10.1139/v76-267

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The system InBr3–NaBr–H2O shows the existence of the following solid phases at 25 °C: InBr3(anhyd.), NaBr(anhyd.), and NaBr.2H2O. A hydrated form of indium tribromide does not exist at 25 °C

ISSN:0008-4042    

DOI:10.1139/v76-268

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The decomposition of dimethylbenzylanilinium chloride (DMBAC) was found to follow second-order kinetics in ethanol or aqueous ethanol solvents, but first-order kinetics in higher alcoholic solvents. From the activation parameters obtained at 80 °C, different isokinetic relationships were found for the ethanol series and the higher alcohol series. The dissociation constants of DMBAC in ethanol and isopropanol at 80 °C were calculated to be 7.34 × 10−3and 2.10 × 10−4 mol/l, respectively, from conductivity measurements. Accordingly, it was concluded that in higher alcohols the major part of DMBAC exists as ion pairs, which are responsible for the decomposition reaction, but in ethanol the decomposition involves a bimolecular reaction between free ions.

ISSN:0008-4042    

DOI:10.1139/v76-269

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Eight samples of ferric phosphates have been prepared at different pHvalues under different conditions. This material shows cation exchange properties. Ferric phosphate prepared by ferric nitrate and ammonium dihydrogen phosphate at pH 1 is the most stable and shows the maximum ion exchange capacity, hence, this sample is studied in detail. The mole ratio of Fe3+:PO43−is 1:2. The ion exchange capacity depends upon temperature and hydrated radii, and these relations are discussed. Certain important separations are achieved on the ferric phosphate column. Its oxidation properties are also qualitatively investigated with some reducing agents.

ISSN:0008-4042    

DOI:10.1139/v76-270

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Acid dissociation constants for the compounds1–6in water–DMSO and methanol–DMSO of varying composition have been determined by a potentiometric method. In all solvents the equatorial group ionized more easily, by gain or loss of a proton, than the axial group, but in the more aqueous solvents the presence of atert-butyl group across the cyclohexane ring inhibited this ionization slightly. An explanation based on displacement of solvent molecules from the outer solvation sphere is advanced.

ISSN:0008-4042    

DOI:10.1139/v76-271

出版商:NRC Research Press    

年代:1976

数据来源: NRC