The reaction of platinum(II) chloride with neat benzonitrile gave bis(benzonitrile)dichloroplatinum(II) as a mixture of cis and trans isomers in variable proportions, depending on the temperature. The geometry of the chromatographically separated isomers was identified on the basis of the dipole-moment and IR data. The 13C NMR spectra in CDCl3 also enabled us to discriminate between isomers in both chemical shift and coupling to the 195Pt of the cyanide carbon, the resonance peak of which was utilized to follow the isomerization. The rate constant (kc) for the cis-to-trans isomerization was found to be (3.8±0.3)×10−6 s−1 in CDCl3 at 25 °C, ten times larger than that [kt=(2.9±0.2)×10−7 s−1] of the reverse reaction. The equilibrium between cis and trans strongly favored trans in CDCl3 at 25 °C, whereas in benzonitrile the cis form was the dominant species at room temperature, while the trans form was dominant at higher temperatures.

Enthalpies of mixing of some α,ω-alkanediol monoalkyl ether(ADAE)+heptane systems were measured at 298 K, and limiting partial molar excess enthalpies of ADAE at infinite dilution, x→0lim  HE⁄x(1−x), were estimated. The ADAE used were CH3O(CH2)nOH (n=2, 3, 4), C2H5O(CH2)nOH (n=2, 3), C3H7O(CH2)nOH (n=2, 3), and C4H9O(CH2)2OH. The values of x→0lim  HE⁄x(1−x), obtained were compared with those of normal alcohols, and discussed in the light of the intramolecular hydrogen bond contained in ADAE. The enthalpic contribution due to the intramolecular hydrogen bond in ADAE is estimated to be about 10 kJ mol−1.

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The electric dipole moments of diphenyl sulfide, sulfoxide, and sulfone and their derivatives were determined in benzene solutions at 25°C. The observed moments are used to estimate the mesomeric moments on the assumption of the vector addition of group moments. The mesomeric moments of the phenylmercapto, phenylsulfinyl, and phenylsulfonyl groups are estimated to be −0.12, 0.10, and 0.44 D, respectively. The steric effect of ortho-substituents is also discussed on the basis of the dipole moment data.