Charge transfer complexes were studied spectrophotometrically in the liquid state by a modified Benesi-Hildabrand method. TiCl_4 - Benzene and TiCl_4 - diphenyl ether solutions were found to form contact charge transfer complexes, that is complexes with very weak and non-directional interactions. The systems TiCl_4 - anisole and TiCl_4 - diethyl ether form complexes of the types AD and AD_2 where A stands for TiCl_4 and D stand s for the organic donor. The formation constants for the complexes were, for the TiCl_4 - anisole, K_1 = 0.077, K_2 = 0.01; and TiCl_4 - diethyl ether, K_1= 3.0, K_2 = 1.0. The system TiCl_4 - tetrahydrofuran was also examined and found to form a complex whose formation constant is 0.58. An infrared spectrophotometric study was made of the contact charge transfer complexes TiCl_4 - diphenyl ether and TiCl_4 - p-xylene, and there was no evidence of any band due to the complex itself. However, the TiCl_4 - ether complexes were studied by infrared in the liquid state for the ethers p-dioxane, dimethyl ether, diethyl ether, tetrahydrofuran, and anisole, and absorption maxima were present which were due to the complexes. It was concluded that AD and AD_2 complexes exist in each of these systems. It was also concluded that the bonding in each case was from the oxygen of the ether to the titanium of the TiCl_4 , and that the Ti was dsp^3 hybridized for the DA complexes and d^2sp^3 for the D_2A complexes. An x-ray study was made of the solid 1:1 TiCl_4 - anisole complex. The crystal was found to be orthorhombic with parameters a = 19.426, b = 17.098 and c = 6.744 Å. The space group was found to be Cmcm. The density of the solid was 1.7. From this it was concluded that there were eight molecules per unit cell. The most reasonable way the eight molecules could be arranged in the unit cell consistent with the symmetry requirements is with the oxygen bonded to the titanium. A heat of mixing calorimeter was constructed in which the heats of mixing of volatile liquids could be measured. The calorimeter was a two piece metal container whose top and bottom compartments were separated by aluminum foil. The calorimeter had internal vanes which increased heat conduction and aided the solenoid actuated plunger-stirrer. The calorimeter was equipped with a poly ethylene diaphragm so that, when pressure loaded, there was no vapor phase and near constant pressure was maintained. The heat capacity of the calorimeter and its contents were determined with every run and used in the calculation of the heat of mixing of that run. The heat of mixing of the system N,N-dimethylacetamide - CCl_4 was measured as a function of mole fraction CCl_4 (x). The data can be expressed to within 1% of the maximum value by the equation Δ H_M = x(1-x)[- 590.8+294.7(2x-1)+89.5(2x-1)^2+187.5(2x-1)^3+264(2x-1)^4)
College and Department
Chemistry and Biochemistry
BYU ScholarsArchive Citation
Jensen, Reed J., "Thermodynamics of charge transfer complexes" (1965). Theses and Dissertations. 8243.