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Chum salmon eggs were immersed in thyroxine, in thiourea, in halide salts, and in adrenalin on the day of fertilization and were maintained in these solutions until several months after hatching. All treatments affected growth either favourably or adversely, but only thyroxine and chloride changed body proportions. The changes due to chloride were significantly smaller than those following thyroxine treatment, and it is postulated that they are not “thyroxine-like” in nature. Thiourea inhibited colloid function with the usual hypertrophy and hyperplasia of the gland. Chloride and bromide depressed the heart rate significantly, whilst the other treatments had no effect. Iodide and bromide dispersed melanin pigment but thyroxine concentrated it slightly and adrenalin maximally so that adrenalin treated live fish were very pale. Thyroxine increased markedly the deposition of guanine and must, therefore, accelerate the hydrolysis of nuclear purines. It is concluded that specific effects produced by thyroxine in developing chum salmon are not duplicated by the halides and adrenalin. / Science, Faculty of / Zoology, Department of / Graduate

The object of this work was to produce and identify reaction intermediates in systems containing group I and group II halides treated with fluorine. The systems which are studied in detail are the NaCl and KCl/F₂ and SrCl₂/F₂ systems. In accordance with predictions from kinetic studies, ESR has shown that treatment of vacuum-sublimed NaCl with F₂ at room temperature produces a defect containing an unpaired electron, and that the decay of this defect is retarded by Cl₂. The ESR spectrum indicates an anisotropic g-factor and unresolved hyperfine structure. In KCl, a spectrum is obtained which is closely similar except that the hyperfine structure is partly resolved. The spectra appear consistent with interactions of the unpaired electron with Cl atoms, rather than with F or such impurities as 0 or Br, and can be accounted for adequately by a model of the defect as linear Cl[formula omitted], i.e., an H center or something very similar. For NaCl, the spectra indicate that the vacuum-sublimed material is sometimes partly oriented. It is suggested that centers with one-electron deficiency are observable at such high temperatures in vacuum-sublimed material because this consists of essentially perfect crystals devoid of sites which could accept a second electron from the centers. The reaction of SrCL₂ powder or single crystal with fluorine at room temperature produces a defect, stable after removal of fluorine but located close to the reaction interface only, which has an electron spin resonance absorption. The ESR spectrum is consistent with a model of the defect as a chlorine atom displaced from an anion site towards a neighbouring anion vacancy. The principal directions of the hyperfine tensor and g-tensor are two two-fold axes and a four-fold axis of the SrCl₂ lattice. The tensor components indicate that the unpaired electron is localized on the Cl atom, and suggests that the atom is subject to a strong crystal field determind chiefly by two nearest-neighbour cations which define a two-fold axis of the crystal. The unpaired electron is in an orbital mainly of p-character and aligned along a two-fold axis which is probably the one perpendicular to the line of the cations. The single-crystal spectrum, although haying orientation-dependent line positions, has line shapes and intensities resembling those of a powder spectrum. This suggests a range of relative displacement of Cl atoms and neighbouring cations along a "reaction co-ordinate" which is probably a four-fold axis of the crystal. / Science, Faculty of / Chemistry, Department of / Graduate

Using both infrared and Raman techniques the vibrational spectra of selected polymorphs of the ammonium halides; NH₄C1, ND₄C1, NH₄Br, ND₄Br, NH₄I and ND₄I, have been recorded in the spectral region 4000 - 50 cm⁻¹. The Raman spectra of NH₄F and ND₄F were also recorded. Although all the foregoing crystals have been the subject of previous spectroscopic investigations some important new features are observed. These include (i) Raman active longitudinal modes and (ii) previously unreported internal and external modes. In addition more meaningful assignments are made for some previously reported spectral lines. Included are assignments involving (i) the non-degenerate NH₄⁺ stretching mode in combination with acoustical modes and (ii) the transverse and longitudinal components of the triply degenerate NH₄⁺ bending mode in combination with the librational mode. A study analagous to that involving the ammonium halides was made of the following alkali-metal borohydrides: LiBH₄, LiBD₄, NaBH₄> NaBD₄, KBH₄, KBD₄, RbBH₄ and CsBH₄. From the vibrational spectrum of potassium borohydride recorded at 10°K it is possible to infer that the ordered phase associated with this salt has a cubic structure compatible with the 2 space group Td² . The vibrational spectrum of the ordered tetragonal phase of sodium borohydride allows the placing of the seven BH₄⁻ (D₂d) internal vibrational modes. In addition a mode of translatory origin is observed and a mode of rotatory origin is inferred from a line assigned as the second overtone of a librational mode. In the case of lithium borohydride seven of the nine BH₄⁻ (C₅) modes are observed. Six modes of translatory origin appear in the infrared and a mode of rotatory origin is inferred from a line assigned as the second overtone of a librational mode. The structure of potassium borohydride at room temperature is discussed and evidence in support of a structure intermediate between the ordered cubic Td² phase and the disordered cubic 0h⁵ phase of sodium borohydride is given. Finally, the F matrix associated with an undistorted XY₄ (Td) (XY₄ = NH₄⁺, BH₄⁻) ion and the G matrix associated with the same ion which has undergone a slight angular distortion to give an XY₄(D₂d) ion is used to calculate the contribution of the kinetic energy to the spectrum of the XY₄ ( D₂d) ion. It is found that the order of appearance in the spectrum of the B₂ and E components associated with the two F₂ vibrations is correctly predicted. / Science, Faculty of / Chemistry, Department of / Graduate

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The bis 1,4,7-trithiacyclononane (1,4,7-TTCN) complexes of iron, cobalt, nickel and copper are reported in this work. Their properties have been examined using computer-controlled electrochemical and spectroscopic techniques. These TTCN complexes form readily, are unusually symmetrical and support electron transfer reactions at the metal center. The cobalt(II) complex is octahedral, low spin and symmetrical. Four oxidation states of cobalt-TTCN complex are observed; two one-electron transfer processes are reversible. Copper (II) bis 1,4,7-TTCN is unusually symmetrical evidenced by both solid phase and ambient temperature aqueous phase electron paramagnetic resonance spectra. An unusually high redox potential for the copper complex indicates extraordinary stability of the Cu(I) oxidation state but evidently not at the expense of Cu(II) stability. The complex also has a high formation constant compared to other copper-thioether complexes. This unusual strength of thioether donor is attributed to ligand geometry. The 1,4,7-TTCN molecule is the only known cyclic polythioether to have all sulfur atoms endodentate. This structure contributes to thermodynamic stability of complexes as the ground state configuration of the free ligand is maintained in the complex.