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The temperature dependence of 35Cl NQR frequencies in bis(4-chlorophenyl)sulfone was measured in the temperature range of 4.2-297 K. Below 115 K four NQR lines due to four inequivalent chlorines exist in the commensurate phase, contrary to the single NQR line reported by Corbero et al. It follows that the commensurate-incommensurate transition is of the first-order, and the incommensurate-normal transition at 150 K is quasi-continuous. It is also suggested that the successive phase transitions are triggered by the small angle rotation of the molecules about their C2-axes.

The temperature dependence of the magnetic susceptibilities for 4-methacryloyloxy- and 4-acryloyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl (MOTMP and AOTMP, respectively) was measured. Intermolecular magnetic coupling in these radicals was changed from antiferromagnetic to ferromagnetic by substituting hydrogen at α-position with a methyl group. A magnetic phase transition for MOTMP was observed at 0.14 K in the measurement of the temperature dependence of heat capacity. The circumstantial evidences support that the ordered state is of ferromagnet.

The temperature dependence of 35C1, 81Br, and 127I NQR frequencies and 1Hspin-lattice relaxation times (T1) for CH3NH3PbX3 (X = Cl, Br, I) was measured through the successive phase transitions in these solids. The isotropic reorientation of the CH3NH3 ions takes place in the higher-temperature phases (tetragonal [I4/mcm] and cubic) of the three salts (Ea= 11 kJ mol -1). T1's in the lowest-temperature phases (orthorhombic) indicate that the cations undergo correlated C3-reorientation in the chloride (Ea = 5.45 kJ mol -1)and in the iodide (Ea = 5.80 kJ mol -1, whereas correlated (Ea = 2.40 kJ mol-1) and uncorrected (Ea = 7.50 kJ mol-1) C3- reorientations are excited in the bromide. It is also revealed that the rotational tunneling of the cations governs T1 at lowtemperature region in the orthorhombic phases of these salts

The magnetic properties of polymers containing tetraphenylporphin-Cu(II) (TPP-Cu(II)) or tetraphenylporphin-Ag(II) (TPP-Ag(II)) in the side chains were studied by the magnetic susceptibility (χM) measurement (4—300 K) and ESR spectroscopy. The values of χM for the polymer containing TPP-Cu(II) were found to obey the Curie–Weiss law, and a magnetic moment showed the occurrence of a weak antiferromagnetic interaction between Cu(II) ions. The values of χM for the polymer containing TPP-Ag(II) did not obey any simple equation such as the Curie–Weiss law or Bleaney–Bowers equation and simulation of temperature dependence of χM showed the presence of strongly interacting sites. This strong interaction may possibly arise from a hyperexchange interaction through C = O groups situated among the Ag(II) ions. An ESR study also supported the presence of this interaction between the side groups in a polymer chain.

14 N NQR frequencies and T 1 's were measured between 54 and 150 K in crystalline trans -azobenzene which has two different molecular sites, orientationally ordered and disordered, at room temperature. The NQR parameters at 77 K were determined to be e 2 Q q / h =5.0150 MHz and η=0.4231 for the ordered site, and e 2 Q q / h =4.9619 MHz and η=0.4060 for the disordered site. The fine structure of each resonance line was observed by the Fourier transform method. It changes abruptly around 90 K, indicating the existence of a phase transition. The fine structures and their change at the phase transition can neither be attributed to the intramolecular dipole interaction between the two nitrogen nuclei, nor to crystallographic inequivalency of the molecules in the unit cell.

Polyacrylates containing tetraphenylporphinatocobalt(II) (TPP-Co(II)) and chloro(tetraphenylporphinato)iron(III) (TPP-Fe(III)Cl) as side chains were prepared. Their physicochemical properties were investigated by UV-visible spectroscopy, ESR spectroscopy, and magnetic susceptibility (χM) measurement. In comparison of the visible spectra of polymers with those of the corresponding monomers, hypochromism of the Soret band and some of Q bands was observed in both polymers. In the measurements of ESR spectra, hyperfine splitting constants and anisotropic g-values of TPP-Co(II) or -Fe(III)Cl moieties bound to the polymers were somewhat different from those of TPP-Co(II) and -Fe(III)Cl, respectively. These differences in spectroscopic behavior suggest that there are some interactions between porphinatometal ion moieties in the polymers. The values of χM for the polymers containing TPP-Co(II) were found to obey the Curie–Weiss law with θ=190 K, which was explained in terms not only of spin-orbit interaction of t...

New basic copper(II) formates Cu 3 (HCOO) 2 (OH) 4 and Cu(HCOO)(OH) have been prepared and characterized by the magnetic susceptibility and PMR spectrum. The magnetic susceptibility of Cu 3 (HCOO) 2 (OH) 4 can be explained by the theoretical equation for linear trinuclear clusters. Cu(HCOO)(OH) shows a phase transition to an antiferromagnetic ordered state accompanied by a spin-flop phenomenon at 21.3 K. Each compound exhibits PMR spectrum consisting of two components each showing the Fermi contact shift. The coupling constants are determined as A CH = 1.8 G and A OH = −1.2 G for Cu 3 (HCOO) 2 (OH) 4 and as A CH = 3.9 G and A OH = −2.0 G for Cu(HCOO)(OH): the oxygen atoms in the hydroxy groups of each compound carry positive spin density and the carbon atoms of the formate groups negative spin density. The sign and magnitude of the spin exchange interaction depend markedly on the mechanism of spin delocalization onto the ligand molecules.

On the basis of infrared spectroscopy and X-ray powder patterns, it is shown that 5-chlorosalicylalsalicylamine and its copper(II) salt are different from salicylal-5-chlorosalicylamine and its copper(II) salt, respectively, in the crystalline state. The nuclear magnetic resonance studies on salicylalsalicylamine and related compounds in solutions show that the double bond in the –CH=N–CH2- portion of these molecules is localized, i. e., the prototropic rearrangement of hydrogen atoms does not take place. Therefore, salicylalsalicylamine-copper(II) presents an example of a new type of three-coordinated copper (II) complexes showing a subnormal magnetic moment in spite of having ligands of a three-dimensional structure. This provides an additional evidence in favor of a presumption made by the present writers on the structure of three-coordinated copper(II) complexes showing a normal magnetic moment.

The magnetic susceptibility of an aqueous solution of erythrocruorin from an ark-shell known as Anadara inflata (Reeve) was measured by a Gouy magnetic balance at 15°C in deoxygenated and in oxygenated state. On the plausible assumption that oxygenated erythrocruorin contains no unpaired electrons, the magnetic moment per one iron atom of this respiratory pigment in deoxygenated state was calculated to be equal to 4.96 Bohr magnetons. This corresponds closely to the presence of four unpaired electrons per heme and to almost complete quenching of orbital moments. For this reason, the erythrocruorin bears a remarkable resemblance to hemoglobins of vertebrates in so far as its magnetic properties are concerned.

In this paper, we report the synthesis, spectral and magnetic properties, and X-ray crystal structure of the unique mononuclear iron(III) complexe