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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 structure of iron(III) 1,3-propanediaminetetraacetate (1,3-pdta) in aqueous solutions was studied on the basis of Raman spectroscopy, nuclear magnetic relaxation, and pH titration. It has been found that, in aqueous solution, Fe(1,3-pdta)− exists in a normal sexidentate hexacoordinate geometry. The six-membered chelate ring formed by the diamine moiety of the 1,3-pdta ligand does not adopt a skew-boat conformation having C2 symmetry (as found in sodium salt crystals) hut a twist-boat one having no C2 symmetry (as in the lithium salt crystals). Although edta complexes of iron(III) form a dimeric complex in slightly alkaline solutions, the 1,3-pdta complex of Fe(III) does not show such a tendency. The 1,3-pdta complex is stable only in the pH region of 2–7.5; the corresponding edta complex is stable even in a strongly acidic solution.

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

Magnetic Properties of Polymers Containing Tetraphenyl-porphinatosilver(II) as Their Side Chains

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

Copper(II) terephthalate absorbs a large amount of gases such as N2, Ar, O2, and Xe. The maximum amounts of absorption of gases were 1.8, 1.9, 2.2, and 0.9 mole per one mole of the copper(II) salt for N2, Ar, O2, and Xe, respectively, indicating that the gases were not adsorbed on the surface but occluded within the solid. The porous structure of copper(II) terephthalate, in which the gas is occluded, is deduced from the temperature dependence of magnetic susceptibilities and the linear structure of terephthalate.

Spin-lattice relaxation times of proton and fluorine nuclei in solid CHF3 were measured by the pulsed magnetic resonance technique between 7 and 116K. In 1H resonance, non-exponential recovery of magnetization was clearly observed. T1 data as well as magnetization recoveries were interpreted in terms of intramolecular magnetic dipole interactions between like spins and also between unlike spins, which are modulated by the isotropic reorientation of a whole molecule. A calculation of the temperature dependence of T1 was made by using an activation energy of 17kJ mol−1 and a pre-exponential factor of 1.0×10−16 s for the motion, yielding results in agreement with the present experimental results.

NQR frequencies and spin-lattice relaxation times ( T 1 ) have been measured from 4.2 to 262 K by the pulse method. The quadrupole coupling constant (4.795 MHz) and the asymmetry parameter (0.4964) at 4.2 K are compared with those in tetramethylpyrazine. The temperature dependence of T 1 shows peculiar behavior: Above 200 K, the fluctuation of the electric field gradient dominates the relaxation, and the activation energy ( E a ) of the molecular motion has a value of 55 ±5 kJ mol -1 . Below 100 K, T 1 is governed by dipolar interactions between 14 N and 1 H. T 1 minima are observed at 69 K and at 52 K. The methyl-group reorientation ( E a =6.5 kJ mol -1 ) contributes to T 1 (min) at 69 K, giving the pre-exponential factor of the correlation time, τ 0 =5 ×10 -13 s. T 1 (min) at 52 K is explained with the use of a tentative model of the level crossing between NQR and tunnel systems.

Cobalt(II), cobalt(III), nickel(II), and copper(II) complexes with N-(2-furylmethyl)salicylideneaminates (abbreviated as X–sal–fum) were synthesized. In addition to the M (X–sal–fum)2 type complexes, those of the formula Cu (X–sal–fum) Cl were obtained in crystals. The complexes Co (X–sal–fum)3 are six-coordinate, octahedral. The cobalt(II) complex is four-coordinate, tetrahedral and the nickel(II) complexes are four-coordinate, planar. In these complexes, the ligands X–sal–fum function as bidentates, the furan oxygen atom not being bound to the metal ions. The results are compared with those reported previously for related ligands. It is most likely that the complexes Cu(X–sal–fum)Cl consist of binuclear complexes with spin-spin interaction between copper(II)ions.

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.

Polyacrylate having tetraphenylporphinatocupper(II) and tetraphenylporphinatovanadyl(II) in its side chains (Cu : V = 1 : 1.2) has been prepared by the radical copolymerization of the corresponding acrylates. The temperature dependence of its magnetic susceptibility indicates the existence of ferromagnetic interaction.

The influence of electron exchange on the physical properties of polymers containing nitroxyl radical in their side chains has been studied by ESR, magnetic susceptibility measurement and cyclic voltammetry. ESR study shows that the electron exchange interaction between free radicals bound to a polymer chain is more effective than that between the corresponding monomeric radicals. Magnetic susceptibility (XM) was measured at temperatures between 4K and 273 K. The values of XM for the polymers obey the Curie-Weise Law (XM=c/(T−θ)), where magnetic moments obtained from XM show the presence of antiferromagnetic interaction between the nitroxyls of a polymer chain, although the interaction is not large enough to bring about long range ordering in the spin orientation of the nitroxyls. In the corresponding monomers, no antiferromagnetic interaction was observed. Cyclic voltammetry in DMF shows that the electrode process in polymer system is a reversible multiple-electron transfer reaction, where the number of the transfer (np) is 60% of the total free radicals per molecule. A comparison of the shape of the voltammetric response curve in the polymers with that in the corresponding monomers suggests that the interaction between nitroxyl radicals in the polymer is too weak to be reflected in electrochemical behavior.

Heat capacities of synthetic atacamite, Cu 2 Cl(OH) 3 , were measured in an adiabatic calorimeter between 4 and 300 K with particular attention to the relaxation phenomenon below 8 K. A suspected spin glass behavior was observed, which was compatible with previous measurements of the magnetic susceptibility.

Synthesis and Physicochemical Properties of Polyacrylates and Polymethacrylates with Tetraphenylporphinatocopper(II) and -vanadyl(II)

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.

ギ酸銅四水和物Cu(HCO2)2・4H20の結晶水を尿素でおきかえたCu(HCO2)2・(NH2CONH2)2・2H20とCu(HCO2)2・(NH2,CONH2)を合成した。酢酸銅の尿素付加物もえられた(2種類)。それらの磁化率をGouyの方法で測定して,銅原子の磁気モ_メントを求めた。Cu(HCO2)2・(NH2CONH2)2・2H20の磁気モーメントは1.67ボーア磁子,Cu(HCOa)2・(NH2CONH2)のモ_メントは1.08B・M・である。酢酸銅の尿素付加物は,酢酸銅一水和物のモーメントとほとんど同じ値のモーメントを示す。ギ酸銅は,四水和物の結晶水のうち2分子が尿素2分子と入れかわっても,四水和物の構造を維持するが,4分子の結晶水全部が尿素1分子でおきかわると,酢酸銅一水和物型の二量体構造をとる。酢酸銅は,どの尿素付加物も一水和物型のこ量体構造を保持する。尿素は,ギ酸銅とも,酢酸銅とも,共通な付加形式の,大気申で安定な,二量体構造の付加物をつくる牲質をもっている。

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.

Comparaison de la susceptibilite magnetique du polymere (obtenu par polymerisation dans le THF a 0°C du diphenyl-1,5 (p-methacryloyloxymethylphenyl)-3 verdazyl), en presence de butyllithium avec celle du monomere

The diamagnetic susceptibility per gram of iodine in solutions of various solvents was measured with a Gouy magnetic balance at room temperature. The value −0.363×10−6 in hexane solution was practically identical with that of iodine in pure phase. The values of diamagnetism of iodine in carbon disulfide, benzene, toluene, ethyl alcohol, and acetone ranging from −0.329 to −0.341 are only slightly smaller than the value in hexane, in disagreement with the data found in literatures. A qualitative support for the present writers’ result was afforded by theoretical considerations based on Mulliken’s theory of complexes formed in accordance with the mechanism of electron transfer from a donor molecule to an acceptor.

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

Resonance frequencies and spin–lattice relaxation times (T1) of nitrogen-14 nuclei in solid tetramethylpyrazine from liquid-helium temperature to room temperature have been measured by the pulse method and the temperature dependence of the quadrupole resonance frequencies is compared with those in the low-temperature phase of pyrazine. Below 150 K, the relaxation times are governed by the reorientation of the methyl groups. The activation energy and the pre-exponential factor of the correlation time are found to be Ea= 6.0 kJ mol–1 and τ0= 2 × 10–13 s, respectively. Above 150 K the relaxation times depend on torsional lattice vibrations and are determined by the indirect two-phonon processes so that T–11∝T2.