Effects of In-Hospital Exercise on Frailty in Patients with Hepatocellular Carcinoma.

Frailty including physical inactivity is associated with the survival of patients with hepatocellular carcinoma (HCC). We aimed to investigate the effects of in-hospital exercise on frailty in patients with HCC. This was a multi-center observational study. Patients with HCC were classified into exercise (n = 114) and non-exercise (n = 67) groups. The exercise group was treated with a mixture of aerobic and resistance exercises (20-40 min/day, median four days). Frailty was assessed using the liver frailty index (LFI). Factors for changes in LFI were examined by multivariate and decision-tree analyses. The factors were also examined after propensity score matching. During hospitalization, LFI was significantly improved in the exercise group compared to the non-exercise group (ΔLFI -0.17 vs. -0.02, p = 0.0119). In multivariate analysis, exercise (odds ratio (OR) 2.38, 95% confidence interval (CI) 1.240-4.570, p = 0.0091) and females (OR 2.09; 95%CI, 1.062-4.109; p = 0.0328) were identified as independent factors for the improvement of LFI. In the decision-tree analysis, exercise was identified as an initial classifier associated with the improvement of LFI. Similar findings were also seen in the propensity score matching analyses. We demonstrated that in-hospital exercise improved frailty in patients with HCC. Thus, in-hospital exercise may be beneficial for improving physical function in patients with HCC.

Slow walking speed overlapped with low handgrip strength in chronic liver disease patients with hepatocellular carcinoma.

AIM: Walking speed and grip strength are parameters of muscle function; however, evaluating walking speed is not always available in clinical practice. We aimed to investigate the impact of walking speed on the evaluation of muscle dysfunction in chronic liver disease (CLD) patients with hepatocellular carcinoma (HCC). METHODS: We enrolled 107 consecutive CLD patients with HCC in this study (age 76 years [range 60-92 years]; female/male 39/68; body mass index 22.9 [range 20.0-25.3]; chronic hepatitis/liver cirrhosis 25/82). Muscle dysfunction was evaluated using the Asian Working Group for Sarcopenia criteria (grip strength or walking speed) and the Japan Society of Hepatology criteria (grip strength). A correlation between walking speed and skeletal muscle index was evaluated. Independent factors for slow walking speed were evaluated using a logistic regression analysis. RESULTS: There was no significant correlation between walking speed and skeletal muscle index (r = 0.14, P = 0.16). For both the Asian Working Group for Sarcopenia and Japan Society of Hepatology criteria, 33.6% of all patients were classified as having muscle dysfunction. All patients with slow walking speed (4.7% of all patients) also showed low handgrip strength. The logistic regression analysis identified grip strength as an independent factor for slow walking speed (OR 0.65; 95% CI 0.432-0.838; P = 0.008). CONCLUSIONS: No difference was seen in the prevalence of muscle dysfunction between the Asian Working Group for Sarcopenia and Japan Society of Hepatology criteria in CLD patients with HCC. Furthermore, all patients with slow walking speed also showed low handgrip strength. Thus, for the evaluation of muscle dysfunction, grip strength might be a suitable proxy for walking speed in CLD patients with HCC.

Regioselective Photocyclizations of Di(quinolinyl)arylamines and Tri(quinolinyl)amine with Emission Color Changes and Photoreaction-Induced Self-Assemblies.

Bis[2,4-di(trifluoromethyl)quinoline-7-yl]amine (1), bis[2,4-di(trifluoromethyl)quinoline-7-yl]methylamine (2), bis[2,4-di(trifluoromethyl)quinoline-7-yl]phenylamine derivatives, Q2 NPhX; X=NO2 (3 a), I (3 b), H (3 c), OMe (3 d), and NH2 (3 e), tris[2,4-di(trifluoromethyl)quinoline-7-yl]amine (4), and bis[2,4-di(pentafluoroethyl)quinoline-7-yl]-4-nitrophenylamine (5) were prepared as functional fluorophores. On irradiating the solution samples, 1 showed no noticeable alteration, whereas 2, 3 a-d, and 4 showed emission color changes from yellowish green to blue, indicating that a photoreaction took place. Analyses of the photoproduct based on absorption and emission spectra, (1) H NMR spectra, and X-ray crystallography indicated that photocyclization reactions occurred regioselectively and quantitatively to form bent-bent dipyridocarbazoles. In 3 a-d, the reaction rates depended on the solvent polarity and the substituent on the benzene ring. The photoreactions were accelerated with decreasing solvent polarity and with increasing electron-withdrawing character of the substituents. The photocyclization of triquinolineamine 4 was faster than that of 3 a in all solvents. The results of semiempirical quantum-chemical PM6 calculations suggested that the observed regioselective photocyclization could be explained by stabilization of the excited triplet transition state for the bent-bent form because of the molecular geometry with the CH-NQ hydrogen bonds. The solution of 5 in MeOH displayed photoreaction-induced self-assembly behavior to form twisted tape-like fibers of width 200 nm, as determined by TEM imaging.

3- and 4-(α-diazobenzyl)pyridine-N-oxides as photoresponsive magnetic couplers for 2p-4f heterospin systems: formation of carbene-Tb(III) and carbene-Dy(III) single-molecule magnets.

3- and 4-(α-diazophenyl)pyridine-N-oxides, and , were prepared as new photoresponsive magnetic couplers in heterospin systems. Lanthanide dinuclear complexes, [Ln(III)(tta)3()]2; Ln(III) = Gd (), Tb (), and Dy () and tta = 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate, bridged with in µ2 coordination mode were obtained. The obtained , , and were isostructures. The isomeric complex, [Tb(III)(tta)3()]2 was also prepared. In the carbene-Ln(III) complexes [Ln(III)(tta)3( and )]2 generated by photolysis, regioselectively interacted with the Ln(III) ions through pyridine-N-oxide, in which the magnetic coupling of was weakly ferromagnetic, while that of was insignificant. Before and after irradiation of , no SMM behavior was observed. In contrast, the Tb(III) and Dy(III) complexes being anisotropic functioned as heterospin SMMs. Before irradiation, showed no SMM behavior. After irradiation, two species showing slow magnetic relaxations were produced and one of them exhibited SMM behavior with the thermal activation barrier, Ueff/kB = 30 K, and τ0 = 5.8 × 10(-8) s. In , SMM behaviors were observed before and after irradiation, and the Ueff/kB value of 102 K (τ0 = 3.6 × 10(-7) s) before irradiation was reduced to 39 K (τ0 = 1.5 × 10(-8) s) after irradiation.

One-, Two-, and Three-Dimensional Heterospin Complexes Consisting of 4-(N-tert-Butyloxylamino)pyridine (4NOpy), Dicyanamide Ion (DCA), and 3d Metal Ions: Crystal Structures and Magnetic Properties of [M(II)(4NOpy)x(DCA)y(CH3CN)z]n (M = Mn, Co, Ni, Cu, Zn).

Solutions of 3d metal ion salts, M(NO3)2, 4-(N-tert-butyloxylamino)pyridine (4NOpy), and dicyanamide (DCA) in CH3CN were mixed to afford single crystals of the polymeric complexes [M(II)(4NOpy)x(DCA)y(CH3CN)z]n (M(II) = Mn (1), Co (2), Ni (3), Cu (4a and 4b), Zn (5)). X-ray crystallography revealed that the crystal structures are a three-dimensional (3-D) network for 1, 2-D networks for 2, 3, 4a, and 5, and a 1-D chain for 4b. Crystals of 2, 3, 4a, and 5 contained CH3CN molecules as crystal solvents, which were readily desorbed in the ambient atmosphere. After desorption of the CH3CN molecules, the crystal structures of 2 and 3 were confirmed to be slightly shrunk without destruction of the crystal lattice. Crystals of 2, 3, 4a, and 5 after desorption of crystal solvents were used for investigations of the magnetic properties. Complex 1 showed antiferromagnetic interactions to form a ferrimagnetic chain and exhibited the magnetic behavior of a 2-D (or 3-D) spin-canted antiferromagnet with TN = 12 K. Complex 2 containing anisotropic Co(II) ions also showed the behavior of a 1-D (or 2-D) spin-canted antiferromagnet with TN = 6 K. In 3, 4a, and 4b, the aminoxyl of 4NOpy ferromagnetically interacted with the metal ion with coupling constants of JM-NO/kB = 45, 45, and 43 K, respectively. In 5, the magnetic couplings between the aminoxyls in 4NOpy through the diamagnetic Zn(II) ion were weakly antiferromagntic (JNO-NO = -1.2 K). DCA might be a weak antiferromagnetic connector for the metal chains.

Magnetic properties of 1:2 mixed cobalt(II) salicylaldehyde Schiff-base complexes with pyridine ligands carrying high-spin carbenes (Scar = 2/2, 4/2, 6/2, and 8/2) in dilute frozen solutions: role of organic spin in heterospin single-molecule magnets.

The 1:2 mixtures of Co(p-tolsal)2, p-tolsal = N-p-tolylsalicylideniminato, and diazo-pyridine ligands, DXpy; X = 1, 2, 3l, 3b, and 4, in MTHF solutions were irradiated at cryogenic temperature to form the corresponding 1:2 cobalt-carbene complexes Co(p-tolsal)2(CXpy)2, with Stotal = 5/2, 9/2, 13/2, 13/2, and 17/2, respectively. The resulting Co(p-tolsal)2(CXpy)2, X = 1, 2, 3l, 3b, and 4, showed magnetic behaviors characteristic of heterospin single-molecule magnets with effective activation barriers, Ueff/kB, of 40, 65, 73, 72, and 74 K, for reorientation of the magnetic moment and temperature-dependent hysteresis loops with a coercive force, Hc, of ∼0, 6.2, 10, 6.5, and 9.0 kOe at 1.9 K, respectively. The relaxation times, τQ, due to a quantum tunneling of magnetization (QTM) were estimated to be 1.6 s for Co(p-tolsal)2(C1py)2, ∼2.0 × 10(3) s for Co(p-tolsal)2(C2py)2, and >10(5) s for Co(p-tolsal)2(CXpy)2; X = 3b, 3l, and 4. In heterospin complexes, organic spins, carbenes interacted with the cobalt ion to suppress the QTM pathway, and the τQ value increased with increasing the Stotal values.

Polymorphic equilibrium responsive thermal and mechanical stimuli in light-emitting crystals of N-methylaminonaphthyridine.

Crystal polymorphs of 1,8-naphthyridine derivative, being anti and syn conformers, show a reversible transformation from anti to syn by heating and from syn to anti by grinding with the alteration of emittance intensity, and notably, thermal transformation from anti to syn conformer took place in single-crystal-to-single-crystal (SC-to-SC) form, which was confirmed by a single crystal X-ray crystallography.

Crystal structures and emitting properties of trifluoromethylaminoquinoline derivatives: thermal single-crystal-to-single-crystal transformation of polymorphic crystals that emit different colors.

2,4-Trifluoromethylquinoline (TFMAQ) derivatives that have amine (1), methylamine (2), phenylamine (3), and dimethylamine (4) substituents at the 7-position of the quinoline ring were prepared and crystallized. Six crystals including the crystal polymorphs of 2 (crystal GB and YG) and 3 (crystal B and G) were obtained and characterized by X-ray crystallography. In solution, TFMAQ derivatives emitted relatively strong fluorescence (lambda(max)(f)=418-469 nm and Φ(f)(s)=0.23-0.60) depending on the solvent polarity. From Lippert-Mataga plots, Δµ values in the range of 7.8-14 D were obtained. In the crystalline state, TFMAQ derivatives emitted at longer wavelengths (lambda(max)(f)=464-530 nm) with lower intensity (Φ(f)(c)=0.01-0.28) than those in n-hexane solution. The polymorphous crystals of 2 and 3 emitted different colors: 2, lambda(max)(f)=470 and 530 nm with Φ(f)(c)=0.04 and approximately 0.01 for crystal GB and YG, respectively; and 3, lambda(max)(f)=464 and 506 nm with Φ(f)(c)=0.28 and approximately 0.28 for crystal B and G, respectively. In both crystal polymorphs of 2 and 3, crystals GB and G showed emission color changes by heating/melting/cooling cycles that were representative. By following the color changes in heating at the temperature below the melting point with X-ray diffraction measurements and X-ray crystallography, the single-crystal-to-single-crystal transformations from crystal GB to YG for 2 and from crystal B to G for 3 were revealed.

Magnetic properties of 1 : 4 complexes of CoCl2 and pyridines carrying carbenes (S(0) = 4/2, 6/2, and 8/2) in diluted frozen solution; influence of carbene multiplicity on heterospin single-molecule magnets.

The microcrystalline sample of a parent complex, [CoCl(2)(py)(4)], showed a single-molecule magnet (SMM) behavior with an effective activation barrier, U(eff)/k(B), of 16 K for reversal of the magnetism in the presence of a dc field of 3 kOe. Pyridine ligands having 2-4 diazo moieties, DYpy; Y = 2, 3l, 3b, and 4, were prepared and confirmed to be quintet, septet, septet, and nonet in the ground state, respectively, after irradiation. The 1 : 4 complexes, CoCl(2)(DYpy)(4); Y = 2, 3l, 3b, and 4 in frozen solutions after irradiation showed the magnetic behaviors of SMMs with total spin multiplicity, S(total) = 17/2, 25/2, 25/2, and 33/2, respectively. Hysteresis loops depending on the temperature were observed and the values of coercive force, H(c), at 1.9 K were 12, 8.4, 11, and 8.1 kOe for CoCl(2)(CYpy)(4); Y = 2, 3l, 3b, and 4, respectively. In dynamic magnetic susceptibility experiments, ac magnetic susceptibility data obeyed the Arrhenius law to give U(eff)/k(B) values of 94, 92, 93, and 87 K for CoCl(2)(CYpy)(4); Y = 2, 3l, 3b, and 4, respectively, while the relaxation times for CoCl(2)(CYpy)(4); Y = 2 and 3l, obtained by dc magnetization decay in the range of 3.5-1.9 K slightly deviated downward from Arrhenius plots on cooling. The dynamic magnetic behaviors for CoCl(2)(CYpy)(4) including [CoCl(2)(py)(4)] and CoCl(2)(C1py)(4) suggested that the generated carbenes interacted with the cobalt ion to increase the relaxation time, τ(q), due to the spin quantum tunneling magnetization, which became larger with increasing S(total) of the complex.

Preparations, crystal structures, and magnetic properties of N,N-dipyridylaminoxyl as a new magnetic coupler and its one-dimensional cobalt(II) chains.

N,N-Dipyridilaminoxyl, NOpy(2), having a stable aminoxyl, was prepared as a new magnetic coupler for heterospin systems. Solutions of NOpy(2) were mixed with those of bis{1,1,1,5,5,5, hexafluoro-4-(phenylimino)-2-pentanonate}cobalt derivatives, Co(hfpip-X)(2), at a 1:1 ratio to afford the polymeric cobalt(II) complexes, [Co(hfpip-X)(2)(NOpy(2))](n); X = H (1), F (2), F(3) (3), F(5) (4), Cl (5), Cl(3) (6), Br (7), and I (8) as single crystals. In all complexes, the local structures of the cobalt-complex units were compressed octahedra and the pyridine ligands in NOpy(2) units coordinated to the cobalt ions in trans configuration to form linear chains for 1-4 and in cis configuration to form helical chains for 5-8. In the chains, the aminoxyl in NOpy(2) ferromagnetically interacted with the cobalt ions to produce the ferromagnetic chains with J(intra)/k(B) = 9-14 K. In the magnetic susceptibility experiments of aligned sample of 6, the magnetic easy axis was determined to be the a* axis, which was the direction perpendicular to the b axis of the chain axis. The resulting chains, all except 4, interacted antiferromagnetically among each other, and especially in 1, 5, 7, and 8, the magnetic behaviors characteristic to canted two-dimensional (2D) antiferromagnets with T(c) = 5.6, 4.0, 4.0, and 6.2 K, respectively, were observed. All complexes showed slow magnetic relaxations affected by the interchain antiferromagnetic interaction. The effective activation barriers, Δ(eff)/k(B), for the reorientation of the magnetism for all complexes except 4 were estimated to be 25-39 K in the presence of a direct current (dc) field.

Assemblies of functional small-sized molecules having 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl responsive to heat and pH in water and their water proton relaxivities.

1,3,5-Triureabenzene derivatives carrying alkyl (C(n)) and poly(ethylene glycol) (Eg(m)) chains C(n)Eg(3) (1, 2, and 3, n = 6, 7, and 8, respectively) and C(n)N(X)Eg(m) (4 and 5, X = M (methyl), n = 6 and 8, respectively, m = 3; 6 and 7, X = T (2,2,6,6-tetramethylpiperidine-1-oxyl, TEMPO), n = 6, m = 3 and 6, respectively) were prepared. All compounds in aqueous solutions exhibited the lower critical solution temperature (LCST) phenomena unique for small-sized molecules and formed self-assemblies above the transition temperature, T(t), of the LCST. Only compound 3 formed a hydrogel with a minimum gelation concentration of 0.5 mM (0.05 wt %). In 1.0 mM aqueous solution, the T(t) values were determined to be in the range of 12-40 °C. In addition, the T(t) values for 4-7 containing tertiary amine also responded to the solution pH with high sensitivity. The LCST behaviors for all compounds were reversible in the cycles of warming and cooling. The water proton relaxivities, r(1), for 6 and 7 carrying TEMPO were altered below and above T(t) and were largely reduced by the formation of self-assemblies above T(t). Compound 6 showed r(1) values at 25 °C of 0.92 and 0.23 mM(-1) s(-1) at pH 7.0 and 6.0, respectively. In transmission electron microscopy (TEM) images, globular particles with polydispersity were observed, and their average hydrodynamic diameters (D(H)) were determined to be in the range of 2400-730 nm by dynamic light scattering. In the TEM and scanning electron microscopy images of a xerogel sample of 3, bundles of fibers with a diameter of ca. 10 nm and a network structure, respectively, were observed.

Magnetic properties after irradiation of 1:4 complexes consisting of CoX2, X=NCS⁻, Cl⁻, and NCO⁻, and phenylpyridyldiazomethane in dilute frozen solutions: axial ligand effect in heterospin single-molecule magnets.

The solutions of 1:4 complexes of Co(X)(2)(D1py)(4), X = Cl(-), and NCO(-) and D1py = phenylpyridyldiazomethane, were photolyzed under cryogenic conditions, and their magnetic properties were investigated by direct current (DC) and alternating current (AC) magneto/susceptometries. After irradiation, the resulting cobalt-carbene complexes, Co(X)(2)(C1py)(4), exhibited the behaviors of heterospin single-molecule magnets (SMMs) strongly depending on the axial ligands. In Co(X)(2)(C1py)(4): X = Cl(-) and NCO(-), the effective activation barriers, U(eff), for the reorientation of the magnetic moment and the resonant quantum tunneling time, τ(Q), characteristic to SMM properties were estimated to be 91 and 130 K, and 4 × 10(3) and 2 × 10(5) s, respectively. The τ(Q) of Co(NCS)(2)(C1py)(4) with U(eff) = 89 K was found to be 6 × 10(2) s. In Co(X)(2)(C1py)(4): X = Cl(-) and NCO(-), temperature-dependent hysteresis loops were also observed below the blocking temperature (T(B) = 3.2 and 4.8 K, respectively) and the coercive forces, H(c), of 7.0 and 20 kOe at 1.9 K, respectively, were obtained. In a series of 1:4 complexes of Co(X)(2)(C1py)(4), X = NCS(-), Cl(-), and NCO(-), the axial ligands strongly affected the heterospin SMM properties, and the NCO(-) ion having the large magnitude of the ligand-field splitting in a spectrochemical series, gave the largest U(eff) and H(c) and the longest τ(Q).

Magnetic behaviors of heterospin chains consisting of cobalt(II) complexes and dipyridylcarbenes.

The 1:1 mixture of Co(Brhfpip)(2) and D1py(2) gave isomeric diazocobalt complexes, 1 and 2, formulated by [Co(Brhfpip)(2)(D1py(2))](n). Complexes 1 and 2 have zigzag and linear chain structures by the cis and trans coordination of pyridine units in D1py(2), respectively. After irradiation of microcrystalline samples, the generated carbene interacted with the cobalt ion to form ferromagnetic chains, 1c and 2c. Those isomeric chains exhibited slow magnetic relaxation with U(eff) = 93 and 87 K and H(c) = 20 and 13 kOe at 1.9 K for 1c and 2c, respectively.

Evaluation of mobility of 2-N-tert-butylaminoxyladenosine incorporated into oligodeoxynucleotides.

We synthesized oligodeoxynucleotide (ODN, 3) containing 2-N-tert-butylaminoxyladenosine (1) and studied EPR spectra of 3 and its duplexes. The h(+)/h(0) values in the EPR spectra of duplexes between 3 and 5-8 well correlated with Tm values. We also synthesized ODN 4 containing 2, which has a cyclic aminoxyl via a linker, to compare with ODN 3. The h(+)/h(0) values in the EPR spectra of duplexes between 4 and 5-8 did not correlate with Tm values. These results indicate that 1 has a potential to monitor of motion of the nucleobase.

Water-proton relaxivity of hyperbranched polymers carrying TEMPO radicals.

High water-soluble hyperbranched poly(styrene) (HPS) polymers carrying stable 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals, HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)(2), were prepared in ca. 60% introducing yield. HPS-N-TEMPO and HPS-Im-TEMPO were determined to be nearly spherical shapes of the diameter of 2.4 +/- 0.6 and 2.2 +/- 0.6 nm, respectively, by transmission electron microscope (TEM) images. The values of water-proton relaxivity, r(1), at 25 MHz, 0.59 T, and 25 degrees C were 6.0, 5.2, and 14 mM(-1) sec(-1) for HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)(2), respectively. The spin-lattice relaxation time (T(1))-weighted images in phantom were also observed.

Molecular structure and magnetic properties of 1-ethyl-2-(1-oxy-3-oxo-4,4,5,5-tetramethylimidazolin-2-yl)-3-methylimidazolium arylcarboxylates and other salts.

1-Ethyl-2-(1-oxy-3-oxo-4,4,5,5-tetramethylimidazolin-2-yl)-3-methylimidazolium bromide, [EMINN](+)[Br](-), carrying nitronylnitroxide (NN) in the cation unit, was prepared as a parent molecule and converted to seven salts, [EMINN](+)[X](-) (X = I, TFSI (bis(trifluoromethanesulfonyl)imide), BPh4 (tetraphenylborate), [EMINN](+)(1-3)[BA(1-3)]((1-3)-); BA1 (benzoic acid), BA2 (terephthalic acid), and BA3 (trimesic acid), and [EMINN](+)[BANN](-); BANN (4-NN-benzoic acid)), by the ion-exchange reaction. The molecular structure of the cation units for all salts revealed by X-ray crystallography is similar, where the dihedral angles between the imidazolium ring and the NN planes are 51-58 degrees. In the crystal structure, [EMINN](+)[X](-) (X = Br, I, TFSI, and BPh4) formed head-to-tail dimers, while the uniquely shaped dimers consisting of two [EMINN](+)[carboxylate](-) units were connected by the hydrogen bonding of water molecules to form a tape structure for [EMINN](+)[BANN](-) and 2D sheet structure for [EMINN](+)2[BA2](2-) and [EMINN](+)3[BA3](3-). In the crystalline state, [EMINN](+)[X](-) showed behavior typical of a paramagnetic species with S = 1/2. The chi(mol)T vs T plot for [EMINN](+)[BANN](-) was analyzed using a four-spin model to give J1/kB = -0.27 and J2/kB = -0.16 K. The plots for [EMINN](+)2[BA2](2-) and [EMINN](+)3[BA3](3-) were analyzed using an antiferromagnetic chain model to give J/kB = -62.1 and -86.5 K, respectively. In aqueous solution, on the other hand, the ESR spectra for all salts showed similar five-line signals due to the isolated NN moiety. The relaxivities (r1 and r2; 25 degrees C, 0.59 T, and 25 MHz) for [EMINN](+)[Br](-), [EMINN](+)[BA](-), [EMINN](+)[BANN](-), [EMINN](+)2[BA2](2-), and [EMINN](+)3[BA3](3-), are r1 = 0.13, 0.14, 0.32, 0.26, and 0.40 and r2 = 0.17, 0.13, 0.31, 0.30, and 0.46 mM(-1) s(-1), respectively.

Dynamics of 2-N-tert-butylaminoxyladenosine incorporated into oligodeoxynucleotides.

We synthesized oligodeoxynucleotide (ODN, 3) containing 2-N-tert-butylaminoxyladenosine (1) and studied EPR spectra of 1 and its duplexes with varied sequences. Duplex formation resulted in a broadening of spectrum and a significant decrease in peak-to-peak height and peak height ratio values. The h(+)/ho values in EPR spectra well correlated with stability of duplex which indicated ODN containing 1 has the potential to monitor DNA structure.

Synthesis and relaxivities of oligonucleotides with TEMPO-labeled sugar moiety.

5-Uridin derivative, UUT, having TEMPO radical at the 2'-position of sugar moiety, was prepared and characterized by X-ray crystallography. The single strands, ssUUT, incorporating UUT and the double strands, dsUUT, with complimentary strand were also obtained. Their EPR spectra and relaxivities (25 MHz and 0.59 T) in water were measured. The values of tau R obtained from the simulation of EPR spectra and the water-proton relaxivities, r1 and r2, increased in order of UUT, ssUUT, and dsUUT.

Water-proton relaxivities of DNA oligomers carrying TEMPO radicals.

5-Uridine derivative carrying a TEMPO radical (UST) was prepared and its single strand (ssUST) and a double strand (dsUST) with its complementary strand were obtained. Similarly, single strands carrying two and five radicals (ssUST2 and ssUST5, respectively) and the corresponding double strands (dsUST2 and dsUST5) were prepared. Their electron paramagnetic resonance (EPR) spectra showed typical anisotropic broadening in the high field line. The rotational correlation times, tau(R), estimated by analyzing the EPR spectra are 1.1 x 10(-10), 5.9 x 10(-10), and 14 x 10(-10) s for UST, ssUSTm, and dsUSTm, respectively. The water-proton relaxivities, r(1) and r(2), at 25 MHz, 0.59 T, and 25 degrees C, also increased in the same order and the r(1) values were 0.26, 0.41, and 0.56 mM(-1) s(-1) for UST, ssUSTm, and dsUSTm, respectively. The r(1) values of 1.00 and 2.06 mM(-1) s(-1) for dsUST2 and dsUST5, respectively, were obtained.

Cyclic single-molecule magnet in heterospin system.

The 2:2 complex of Co-carbene is generated by photolysis of [Co(hfpip)2(D2py2(TBA))]2, 1, having a cyclic structure functioning as a single-molecule magnet with Ueff = 96 K and Hc = 10 kOe at 1.9 K after annealing at 70 K.