Preoperative Simulation of Ileal Pouch-Anal Anastomosis in Patients With Ulcerative Colitis Using a 3-Dimensional Printed Model.

BACKGROUND: During restorative proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis-associated colorectal cancer or dysplasia, ileal pouch-anal handsewn anastomosis (IAA) is preferred to avoid the risk of cancer development in the remaining rectal mucosa. However, there is a risk of the ileal pouch not reaching the anus with this procedure. Here, we created deformable 3-dimensional (3D) models for simulation. METHOD: Six patients who underwent IAA without vessel ligation and 5 patients who underwent ileal pouch-anal canal double-stapled anastomosis (IACA) because the ileal pouch did not reach the anus were studied. A 3D printer was used to create deformable 3D models from the data obtained from computed tomography scans. The positional relationship among the mesenteric arteries, pubis, and coccyx were evaluated. RESULT: The distance between the superior mesenteric artery root and the tip of the ileal artery was longer in the IAA group than that in the IACA group (IAA vs IACA: 26.2 ±â€…2.1 cm vs 20.9 ±â€…1.6cm). The distance from the tip of the ileal artery to the coccyx (IAA vs IACA: 6.7 ±â€…1.7 cm vs 12.1 ±â€…2.1 cm) and the distance from the tip of the ileal artery to the lower edge of the pubis (IAA vs IACA; 8.1 ±â€…1.3 cm vs 12.7 ±â€…2.4 cm) were longer in the IACA group than those in the IAA group. CONCLUSIONS: We established a method for creating 3D deformable models of patients with ileal pouch-anal anastomosis. These 3D models may be useful for preoperative simulation.

We established the method for creating deformable 3-dimensional models of the patients who underwent restorative proctocolectomy with ileal pouch­anal anastomosis, and the distance from the tip of the ileal artery to the coccyx was shorter in ileal pouch­anal handsewn anastomosis group.

Near- and Mid-IR Gas-Phase Absorption Spectra of H2@C60+-He.

Near- and mid-IR absorption spectra of endohedral H2@C60+ have been measured using He-tagging. The samples have been prepared using a "molecular surgery" synthetic approach and were ionized and spectroscopically characterized in the gas phase. In contrast to neutral C60 and H2@C60, the corresponding He-tagged cationic species show distinct spectral differences. Shifts and line splittings in the near- and mid-IR regions indicate the influence of the caged hydrogen molecule on both the electronic ground and excited states. Possible relevance to astronomy is discussed.

Professor Tetsuo Nozoe and my tropylium ion chemistry.

Needless to say, the discovery of hinokitiol with its "unconventional" aromaticity by Professor Tetsuo Nozoe is one of the most important achievements in organic chemistry in the last century. The essence of this "non-benzenoid" aromaticity in hinokitiol is of course that of tropolone, and it is further related to the aromaticity of tropone and the tropylium ion, i.e., the cycloheptatrienyl cation. In this account, details of the study conducted by the author's group, particularly on the synthesis and properties of tropylium ion derivatives with various unique structures pursuing the ultimately high carbocation stability, are described.

Electrochemistry of the self-assembled monolayers of dyads consisting of tripod-shaped trithiol and bithiophene on gold.

Self-assembled monolayers (SAMs) of tripod-shaped trithiols, consisting of an adamantane core with three CH2SH legs and a bithiophene group, were prepared on a Au(111) surface. Adsorption in a tripod-like fashion was supported by polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS) of the SAMs, which indicated the absence of free SH groups. Cyclic voltammetry showed an irreversible cathodic wave due to reductive desorption. The SAM also showed an anodic wave due to the single-electron oxidation of the bithiophene moiety without concomitant desorption of the molecules. Although oxidation was irreversible in the absence of a protecting group, it became reversible with the introduction of a terminal phenyl group. The charge of the oxidation was one-third that of the reductive desorption, confirming a three-point adsorption. The surface coverage was ca. 50% of that expected for the anti bithiophene conformation, which suggested that an increase in the surface area per molecule had been caused by the presence of an energetically high-lying syn conformer. In accordance with this, the line shape of the oxidation wave suggested an electrostatic repulsive interaction between neighboring molecules.

Catalytic stereodivergent functionalization of H2@C60.

A complete stereocontrol of 1,3-dipolar cycloaddition of N-metalated azomethine ylides onto endohedral fullerene H2@C60 is reported for the first time. The stereodivergent synthesis of either the cis or the trans endohedral cycloadduct is achieved with excellent diastereo- and enantioselectivities.

Recognition of hydrogen isotopomers by an open-cage fullerene.

We present our study on the recognition of hydrogen isotopes by an open-cage fullerene through determination of binding affinity of isotopes H2/HD/D2 with the open-cage fullerene and comparison of their relative molecular sizes through kinetic-isotope-release experiments. We took advantage of isotope H2/D2 exchange that generated an equilibrium mixture of H2/HD/D2 in a stainless steel autoclave to conduct high-pressure hydrogen insertion into an open-cage fullerene. The equilibrium constants of three isotopes with the open-cage fullerene were determined at various pressures and temperatures. Our results show a higher equilibrium constant for HD into open-cage fullerene than the other two isotopomers, which is consistent with its dipolar nature. D2 molecule generally binds stronger than H2 because of its heavier mass; however, the affinity for H2 becomes larger than D2 at lower temperature, when size effect becomes dominant. We further investigated the kinetics of H2/HD/D2 release from open-cage fullerene, proving their relative escaping rates. D2 was found to be the smallest and H2 the largest molecule. This notion has not only supported the observed inversion of relative binding affinities between H2 and D2, but also demonstrated that comparison of size difference of single molecules through non-convalent kinetic-isotope effect was applicable.

Molecular surgical synthesis of H2@C60: recollections.

The first synthesis of endohedral fullerene containing molecular hydrogen, H2@C60, is briefly summarized. The synthesis was conducted according to what we call the 'molecular surgical method', that is, opening a hole on a C60 surface, enlargement of the hole, insertion of a guest species and enclosure of the hole without loss of the encapsulated guest. The entire process involves three chemical reactions to open the hole and four reactions to gradually reduce the hole size and finally close the hole. The total yield of the product, H2@C60, based on consumed C60 was 9%. The encapsulated molecule of hydrogen exhibited a 6 ppm upfield-shifted ¹H NMR signal when compared with free hydrogen, indicating the aromaticity at the inner centre of the C60 cage.

Probing the C60 triplet state coupling to nuclear spins inside and out.

The photoexcitation of functionalized fullerenes to their paramagnetic triplet electronic state can be studied by pulsed electron paramagnetic resonance (EPR) spectroscopy, whereas the interactions of this state with the surrounding nuclear spins can be observed by a related technique: electron nuclear double resonance (ENDOR). In this study, we present EPR and ENDOR studies on a functionalized exohedral fullerene system, dimethyl[9-hydro (C60-Ih)[5,6]fulleren-1(9H)-yl]phosphonate (DMHFP), where the triplet electron spin has been used to hyperpolarize, couple and measure two nuclear spins. We go on to discuss the extension of these methods to study a new class of endohedral fullerenes filled with small molecules, such as H2@C60, and we relate the results to density functional calculations.

Steric control in the π-dimerization of oligothiophene radical cations annelated with bicyclo[2.2.2]octene units.

A Two series of oligothiophenes 2(nT) (n=4,5), annelated with bicyclo[2.2.2]octene (BCO) units at both ends, and quaterthiophenes 3 a-c, annelated with various numbers of BCO units at different positions, were newly synthesized to investigate the driving forces of π-dimerization and the structure-property relationships of the π-dimers of oligothiophene radical cations. Their radical-cation salts were prepared through chemical one-electron oxidation by using nitrosonium hexafluoroantimonate. From variable-temperature electron spin resonance and electronic absorption measurements, the π-dimerization capability was found to vary among the members of the 2(nT)(+)(·)SbF6(-) series and 3(+)(·)SbF6(-) series of compounds. To examine these results, density functional theory (DFT) calculations at the M06-2X/6-31G(d) level were conducted for the π-dimers. This level of theory was found to successfully reproduce the previously reported X-ray structure of (2(3T))2(2+) having a bent π-dimer structure with cis-cis conformations. The absorption bands obtained by time-dependent DFT calculations for the π-dimers were in reasonable agreement with the experimental spectra. The attractive and repulsive forces for the π-dimerization were divided into four factors: 1) SOMO-SOMO interactions, 2) van der Waals forces, 3) solvation, and 4) Coulomb repulsion, and the effects of each factor on the structural differences and chain-length dependence are discussed in detail.

Ideal redox behavior of the high-density self-assembled monolayer of a molecular tripod on a Au(111) surface with a terminal ferrocene group.

A dyad consisting of a tripod-shaped trithiol with an adamantane core and a terminal ferrocenyl group linked through ap-phenyleneethynylene bridge was synthesized. The trithiol formed a stable self-assembled monolayer (SAM) on Au(111), wherein each molecule is bound to the surface by three-point adsorption using all sulfur atoms, with confirmation by PM-IRRAS and XPS analyses. Cyclic voltammetry of the SAM showed a line shape typical of an ideal adsorbed system, that is, a monolayer with negligible electrostatic interaction among the terminal ferrocenyl groups. Thus, a rare SAM was achieved, in which the component molecules were isolated from adjacent molecules without the coadsorption of nonelectroactive molecules.

X-ray observation of a helium atom and placing a nitrogen atom inside He@C60 and He@C70.

Single crystal X-ray analysis has been used as a powerful method to determine the structure of molecules. However, crystallographic data containing helium has not been reported, owing to the difficulty in embedding helium into crystalline materials. Here we report the X-ray diffraction study of He@C60 and the clear observation of a single helium atom inside C60. In addition, the close packing of a helium atom and a nitrogen atom inside fullerenes is realized using two stepwise insertion techniques, that is, molecular surgery to synthesize the fullerenes encapsulating a helium atom, followed by nitrogen radio-frequency plasma methods to generate the fullerenes encapsulating both helium and nitrogen atoms. Electron spin resonance analysis reveals that the encapsulated helium atom has a small but detectable influence on the electronic properties of the highly reactive nitrogen atom coexisting inside the fullerene, suggesting the potential usage of helium for controlling electronic properties of reactive species.

ENDOR evidence of electron-H2 interaction in a fulleride embedding H2.

An endofulleropyrrolidine, with H2 as a guest, has been reduced to a paramagnetic endofulleride radical anion. The magnetic interaction between the electron delocalized on the fullerene cage and the guest H2 has been probed by pulsed ENDOR. The experimental hyperfine couplings between the electron and the H2 guest were measured, and their values agree very well with DFT calculations. This agreement provides clear evidence of magnetic communication between the electron density of the fullerene host cage and H2 guest. The ortho-H2/para-H2 interconversion is revealed by temperature-dependent ENDOR measurements at low temperature. The conversion of the paramagnetic ortho-H2 to the diamagnetic para-H2 causes the ENDOR signal to decrease as the temperature is lowered due to the spin catalysis by the paramagnetic fullerene cage of the radical anion fulleride.

Synthesis, isomer count, and nuclear spin relaxation of H2O@open-C60 nitroxide derivatives.

H(2)O@C(60) derivatives covalently linked to a nitroxide radical were synthesized. The (1)H NMR of the guest H(2)O revealed the formation of many isomers with broad signals. Reduction to the diamagnetic hydroxylamines sharpened the (1)H NMR signals considerably and allowed for an "isomer count" based on the number of observed distinct signals. For H(2)O@K-8, 17 positional isomeric nitroxides are predicted, not including additional numbers of regioisomers; indeed, 17 signals are observed in the (1)H NMR spectrum.

Comparison of Nuclear Spin Relaxation of H2O@C60 and H2@C60 and Their Nitroxide Derivatives.

The successful synthesis of H2O@C60 makes possible the study of magnetic interactions of an isolated water molecule in a geometrically well-defined hydrophobic environment. Comparisons are made between the T1 values of H2O@C60 and the previously studied H2@C60 and their nitroxide derivatives. The value of T1 is approximately six times longer for H2O@C60 than for H2@C60 at room temperature, is independent of solvent viscosity or polarity, and increases monotonically with decreasing temperature, implying that T1 is dominated by the spin-rotation interaction. Paramagnetic nitroxides, either attached covalently to the C60 cage or added to the medium, produce strikingly similar T1 enhancements for H2O@C60 and H2@C60 that are consistent with through-space interaction between the internal nuclear spins and the external electron spin. This indicates that it should be possible to apply to the endo-H2O molecule the same methodologies for manipulating the ortho and para spin isomers that have proven successful for H2@C60.

Indirect 1H NMR characterization of H2@C60 nitroxide derivatives and their nuclear spin relaxation.

(1)H NMR of two H(2)@C(60) nitroxide derivatives has been characterized indirectly by reducing to their corresponding hydroxylamines. Nuclear spin relaxation of the endohedral H(2) and external protons of the H(2)@C(60) nitroxide and its corresponding hydroxylamine were measured and analyzed. The observed spectra are consistent with negligible scalar coupling between the unpaired electron and the endo-H(2). An unexpectedly large bimolecular relaxivity induced in the hydroxylamine by the corresponding nitroxide can be explained by rapid hydrogen atom transfer between the two species.

A photochemical on-off switch for tuning the equilibrium mixture of H2 nuclear spin isomers as a function of temperature.

The photochemical interconversion of the two allotropes of the hydrogen molecule [para-H(2) (pH(2)) and ortho-H(2) (oH(2))] incarcerated inside the fullerene C(70) (pH(2)@C(70) and oH(2)@C(70), respectively) is reported. Photoexcitation of H(2)@C(70) generates a fullerene triplet state that serves as a spin catalyst for pH(2)/oH(2) conversion. This method provides a means of changing the pH(2)/oH(2) ratio inside C(70) by simply irradiating H(2)@C(70) at different temperatures, since the equilibrium ratio is temperature-dependent and the electronic triplet state of the fullerene produced by absorption of the photon serves as an "on-off" spin catalyst. However, under comparable conditions, no photolytic pH(2)/oH(2) interconversion was observed for H(2)@C(60), which was rationalized by the significantly shorter triplet lifetime of H(2)@C(60) relative to H(2)@C(70).

Allyl radical nature of a phenylcyclopentadienyl radical annelated with two homoadamantene frameworks.

1-Phenylcyclopentadiene fused with two homoadamantene units at the 2,3- and 4,5-positions (4) was deprotonated with KH to lead to the quantitative formation of the corresponding cyclopentadienyl (Cp) anion 3(-). This anion was oxidized by AgCl to afford an orange crystalline solid consisting of Cp radical 3(•) and cyclopentadiene 4. The ESR spectrum in hexane exhibited approximately 15 lines, demonstrating that the two homoadamantene frameworks were equivalent and that the C1-C2(Ph)-C3 moiety of the five-membered ring formed a symmetrical allyl-like radical in agreement with the prediction by DFT calculation. The reaction of the Cp radical 3(•) with an oxygen molecule in the presence of Ag(+)SbF(6)(-) afforded the SbF(6)(-) salt of a phenylpyrylium ion annelated with two homoadamantene frameworks (8(+)SbF(6)(-)).

Synthesis and characterization of bispyrrolidine derivatives of H2@C60: differentiation of isomers using 1H NMR spectroscopy of endohedral H2.

Bisadduct isomers of a H(2)@C(60) derivative with nitroxide addends have been synthesized, isolated and characterized. The (1)H NMRs of endohedral H(2) of the major isomers show well-separated chemical shifts, which could be useful for structural assignment and identification of the purity of the C(60) bisadduct isomers.