Journal of the Chemical Society, Perkin Transactions 2, 2001
In the first paper of this series, we proposed a new absolute asymmetric synthesis (NAAS) with ci... more In the first paper of this series, we proposed a new absolute asymmetric synthesis (NAAS) with circularly polarized light (CPL), which can be classified into two subcategories: (a) reversible NAAS (CPL excites both the reactant and product), (b) irreversible NAAS (the reactant only is excited by CPL). In the present paper we deal with reversible NAAS. The numerical simulations, which are based upon the results of the preceding paper of this series, are performed. Using the reversible photoisomerization between methyl norbornadiene-2-carboxylate (I) and methyl quadricyclane-1-carboxylate (II), it was experimentally verified that the enantiomeric excesses (ee's) of both the reactant and product were critically dependant not only on the anisotropy factors (g = Δe/e) of both components, but also on the relative quantum yields of the forward and reverse reactions. In the case of reversible NAAS, the ee of the reactant and the product will concurrently increase according to the conversion, and attain appreciable values at the photostationary state if we appropriately select the system and the CPL-irradiation wavelength in such a way that if the g factors of the product and the reactant are large enough, the sign of the g factor of the product is opposite to that of the reactant, and the photochemical equilibrium constant K is less than unity.
This article focuses on heating or annealing process in the mechanochemical preparation of coordi... more This article focuses on heating or annealing process in the mechanochemical preparation of coordination compounds in the solid state. Heating of metal complexes often promotes the liberation of weakly coordinated ligands and results in the complex with its coordination geometry unsaturated. Such “activated” complexes can be used as the building blocks of coordination polymers in the solid state. As one example, our recent work on [M(CNacac)2]∞ (CNacac = 3-cyano-pentane-2,4-dionato, M = MnII, FeII, CoII, NiII, CuII and ZnII) is presented. Further, co-grinding and annealing treatments of an enantiomeric pair of chiral crystals of [M(phen)3](PF6)2 (M = RuII and OsII, phen = 1,10-phenanthoroline) afford diffusion and rearrangement of transition metal complex ions to form co-crystal phases of racemic or quasi-racemic compounds by way of recognizing chirality. Our latest result of co-crystal formation via chirality transfer between optically stable and labile metal complexes is also briefly introduced.
The Japanese Journal for Medical Virtual Reality, 2020
An anatomical model (manikin) that can be used for studying anatomy and training for surgery is r... more An anatomical model (manikin) that can be used for studying anatomy and training for surgery is required in the medical field. By stacking particles that are the same size as the cell, an anatomically accurate manikin would be produced. However, it is difficult to handle cell-sized particles, so we make a manikin by stacking particles with a diameter of 0.33 mm with controlled color and hardness. Manikin is made from two types of silicone oil, a pigment and a photocrosslinker. By irradiating ultraviolet light to silicone oil, silicone gel of any color and hardness would be made. First, a 0.33 mm thickness of transparent silicone gel sheet with dents arranged at intervals of 0.33 mm is produced. Next, a colored silicone oil is dropped into these dents and cured by ultraviolet light to produce a silicone gel sheet with colored particles. Finally, this silicone gel sheet is stacked to make a manikin. Since the hardness and color can be changed for each particle, the manikin is more accurately to the color and hardness of the human body. In this paper, the manikin material and modeling technique are proposed and confirmed by experiments.
A 1 : 1 complex of 6-O-a-~-glucosyl-~-cyclodextrin (GI-B-CD) with 4-(dimethy1amino)benzonitrile (... more A 1 : 1 complex of 6-O-a-~-glucosyl-~-cyclodextrin (GI-B-CD) with 4-(dimethy1amino)benzonitrile (DMABN) associates with itself in aqueous solutions at high concentrations into a 2:2 complex (homodimer). The 1:l complex of GI-B-CD with DMABN also makes a heterodimer (1:1:2 complex) by the association with a 1:l inclusion complex of another guest molecule such as 1-pentanol, benzene, anisole, and benzonitrile. The association of the complex is accompanied by a drastic change in the fluorescence spectrum of DMABN. The measurement of the fluorescence intensity as a function of the concentration of GI-B-CD gave the equilibrium constants for the association. The equilibrium constants were greatly dependent on the temperature, and the values for both AH and AS were largely negative. The fluorescence spectra of DMABN in the cavity of the dimers changed with exchanging the second guest compound, which implies that the second guest molecule plays the role of a polar solvent in the nonpolar environment in the cavity. The formation of homo-and heterodimers of the 1:l inclusion complex also takes place in the solutions containing other cyclodextrins and DMABN.
Journal of the Chemical Society, Perkin Transactions 2, 2001
In the first paper of this series, we proposed a new absolute asymmetric synthesis (NAAS) with ci... more In the first paper of this series, we proposed a new absolute asymmetric synthesis (NAAS) with circularly polarized light (CPL), which can be classified into two subcategories: (a) reversible NAAS (CPL excites both the reactant and product), (b) irreversible NAAS (the reactant only is excited by CPL). In the present paper we deal with reversible NAAS. The numerical simulations, which are based upon the results of the preceding paper of this series, are performed. Using the reversible photoisomerization between methyl norbornadiene-2-carboxylate (I) and methyl quadricyclane-1-carboxylate (II), it was experimentally verified that the enantiomeric excesses (ee's) of both the reactant and product were critically dependant not only on the anisotropy factors (g = Δe/e) of both components, but also on the relative quantum yields of the forward and reverse reactions. In the case of reversible NAAS, the ee of the reactant and the product will concurrently increase according to the conversion, and attain appreciable values at the photostationary state if we appropriately select the system and the CPL-irradiation wavelength in such a way that if the g factors of the product and the reactant are large enough, the sign of the g factor of the product is opposite to that of the reactant, and the photochemical equilibrium constant K is less than unity.
This article focuses on heating or annealing process in the mechanochemical preparation of coordi... more This article focuses on heating or annealing process in the mechanochemical preparation of coordination compounds in the solid state. Heating of metal complexes often promotes the liberation of weakly coordinated ligands and results in the complex with its coordination geometry unsaturated. Such “activated” complexes can be used as the building blocks of coordination polymers in the solid state. As one example, our recent work on [M(CNacac)2]∞ (CNacac = 3-cyano-pentane-2,4-dionato, M = MnII, FeII, CoII, NiII, CuII and ZnII) is presented. Further, co-grinding and annealing treatments of an enantiomeric pair of chiral crystals of [M(phen)3](PF6)2 (M = RuII and OsII, phen = 1,10-phenanthoroline) afford diffusion and rearrangement of transition metal complex ions to form co-crystal phases of racemic or quasi-racemic compounds by way of recognizing chirality. Our latest result of co-crystal formation via chirality transfer between optically stable and labile metal complexes is also briefly introduced.
The Japanese Journal for Medical Virtual Reality, 2020
An anatomical model (manikin) that can be used for studying anatomy and training for surgery is r... more An anatomical model (manikin) that can be used for studying anatomy and training for surgery is required in the medical field. By stacking particles that are the same size as the cell, an anatomically accurate manikin would be produced. However, it is difficult to handle cell-sized particles, so we make a manikin by stacking particles with a diameter of 0.33 mm with controlled color and hardness. Manikin is made from two types of silicone oil, a pigment and a photocrosslinker. By irradiating ultraviolet light to silicone oil, silicone gel of any color and hardness would be made. First, a 0.33 mm thickness of transparent silicone gel sheet with dents arranged at intervals of 0.33 mm is produced. Next, a colored silicone oil is dropped into these dents and cured by ultraviolet light to produce a silicone gel sheet with colored particles. Finally, this silicone gel sheet is stacked to make a manikin. Since the hardness and color can be changed for each particle, the manikin is more accurately to the color and hardness of the human body. In this paper, the manikin material and modeling technique are proposed and confirmed by experiments.
A 1 : 1 complex of 6-O-a-~-glucosyl-~-cyclodextrin (GI-B-CD) with 4-(dimethy1amino)benzonitrile (... more A 1 : 1 complex of 6-O-a-~-glucosyl-~-cyclodextrin (GI-B-CD) with 4-(dimethy1amino)benzonitrile (DMABN) associates with itself in aqueous solutions at high concentrations into a 2:2 complex (homodimer). The 1:l complex of GI-B-CD with DMABN also makes a heterodimer (1:1:2 complex) by the association with a 1:l inclusion complex of another guest molecule such as 1-pentanol, benzene, anisole, and benzonitrile. The association of the complex is accompanied by a drastic change in the fluorescence spectrum of DMABN. The measurement of the fluorescence intensity as a function of the concentration of GI-B-CD gave the equilibrium constants for the association. The equilibrium constants were greatly dependent on the temperature, and the values for both AH and AS were largely negative. The fluorescence spectra of DMABN in the cavity of the dimers changed with exchanging the second guest compound, which implies that the second guest molecule plays the role of a polar solvent in the nonpolar environment in the cavity. The formation of homo-and heterodimers of the 1:l inclusion complex also takes place in the solutions containing other cyclodextrins and DMABN.
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Papers by Asao NAKAMURA