Hardness and slip systems of orthorhombic hen egg-white lysozyme crystals

Hardness and slip systems by an indentation method were investigated on different habit planes of orthorhombic hen egg-white lysozyme (O-HEWL) crystals containing water. A dependence of the hardness on the water-evaporation time exhibits three stages as incubation, transition and saturated ones, as tetragonal (T)-HEWL crystals reported previously. The hardness values of (1 1 0), (0 1 0) and (0 1 1) habit planes of O-HEWL in the incubation stage or wet condition exhibits 6, 8 and 10 MPa, respectively. The hardness depends on indented planes but it is independent of the air-humidity and crystal volumes. These values correspond to the intrinsic hardness for O-HEWL crystals containing water. In the incubation stage, the slip traces are clearly observed around the indentation mark and the corresponding six kinds of slip systems are identified to be {0 1 1}<1 0 0>, {1 1 0}<1 1 0>, {0 1 1}<0 1 1>, {1 1 0}<0 0 1>, {1 0 0}<0 0 1> and {0 1 0}<0 0 1>.     

Improved Crystallinity of Poly(3-hexylthiophene-2,5-diyl):[6,6]-Phenyl-C61 Butyric Acid Methyl Ester Film by Pulsed Electrospray Deposition

We investigated crystallinity parameters and ordering domains of poly(3-hexylthiophene-2,5-diyl) blended in [6,6]-phenyl-C₆₁-butyric acid methyl ester films, which were fabricated by pulsed electrospray deposition methods. The crystallinity parameter and the ordering domain were estimated from Raman and optical absorption spectra, respectively. As a result, they were improved with decreasing the off time of pulse voltage, corresponding to the slow evaporation speed of solvent. In addition, both the space-charge limited current mobility and the photoconversion efficiency showed same trend. A highest photoconversion efficiency of 1.11 % was achieved without the thermal annealing process after depositing the active layer.     

A new method to improve validity range of Lie canonical perturbation theory: with a central focus on a concept of non-blow-up region

Validity ranges of Lie canonical perturbation theory (LCPT) are investigated in terms of non-blow-up regions. We investigate how the validity ranges depend on the perturbation order in two systems, one of which is a simple Hamiltonian system with one degree of freedom and the other is a HCN molecule. Our analysis of the former system indicates that non-blow-up regions become reduced in size as the perturbation order increases. In case of LCPT by Dragt and Finn and that by Deprit, the non-blow-up regions enclose the region inside the separatrix of the Hamiltonian, but it may not be the case for LCPT by Hori. We also analyze how well the actions constructed by these LCPTs approximate the true action of the Hamiltonian in the non-blow-up regions and find that the conventional truncated LCPT does not work over the whole region inside the separatrix, whereas LCPT by Dragt and Finn without truncation does. Our analysis of the latter system indicates that non-blow-up regions do not necessarily cover the whole regions inside the HCN well. We propose a new perturbation method to improve non-blow-up regions and validity ranges inside them. Our method is free from blowing up and retains the same normal form as the conventional LCPT. We demonstrate our method in the two systems and show that the actions constructed by our method have larger validity ranges than those by the conventional and our previous methods proposed in Teramoto and Komatsuzaki (J Chem Phys 129:094302, 2008; Phys Rev E 78:017202, 2008).     

Robust Inclusion Complexes of Crown Ether Fused Tetrathiafulvalenes with Li+@C60 to Afford Efficient Photodriven Charge Separation

Inclusion complexes of benzo‐ and dithiabenzo‐crown ether functionalized monopyrrolotetrathiafulvalene (MPTTF) molecules were formed with Li⁺@C₆₀ ( 1? Li⁺@C₆₀ and 2? Li⁺@C₆₀). The strong complexation has been quantified by high binding constants that exceed 10⁶ M ^?1 obtained by UV/Vis titrations in benzonitrile (PhCN) at room temperature. On the basis of DFT studies at the B3LYP/6‐311G(d,p) level, the orbital interactions between the crown ether moieties and the π surface of the fullerene together with the endohedral Li⁺ have a crucial role in robust complex formation. Interestingly, complexation of Li⁺@C₆₀ with crown ethers accelerates the intersystem crossing upon photoexcitation of the complex, thereby yielding ³(Li⁺@C₆₀)*, when no charge separation by means of ¹Li⁺@C₆₀* occurs. Photoinduced charge separation by means of ³Li⁺@C₆₀* with lifetimes of 135 and 120 μs for 1? Li⁺@C₆₀ and 2? Li⁺@C₆₀, respectively, and quantum yields of 0.82 in PhCN have been observed by utilizing time‐resolved transient absorption spectroscopy and then confirmed by electron paramagnetic resonance measurements at 4 K. The difference in crown ether structures affects the binding constant and the rates of photoinduced electron‐transfer events in the corresponding complex.     

Unsymmetrical Pincer‐Type Ruthenium Complex Containing β‐Protic Pyrazole and N‐Heterocyclic Carbene Arms: Comparison of Brønsted Acidity of NH Groups in Second Coordination Sphere

A reaction of a 2‐(imidazol‐1‐yl)methyl‐6‐(pyrazol‐3‐yl)pyridine with [RuCl₂(PPh₃)₃] resulted in tautomerization of the imidazole unit to afford the unsymmetrical pincer‐type ruthenium complex 2 containing a protic pyrazole and N‐heterocyclic carbene (NHC) arms. Deprotonation of 2 with one equivalent of a base led to the formation of the NHC–pyrazolato complex 3 , indicating that the protic NHC arm is less acidic. When 2 was treated with two equivalents of a base under H₂ or in 2‐propanol, the hydrido complex 4 containing protic NHC and pyrazolato groups was obtained through metal–ligand cooperation.     

Photochemical Behavior of Single‐Walled Carbon Nanotubes in the Presence of Propylamine

This report describes the photochemical behavior of single‐walled carbon nanotubes (SWNTs) in the presence of propylamine. The SWNTs are characterized by absorption and Raman spectroscopy. The spectral changes due to photoirradiation indicate that reactions occur predominantly with the metallic SWNTs and small‐diameter SWNTs. The detection of amine radicalcation species by ESR spectroscopy reveals photoinduced electron transfer from the amine to the excited SWNTs. After exposure of the photoirradiated SWNTs to air, the characteristic spectra were recovered, except for that of the small‐diameter SWNTs. The results suggest that, after photoreduction of the SWNTs, subsequent selective sidewall functionalization of the small‐diameter SWNTs occurs.     

Multiple Fused Anthracenes as Helical Polycyclic Aromatic Hydrocarbon Motif for Chiroptical Performance Enhancement

Polycyclic aromatic hydrocarbons consisting of three fused anthracene units were designed as new π‐conjugated compounds having helical structures. These expanded helicenes were synthesized by Pt‐catalyzed cycloisomerization of the corresponding ethynyl‐substituted precursors. The nonplanar and helical structure was confirmed by X‐ray analysis and DFT calculations, and the barrier to helical inversion was estimated to be 34 kJ mol^?1. The enantiomers of the diphenyl derivative were successfully resolved by chiral HPLC. Enantiopure samples showed good chiroptical performance in the CD (|Δ?| 1380 L mol^?1 cm^?1) and CPL (|g_lum| 0.013) spectra, and these values were considerably large for simple organic molecules. The unique chiroptical properties are discussed on the basis of the molecular structure and the electronic state with the aid of time‐dependent DFT calculations.     

Enantioselective Protonation of Cyclic Carbonyl Ylides by Chiral Lewis Acid Assisted Alcohols

Chiral Lewis acid-catalyzed asymmetric alcohol addition reactions to cyclic carbonyl ylides generated from N-(α-diazocarbonyl)-2-oxazolidinones featuring a dual catalytic system are reported. Construction of a chiral quaternary heteroatom-substituted carbon center was accomplished in which the unique heterobicycles were obtained in good yields with high stereoselection. The alcohol adducts were successfully converted to optically active oxazolidine-2,4-diones by hydrolysis. Mechanistic studies by DFT calculations revealed that alcohols could be activated by Lewis acids, enabling enantioselective protonation of the carbonyl ylides.     

Solubility Switching of Metallophthalocyanines and Their Larger Derivatives upon Encapsulation

Metallophthalocyanines (MPcs) are very useful pigments but scarcely soluble without appropriate functional groups in common solvents. Herein, we report that bent polyaromatic amphiphiles act as excellent solubilizing reagents for nonfunctionalized MPcs and larger MPc derivatives (e.g., CuPc, perhalogenated CuPcs, Cu‐naphthalocyanine, CuPc polymers, and double‐decker MPcs) in neutral water upon encapsulation. The resultant MPc nanocomposites display high stability towards heat and pH change. More importantly, the encapsulated MPcs can be released by simple protocols under mild conditions both into a bulk solvent and onto glass or polymer plates.