Lewis-Pairing-Induced Electrochemiluminescence Enhancement from Electron Donor-Acceptor Diads Decorated with Tris(pentafluorophenyl)borane as an Electrochemical Protector.

This study reports an effective peripheral decoration of organic donor-acceptor diads with B(C6 F5 )3 for stabilizing electrogenerated radical ions. By employing a common p-type organic semiconductor benzothienobenzothiophene (BTBT) as the donor, tetracoordinate boron complexes showed improved solution electrochemiluminescence (ECL) intensity, reaching a 156-fold increase compared to that of the parent diad. The unprecedented Lewis-pairing-induced ECL enhancement is attributed to the multiple roles of B(C6 F5 )3 : 1) redistributing frontier orbitals, 2) facilitating electrochemical excitation, and 3) restricting molecular motions. Furthermore, B(C6 F5 )3 converted the molecular arrangement of BTBT from conventional 2D herringbones into 1D π-stacks. This robust, highly ordered columnar nanostructure allowed red-shifting of the crystalline film ECL with electrochemical doping through the electronic coupling pathways of BTBT. Our approach will facilitate the development of elaborate metal-free ECL systems.

Analysis of cell death in Bacillus subtilis caused by sesquiterpenes from Chrysopogon zizanioides (L.) Roberty.

Recently, the antibacterial effects of essential oils have been investigated in addition to their therapeutic purposes. Owing to their hydrophobic nature, they are thought to perturb the integrity of the bacterial cell membrane, leading to cell death. Against such antibiotic challenges, bacteria develop mechanisms for cell envelope stress responses (CESR). In Bacillus subtilis, a gram-positive sporulating soil bacterium, the extracytoplasmic function (ECF) sigma factor-mediated response system plays a pivotal role in CESR. Among them, σM is strongly involved in response to cell envelope stress, including a shortage of available bactoprenol. Vetiver essential oil, a product of Chrysopogon zizanioides (L.) Roberty root, is also known to possess bactericidal activity. σM was exclusively and strongly induced when the cells were exposed to Vetiver extract, and depletion of multi-ECF sigma factors (ΔsigM, ΔsigW, ΔsigX, and ΔsigV) enhanced sensitivity to it. From this quadruple mutant strain, the suppressor strains, which restored resistance to the bactericidal activity of Vetiver extract, emerged, although attempts to obtain resistant strains from the wild type did not succeed. Whole-genome resequencing of the suppressor strains and genetic analysis revealed inactivation of xseB or pnpA, which code for exodeoxyribonuclease or polynucleotide phosphorylase, respectively. This allowed the quadruple mutant strain to escape from cell death caused by Vetiver extract. Composition analysis suggested that the sesquiterpene, khusimol, might contribute to the bactericidal activity of the Vetiver extract.

Solid-State Structures and Photoluminescence of Lamellar Architectures of Cu(I) and Ag(I) Paddlewheel Clusters with Hydrogen-Bonded Polar Guests.

Two hexanuclear paddlewheel-like clusters appending six carboxylic-acid pendants have been isolated with the inclusion of polar solvent guests: [Cu6(Hmna)6]·7DMF (1·7DMF) and [Ag6(Hmna)6]·8DMSO (2·8DMSO), where H2mna = 2-mercaptonicotininc acid, DMF = N,N'-dimethylformamide, and DMSO = dimethyl sulfoxide. The solvated clusters, together with their fully desolvated forms 1 and 2, have been characterized by FTIR, UV-Vis diffuse reflectance spectroscopy, TG-DTA analysis, and DFT calculations. Crystal structures of two solvated clusters 1·7DMF and 2·8DMSO have been unambiguously determined by single-crystal X-ray diffraction analysis. Six carboxylic groups appended on the clusters trap solvent guests, DMF or DMSO, through H-bonds. As a result, alternately stacked lamellar architectures comprising of a paddlewheel cluster layer and H-bonded solvent layer are formed. Upon UV illumination (λex = 365 nm), the solvated hexasilver(I) cluster 2·8DMSO gives intense greenish-yellow photoluminescence in the solid state (λPL = 545 nm, ΦPL = 0.17 at 298 K), whereas the solvated hexacopper(I) cluster 1·7DMF displays PL in the near-IR region (λPL = 765 nm, ΦPL = 0.38 at 298 K). Upon complete desolvation, a substantial bleach in the PL intensity (ΦPL < 0.01) is observed. The desorption-sorption response was studied by the solid-state PL spectroscopy. Non-covalent interactions in the crystal including intermolecular H-bonds, CH⋯π interactions, and π⋯π stack were found to play decisive roles in the creation of the lamellar architectures, small-molecule trap-and-release behavior, and guest-induced luminescence enhancement.

Immobilizing a π-Conjugated Catecholato Framework on Surfaces of SiO2 Insulator Films via a One-Atom Anchor of a Platinum Metal Center to Modulate Organic Transistor Performance.

Chemical modification of insulating material surfaces is an important methodology to improve the performance of organic field-effect transistors (OFETs). However, few redox-active self-assembled monolayers (SAMs) have been constructed on gate insulator film surfaces, in contrast to the numerous SAMs formed on many types of conducting electrodes. In this study, we report a new approach to introduce a π-conjugated organic fragment in close proximity to an insulating material surface via a transition metal center acting as a one-atom anchor. On the basis of the reported coordination chemistry of a catecholato complex of Pt(II) in solution, we demonstrate that ligand exchange can occur on an insulating material surface, affording SAMs on the SiO2 surface derived from a newly synthesized Pt(II) complex containing a benzothienobenzothiophene (BTBT) framework in the catecholato ligand. The resultant SAMs were characterized in detail by water contact angle measurements, X-ray photoelectron spectroscopy, atomic force microscopy, and cyclic voltammetry. The SAMs served as good scaffolds of π-conjugated pillars for forming thin films of a well-known organic semiconductor C8-BTBT (2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene), accompanied by the engagements of the C8-BTBT molecules with the SAMs containing the common BTBT framework at the first layer on SiO2. OFETs containing the SAMs displayed improved performance in terms of hole mobility and onset voltage, presumably because of the unique interfacial structure between the organic semiconducting and inorganic insulating layers. These findings provide important insight into creating new elaborate interfaces through installing coordination chemistry in solution to solid surfaces, as well as OFET design by considering the compatibility between SAMs and organic semiconductors.

Ferrocene on Insulator: Silane Coupling to a SiO2 Surface and Influence on Electrical Transport at a Buried Interface with an Organic Semiconductor Layer.

A silane coupling-based procedure for decoration of an insulator surface containing abundant hydroxy groups by constructing redox-active self-assembled monolayers (SAMs) is described. A newly synthesized ferrocene (Fc) derivative containing a triethoxysilyl group designated FcSi was immobilized on SiO2/Si by a simple operation that involved immersing the substrate in a toluene solution of the Fc silane coupling reagent and then rinsing the resulting substrate. X-ray photoelectron spectroscopy (XPS) measurements confirmed that the Fc group was immobilized on SiO2/Si in the Fe(II) state. Cyclic voltammetry measurements showed that the Fc groups were electrically insulated from the Si electrode by the SiO2 layer. The FcSi on SiO2/Si structures were found to serve as a good scaffold for formation of organic semiconductor thin films by vacuum thermal evaporation of C8-BTBT (2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene), which is well-known as an organic field-effect transistor (OFET) material. The X-ray diffraction profile indicated that the conventional standing-up conformation of the C8-BTBT molecules perpendicular to the substrates was maintained in the thin films formed on FcSi@SiO2/Si. Further vacuum thermal evaporation of Au provided an FcSi-based OFET structure with good transfer characteristics. The FcSi-based OFET showed pronounced source-drain current hysteresis between the forward and backward scans. The degree of this hysteresis was varied reversibly via gate bias manipulation, which was presumably accompanied by trapping and detrapping of hole carriers at the Fc-decorated SiO2 surface. These findings provide new insights into application of redox-active SAMs to nonvolatile OFET memories while also creating new interfaces through junctions with functional thin films, in which the underlying redox-active SAMs play supporting roles.

A non-linear phenomenon observed in the photochromic crystals of a rhodium dithionite complex with n-propyl moieties.

Crystalline-state photochromism of a rhodium dithionite complex with n-propyl moieties was studied directly by performing single crystal X-ray diffraction experiments; a non-linear relationship between the degree of the conformational change of the n-propyl moiety and the degree of the photochromic reaction of the dithionite group (µ-O2SSO2) was observed at -173 °C.

Zwitterionic Mixed Valence: Internalizing Counteranions into a Biferrocenium Framework toward Molecular Expression of Half-Cells in Quantum Cellular Automata.

Realization of molecular quantum cellular automata (QCA), a promising architecture for molecular computing through current-free processes, requires improved understanding and application of mixed-valence (MV) molecules. In this report, we present an electrostatic approach to creating MV subspecies through internalizing opposite charges in close proximity to MV ionic moieties. This approach is demonstrated by unsymmetrically attaching a charge-responsive boron substituent to a well-known organometallic MV complex, biferrocenium. Guest anions (CN- and F- ) bind to the Lewis acidic boron center, leading to unusual blue-shifts of the intervalence charge-transfer (IVCT) bands. To the best of our knowledge, this is the first reported example of a zwitterionic MV series in which the degree of positive charge delocalization can be varied by changing the bound anions, and serves to clarify the interplay between IVCT parameters. The key underlying factor is the variable zero-level energy difference in the MV states. This work provides new insight into imbuing MV molecules with external charge-responsiveness, a prerequisite of molecular QCA techniques.

Charge-Separated Mixed Valency in an Unsymmetrical Acceptor-Donor-Donor Triad Based on Diarylboryl and Triarylamine Units.

In this study, we report the generation of new mixed-valence (MV) subspecies with charge-separated (CS) characters from an unsymmetrical acceptor-donor-donor (A-D-D) triad. The triad was synthesized by attaching a dimesitylboryl group (A) to a D-D conjugate that consisted of triarylamine (NAr3) units. The MV radical cation, obtained by chemical oxidation of the triad, exhibited a strong intervalence charge transfer (IVCT) absorption derived from the bis(NAr3)•+ moiety in the near-IR region. The charge-separated MV (CSMV) state, obtained by photoexcitation of the triad, caused a blue shift in IVCT energy in the femtosecond transient absorption spectra, reflecting a bias of positive charge distributions to the D end site. This resulted from increased electron density at the A site and restructuring of the central D site from NAr3 to NAr2 sites. Interestingly, any shift in the IVCT energy that was caused by the polarity of the solvent was minimal, reflecting the unique characteristics of the CSMV state. These findings represent the first detailed analysis of the CSMV state, including a comparison with conventional MV states. Therefore, this work provides new insights into counterion-free MV systems and their applications in molecular devices.

New π-extended catecholato complexes of Pt(ii) and Pd(ii) containing a benzothienobenzothiophene (BTBT) moiety: synthesis, electrochemical behavior and charge transfer properties.

Benzothienobenzothiophene (BTBT) and derivatives have received increasing attention as organic field-effect transistor materials and molecular conductors. This report presents the first synthesis of metal complexes involving a BTBT moiety, which was achieved by complexation of 2,2'-bipyridyl complexes of Pt(ii) and Pd(ii) with dihydroxy-substituted BTBT (1) as a new π-extended catecholato ligand (tBu2Bpy = 4,4'-di-tert-butyl-2,2'-dipyridyl). The resulting complexes M(tBu2Bpy)(O2BTBT) (M = Pt (3Pt) and Pd (3Pd)) were characterized by UV-vis spectroscopy, density functional theory (DFT) calculations, and cyclic voltammetry. The electron donating ability of BTBT was substantially enhanced upon including two oxygen substituents followed by metal coordination. This enabled chemical oxidation of 3Pt and 3Pd with a mild chemical oxidant (ferrocenium hexafluorophosphate) and formation of the one-electron-oxidized state. While 3Pt and 3Pd exhibited an absorption band originating from a catecholate → Bpy ligand-to-ligand charge transfer transition typical of this class of catecholato complexes, the radical cations exhibited a unique π-π* intramolecular charge transfer (ICT) transition absorption in which the π and π* orbitals were the newly incorporated benzothienothiophene-based donor and semiquinonato-based acceptor, respectively. The BTBT+ skeleton was electronically divided into two sites by the present chemical modification. The ICT properties of the complexes were found to be modulated by varying the metal ions. These findings offer a new approach to molecular design for (semi)conducting materials using optical properties.

Multifunctional one-dimensional rhodium(I)-semiquinonato complex: substituent effects on crystal structures and solid-state properties.

Two new one-dimensional (1D) rhodium(I)-semiquinonato complexes formulated as [Rh(3,6-DBSQ-4,5-PDO)(CO)2]∞ (4; 3,6-DBSQ-4,5-PDO(•-) = 3,6-di-tert-butyl-4,5-(1,3-propanedioxy)-1,2-benzosemiquinonato) and [Rh(3,6-DBSQ-4,5-(N,N'-DEN))(CO)2]∞ (5; 3,6-DBSQ-4,5-(N,N'-DEN)(•-) = 3,6-di-tert-butyl-4,5-(N,N'-diethylenediamine)-1,2-benzosemiquinonato) were synthesized to explore the nature of the unusual structural phase transition and magnetic and conductive properties recently reported for [Rh(3,6-DBSQ-4,5-(MeO)2)(CO)2]∞ (3; 3,6-DBSQ-4,5-(MeO)2(•-) = 3,6-di-tert-butyl-4,5-dimethoxy-1,2-benzosemiquinonato). Their crystal structures and magnetic and conductive properties were investigated. Compounds 4 and 5 comprise neutral 1D chains of complex molecules stacked in a staggered arrangement with fairly short average Rh-Rh distances of 3.06 Å for 4 and 3.10 Å for 5. These distances are similar to those for 3 (3.09 Å); however, the molecules of 5 are strongly dimerized in the 1D chain. Compound 4 undergoes a first-order phase transition at Ttrs = 229.1 K, and its magnetic properties drastically change from antiferromagnetic coupling in the room-temperature (RT) phase to strong ferromagnetic coupling in the low-temperature (LT) phase. In addition, compound 4 exhibits a long-range ordering of net magnetic moments originating from the imperfect cancellation of antiferromagnetically coupled spins between the ferromagnetic 1D chains at TN = 10.9 K. Furthermore, this compound exhibits an interesting crossover from a semiconductor with a small activation energy (Ea = 31 meV) in the RT phase to a semiconductor with a large activation energy (Ea = 199 meV) in the LT phase. These behaviors are commonly observed for 3. Alternating current susceptibility measurements of 4, however, revealed a frequency-dependent phenomenon below 5.2 K, which was not observed for 3, thus indicating a slow spin relaxation process that possibly arises from the movements of domain walls. In contrast, compound 5, which possesses a strongly dimerized structure in its 1D chain, shows no sign of strong ferromagnetic interactions and is an insulator, with a resistivity greater than 7 × 10(7) Ω cm.

Decatantalate--the last member of the group 5 decametalate family.

A tetra-n-butylammonium (TBA) salt of [Ta10O28](6-) was synthesized by heating TBA6[H2Ta6O19] in toluene for a prolonged period. X-ray structural analysis of TBA6[Ta10O28]·6H2O revealed that the anion has the decametalate structure and is isostructural with the decavanadate and decaniobate anions [a = 15.8517(8) Å, b = 19.364(1) Å, c = 21.935(1) Å, ß = 93.638(1)°, V = 6719.4(6) Å(3), Z = 2, and space group P2(1)/n at 292(2) K].

A one-dimensional platinum mixed-valence complex with bridging thiocyanate S atoms: [[Pt(II)(en)2](µ-SCN)[Pt(IV)(en)2](µ-SCN)](ClO4)4 (en is ethane-1,2-diamine).

A new one-dimensional platinum mixed-valence complex with nonhalogen bridging ligands, namely catena-poly[[[bis(ethane-1,2-diamine-κ(2)N,N')platinum(II)]-µ-thiocyanato-κ(2)S:S-[bis(ethane-1,2-diamine-κ(2)N,N')platinum(IV)]-µ-thiocyanato-κ(2)S:S] tetrakis(perchlorate)], {[Pt(2)(SCN)(2)(C(2)H(8)N(2))(4)](ClO(4))(4)}(n), has been isolated. The Pt(II) and Pt(IV) atoms are located on centres of inversion and are stacked alternately, linked by the S atoms of the thiocyanate ligands, forming an infinite one-dimensional chain. The Pt(IV)-S and Pt(II)···S distances are 2.3933 (10) and 3.4705 (10) Å, respectively, and the Pt(IV)-S···Pt(II) angle is 171.97 (4)°. The introduction of nonhalogen atoms as bridging ligands in this complex extends the chemical modifications possible for controlling the amplitude of the charge-density wave (CDW) state in one-dimensional mixed-valence complexes. The structure of a discrete Pt(IV) thiocyanate compound, bis(ethane-1,2-diamine-κ(2)N,N')bis(thiocyanato-κS)platinum(IV) bis(perchlorate) 1.5-hydrate, [Pt(SCN)(2)(C(4)H(8)N(2))(2)](ClO(4))(2)·1.5H(2)O, has monoclinic (C2) symmetry. Two S-bound thiocyanate ligands are located in trans positions, with an S-Pt-S angle of 177.56 (3)°.

Long hydrogen-bonded rod of molecular oxide: a hexatantalate tetramer.

A tetra-n-butylammonium (TBA) salt of [H(4.5)(Ta(6)O(19))](3.5-) was synthesized by reacting hydrous tantalum oxide with TBAOH. X-ray structural analysis of TBA(3.5)[H(4.5)(Ta(6)O(19))]·2THF·5.5H(2)O (THF = tetrahydrofuran) revealed that this compound consists of a hydrogen-bonded, rod-shaped tetramer of hexatantalate that is almost 30 Å long together with TBA cations and solvent molecules of crystallization [a = 20.6354(5) Å, b = 25.5951(7) Å, c = 37.2058(8) Å, α = 77.092(1)°, ß = 86.177(1)°, γ = 88.683(1)°, V = 19110.9(8) Å(3), Z = 8, and space group P ̅1]. (1)H NMR spectra showed that this tetrameric structure is maintained in solution.

[Intraoperative, salvaged, autologous blood transfusion in oncologic surgery].

Intraoperative, salvaged, autologous blood transfusions carried out with autotransfusion devices are commonly used for cardiovascular surgery, and also enable the treatment of massive hemorrhage in orthopedic and gynecologic surgeries to prevent potential complications of homologous blood transfusions, such as transmission of infection, immune reactions, and blood type incompatibility. Transfusion of salvaged blood in oncologic surgery may cause hematogenous metastasis and dissemination of malignant tumor cells. However, some investigators have reported that blood irradiation or filtration using leukocyte reduction filters can prevent contamination by malignant tumor cells. Intraoperative autotransfusion with the combination of blood irradiation and leukocyte reduction filters could be therefore a promising technique for the treatment of profuse hemorrhage in oncologic surgery.

[H(x)TeV9O28]((5-x)-) (x=1 and 2): vanadotellurates with decavanadate structure.

Two new vanadotellurates, [HTeV(9)O(28)](4-) and [H(2)TeV(9)O(28)](3-) have been synthesized and structurally characterized as tetra-n-butylammonium (TBA) salts: TBA(4)[HTeV(9)O(28)]·2CH(3)CN [triclinic, space group P ̅1, a = 16.7102(6) Å, b = 17.4680(7) Å, c = 17.9634(7) Å, α = 74.412(1)°, ß = 67.494(1)°, γ = 74.160(2)°, Z = 2] and TBA(3)[H(2)TeV(9)O(28)] [monoclinic, space group P2(1)/c, a = 13.0013(5) Å, b = 19.157(1) Å, c = 28.453(1) Å, ß = 97.222(2)°, Z = 4]. The results of the structural analyses indicate that the four O atoms that bridge two V atoms on the Te side are the most basic ones in the structure. The results of density-functional theory (DFT) calculations support this view.

[Anesthetic management of a Jehovah's Witness for pancreaticoduodenectomy].

For religious reasons, Jehovah's Witnesses do not accept homologous blood transfusions. Instead, they request alternative medical care that does not involve such transfusions. A 58-year-old woman, a Jehovah's Witness, was scheduled for pancreaticoduodenectomy for pancreatic carcinoma under general and epidural anesthesia. She presented with hemoglobin (Hb) concentration of 10.3 g x dl(-1) and hematocrit (Ht) of 31.5% preoperatively. She was fully informed about the risk of cardiac arrest and postoperative complications without blood transfusion, and consented to the bloodless surgery with infusion of colloid solutions; albumin and hydroxyethylated starch, and intraoperative, salvaged, autologous blood transfusion. She submitted a signed letter, absolutely refusing homologous blood transfusion and releasing the hospital from any liability. The general anesthesia was induced using fentanyl, propofol, and vecuronium, and maintained with sevoflurane and vecuronium in combination with epidural anesthesia using lidocaine and fentanyl. An autologous blood transfusion device was prepared for use in the event of massive intraoperative hemorrhage. The pancreaticoduodenectomy and cholecystectomy were performed without the necessity of starting the intraoperative, salvaged, autotransfusion. The volume of intraoperative hemorrhage was 1,108 ml. Lactated Ringer's solution 3,300 ml, physiological saline 200 ml, and hydroxyethylated starch 500 ml were infused during the operation. Although her postoperative Hb and Ht dropped to 8.7 g x dl(-1) and 26.8%, respectively, no transfusion was performed. Anesthesiologists should respect the demands of Jehovah's Witnesses, and should attempt to manage surgery without transfusion.

Polymorphic crystal approach to changing the emission of [AuCl(PPh3)2], analyzed by direct observation of the photoexcited structures by X-ray photocrystallography.

The photoexcited charge-transferred state of [AuCl(PPh(3))(2)] in a novel polymorphic crystal form was directly observed by X-ray photocrystallographic analysis. Its photoexcited state was completely different from the one generated in the known crystal of [AuCl(PPh(3))(2)]; the photoexcited bond-shrunk state was generated in the known crystal. This difference in the generated photoexcited state was clearly reflected by the difference in emission color. While the known crystal form showed green phosphorescence, the novel form showed blue phosphorescence under UV irradiation. The difference in the generated photoexcited state was due to the differences in steric hindrance in the crystal; bond shortening by photoexcitation was sterically allowed in the known form, while on the other hand, it was restricted in the novel form. Therefore, instead of the bond-shrunk state, the charge-transferred excited state became the lowest triplet state, and the emission color changed from green to blue (i.e., a blue shift of the emission wavelength was observed). These results mean that the photoexcited structure and the emission color of [AuCl(PPh(3))(2)] can be controlled by designing the molecular environment in the crystal.

[Efficacy of remifentanil in anesthetic management for living-donor renal transplantation].

BACKGROUND: We used fentanyl and remifentanil in living-donor renal transplantation patients. So, we have compared both drugs in renal function. METHODS: We used the volatile anesthetic sevoflurane as the base in 30 living-donor renal transplantation patients, dividing them into a remifentanil anesthesia group of 15 patients and a fentanyl anesthesia group of 15 patients, and compared their creatinine, BUN, and serum K values before surgery, and 1 day as well as 3 days after surgery. RESULTS: The results showed improvement in their values, and there were no significant differences between the two groups. CONCLUSIONS: Since more patients in the remifentanil group had adequate diuresis beginning immediately postoperatively without taking a diuretic, remifentanil appears to be a more suitable drug to use for anesthesia for living-donor renal transplantation.

Flexibility of cubane-like Cu4I4 framework: temperature dependence of molecular structure and luminescence thermochromism of [Cu4I4(PPh3)4] in two polymorphic crystalline states.

Multitemperature X-ray structure analyses and photoemission spectra of [Cu(4)I(4)(PPh(3))(4)] in two polymorphic crystals reveal that the cubane-like framework is flexibly distorted effecting luminescence thermochromism.

[Drug eruption during living-donor renal transplantation in which it was difficult to identify the causative drug: a case report].

A 59-year-old man with renal failure given oral medication for the symptoms associated with it had no drug allergies before surgery. The patient received 8 units of FFP for a surgery of gastric tumor. The stomach tumor was benign, and living-donor renal transplantation was performed. After the living-donor transplantation, extensive reddening and swelling were observed over the patient's entire body. Anaphylaxis due to drug allergy was considered, and the patient's course was monitored. The flare and swelling tended to regress, and after about 3 hours they were resolved. The following day the drugs used intraoperatively were tested, but it was difficult to identify any allergy-inducing drugs. Ultimately, the FFP was suspected as the cause, and the patient appeared to have been saved by the methylprednisolone used as an immunosuppressive agent.