Preparation and Catalysis of a Tri‐coordinated Copper(I) Complex with Bulky P˜N Ligand

Coordination of a bulky pyridinyl‐phosphine ( P?N ) ligand toward CuBr was investigated. However, this P?N donor behaves as a monodentate via the coordination of phosphine to form a bromide bridged dimeric [( P?N )Cu(μ‐Br)₂Cu( P?N )], which was characterized by spectral and crystal structural analysis. It appeared that the “PCu(μ‐Br)₂CuP” unit is planar with a short distance between Cu…Cu' [2.7585(9) Å]. The catalytic activity on Sonogashira coupling of phenylacetylene with aryl halides was studied.     

Chirality Control of Quadruple Helixes of Metal Strings by Peripheral Chiral Ligands

Chirality control of helixes with the Δ (P) or Λ (M) form is interesting in various fields such as extended metal atom chains (EMACs), in which the metal backbones are helically wrapped by four ligands. Herein, we report two EMACs, Δ‐[Ni₅((?)camnpda)₄] and Λ‐[Ni₅((+)camnpda)₄], whose chiralities are controlled by chiral ligands with naphthyridine and camphorsulfonyl groups. There is a large energy difference (108 kcal mol^?1) between the two helical structures with one chiral ligand. Furthermore, the electron communication between [Ni₂]³⁺ units is more pronounced than in [Ni₅(bna)₄Cl₂]²⁺ (bna=binaphthyridylamido). The results demonstrate control of small‐scale helical structure and set the stage for future development of chiral controlled base and nanoelectronic devices.     

Chemotaxonomy of Triterpenoid Pattern of HPLC of Ganoderma lucidum and Ganoderma tsugae

Three strains of Ganoderma tsugae (CCRC36065, CCRC37034, CCRC37038) and three strains of Ganoderma lucidum (CCRC36021, CCRC37029, CCRC37033) were cultivated. Their triterpenoid patterns of the fruit body were analyzed by reverse phase HPLC using a gradient elution of acetonitrile/2% acetic acid (1/4 and 1/2). The triterpenoid patterns of G. tsugae and G. lucidum are different. But similar 2 and 3 dimensional patterns are obtained among three strains of G. tsugae. Different patterns are found among different strains of G. lucidum. Ganoderic acid A( 1 ), B( 2 ), C( 3 ) and D( 4 ) were isolated from the ethanol extract of G. tsugae.     

Reactivity of Iminophosphoranes. Formation of the Piperazine Ring

Reaction of 3-azidopropyl methanesulfonate with triphenylphosphine produced the 1,4-bis(triphenyl-phosphino)piperazine 5 by intermolecular cyclization, instead of formation azidine derivatives by an intramolecular pathway. Structural formulation of 5 was achieved by both spectral and X-ray crystal analysis. Hydrolysis of 5 under basic condition gives piperazine, whereas reaction of lithium diphenylphosphide with 5 produced 1,2-bis(diphenyl-phosphino)ethane (dppe) exclusively.     

Mutation of isoleucine 705 of the oxidosqualene-lanosterol cyclase from Saccharomyces cerevisiae affects lanosterol's C/D-ring cyclization and 17α/β-exocyclic side chain stereochemistry

Site-saturated substitution in Saccharomyces cerevisiae oxidosqualene-lanosterol cyclase at Ile705 position produced three chair-boat-chair (C-B-C) truncated tricyclic compounds, two 17α-exocyclic protosteryl intermediates, two protosteryl C-17 truncated rearranged intermediates and the normal biosynthetic product, lanosterol. These results indicated the importance of the Ile705 residue in affecting lanosterol's C/D ring stabilization including 6-6-5 tricyclic and protosteryl C-17 cations and 17α/β-exocyclic side chain stereochemistry.     

Carbene-based ruthenium photosensitizers

A new series of N-heterocyclic carbene (NHC)-pyridine ruthenium complexes incorporating a carbene unit as an ancillary ligand were designed and successfully synthesized by using simple synthetic methods. The photophysical, electrochemical and photovoltaic properties of these NHC-pyridine based ruthenium complexes were investigated. These complexes showed photoelectric conversion efficiencies in the range of 6.43 ～ 7.24% under the illumination of AM 1.5 (100 mW cm(-2)). Interestingly, the modifications on the ancillary ligand of these sensitizers by removal of an alkoxyl group and replacement of the octyl chain with a 3,5-difluorobenzyl group showed a 13% increase in the conversion efficiency for the CifPR dye. These results demonstrated that structural modifications on the NHC-pyridine ancillary ligand of ruthenium complexes results in dye-sensitized solar cells exhibiting a comparable cell performance to that obtained using the standard N719 dye.     

Determination of displacement with a piezoelectric transducer using phase-shift algorithms

This investigation accurately measures the relationship between applied voltage and the displacement of a piezoelectric transducer device both by analyzing phase shifting interferometry algorithms and using a Twyman-Green interferometer. Simulations are performed to calculate unknown phase shifts, especially around π/2 and 3π/2. It is indicated that the Hariharan algorithm is indeed an effective phase shifting interferometry algorithm.     

Haemoglobin immobilized on nafion modified multi-walled carbon nanotubes for O2, H2O2 and CCl3COOH sensors

A conductive biocomposite film (MWCNTs-NF-Hb) containing multi-walled carbon nanotubes (MWCNTs) incorporated with entrapped haemoglobin (Hb) in nafion (NF) has been synthesized on glassy carbon electrode (GCE), gold (Au), indium tin oxide (ITO) and screen printed carbon electrode (SPCE) separately by potentiostatic methods. The presence of both MWCNTs and NF in the biocomposite film enhances the surface coverage concentration (Γ), and increases the electron transfer rate constant (K_s) to 132%. The biocomposite film exhibits a promising enhanced electrocatalytic activity towards the reduction of O₂, H₂O₂ and CCl₃COOH. The cyclic voltammetry has been used for the measurement of electrocatalysis results of analytes by means of biocomposite film-modified GCEs. The MWCNTs-NF-Hb-modified GCEs’ sensitivity values are higher than the values obtained for other film modified GCEs. The surface morphology of the biocomposite films which have been deposited on ITO has been studied using scanning electron microscopy and atomic force microscopy. The studies have revealed that there was an incorporation of NF and immobilization of Hb on MWCNTs. Finally, the flow injection analysis has been used for the amperometric studies of analytes at MWCNTs-Hb and MWCNTs-NF-Hb film modified SPCEs. The amperometric study results have shown higher slope values for MWCNTs-NF-Hb biocomposite film.     

Revisit of trinickel metal string complexes [Ni3L4X2] (L = dipyridylamido,diazaphenoxazine; X = NCS,CN) for quantum transport

Metal string complexes contain a linear metal‐atom chain in which the metal centers are coordinated by four equatorial and two axial ligands. With a variety of transition‐metal elements and ligands, the structural framework drives the flourishing of molecular design and properties. The one‐dimensional configuration makes the compounds suitable for the studies of quantum transport across molecular junctions. In this study, we report the conductance measurements and transmission spectra of three trinickel metal strings, [Ni₃(dpa)₄(NCS)₂] ( 1 ), [Ni₃(dzp)₄(NCS)₂] ( 2 ), and [Ni₃(dpa)₄(CN)₂] ( 3 ) (Hdpa = dipyridylamine, Hdzp, diazaphenoxazine) in which 1 is a prototypical compound, dzp of 2 represents an equatorial ligand more rigid than dpa of 1 , and ─CN is an axial ligand with a ligand‐field effect stronger than ─NCS of 1 . Measurement results of molecular junctions for 1 , 2 , and 3 are 2.69, 3.24, and 17.4 MΩ, respectively. The highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO–LUMO) gaps calculated by density functional theory in the gas phase for 1 , 2 , and 3 are about 2.65, 2.34, and 3.85 eV, respectively. Zero‐bias transmission spectra of 1 – 3 show that transmission peaks lie just above E_Fermi (the Fermi energy of the gold electrode), suggesting LUMO‐dominant transport pathways. The transmission peaks at E_Fermi are associated with LUMO+2 found in the gas phase. LUMOs in the free space are located at nearly 1 eV below E_Fermi. The shift of molecular orbitals from their isolated form and the alignment of LUMO+2 with the electrode Fermi level manifest the importance and significant of the electrodes' self‐energy on electron transport.     

Cyclic [2]Catenane Dimers,Trimers, and Tetramers

Dimeric, trimeric, and tetrameric cyclic [2]catenanes have been prepared directly through one‐pot sodium‐ion‐templated dynamic imine formation from a diamine and a tetraaldehyde. NaBH₄ mediated reduction of the labile imino bonds of these cyclic [2]catenane oligomers, followed by methylation of the resulting secondary amino groups enabled the isolation and characterization of oligomeric cyclic [2]catenanes as stable, covalently linked compounds.