bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constituents of Roots of Rubia Lanceolata Hayata
Authors: Kuo Su‐Ching , Chen Pey‐Rin , Lee Shwu‐Woan , Chen Zong‐Tsi 
Published: May 2015

AbstractA naphthohydroquinone and eight anthraquinones were isolated from the roots of Rubia lanceolata Hayata. Their structures were assigned as mollugin (1), l‐hydroxy‐2‐methyl‐9,10‐anthraquinone (2), 2‐methylquinizarin (3), 3‐carbomethoxy‐l‐hydroxy‐9,10‐anthraquinone (4), lucidin ethyl ether (5), rubiadin (6), alizarin (7), ω‐hydroxypachybasin (8) and digiferruginol (9) on the basis of spectral evidence. Among them, compounds 8 and 9 were isolated for the first time from Rubia species.
Theoretical Calculations of Combination of Hydrogen Atoms
Authors: Shyu Jiann‐Shing 
Published: May 2015

AbstractA resonance‐complex set was developed to investigate the process of combination of hydrogen atoms with a modified resonance‐complex theory and Monte‐Carlo trajectory method over the temperature range 40‐300 K. The obtained ratios of ortho to para at 300 K and at 77 K agree satisfactorily with experimental results. Unlike previous results, a maximum of the rate coefficient as a function of temperature is found near 150 K.
Synthesis of N‐ (1, 3‐Dimethyl‐1 H‐2, 3‐Dihydrobenzimidazol‐2‐Ylidene) Acetamido Derivatives as Potential Antiarrhythmic Agents
Authors: Al‐Khamees Hamad A. 
Published: May 2015

AbstractN‐(1,3‐dimethyl‐1H‐2,3‐dihydrobenzimidazol‐2‐y]idene)‐acetamido derivatives were prepared and evaluated for antiarrhythmic activity.
Metal Ion Dependent Binding and Nuclease Activity of Hexaazacyclophane
Authors: Chang Tsu Hsin , Ong Chi Wi , Chou Yi Meen , Chuang Kuo‐Shen , Wang Wen Jwu 
Published: May 2015

AbstractThe HAPP‐Fe complex was more active than HAPP‐Cu complex in cleavage of DNA in the presence of dithiothreitol and hydrogen peroxide. In contrast, the HAPP‐Cu complex was found to bind more strongly with λ‐DNA, whereas the HAPP‐Fe binds weakly. It was shown that the metal ion complexed with HAPP ligand can influence the binding and cleaving activity due to the ability of the ligand to undergo geometrical tautomerization.
Chemistry of Isodrin Derivatives. The Syntheses of 11‐ and 12‐Hydroxy‐1,4,4a,9,9a,10‐Hexahydro‐Endo, Endo‐1,4;9,10‐Dimethano‐Anthracenes
Authors: Chow Tahsin J. 
Published: May 2015

AbstractThe titled compounds are synthesized through multi‐step sequences involving consecutive [n4s + n2s] cycloadditions of norbornadiene with two units of chlorinated cyclopentadiene. A dyotropic double hydrogen migration was observed between two closely located double bonds during the process of aromatization of a cyclohexadiene moiety. A hydroxyl group is introduced onto either of the two methylene bridges in order to provide products suitable for solvolytic analyses.
Optical Nonlinearities of Phthalocyanines and Naphthalocyanines
Authors: Wen Tsai‐Chuan , Jen Shiaw‐Juang , Liu Huei‐Wen , Hwang Long‐Chih , Lian Iu‐De 
Published: May 2015

AbstractThe nonlinear absorption and refraction of soluble phthalocyanines and naphthalocyanines have been measured with z‐scan technique using 8 ns, 532 nm laser pulses. The excited‐state absorption cross‐section and the excited‐state refractive‐index cross section have been estimated under the consideration of laser induced thermal effect. The excited state absorption induced n2 and Re χ(3) values are in the range of 10−12 esu. These observed data are enhanced by the concentrations of both metal substituted Pc's and Nc's, but this increment became very small for the metal free phthalocyanine. During the optical limiting experiments, a 25% linear transmitted solution of R8PcH2 can limit laser pulses to ≤ 120 μJ from incident energies as high as 2.0 mJ, and this limitation moved down to ≤ 50 μJ when replacing R8PcCu from P8PcH2. A similar property has also been observed for the metal substituted naphthalocyanines. The results indicate that both the nonlinear refraction and optical limiting properties should be strongly affected by the metal induced triplet‐state nonlinear absorption in both Pc's and Nc's. Moreover, the laser pulses created a self trapped filament inside the solution of this optical limiter, while emitting time‐resolved, concentric rings on a projection screen, which could be induced by the thermal lensing effect. The various optical nonlinear properties observed from these materials should make them valuable as an optical limiter.
Aminolysis of N‐acyl‐2‐Oxazolidinones with Primary Arylamines
Authors: Wu Ming‐Jung , Tseng Tsung‐Chin 
Published: May 2015

AbstractThe reaction of N‐acyl‐2‐oxazolidinones with aniline and analogs in the presence of 1.1 equiv of T1Cl4 gave the corresponding amides in modest to high yields.
Stereoselectivity of the Diels‐Alder Reaction of (E)‐γ‐Oxo‐α,β‐Unsaturated Thioesters with Cyclopentadiene
Authors: Tsai Shih‐Hwa , Chung Wen‐Sheng , Wu Hsien‐Jen 
Published: May 2015

AbstractThe stereoselectivity of the Diels‐Alder reaction of (E)‐γ‐oxo‐α,β‐unsaturated thioesters 3a‐3d with cyclopentadiene is greatly enhanced in the presence of Lewis acids favoring the endo acyl isomers 4a‐4d. In the absence of Lewis acid, Diels‐Alder reaction of 3a‐3d with cyclopentadiene at 25 °C gave two adducts 4a‐4d and 5a‐5d in a ratio of 1:1 respectively. In the presence of Lewis acids, Diels‐Alder reaction of 3a‐3d with cyclopentadiene gave 4a‐4d and 5a‐5d in ratios of 75‐94:25‐6 respectively. The stereoelectivity was enhanced to ratios of 95‐98:5‐2 with lowering the reaction temperature. The stereochemistry of the cycloadducts 4 and 5 was confirmed by iodocyclization. Reaction of the endo‐thioester 5c with I2 in aqueous THF at 0 °C gave the novel methylthio group rearranged product 6c in 80% yield, the first example of iodo‐lactonization of endo‐thioesters. Reaction of the endo‐acyl isomer 4b with I2 under the same reaction conditions gave an isomeric mixture of 7b and 8b in 1:2 ratio. The stereochemistry of the thioester group in 8b was proved by X‐ray single‐crystal analysis. The solvent effect on the endo selectivity of (Z)‐γ‐oxo‐α,β‐unsaturated thioester 2b was also examined.
Dissociation Kinetics of Nickel (II), Zinc (II) and Cadmium (II) Complexes of 1,7‐Diaza‐4,10,13‐trioxacyclopentadecane‐N,N′‐diacetic Acid and 1,10‐Diaza‐4,7,13,16‐tetraoxacyclooctadecane‐N,N′‐diacetic Acid
Authors: Chang C. Allen 
Published: May 2015

AbstractThe dissociation kinetics of the complexes of nickel(II), zinc(II) and cadmium(II) of 1,7‐diaza‐4,10,13‐trioxacyclopentadecane‐N,N′‐diacetic acid (K21DA) and 1,10‐diaza‐4,7,13,16‐tetraoxacyclooctadecane‐N,N′‐diacetic Acid (K22DA) were studied in constant ionic strength aqueous medium with various [H+]‐range, i.e., (0.88−53.9) × 10−5 M and (0.5−7.5) × 10−3 M. Copper(II) was used as the scavenger of free ligand and the rates of dissociation of these complexes have been found to be independent of (Cu2+]. All the complexes exhibit acid‐independent and acid‐dependent pathways. For NiK21DA, CdK21DA and CdK22DA complexes, the acid‐dependent rates are linear functions of [H+]. For NiK22DA and ZnK21DA complexes, a saturation kinetics is observed, i.e., [H+]‐dependence at low [H+] and [H+]‐independent at high [H+]. The rationalization of such different observations is proposed to be due to difference in complex solution structures rather than the thermodynamic stabilities. Influence of acetate content in the buffer, temperature, and total electrolyte concentration on the rate of dissociation has also been investigated and discussed.
Three Prenylated Isoflavones from Erythrina variegate
Authors: Huang Keh‐Feng , Yen Yuh‐Fang 
Published: May 2015

AbstractTwo new prenylated isoflavones (erythrivarones A and B) were isolated from the stem bark of Erythrina variegata Linn, together with the known compound alpinumisoflavone (1). The structures of erythrivarones A and B were characterized as dihydroalpinumisoflavone (2) and 4′‐hydroxy‐[6″,6″‐dimethyldihydropyrano(2″,3″:5,6)]‐[6‴,6‴‐dimethyldihydropyrano(2‴,3‴:7,8)]isoflavone (3), respectively, by means of spectroscopic analysis.
Bromination of Binor‐S
Authors: Chow Tahsin J. , Chen Yi‐Lung , Lin Kuan‐Jiuh , Wang Yu‐Wen , Li Chun‐Lien 
Published: May 2015

AbstractBromination of binor‐S resulted in a mixture of products containing several pairs of isomers. Three major processes were found to be involved in the reaction mechanism, i.e., bromination, hydrobromination, and dehydrobromination. The structures of nine compounds derived from dibromide 6 were identified by spectroscopic methods. Yields between isomers were rationalized by comparison of their relative strain energies calculated by force field model (MM2). The crystal structures of a tribromide (9) and a pentabromide (15) were solved by X‐ray diffraction analyses. Their crystal packing patterns indicated the existence of attractive interactions among the bromine atoms.
Total Synthesis of (±)‐Patriscabrol and (±)‐Boschnialactone
Authors: Chiu Jiun‐Yuh , Chiu Chih‐Tsao , Chang Nein‐Chen 
Published: May 2015

AbstractA total synthesis of (±)‐patriscabrol (1) and (±)‐boschnialactone (2) is described. The cyclopentapyranone skeleton is assembled by means of Baeyer‐Villiger oxidation of ketol 5.
Satellite Hole Investigation of the Vibrational Modes of 9‐Aminoacridine upon Binding to DNA
Authors: Cheng Ji‐Yen , Chiang Chien‐Chih , Cheng Yah‐Ru , Chen Hsuan‐Shen , Lin Leh‐Jame , Chang Ta‐Chau 
Published: May 2015

AbstractThe spectral features of satellite holes are used to investigate 9‐aminoacridine‐DNA interactions. The hole depths of the outer ring vibronic modes are reduced more than that of the inner ring vibronic modes, implying that inner ring motion is less perturbed than outer ring motion. As a result, the mode coupling between the inner ring and outer ring is reduced upon binding to DNA. However, similar hole frequency and width of the satellite hole corresponding to the NH2 mode upon binding to DNA imply that the amino group of 9‐aminoacridine sits outside the DNA.
A New Approach to the Synthesis of Cortical Steroids
Authors: Shih Ing‐Lung , Hendrickson James B. 
Published: May 2015

AbstractA new bondset for cortical steroid synthesis is developed from the dual concepts of convergent assembly and multiple construction. A short synthesis on this bondset is presented in which the final bond construction by electrocyclization took an unwanted course. Stereocontrol is discussed separately.
Enantioseparation of Reduced Haloperidol by Capillary Zone Electrophoresis with Dimethyl‐β‐Cyclodextrin
Authors: Wu Hsin‐Lung , Wu Shou‐Mei , Chen Su‐Hwei , Otsuka Koji , Terabe Shigeru 
Published: May 2015

AbstractChiral separation of reduced haloperidol (RHP), an optically active metabolite from haloperidol, by capillary electrophoresis is described. RHP was separated on an uncoated capillary with dimethyl‐β‐cyclodextrin (dimethyl‐β‐CD) in Tris phosphate buffer using PEG 6000 as an organic additive. Several parameters affecting the separation of RHP were studied, including pH and concentration of buffer, buffer additive, and concentration of chiral selector. The migration order of the resolved RHP was assigned with reference RHP enantiomers.
Natural Product Chemistry: From Plants to Human
Authors: Tsai Ming‐Daw 
Published: May 2015

AbstractConventionally, natural product chemistry deals with the isolation, characterization, and synthesis of compounds from plants. It a broad sense, natural product chemistry may include all fields of biochemistry. Two projects are presented to illustrate the expanded definition of natural product chemistry. One deals with phosphatidylinositol (PI) and the key enzyme involved in its metabolism, PI‐specific phospholipase C. The other project is on the structure‐function relationship of human tumor suppressor p16.
EPR Studies of Photoreduction of Ni/TiO2 Catalysts
Authors: Chien Shu‐Hua , Wei Yu‐Wen , Lin Mau‐Chen 
Published: May 2015

AbstractIrradiations of Ni/TiO2 catalyst by UV in hydrogen at 77 K produced not only Ni+ ions on the catalyst surface, but also Ni3+ and Ti3+ species in bulk or near the interface between nickel and titania. These photo‐generated species were detected and characterized by low temperature electron paramagnetic resonance (EPR) spectroscopy. Relative spin concentrations of the photogenerated paramagnetic species (Nin+ and Ti3+) varied with the nickel content in titania. A high nickel content in the sample resulted in a high peak intensity ratio of Nin+ to Ti3+. It was found that the photoinduced self‐redox reaction of Ni2+ ions to form Ni+ and Ni3+ ions has a priority over the photoreduction of Ti4+ to Ti3+ ions. The characteristic EPR spectrum of the Ni3+ (3d7) ions with g1 = 2.268, g2 = 2.237, and g3 = 2.045 indicates that the Ni3+ ions are most likely located in the substitutional sites of TiO2, possibly near the surface rutile phase. The Ni+ species (3d9) with g4 = 2.130 and g1 = 2.063 are on the surface of TiO2. Both Ni+ and Ni3+ ions are quite stable in hydrogen. The Ni3+ ions seem to be responsible for anchoring the nickel ions onto titania and stablizing the Ni+ species on the surface. The Ni+ ions are thus free from oxygen poisoning and still show a high activity toward olefin oligomerization.
Mechanistic Studies on the Photogenerated Dienol with α‐Phenyl‐N‐tert‐Butylnitrones
Authors: Pan Kai , Ho Tong‐Ing 
Published: May 2015

AbstractThe mechanism for the photochemical reactions of o‐methyl‐benzaldehyde (1), o‐methyl‐acetophenone (2) and o‐methyl‐benzophenone (3) in the presence of α‐phenyl‐N‐tert‐butylnitrone (PBN) to the formation of stable nitroxyl radicals 4–6 is studied.The nitroxyl radical product 6 can also be obtained by the thermolysis of benzocyclobutenol with PBN. Thus, the radical products were derived from a novel and regioselective 4+2 cycloaddition of the photogenerated dienol intermediate with PBN.
Synthesis and Properties of 3‐Thia‐9‐azabicyclo[3.3.1]nonan‐7‐one
Authors: Ho Tse‐Lok , Lin Yueh‐Jyh 
Published: May 2015

AbstractN‐Benzyl‐3‐thia‐9‐aza‐bicyclo[3.3.1]nonan‐7‐one has been prepared from methyl 4‐bromocrotonate by reaction sequence involving sodium sulfide, benzylamine, and Dieckmann condensation. Some spectral and chemical properties of this system are also reported.
One‐Pot Formation of Carbonates from the Reactions of Carbonyl Compounds with Samarium Diiodide and Methyl Chloroformate
Authors: Lu Ling , Fang Jim‐Min , Lee Gene‐Hsiang , Wang Yu 
Published: May 2015

AbstractTreatment of carbonyl compounds with SmI2 and methyl chloroformate in the presence of molecular sieves provides the cyclic carbonates or biscarbonates of pinacols. This one‐pot reaction proceeds rapidly even with aliphatic ketones. The stereochemistry obtained by this procedure is different from that of conventional pinacolic couplings.
A Convenient Halogenation Procedure for the Preparation of α‐Halocarbonyl Compounds
Authors: Cheng Sheng‐Fan , Lin Ching‐Shan , Liu Lilian Kao 
Published: May 2015

AbstractExcept for substituted acetophenones (p‐Y‐C6H4COCH3, Y=H, Br, CH3O), simple ketones, β‐ketoesters and 1,3‐diketones reacted smoothly with a preformed homogeneous mixture of hydrochloric acid and potassium permanganate in acetonitrile to give moderate to good yields of the corresponding α‐chlorocarbonyl compounds. Mixtures of α‐chloro‐ and α,α‐dichlorocarbonyl compounds were obtained for substituted acetophenones. Brominations proceeded similarly with higher yields when the hydrochloric acid was replaced with hydrobromic acid.
Immobilized Aspergillus Oryzae Protease Catalyzed Formation of Peptide Bonds in Organic Solvent
Authors: Shih Ing‐Lung , Lin Yun‐Yin , Huang Hui‐Yao , Tai Dar‐Fu , Chen Kuan‐Chu 
Published: May 2015

AbstractImmobilized Aspergillus oryzae protease (AOP) catalyzed the formation of peptide bonds between TV‐protected amino acids and amino acid esters or amides in ethyl acetate. The influences of pH and reaction time on the coupling of Boc‐L‐Tyr and Gly‐NH2 were studied. The optimal reaction condition for this enzyme catalyzed synthesis of Boc‐L‐Phe‐Gly‐NH2 (98.66%) was at pH 5.5 and a duration of 48 hours.
Protein Engineering III: Computer Aided Design of Disulfide‐Bond Free Cobra Venom Cardiotoxin with a Novel Conformation and Biological Activity from Synthetic Peptides
Authors: Chen Shui‐Tein , Yang Maw‐Tsiung , Wu Sung‐Yang , Wang Kung‐Tsung 
Published: May 2015

AbstractUsing the crystal structure of cobra venom cardiotoxin as a templet, a computer designed peptide with a novel conformation and biological activity has been synthesized chemically. The designed peptide utilized two calcium coordination sites instead of disulfide bridges to hold the conformation. The coordination sites were introduced at the cleft of three β‐sheet strands by replacing the residues of Leu‐1, Leu‐26, Ser‐28, Leu‐48, and Ser‐55 with Glu and using their γ‐carboxyl groups as legends. The residues of Cys at positions 3, 14, 21, 38, 42, 53, 54, and 59 of the four disulfide bridges were changed with Gly to remove all the disulfide bonds. Circular dichroism spectra showed that the synthesized peptide has a conformation similar to that of the native cardiotoxin of a defined structure only in aqueous solutions with the presence of calcium ions. Immunoprecipitation assay, using the anti‐cardiotoxin V, showed that in the presence of calcium ion the peptide had same cross reaction as that of native cardiotoxin. Hemolysis assay in the presence of calcium ion (150–250 mmol) and phospholipase A2 showed that the peptide had 65–70% as much cytolytic activity as the native toxin.
Structural Characterization of Venom Toxins by Physical Methods and the Perspectives on Structure‐Function Correlation of Proteins
Authors: Chiou Shyh‐Horng , Wu Shih‐Hsiung 
Published: May 2015

AbstractThis account describes work in our laboratories on the application of physical methods to the structural studies of various toxins during the past few years. A general review of background and the meaningful results obtained from these approaches are described. The results are compared with updated information on related subjects carried out at other laboratories. Examples of structural studies on some small toxins present abundantly in Formosan cobra (Naja naja atra), one of the indigenous toxic snakes in Taiwan, are given with the emphasis on the identification and characterization of complex toxic protein components based on near‐infrared Fourier transform Raman Spectroscopy. We will also describe our initial efforts in solving the solution structures of several small proteins and peptides by means of two‐dimensional nuclear magnetic resonance (2D‐NMR) and computer‐simulated modeling. The structural information obtained by these modem physical techniques provides the framework for unraveling the complex structure‐activity relationships engendered by these biomolecules.
Nucleophilic Addition Reactions of Tricarbonyl [η5−1‐(Phenylsulfonyl)cyclohexadienyl]iron(I) Complex
Authors: Chou Shang‐Shing P. , Hsu Chien‐Hung 
Published: May 2015

AbstractHydride abstraction of tricarbonyl[η4‐1‐(phenylsulfonyl)‐1,3‐cyclohexadiene]iron(0) complex 2 with Ph3C+PF6− regiospecifically provided the title compound 3 in excellent yield. Cationic complex 3 could react with a variety of nucleophiles in good yields. Soft nucleophiles prefer to attack at the C‐5 position, whereas hard nucleophiles such as methyllithium and the enolate of ethyl acetate gave the C‐5 as well as the C‐2 addition products. Some synthetic applications of the addition products were also studied.
Kaurane‐Type Diterpenoids from Liverworts
Authors: Liu Huei‐Ju , Tseng Shu‐Huey , Wu Jen‐Dar , Wu Chia‐Li 
Published: May 2015

AbstractSeven kaurane‐type diterpenoids were isolated from the Taiwanese liverworts Jungermannia truncata. Among them, three are new structures. They are: ent‐16‐kauren‐3, 15‐dione (6), ent‐16(S)‐kauran‐3,15‐dione (7), and ent‐14α‐hydroxy‐16‐kauren‐15‐one (11). From Plagiochila pulcherrima, three known kaurane alcohols were also isolated along with sesquiterpenoids plagiochilines A, B, C and ent‐4β, 10α‐dihydroxyaromadendrane.
Effects on Coordination of Thioether Sites. 4. Structural Analysis of η3‐Tripodal Ligand Manganese(I) Complexes
Authors: Wang Hsin‐Ell , Huang Chi‐Tsuan , Yiin Lih‐Ming , Cheng Ming‐Chu , Peng Shie‐Ming , Liu Shiuh‐Tzung 
Published: May 2015

AbstractCrystal structures of a series of manganese(I) complexes containing tripodal ligands were determined. For [η3‐{CH3C(CH2PPh2)2(CH2SPh)‐P,P′,S}Mn(CO)3]PF6 (1): a = 10.856(3) Å, b = 19.698(3) Å, c = 17.596(5) Å, β = 96.17(2)°, monoclinic, Z = 4, P21/c, R(Fo) = 0.068, Rw(Fo) = 0.055 for 3617 reflections with Io > 2σ(Io). For [η3‐{CH3C(CH2PPh2)(CH2SPh)2‐P,P′,S}Mn(CO)3]PF6 (2): a = 9.890(2) Å, b = 20.403(4) Å, c = 10.269(3) Å, β = 117.44(2)°, monoclinic, Z = 2, P2l, R(Fo) = 0.050, Rw(Fo) = 0.037 for 1760 reflections with Io > 2σ(Io). For [η3‐{CH3C(CH2PPh2)2(CH2S)‐P,P′,S}Mn(CO)3] (4): a = 8.191(7) Å, b = 10.495(3) Å, c = 19.858(6) Å, α = 99.61(2)°, β = 96.17(2)°, γ = 92.70(4)°, triclinic, Z = 2, P‐I, R(Fo) = 0.048, Rw(Fo) = 0.039 for 2973 reflections with Io > 2σ(Io). There is no significant difference in the bond lengths of Mn‐S bonds among three species in their crystal structures [2.325(2) Å in 1; 2.358(4) in 2; 2.380(2) in 4], but the better donating ability of thiolate in complex 4 appears on the lower frequencies of its carbonyl stretching absorptions.
Strong Antiferromagnetic Exchange Interactions in Cobalt(II) Complexes with 2‐Pyridyl Substituted Nitronyl Nitroxide Ligand
Authors: Huang Chian‐Feng , Wei Ho‐Hsiang 
Published: May 2015

AbstractThree new complexes, [Co(hfac)2(NIToPy)] (1), [CoCl2(NIToPy)2] (2), and [Co(NIToPy)3](ClO4)2 (3), with NIToPy = 2‐(2‐Pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐oxy‐3‐oxide, and hfac = hexafluoroacetylacetonate, have been synthesized. The compound 3 crystallized in the monoclinic space group P21, with two molecules in a unit cell of dimensions a = 10.565(4) Å, b = 14.714(9) Å, c = 14.596(7) Å, and β = 107.10(4)°. The temperature‐dependent magnetic susceptibility measurements (4.2 K‐300 K) for the complexes demonstrated strong antiferromagnetic exchange interaction between cobalt(II) ion and NIToPy radical spins with J = −140.1 cm−1 for 1, J = −94.2 cm−1 for 2, and J = −161.8 cm−1 for 3, respectively. The magneto‐structural correlation in these complexes has been discussed.
Crystal Structure of the Coordinatively Unsaturated 2‐Pyridylphosphine Pd(0) Complex Pd(PPh2Py)3
Authors: Su Chi‐Hung , Chiang Michael Y. 
Published: May 2015

AbstractThe three‐coordinate tris(2‐pyridylphosphine)palladium(0) complex is the first example of a group 10 metal complex bearing pyridine substituted phosphine ligand, whose crystal structure is determined. Pd(PPh2py)3 crystallizes in the triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document}, with a = 12.874(4) Å, b = 14.162(3) Å, c = 14.912(3) Å, α = 87.76(2)°, β = 66.50(2)°, γ = 63.17(2)°, Z = 2, and V = 2191(1) Å3. Full‐matrix least‐squares refinement of 523 variables using 4911 data (F2o > 3σF2o) gave R = 0.033 and Rw = 0.033. The pyridine ring is disordered. Possible weak interactions among Ph rings or Py rings and Pd center are discussed. Close approach of the ortho hydrogen on phenyl rings to the Pd center may imply facile ortho metallation.
Orbital Interaction and the Mulliken‐Walsh Diagram for AH2 Systems
Authors: Chen Erh‐Hao , Chang Tse‐Chiang 
Published: May 2015

AbstractWe define θ‐ (or R‐) bonding (or antibonding) character of the molecular orbitals according to the slopes of the orbital energy curves when the internuclear angle (or internuclear distance) is varied. So far the slope of the orbital curve has only been accounted for by the qualitative argument based on two factors: the orbital overlap and the s‐p mixing.We employ the bond orbitals instead of the usual atomic orbitals as the basis set to analysis the character of the molecular orbitals. The Fock matrix in the bond orbital basis can then quantitatively account for the effects of both the overlap and s‐p mixing factors.Our analysis also show that a third factor, the orbital interaction, is essential to account for both the “typical” and “abnormal” behavior of the slopes.