bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal Decomposition of Silver Amidotriphosphate Ag4P3O9NH2
Authors: Takenaka Atsushi , Motooka Itaru , Nariai Hiroyuki 
Published: July 2006

Abstract
Silver amidotriphosphate Ag4P3O9NH2, was heated at a rate of 5 K min−1 in a stream of dry air, humid air, or dry HCl. When heated to 245 °C in a stream of dry air, Ag4P3O9NH2 was decomposed mainly to oligophosphates with some phosphorus-nitrogen bonds. Condensation of Ag4P3O9NH2 by the action of HCl took place even at room temperature.
Asymmetric Synthesis of Benzoin by SmI2-Mediated Enantioselective Protonation
Authors: Takeuchi Seiji , Miyoshi Norikazu , Hirata Kenji , Hayashida Haruyoshi , Ohgo Yoshiaki 
Published: July 2006

Abstract
Samarium (Z)-1,2-diphenylethen-1,2-diolate, which is considered to be an intermediate of a SmI2-mediated reduction of benzil, was protonated enantioselectively by quinidine to afford (R)-benzoin in 91%ee. It was found that quenching the unreacted enediolate with oxygen was crucial to obtain high enantioselectivity. The configuration of the samarium enediolate was confirmed by isolating (Z)-O,O′-diacetyl-1,2-diphenylethen-1,2-diol.
Synthesis of Soluble Poly(thio-2,6-dimethyl-1,4-phenylene) by Oxidative Polymerization of Bis(3,5-dimethylphenyl) Disulfide
Authors: Jikei Mitsutoshi , Katoh Junya , Sato Naohiko , Yamamoto Kimihisa , Nishide Hiroyuki , Tsuchida Eishun 
Published: July 2006

Abstract
Poly(thio-2,6-dimethyl-1,4-phenylene) has been prepared by the oxidative polymerization of bis(3,5-dimethylphenyl) disulfide. The obtained polymer is amorphous and soluble in common organic solvents. The properties of the polymer are similar to those of poly(oxy-2,6-dimethyl-1,4-phenylene), rather than poly(thio-1,4-phenylene) (PPS). The polymer is obtained as a high molecular weight substance compared with other substituted or non-substituted PPS derivatives by the oxidative polymerization. The polymer containing a disulfide bond, whose structure was confirmed by the reduction of the polymer, acts as an initiator of radical polymerization.
Enantioselectivity in the Interaction of Calf Thymus DNA with Acridine Derivatives Having an Amino Ester or Amino Alcohol Substituent
Authors: Asakawa Masumi , Endo Ken , Kobayashi Kenji , Toi Hiroo , Aoyama Yasuhiro 
Published: July 2006

Abstract
Unless a bulky aromatic side chain is involved, acridine derivatives 1 and 2 having an amino ester or amino alcohol substituent bind to calf thymus DNA via intercalation. The binding constants evaluated by the Scatchard analysis of the hypochromicity data indicate that (1) the substituents introduced are rather inhibitory of the binding and (2) l-enantiomers are preferred than the d-enantiomers by a factor of KL/KD = 1.1–1.4, except for the case of aspartic and glutamic esters where the optical selectivity is very low or even reversed. The present enantioselectivity is discussed in terms of a local C2 chirality of the intercalation site, steric effects of the amino ester or amino alcohol substituents, and a possible conformation-controlling effect of the CO2CH3 or CH2OH group.
Reactions of 2-[(Phenylthio)methylene]tetralin-1-thione
Authors: Moriyama Satoshi , Motoki Shinichi 
Published: July 2006

Abstract
Hetero Diels–Alder reactions of 2-[(phenylthio)methylene]tetralin-1-thione (1) with methyl acrylate, methyl vinyl ketone, acrylonitrile, and other electron-poor dienophiles afford the corresponding cycloadducts (2), from which thiophenol is eliminated by the treatment with sodium alkoxide to give the corresponding 2H-thiopyran derivatives (3). The cycloadducts 2 with styrene and indene do not undergo elimination. The reactions of thioketone 1 with cycloalkenones give both the cycloadducts and the elimination products, even in the absence of a base. The reactions of 1 with acryloyl, crotonoyl, cinnamoyl, and 3-methyl-2-butenoyl chlorides give dienecarbothioic S-esters, in good yields, which are converted into stable dienecarbodithioic esters by the treatment with Lawesson’s reagent. In the reaction of 1 with methyl 2-bromoacrylate, elimination of sulfenyl bromide takes place to afford the elimination product 3.
EXAFS and X-Ray Diffraction Studies on the Structure of the Tetrathiocyanatocadmate(II) Complex in Dimethyl Sulfoxide
Authors: Ozutsumi Kazuhiko , Takamuku Toshiyuki , Ishiguro Shin-ichi , Ohtaki Hitoshi 
Published: July 2006

Abstract
The structure of the tetrathiocyanatocadmate(II) complex in dimethyl sulfoxide (DMSO) has been studied by the EXAFS (extended X-ray absorption fine structure) and solution X-ray diffraction methods. It has been revealed that the tetrathiocyanatocadmate(II) complex has a five-coordinate structure with an additional DMSO molecule. The structure in DMSO is different from that in water and N,N-dimethylformamide, in which no solvent molecule coordinates to the central metal ion. It has also been seen that the coordination mode of the thiocyanate ions in the tetrathiocyanatocadmate(II) complex changes depending on the source of thiocyanate ions due, probably, to different hydrogen bonding abilities of the N- and S-sites of the thiocyanate ion with the counter cations, i.e., the [Cd(NCS)3(SCN)(dmso)]2− and [Cd(NCS)4(dmso)]2− complexes are formed in solutions containing NH4SCN and (C2H5)4NSCN, respectively. The Cd–N, Cd–S, and Cd–O bond lengths within [Cd(NCS)3(SCN)(dmso)]2− are, respectively, 222(1), 262(1), and 234(1) pm, while the Cd–N and Cd–O bond lengths within [Cd(NCS)4(dmso)]2− are 223(1) and 239(2) pm, respectively.
Diastereoisomers of Platinum(II) Complexes with Chiral N-Substituted 1,2-Diamines. II. Structures of Dichloro[(S)-1-(2-amino-2-methylpropyl)amino-2-propanol]platinum(II)
Authors: Saito Reiko , Goto Masafumi , Hirose Junzo , Kidani Yoshinori 
Published: July 2006

Abstract
Square-planar complexes with the formula [PtCl2(S-Hp-Mepn)], where S-Hp-Mepn is (S)-1-(2-amino-2-methylpropyl)amino-2-propanol, CH3CH(OH)CH2NHCH2C(CH3)2NH2, were synthesized and separated into three types of crystals: small imbricate crystals (1), needles (2), and plates (3). 1H NMR spectroscopy has revealed that 1 and 2 are diastereoisomers each other but that 3 consists of both diastereoisomers in 1 : 1 composition. X-Ray crystallography has shown that the diastereoisomer 2 has the absolute configuration of R about the nitrogen atom of secondary amine and 3 is a quasi-racemic compound of S(N) and R(N) isomers: 2; orthorhombic, space group P212121 with a = 10.447(1), b = 13.017(2), c = 8.764(2) Å, R = 0.043, Rw = 0.052: 3; monoclinic, space group C 2 with a = 21.530(1), b = 11.019(2), c = 13.491(5) Å, β = 125.73(1)°, R = 0.042, Rw = 0.054. But the conformations of R(N)-isomers in 2 and 3 were different. The analysis of the CD and 1H NMR spectra of 1 and 2 shows that 1 has the absolute configuration of S about the secondary amine site. For both isomers, the major conformers in aqueous solution are those with equatorially substituted N-hydroxypropyl group and are different from those found in crystals where the packing force participates.
Synthesis of a Polycyclic π-Conjugated System Containing an Azulene Unit by the Flash Vacuum Pyrolytic Method. II. Synthesis and Paratropic Properties of 3H-Cyclopent[a]azulen-3-one and Its Methyl Derivatives
Authors: Kitamori Yoichiro , Yasunami Masafumi , Hioki Takanori , Kikuchi Ikue , Takase Kahei 
Published: July 2006

Abstract
3H-Cyclopent[a]azulen-3-one and two methyl derivalives, which have a new tricyclic π-conjugated system, were synthesized starting from 9-methoxycarbonyl-1,2-dihydro-3H-cyclopent[a]azulen-3-one by the application of flash vacuum pyrolysis in the final step. All proton signals of these compounds were observed at higher fields than those of the referenced 1,2-dihydro compound, but there are no significant differences between the carbon magnetic resonances of 3H-cyclopent[a]azulen-3-ones and the reference compound. These high field shifts on 1H NMR were appreciated in terms of an induced paramagnetic ring current caused by the contribution of a 12-π electron system in the periphery of this molecule. 3H-cyclopent[a]azulen-3-one was stable in the crystalline state, but gradually changed in solution to a hexacyclic compound by decarbonylative dimerization, while the 2-methyl derivative was very stable both in the crystalline state and in solution. Although the reaction of 3H-cyclopent[a]azulen-3-one with cyclopentadiene immediately gave a [4+2] cycloaddition product, the reaction with dimethyl acetylenedicarboxylate gave no products. These chemical behaviors are consistent with the results of Hückel molecular orbital calculations.
Syntheses of Azobenzene Derivatives Having Fluoroalkyl Chain and Their Monomolecular Film Formation at the Air/Water Interface
Authors: Yoshino Norio , Kitamura Mitsuharu , Seto Tsuyoshi , Shibata Yasuhiro , Abe Masahiko , Ogino Keizo 
Published: July 2006

Abstract
The compounds, 4-(nonafluorobutyl)aniline, 4-(tridecafluorohexyl)aniline, and 4-(heptadecafluorooctyl)aniline were prepared by the reaction of corresponding perfluoroalkyl iodide with 4-iodoaniline in the presence of copper bronze. Six azobenzene derivatives (4-(4-fluorophenylazo)phenol, F(C6H4)N=N(C6H4)OH (1) (C6H4 = p-phenylene), 4-(4-trifluoromethylphenylazo)phenol, CF3(C6H4)N=N(C6H4)OH (2), 4-(4-heptafluoropropylphenylazo)phenol, C3F7(C6H4)N=N(C6H4)OH (3), 4-(4-nonafluorobutylphenylazo)phenol, C4F9(C6H4)N=N-(C6H4)OH (4), 4-(4-tridecafluorohexylphenylazo)phenol, C6F13(C6H4)N=N(C6H4)OH (5), and 4-(4-heptadecafluorooctylphenylazo)phenol, C8F17(C6H4)N=N(C6H4)OH (6)) were prepared by the usual diazo coupling reactions using 4-(perfluoroalkyl)aniline and phenol. The monomolecular film formations of the azobenzene derivatives at the air/water interface were investigated by surface pressure measurements to be dependent on the fluoroalkyl chain length (n). The compounds 5 (n = 6) and 6 (n = 8) formed stable monomolecular films at the air/water interface.
Topochemical Studies. XV. Structure of Triclinic Form of the Photodimer of Cinnamamide
Authors: Iwamoto Tetsuyuki , Kashino Setsuo 
Published: July 2006

Abstract
New polymorph of the photodimer of cinnamamide has been found: 2,4-Diphenyl-1,3-cyclobutanedicarboxamide, C18H18N2O2, Mr = 294.16, mp = 553–555 K, triclinic, , a = 8.756(1), b = 16.969(1), c = 5.2499(3) Å, α = 93.104(6), β = 106.514(7), γ = 97.035(8)°, V = 738.9(1) Å3, Z = 2, Dm = 1.32(1), Dx = 1.323 Mg m−3, Cu Kα (λ = 1.54178 Å), μ = 0.71 mm−1, F(000) = 312, T = 295 K, R = 0.045 for 2138 unique reflections with |F0| larger than σ(F0). The crystal structure has close relationship with that of cinnamamide. The structure is also discussed in comparison with that of the monoclinic form of the photodimer.
An Isomeric Series of Thiophene-Fused Tetracyanoquinodimethanes. II. The Crystal and Molecular Structures
Authors: Iwasaki Fujiko , Toyoda Nobuhiko , Hirota Masamichi , Yamazaki Norimasa , Yasui Masanori , Kobayashi Keiji 
Published: July 2006

Abstract
The crystal structures of three isomeric thiophene-fused TCNQs, 4,8-bis(dicyanomethylene)-4,8-dihydrobenzo[1,2-b : 4,5-b′]dithiophene (1), [1,2-b : 5,4-b′] isomer (2), and [1,2-b : 4,5-c′] isomer (3) have been determined by the X-ray method. The crystals of 1, 2, and 3 are an isostructure of the monoclinic system with the space group of P21/n. For 1, a = 16.588(3), b = 7.222(5), c = 11.353(3) Å, β = 89.88(2)°, V = 1360.1(10) Å3, Z = 4, Dx = 1.545 Mg m−3. For 2a = 16.594(4), b = 7.232(2), c = 11.433(2) Å, β = 91.05(2)°, V = 1371.8(5) Å3, Dx = 1.532 Mg m−3. For 3a = 16.738(2), b = 7.342(3), c = 10.922(3) Å, β = 92.98(2)°, V = 1340.4(7) Å3, Dx = 1.568 Mg m−3. These crystals show an orientational disorder with an approximate molecular symmetry of mm. The occupancy factors are 0.834 : 0.166, 0.709 : 0.291, and 0.5 : 0.1 : 0.15 : 0.25 for 1, 2, and 3, respectively. The final R values are 0.065, 0.070, and 0.096 for 2308, 2410, and 1566 observed reflections for 1, 2, and 3, respectively. In the crystals molecules form a sheet-like network perpendicular to the b axis, with short intermolecular S···N distances (3.047 and 3.086 Å for 1 and 3.076 Å for 2). The internetwork distances between S atoms are significantly shorter than the van der Waals contact: 3.451 and 3.461 Å for 1 and 2, respectively. Each molecule has a butterfly shape. Two dicyanomethylene groups are bent from the quinonoid ring to the same side and two thiophene rings are bent to the opposite side of the dicyanomethylene groups.
An Isomeric Series of Thiophene-Fused Tetracyanoquinodimethanes. III. Crystal Structures of Charge-Transfer Complexes with TTF
Authors: Iwasaki Fujiko , Hironaka Shinji , Yamazaki Norimasa , Kobayashi Keiji 
Published: July 2006

Abstract
The crystal structures of the charge-transfer complexes of two isomeric thiophene-fused TCNQs, 4,8-bis(dicyanomethylene)-4,8-dihydrobenzo[1,2-b : 4,5-b′]dithiophene (1), and [1,2-b : 4,5-c′] isomer (3) with tetrathiafulvalene (TTF) have been determined by the X-ray method. For 1–TTF, triclinic, , a = 10.458(2), b = 9.852(2), c = 11.292(8) Å, α = 92.60(7), β = 113.64(6), γ = 97.38(6)°, V = 1051(2) Å3, Z = 2, Dx = 1.646 Mg m−3. For 3–TTF, triclinic, , a = 9.059(2), b = 8.459(2), c = 8.850(2) Å, α = 103.36(2), β = 115.76(2), γ = 106.30(2)°, V = 535.1(3) Å3, Z = 1, Dx = 1.616 Mg m−3. The final R values are 0.079 for 3437 observed reflections and 0.048 for 1937 observed reflections for 1–TTF and 3–TTF, respectively. The crystal structure of 1–TTF complex is composed of TTF pairs and TCNQ pairs. These pairs stack alternately with each other. The mean distances between molecular planes are: 3.62 Å for TTF–TTF, 3.49 Å for 1–1 and 3.36 Å for 1–TTF. In the crystals of 3–TTF the molecules form mixed stacks with the separation of 3.59 Å. The molecular geometry of TTF in the 1–TTF complex shows a TTF+ character, while that in 3–TTF shows a neutral type.
Transfer of Electronic Excitation Energy from 2,2-Diphenylethanol to 2,6-Diphenylpyridine in Solvents of Different Viscosity
Authors: Jana Pallabi , Mallik Gautam Kumar , Ganguly Tapan , Banerjee Sukhendu Bikash 
Published: July 2006

Abstract
Measurement of emission spectra indicates that in diluted solution of 2,2-diphenylethanol (DPE)–2,6-diphenylpyridine (DPP) system in solvents of different viscosity, the rate parameters kxy associated with nonradiative energy transfer from donor X (DPE) to acceptor Y (DPP) decrease with increasing viscosity of the medium. Further kxy values are higher than diffusion controlled rates kd. The Förster critical transfer distance R0 is much greater than the sum of the radii of the donor and acceptor, rx+ry. The observations seemingly indicate that energy-transfer from donor DPE to acceptor DPP mainly occurs by coulombic interaction over the dipole–dipole interaction distance which exceeds the molecular dimensions. In the DPE–DPP system, there is no evidence of external quenching.
Preparation of 1,2,3-Naphthalenetriamine, 1,2,5,6- and 1,2,7,8-Naphthalenetetramine, and 5,6,7,8-Quinolinetetramine and -Isoquinolinetetramine by Reduction of the Fused 1,2,5-Thiadiazole Ring
Authors: Mataka Shuntaro , Ikezaki Youji , Takahashi Kazufumi , Tori-i Akiyoshi , Tashiro Masashi 
Published: July 2006

Abstract
The two fused 1,2,5-thiadiazole-rings of naphthalenes 1a and 1b, quinoline 2a, and isoquinoline 2b were reduced with tin and concentrated hydrochloric acid in refluxing dioxane, giving the expected 1,2,5,6-naphthalenetetramine (4a) and 1,2,7,8-tetramine derivative 4b, 5,6,7,8-quinolinetetramine (15a) and isoquinoline analogue 15b in moderate yields. Partially reduced diamine 5 was formed as a by-product in the reduction of 1a. The expected 1,2,3,4-naphthalenetetramine (4c) was not obtained in the reduction of 1c at room temperature and the 1,2,3-triamine 8 was formed in 27% yield. The intermediary formation of 4c was confirmed by acetylating the crude reduction mixture of 1c, giving tetraacetyl derivative 11. The reduction of naphthotris[1,2,5]thiadiazole 3 afforded 4,5-diamine 16 in 44% yield. Polyamines 4a–b, 8, 15a–b, and 16, were obtained as their hydrochloride(s).
Synthetic Study on Peptide Antibiotic Nisin. V. Total Synthesis of Nisin
Authors: Fukase Koichi , Kitazawa Manabu , Sano Akihiko , Shimbo Kuniaki , Horimoto Shingo , Fujita Hiroshi , Kubo Akira , Wakamiya Tateaki , Shiba Tetsuo 
Published: July 2006

Abstract
Total synthesis of a lanthionine peptide nisin was achieved by the successive condensations of four segments including cyclic lanthionine peptide parts and the C-terminal linear segment including dehydroalanine, followed by the deprotection procedure with anhydrous HF. Modified reaction conditions for the Hofmann degradation were applied to prepare the dehydroalanine residue from the 2,3-diaminopropionic acid residue. The final deprotection with anhydrous HF proceeded without decomposition of the dehydroamino acid residues which are generally labile in acidic media. The synthetic nisin was completely identical with the natural one in all respects, resulting in a confirmation of the proposed structure.
Oxidative Coupling of Methane over Various Barium Salts Mixed with CaO: The Relation with Their Surface Basicities
Authors: Yamagata Nobutsugu , Nakamura Kazuyoshi , Kimura Satoshi , Sasaki Shouich , Yamada Misako , Okazaki Susumu 
Published: July 2006

Abstract
Oxidative coupling of methane to ethane and ethylene was carried out over barium salts mixed with CaO catalysts prepared by a wet-mixing method. The mixing effect of the barium salts on the C2 yield at 800 °C was remarkable in the following order: BaBr2 &gt; BaCl2 &gt;&gt; BaI2, Ba(OH)2, BaF2 &gt; BaC2O4, Ba(NO3)2 &gt; BaCO3, BaSO4 &gt; Ba3(PO4)2( &gt; CaO). The high C2 yield of the BaCl2/CaO catalysts was kept relatively long, and was nearly constant (19–20%) over a range of 5 to 30 mol% BaCl2. Measurements of the temperature-programmed desorption of the used barium salt/CaO catalysts showed that a catalyst with the high C2 selectivity and high C2 yield tended to have large CO2 desorption peaks at higher temperatures; they were also well-dispersed with barium ions. In the case of BaCl2/CaO catalysts (2.5–40 mol% BaCl2), a large desorption peak of CO2 was observed at around 730 °C, that was associated with their high C2 yields. The role of basic sites resulting from the desorption of CO2 is discussed.
Molecular Motions in Solid CD3NH3PbBr3 as Studied by 1H NMR
Authors: Xu Qiang , Eguchi Taro , Nakayama Hirokazu 
Published: July 2006

Abstract
The temperature dependence of the 1H spin-lattice relaxation times (T1) was measured through the successive phase transitions in solid CD3NH3PbBr3. The T1’s in the lowest-temperature phase (phase-III) have a single minimum at 30 K, indicating that CD3NH3+ undergoes a correlated C3-reorientation (Ea= 2.7 kJ mol−1) about the C–N axis. This fact clearly supports the previous assignment of the relaxation mechanism near 65 K in phase-III of CH3NH3PbBr3, where an uncorrelated C3-reorientation of the cations is excited (Ea= 7.5 kJ mol−1).
AM1 Potential Energy Curves for Cis–Trans Isomerization of Stilbene Cation Radicals
Authors: Kikuchi Osamu , Oshiyama Tomohiro , Takahashi Ohgi , Tokumaru Katsumi 
Published: July 2006

Abstract
AM1 potential energy curves of stilbene cation radical and its derivatives were calculated by the open-shell RHF methods as a function of the twist angle of the central C–C bond. The electronic properties of the potential energy curves of stilbene cation radicals were well understood, and the substitutent effect on the barrier height for the cis-trans isomerization was evaluated.
Synthesis and Photo Valence Isomerization of Polyamide Bearing Norbornadiene Unit
Authors: Kamogawa Hiroyoshi , Gochou Seigo , Nakahara Masatsugu 
Published: July 2006

Abstract
Polyamides bearing norbornadiene (NBD) unit were prepared by the reaction of either bis(p-nitrophenyl) 2,3-NBD-dicarboxylate or a mixed anhydride bearing at the NBD moiety with various diamines. Films made of the polyamides indicated reversible UV-spectrum changes with UV irradiation, suggesting the occurrence of the photo-valence isomerization between the NBD and quadricyclane units.
High Polariton Reflectance in Heptamethinebis(dimethylamino)cyanine Chloride Crystal
Authors: Daehne Lars , Kamiya Koji , Tanaka Jiro 
Published: July 2006

Abstract
The reflection spectra of single crystals of bis(dimethylamino)heptamethinium chloride were measured with polarized light in the region from 500 to 38000 cm−1. The Kramers Kronig transformation was calculated and the determined dielectric functions are discussed in terms of the polariton and molecular exciton theories. The highly anisotropic reflection band is caused by one narrow molecular transition, which is polarized parallel to the molecular chain. The bathochromic shift of the transition energy compared to the value in solution and the large splitting of transverse and longitudinal modes are explained by the molecular exciton theory. The expected charge resonance transition could not be found. That will be discussed in respect to the arrangement of the molecules in the crystal.
Thermodynamic Studies on the Complexation of o-Phenylenediamine-N,N,N′,N′-tetraacetate with Divalent Cadmium, Mercury, and Lead Ions in Aqueous Solutions
Authors: Azuma Shigeki , Nakasuka Noriyuki , Tanaka Motoharu 
Published: July 2006

Abstract
Potentiometric studies have been carried out on the complexation of o-phenylenediamine-N,N,N′,N′-tetraacetate (phdta, L4−) with the cadmium and lead ions (M2+) in aqueous solutions at 25 ± 0.1 °C and I = 1.00 M (NaClO4). The ligand buffer method was successfully applied to the determination of the formation constant (M2+ + L4− = ML2− : KML) by use of Cd and Pb ion-selective electrodes. This method gave log KML = 13.37 for CdL and 13.89 for PbL. Calorimetry and potentiometry gave the values of enthalpy and entropy of complexation (−ΔH°/ kJ mol−1 = 18.9, ΔS°/J K−1 mol−1 = 193 (CdL); 34.8, 149 (PbL); and 50.6, 165 (HgL), respectively). Thermodynamic parameters of the protonation to ML were also examined for the PhDTA complexes of these and some divalent transition metal ions. The metal complexes are classified into two categories according to the thermodynamic parameters: A) Mn2+, Cd2+, and Pb2+ (−ΔH°MHL = −1.1–1.1 kJ mol−1; ΔS°MHL = 43–49 J K−1 mol−1). B) Co2+, Ni2+, Cu2+, and Zn2+ (−ΔH°MHL = 8.0–11.3 kJ mol−1; ΔS°MHL = 18–37 J K−1 mol−1). The smaller value of −ΔH°MHL for A has been interpreted in terms of simple protonation to a carboxylate oxygen in the complex ML, with any acetate group not being dissociated. The entire process of protonation for B, however, may be composed of two steps: i) Detachment of one carboxylate group from the metal ion, followed by the hydration resulting in M(L′) (H2O)2−, where L′ represents a ligand anion with a free carboxylate group, ii) Protonation to an oxygen atom of the detached carboxylate group.
Analysis of Ortho Effects with a Steric Parameter Defined by the Acidic Hydrolysis Rate of Ortho-Substituted Benzamides
Authors: Sotomatsu Tomoko , Fujita Toshio 
Published: July 2006

Abstract
The applicability of our new steric parameter for ortho substituents, Es(AMD), in evaluation of organic reactivity and physicochemical data was examined. The Es(AMD) constant was derived from the rate constants for acidic hydrolysis of ortho-substituted benzamides, and its scale was put as close as possible to that of the Es steric parameter of Taft, and Kutter and Hansch (TKH). For alkyl and halogen substituents, the Es(AMD) value was very close to the TKH Es value, but for methoxyl, isopropoxyl, and such planar π-bonded substituents as NO2 and Ph, it was not. Reactivity and physicochemical data taken from the literature were analyzed quantitatively by use of steric and electronic parameters, and the results obtained by Es(AMD) and Es were compared. The Es(AMD) value gave better results than TKH Es in various reactions including those of benzoic acids and their derivatives, if the change in the hybridization geometry of the reaction center between the initial and intermediate states was similar to that of the reference reaction.