Masakazu Kita

• Okayama University

Specialized science, technology, engineering, and mathematics (STEM) high schools provide intensive learning experiences for advanced learners. At the core of these STEM, schools are a project-based (research) curriculum that aims to foster research culture among learners, creating critical thinkers and problem-solvers, preparing them to be globall...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

Currently the term “standard electrode potentials” and the detailed descriptions about electrochemical systems appear in all chemistry textbooks for upper secondary school. Half of in-service teachers did not learn this concept when they were upper secondary school students and university students, so they need suitable teaching materials to teach...

This research revealed that metal ions with different charges could significantly affect the viscosity of aqueous sodium carboxylmethylcellulose (CMC) solution. On the basis of an Ostwald viscometer, an improvised apparatus using a dropping ball for examining the viscosity of liquids/solutions has been developed. The results indicate that the collo...

This study investigates Cambodian student competencies in chemistry at lower secondary level by using the TIMSS 2011 standards. 3014 Cambodian students in eighth grade of lower secondary school participated in this research. Their results were compared with the achievement of students from Japan, Thailand, Malaysia and Indonesia on the same TIMSS i...

The precise measurement of conductivity of a semiconductor film such as polypyrrole (Ppy) should be carried out by the four-point probe method; however, this is difficult for classroom application. This article describes the development of a new, convenient, handmade conductivity device from inexpensive materials that can measure the conductivity o...

This paper describes the development of a simple handmade conductivity measurement apparatus based on a Kohlrausch bridge with inexpensive materials. We have examined the reliability of this apparatus with standard solutions and then measured juices of vegetables and fruits as well as a sports drink. Comparisons to total alkali content as determine...

Scavenging rate constants of eight hydrophilic antioxidants, including caffeic acid, chlorogenic acid, genistein, glutathione, N-acetylcysteine, rutin, trolox, and uric acid against multiple ROS, namely superoxide anion, hydroxyl radical, singlet oxygen, and alkoxyl radical were determined with the electron spin resonance method. Direct flash photo...

A series of cobalt(III) complexes containing 2-cyanoethylphosphines, [Co(acac)2{P(CH2CH2CN)nPh3–n}2]BF4 {acac = 2,4-pentanedionate; n = 1 (1), 2 (2), and 3 (3)} have been prepared, and their molecular and crystal structures have been determined. The X-ray diffraction study revealed that these complexes are the trans isomers in the crystals. The Co–...

New iron(III) and cobalt(III) complexes, [Fe(2,2′-dpdtc)3], [Fe(3,3′-dpdtc)3], [Co(2,2′-dpdtc)3], and [Co(3,3′-dpdtc)3] (dpdtc = dipicolyldithiocarbamate) have been synthesized and their molecular structures and spectroscopic properties determined. The 2,2′- and 3,3′-dpdtc ligands have four donors, S, S′, N, and N′. These complexes are insoluble in...

The surface tension of aqueous solution of sodium dodecyl sulfate (SDS) stayed constant by an addition of alpha-, beta-, or gamma-cyclodextrin (CD) since the 1:2 inclusion compound, SDS-2CDs, is formed. On the other hand, the addition of [Co(NH3)(6)](ClO4)(3) into an aqueous solution of the above inclusion compound shows the characteristic drawing...

The presence of NO can be detected by circular dichroism (CD) spectroscopy, which is based on an asymmetric transformation in tris(dithiocarbamato)iron(II) complex. The complex [Fe(S-proOHdtc)3]4− {S-proOHdtc2− = 1-dithiocarboxyl-4-hydroxy-S-proline(2−)} in methanol shows a large negative CD peak at 600 nm. It suggests that, in the epimerization eq...

X-ray crystallographic analyses revealed that the Pd–P and Pd–X bond lengths of [PdX2(P–P)] complexes (X− = Cl, Br and I and P–P = Ph2P(CH2)nPPh2; n = 1: dppm, 2: dppe, 3: dppp, 4: dppb) are: Pd–P (dppm, dppe) < Pd–P (dppp, dppb) and Pd–X (dppm, dppe) > Pd–X (dppp, dppb). The oxidation potentials values, E½(ox), of the shorter Pd–P and longer Pd–X...

A series of cobalt(III) complexes containing 2-cyanoethylphosphines, [Co(Me 2dtc) 2{P(CH 2CH 2CN) nPh 3-n} 2]BF 4{Me 2dtc -: N,N-dimethyldithiocarbamate; n = 1 (1), 2 (2), and 3 (3)} have been prepared, and their molecular structures in the crystals and in solution have been characterized. X-ray analysis revealed that all complexes isolated as sing...

New metal complexes with N,N-diacetatodithiocarbamate (Ac(2)dtc(3)), Na-6[Co(Ac(2)dtc)(3)], Ba-3[Co(Ac(2)dtc)(3)], Na-4[Ni(Ac(2)dtc)(2)], Ba-2[Ni(Ac(2)dtc)(2)], Na-4[Cu(Ac(2)dtc)(2)] and Ba-2[Cu(Ac(2)dtc)(2)], have been synthesized, and their molecular structures and spectroscopic properties have been characterized. The X-ray analysis of Ba-3[Co(Ac...

This study was a mixed quantitative–qualitative research to evaluate the efficacy of a designed student-centred instructional (DSCI) program for teaching about acids and bases. The teaching innovation was designed based on constructivist, hands-on inquiry and context-based approaches and implemented in seven 45-min lessons with a class of 36 grade...

Nitric oxide (NO)-scavenging capacities of several hydrophilic antioxidants were determined by using the PTIO method, a competitive NO-scavenging method with 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO). Relative NO-scavenging rates of antioxidants were measured with respect to PTIO and the scavenging rate constants were calculated...

This study investigated Indonesian and Japanese senior high-school students’ understanding of electrochemistry concepts.SampleThe questionnaire was administered to 244 Indonesian and 189 Japanese public senior high-school students.Design and methodsAn 18-item multiple-choice questionnaire relating to five conceptual categories (reactions occurring...

This study investigated Indonesian and Japanese students’ understandings of macroscopic and submicroscopic levels of representing matter and its changes and the difficulties they have with these concepts. A multiple-choice questionnaire was constructed and delivered to 447 Indonesian and 446 Japanese public senior high school students. The data wer...

Surface tension of anionic surfactant solutions, sodium dodecyl sulfate (SDS) or sodium dodecylbenzenesulfonate (SBS) decreases remarkably in the presence of [Co(NH3)6]X3 (2.50 mM) (X− = Cl−, Br−, I−, or ClO4−) at 298 K, depending on the kind of counter anion X−. The magnitude of reduction is in the order ClO4− ≥ I− > Br− > Cl− for SDS solutions an...

In the new course of study in 2008 in Japan, one of the purpose is to improve the science and the mathematics education. Students need to get not only a lot of knowledge, but also apply to daily life and society. For example, most students know "Ice float on water." "Why does ice float on water?" Many students can answer that ice is lower density t...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

It has been observed that, at 25.0+/-0.1 degrees C, [Co(NH(3))(6)](ClO(4))(3), [Co(en)(3)](ClO(4))(3), [Co(bpy)(3)](ClO(4))(3), and [Co(phen)(3)](ClO(4))(3) in the regions of 1.25-5.00 mM aqueous solutions cause a significant surface tension reduction (STR) of water by the surfactants, sodium dodecylsulfate (SDS) and sodium dodecylbenzenesulfonate...

A simple method of analyzing detergent concentration in water was introduced to upper level high school students. The method used an acrylic fabric in dye solutions containing different detergent concentrations. The color depth of the dyed fabric was determined using a reflection photometer. After the experiment, students were able to determine det...

This article describes a novel, hands-on method to qualitatively determine the extent of microbial activity in topsoil using ordinary blank paper. Appropriate and scalable for the high school and college level, these experiments expose students to some of the challenges facing environmental researchers and also contribute to curriculum development...

A new modified method was applied to the determination of chloride anion in brackish water by using a common copper(II) sulfate solution and a spectrophotometer. The result of the quantitative analysis demonstrated that chloride concentrations were 1.61% w/v and 1.74% w/v at ebb tide and flood tide, respectively, of the Muya River. On the other han...

Novel cobalt(III) complexes containing three kinds of assembled ligands, L1L2=dapymt–tbba(2-), tbba–dapymt(1-) and apymt–tbba(1-) (H3tbba=thiobarbituric acid; Hdapymt=4,6-diamino-2-thiouracil; Hapymt=4-amino-2-thiouracil), were prepared from the mixed ligand systems, where L2 indicates the coordinated ligand to the Co(III) ion and L1 is a pendant...

Four palladium(II) complexes [PdX2(L-N,S)] (X = Cl, Br; L: BzSq = benzyl 8-quinolyl sulfide, PheneSq = phenethyl 8-quinolyl sulfide) were prepared. The crystal structure of [PdCl2(BzSq-N,S)] revealed the presence of an intraligand stacking between the phenyl and quinolyl groups of BzSq. This stacking interaction was confirmed even in Me2SO, MeCN an...

A series of mixed cobalt(III) complexes [Co(pySe)3−n(NN)n]n+ [pySe=pyridine-2-selenolato (1−); NN=1,2-ethanediamine (en) and 2,2′-bipyridine (bpy); n=0, 1 and 2] was prepared. The geometrical preference and trans influence of pySe are fairly different from those of pyridine-2-thiolate. These selenolato complexes were oxidized by peracetic acid to...

The focus of much teacher professional development in South Africa is either on content knowledge or teaching approaches. We believe that equally important are teachers' professional attitudes. Recently Japan has begun to support cooperative development projects in South Africa. In addition to doing very well in international tests of maths and sci...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

Two optically-active O,O′-dialkyl dithiophosphate ligands, (Bor)2PS2− and (Men)2PS2−, were prepared from P2S5 and the monoterpene alcohols, d-borneol and l-menthol. The chromium(III) complexes, [Cr{(Bor)2PS2}3] and [Cr{(Men)2PS2}3], were prepared by reaction with Cr(NO3)3·9H2O in acetone. The diastereoisomers (Δ and Λ) were separated by fractional...

A rapid reversible inversion (epimerization) between the Δ-(R,R,R) and Λ-(R,R,R) diastereomers for fac-Δ- and Λ-tris(R-cysteinato-N,S)cobaltate(III) occurs at room temperature in an aqueous solution of each salt. The half-lives for the mutarotation were measured (k = kΛ + kΔ): 80 and 6 minutes at 20 and 40 °C, respectively. The equilibrium constant...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

Reactions of trans-[Co(acac)2(PPh4)2]PF6 (aca = pentane-2,4-dionate) with PR3 (R = Me or Et) in methanol afforded new complexes, trans-(PPh4) [Co(acac)2(CN)2] and trans-[Co(acac)2(PR3)2]PF6, respectively. The structures of the new trans-isomers, together with those of the corresponding known cis-isomers, were determined by single-crystal X-ray diff...

The H2O2 oxidation of [Co(pyt)(en)2]2+ [1, pyt=2-pyridinethiolate(1−) ion, en=ethylenediamine] afforded the orange [Co(pyse-N,S)(en)2]2+ [2, pyse=2-pyridinesulfenate(1−) ion] complex. Irradiation of this orange complex in the solid state yielded a green complex. The molecular structure of the green complex perchlorate was determined by X-ray diffra...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

Reduction () and oxidation potentials () of [Co(acac)2(L)]+ (acac = 2,4-pentanedionate) complexes containing an NN, NN′, N′N′, NP, PP, NAs, or AsAs′ didentate ligand as L(N = −CH2NH2; N′ = −CH2NMe2; P = −CH2PMe2; As = −CH2AsMe2; As′ = −CH2CH2AsMe2) were determined by electrochemical measurements. The values which reflect the orbital (homo) e...

A stable sulfonato complex, (2-aminoethanesulfonato-N,O)bis(ethylenediamine-N,N′)cobalt(III) perchlorate, [Co(C2H6NO3S)(C2H8N 2)2](ClO4)2, was prepared by oxidation of [Co{OS(O)CH2CH2NH2-N,O}(en)2] 2+ (en = NH2CH2CH2NH2) in acid media. This sulfonato complex was resolved by SP-Sephadex column chromatography and the absolute configuration of the slo...

Twelve new cobalt(III) complexes containing a tetradentate phosphine ligand of the type MeS(CH 2 ) 2 PPh(CH 2 ) n PPh(CH 2 ) 2 SMe (n = 2 L 1 or 3 L 2 ) were prepared. Their structures were assigned on the basis of electronic absorption and 1 H NMR spectra and the molecular structures of cis-α-[CoCl 2 {rac(P)-L 1 }]BF 4 and trans-[CoCl 2 {meso(P...

A stable sulfonato complex, [Co{OS(O)2CH2CH2NH2-O,N}(en) 2]2+, was prepared upon oxidation of [Co{OS(O)-CH2CH2NH2-O,N} (en)2]2+ in acid media. This sulfonato complex was resolved by SP-Sephadex column chromatography (eluent: 0.1 mol dm-3 Na2[Sb2{(+)-tartrate}2]). The absolute configuration of the slower eluted (-)589-isomer was determined to be Δ b...

The reaction of tetramethylthiuram disulfide with a methanol solution containing CoCl2·6H2O and 4,6-diphenyl-4,6-diphosphanonane-1,9-diamine (313NPPN) gave complexes of [Co(dtc)2{rac(P)- or meso(P)-313HNPPNH}]3+ (313HNPPNH = diprotonated form of 313NPPN, dtc = dimethyldithiocarbamate ion). The crystal structure of the perchlorate salt of the meso(P...

An air and thermally stable iron(II) complex of 1,1,1-tris(dimethylphosphinomethyl)ethane (mmtp), [Fe(mmtp)2](BF4)2·2H2O, has been prepared, and the crystal structure has been determined by X-ray analysis. The complex was crystallized in the orthorhombic, space group Pca21 with four molecules in a unit cell of dimensions a = 17.448(4), b = 17.574(4...

N,N-Dimethyl-2-X-thiobenzamide [XCl (abbreviated as Hcbt) and Br (Hbbt)] and N,N-dimethyl-2-(2-bromophenyl) thioacetamide (Hbpt) were cyclopalladated at one of the N-methyl groups upon reaction with lithium tetrachloroparalladate(II), while oxidative addition took place at the aryl-halogen bond of Hbbt, Hbpt and N,N-dimethyl-2-iodothiobenzamide (H...

The crystal structures of trans-[Co(acac)2(PMePh2)2]PF6 (acac = 2,4-pentanedionate ion) (1), trans-[Co(acac)2(H2O)(PMePh2)]ClO4 (2), and trans(P,P)-[Co(acac)(CN)2(PMePh2)2] (3) were determined by the X-ray diffraction method. Complex 1 crystallizes in the monoclinic, space group P2/n, with two molecules in a unit cell of dimensions a = 17.151(2), b...

N,N,N,N-Tetramethylisophthalthioamide (Hmpt) was cyclopalladated with PdCl2 in hot dimethylsulphoxide to give [PdCl(mpt)]. The structure was determined by X-ray analysis. The thioamide is metallated at C(2) to act as an S528-01C528-02S tridentate anionic ligand. There is appreciable steric repulsion between the benzene ring H(4, 6) and the dimethyl...

The crystal structures of trans-[CoCl2(dmpe)2]ClO4 (dmpe = 1,2-bis(dimethylphosphino)ethane) (1), trans(Cl,Cl)cis(P,P)-[CoCl2(edmp)2]PF6·0.5CH3OH (edmp = (2-aminoethyl)dimethylphosphine) (2) and trans-[CoCl2(en)2]NO3 (en = 1,2-ethanediamine) (3) were determined by the single-crystal X-ray diffraction method. Crystal data and final R values are: for...

The crystal structures of [CoCl3 (mmtp)] (mmtp = 1,1,1-tris(dimethylphosphinomethyl)ethane) (complex 1) and [Co(CN)3(mmtp)].2H2O (complex 2) were determined by the single-crystal X-ray diffraction method. Crystal data and final R values are; for complex 1, orthorhombic, P2(1)nb (c, a, b setting of Pna2(1)), a = 13.545(1), b = 13.875(1), c = 9.315(1...

The reaction of the sodium salt of pyrrole with N,N-dimethylthiocarbamoyl chloride in N,N-dimethylformamide gave N,N-dimethylpyrrole-1-carbothioamide (Hnpt), while the reaction of pyrrole with N,N-dimethylthiocarbamoyl chloride under phase transfer conditions afforded N,N-dimethylpyrrole-2-carbothioamide (Hapt), together with a very small amount of...

A method was developed for one-pot synthesis of N,N,N',N'-tetramethylferrocene-1,1'-dicarbothioamide (H(2)fdt); ferrocene was lithiated with n-butyl lithium and then treated with N,N-dimethylthiocarbamoyl chloride. The structure of H(2)fdt was confirmed by X-ray analysis. The H(2)fdt molecule had a twofold axis and the two thioamide groups were nea...

The reaction of elemental sulfur S8 with [Co(dmpe)2](BF4)2 in a mixture of methanol and benzene gave a novel SS-coordinated disulfur oxide cobalt(III) complex, [CO(S2O-S,S')(dmpe)2]ClO4 (1), and a dimethyldithiophosphinato complex, [CO(S2PMe2)2(dmpe)]BF4 (2). The molecular structures of these complexes were determined by X-ray structure analyses. C...

The structures of [Co(acac)2{(CH3)2XCH2CH2NH2}]ClO4 (acac = 2,4–pentanedionate ion, X = N (complex 1), P (complex 2), and As (complex 3)) with a series of group 15 donor atoms were determined by the single-crystal X-ray diffraction method. Crystal data and final R values are: for 1, orthorhombic, Pba2, a = 13.192(2), b = 25.504(5), c = 11.840(2) Å,...

2-Thienylamine (Hata) and 2-furfurylamine (Hafa) reacted with bis(acetylacetonato)palladium(II) [Pd(acac)2] in dichloromethane at room temperature to give Pd(acac)2(Hata) and Pd(acac)2(Hafa), respectively. In refluxing toluene the former amine gave [Pd(acac)(ata)]2, while with the latter no further reaction took place. In Pd(acac)2(Hata) and Pd(aca...

Eleven new cobalt(III)–phosphite complexes of the [Co(S-S)P4]2+- and [Co(S-S)2P2]+-types were prepared, where S-S denotes bidentate dimethyldithiocarbamate (dtc), diethyldithiocarbamate (etdtc), and piperidyldithiocarbamate (pipdtc) ions, and P is 4-ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane (etpb), trimethyl phosphite (pome), and triethyl ph...

N,N-Dimethylthiophene-2- and -3-carboselenoamides, abbreviated as Hats and Hbts, respectively, were easily obtained by the reaction of the corresponding carboxamide with phenyldichlorophosphine selenide. Hats and Hbts reacted with lithium tetrachloropalladate in methanol to give [PdCl(ats)]2 and [PdCl(bts)]2, respectively. Several derivatives of th...

The [Co(dtc)3-n(dmope)n]n+ (n=1, 2) complexes were prepared, where dtc and dmope denote a dimethyldithiocarbamate ion and 1,2-bis(dimethoxyphosphino)ethane, respectively. The absorption and magnetic circular dichroism (MCD) spectra, and reduction and oxidation potentials were compared with those of the corresponding 1,2-bis(dimethylphosphino)ethane...

Eight new cobalt(III) complexes of the type, [CoX3(mmtP)]n+ (mmtp=1,1,1-tris(dimethylphosphinomethyl)ethane, X3=(Cl)3, (Br)3, (CN)3, (NH3)3, mmtp, 3-azapentane-1,5-diamine (dien), 1,4,7-triazacyclononane (tacn), and 1,4,7-trithiacyclononane (ttcn)), were prepared and characterized. All of the complexes are stable in the solid state, but the halogen...

Four new complexes, [Co(acac or dtc)2(dppf or dmpf)]X (X = BF4, B(C6H5)4) have been prepared and characterized by absorption and 1H NMR spectra, and electrochemical measurements. The [Co(acac)2(dppf)]+ complex exhibits the first d-d band at much lower energy than that of [Co(acac)2(dppe)]+ (dppe = 1,2-bis(diphenylphosphino)ethane), while the other...

Bis{2-(dimethylphosphino)ethane-1-thiolato} complexes Ni(II), Pd(II), and Pt(II) were newly prepared, and the molecular structure of the Ni(II) complex was determined by X-ray analysis to have a square planar trans(P,P) geometrical configuration. The 1H, 13C, and 31P NMR spectra of the complexes in CDCl3 indicate a trans(P,P) structure for the nick...

Crystal structures of Pd(I) and Pt(I) dinuclear complexes, [MM'Cl2(mu-Me2Ppy)2] (MM'=Pd2 (1), PdPt (2), and Pt2 (3)) and [Pd2Cl2(mu-Ph2Ppy)2](4), were determined by the single crystal X-ray diffraction method. Crystal data and final R values are: 1, triclinic, P1BAR, a=10.019(2), b=10.902(2), c=9.062(1) angstrom, alpha=97.75(2), beta=102.45(2), gam...

Δ-RR,Λ-SS-[Co(acac)2(rac(P)-L]+ and [Co(acac)2(meso(P)-L)]+ were obtained by reaction of [Co(acac)3] (acac=2,4-pentanedionate ion) with 5,8-diphenyl-5,8-diphospha-2,11-dithiadodecane (L) in 1 : 1 molar ratio in dichloromethane in the presence of active charcoal, no Δ-SS,Λ-RR isomer of the rac(P)-L complex being formed. Five-coordinate [Ni(rac(P)-L)...

A new tetraaza-macrocyclic complex involving a ten-membered chelate ring, trans-[Co(NO2)2(N410)]BF4(N410=1,4,7,10-tetraazacycloheptadecane) was prepared and the structure was determined by the X-ray diffraction method. The ten-membered chelate ring takes a distorted boat–chairboat form with the N–Co–N bite angle of 105.4(1)°.

The electronic spectra of trans-[CoCl2(NH3)4]Cl and its analogues measured in the solid state at 113 K show four ligand field bands assignable to the Ia(1Eg(a)<--1A1g), Ib(1A2g<--1A1g), IIa(1B2g<--1A1g), and IIb(1Eg(b)<--1A1g) transitions in D4h approximation. The ligand field parameters obtained from the observed data are; e-sigma(N) = 7400-8000 c...

The complexes [MX2(PMe2py-P)2] (M=Pd(II), Pt(II); X=Cl, Br, and I) have been synthesized and characterized both in the solid state and in solution by their infrared and 1H, 13C, and 31P NMR spectra, in addition to an X-ray crystallographic analysis of cis-[PdCl2(PMe2py-P)2]. The latter complex exists as a cis–trans equilibrium mixture in solution,...

Twelve new cobalt(III)-phosphine complexes, [Co(dtc)x{(CH3)2P(CH2)nP(CH3)}2}3−x](3−x)+ (x=1, 2; n=1,2,3), [Co(dtc)2{(C6H5)2P(CH2)nP(C6H5)2}]+ (n=1,2,3,4), and trans-[Co(dtc)2(PR3)2]+ (R=C2H5, C6H5) were prepared, where dtc denotes dimethyldithiocarbamate(1–). The molecular structure of [Co(dtc){(CH3)2PCH2P(CH3)2}2](BF4)2 was determined by X-ray ana...

Crystal structures of green (X=NO3−(1), BF4−(2)) and brown (X=BF4−(3) and ClO4−(4)) salts of trans-[CoCl2(N48)]X (N48=1,4,7,10-tetraazacyclopentadecane) were determined by an X-ray diffraction method. The complex cation is a RSSR(SRRS) isomer for the four chiral nitrogen atoms and has approximate C2 symmetry. Green crystals 1 and 2 are monoclinic a...

New cobalt(III)-1,4,7,10-tetraazacyclotetradecane (N47), -pentadecane (N48), and -hexadecane (N49) complexes, trans-[CoCl2(N4x)]+ (x=7 (two isomers), 8 (two isomers), 9 (one isomer)), trans-[Co(NO2)2(N4x)]+ (x=7, 8, 9, one isomer), cis-[Co(NO2)2(N47)]+ (one isomer), and [Co(en)(N4x)]3+ (x=7, 8, one isomer) were synthesized and characterized. For an...

A series of mixed complexes [Co(pyt)3−n (diamine)n]n+ (n=0, 1, and 2; pyt=2-pyridinethiolate(1—) and diamine=ethylenediamine, (R)-propylenediamine, or 2,2′-bipyridine) have been prepared and characterized by means of their visible and ultraviolet absorption, circular dichroism, and magnetic circular dichroism spectra. In the [Co(pyt)3] or [Co(pyt)2...

Reduction(E1/2 (red)) and oxidation(E1/2(ox)) potentials of 32 cobalt(III) mixed-ligand complexes with sulfur, phosphorus, and nitrogen donor atoms were obtained. A good linear relationship was found between the potential difference, ΔE(redox) ≡ e[E1/2(ox) − E1/2(red)], and the first d-d transition energy.

(2-Aminoethyl)dimethylarsine (edma) and its cobalt(III) complexes, trans(X,X),cis(As,As)-[CoX2(edma)2]+ (X=Cl, Br, and I), trans(As,As)- and trans(As,N)-[Co(acac)(edma)2]2+ (acac=acetylacetonate ion), trans(As,N)-[Co(CO3)(edma)2]+, [Co(acac)2(edma)]+, and fac-[Co(edma)3]3+ were prepared and characterized. From a comparison of the first d–d absorpti...

Ligand field irradiation of cis-[CoCl2{(CH3)2PCH2CH2CH2P(CH3)2}2]+ in methanol and cis-[CoCl(H2O){(CH3)2PCH2CH2P(CH3)2}2]2+ in acetonitrile at 5 °C led to isomerization to the trans isomer with quantum yields of 0.010 and 0.070, respectively. The same cis to trans photoisomerization of [CoCl2(R2PCH2CH2PR2)2]+ (R=CH3, C4H9) occurred with much smalle...

Dithiocarbamato complexes, [Co(dtc)3−n(diamine)n]n+ (n=1 and 2 and dtc=dimethyldithiocarbamate) were newly prepared and characterized by means of their absorption, CD, and MCD spectra. (+)500CD-[Co(dtc)(en)2][Sb2(R,R-C4H2O6)2]·5H2O crystallized in the monoclinic space group of P21 with a=14.630(3), b=9.300(1), c=12.023(5) Å, β=110.78(3)°, V=1529.4(...

Molecular structures of cis-[Co(CN)2(acac)(dppe)] (a) and trans(C,N)-[Co(CN)2(acac)(edpp)]·H2O (b) have been determined by X-ray analysis, where acac, dppe, and edpp denote an acetylacetonate ion, 1,2-bis(diphenylphosphino)ethane and (2-aminoethyl)diphenylphosphine, respectively. Crystal data for a: monoclinic, P21⁄a, a=13.975(2), b=19.709(2), c=11...

The H2O2 oxidation of [Co(N,N-dimethyldithiocarbamato-S,S′)(en)2]2+ and [Co(2-pyridinethiolato-S,N(en)2]2+ in acid media gave the novel complexes [Co (N,N-dimethylaminothioxomethanesulfinato-S,O)(en)2]2+ and [Co(2-pyridinesulfenato-S,N)(en)2]2+, respectively. The latter S,N-chelated isomer was photochemically converted into the O,N-chelated linkage...

Rhodium(III) complexes, [Rh(SCH2CH2NH2)3] and [Rh{S(O)CH2CH2NH2}n{S(O)2CH2CH2NH2}3−n](n=3, 2, 1, and 0), were prepared and optically resolved by means of column chromatography or preferential crystallization of diastereomeric molecular compound with (R,R)-tartaric acid, d-C4H6O6·(−)300CD-[Rh{S(O)CH2CH2NH2}3]·H2O or d-C4H6O6·(+)300CD-[Rh{S(O)CH2CH2N...

A series of mixed complexes [Co(pyt)3−n(en)n]n+ (n = 0, 1, and 2) have been newly prepared and characterized by their visible and ultraviolet absorption, circular dichroism, and magnetic circular dichroism spectra (pyt = 2-pyridinethiolato-N,S ligand). In [Co(pyt)3] or [Co(pyt)2(en)]+ complex, only one geometrical isomer, mer(S) or trans(S), has be...

The crystal structure and absolute configuration of diastereomeric molecular compound, d-C4H6O6·(+)500CD[Co{S(O)CH2CH2NH2}3]·H2O, were determined by the X-ray diffraction method. The crystals are orthorhombic with space group P212121, Z=4, and a=13.034(4), b=13.559(6), and c=11.048(8) Å. The rifinement of 1724 reflections (Mo Kα radiation) led to R...

The X-ray photoelectron spectroscopic data of 25 cobalt(III) complexes of CoNxS6−x types are reported(x = 6, 5, 4, 3, and 0). The S2p3⁄2 binding energies can readily be distinguished into eight types of sulfur ligands. The S2p3⁄2, Co2p3⁄2, and Nls binding energies are distributed between two extremes; one represents the case of thiolato and sulfena...

Twelve new mixed sulfenato and sulfinato cobalt(III) complexes were prepared via successive H2O2 oxidation of [Co(SCH2CH2NH2)3], [Co{SCH2CH(COOCH3)NH2}3], and related complexes. These oxidation products, [Co(sulfenato-N,S)n(sulfinato-N,S)3−n] (n=3, 2, 1, and 0), were optically resolved by means of column chromatography or preferential crystallizati...

The Taliban effectively marginalized the school population of Afghanistan, particularly girls, who were legally forbidden to attend school. Since the fall of the Taliban Government, education has become one of the key priorities in the process of reconciliation, reconstruction and development agreed to in Bonn (Government of the Federal Republic of...

Education for Sustainable Development (ESD)-Environmental Education, has been a major concern at most UN summits. The 2002 Johannesburg Summit broadened the vision and re-affirmed the objective of the Millennium evelopment Goals (MDS) and proclaimed the Decade of Education for Sustainable Development for the period 2005 -2014. This emphasized that...