Kristallstrukturen und Normalkoordinatenanalyse der bindungsisomeren Pentachloroselenocyanatorhenate (IV)

Crystal Structure and Normal Coordinate Analysis of Linkage Isomeric Pentachloroselenocyanatorhenates (IV) The X-ray structure determinations on single crystals of (Ph₃PNPPh₃)₂[ReCl₅(NCSe)] ( 1 ) (monoclinic, space group P2₁/n, a = 10.806(2), b = 13.349(2), c = 46.071(4) Å, β = 94.947(9)°, Z = 4) and (Py₂CH₂)[ReCl₅(SeCN)] ( 2 ) (monoclinic, space group P2₁/n, a = 12.044(1), b = 9.838(1), c = 15.686(2) Å, β = 105.913(8)°, Z = 4) reveal, that the nearly linear selenocyanate group (178°) is coordinated via N with the Re–N–C angle of 172.7 ( 1 ) and via Se with the Re–Se–C angle of 107.4° ( 2 ). Based on the molecular parameters of the X-ray determinations the IR and Raman spectra, known from literature for both linkage isomers, have been assigned by normal coordinate analysis. The valence force constants are f_d(ReN) = 1.72 and f_d(ReSe) = 1.20 mdyn/Å.     

Kristallstrukturen,Schwingungsspektren und Normalkoordinatenanalysen von (n-Bu4N)2[ReBr5(NCS)] und (n-Bu4N)2[ReBr5(NCSe)]

Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of ( n -Bu₄N)₂[ReBr₅(NCS)] and ( n -Bu₄N)₂[ReBr₅(NCSe)] The X-ray structure determinations on single crystals of (n-Bu₄N)₂[ReBr₅(NCS)] ( 1 ) (monoclinic, space group P2₁/n, a = 10.9860(9), b = 11.6860(7), c = 35.551(3) Å, β = 91.960(9)°, Z = 4) and (n-Bu₄N)₂[ReBr₅(NCSe)] ( 2 ) (monoclinic, space group P2₁/n, a = 11.0208(15), b = 11.7418(16), c = 35.621(12) Å, β = 92.003(18)°, Z = 4) reveal that the thiocyanate and the selenocyanate group are bonded with the Re–N–C angle of 168.5° ( 1 ) and 169.9° ( 2 ). Based on the molecular parameters of the X-ray determinations the IR and Raman spectra have been assigned by normal coordinate analysis. The valence force constants f_d(ReN) are 1.81 ( 1 ) and 1.75 mdyn/Å ( 2 ).     

Darstellung und Kristallstrukturen von (Ph3PNPPh3)2[Re2Br10] und (Ph4P)[Re2Br9]

Synthesis and Crystal Structures of (Ph₃PNPPh₃)₂[Re₂Br₁₀] and (Ph₄P)[Re₂Br₉] Depending on the molar ratio by reaction of [n-Bu₄N]₂[ReBr₆] with the Lewis acid BBr₃ in dichloromethane the bioctahedral complexes [n-Bu₄N]₂[Re₂Br₁₀] and [n-Bu₄N][Re₂Br₉] are formed. The X-ray structure determination on (Ph₃PNPPh₃)₂[Re₂Br₁₀] (monoclinic, space group C 2/c, a = 20.007(4), b = 15.456(5), c = 24.695(4) Å, β = 107.53(2)°, Z = 4) reveals a centrosymmetric edge-sharing complex anion with approximate D_2h symmetry and mean terminal and bridging Re–Br bond lengths of 2.453 (equatorial), 2.482 (axial) and 2.591 Å, respectively, and a Re–Re distance of 3.880 Å. (Ph₄P)[Re₂Br₉] (triclinic, space group P 1, a = 11.062(2), b = 12.430(3), c = 13.163(5) Å, α = 72.94(2), β = 68.47(2), γ = 82.09(2)°, Z = 2) contains a confacial bioctahedral anion with nearly D_3h symmetry and mean terminal and bridging Re–Br distances of 2.460 and 2.536 Å, respectively, and a Re–Re distance of 2.780 Å.     

Kristallstrukturen,Schwingungsspektren und Normalkoordinatenanalysen der Chloro-Iodo-Rhenate(IV) (CH2Py2)[ReCl5I], cis-(CH2Py2)[ReCl4I2] · 2 DMSO,trans-(CH2Py2)[ReCl4I2] · 2 DMSO und fac-(EtPh3P)2[ReCl3I3]

Crystal Structures, Vibrational Spectra, and Normal Coordinate Analyses of the Chloro-Iodo-Rhenates(IV) (CH₂Py₂)[ReCl₅I], cis -(CH₂Py₂)[ReCl₄I₂] · 2 DMSO, trans -(CH₂Py₂)[ReCl₄I₂] · 2 DMSO, and fac -(EtPh₃P)₂[ReCl₃I₃] [ReCl₅I]^2–, cis-[ReCl₄I₂]^2–, trans-[ReCl₄I₂]^2–, and fac-[ReCl₃I₃]^2– have been synthesized by ligand exchange reactions of [ReI₆]^2– with HCl and are separated by ion exchange chromatography on diethylaminoethyl cellulose. X-ray structure determinations have been performed on single crystals of (CH₂Py₂)[ReCl₅I] ( 1 ) (triclinic, space group P1 with a = 7.685(2), b = 9.253(2), c = 12.090(4) Å, α = 90.06(2), β = 101.11(2), γ = 95.07(2)°, Z = 2), cis-(CH₂Py₂)[ReCl₄I₂] · 2 DMSO ( 2 ) (triclinic, space group P1 with a = 8.662(2), b = 12.109(2), c = 12.9510(12) Å, a = 97.533(11), β = 96.82(2), γ = 89.90(2)°, Z = 2) , trans-(CH₂Py₂)[ReCl₄I₂] · 2 DMSO ( 3 ) (triclinic, space group P1 with a = 9.315(7), b = 9.663(3), c = 15.232(3) Å, α = 80.09(2), β = 81.79(4), γ = 83.99(5)°, Z = 2) and fac-(EtPh₃P)₂[ReCl₃I₃] ( 4 ) (monoclinic, space group P2₁/a with a = 17.453(2), b = 13.366(1), c = 19.420(1) Å, β = 112.132(8)°, Z = 4). The crystal structure of ( 1 ) reveals a positional disorder of the anion sublattice along the asymmetric axis. Due to the stronger trans influence of I compared with Cl on asymmetric axes Cl˙–Re–I′ is caused a mean lenghthening of the Re–Cl˙ distances of 0.020 Å (0.8%) and a shortening of the Re–I′ distances of 0.035 Å (1.3%) with regard to symmetrically coordinated axes Cl–Re–Cl and I–Re–I, respectively. Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu₄N) salts of all four chloro-iodo-rhenates(IV) are assigned by normal coordinate analyses. The weakening of the Re–Cl˙ bonds and the strengthening of the Re–I′ bonds is indicated by a decrease or increase of the valence force constants each by 9%.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von vier bindungsisomeren Tetrachlorodirhodanoosmaten(IV)

Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of Four Linkage Isomeric Tetrachlorodirhodanoosmates(IV) By treatment of cis- or trans-[OsCl₄I₂]^2? with (SCN)₂ in dichloromethane the linkage isomers cis-[OsCl₄(NCS)₂]^2? ( 1 ), trans-[OsCl₄(NCS)(SCN)]^2? ( 2 ), cis-[OsCl₄(NCS)(SCN)]^2? ( 3 ) and trans-[OsCl₄(SCN)₂]^2? ( 4 ) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-Ray structure determinations on single crystals of cis-(Ph₄As)₂[OsCl₄(NCS)₂] (triclinic, space group P1 , a = 10.019(5), b = 11.702(5), c = 21.922(5) Å, α = 83.602(5)°, β = 85.718(5)°, γ = 73.300(5)°, Z = 2), trans-(Ph₄As)₂[OsCl₄ · (NCS)(SCN)] (monoclinic, space group P2₁/c, a = 18.025(5), b = 11.445(5), c = 23.437(5) Å, β = 94.208(5)°, Z = 4), cis-(Ph₄As)₂[OsCl₄(NCS)(SCN)] (triclinic, space group P1 , a = 10.579(5), b = 11.682(5), c = 22.557(5) Å, α = 81.073(5)°, β = 85.807(5)°, γ = 87.677(5)°, Z = 2) and trans-(Ph₄As)₂ · [OsCl₄(SCN)₂] (triclinic, space group P1 , a = 10.615(5), b = 11.691(5), c = 11.907(5) Å, α = 111.314(5)°, β = 96.718(5)°, γ = 91.446(5)°, Z = 1) reveal the complete ordering of the complex anions. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with Os? N? C angles of 171.2° and 174.3° ( 1 ), 162.3° ( 2 ), 172° ( 3 ) and Os? S? C angles of 108.3° ( 2 ), 105.7° ( 3 ) and 105.5° ( 4 ). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu₄N) salts of all four linkage isomers are assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are f_d(OsN) = 1.59 ( 1 ), 1.67 ( 2 ), 1.60 ( 3 ) and f_d(OsS) = 1.27 ( 2 ), 1.31 ( 3 ) and 1.32 mdyn Å^?1 ( 4 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.     

Glycol modified cis -diisopropoxy- bis ( N -phenylsalicylideneiminato)zirconium(IV): syntheses,characterization and low temperature transformation to nanocrystalline zirconia

Zr(OPrⁱ)₄·PrⁱOH reacts with N-phenylsalicylideneimine in anhydrous benzene in 1 : 2 molar ratio to afford [Zr{O(C₆H₄)CH=NPh}₂{OPrⁱ}₂] (1). Further reactions of 1 with various glycols yield heteroleptic complexes of the type [Zr{O(C₆H₄)CH=NPh}₂{O–G–O}] [where–G–= (CH₂)₂ (2), (CH₂CHCH₃) (3), (CH₃CHCHCH₃) (4), (CH₂CHC₂H₅) (5), (CH₂)₃ (6), (CH₂CH₂CHCH₃) (7), and (CH₂)₆ (8)]. All new derivatives have been characterized by elemental analyses, FTIR and NMR (¹H and ¹³C{¹H}) studies. FAB mass spectra of 1 and 7 revealed the monomeric nature of these complexes. Complete hydrolyses and low temperature transformations of 1 and 7 using Sol-Gel technique formed tetragonal phase of ZrO₂ at 700°C, whereas transformation of tetragonal to monoclinic phase occurred at 900°C. SEM observations of these samples indicate formation of agglomerates of nanocrystalline zirconia (Scherer analysis).     

Synthesis and properties of poly[arylene ether (N-arylenebenzimidazole)]s

Poly(arylene ether)s containing N-arylenebenzimidazole groups were prepared by the aromatic nucleophilic displacement reaction of two new bis(hydroxyphenyl-N-arylenebenzimidazole)s with activated aromatic difluorides in sulfolane at 200°C in the presence of anhydrous potassium carbonate. The bis(hydroxyphenyl-N-arylenebenzimidazole)s were prepared from bis(o-aminoanilino) arylenes and phenyl-4-hydroxybenzoate. The polymers were soluble in N-methyl-2-pyrrolidinone and m-cresol and exhibited inherent viscosities from 0.37–0.86 dL/g and glass transition temperatures from 219–289°C. Thermogravimetric analyses showed 5% weight losses from 463–506°C in air and 467–522°C in nitrogen. Unoriented thin films exhibited tensile strengths, moduli, and break elongations at 23°C of 10.2–12.5 ksi, 318–365 ksi, and 4–7%, respectively, and at 177°C of 5.1–6.9 ksi, 256–296 ksi, and 1–5%, respectively. A 50 : 50 random copolymer prepared from 1,3-bis(4-fluorobenzoyl) benzene, 1,1'-(4,4'-biphenylene)-bis[2-(4-hydroxyphenyl)benzimidazole], and 5,5'-bis[2-(4-hydroxyphenyl)benzimidazole] exhibited higher moisture absorption and lower tensile properties than those predicted by a rule of mixtures relationship. The chemical, physical, and mechanical properties of these polymers are discussed. © 1993 John Wiley & Sons, Inc.?     

Synthesis,Spectroscopic, and X‐Ray Diffraction Studies of cis‐Dichlorobis(4‐propanoyl‐2,4‐dihydro‐5‐methyl‐2‐phenyl3 H‐pyrazol‐3‐onato) Tin(IV)

Reaction between an aqueous ethanol solution of tin(II) chloride and that of 4‐propanoyl‐2,4‐dihydro‐5‐methyl‐2‐phenyl‐3 H‐pyrazol‐3‐one in the presence of O₂ gave the compound cis‐dichlorobis(4‐propanoyl‐2,4‐dihydro‐5‐methyl‐2‐phenyl‐3 H‐pyrazol‐3‐onato) tin(IV) [(C₂₆H₂₆N₄O₄)SnCl₂]. The compound has a six‐coordinated Sn^IV centre in a distorted octahedral configuration with two chloro ligands in cis position. The tin atom is also at a pseudo two‐fold axis of inversion for both the ligand anions and the two cis‐chloro ligands. The orange compound crystallizes in the triclinic space group P 1 with unit cell dimensions, a = 8.741(3) Å, b = 12.325(7) Å, c = 13.922(7) Å; α = 71.59(4), β = 79.39(3), γ = 75.18(4); Z = 2 and D_x = 1.575 g cm^–3. The important bond distances in the chelate ring are Sn–O [2.041 to 2.103 Å], Sn–Cl [2.347 to 2.351 Å], C–O [1.261 to 1.289 Å] and C–C [1.401 Å] the bond angles are O–Sn–O 82.6 to 87.7° and Cl–Sn–Cl 97.59°. The UV, IR, ¹H NMR and ¹¹⁹Sn Mössbauer spectral data of the compound are reported and discussed.     

Destruktive Komplexierung des dimeren Diorganylzinn(IV)‐hydroxids [Me2Sn(A)(μ‐OH)]2 (HA = Benzol‐1,2‐disulfonsäureimid): Bildung und Strukturen der Einkernkomplexe [Me2Sn(A)2(OPPh3)2] und [Me2Sn(phen)2]2⊕ · 2 A⊖ · MeCN

Polysulfonylamines. CXVI. Destructive Complexation of the Dimeric Diorganyltin(IV) Hydroxide [Me₂Sn(A)(μ‐OH)]₂ (HA = Benzene‐1,2‐disulfonimide): Formation and Structures of the Mononuclear Complexes [Me₂Sn(A)₂(OPPh₃)₂] and [Me₂Sn(phen)₂]^2⊕ · 2 A^⊖ · MeCN Destructive complexation of the dimeric hydroxide [Me₂Sn(A)(μ‐OH)]₂, where A^⊖ is deprotonated benzene‐1,2‐disulfonimide, with two equivalents of triphenylphosphine oxide or 1,10‐phenanthroline in hot MeCN produced, along with Me₂SnO and water, the novel coordination compounds [Me₂Sn(A)₂(OPPh₃)₂] ( 3 , triclinic, space group P 1) and [Me₂Sn(phen)₂]^2⊕ · 2 A^⊖ · MeCN ( 4 , monoclinic, P2₁/c). In the uncharged all‐trans octahedral complex 3 , the heteroligands are unidentally O‐bonded to the tin atom, which resides on a crystallographic centre of inversion [Sn–O(S) 227.4(2), Sn–O(P) 219.6(2) pm, cis‐angles in the range 87–93°; anionic ligand partially disordered over two equally populated sites for N, two S and non‐coordinating O atoms]. The cation occurring in the crystal of 4 has a severely distorted cis‐octahedral C₂N₄ coordination geometry around tin and represents the first authenticated example of a dicationic tin(IV) dichelate [R₂Sn(L–L′)₂]^2⊕ to adopt a cis‐structure [C–Sn–C 108.44(11)°]. The five‐membered chelate rings are nearly planar, with similar bite angles of the bidentate ligands, but unsymmetric Sn–N bond lengths, each of the longer bonds being trans to a methyl group [ring 1: N–Sn–N 71.24(7)°, Sn–N 226.81(19) and 237.5(2) pm; ring 2: 71.63(7)°, 228.0(2) and 232.20(19) pm]. In both structures, the bicyclic and effectively C_S symmetric A^⊖ ions have their five‐membered rings distorted into an envelope conformation, with N atoms displaced by 28–43 pm from the corresponding C₆S₂ mean plane.     

Darstellung,Kristallstruktur und Normalkoordinatenanalyse der bindungsisomeren Pentachlororhodanoosmate(IV)

Preparation, Crystal Structure and Normal Coordinate Analysis of Linkage Isomeric Pentachlororhodanoosmates(IV) By treatment of [OsCl₅I]^2? with (SCN)₂ in dichloromethane the linkage isomers [OsCl₅(NCS)]^2? and [OsCl₅(SCN)]^2? are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-ray structure determination on single crystals of (Ph₄As)₂[OsCl₅(NCS)] (monoclinic, space group P2₁/a, a = 18.872(2), b = 11.6024(2), c = 22.786(1), β = 109.057(1)°, Z = 4) and (Ph₄As)₂[OsCl₅(SCN)] (monoclinic, space group P2₁/a, a = 19.057(2), b = 11.306(2), c = 22.612(1), β = 106.64(2)°, Z = 4) reveals the complete ordering of the complex anions. The thiocyanate group is located above one of the Cl ligands of the equatorial plane with the Os? N? C angle of 166.1° for N bonding and the Os? S? C angle of 109.9° for S bonding. The IR and Raman spectra of both linkage isomers known from literature are assigned by normal coordinate analysis based on the general valence force field using the molecular parameters of the X-ray determination. The valence force constants are f_d(OsN) = 1,81 and f_d(OsS) = 1,32 mdyn/Å. Taking into account increments of the trans influence a good adjustment between observed and calculated frequencies is achieved.     

Darstellung,spektroskopische Charakterisierung und Kristallstrukturen von [(C5H5N)2CH2][PtCl5(SCN)] und cis-[(C5H5N)2CH2][PtCl4(SCN)2]

Preparation, Spectroscopic Characterization, and Crystal Structures of [(C₅H₅N)₂CH₂][PtCl₅(SCN)] and cis -[(C₅H₅N)₂CH₂][PtCl₄(SCN)₂] By treatment of [PtCl₆]^2– with SCN^– in aqueous solution a mixture of chlorothiocyanatoplatinates(IV) is formed, from which [PtCl₅(SCN)]^2– and cis-[PtCl₄(SCN)₂]^2– have been separated by ion exchange chromatography on diethylaminoethyl cellulose. X-Ray structure determinations on single crystals of [(C₅H₅N)₂CH₂][PtCl₅(SCN)] ( 1 ) (tetragonal, space group P 4₃, a = 7.687(1), c = 29.698(4), Z = 4) and cis-[(C₅H₅N)₂CH₂][PtCl₄(SCN)₂] ( 2 ) (monoclinic, space group P 2₁/n, a = 11.2467(9), b = 15.0445(10), c = 11.3179(13), β = 92.840(9)°, Z = 4) show, that the thiocyanate groups are coordinated via S atoms with average Pt–S distances of 2.339 Å and Pt–S–C angles of 104.7° up to 107.1°. Using the molecular parameters of the X-ray determinations the low temperature (10 K) IR and Raman spectra have been assigned by normal coordinate analyses. The valence force constants of the S–Pt–Cl˙ axes are f_d(PtS) = 1.81 ( 1 ) and 1.87 ( 2 ), f_d(PtCl ^× ) = 1.77 ( 1 ) and 1.81 ( 2 ), of the Cl–Pt–Cl axes are f_d(PtCl) = 1.93 ( 1 ) and 1.90 mdyn/Å ( 2 ). The ¹⁹⁵Pt NMR spectra from dichlormethane solutions exhibit each one sharp signal at 3975.6 ( 1 ) and 3231.6 ppm ( 2 ), respectively.     

Synthesis and crystal structure of Fe[(Te1.5Se0.5)O5]Cl,the first iron compound with selenate(IV) and tellurate(IV) groups

During the search for selenium analogues of FeTe₂O₅Cl, the new iron (III) tellurate(IV) selenate(IV) chloride with the composition Fe[(Te_1.5Se_0.5)O₅]Cl was synthesized by chemical vapor transport (CVT) reaction and characterized by TGA-, EDX-,SCXRD-analysis, as well as IR and Raman spectroscopy. It was found that Fe[(Te_1.5Se_0.5)O₅]Cl crystallizes in the monoclinic space group P2₁/c with unitcell parameters a = 5.183(3) Å, b = 15.521(9) Å, c = 7.128(5) Å and β = 107.16(1)°. The crystal structure of Fe[(Te_1.5Se_0.5)O₅]Cl represents a new structure type and contains electroneutral heteropolyhedral layers formed by dimers of the [FeO₅Cl]^8– octahedra, linked via common O-O edges, and mixed [Te₃SeO₁₀]^4- tetramers. Adjacent layers are stacked along the b axis and linked by weak residual bonds. The new compound is stable up to 420 °C. DFT calculations predict Fe[(Te_1.5Se_0.5)O₅]Cl to be a wide-gap semiconductor with the band gap of ca. 2.7 eV.     

Neue Halogenochalkogen(IV)‐Säuren: [H3O(Benzo‐18‐Krone‐6)]2[Te2Br10] und [H5O2(Dibenzo‐24‐Krone‐8)]2[Te2Br10]

Novel Halogenochalcogeno(IV) Acids: [H₃O(Benzo‐18‐Crown‐6)]₂[Te₂Br₁₀] and [H₅O₂(Dibenzo‐24‐Crown‐8)]₂[Te₂Br₁₀] Systematic studies on halogenochalcogeno(IV) acids containing tellurium and bromine led to the new crystalline phases [H₃O(Benzo‐18‐Crown‐6)]₂[Te₂Br₁₀] ( 1 ) and [H₅O₂(Dibenzo‐24‐Crown‐8)]₂[Te₂Br₁₀] ( 2 ). The [Te₂Br₁₀]^2‐ anions consists of two edge‐sharing distorted TeBr₆ octahedra, the oxonium cations are stabilized by crownether. ( 1 ) crystallizes in the monoclinic space group P2₁/n with a = 14.520(5) Å, b = 22.259(6) Å, c = 16.053(5) Å, β = 97.76(3)° and Z = 4, whereas ( 2 ) crystallizes in the triclinic space group with a = 11.005(4) Å, b = 12.103(5) Å, c = 14.951(6) Å, α = 71.61(3)°, β = 69.17(3)°, γ = 68.40(3)° and Z = 1.     

Synthese und spektroskopische Charakterisierung von Fluorocarbonylosmaten sowie Normalkoordinatenanalyse und Kristallstruktur von fac-[OsF3Br2(CO)]2–

Synthesis and Spectroscopic Characterization of Fluorocarbonylosmates, Normal Coordinate Analysis and Crystal Structure of fac -[OsF₃Br₂(CO)]^2– By treatment of (n-Bu₄N)₂[OsBr₅(CO)] with TlF in C₆H₅CF₃ fac-(n-Bu₄N)₂[OsF₃Br₂(CO)] is formed, from which salts with the cations (Et₄N)⁺, (py₂CH₂)²⁺, Tl⁺ and Cs⁺ are obtainable. Oxidation of the by-product [OsF₅(CO)]^2– with Cl₂ yields [OsF₅(CO)]^– which ¹⁹F NMR spectrum reveals a quintet (δ_F = 89.9) and a dublet (43.5 ppm) in the ratio 1 : 4 with coupling constants ²J_FF = 94.9 Hz. Simultaneously produced mer-[OsF₃Cl₂(CO)]^– exhibits in the high field region a triplet (δ_F = –70.4) and a dublet (–66.2 ppm) in the ratio 1 : 2 and ²J_FF = 9.5 Hz. The X-ray structure determinations of fac-Tl₂[OsF₃Br₂(CO)] ( 1 ) (monoclinic P2₁/n, a = 11.143(12), b = 11.654(4), c = 13.751(10) Å, β = 91.50(6)°, Z = 8) and fac-(py₂CH₂)[OsF₃Br₂(CO)] · 1/2(CH₃)₂CO ( 2 ) (triclinic, P 1, a = 8.432(1), b = 9.009(1), c = 12.402(2) Å, α = 80.30(1), β = 79.68(2), γ = 68.14(1)°, Z = 2) result in nearly C_s symmetry of the complex anion with bond lengths in the ranges Os–F = 1.98–2.08, Os–Br = 2.45–2.46, Os–C = 1.83–1.84, C–O = 1.10 – 1.17 Å. Using the molecular parameters of the X-ray determinations the IR spectra have been assigned by normal coordinate analysis. The valence force constants are f_d(CO) = 15.4–15.7, f_d(OsC) = 4.4–4.7, f_d(OsF) = 2.4–2.7, f_d(OsF˙) = 1.6–2.0, f_d(OsBr) = 1.7–2.1 mdyn/Å.     

[H3O · (Dibenzo-18-crown-6)][Te2Br9] and [H5O2][Te2Cl9] · 2 C4H8O2: Two New Oxonium Halotellurates(IV) Containing a Novel Type of [Te2X9]– Anions

Red crystals of [H₃O · (dibenzo-18-crown-6)][Te₂Br₉] ( 1 ) were isolated from a solution of TeBr₄ and dibenzo-18-crown-6 in CH₃CN containing a small amount of hydrobromic acid. The compound crystallizes in the triclinic space group P 1 with the cell dimensions a = 9.010(2), b = 13.403(3), c = 14.606(4) Å, α = 98.94(2)°, β = 100.40(2)°, and γ = 91.40(2)° (150 K). From a solution of TeCl₄ in 1,4-dioxane containing hydrochloric acid [H₅O₂][Te₂Cl₉] · 2 C₄H₈O₂ ( 2 ) precipitates as colorless crystals in the orthorhombic space group Pnma with the cell dimensions a = 17.023(4), b = 13.389(4), and c = 10.900(3) Å (150 K). In both structures the [Te₂X₉]^– anion (X = Cl, Br) consists of one TeX₆ octahedron and one TeX₅ square pyramidal unit connected by a common edge. In compound 1 the coordination sphere of the square pyramidal fragment is completed by a very weakly η⁶ bound benzo group of the cationic unit. In compound 2 an oxygen atom of the oxonium ion weakly interacts with the fivefold coordinated tellurium atom. The cationic units are a crown ether oxonium complex in 1 and a supramolecular 1,4-dioxane-oxonium network in 2 .     

New poly(amide-imide)s syntheses. VII. Preparation and properties of poly(amide-imide)s derived from 1,5-bis(4-aminophenoxy) naphthalene,trimellitic anhydride,and various aromatic diamines

New bis(phenoxy)naphthalene-containing poly(amide-imide)s having an inherent viscosity in the range of 0.62–1.09 dL/g were prepared by the direct polycondensation of 1,5-bis(4-trimellitimidophenoxy) naphthalene ( I ) and various aromatic diamines using triphenyl phosphite and pyridine as condensing agents in N-methyl-2-pyrrolidone (NMP) in the presence of calcium chloride. The diimide-diacid (I) was prepared by the condensation of 1,5-bis(4-aminophenoxy) naphthalene and trimellitic anhydride. Most of the polymers were soluble in aprotic solvents such as NMP and N,N-dimethylacetamide (DMAc), and afforded transparent, flexible and tough films upon casting from DMAc solutions. Measurements of wide-angle X-ray diffraction revealed that those polymers containing p-phenylene or oxyphenylene groups were characterized as crystalline polymers. Tensile strength and initial moduli of the polymer films ranged from 61–86 MPa and 1.83–2.21 GPa, respectively. Glass transition temperatures of the polymers were in the range of 231–340°C. The melting points of the crystalline polymers ranged from 375–430°C. The 10% weight loss temperatures were above 512°C in nitrogen and 481°C in air. © 1993 John Wiley & Sons, Inc.     

Einkristalle des Cer(IV)–Oxotellurats(IV) CeTe2O6

Single Crystals of the Cerium(IV) Oxotellurate(IV) CeTe₂O₆ Orange‐red, coffin‐shaped single crystals of CeTe₂O₆ (monoclinic, P2₁/n; a = 703.71(5), b = 1106.32(8), c = 735.24(5) pm, β = 108.066(6)°; Z = 4) were obtained by the reaction of admixtures of cerium dioxide and tellurium dioxide (CeO₂, TeO₂; molar ratio 1 : 2) in the presence of fluxing CsCl (750 °C, 4 d) in evacuated silica tubes. The crystal structure contains eightfold coordinated Ce⁴⁺ cations, which are surrounded by irregular trigonal dodecahedra of oxygen atoms. The interconnection of these [CeO₈] polyhedra occurs via two edges (O2–O2′ and O3–O3′) with equatorial orientation relative to each other forming zigzag chains {[CeO_4/1O_4/2]^8–} which run parallel to [100] and arrange as a hexagonal packing of rods. Both crystallographically different Te⁴⁺ cations exhibit trigonal non‐planar coordination figures (ψ¹ tetrahedra) with three oxygen atoms each as a result of the stereochemical activity of the non‐binding electron pairs (“lone pairs”). They also are responsible for the necessary cross‐linkage of the anionic {[CeO₆]^8–} chains. The isotypical relationship with Ce(SeO₃)₂ therefore justifies the formulation Ce(TeO₃)₂ for CeTe₂O₆.     

Temperature‐modulated differential scanning calorimetry studies on the origin of double melting peaks in isothermally melt‐crystallized poly(L‐lactic acid)

In this work, the melting behaviors of nonisothermally and isothermally melt‐crystallized poly(L ‐lactic acid) (PLLA) from the melt were investigated with differential scanning calorimetry (DSC) and temperature‐modulated differential scanning calorimetry (TMDSC). The isothermal melt crystallizations of PLLA at a temperature in the range of 100–110 °C for 120 min or at 110 °C for a time in the range of 10–180 min appeared to exhibit double melting peaks in the DSC heating curves of 10 °C/min. TMDSC analysis revealed that the melting–recrystallization mechanism dominated the formation of the double melting peaks in PLLA samples following melt crystallizations at 110 °C for a shorter time (≤30 min) or at a lower temperature (100, 103, or 105 °C) for 120 min, whereas the double lamellar thickness model dominated the formation of the double melting peaks in those PLLA samples crystallized at a higher temperature (108 or 110 °C) for 120 min or at 110 °C for a longer time (≥45 min). © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 466–474, 2007     

New poly(amide–imide) syntheses. XXI. Synthesis and properties of aromatic poly(amide–imide)s based on 2,6-bis(4-trimellitimidophenoxy)naphthalene and aromatic diamines

A novel polymer-forming diimide–diacid, 2,6-bis(4-trimellitimidophenoxy)naphthalene, was prepared by the condensation reaction of 2,6-bis(4-aminophenoxy)naphthalene with trimellitic anhydride (TMA). A series of novel aromatic poly(amide–imide)s containing 2,6-bis(phenoxy)naphthalene units were prepared by the direct polycondensation of the diimide–diacid with various aromatic diamines using triphenyl phosphite (TPP) in N-methyl-2-pyrrolidone (NMP)/pyridine solution containing dissolved calcium chloride. Thirteen of the obtained polymers had inherent viscosities above 1.01 dL/g and up to 2.30 dL/g. Most of polymers were soluble in polar solvents such as DMAc and could be cast from their DMAc solutions into transparent, flexible, and tough films. These films had tensile strengths of 79–117 MPa, elongation-at-break of 7–61%, and initial moduli of 2.2–3.0 GPa. The wide-angle X-ray diffraction revealed that some polymers are partially crystalline. The glass transition temperatures of some polymers could be determined with the help of differential scanning calorimetry (DSC) traces, which were recorded in the range 232–300°C. All the poly(amide–imide)s exhibited no appreciable decomposition below 450°C, and their 10% weight loss temperatures were recorded in the range 511–577°C in nitrogen and 497–601°C in air. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 919–927, 1998     

Synthesis and characterization of a new tin(IV) complex for fabrication of an organic light-emitting diode (OLED) and photoluminescence properties of the tin oxide core

A new tin(IV) complex, (C₁₃H₁₀NO)[SnCl₄(C₉H₆NO)]·2CH₃OH, was prepared in a facile process and characterized by ¹H, ¹³C, and ¹¹⁹Sn NMR, IR, and UV spectroscopy in addition to single-crystal X-ray diffraction analysis. Current–voltage (I–V) characteristics, photoluminescence (PL), and electroluminescence (EL) properties of the complex have been investigated and an application of the prepared complex in fabrication of an organic light-emitting diode has been demonstrated. The EL of the compound exhibits blue–green emission at 494?nm. Tin(IV) oxide core that resulted from direct thermal decomposition of the complex at 450?°C in air was characterized by X-ray powder diffraction and scanning electron microscopy; then, the PL property was investigated and compared with the PL of the complex. The tin(IV) oxide core showed a band gap of ～3.81?eV determined from the UV/visible absorption spectrum. The tin oxide core showed stable PL with one emission peak centered at 581?nm.