Die Kristallstruktur der 2,4, 6-Trimethylpimelinsäuren 1. Mitteilung

The crystal structure of the stereoisomer m.p. 130° of 2,4,6-trimethylpimelic acid has been determined by three-dimensional X-ray analysis. The cristals are monoclinic, a = 10.35, b = 10.70, c = 11.61 Å, β = 110°12′, Z = 4, space group P_{2 1/c}, the structure has been solved by direct methods and refined by least-squares methods. The configuration of the acid is given by formula I; the chirality of the asymmetric centres is (2-R, 4-r, 6-S).     

Absolute Konfiguration von Antheraxanthin, «cis-Antheraxantliirt» und der diastereomeren Mutatoxanthine

Absolute Configuration of Antheraxanthin, ‘cis-Aritheraxanthin’ and of the Stereoisomeric Mutatdxanthins The assignement of structure 2 to antheraxanthin (all-E)-(3 S, 5 R, 6 S, 3′ R)-5,6-epoxy-5,6-dihydro-β,β-carotene-3,3′-diol and of 1 to ‘cis-antheraxanthin’ (9Z)-(3 S, 5 R, 6 S, 3′ R)-5,6-epoxy-5,6-dihydro-β,β-carotene-3,3′-diol is based on chemical correlation with (3 R, 3′ R)-zeaxanthin and extensive ¹H-NMR. measurements at 400 MHz. ‘Semisynthetic antheraxanthin’ ( = ‘antheraxanthin B’) has structure 6 . For the first time the so-called ‘mutatoxanthin’, a known rearrangement product of either 1 or 2 , has been separated into pure and crystalline C(8)-epimers (epimer A of m.p. 213° and epimer B of m.p. 159°). Their structures were assigned by spectroscopical and chiroptical correlations with flavoxanthin and chrysanthemaxanthin. Epimer A is (3 S, 5 R, 8 S, 3′ R)-5,8-epoxy-5,8-dihydro-β,β-carotene-3,3′-diol ( 4 ; = (8 S)mutatoxanthin) and epimer B is (3 S, 5 R, 8 R, 3′ R)-5,8-epoxy-5,8-dihydro-β,β-carotene-3,3′-diol ( 3 ; = (8 R)-mutatoxanthin). The carotenoids 1 – 4 have a widespread occurrence in plants. We also describe their separation by HPLC. techniques. CD. spectra measured at room temperature and at ? 180° are presented for 1 – 4 and 6 . Antheraxanthin ( 2 ) and (9Z)-antheraxanthin ( 1 ) exhibit a typical conservative CD. The CD. Spectra also allow an easy differentiation of 6 from its epimer 2 . The isomeric (9Z)-antheraxanthin ( 1 ) shows the expected inversion of the CD. curve in the UV. range. The CD. spectra of the epimeric mutatoxanthins 3 and 4 (β end group) are dissimilar to those of flavoxanthin/chrysanthemaxanthin (ε end group). They allow an easy differentiation of the C (8)-epimers.     

Konkurrenz von Endoperoxid- und Hydroperoxid-Bildung bei der Umsetzung von Singulett-Sauerstoff mit cyclischen,konjugierten Dienen. Teil I

Competition of Endoperoxide and Hydroperoxide Formation in the Reaction of Singlet Oxygen with Cyclic, Conjugated Dienes Rose-bengal-sensitized photooxygenation of (?)-(R)-α-phellandrene ( 1 ) in MeOH at room temperature yielded a complex mixture of products, contrary to previous reports describing cis-(3S, 6R)-epidioxy-p-menthene ( 2 ) and trans-(3R, 6S)-epidioxy-p-menthene ( 3 ) as the only products. The mixture was separated by prep. HPLC (silica gel, pentane/Et₂O 9:1). Besides the known endoperoxides 2 (yield 39%) and 3 (26%), all those hydroper-oxides, which can be deduced from an ene reaction of ¹O₂ with 1 , were isolated, i.e. 4β-p-mentha-2,5-dien-1β-yl hydroperoxide ( 4 ) (14%), 4β-p-mentha-2,5-dien-1α-yl hydroperoxide ( 5 ) (9%), (2R, 4R)-p-mentha-1(7), 5-dien-2-yl hydroperoxide ( 6 ) (2,1%), (2S, 4R)-p-mentha-1(7),5-dien-2-yl hydroperoxide ( 7 ) (1,5%) and (1R)-p-mentha-3,6-dien-yl hydroperoxide ( 8 ; 1,5%; Scheme 1). Furthermore, the constant cis/trans ratio for all diastereoisomeric pairs ( 2 / 2 , 4 / 2 , 6 / 2 ) was striking. With the help of the two possible conformers 1a and 1b of the starting material a model of a common first step for endoperoxide as well as for hydroperoxide formation is developed. A photooxygenation at ?50° supports this model. The absolute value of the cis/trans ratio changes in the same way for the endoperoxides and the hydroperoxides.     

Trennung und absolute Konfiguration der C(8)-epimeren (all-E)-Neochrome (Trollichrome) und -Dinochrome

Separation and Absolute Configuration of the C(8)-Epimeric (app-E)-Neochromes (Trollichromes) and -Dinochromes The C(8′)-epimers of (all-E)-neochrome were separated by HPLC and carefully characterized. The faster eluted isomer, m.p. 197.8–198.3°, is shown to have structure 3 ((3S,5R,6R,3′S,5′R,8′R)-5′,8′-epoxy-6,7-dodehydro-5,6,5′,8′-tetrahydro-β,β-carotene-3,5,3′-triol). To the other isomer, m.p. 195-195.5°, we assign structure 6 , ((3S,5R,6R,3′S,5′R,8′R)-5′,8′-epoxy-6,7-didehydro-5,6,5′,8′-tetrahydro-β,β-carotene-3,5,3′-triol). The already known epimeric dinochromes (= 3-O-acetylneochromes) can now be formulated as 4 and 5 , (‘epimer 1’ and its trimethylsilyl ether) and 7 and 8 , (‘epimer 2’ and its trimethylsilyl ether), respectively.     

Synthese und Kristallstruktur von Vanadium(III)‐borophosphat,V2[B(PO4)3]

Synthesis and Crystal Structure of Vanadium(III) Borophosphate, V₂[B(PO₄)₃] By reaction of boron phosphate, BPO₄, and vanadium(IV)‐oxide, VO₂, at 1050 °C a hitherto unknown vanadium(III)‐borophosphate is formed. Its composition was found to be V₂BP₃O₁₂, its structure was elucidated by single crystal X‐ray diffraction, the cell parameters are: a = b = 13.9882Å; c = 7.4515Å; α = β = 90°, γ = 120°; Z = 6; space group: P6 3/m. Noteworthy features of the structure are V₂O₉ units (two V^IIIO₆ octahedra connected via their faces) and isolated trisphosphatoborate groups, B(PO₄)₃. By shared oxide ions, the aforementioned groups are interconnected, thus forming a three dimensional network. The structural relation between the title compound and an analogous chromium compound is discussed.     

Studies on chiral thiophosphoric acids and their derivatives: 4. The stereospecific synthesis of optically active O-ethyl O-phenyl O-(1-methyl-2-ethoxycarbonyl) vinyl phosphorothionate

The stereoisomers (3 and 4) of O-ethyl O-phenyl O-(1-methyl-2-ethoxycarbonyl) vinyl phosphorothionate have been synthesized by the reaction of optically active O-ethyl O-phenyl phosphorothiochloride 2 with ethyl acetoacetate under different conditions. 3 (100% Z-isomer, determined by ¹H NMR) was synthesized by the reaction of 2 with ethyl sodio-acetoacetate in the mixed solvent of 1:3 toluene-dioxane at 50°C. 4 (>95% E-isomer) was obtained by the reaction of 2 with ethyl acetoacetate in presence of t-BuOK in DMSO at 15°C. 100% E-isomer 4 was separated from crude 4(>95% E-isomer) by column chromatography on silica gel (petroleum ether-ether 6:1). By this reaction either Z- or E-isomers were formed with inversion of the configuration at phosphorus atom. Thus, six stereoisomers of 3 and 4 which were prepared from 2 (RS, S, R) by the above method namely (RS)-Z, (R)-Z, (S)-Z and (RS)-E, (R)-E, (S)-E.     

Über Pterinchemie. 85. Mitteilung. Polyacetylierte 5,6,7,8-Tetrahydro-D- und -L-neopterine. Ein besonderer Fall von N(5)-Alkylierung des 5,6,7,8-Tetrahydroneopterin-Gerüstes

Polyacetylated 5,6,7,8-Tetrahydro-D - and L -neopterins. A Special Case of N(5)-Alkylation of 5,6,7,8-Tetrahydroneopterins Improved conditions are reported for the preparation of the earlier described (6R)- and (6S)-1′-O,2′-O,3′-O,2-N,5-pentaacetyl-5,6,7,8-tetrahydro-L -neopterins, one of which could be obtained as pure crystals. Its structure, determined by X-ray-diffraction analysis, corresponds to the (6R)-enantiomer. The method has also been used to make the corresponding D -diastereoisomers. Further acetylation of (6RS)-1′-O,2′-O,3′-O,2-N-tetraacetyl-5,6,7,8-tetrahydro-D -neopterin under drastic conditions yields a mixture of several polyacetylated D -neopterin derivatives and a polyacetylated ethyl-tetrahydro-D -neopterin which was isolated in crystalline form and established by X-ray-diffraction analysis to be (6R)-1′-O,2′-O,3′-O,4-O,2-N,2-N,8-heptaacetyl-5-ethyl-5,6,7,8-tetrahydro-D -neopterin.     

Beiträge zum thermischen Verhalten von Sulfaten. II. Zur thermischen Dehydratisierung des ZnSO4 · 7 H2O und zum Hochtemperaturverhalten von wasserfreiem ZnSO4

Contributions to the Thermal Behaviour of Sulfates. II. On the Thermal Dehydration of ZnSO₄ · 7 H₂O and the Effect of High Temperature upon Anhydrous ZnSO₄ The dehydration of ZnSO₄ · 7 H₂O and effect of high temperature upon unhydrous ZnSO₄ was examined by means of continous high temperature Guinier photographs. On heating in air ZnSO₄ · 7 H₂O decomposes stepwise to ZnSO₄ · 6 H₂O, to an unknown hydrate, to the monohydrate and finally to N? ZnSO₄, which is the thermodynamically stable modification at S.T.P. At about 700°C a reversible transformation to H-ZnSO₄ can be observed which can start from N? ZnSO₄ or H-ZnSO₄, proceeds to the oxide sulfate Zn₃O(SO₄)₂ and finally to ZnO. ZnSO₄ · 6 H₂O crystallizes monoclinically in the hexahydrite structure with a_25°C = 9.981 Å, b_25°C = 7.250 Å, c_25°C = 24.280 Å, β_25°C = 98.45°, Z = 8, space group: C 2/c. Cubic H-ZnSO₄ is the first A²⁺B⁶⁺O₄ compound of H-Cristobalit structure; probable space group F 4 3 m with a_700°C = 7.18 Å, Z =4, N-Zn₃O(SO₄)₂ is monoclinic probable space group B 2 with a_25°c=13.987 Å, b_25°c=6.706 Å, c_25°c =7.379 Å β_25°c=90.69°, Z=4, Above 420°C N-Zn₃(SO₄)₂ becomes orthorhombic where at first of all H′-Zn₃O(SO₄)₂ which has a reversible transformation point to H-Zn₃O(SO₄)₂ at 655°C is formed. The probable space group of H-Zn₂O(SO₄)₂ is C 222₁ with a _850°C = 7.36 Å, b_350°C = 13.96 Å, c_850°C = 6.79 Å Z = 4, The solid solution N? Cu_1,5Zn_1,5O(SO₄)₂ is isotypic with N? Zn₃O(SO₄)₂ and has the lattice constants a_25°C = 14.03 Å, b_25°C = 6.62 Å, c_25°C = 7.33 Å, β_25°C = 90.58°, Transoformations into the non quenchable high temperature modifications H-ZnSO₄, H′-Zn₃O(SO₄)₂ and H-Zn₃O(SO₄)₂ are displacive. The thermal expansion of N-ZnSO₄ and H-ZnSO₄ and H-ZnSO₄ has been exa-mined.     

Die Kristallstruktur von 1,4-trans-Cyclohexan-dicarbonsäure

Crystals of 1,4-trans-cyclohexane-dicarboxylic acid are monoclinic, a = 5.60 Å, b = 9.63 Å, c = 8.05 Å, γ = 107°14′, space group P2₁/b (first setting), with 2 centrosymmetric molecules in the unit cell. The structure has been solved by direct methods and refined by full-matrix least-squares analysis of three-dimensional intensity data. The mean CCC-angle in the cyclohexane ring is found 112.0°. The conformation of the carboxylic group in various acids is discussed.     

Organische Phosphorverbindungen XXXVII. Darstellung und Eigenschaften von Bis-(dialkoxyphosphonyl-methyl)-, Bis-(alkoxyphosphinyl-methyl)-und Bis-(oxophosphoranyl-methyl)-phosphinsäureestern sowie der entsprechenden Säuren [1]

Bis-chloromethyl-alkyl-and - aryl-phosphine oxides, (CICH₂₎₂P(O)R, which are obtained by reaction of (CICH₂₎₂P(O)Cl with GRIGNARD reagents, undergo a MICHAELIS -ARBUSOV reaction when heated for several hours with trivalent phosphorus esters (phosphites, phosphonites, or phosphinites) at 170–180°C. The reaction affords bis-(dialkyloxyphosphonyl-methyl)-, bis (alkyloxyphosphinyl-methyl)-, and bis-(oxophosphoranyl-methyl)-, -alkyl- or -aryl-phosphine oxides, R(O)P[CH₂P(O)R′R″]₂ R = CH₃, C₂H₅, n-C₈H₁₇, n-C₁₂H₂₅, C₆H₅; R′ and R″ = C₂H₅O, C₄H₉O, C₆H₅, CH₃ in good yields. Conversion of the compounds containing alkyloxy groups to the free acids is achieved by refluxing with conc. HCl. Bis-(dihydroxyphosphonyl-methyl)-dodecylphosphine oxide, n-C₁₂H₂₅(O)P[CH₂P(O) (OH)_2]2, obtained by hydrolysis of the all-ethyl ester, titrates in aqueous solution as a tetrabasic acid with breaks at pH = 4 (two equivalents), pH = 6,9 (one equivalent) and pH = 9,6 (one equivalent). This acid, its disodium salt (m. p. 405–410°) and its tetrasodium salt (m.p. > 460°) are surface active and are excellent chelating agents. The ¹H- and ³¹P-NMR. spectra of all the compounds prepared are discussed.     

Beiträge zur Kristallchemie und zum thermischen Verhalten von wasserfreien Phosphaten. XXXXII Die ersten Iridiumphosphate

The First Iridiumphosphates Two polymorphs of iridium(III)‐metaphosphate Ir(PO₃)₃ and an iridium(IV)‐silicophosphate (Ir_1?xSi_x)₃[Si₂O(PO₄)₆] (x ～ 0.5) were synthesized and their crystal structures determined from single‐crystal x‐ray data. Pale pink needles of triclinic Ir(PO₃)₃ (Ru(PO₃)₃ structure type, (No. 2), Z = 2, a = 6.9574(6) Å, b = 10.3628(9) Å, c = 5.0288(4) Å, α = 92.28(1)°, β = 92.80(1)°, γ = 98.60(1)°, 1574 independent reflections, 122 parameters, R₁ = 0.028, wR₂ = 0.061) were grown from a metaphosphoric acid melt. Pale pink prisms of C‐type Ir(PO₃)₃ (C‐Al(PO₃)₃ structure type, Cc (No. 14), Z = 12, a = 13.103(2) Å, b = 19.183(1) Å, c = 9.354(1) Å, β = 127.19(1)°, 4254 independent reflections, 354 parameter, R₁ = 0.024, wR₂ = 0.062) were obtained by chemical vapour transport (900 °C → 800 °C, addition of IrCl₃·xH₂O). Both metaphosphates are built of [Ir^IIIO₆] octahedra and infinite chains. The latter have a translation period of three phosphate tetrahedra in the triclinic modification and six in the monoclinic. 1D and double‐quantum filtered 2D ³¹P‐MAS‐NMR spectra of C‐type Ir(PO₃)₃ confirm the chain structure and reveal a chemical shift range between ?4,8 and ?30,9 ppm for the 9 crystallographically independent, however chemically similar phosphate groups. Pale orange crystals of (Ir_1?xSi_x)₃[Si₂O(PO₄)₆] (Si₃[Si₂O(PO₄)₆] structure type, (No. 148), Z = 3, a = 7.8819(8) Å, c = 24.476(4) Å, 1086 independent reflections, 56 parameters, R₁ = 0.061, wR₂ = 0.190) occurred in chemical vapour transport experiments aiming at the crystallization of C‐Ir(PO₃)₃. The crystal structure of the silicophosphate consists of isolated [Ir^IVO₆] octahedra and [Si₂O(PO₄)₆]^12? heteropolyanions.     

Valenzisomerisierung von cis-dienonen IV. Die vier stereoisomeren Formen von 4-Methyl-6-phenyl-3, 5-hexadien-2-on

(Z,Z)-4-Methyl-6-phenyl-3,5-hexadien-2-one ( 5 ) is converted to its (Z,E)-isomer 6 at 35° in the dark. This ready, uncatalysed cis,trans-isomerization is shown to proceed through 2H-pyran 9 . Irradiation of either stereoisomeric dienone 6, 7 or 8 at 0° produces a photostationary mixture of 5, 6, 7 and 8 in which the (Z,Z)-isomer 5 predominates.     

Kristallstruktur von Hexamincyclotriphosphazen,P3N3(NH2)6

Crystal Structure of Hexamine Cyclotriphosphazene, P₃N₃(NH₂)₆ In the presence of KNH₂ hexamine cyclotriphosphazene semi ammoniate (molar ratio 12:1) in NH₃ gives crystals of solvent free P₃N₃(NH₂)₆ within 5 d at 130°C and p(NH₃) = 110 bar. The structure was solved by X-rax methods: P₃N₃(NH₂)₆: P2₁/c, Z = 4, a = 10.889(6) Å, b = 5.9531(6) Å, c = 13.744(8) Å, β = 97.83(3)°, Z(F_o) = 1 721 with (F_o)² ≥ 3σ(F_o)², Z(var.) = 157, R/R_w = 0,036/0,041 The structure contains columns of molecules P₃N₃(NH₂)₆ all in the same orientation. The six-membered rings within one molecule have boat conformation. The columns are stacked together in a way that one is surrounded by four others shifted by half a lattice constant in direction [010]. Strong hydrogen bridge-bonds N? H…?N connect molecules within the columns and between them.     

Effects on Coordination of Thioether Sites. 4. Structural Analysis of η3-Tripodal Ligand Manganese(I) Complexes

Crystal 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(F_o) = 0.068, R_w(F_o) = 0.055 for 3617 reflections with I_o > 2σ(I_o). 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, P2_l, R(F_o) = 0.050, R_w(F_o) = 0.037 for 1760 reflections with I_o > 2σ(I_o). 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(F_o) = 0.048, R_w(F_o) = 0.039 for 2973 reflections with I_o > 2σ(I_o). 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.     

Herstellung von Dihydro-, Tetrahydro- und Hexahydrochelidamsäure-Derivaten

Preparation of dihydro-, tetrahydro- and hexahydro-chelidamic-acid derivatives. Three methods for the preparation of 4-oxo-2,6-piperidine-dicarboxylic acid ( 3 ) and derivatives, required as a synthon for betalaine pigments, were explored. The best method was found to be the catalytic hydrogenation of chclidamic acid ( 1 ) with 5% Rh/Alox in water under 2.7 atm. H₂ for 33 h at 70° and subsequent esterification with methanol which gave 42% of cis, cis-4-hydroxy-2,6-piperidine- ( 7 ) and 10% of 2,6-cis-piperidine-dicarboxylic acid dimethyl ester ( 8 ), readily separable by chromatography. Oxidation of 7 with dimethylsulfoxide and a carbodiimide attached to a polymer afforded 90% of 4-oxo-2,6-cis-piperidine-dicarboxylic acid dimethyl ester ( 19 ). Other methods of oxydizing 7 to 19 were less successful. The electrochemical reduction of 1 followed by esterification with methanol led in a low yield to a mixture of 4-oxo-0-2,6-trans-piperidine-dicarboxylic acid dimethylester ( 24 ), its dimethyl acetal 25 and presumably trans-4-hydroxy-r-2, cis-6-piperidine-dicarboxylic acid dimethyl ester ( 26 ). Reaction of 4-oxo-hepta-2E, 5E-dienoic acid ( 35 ) with aqueous ammonia gave a 98% yield of a 3 : 2 mixture of cis- and trans-ammonium-4-oxo-2, 6-piperidine-dicarboxylate ( 39 and 40 ). The above mentioned catalytic hydrogenation method was also applied to N-ethyl-chelidamic acid ( 16 ) to give a 4:6 mixture of the N-ethyl derivatives 17 and 18 . Furthermore, a number of functional derivatives of 5 , of 19 , of 39 and of 40 were prepared. Oxidation of the hydroxy-diester 7 with dimethylsulfoxide and a carbodiimidc derivative in the presence of trifluoroacetic acid afforded 4-oxo-1,2,3,4-tetrahydro-2, 6-pyridine-dicarboxylic acid dimethyl ester ( 50 ). This ester was also obtained under the same conditions from thc keto-diester 19 .     

Synthese und Chiralität von (5S, 6R)-5,6-Epoxy-5,6-dihydro-β,β-carotin und (5R, 6R)-5,6-Dihydro-β,β-carotin-5,6-diol,einem Carotinoid mit ungewöhnlichen Eigenschaften

Synthesis and Chirality of (5S,6R)-5,6-Epoxy-5,6-dihydro-β,β-carotene and (5R,6R)-5,6-Dihydro-β,β-carotene-5,6-diol, a Compound with Unexpected Solubility Characteristics Wittig-condensation of azafrinal ( 1e ) with the phosphorane derived from 7 leads to a (1:3)-mixture of (E)-9′- and (Z)-9′-β,β-carotene-diol 3 , from which pure and optically active 3 ((5R,6R)-5,6-dihydro-β,β-carotene-5,6-diol) has been isolated as bright violet leaflets, m.p. 168°. Due to the trans-configuration of the diol moiety and to severe steric hindrance, hydrogen bonding is reduced to such an extent, that 3 behaves much more as a hydrocarbon than as a diol. There is good evidence that the so-called ‘β-oxycarotin’ obtained by Kuhn & Brockmann [15] by chromic acid oxidation of β, β-carotene is the corresponding racemic cis-diol. 3 has been converted into (5S, 6R)-5,6-epoxy-5.6-dihydro-β,β-carotene ( 4 ), m.p. 156°. This transformation establishes for the first time the chirality of a caroteneepoxide (without other O-functions). Full spectral and chiroptical data including a complete assignement of ¹³C-chemical shifts for azafrin methyl ester and 3 are presented.     

On Triazoles. XXXII. The reaction of 5-amino-1 H-1,2,4-triazolylcarbothiohydrazides with β- and γ-oxo-esters

5-Amino-lH-1,2,4-triazolylcarbothiohydrazides gave β and γ-oxo-esters in boiling ethanol [1,2,4]triazolo- [1,5-d][1,2,4,6]tetrazepine-5-thiones 3 . Analogously ethyl 2-oxocyclohexanecarboxylate provided a mixture of two diastereomeric spiro derivatives 5 and 6 . At 130°, 2-acetonyl-5-methyl-4,5-dihydro-1,3,4-oxadiazole-5-thione ( 8 ) was formed. Ring closure of 3e (R¹ = CH₃, R² = CH₂CH₂COOEt, Q = morpholino) lead to the isomeric pyrrolo[2,1-g][1,2,4]triazolo[1,5-d][1,2,4,6]tetrazepin-8(11H)-one ( 12 ) and pyrrolo[1,2-f][1,2,4]triazolo-[1,5-d][1,2,4,6]tetrazepin-10(7H)-one ( 13 ) derivatives representing two new ring systems.     

Beiträge zum thermischen Verhalten von Sulfaten. III. Zum Hochtemperaturverhalten von CdSO4

Contributions to the Thermal Behaviour of Sulfates. III. The Behaviour of CdSO₄ at High Temperature The behaviour of CdSO₄ was studied by means of high temperature Guinier photographs in the temperature range of 20 to 960°C. Except N-CdSO₄ which is the thermodynamically stable modification at STP, there are 3 high temperature modifications (M, H1 and H2-CdSO₄) of which only metastable M-CdSO₄ can be obtained kineticly stable at room temperature. The lattice constants and the structure type of H1- and H2-CdSO₄ were determined. The structure of H1-CdSO₄ is closely related with that of N-CuSO₄ but in difference of N-CuSO₄ it has a superlattice. H1-CdSO₄ crystallizes orthorhombic with a_325°C = 17.80 Å, b_325°C = 7.35 Å, c_325°C = 4.84 Å, Z = 8.H2-CdSO₄ crystallizes hexagonal with a_850°C = 5.01 Å, c_850°C = 7.64 Å, Z = 2 in a modified NaKSO₄ structure type (space group P 3 m 1) with Cd²⁺ only in the Na⁺ positions. The temperatur and sequence of transitions as well as the thermal expansion of N- and M-CdSO₄ was determined     

Beiträge zum Koordinationsverhalten von Oxidionen in anorganischen Feststoffen. IV [1] Darstellung,Kristallstruktur und spektroskopische Charakterisierung von NiP4O11 und CaNiP2O7

Synthesis, Crystal Structures, and Spectroscopic Characterization of NiP₄O₁₁ and CaNiP₂O₇ From melts single crystals of NiP₄O₁₁ and CaNiP₂O₇ have been grown. These allowed refinement of the crystal structures (NiP₄O₁₁: C1¯, Z = 8, a = 12, 753(4)Å, b = 12.957(3)Å, c = 10.581(4)Å, α = 89.42(2)°, β = 116.96(2)°, γ = 90.20(2)°, R1 = 0.027, wR2 = 0.072 for 3058 I_o > 2σ (I_o), 3291 independent reflections, 290 parameters; CaNiP₂O₇: P1¯, Z = 2, a = 6.433(3)Å, b = 6.536(4)Å, c = 6.515(2)Å, α = 66.4(2)°, β = 87.5(2)°, γ = 82.7(2)°, R1 = 0.026, wR2 = 0.062 for 1624 I_o > 2σ (I_o), 2189 independent reflections, 101 parameter) and measurement of polarized electronic absorption spectra in the uv/vis/nir region (6000—32000 cm^—1). NiP₄O₁₁ is isotypic to the series of ultraphosphates MP₄O₁₁ (M = Mn, Fe, Co, Cu, Zn, Cd) that exhibit a two‐dimensional network formed from ten‐membered phosphate rings. CaNiP₂O₇ completes the series of diphosphates AMP₂O₇ (A: Ca, Sr, Ba; M = Cr — Zn) and is isotypic to CaCoP₂O₇. Ni²⁺ ions in both phosphates show distorted octahedral coordination. The electronic transitions associated with the chromophores [Ni²⁺O₆] are nicely reproduced by calculations within the framework of the angular overlap model (AOM). The parametrisation scheme leads to e_{σ, norm}(2.0Å) = 3690 cm^—1 and B = 896 cm^—1 (C/B = 4.2) for CaNiP₂O₇ and e_{σ, norm}(2.0Å) = 4150 cm^—1 and B = 948 cm^—1 (C/B = 4.5) for NiP₄O₁₁ (Δ_o(CaNiP₂O₇) = 6800 cm^—1; Δ_o(NiP₄O₁₁) = 7100 cm^—1).     

Verbindungen des Germainums und Zinns. 17. Alkylarylstannylen-Komplexe des Chroms und Molybdäns ohne Donorstabilisierung

Compounds of Germanium and Tin. 17 [1]. Alkylarylstannylene Complexes of Chromium and Molybdenum without Donor Stabilization Reaction of the complexes [(OC)₅M(THF)], M = Cr, Mo, with the alkylarylstannylene RR′Sn: R = 2,4,6-tBu₃C₆H₂, R′ = CH₂C(CH₃)₂-3,5-tBu₂C₆H₂, provides the donor-free stannylene complexes [(OC)₅Cr?SnRR′] ( 6 ) and [(OC)₅Mo?SnRR′] ( 8 ), respectively. The X-ray structure analyses of the isotypic compounds 6 and 8 reveal the three coordinate tin atoms in strictly planar environments and acute CSnC angles of 91.2° ( 6 ) and 91.3° ( 8 ).