| | 61 | Author
| Wolfgang Dörrscheidt, Herbert Schäfer | Requires cookie* | | | Title
| Die Struktur der Phase BaNi2Si2 und ihre Verwandtschaft zum ThCr2Si2 -Strukturtyp The Structure of BaNi2Si2 and its Relationship to the ThCr2Si2 Structure  | | | | Abstract
| The new compound BaNi2Si2 crystallizes in the orthorhombic system, space group Cmcm-D^ with a — 650 ± 1 pm, b = 535 ± 1 pm, c = 1133 ± 2 pm. The structure can be interpreted as a distorted variant of the ThCr2Si2-type. Von den Verbindungen der Erdalkalimetalle (A) mit Übergangselementen (T) und Halbmetallen der IV. Hauptgruppe (X) wird bei der Zusammenset-zung AT2X2 meistens der ThCr2Si2-[1-4], in seltenen Fällen der CaBe2Ge2-Strukturtyp [5] ausgebildet. Beide sind ternäre Besetzungsvarianten der BaAL*-Struktur. In der neuen, im folgenden beschriebenen Verbindung BaNi2Si2 wurde nun erstmals eine Ver-zerrungsvariante dieser Struktur aufgefunden. Darstellung und Charakterisierung Zur Darstellung der Verbindung wurde ein stöchio-metrisches Gemenge der Elemente im Korundtiegel unter Argonatmosphäre */2 h auf 1700 K erhitzt, 2 h bei 970 K getempert und dann über Nacht auf Raumtemperatur abgekühlt. Der Schmelzpunkt wurde zu 1058 ± 10 K bestimmt. Die Verbindung fiel in Form unregelmäßig begrenzter, plättchen-förmiger Kristalle an, die sich an feuchter Luft lang-sam mit einem weißen, porösen Belag überzogen. Zur analytischen Charakterisierung wurden die zur Strukturbestimmung verwendeten Kristalle mit einer Mikrosonde vermessen. Die Stöchiometrie stützt sich weiterhin auf eine vollständige Röntgen-strukturanalyse an Einkristallen. Strukturbestimmung Zur röntgenographischen Charakterisierung wur-den von einem plättchenförmigen Kristall Weißen-berg-(CuKa) und Precession-Aufnahmen (MoKa) angefertigt, aus denen die Gitterkonstanten und -Symmetrien abgeleitet wurden (Tab. I). Danach kristallisiert die Verbindung orthorhombisch mit den Interferenzbedingungen Reflexe (hkl) nur vorhanden für h-{-k = 2n und Reflexe (hOl) nur vorhanden für l = 2n. Danach sind die Raumgruppen Cmcm-D.^, Cmc2i-C2v und Ama2-C2® möglich. | | | |
Reference
| Z. Naturforsch. 35b, 297—299 (1980); eingegangen am 1. November 1979 | | | |
Published
| 1980 | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0297.pdf | | | | Identifier
| ZNB-1980-35b-0297 | | | | Volume
| 35 | |
| 62 | Author
| Klaus-Peter Frank, Joachim Strähle, Johann Weidlein | Requires cookie* | | | Title
| Darstellung, Schwingungsspektrum und Kristallstruktur des Decabromo-J«-nitrido-ditantalats(V) Ta2NBrJö« A Complex with a Symmetrical Ta=N=Ta Bridge | | | | Abstract
| Ein Komplex mit symmetrischer Ta=N = Ta-Briicke Preparation, Vibrational Spectra and Crystal Structure of the Deca Bromo ^-Nitrido Ditantalate(V) Ta2NBri0 3 ~. Decabromo(/z-nitrido)ditantalate(V), Preparation, IR Spectra, Crystal Structure The salt (NH4)3Ta2NBrx0 can be prepared from NH4Br und TaBr5 at 400 °C in a sealed glas ampoule. The greenish yellow substance, which is sensitive to moist air, crystallizes in the tetragonal space group P4/mnc with Z — 2. The crystal structure is closely related to that of K4M2OC1IO • H20 (M = Ru, Re). It is built up by NH4+ cations and Ta2NBri0 3 --anions. The anions possess the point symmetry D4h and therefore show a symmetrical Ta = N = Ta bridge. The Ta-N distances of 185 pm can be interpreted by double bonds. Im Rahmen unserer Untersuchungen über Metall-Nitridhalogenide interessierten wir uns auch für Um-setzungen zwischen Ammoniumhalogeniden und Metallhalogeniden, die häufig zu Metallnitridhalo-geniden oder Metallnitriden führen. Unter anderem wird über die Bildung von NbNCl2 [1] und TaNCl2 [2, 3] aus NH4CI und den entsprechenden Penta-chloriden berichtet. Wir haben die gleichen Reak-tionen durchgeführt [4], konnten die Bildung der Nitridhalogenide jedoch nicht reproduzieren. Viel-mehr wurde festgestellt, daß NbCls im angegebenen Temperaturbereich zu (NH4)NbCl6 reagiert und ab 500 °C mit überschüssigem NH4C1 zum (NH4)2NbCl6 reduziert wird. Bei höheren Temperaturen entsteht dann NbN. Im Falle des TaCls beobachteten wir ebenfalls zunächst die Bildung des Hexachloro-komplexes NH4TaCl6, der dann oberhalb 600 °C zum Nitrid des fünfwertigen Tantals TaßNö am-monolysiert wird, ohne daß die Zwischenstufe TaNCl2 beobachtet wird [4], Die Reaktion zwischen den Bromiden NH4Br und TaBrs führt nach Angaben von Glushkova et al. [5] unter Reduktion des Tantals bei 325 °C zu | | | |
Reference
| Z. Naturforsch. 35b, 300—306 (1980); eingegangen am 14. Dezember 1979 | | | |
Published
| 1980 | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0300.pdf | | | | Identifier
| ZNB-1980-35b-0300 | | | | Volume
| 35 | |
| 63 | Author
| Jochen Ellermann, Leo Mader | Requires cookie* | | | Title
| Chemie polyfunktioneller Liganden, 57 [1] | | | | Abstract
| Über Iridium(I)-und Platin(II)-Komplexe des Bis(diphenylphosphino)amins und die oxidative Addition kleiner Moleküle an Di[bis(diphenylphosphino)amin-P.P']iricUum(I)-chlorid Chemistry of Polyfunctional Ligands, 57 [1] About Iridium (I) and Platinum(II) Complexes of Bis(diphenylphosphino)amine and the Oxidative Addition of Small Molecules to Di[bis(diphenylphosphino)amine]iridium(I)-chloride Iridium(I) Complexes, Platinum(II) Complexes, Bis(diphenylphosphino)amine, Vibrational Spectra R2PNHPR2 (1) (R = C6H5) reacts with [(//-Cl)Ir(C8Hi2)]2 in a molar ratio of 4:1, to give the square planar, ionic complex [Ir(R2PNHPR2)2]Cl (2a). By reaction of 2a with NaBR4, [Ir(R2PNHPR2)2]BR4 (2 b) is obtained. Treatment of 2 a with CO gives [Ir(CO)(R2PNHPR2)2]C1 (3a). The complex 3a is also formed by the reaction of 1 with Ir(CO)(PR3)2Cl (R = C6H5) and Ir(CO)2(jo-H2N-C6H4-CH3)Cl. 3a undergoes metathesis with NH4PF6 to yield [Ir(CO)(R2PNHPR2)2]PF6 (3b). The N-deuterated derivative [Ir(CO)(R2PNDPR2)2]Cl (4) is made by H/D exchange from 3a with CH3OD. Oxidative additions of 02, CS2, I2 and (SCN)2 to 2a yield [Ir(02)(R2PNHPR2)2]Cl (5), [Ir(j?2.CS2)(R2PNHPR2)2]Cl (6), [Ir(I)2(R2PNHPR2)2]Cl (7) and [Ir(SCN)2(R2PNHPR2)2]Cl (8). Additionally K2[PtCl4] and 1 reacts to [Pt(R2PNHPR2)2]Cl2 (9). The new compounds are characterised, as far as possible, by their IR, FIR, Raman and 31 P NMR spectra. | | | |
Reference
| Z. Naturforsch. 35b, 307—315 (1980); eingegangen am 8. Oktober 1979 | | | |
Published
| 1980 | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0307.pdf | | | | Identifier
| ZNB-1980-35b-0307 | | | | Volume
| 35 | |
| 64 | Author
| Eberhard Hohaus, Wolfgang Riepe, Klaus Wessendorf, La | Requires cookie* | | | Title
| Massenspektrometrische Untersuchungen an Borchelaten, V [1] Fragmentierung borhaltiger aromatischer Azoverbindungen Mass Spectrometric Investigation of Boron Chelates, V [1] Fragmentation of Aromatic Azo Compounds Containing Boron M+ M+-R M+-RH A M+-C6H5N2 C6H5N2+ C6H5 + | | | | Abstract
| Differing fragmentation of boron chelates of aromatic azo compounds confirms the structural formulae la-7c, presented in [2]. More significant differences are caused by the substituent of the boron R (F instead of C6H5). Although certain rules can be deduced by the substitution of F for CeHs with regard to the change in intensity of the ions M+, M+-R (and others), in some cases the stable aromatic azo system causes a significant change in the fragmentation as compared with that of azomethine chelates. The chelates 7 eliminate "RH" and show no molecular ion. Apparently a second chelate ring is closed before further fragmentation can start. Fragmentation of 7 a and b is analogous to 5. Einführung Die Massenspektrometrie nimmt bei der analyti-schen Überprüfung und der Konstitutionsaufklä-rung von Borchelaten eine besondere Stellung ein, weil umfangreiches Material mit verschiedensten Komplexbildnern vorliegt. Deshalb werden die Er-gebnisse der Azochelate [2] mit denen der früher dargestellten verglichen. Die Numerierung der Che-late erfolgt nach dem Formelschema in [2]. Vergleich der Fragmentierungen Chelate 1 und 2: Das Massenspektrum von la zeigt nur eine geringe relative Intensität für das Tab. I. Nr. | | | |
Reference
| Z. Naturforsch. 35b, 316—318 (1980); eingegangen am 8. Oktober 1979 | | | |
Published
| 1980 | | | |
Keywords
| Mass Spectrometry, Boron Azo Chelates, Fragmentation | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0316.pdf | | | | Identifier
| ZNB-1980-35b-0316 | | | | Volume
| 35 | |
| 65 | Author
| Boron Chelates, BoronMetal Chelates, Eberhard Hohaus, Klaus Wessendorf | Requires cookie* | | | Title
| Borchelate und Bormetallchelate, VI [1] Zur Bildung von Borchelaten aromatischer Azoverbindungen | | | | Abstract
| Bidentate chelate reagents incorporating a suitable group (e.g. OH, NH2) in ortho position to the azo-group react with diphenylboronic acid anhydride or boron trihalides (BF3, BCI3) resulting in the BR2-six membered ring-chelates of types 1 and 2. The products of the reaction of tridentate chelate reagents with phenylboronic acid or boron trifluoride at elevated temperature are BR-chelates with two six membered rings (types 3 and 4). The conditions of the formation of the bicyclic chelates 5 and 6 depend on the position of the substituents of the chelate reagents. The incorporation of only one BR2 group is possible if the order of the substituents in 2,2'-dihydroxyazobenzenes is not symmetrical (chelates of the type 7). Structural isomers of boron chelates of the types 5, 6 or 7 with Na/N/S isomerism have not yet been observed. The identification of the structures of the above-mentioned complexes was achieved by means of iH, n B and 19 F NMR and IR spectroscopy. For mass spectrometric analysis see ref. [2]. Einführung Azomethine des Salicylaldehyds sind mit Bor-verbindungen leicht zu Chelaten umzusetzen [3-5]. Die ähnlich strukturierten Azo-Chelate sind da-gegen kaum [6] beschrieben worden. Folgende Aspekte führten zu den Synthesen der Borchelate: In den Chelaten 1^1 ist das Bor an dasjenige N-Atom der Azogruppe gebunden, dessen Koordination zu einem (Typ I und 2) oder zwei Chelat-6-Ringen (3 und 4) führt. Im Gegensatz zu 1-4 sind bei 5-7 die Bindungsverhältnisse der ko-ordinativen B-N-Bindung unklar. Von besonderem Interesse waren die Umsetzungen mit unsym-metrisch substituierten 2.2'-Dihydroxyazobenzolen, da die Bildung strukturisomerer Chelate (Na/N^-Isomerie) erwartet werden konnte. Ein weiterer Aspekt war die Farbvertiefung bei der Chelatbildung, die quantitative Bestimmungen | | | |
Reference
| Z. Naturforsch. 35b, 319—325 (1980); eingegangen am 21. Dezember 1979 | | | |
Published
| 1980 | | | |
Keywords
| Boron Chelates, Azo Compounds, NMR, IR | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0319.pdf | | | | Identifier
| ZNB-1980-35b-0319 | | | | Volume
| 35 | |
| 66 | Author
| Werner Liese, Kurt Dehnicke, Jürgen Pebler | Requires cookie* | | | Title
| AsPh4)2[Re2FN2Cl7], ein w-Fluoro-Nitridokomplex des Rhenium(VI) (AsPh4)2[Re2FN2Cl7], a ^a-Fluoro Nitrido Complex of Rhenium(VI | | | | Abstract
| ,u-Fluoro Nitrido Complex of Rhenium(VI), Preparation, IR, Magnetic Moment (AsPh4)2[Re2FN2Cl7] is prepared by the reaction of ReNCLi with AsPh4F in acetonitrile solution. The IR spectrum indicates a bridging Re-F-Re complex anion with terminal Re = N ligands. The magnetic susceptibility was measured in the temperature range of 4.8-280 K. The effective magnetic moment is 1.66 B.M. per Re atom (0 = —0.5 K) and corresponds well w T ith Re(VI). The magnetic moment of the well known PPh4[ReNCl4] has also been studied {juett = 1.67 B.M.; 0 = —1.2 K). Wir berichteten unlängst über die Darstellung und die Kristallstruktur von ReNCl4, dem ersten Nitridhalogenid des siebenwertigen Rheniums [1], Das Nitridchlorid hat eine dem isoelektronischen W0C14 [2] ähnliche Kolumnarstruktur mit alter-nierend langen Re=N-Re-Bindungen, die als Drei-fach-Einfachbindungen zu deuten sind. Die Chemie des ReNCl4 ist durch eine ausgeprägte Tendenz zur Ausbildung des Re(VI)-Zustandes charakterisiert. Hierzu sind bereits Lewis-Basen wie POCI3, Cl~ oder N3 -befähigt, die nach (1-3) mit ReNCl4 unter Redox-Reaktion reagieren: 4 ReNCl4 + 6 P0C13 -> [ReNCla • P0C13]4 • 2 P0C13 + 2 Cl2 (1) ReNCl4 + CI--> [ReNCl4]-+ 1/2 Cl2 (2) ReNCl4 + N3--> [ReNCl4]-+ 11/2 N2 (3) Im folgenden berichten wir über die Einwirkung von Fluoridionen auf ReNCl4. Hier läßt die ausge-prägte Eigenschaft des F-Liganden zur Brücken-bildung linear verknüpfte Rheniumkomplexe er-warten. Darstellung und Eigenschaften von (AsPh4) 2 [Re2FN2Cl7] Der Komplex entsteht bei der Vereinigung ge-kühlter Lösungen von ReNCl4 und Tetraphenyl-arsoniumfluorid in Acetonitril. Bereits nach kur-zer Zeit entsteht ein orangeroter, feinkristalliner, im trockenen Zustand nicht nennenswerter hygro-skopischer Niederschlag der Zusammensetzung (AsPh4)2[Re2FN2Cl7]. Man isoliert den Komplex | | | |
Reference
| Z. Naturforsch. 35b, 326—328 (1980); eingegangen am 3. Oktober/14. November 1979 | | | |
Published
| 1980 | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0326.pdf | | | | Identifier
| ZNB-1980-35b-0326 | | | | Volume
| 35 | |
| 67 | Author
| M. P. Berthet, H. Vincent, Y. Monteil | Requires cookie* | | | Title
| A New Preparation of S4N4 | | | | Abstract
| Pure S4N4 is prepared by a new method from reduction of S3N3CI3 by various metals (Hg, Cu, Sn). Realized either in an inert solvent or directly in gaseous phase the reaction is complete. The stability range of NSC1 has been determined by Raman spectrometry. Tetrasulfur tetranitride is a very interesting product because it is the starting material for many products containing sulfur and nitrogen. In the usual method S4N4 (1) is prepared by bubbling gaseous ammonia through a solution of sulfur di-chloride dissolved in an inert solvent: 16 NH3 + 6 SCls -> S4N4 + 12 NH4C1 + 2 S Besides S4N4, NH4C1 and S, the S7NH imine is also formed in small quantity. NH4CI is easily eliminated by iced water. The separation of S4N4 from the obtained mixture is difficult. The three compounds (S4N4, S7NH and S) have similar molecular struc-tures (puckered eight-membered rings), they have similar solubilities in solvents and are difficult to separate from one another. The extraction of S4N4 by dioxane permits to partly eliminate sulfur. S4N4 can be purified by chromatography on an alumina column (2), benzene, a good solvent for S4N4, is used for its elution. By sublimation under vacuum it is possible to eliminate sulfur from S4N4, but this method is dangerous due to the explosive character of S4N4. The methods of purification are long and not always very efficient. For the first time, we have prepared S4N4 in a high purity grade from S3N3CI3 which can be easily obtained (3). This new method consists in the action of reducing metals such as Hg, Cu or Sn on S3N3CI3 either in an inert solvent or directly in gaseous phase. The identification and the stability of the different gaseous compounds have been studied by infrared and Raman spectro-scopy. | | | |
Reference
| Z. Naturforsch. 35b, 329—331 (1980); received September 17/November 16 1979 | | | |
Published
| 1980 | | | |
Keywords
| Tetrasulfur Tetranitride Synthesis, Thiazyl Halogenide Decomposition, Metal Reaction, Monothiazyl Chloride Stability, IR Spectra | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0329.pdf | | | | Identifier
| ZNB-1980-35b-0329 | | | | Volume
| 35 | |
| 68 | Author
| J. Schmachtel, Hk Müller-Buschbaum | Requires cookie* | | | Title
| Oxotitanate mit gemischter Valenz, III Zur Kenntnis von BaTi8016 Oxotitanates with Mixed Valence. III About BaTisOie | | | | Abstract
| The hitherto unknown compound BaTisOi6 was prepared by heating a mixture of Ba0:Ti02 = 1:4 in a vacuum furnace to 1400 °C (Ti crucible). Single crystal X-ray investigations show monoclinic symmetry (a — 1420,9, b = 297,1, c — 998,1 pm, ß = 133,50°; space group C|-C2). The crystal structure was found to be isotypic to a-Mn02. | | | |
Reference
| Z. Naturforsch. 35b, 332—334 (1980); eingegangen am 14. Dezember 1979 | | | |
Published
| 1980 | | | |
Keywords
| Barium, Titanium, Oxide, Crystal Structure, a-Mn02-Type | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0332.pdf | | | | Identifier
| ZNB-1980-35b-0332 | | | | Volume
| 35 | |
| 69 | Author
| Günther Eulenberger | Requires cookie* | | | Title
| Darstellung und Kristallstruktur des Dithallium(I)blei(II)tetrathiogermanats(rV) Tl2PbGeS4 Preparation and Crystal Structure of Dithallium(I) Lead(II) Tetrathiogermanate(IV) | | | | Abstract
| Preparation, Crystal Structure, Thallium Lead Thiogermanate Tl2PbGeS4 was synthetized by fusion of a stoichiometric mixture of T12S, PbS, and GeS2, and prolonged heating of the reaction product. A single crystal could be isolated for intensity measurements on an automated four-circle single crystal diffractometer. Tl2PbGeS4 is monoclinic, space group P2i/a with a = 8.907(2), b= 9.114(2), c= 10.502(3) A,/3 = 94.08(2)°, and Z = 4. The crystal structure was determined by means of standard methods and refined to if= 0.065. The structure is composed of tetrahedral [GeS4] 4_ anions which are held together by Tl 1+ and Pb 2+ cations. The GeS4 tetrahedra are only slightly deformed (mean distance Ge-S: 2.220 A). The Tl atoms are surrounded by eight S atoms at distances ranging from 3.085 to 4.055 A forming irregular coordination polyhedra. The Pb atom is coordinated by six S atoms in a strongly distorted octahedral arrangement at distances varying from 2.803 to 3.256 A. The Pb atoms and the Tl(2) atoms are alternately situated between slabs of GeS4 tetrahedra parallel to the ab plane. The Tl(l) atoms are found within these slabs located between the GeS4 tetrahedra. | | | |
Reference
| Z. Naturforsch. 35b, 335—339 (1980); eingegangen am 17. Dezember 1979 | | | |
Published
| 1980 | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0335.pdf | | | | Identifier
| ZNB-1980-35b-0335 | | | | Volume
| 35 | |
| 71 | Author
| ThomasA. Albright, Peter Hofmann, AngeloR. Rossi | Requires cookie* | | | Title
| A Study of the Bonding and Geometry in Phosphacumulene Ylides | | | | Abstract
| Phosphacumulene Ylides, Molecular Orbital Calculations A series of ab initio molecular orbital calculations have been carried out on phospha-cumulene ylides of the type H3P = C = C = X where X = S, O, CNH, and (OH)2. The variation in the P-C-C bond angle was examined and compared to the experimentally determined structures of analogs. The dominant factor in setting the P-C-C angle was found to be the relative 7r-acceptor capability of the C = X fragment in the plane of the bending motion. Quantitative PMO-arguments were constructed for the X = S, O and (OH)2 cases along this line. It is also shown, that P-C a* character mixes into the highest occupied molecular orbital. The magnitude of this effect is dictated by the amount of bending and this strongly influences the 1 Jp-c nuclear spin coupling constants. Finally, the bending in H3P = C = PH3 was also investigated in a similar manner. | | | |
Reference
| Z. Naturforsch. 35b, 343—351 (1980); received October 5 1979 | | | |
Published
| 1980 | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0343.pdf | | | | Identifier
| ZNB-1980-35b-0343 | | | | Volume
| 35 | |
| 72 | Author
| Il-Hwan Suh, Gabriela Weber, Menachem Kaftory, Wolfram Saenger, Heinz Sieger, Fritz Vögtle | Requires cookie* | | | Title
| Structural Change of a Linear Polyether upon Complex Formation. l.ll-Bis(2-acetylaminophenoxy)-3.6.9-trioxaundecane and its KSCN Complex" | | | | Abstract
| The title compound (1) was crystallized as free ligand and as its (1 • KSCN)2 • H20 complex. Crystallographic data are, for the former: space group C 2/c, a — 31.110(9), b = 4.608(4), c = 17.188(6) A, ß = 105.27(8)°, Z = 2, Dm = 1.25 gem-3 ; for the latter: space group P2i, a = 11.044(3), b = 18.310(4), c = 14.485(4) Ä, ß = 97.49(2)°, Z = 4, Dm = 1.27 gem -3 . Crystal structures were solved by direct methods using X-ray diffrakto-meter data and least squares refinements converged at 10.8% for 1 and at 7.6% for (1 • KSCN)2 • H20. The free ligand (1) is S-shaped and, upon K+-complexation, changes signs of some gauche O-C-C-O torsion angles while C-C-O-C angles remain trans. In (1 • KSCN)2 • H20, there are two complex molecules 1 A • KSCN • H20 (I) and 1 B • KSCN (II). The ligands are wrapped circularly around K + and coordinated with only four of the five polyether oxygens. K+ interacts further with H20 in (I) and with N of SCN~ in II and, in both complexes, with acetylamino oxygen of adjacent 1. The latter interaction leads to polymeric structures not observed previously for similar complexes. | | | |
Reference
| Z. Naturforsch. 35b, 352—359 (1980); received November 28 1979 | | | |
Published
| 1980 | | | |
Keywords
| Polyether, KSCN Complex, Polymer Formation, X-ray | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0352.pdf | | | | Identifier
| ZNB-1980-35b-0352 | | | | Volume
| 35 | |
| 73 | Author
| Friedrich-Wilhelm Grevels, Konrad Schneider, Carl Krüger, Richard Goddard | Requires cookie* | | | Title
| Tricarbonyl(^ 4 -1.5-cümethylen-2.6-cümethylcyclooctan)eisen: photochemische Synthese und Struktur Tricarbonyl(^ 4 -l,5-dimethylene-2,6-dimethylcyclooctane)iron: Photochemical Synthesis and Structure | | | | Abstract
| Extended photolysis of pentacarbonyliron in neat 2,3-dimethylbutadiene results in dimerization of the diene and formation of tricarbonyl(?y 4 -l,5-dimethylene-2,6-dimethyl-cyclooctane)iron (1). The structure of complex 1 is characterized by a trigonal-bipyramidal geometry whereby the exocyclic double bonds of the diene ligand and one of the carbonyl groups lie exactly in the equatorial coordination plane. | | | |
Reference
| Z. Naturforsch. 35b, 360—365 (1980); eingegangen am 5. November 1979 | | | |
Published
| 1980 | | | |
Keywords
| Carbonyliron Olefin Complexes, Dimerization of Dimethylbutadiene, Photochemistry, NMR, X-ray | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0360.pdf | | | | Identifier
| ZNB-1980-35b-0360 | | | | Volume
| 35 | |
| 75 | Author
| Claudia Bäk, Klaus Praefcke | Requires cookie* | | | Title
| und dessen Cycloreversion Organic Sulfur Compounds, XLVII [1] Dimerization of Monothiobenzil to a 1,3-Dithietane and its Cycloreversion | | | | Abstract
| The thermal dimerization of monothiobenzil (lc) to a 1,3-dithietane (2c) and the photochemical cycloreversion of this heterocycle to 1 c is described. | | | |
Reference
| Z. Naturforsch. 35b, 372—375 (1980); eingegangen am 26. November 1979 | | | |
Published
| 1980 | | | |
Keywords
| Heterocycles, Organic Sulfur Compounds, a-Oxothiones, 1, 3-Dithietans, 1, 3-Oxathiols, Photoreactions | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0372.pdf | | | | Identifier
| ZNB-1980-35b-0372 | | | | Volume
| 35 | |
| 76 | Author
| Heinz Falk, Klaus Thirring | Requires cookie* | | | Title
| Beiträge zur Chemie der Pyrrolpigmente, XXXVI [1] Zur anaeroben Photochemie von 21.24 -Diinethy 1 -aetiobiIi verdin -1V -v On the Anaerobic Photochemistry of 21,24-Dimethyl-aetiobiliverdin-IV-y | | | | Abstract
| Photoisomerisation, Selectivity, iH-NMR, UV-VIS 21,24-Dimithylaetiobiliverdin-IV-y was prepared via excessive methylation of aetiobili. verdin-IV-y. Its configuration could be established using 1 H NMR methods. Photoisomeri-sation yields the (E,Z,Z) and (E,Z,E) diastereomers which means that the selectivity observed in photoisomerisation of bilatrienes-abc can be removed by making the ligands of the lactame moiety adjacent to exocyclic double bonds nearly equal. The torsional angles at the methine single bonds are approximatly equal in the three diastereomers resulting in much the same UV-VIS spectra. The obviously strong distortion of the con-jugated chromophor allows for the deceleration of certain radiationless deexcitation paths thereby allowing for photoisomerisations in homogenous solution. | | | |
Reference
| Z. Naturforsch. 35b, 376—380 (1980); eingegangen am 1. November 1979 | | | |
Published
| 1980 | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0376.pdf | | | | Identifier
| ZNB-1980-35b-0376 | | | | Volume
| 35 | |
| 80 | Author
| Albrecht Mewis, Astrid Distler | Requires cookie* | | | Title
| Zur Kenntnis der Verbindungen CaNi2As2, SrNi2As2 und Ca2)3NiU)7As7 | | | | Abstract
| Investigations of the systems Ca(Sr)-Ni-As resulted in the discovery of three ternary phases. CaNi2As2 and SrNi2As2 are isotypic and crys-tallize in the ThCr2Si2-structure (space group 14/mmm) with the following constants: CaNi2As2 a = 406.5(1) pm, c= 994.9(2) pm, SrNi2As2 a = 415.4(1) pm, c = 1029.0(2) pm. Ca2.3Niu.7As7 (0= 940.4(1) pm,c= 381.6(l)pm) crystallizes in a hexagonal lattice; a Zr2Fei2P7-structure is supposed. | | | |
Reference
| Z. Naturforsch. 35b, 391—393 (1980); eingegangen am 26. November 1979 | | | |
Published
| 1980 | | | |
Keywords
| Arsenides, Nickel, Crystal Structure, Calcium, Strontium | | | |
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| default:Reihe_B/35/ZNB-1980-35b-0391_n.pdf | | | | Identifier
| ZNB-1980-35b-0391_n | | | | Volume
| 35 | |
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