Chloro-, Bromo-und Jodokomplexe von Kobalt(II) in einigen nichtwäßrigen Lösungsmitteln

The formation of chloro-, bromo-and iodocomplexes of cobalt(II) has been studied mainly by a spectrophotometric investigation in acetonitrile, propanediolcarbonate, trimethylphosphate, dimethylacetamide and dimethylsulfoxide as far as data were not available. The results are discussed with respect to the relative donor properties of solvents and halide ions.     

Koordinationsformen des Eisen(III)-chlorids in Phosphoroxychlorid

Zusammenfassung In den roten Lösungen von Eisen(III)-chlorid in Phosphoroxychlorid ist die Koordinationszahl größer als 4; es liegt gleichzeitig Koordination von Phosphoroxychloridmolekeln und Assoziation der Eisen(III)-chlorideinheiten untereinander vor. Zusatz von Chloridionendonoren führt zur Bildung des Chlorokomplexes. Die maximale Koordinationszahl ist dann 4; darüber hinaus können keine weiteren Chloridionen, FeCl₃-Einheiten oder POCl₃-Molekeln koordiniert werden.Mit 5 AbbildungenZugleich 19. Mitt. der Reihe: Das Solvosystem Phosphoroxychlorid.18. Mitt.:V. Gutmann undF. Mairinger, Mh. Chem.91, 529 (1960).     

Treating singularities present in the Sutcliffe-Tennyson vibrational Hamiltonian in orthogonal internal coordinates

Two methods are developed, when solving the related time-independent Schrodinger equation (TISE), to cope with the singular terms of the vibrational kinetic energy operator of a triatomic molecule given in orthogonal internal coordinates. The first method provides a mathematically correct treatment of all singular terms. The vibrational eigenfunctions are approximated by linear combinations of functions of a three-dimensional nondirect-product basis, where basis functions are formed by coupling Bessel-DVR functions, where DVR stands for discrete variable representation, depending on distance-type coordinates and Legendre polynomials depending on angle bending. In the second method one of the singular terms related to a distance-type coordinate, deemed to be unimportant for spectroscopic applications, is given no special treatment. Here the basis set is obtained by taking the direct product of a one-dimensional DVR basis with a two-dimensional nondirect-product basis, the latter formed by coupling Bessel-DVR functions and Legendre polynomials. With the basis functions defined, matrix representations of the TISE are set up and solved numerically to obtain the vibrational energy levels of H3+. The numerical calculations show that the first method treating all singularities is computationally inefficient, while the second method treating properly only the singularities having physical importance is quite efficient.     

Phenylimino-phosphorsäure-(diäthylamid)-chloride

Zusammenfassung Monomere Phosphinimine der allgemeinen Formel C₆H₅N= =PCl _n (NEt₂)_3-n (n=0,1,2) lassen sich (I) aus dimerem Phenylimino-phosphorsäure-trichlorid und Diäthylamin in Gegenwart eines Chlorwasserstoffakzeptors und (II) durch Reaktion der Phosphine PCl _n (NEt₂)_3-n mit Phenylazid darstellen. Die Phosphorane Et₂NPCl₄, (Et₂N)₂PCl₃ und (Et₂N)₃PBr₂ reagieren mit Anilin nicht zu Phenylimino-Verbindungen. Durch alkalische Hydrolyse von C₆H₅N=PCl(NEt₂)₂ entsteht das Phosphorsäure-bis[diäthylamino]-anilid. Die IR- und¹H- und³¹P-NMR-Spektren der Verbindungen werden mitgeteilt.

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Monomeric phosphinimines of the general formula C₆H₅N= =PCl _n (NEt₂)_3-n (n=0,1,2) are formed (I) from dimeric phenyliminophosphoricacid-trichloride and diethylamine in the presence of a HCl-acceptor and (II) by reacting the phosphines PCl _n (NEt₂)_3-n with phenylazide. The phosphoranes Et₂NPCl₄, (Et₂N)₂PCl₃ and (Et₂N)₃PBr₂ do not give the corresponding phenylimines with aniline. Alkaline hydrolysis of C₆H₅N= =PCl(NEt₂)₂ gives bis[diethylamino]-anilido-phosphinoxid. IR-,¹H- and³¹P-NMR-spectra are given.

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Thermisch stimulierte Lumineszenzerscheinungen. I Einfluß der Vorbehandlung von Kupferstaub und das Phänomen „Kontaktgedächtnis”︁

Thermally Stimulated Luminescence Phenomena. I. Influence of Pretreatment of Copper Dust and the Phenomenon “Contact Memory” The thermally stimulated luminescence of so-called “copper dust” is strongly influenced by its pretreatment. Samples which have been cooled prior to measurement show lower energies and those which have been mechanically treated, irradiated or heated, show higher thermoluminescence energies than samples which have been stored normally. After removal of the samples from the metallic carrier and subsequent heating of the latter, the thermoluminescence energies are proportional to those found for the sample measured immediately before. This phenomenon is considered as “contact memory”. All results are interpreted according to the concept of the hierarchic order.     

Human topoisomerase I poisoning: docking protoberberines into a structure-based binding site model

Summary Using the X-ray crystal structure of the human topoisomerase I (top1) – DNA cleavable complex and the Sybyl software package, we have developed a general model for the ternary cleavable complex formed with four protoberberine alkaloids differing in the substitution on the terminal phenyl rings and covering a broad range of the top1-poisoning activities. This model has the drug intercalated with its planar chromophore between the −1 and +1 base pairs flanking the cleavage site, with the nonplanar portion pointing into the minor groove. The ternary complexes were geometry-optimized and relative interaction energies, computed by using the Tripos force field, were found to rank in correct order the biological potency of the compounds; in addition, the model is also consistent with the top1-poisoning inactivity of berberine, a major prototype of the protoberberine alkaloids. The model might serve as a rational basis for elaboration of the most active compound as a lead structure, in order to develop more potent top1 poisons as next generation anti-cancer drugs.     

Square-Planar Nickel(II) O,O′-Dialkyldithiophosphato Complexes with Triphenylphosphine of the Type [NiX(S2P{OR}2)(PPh3)] (X = Cl,Br, I and NCS)

A series of new [NiX(S₂P{O-c-Hex}₂)(PPh₃)](X = Cl^–, Br^–, I^– and NCS^–)(1)–(4) and [Ni(NCS)(S₂P{OR}₂)(PPh₃)][R =n-Pr (5), i-Pr (6)] complexes has been synthesized and characterized by elemental analyses, f.i.r., i.r., u.v.–vis., ¹H-, ¹³C{¹H}- and ³¹P{¹H}-n.m.r. spectra, magnetochemical and conductivity measurements. A single crystal X-ray analysis of [Ni(NCS)(S₂P{O-n-Pr}₂)(PPh₃)](5) reveals the molecular structure of the complex and confirms a square-planar geometry around the central atom of nickel with the NCS anion coordinated via the nitrogen atom.     

Preparation and chemistry of phosphoranyl-derived iodanes

The preparation and chemistry of novel phosphoranyl-derived lambda(3)-iodanes is reported. The phosphoranyl-derived phenyliodonium sulfonates were prepared in good yields by the reaction of stabilized phosphonium ylides [1-triphenylphosphoranylidene-2-propanone, methyl(triphenylphosphoranylidene)acetate, (triphenylphosphoranylidene)acetaldehyde, and (triphenylphosphoranylidene)acetonitrile] with the pyridinium complex of iodobenzene ditriflate or with [hydroxy(tosyloxy)iodo]benzene under mild conditions. These compounds represent a potentially useful class of reagents that combine in one molecule synthetic advantages of a phosphonium ylide and an iodonium salt. Specifically, phosphorane-derived phenyliodonium tosylates can react with soft nucleophiles, such as iodide, bromide, benzenesulfinate, and thiophenolate anions, with a selective formation of the respective alpha-functionalized phosphonium ylides, which can be further converted to alkenes by the Wittig reaction with benzaldehyde. The phosphoranyl-derived benziodoxoles can be prepared by the reaction of 1-acetoxybenziodoxole with stabilized phosphonium ylides. An unusual ligand exchange on the iodine(III) center resulting in the substitution of a carbon ligand with an oxygen ligand was observed in the reaction of these compounds with strong acids.