Uracil is coordinated via its deprotonated N1; 6-methylthiouracil acts as a bidentate ligand via N1 and S. Analogously, xanthine is a monodentate ligand bound by its deprotonated N7, while 6-mercaptopurine seems to bind in a bidentate fashion via N7 and S. Reaction a generates three carbon and one phosphorus stereogenic centers while reactions b and c each produce four carbon and one phosphorus chiral centers.
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In dichloromethane, all three reactions proceeded smoothly at room temperature giving the corresponding rigid diphosphines in high yields. Two-dimensional ROESY NMR studies confirmed that the prolonged reaction time required for reaction c is due to several major repulsive interactions between the chiral naphthylamine auxiliary and the Z -methyl-substituted vinylphosphine in the transition state. Nevertheless, all three reactions gave the corresponding rigid diphosphine in high yields. The absolute stereochemistries of the three bidentate phosphine ligands that were produced from the cycloaddition reactions have been assigned by 2D ROESY NMR spectroscopy.
These diphosphines are powerful sequesterers of group 8 metals although they are highly air-sensitive in the free ligand form. The synthesis and isolation of the hypobromite CF3OBr is reported. The hypobromite was separated from the solid by high-vacuum condensation onto a cold surface and characterized by matrix isolation multichannel Raman spectroscopy. An ab initio calculation was performed, and a force field and the torsional barrier of CF3OBr were calculated.
The calculation predicts an eclipsed conformation with a rotional barrier of 3. The photolytic decomposition of CF3OBr in the solid state and in an argon matrix was investigated. The syntheses, characterizations, and X-ray crystallographic structure determinations are described for adducts of stable nucleophilic carbenes with pnictinidenes. The adducts between 1,3-dimesitylimidazolylidene and phenylphosphinidene, phenylarsinidene, trifluoromethyl phosphinidene, and pentafluorophenyl arsinidene are reported.
The synthesis and structure of the adduct between 1,3-dimesitylimidazolinylidene and phenylphosphinidene from the reaction of 1,3-dimesitylimidazolinylidene with phenylphosphorus dichloride are also reported. The 31P NMR shifts of the phosphorus adducts suggest strongly shielded phosphorus centers in accord with the polarized structures.
Electrochemical investigation revealed the existence of ReVI and ReVII analogues, which were hydrolytically unstable in aqueous solution but which were isolated as crystalline tetra-n-butylammonium and tetra-n-heptylammonium salts, respectively, from nonaqueous solvents. Attempts to prepare selenium-rich species resulted in the formation of elemental selenium or Se3N2Cl2. Each molecule was found to lie in an approximate half-chair conformation that is well established for 1,3-S4N2 i. The bond parameters agree well with experimental information where available.
Reviews in Inorganic Chemistry
Whereas the lengths of the bonds in the NEEEN fragment approach those of the single bonds, the bonds in the NEN fragment show marked double bond character. The stabilities of the molecules decrease expectedly with increasing selenium content as judged by the total binding energy at the MP2 level of theory. Within a given chemical composition, isomers containing a N Se N unit lie higher in energy than those containing a N S N unit. These results may explain why selenium-rich SexS4-xN2 molecules have not been isolated.
This report concerns the carrier properties of [Mn acacen ]-derived compounds toward polar organometallics, inorganic ion pairs, and salts. The use of 8, which has a chiral bridge across two nitrogen atoms, did not lead to a significant asymmetric induction in the reaction with PhCHO, because of the long separation between the lithium cation and the stereogenic center. Their reaction with 1 appears to depend on the steric bulkiness of the alkyl group in NaOR, resulting in either monomeric adducts, i.
All the dimeric units reported in this paper show a slight antiferromagnetic coupling between the two Mn II assisted by bridging alkoxo groups. ULM crystallizes in the orthorhombic system space group Pmca, No. Its structure, solved by single-crystal X-ray diffraction, results from isolated single [FeF HPO4 2]2-n chains of the tancoite type, with diprotonated amines inserted in between.
All terminal hydrogens are involved in hydrogen bridges to oxygen atoms of the crown ether molecules. Consistent with this connectivity pattern, analysis of the magnetic data reveals competing ferromagnetic and antiferromagnetic exchange interactions within the tetranuclear core structure. Both ESR and magnetic data indicate a singlet ground state for 1.
In addition, the general magnetic behavior of oxovanadium IV clusters is discussed on the basis of classification schemes derived from simple binuclear fragmentation patterns. The nature of the product formed is influenced both by the i reducing power of NaBH4, which is controlled by the volume and concentration of the borohydride and the reaction pH, and ii the degree of condensation of the tungstate ions, which is controlled by the reaction pH.
Although the reducing power of NaBH4 increases with decreasing pH, an increasing degree of condensation of the tungstate tends to lower the degree of reduction in many instances.
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The tungsten bronzes undergo interesting crystal-chemical changes with the temperature of heating. Of note, the intermolecular exchange with free Me2SO on 4 takes place exclusively from a conformational isomer of 4 structure 4. These species were expected to undergo thiocarboxylic anhydride elimination to give stoichiometric metal sulfides and remove the organic supporting ligands cleanly. The spectroscopic and analytical data were consistent with the formulas identified above, and in the solid state the compounds are monomeric with approximate tetrahedral metal coordination environments and monodentate S-bond thiocarboxylate ligands.
Thermal decomposition of these compounds in the solid state or in solution resulted in formation of the corresponding metal sulfide at low temperatures, as seen by powder X-ray diffraction. Evidence for thiocarboxylic anhydride elimination was documented by NMR in solution phase reactions. These preliminary reactivity studies have revealed the great potential of this highly tailorable chemical system as precursors to group 12 metal sulfido species.
FIFTY YEARS OF DEVELOPMENT OF INORGANIC CHEMISTRY IN THE SOVIET UNION - IOPscience
Pair your accounts. Your Mendeley pairing has expired. Please reconnect. May 1, Volume 36, Issue 10 Pages In this issue: Share. Sort By: Page Date Articles. Hockless Boujemaa Moubaraki Keith S. Rabe Glenn P. Yap Arnold L.
Powell Bryan D. Fischer Markus M. Schulte Eberhardt Herdtweck Mike R. Abstract Full text PDF ABSTRACT Within the transition metal oxide systems, vanadium presents a unique chemistry due to its capacity to form a great number of mixed-valence oxo clusters which often have the peculiarity to incorporate species that function, for size, shape, and charge, as templates. Jegier David A. Herbst-Irmer K. Paula M. Marques Carlos F.
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Gardner Linda L. Kuehnert James M. Wilker Karen E. Wetterhahn Stephen J. Brunold Hans U. Organometallic Selenolates. Abstract Full text PDF ABSTRACT Starting from mono- and bifunctional ferrocene-based tris 1-pyrazolyl borates, a novel route to oligonuclear complexes is presented, which incorporates transition metal centers differing substantially in their chemical nature. Beer Andrew R. Graydon Anna O. Johnson David K. Asymmetric Synthesis of P-Chiral Diphosphines. Andy Hor S. Selvaratnam K. Mok Andrew J. White David J. Would you like to change to the United States site? Stephen J.
Lippard Editor. Undetected location. NO YES. Home Subjects Chemistry Inorganic Chemistry. Progress in Inorganic Chemistry, Volume Selected type: E-Book. Added to Your Shopping Cart. View on Wiley Online Library.
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