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The diphosphaazide complex (Mes*NPP)Nb(N[Np]Ar)3 (Mes* = 2,4,6-tri-tert-butylphenyl, Np = neopentyl, Ar = 3,5-Me2C6H3), 1, has previously been reported to lose the P2 unit upon gentle heating, to form (Mes*N)Nb(N[Np]Ar)3, 2. The first-order activation parameters for this process have been estimated here using an Eyring analysis to have the values Delta H(double dagger) = 19.6(2) kcal/mol and Delta S(double dagger) = -14.2(5) eu. The eliminated P2 unit can be transferred to the terminal phosphide complexes P[triple bond]M(N[(i)Pr]Ar)3, 3-M (M = Mo, W), and [P[triple bond]Nb(N[Np]Ar)3](-), 3-Nb, to give the cyclo-P3 complexes (P3)M(N[(i)Pr]Ar)3 and [(P3)Nb(N[Np]Ar)3](-). These reactions represent the formal addition of a P[triple bond]P triple bond across a M[triple bond]P triple bond and are the first efficient transfers of the P2 unit to substrates present in stoichiometric quantities. The related complex (OC)5W(Mes*NPP)Nb(N[Np]Ar)3, 1-W(CO)5, was used to transfer the (P2)W(CO)5 unit in an analogous manner to the substrates 3-M (M = Mo, W, Nb) as well as to [(OC)5WP[triple bond]Nb(N[Np]Ar)3](-). The rate constants for the fragmentation of 1 and 1-W(CO)5 were unchanged in the presence of the terminal phosphide 3-Mo, supporting the hypothesis that molecular P2 and (P2)W(CO)5, respectively, are reactive intermediates. In a reaction related to the combination of P[triple bond]P and M[triple bond]P triple bonds, the phosphaalkyne AdC[triple bond]P (Ad = 1-adamantyl) was observed to react with 3-Mo to generate the cyclo-CP2 complex (AdCP2)Mo(N[(i)Pr]Ar)3. Reactions of the electrophiles Ph3SnCl, Mes*NPCl, and AdC(O)Cl with the anionic, nucleophilic complexes [(OC)5W(P3)Nb(N[Np]Ar)3](-) and [{(OC)5W}2(P3)Nb(N[Np]Ar)3](-) yielded coordinated eta(2)-triphosphirene ligands. The Mes*NPW(CO)5 group of one such product engages in a fluxional ring-migration process, according to NMR spectroscopic data. The structures of (OC)5W(P3)W(N[(i)Pr]Ar)3, [(Et2O)Na][{(OC)5W}2(P3)Nb(N[Np]Ar)3], (AdCP2)Mo(N[(i)Pr]Ar)3, (OC)5W(Ph3SnP3)Nb(N[Np]Ar)3, Mes*NP(W(CO)5)P3Nb(N[Np]Ar)3, and {(OC)5W}2AdC(O)P3Nb(N[Np]Ar)3, as determined by X-ray crystallography, are discussed in detail. 相似文献
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Gerung H Bunge SD Boyle TJ Brinker CJ Han SM 《Chemical communications (Cambridge, England)》2005,(14):1914-1916
A convenient, simple, single-source solution synthesis of Ge nanocrystals via thermal reduction of Ge(II) precursor Ge[N(SiMe3)2]2 in a non-coordinating solvent at 300 degrees C and 1 atm Ar is described. 相似文献
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The first isolable cyclogermylidenide salt 2 has been synthesized and isolated by facile dehalogenation of the N-heterocyclic chlorogermylene 1 with elemental potassium in ether and isolated in the form of yellow crystals in 33% yield. Single-crystal X-ray diffraction analysis revealed that 2 crystallizes as a dimeric half-sandwich complex of aromatic C3NGe rings interconnected via intermolecular Ge(II)-->K dative bonds. Its yield can be improved up to 42% by gentle reduction of 1 (or its related GeCl3 complex 8) using potassium graphite. Additionally, the remarkable K2Ge4 cluster compound 9 has been isolated as a side product which consists of an unusual dianionic Ge4 core with parallelogram configuration and pronounced aromaticity as indicated by highly negative NICS values. 相似文献
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The reaction of 2-pyrrolidino-1-aza-1-cycloheptene with aryl isocyanates leads, via 1,4-dipolar cycloaddition, to 1,3-diaryl-10a-pyrrolidinoperhydro[1,3,5]triazino[1,2-a]azepine-2,4-diones. The reaction provides a facile route to the novel [1,3,5]triazino[1,2-a]azepine ring system. 相似文献
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Photodehydrocyclization of 1-phenyl-2-/2-arylethenyl/-3,3-dialkyl-3H-indolium cations leads in very good yield to 7H-indolo[1,2-a]quinolinium cations. 相似文献
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Schnepf A 《Chemical communications (Cambridge, England)》2007,(2):192-194
The reaction of the metastable high temperature molecule GeCl synthesized via a co-condensation technique with LiSi(SiMe(3))3 leads to a metalloid Ge(10)Si cluster compound, in which the arrangement of the germanium atoms can be seen as a cutout from the structure of elemental germanium. 相似文献
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David W. Aldous 《Journal of solid state chemistry》2008,181(11):3033-3036
A new hybrid vanadium (III) fluoride [C4H12N2]3[V7F27] has been synthesised solvothermally. The crystal structure (trigonal, R3¯c; a=17.367(2) Å, c=19.604(2) Å) reveals an unusual and novel chain motif consisting of pyrochlore-like heptameric units of corner-sharing octahedra, which are further linked into linear chains of alternating triple and single octahedral groups. The chains are separated by hydrogen-bonded piperazinium moieties. Magnetic susceptibility data show moderate antiferromagnetic interactions but no long-range order above 2 K, consistent with pronounced one-dimensional character, as well as frustration arising within the triangular units of magnetic ions in the chains. 相似文献
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A tetramer of nine-atom deltahedral germanium clusters and charge 8-, [Ge9=Ge9=Ge9=Ge9]8- , has been characterized as a (Rb-18C6)(+) salt (18C6 = 18-crown-6 polyether). The clusters are connected by pairs of parallel bonds, and the electrons are delocalized over the whole anion. The size of the tetramer is of nanorod dimensions, ca. 2 nm. 相似文献
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Synthesis and conformational study of 1,3,2-oxazaphosphorino[4, 3-a]isoquinolines: a new ring system
Martinek T Forró E Günther G Sillanpää R Fülöp F 《The Journal of organic chemistry》2000,65(2):316-321
A set of 1,3,2-oxazaphosphorino[4,3-a]isoquinolines 6a,b-9a,b, a new ring system, was synthesized, and their stereochemical and conformational analyses were performed by (1)H, (13)C, and (31)P NMR methods. X-ray measurements were also carried out to confirm the stereochemical assignments and conformational results obtained by means of NMR. Intermediate coupling constants (3)J(P,H) were found for compounds 7 and 9; these do not relate to equilibria between previously reported conformers, but are indicative of new distorted conformational states in solution. The connecting isoquinoline and the steric interaction between the aromatic moiety and the Me-1 substituent can block the oxazaphosphorinane ring. The conformational behavior of compounds 6 and 8 was characterized by the usual chair-twist equilibrium. 相似文献
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The layered nitride Sr11Ge4N6 contains Ge4- Zintl anions in both [Sr4Ge]4+ layers and [GeN2Sr7]4+ antiperovskite-type slabs which are separated by sheets of bent [Ge(II)N2]4- ions; the observed range of formal germanium oxidation states in nitrides thus extends between +4 and -4. 相似文献
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[reaction: see text] Oxidation of phthalahydrazide (1) with lead tetraacetate in the presence of furfural (3a) in methylene chloride gives [5,6]benza-3a,7a-diaza-3-carboxylindane-4,7-dione-1-ene (7a) in 64% yield. 5-Methylfurfural (3b) also reacted similarly to give the product 7b in 46% yield. Reaction of phathalazine-1,4-dione with thiophene-2-carboxaldehyde gives N-(2-formylthiophene)phthalahydrazide. 相似文献
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Alkylation of p-tert-butylcalix[5]arene 1c with an excess of 2-(2-chloroethoxy)ethyl tosylate 2 and anhydrous K2CO3, has led to the serendipitous regioselective formation of cone-in (1,2-3,5)-calix[5]arene bis-crown-3 derivative 4 possessing a reactive 2-(2-chloroethoxy)ethoxy pendant functionality at the lower rim. The structure and conformation of 4 have firmly been assigned by a combination of NMR analysis and HF/6-31G∗ ab initio calculations, as well as by an independent stepwise synthesis. A preliminary ESI-MS screening of the binding properties of 4 toward alkali metal ions has shown a clear preference for the larger cations. 相似文献
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[Ge2]4− Dumbbells with Very Short Ge−Ge Distances in the Zintl Phase Li3NaGe2: A Solid‐State Equivalent to Molecular O2
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Lavinia M. Scherf Prof. Dr. Antti J. Karttunen Dr. Oliver Pecher Dr. Pieter C. M. M. Magusin Prof. Dr. Clare P. Grey Prof. Dr. Thomas F. Fässler 《Angewandte Chemie (International ed. in English)》2016,55(3):1075-1079
The novel ternary Zintl phase Li3NaGe2 comprises alkali‐metal cations and [Ge2]4? dumbbells. The diatomic [Ge2]4? unit is characterized by the shortest Ge?Ge distance (2.390(1) Å) ever observed in a Zintl phase and thus represents the first Ge=Ge double bond under such conditions, as also suggested by the (8?N) rule. Raman measurements support these findings. The multiple‐bond character is confirmed by electronic‐structure calculations, and an upfield 6Li NMR shift of ?10.0 ppm, which was assigned to the Li cations surrounded by the π systems of three Ge dumbbells, further underlines this interpretation. For the unperturbed, ligand‐free dumbbell in Li3NaGe2, the π‐ bonding py and pz orbitals are degenerate as in molecular oxygen, which has singly occupied orbitals. The partially filled π‐type bands of the neat solid Li3NaGe2 cross the Fermi level, resulting in metallic properties. Li3NaGe2 was synthesized from the elements as well as from binary reactants and subsequently characterized crystallographically. 相似文献