نتایج جستجو برای: inner transition elements

تعداد نتایج: 602988  

Journal: :Inorganic chemistry 2004
Paul J Dyson Andrew K Hearley Brian F G Johnson Patrick R R Langridge-Smith J Scott McIndoe

A variety of homonuclear and heteronuclear transition metal carbonyl clusters have been analyzed by ultraviolet laser desorption/ionization time-of-flight mass spectrometry. The spectra were recorded in negative and positive ion modes, using both linear and reflective techniques. A range of different clusters based on different nuclearities, geometries, and ligand types, which include hydrides,...

Journal: :Physical review letters 2004
Marc Smits C A de Lange Albert Stolow D M Rayner

We report on the strong field ionization of small transition metal clusters (nickel, Ni(n) n=1-36) within the quasistatic regime at an infrared wavelength of 1.5 microm and at intensities up to 2 x 10(14) W/cm(2). From ion yields in a constant axial intensity beam, we obtained saturation intensities for the individual Ni(n) clusters. As compared to quasistatic, single active electron calculatio...

2013
Grégory Landelle Armen Panossian Sergiy Pazenok Jean-Pierre Vors Frédéric R Leroux

In the last few years, transition metal-mediated reactions have joined the toolbox of chemists working in the field of fluorination for Life-Science oriented research. The successful execution of transition metal-catalyzed carbon-fluorine bond formation has become a landmark achievement in fluorine chemistry. This rapidly growing research field has been the subject of some excellent reviews. Ou...

Journal: :Organic & biomolecular chemistry 2012
Manoj Kumar Naresh Kumar Vandana Bhalla

A new thiacalix[4]arene-cinnamaldehyde derivative 3, which undergoes red shift in the fluorescence spectrum in the presence of Ag(+) ions, has been synthesized. This emission shift is attributed to the intramolecular charge transfer process in the presence of Ag(+) ions with a detection limit in the nanomolar range.

Journal: :Physical review letters 2007
D W Shen B P Xie J F Zhao L X Yang L Fang J Shi R H He D H Lu H H Wen D L Feng

The charge density wave (CDW) is usually associated with Fermi surfaces nesting. We here report a new CDW mechanism discovered in a 2H-structured transition metal dichalcogenide, where the two essential ingredients of the CDW are realized in very anomalous ways due to the strong-coupling nature of the electronic structure. Namely, the CDW gap is only partially open, and charge density wave vect...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1976
L Pauling

In complexes of the transition metals containing clusters of metal atoms the cobalt-cobalt bond lengths are almost always within 1 pm of the single-bond value 246 pm given by the enneacovalent radius of cobalt, whereas most of the observed iron-iron bond lengths are significantly larger than the single-bond value 248 pm, the mean being 264 pm, which corresponds to a half-bond. A simple discussi...

2017
Yi-Ting Hsu Abolhassan Vaezi Mark H Fischer Eun-Ah Kim

Theoretically, it has been known that breaking spin degeneracy and effectively realizing spinless fermions is a promising path to topological superconductors. Yet, topological superconductors are rare to date. Here we propose to realize spinless fermions by splitting the spin degeneracy in momentum space. Specifically, we identify monolayer hole-doped transition metal dichalcogenide (TMD)s as c...

Journal: :Organic & biomolecular chemistry 2016
Thomas J Thomas Benjamin A Merritt Betsegaw E Lemma Adina M McKoy Tri Nguyen Andrew K Swenson Jeffrey L Mills Michael G Coleman

Copper(i) N-heterocyclic carbene (CuNHC) complexes are more catalytically active than traditional transition metal salts for the cyclopropenation of internal alkynylsilanes and diazoacetate compounds. A series of 1,2,3-trisubstituted and 1,2,3,3-tetrasubstituted cyclopropenylsilane compounds were isolated in good overall yields. An interesting regioselective and chemodivergent reaction pathway ...

Journal: :The Journal of organic chemistry 2005
Anna Torrent Iván González Anna Pla-Quintana Anna Roglans Marcial Moreno-Mañas Teodor Parella Jordi Benet-Buchholz

[reaction: see text] Nitrogen-containing 15-membered triacetylenic macrocycles known as 1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-triynes (1) and enediynic macrocycles called 1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3-ene-8,13-diynes (4 and 5) were satisfactorily prepared. [2+2+2] cycloisomerization processes catalyzed by transition metals were tested in the abov...

Journal: :Chemical communications 2015
Sébastien Dhers Jean-Pierre Costes Philippe Guionneau Carley Paulsen Laure Vendier Jean-Pascal Sutter

Rare cases of genuine (i.e. field-free) SMM have been found for mixed 3d-4f-5d ring-shaped compounds with Tb(III) (Ueff/kB = 23.0 K) or Dy(III) (Ueff/kB = 26.4 K). The ferromagnetic interactions between the transition metals are shown to play an essential role in this feature.

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