Sandwich compounds triple decker

The only complex containing a complete cyclopentadienyl ring sandwiched between 2 metal atoms that has been the subject of an X-ray crystallographic study is the triple-decker sandwich compound... 

A. Salzer, and H. Werner, A New Route to Triple-Decker Sandwich Compounds, Angew. Chem. Int. Ed. Engl. 11, 930-932 (1972). 

There has been considerable interest in the synthesis of polymers such as structure (6) in which aromatic rings and metal atoms alternate, due to the possibility of building extended electron-delocalized organometallic polymer chains. However, such a multiple decker polymer has not yet been synthesized, and only a few triple decker-sandwich compounds such as tris( 5-cyclopentadienyl)dinickel cation and tris-(cyclooctatetraene)dititanium dianion have been reported10. ... 

Although recent reviews of metal-carborane electrochemistry (37, 38) obviate the need to discuss multimetallic carborane clusters here, it seems appropriate to mention the results of studies on triple-decker sandwich compounds. The only structurally confirmed (39) all-hydrocarbon tripledecker, [Ni2Cp3] (18), has apparently not been investigated electro-chemically, but carborane analogues containing two or three boron atoms... 

Mass spectra of the pentaarsacyclopentadienyl analogue of ferrocene, 178, and the corresponding triple-decker sandwich compound 179 have been reported . The mass spectrum of 178 exhibits a molecular ion and fragment ions formed by the loss of two or four As atoms. No molecular ion peak was found for 179, but the presence of (M —CpFe) , CjMejFeASj", CpFe and As was in agreement with the prescribed structure of this compound. 

Triple-decker sandwich compounds [e.g. (17)] have been prepared and characterized which contain the planar ligand, analogous toCsH". ... 

Jemmis, E.D. and Reddy, A.C. (1988) Electronic stmcture of triple-decker sandwich compounds with P5, P6,... 

A trinuclear Co2Sn species was obtained while treating 316 with GpCo(C2H4)2. This compound 317 can be viewed as an extremely slipped 34 VE triple-decker sandwich compound (see COMC (1995) and COMC (1982)), as it contains a bridging 1,2,4-triphospholyl 77 -bonded to one and 7] -bonded to the other CpCo unit (Equation (50)). ... 

Serendipitous insertion of CsHs- into the metallaborane Cp 2Cr2B4Fl8 gave the triple-decker sandwich 122 in low yield.140 This compound can be described as an eight-vertex Cr2C2B4 c/ara-metallacarborane cluster, and its preparation is notable as one of the few examples of metallacarborane synthesis from a metallaborane precursor (rather than by the usual metal insertion into a carborane), an approach first demonstrated by Grimes and co-workers in the 1970s.34,141,141a... 

Following the preparation of 4.79, a number of other cyclic mercury crown compounds have been synthesised, which do exhibit halide complexation behaviour. Compound 4.80, forms a 1 1 polymer with bromide in the solid state in which the Hr anions perch above the Hg3 plane. The Hg—Br distances of 3.07-3.39A are considerably longer than normal Hg—Br covalent bonds (about 2.54A).61 The compound also binds SCN- with similarly long bonds as shown in Figure 4.34.60 The analogous chloride complex has a 3 2 stoichiometry suggesting a triple-decker sandwich of type [4.80 Cl 4.80 Cl 4.80]2. ... 

Fig. 6. Triple-decker sandwich complexes having 30-34 valence electrons. (Compound 27 has 34 28 and 30, 30 and 29, 33 valence electrons.)...

Support for this step was obtained by us in experiments where M was shown to add directly to bis(arene)metal complexes to give M2L2 (45, 46). Maximum nuclearity and stability of these species depends on the element, atom deposition rate, temperature and the type of arene. Mono-alkyl and -silyl substituted arenes give compounds that are unstable above 0 C. On the other hand, single crystals of a related triple-decker sandwich of mesitylene and chromium have been obtained (47),... 

Cyclic triene (nonaromatic) and tetraene reactions form a series of new complexes. While some cyclotrienes yield mostly unstable species, heating or hgand trapping can generally lead to stable, isolable compounds. Hydrogen transfer also plays an important role in the synthesis ofrf-rf sandwich complexes. With cot and Cr atoms a Ci Cr bonded Cr2(CgH8)3 complex is formed, while in the case of Ti-cot, a novel Triple Decker Sandwich is obtained. ... 

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