Complex sandwich

Complexes containing two cyclic polyolefinic ligands will be included in this section if one of the rings is cyclopentadienyl. 

Sandwich Complexes.—INDO-SCF-MO calculations have been performed for a variety of sandwich systems of the type CpML with L = ( / -C3H3), ( -C4H4), Cp, or (j/ -CaHy), - and the results have been 

The ability of the CpCo(r) -CiH system to stabilize a carbocation lias been demonstrated by the synthesis of the stable salt (i7 -C4Ph4)Co(jy -QH4)CPh2 (PFe-).  

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Classic A/-heterocychc ligands, eg, bipyridyl (bipy), terpyridyl, imidazole, pyrazine, phenanthroline, piperazine (including alkyl- and aryl-substituted derivatives), and polypyrazol-l-yl-borates (bis, tris, and tetra), have all been found to coordinate Th(IV) chlorides, perchlorates, and nitrates. The tripodal hydrotris(pyrazolyl)borates, HBPz, have been used to stabilize organometaHic complexes (31). Bis-porphyrin Th(IV) "sandwich" complexes have been... 

MetaHacarborane dicarboUide complexes are generaUy more robust than the corresponding cyclopentadiene complexes. The bis-dicarboUide sandwich complexes of general formula [M(C2Bg)H )2] , where M is Fe ", Co ", and exhibit great thermal, chemical, redox, and radiolytic stabUity. 

When the reaction is carried out in the presence of NaCsHs the purple mixed sandwich complex (83) is obtained ... 

Even more intriguing are the double sandwich complexes which feature and -As3 ... 

The half-sandwich and sandwich complexes of phospholides and phosphole tetramer are known even for the nontransition metals. The half-sandwich arrangement was studied for lithium tetramethylphospholide [89AG(E)1367] and sodium derivative 127 generated from the phospholide tetramer and sodium in the presence of 1,2-dimethoxyethane [94JA3306 96AG(E)1125]. Potassium and 1,2-dimethoxyethane in THE in these conditions give a full dianionic sandwich 128. 

When the iron sandwich complex bears an arene substituent with at least one benzylic hydrogen, the acidity of the latter is enhanced by the 7t-complexation to the 12e fragment FeCp+. The pKa of the conjugate acid of superoxide radical... 

In the context of pyridin synthesis from alkynes and nitriles homogeneously catalyzed by (cyclopentadienyl)cobalt complexes (Eq. 13), it was found that electron-withdrawing groups on the cyclopentadienyl ring significantly increase the activity [63]. During the screening of various cobalt half-sandwich complexes... 

The remarkable 19-electron molybdenum half-sandwich complex Mo(r 5-C5HPh4)(CO)2L2 (L2 = 2,3-bis(diphenylphosphino)maleic anhydride) (44) was prepared from [Mo(r)5-C5HPh4)(CO)3]2 and L2 and its structure in the solid state determined [65]. The average distance from molybdenum to the ring ligand is... 

Metal sandwich complexes of cyclic, planar and pyramidal ligands containing boron. R. N. Grimes, Coord. Chem. Rev., 1979, 28, 47-96 (132). 

Electron rich half-sandwich complexes — metal bases par excellence. H. Werner, Angew. Chem., Int. Ed. Engl., 1983, 22, 927-949 (170). 

Sandwich complexes nickel. 5, 35 Sapphyrins, 2, 888 demetallation, 2, 891 metallation, 2, 891 reactions, 2, 891 synthesis, 2, 889 Sarcoplasmic reticulum calcium/magnesium ATPase, 6, 566 skeletal muscle... 

The entrapment of lithium oxide and lithium halides by the lithium amidinate Li[Bu"C(NBu02] has been studied in detail by X-ray crystallography Interesting polycylic molecular structures have been obtained, as exemplified by the unusual sandwich complex of lithium oxide made from Li[Bu C(NBu )2l in toluene... 

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