Mechanism of Eliminations over Solid Catalysts

✍ Scribed by Prof. Dr. H. Noller

• Publisher: John Wiley and Sons
• Year: 1968
• Tongue: English
• Weight: 259 KB
• Volume: 7
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.196802322

✦ Synopsis

In the series Cr(C0)5X, [Cr(CO)5X]-, Cr2(CO)loX, and [Crz(CO)loX]-(X = CN, SCN, or OCN) [3,6,71 the pseudohalogen of the binuclear complexes is in the bridge position, as is iodine in the iodine derivatives. Like [Cr(CO)sNCS]-, Cr(C0)5NCS is an isothiocyanate compound with a Cr-N bond [41. MO compounds can be synthesized from cyanometalates( 0) 181 as well as from pure dicyclopentadienylcomplexes(x-C~H~)~M (M = V, Cr, Fe, Co, or Ni) and mixed cyclopentadienylmetalcarbon monoxide complexes [9,101. Particular mention may be made of the preparation of the trigonal-bipyramidal Fe(C0)Ztripy from [(rr-C5H5)Fe(C0)2]2 and 2.2': 6',2"terpyridyl (tripy) [11J. Whereas Co2(CO)8 disproportionates with Lewis bases to CorI and Car-, the compounds [CoI(bipy)3l [Co-I(CO)d] and [CoI(phen)3] [Co-I(CO)4] C121

are formed on treatment of (C~H&COZ(CO)~ (C6Hg = 1,3cyclohexadiene) with 2,2'-bipyridyl (bipy) or 1,lO-phenanthroline @hen). respectively. However, the norbornadiene in (nor-C7H8)2C02(C0)4 can be replaced according to the equation: these being the first cobalt carbonyl derivatives to be obtained in which four CO groups are replaced by N or P ligands [12J ; they have the same structure as Co2(CO)8. The compounds Co2(CO)4L2 are oxidized by I2 to the covalent pentacoordinated ICo(CO)2L, but are reduced by sodium to the salt-like tetracoordinated Na[Co(C0)2L] [12J.