In the field of organometallic chemistry, the X-ray structure of ferrocene initiated scientific studies of sandwich compounds, while that of Zeise's salt stimulated research into " back bonding " and metal-pi complexes.
22.
A close relative that does have sufficient reactivity, obtained by reaction of uranocene with uranium borohydride is the half-sandwich compound ( COT ) U ( BH 4 ) 2 discovered in 1983 by the group of M . J . Ephritikhine.
23.
Nevertheless, the observation led Wilkinson and F . Albert Cotton to attempt the synthesis of rhodocenium and iridocenium Nobel Prize for Chemistry " for their pioneering work, performed independently, on the chemistry of the organometallic, so called sandwich compounds ".
24.
The compound [ ( thf ) 3 Ca { ?-C 6 H 3-1, 3, 5-Ph 3 } Ca ( thf ) 3 ] also described in 2009 is an inverse sandwich compound with two calcium atoms at either side of an arene.
25.
The term " sandwich compound " was introduced in organometallic nomenclature in during the mid-1950s in a report by J . D . Dunitz, L . E . Orgel and R . A . Rich, who confirmed the structure of ferrocene by X-ray crystallography.
26.
Nuclear magnetic resonance ( NMR ) is the most applied tool in the study of metal sandwich compounds and organometallic species, giving information on nuclear structures in solution, as liquids, gases, and in the solid state . 1 H NMR chemical shifts for diamagnetic organotransition-metal compounds is usually observed between 25 and 40 ppm, but this range is much more narrow for diamagnetic metallocene complexes, with chemical shifts usually observed between 3 and 7 ppm.
27.
The shockingly novel sandwich structure, [ Fe ( ? 5-C 5 H 5 ) 2 ], was deduced and reported independently by three groups in 1952 : Robert Burns Woodward and Geoffrey Wilkinson investigated the reactivity in order to determine the structure and demonstrated that ferrocene undergoes similar reactions to a typical aromatic molecule ( such as benzene ), Ernst Otto Fischer deduced the sandwich structure and also began synthesising other metallocenes including cobaltocene; Eiland and Pepinsky provided Nobel Prize for Chemistry " for their pioneering work, performed independently, on the chemistry of the organometallic, so called sandwich compounds ".
