Metal Atom Synthesis of (h6-Toluene)(h2-ethene)iron(s1-stannanediyls): Unusual Iron(0) Complexes.
In: Journal of the American Chemical Society (J.Am.Chem.Soc.), Jg. 121 (1999) ; Nr. 6, S. 1409-1410
Zeitschriftenaufsatz / Fach: Chemie
A multistep direct reaction sequence was developed starting from iron vapor and toluene, which reacted with ethene gas and then with Lappert's or Weidenbruch's stannylenes SnR2 (R = CH(SiMe3)2 or 2-tert-butyl-4,5,6-trimethylphenyl), to form the title compds. 5 and 6 in good yields. This direct metal vapor approach offers a valuable synthetic pathway to a new class of 18e mixed arene iron/tin half-sandwich complexes (arene)Fe(SnR2)(ethene). 5 Irreversibly reacts with an excess of CO gas at -20 DegC in toluene soln. by substitution of both ethene and arene ligands forming the two stable complexes Fe(CO)3(SnR2)2 and Fe(CO)4SnR2 (R = CH(SiMe3)2) in a 1:1 ratio. If only 1 equiv of CO is added at -20 DegC, only ethene is selectively substituted and stable red crystals of (h6-C6H5Me)Fe(CO)SnR2 (R = 2-tert-butyl-4,5,6-trimethylphenyl) are formed in nearly quant. yield. Under the right conditions mixed Fe(0)/Sn(II) group metal 18e complexes can be moderately stable but still reactive enough to allow arene reactivity under very mild, yet unexpected conditions.