Hydroxo Hydrido Complexes of Iron and Cobalt (Sn−Fe−Sn, Sn−Co−Sn): Probing Agostic Sn⋅⋅⋅H−M Interactions in Solution and in the Solid State
✍ Scribed by Jörg J. Schneider; Jörg Hagen; Norbert Czap; Carl Krüger; Sax A. Mason; Robert Bau; Jürgen Ensling; Philipp Gütlich; Bernd Wrackmeyer
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 226 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
Bis(toluene)iron 9 reacts with Lapperts stannylene [Sn{CH(SiMe 3 ) 2 } 2 ] (4) to form the paramagnetic bis-stannylene complex [{(h 6 -toluene)FeÀSn-[CH(SiMe 3 ) 2 ] 2 } 2 ] (10). Compound 10 reacts with H 2 O to form the hydroxo hydrido complex [(h 6 -C 7 H 8 )(m-OH)(H)-FeÀ{Sn[CH(SiMe 3 ) 2 ] 2 } 2 ] (12) in high yield; its solid-state structure has been elucidated by X-ray and neutron diffraction analysis. In agreement with the 1 H NMR results, 12 contains a hydridic ligand whose exact coordination geometry could be determined by neutron diffraction. The 1 H and 119 Sn NMR analysis of 12 suggested a multicenter Sn/Sn/H/Fe bonding interaction in solution, based on significantly large values of J(Sn,H,Fe) 640 AE 30 Hz and J( 119 Sn, 119 Sn) 4340 AE 100 Hz. In solution, complex 12 exists as two diaster-eomers in a ratio of about 2:1. Neutron diffraction analysis has characterized 12 as a classical metal hydride complex with very little Sn ´´´H interaction and a typical FeÀH single bond (1.575( 8) ). This conclusion is based on the fact that the values of the Sn ´´´H contact distances (2.482(9) and 2.499(9) ) are not consistent with strong FeÀH ´´´Sn interactions. This finding is discussed in relation to other compounds containing MÀH ´´´Sn units with and without strong three-center interactions. The neutron diffraction analysis of 12 represents the first determination of a SnÀH atomic distance employing this analytical technique. The cobalt analogues [(h 5 -Cp)(m-
15, which are isolobal with 12, were prepared by the reaction of [(h 5 -Cp)CoÀSn{CH(SiMe 3 ) 2 } 2 ] ( 14) with H 2 O and D 2 O, respectively. The magnitude of J(Sn,H) (539 Hz) in 15 is in the same range as that found for 12. The molecular structure of 15 has been determined by X-ray diffraction which reveals it to be isostructural with 12. The coordination geometries of the Co(Fe)-Sn1-O-Sn2 arrangements in 12 and 15 are fully planar within experimental error. Compounds 10 and 15 are rare examples of fully characterized complexes obtained as primary products from water activation reactions.