Tungsten carbyne complexes containing 1,1′-bis(diphenylphosphino)ferrocene (dppf). Reverse relationship between NMR chemical shifts of the carbyne 13C and the 183W nuclei and molecular structure of WCl(CO)2(dppf)(CPh)

Article abstract of DOI:10.1021/om00016a053

The Fischer-type carbyne complexes containing 1,1′-bis(diphenylphosphino)ferrocene (dppf), WX(CO)₂(dppf)(CR) [X = Cl, R = Me, Ph, thienyl, furyl, and ferrocenyl; X = Br; R = ferrocenyl], were synthesized. In these complexes, an increase in the ¹⁸³W and a decrease in the carbyne ¹³C chemical shifts with increasing π-donating ability of the carbyne substituents were observed. The ferrocenyl-substituted derivate showed the more enhanced redox potential compared with the corresponding carbonyl analog. The structure of WCl(CO)₂)(dppf)(CPh) has been determined by the single-crystal X-ray diffraction method. The crystal is monoclinic with space group P2₁/n, and the cell constants are a = 15.565(3) A?, b = 21.493(4) A?, c = 11.167(2) A?, β = 92.45(1)°, and Z = 4. The structure has been refined to a final R value of 0.052. The coordination geometry around the W atom is octahedral with a cis chelation of dppf. The W-C bond distance [1.82(1) A?] is in the normal range. The Cp rings of the dppf ligand in the complex take a staggered conformation, but all the C atoms in each ring are almost coplanar.