Induction of carbonyl-carbyne coupling by chelating Schiff base ligands. Crystal and molecular structure of carbonyl(methoxyphenylacetylene)bis(pyrrole-2-carboxaldehyde methyliminato)tungsten

Article abstract of DOI:10.1021/om00150a023

Reaction of the tungsten carbyne complexes [(W≡CR)Cl(CO)₂(py)₂] (1a, R = C₆H₅; 1b, R = CH₃) with pyrrole-2-carboxaldehyde methylimine (C₆H₈N₂)/KOH in THF followed by metathesis with NEt₄Cl in CH₂Cl₂ gives the anionic tungsten ketenyl complexes [NEt₄][W(C₆H₇N₂) ₂(RCCO)(CO)] (3a, R = C₆H₅; 3b, R = CH₃). Alkylation of 3 with methyl fluorosulfate provides the neutral tungsten alkoxyacetylene complexes W(C₆H₇N₂)₂(RC≡COCH ₃)(CO) (4a, R = C₆H₅; 4b, R = CH₃). The molecular structure of 4a has been determined by X-ray crystallography: space group P2₁/n, a = 9.568 (2) ?, b = 20.884 (4) ?, c = 10.597 (2) ?, β = 98.25 (2)°, Z = 4, R = 2.8%, R_w = 2.4%.