CYCLIZATION OF PHENYLPROPIOLIC ACID ON TITANOCENE. SYNTHESIS AND MOLECULAR STRUCTURE OF DI-η5-CYCLOPENTADIENYL(CINNAMYLATO-C3,O)TITANIUM/PHENYLPROPIOLIC ACID (1/1), A NOVEL TITANACYCLE, SYNTHESIS OF DICYCLOPENTADIENYLBIS(PHENYLPROPIOLATO)TITANIUM

Article abstract of DOI:10.1016/0022-328X(86)80254-6

Dimethyltitanocene reacts with phenylpropiolic acid under hydrogen and with the assistance of light to yield the dark red titanium(IV) compound <5-C5H5)2C6H5C=CH-COO>*C6H5C<*>CCOOH>.X-ray structure analysis showed the unit cell to be composed of a titanocene metallacycle in which titanium is η⁵-bonded to two cyclopentadienyl rings and to one carbon and one oxygen atom in a 5-membered metallacycle , the whole molecule being in a 1/1 hydrogen bonded association with phenylpropionic acid.The complex crystallizes in the monoclinic space group P2₁/c with unit cell paramaters a 12.435(4), b 13.046(4), c 14.326(5) Angstroem, β 92.50(4) deg, and D_c 1.34 g cm^-3 for Z=4.Least-squares refinement based on 1812 independent observed reflections led to a final R value of 0.079.Reaction of dimethyltitanocene with phenylpropiolic acid in toluene gives the compound <(η⁵-C5H5)2Ti(OOC-C<*>C-C6H5)2> as an air stable orange crystalline solid.