Atom and group transfer reactions were found to occur between heterocumulenes and (TTP)Ti(η2-3-hexyne), 1 (TTP = meso-5,10,15,20-tetra-p-tolylporphyrinato dianion). The imido derivatives (TTP)TiNR (R = iPr, 2; tBu, 3) were produced upon treatment of complex1 with iPrNCNiPr, iPrNCO, or tBuNCO. Reactions between complex 1 and CS2, tBuNCS, or tBuNCSe afforded the chalcogenido complexes, (TTP)TiCh (Ch = Se, 4; S, 5). Treatment of complex 1 with 2 equiv of PEt3 yielded the bis(phosphine) complex, (TTP)Ti(PEt3)2, 6. Although (TTP)Ti(η2-3-hexyne) readily abstracts oxygen from epoxides and sulfoxides, the reaction between 1 and OP(Oct)3 did not result in oxygen atom transfer. Instead, the paramagnetic titanium(II) derivative (TTP)Ti[OP(Oct)3]2, 7, was formed. The molecular structure of complex 7 was determined by single-crystal X-ray diffraction: Ti−O distance 2.080(2) Å and Ti−O−P angle of 138.43(10)°. Estimates of TiO, TiS, TiSe, and TiNR bond strengths are discussed.
Available at: http://works.bepress.com/l-woo/10/