EFFECT OF LIGAND DONOR-ACCEPTOR PROPERTIES ON SELECTIVITY OF CATALYTIC OLEFIN ISOMERIZATION REACTION

Isomerization reaction of hex-1-ene, 1,5-hexadiene and 1,7-octadiene, catalyzed by HRh(CO) (PPh(3))(3) and HRh(PPh(3))(4) at 40 degrees C ha ve been studied. Hex-1-ene undergoes total conversion to hex-2-ene at presence of both of catalysts used, whereas isomerization of dienes is catalysed by HRh(CO)(PPh(3))(3) complex only. To explain observed dif ferences in catalyst activity, theoretical calculations for model stru ctures of [HRh(CO)(3)(hexadiene)] (I) and [HRh(PH3)(3)(hexadiene)] (II ), by Fenske-Hall method have been done. The calculations allowed eluc idation of the isomerization reaction course which depends on electron density distribution in rhodium-olefin complex as well as on the way of olefin coordination to the rhodium.