trans-RuCl2 [kappa(3)-1R,2R-P(NH)(NH)P](PPh3) was synthesized and used in the oxidation of cyclohexene at 80-130degreesC by molecular oxygen with very high activity to the products including 2-cyclohexen-1-one, 2-cyclohexen-1-ol and 1,2-cyclohexandiol. The addition of carbon nanotubes (CNTs), which were synthesized by Fe-Cu/SiO2 catalyzed decomposition of ethylene at 550 degreesC, can enhance the activity of the Ru complex and the selectivity of 2-cyclohexen-1-ol. It was also better for the recycling of the Ru complex, the catalytic activity and selectivity of which still held at a high level after nine times using. (C) 2002 Published by Elsevier Science B.V.