Abstract
It is shown that [Ru(H2O)6]2+ can efficiently catalyse under mild experimental conditions the dimerisation of ethylene in a fully aqueous solution to form butenes ([Z-but-2-ene] : [E-but-2-ene] : [but-1-ene] is 1 : 2.2 : 2.2); the reaction intermediates [Ru(CH2 CH2)(H2O)5](tos)2 and [Ru(CH2 CH2)2(H2O)]4(tos)2 have been isolated in solid form.