Abstract
The protonation of RuH(NO)(Cyttp) resulted in the formation of $[RuH_2(NO)(Cyttp)]^+$ which is characterized as a classical cis-dihydried complex. This complex is fluxional and the intramolecular process involving a molecular hydrogen complex is proposed. This mechanism was further supported by the reactivity of this complex toward neutral 2-electron ligands. On the other hand, it failed to detect the existence of $[RuH_2(NO)(etp)]^+$ probably due to instability of the complex but the crystal structure of $[Ru(PMe_3)(NO)(etp)]^+$ formed by the protonation of RuH(NO)(etp) followed by the addition of $PMe_3$ was determined to have a trigonal bipyramidal structure with a linear NO in the equatorial plane and a facial etp ligand. The crystals are monoclinic, space group P21/n, with unit cell dimensions a = 14.130(2), b = 21.026 (3), c = 14.760 (1) ${\AA}$, ${\beta}$ = 97.88 $(l)^{\circ}$ V = 4344 ${\AA}^3$, Z = 4, R = 0.046 and $R_w$ = 0.056 for the 4779 intensities with $F_o^2 > 3{\sigma}(F_0^2)$ and the 440 variables.