SOLUTION STRUCTURES AND DYNAMICS OF RU-4(MU-H)(4)(CO)(12-X)L(X) (X=1-4, L=P(OET)(3), PPH(3) X=1, 2, L=ASPH(3)) DERIVATIVES BY VT MULTINUCLEAR NMR-SPECTROSCOPY - X-RAY STRUCTURE DETERMINATION OF RU-4(MU-H)(4)(CO)(10)(P(OET)(3))(2)