Solid state structure and fluxionality in solution of [H4Ru4(CO)11L] (L=P(C6F5)3, PMe2Ph, P(OMe)3 and P(OEt)3): two different structures

Synthesis, characterization and reactivity of tetranuclear ruthenium hydrido clusters containing chiral phosphineligands

“…from linearity [159.84(2) • ] than the analogous angles in the three aforementioned species and is strictly comparable to the value found in [H 4 Ru 4 (CO) 11 (PMe 2 Ph)]21 …”

A novel heterobidentate chiral phosphine and its coordination chemistry in transition metal clusters

“…Analysis of the difference Fourier map obtained for (5) indicates that the hydrides adopt the (A) structural pattern in the crystal cell of this complex. Completely in line with the general trend observed in the H 4 Ru 4 (CO) 12 -substituted derivatives [56][57][58], the Ru-Ru edges spanned by the hydride ligands are the longest in the tetrahedron (see Table 2). This is also consistent with the structure of the ''H 4 Ru 4 P'' fragment corresponding to (A) isomer.…”

“…In the same temperature range, the proton spectrum is complicated because of the dynamics of the hydrides, which are not static, even at 176 K. These observations can be explained by the exchange between the two isomeric forms of the hydride environment, for example between the (A) and (B) isomers shown above. This would be analogous to the dynamics found in the H 4 Ru 4 -(CO) 11 (PR 3 ) clusters, suggested earlier [57,59]. Under the framework of this hypothesis, the proton spectrum of the system at 223 K is a weighted average of the spectra of the exchange components.…”

“…Similar to the other H 4 Ru 4 (CO) 11 (PR 3 ) derivatives studied by solution NMR spectroscopy [57,59], the hydride environment of (5) is fluxional at room temperature giving rise to a singlet at À17.29 ppm, which corresponds to fast exchange of all the hydrides at this temperature. The 1 H VT spectra of (5) are shown in Fig.…”

“…The isomer (A) was found in solid state structure of H 4 Ru 4 (CO) 11 (P(OMe) 3 ) [57], H 4 Ru 4 (CO) 11 (P(C 6 F 5 ) 3 ) [57] and H 4 Ru 4 (CO) 11 (PPh 3 ) [58] whereas the H 4 Ru 4 (CO) 11 -(PPhMe 2 ) cluster [57] exists in form (B). Analysis of the difference Fourier map obtained for (5) indicates that the hydrides adopt the (A) structural pattern in the crystal cell of this complex.…”