Further studies on the taumerization of the hydrido (alkynyl) cluster Ru3Pt(?-H) {?4-?2-C ? C1Bu} (CO)9(L2) to the vinylidene cluster Ru3Pt{?4-?2-C ? C(H)tBu} (CO)9(L2): X-ray structures of Ru3Pt(?-H){?4-?2-C = C(H)tBu} (CO)9(L2); L2 = dppet, dppp, andS,S-dppb

Abstract

The first order rate constants for the tautomerization of the hydrio(alkynyl) clusters Ru3Pt(μ-H){μ4-ν2-C ≡ C1Bu}(CO)9(L2);1a: L2 = dppe,1b; L2 = dppet,1c; L2 = dppp and1d; L2 =S,S-dppb to the corresponding vinylidene clusters Ru3Pt{μ4-ν2-C = C(H)tBu}(CO)9(L2)2 have been measured, and they follow the orser1d <1a <1b ∼1c. The reactions involving1a and1d exhibit an inverse kinetic deuterium isotope effect. The structures of1b, 2b, 2c, and2d were determined by X-ray crystallography, and are compared with those of1a and2a which have been previously reported. Crystal data for1b, space groupPbca,a = 13.338(4) A,b = 17.771(6) A,c = 36.092(8) A,Z = 8,R(Rw) = 0.059(0.058) for 2342 absorption corrected, observed data; for2b, space group P21/n,a = 10.566(2) A,b = 20.234(5) A,c = 20.270(3) A,β = 96.11(1)°,Z = 4,R(Rw) = 0.043(0.053) for 5865 absorption corrected, observed data; for2c, space group P21/n,a = 14.211(5) A,b = 19.534(2) A,c = 15.870(2) A,β = 100.81(2)°,Z = 4,R(Rw) = 0.055(0.031) for 6566 absorption corrected, observed data: for2d, space group P212121,a = 12.309(4) A,b = 19.047(6) A,c = 19.206(4) A,Z = 4,R(Rw) = 0.055(0.053) fpr 2151 absorption corrected, observed data. The fluxional behavior of1d and1e (which consists of two interconverting isomers) has been examined by variable temperature13C NMR spectroscopy and by31P EXSY.