Die Koordinationschemie C=S-funktioneller Verbindungen. X. Kationische Ruthenium - Thiobenzaldehyd-Komplexe: Synthese durch Hydridabstraktion aus Benzylthiolat-Komplexen, Struktur, dynamisches Verhalten und Reaktionen

Article abstract of DOI:10.1016/0022-328X(94)80212-2

Hydride abstraction from using triphenylcarbenium hexafluorophosphate yields ionic thiobenzaldehyde complexes PF6.With bulky ligands R3P only η¹(S) isomers are formed, whereas a dynamic η¹/η² equilibrium is observed for (R3P)2 = (Me3P)2, dmpe.An X-ray structure determination was carried out on PF6*0.5 Et2O (triclinic, space group P<*>, a = 11.372(4) Angstroem, b = 12.782(5) Angstroem, c = 14.548(4) Angstroem, α = 70.33(1) deg, β = 80.61(2) deg, γ = 81.91(2) deg, Z = 2): Ru-P1: 2.296(1) Angstroem, Ru-P2: 2.301(1) Angstroem, Ru-S: 2.314(1) Angstroem, S-C6: 1.632(5) Angstroem.Control experiments show that the β-hydride abstraction is initiated by single electron oxidation of the thiolate complex to give a radical cation intermediate.A fairly large kinetic isotope effect (KIE) of the H-transfer step (k_H/k_D = 5.6 using ⁺ and 7.4 using ⁺ as oxidant) demonstrates that the ruthenium is not involved.The thiobenzaldehyde complexes readily add nucleophilessuch as H^-, D^-, PMe3, OR^-, SR^-, and carbanions.With (R3P)2 = dpme moderate diastereoselectivities are found in some of these reactions. <4+2>-Cycloadditions have been carried out with 2,3-dimethylbutadiene and cyclopentadiene.The latter are moderately diastereoselective for (R3P)2 = dpme and highly exo-selective for (R3P)2 = dppm.An X-ray structure determination of PF6*MeCN (monoclinic, space group P2₁/c, a = 13.463(6) Angstroem, b = 16.071(3) Angstroem, c = 20.813(9) Angstroem, β = 92.30(2) deg, Z = 4) reveals that the E configuration of the C=S bond is retained in the Diels-Alder adduct. Key words: Ruthenium; Thiobenzaldehyde; Structure; Addition