1427319-84-3Relevant articles and documents
Synthesis of ruthenium half-sandwich complexes by naphthalene replacement in [CpRu(C10H8)]+
Perekalin, Dmitry S.,Karslyan, Eduard E.,Trifonova, Evgeniya A.,Konovalov, Andrew I.,Loskutova, Natalia L.,Nelyubina, Yulia V.,Kudinov, Alexander R.
, p. 481 - 493 (2013/04/10)
Replacement of the naphthalene ligand in ruthenium complex [CpRu(C 10H8)]+ (1) by halide anions readily proceeds at room temperature to give insoluble oligomeric species [CpRuX]n (X = Cl, Br, I). Similar reactions in the presence of mono- or bidentate ligands afford complexes [CpRuL2X] where L = CO, P(OMe)3, tBuNC; L2 = dppm, dppe, dppp, bipy, phen, cod, nbd, or 1,4- diphenylbutadiene. Useful catalysts [CpRu(cod)X] were obtained by this method in 70-90 % yields. The structure of [CpRu(cod)I] was determined by X-ray diffraction. Reaction of 1 with Br- and allyl bromide afforded RuIV complex [CpRu(η3-C3H 5)]Br2. Cation 1 also was found to react with azide anion in the presence of bidentate phosphanes to afford [CpRuL2N 3] (L2 = dppm, dppe). Reaction of 1 with neutral ligands in the absence of nucleophilic anions proceeded under visible-light irradiation to give cationic complexes [CpRuL3]+ [L = CO, P(OMe) 3, P(OEt)3, tBuNC] in 80-90 % yields. Complex 1 (2 mol-%) catalyzed cyclotrimerization of dipropargyl Meldrum's acid with various alkynes RC≡CH [R = H, Bu, Hex, Ph, SiMe3, (CH2) 4C≡CH, (CH2)3OH, (CH2) 2Br, CH2OMe, CH2OAc, CH2NMeBoc] producing benzene derivatives in 50-85 % yields. According to DFT calculations, the attack of the first ligand (Cl- or L) is a rate-determining step in the naphthalene replacement in 1. The activation barrier for attack of the Cl- anion is ca. 10 kcal mol-1 lower in energy than that of the neutral ligands L = CO, MeNC, MeCN, thus providing a rationale for the faster reaction in the presence of halide anions. The barriers for naphthalene replacement in 1 were also found to be ca. 10-15 kcal mol-1 lower in energy than those for the benzene replacement in [CpRu(C6H 6)]+. The readily available (naphthalene)ruthenium complex 1 was shown to be a convenient precursor for various [CpRuL2X] complexes and an efficient catalyst for the cyclotrimerization of 1,6-diynes with assorted alkynes. Copyright
