Synthesis of Ruthenium Half‐Sandwich Complexes by Naphthalene Replacement in [CpRu(C10H8)]+12. Issue 4 (4th December 2012)

• Record Type: Journal Article
• Authors: Perekalin, Dmitry S.; Karslyan, Eduard E.; Trifonova, Evgeniya A.; Konovalov, Andrew I.; Loskutova, Natalia L.; Nelyubina, Yulia V.; Kudinov, Alexander R.
• Is Part Of: European journal of inorganic chemistry. Issue 4(2013)
• Page Start: 481
• Page End: 493
• Publication Date: 2012-12-04
• Subjects: Ruthenium -- Naphthalene -- Cyclopentadienyl ligands -- Diene ligands -- Density functional calculations; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201201112
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: Replacement of the naphthalene ligand in ruthenium complex [CpRu(C10 H8 )] + (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 [CpRuL2 X] where L = CO, P(OMe)3, t BuNC; 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 of1 with Br – and allyl bromide afforded Ru IV complex [CpRu(η 3 ‐C3 H5 )]Br2 . Cation1 also was found to react with azide anion in the presence of bidentate phosphanes to afford [CpRuL2 N3 ] (L2 = dppm, dppe). Reaction of1 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, t BuNC] in 80–90 % yields. Complex1 (2 mol‐%) catalyzed cyclotrimerization of dipropargyl Meldrum's acid with various alkynes RC≡CH [R = H, Bu, Hex, Ph, SiMe3, (CH2 )4 C≡CH, (CH2 )3 OH, (CH2 )2 Br, CH2 OMe, CH2 OAc, CH2 NMeBoc] 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 in1 . 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 in1 were also found to be ca. 10–15 kcal mol –1 lower in energy than those for the benzene replacement in [CpRu(C6 H6 )] + . Abstract : The readily available (naphthalene)ruthenium complex1 was shown to be a convenient precursor for various [CpRuL2 X] complexes and an efficient catalyst for the cyclotrimerization of 1, 6‐diynes with assorted alkynes.