339322-97-3Relevant academic research and scientific papers
Incorporation of alkyne and vinylidene ligands into tetrazolate groups at a sulfur-rich dimolybdenum site using sodium azide
Schollhammer, Philippe,Cabon, Nolwenn,Kervella, Anne-Cécile,Pétillon, Fran?ois Y.,Rumin, René,Talarmin, Jean,Muir, Kenneth W.
, p. 495 - 502 (2008/10/08)
Treatment of either the μ-alkyne complex [Mo2Cp 2(μ-SMe)3(μ-PhCCH)](BF4) (1) or the μ-vinylidene derivatives [Mo2Cp2(μ-SMe) 3(μ-η1:η2-(CCHR)](BF4) (2) (R=Ph, Tol, nPr, C(CH3)=CH2) with NaN3 in ethanol at room temperature readily afforded μ-tetrazolate carbene complexes [Mo2Cp2(μ-SMe)3){μ-η 1(C):η1(N)-N4CCR)}] (R=Ph (4a), Tol (4b), nPr (4c), C(CH3)=CH2 (4d)). A mechanism which accounts for the formation of 4 by intramolecular 1,3-dipolar cycloaddition of metal-coordinated azide ligands to metal-coordinated nitriles is discussed. The structure of complex 4a has been determined by single X-ray diffraction analysis.
Activation of terminal alkynes at the sulfur-rich bimetallic site [MoIII2Cp2(μ-SMe)3]+: Alkyne-vinylidene conversion and C-S and C-C couplings promoted by addition of unsaturated substrates (RC≡CH, RN≡C, S=C=S).
Schollhammer, Philippe,Cabon, Nolwenn,Capon, Jean-Fran?ois,Pétillon, Fran?ois Y.,Talarmin, Jean,Muir, Kenneth W.
, p. 1230 - 1242 (2008/10/08)
Reactions of the bis(nitrile) compound [Mo2Cp2 (MeCN)2(μ-SMe)3](BF4) (1) with terminal alkynes in a 1:1 ratio in dichloromethane at room temperature led to the alkyne adduct [Mo2Cp2(μ-SMe)3(RCCH)] (BF4) (2: R = Tol (2a), Ph (2b), CH3C=CH2 (2c), nPr (2d), CO2Me (2e), CF3 (2f)). Compounds 2a-d were readily deprotonated with Et3N to give neutral acetylide derivatives [Mo2Cp2(μ-η1:η2- C≡CR)(μ-SMe)3] (3). Protonation of 3 afforded exclusively the vinylidene complexes [Mo2Cp2(μ-η1: η2-C=CHR) (μ-SMe)3](BF3) (4). Reaction of 1 with an excess of terminal alkyne RCCH in dichloromethane gave either the six-membered metallacycle compounds [Mo2Cp2(μ- η2:η4-CR=CHCR=CHSMe)(μ-SMe)2] (BF4) (5) or the S-methylthiophenium derivatives [Mo2Cp2(μ-η2:η4- C4H2R2SMe)(μ-SMe)2] (BF4) (6), depending on the nature of the R groups. Further reactions of the alkyne adducts 2 with isocyanide and carbon disulfide led to the vinyl-thioether complexes [Mo2Cp2(μ- η1:η3-CR=CR′-SMe)-(μSMe)2 (RNC)](BF4) (7, 8) and to their CS2 adducts [Mo2Cp2(S2C-CR′=CRSMe)(μ- SMe)2]-(BF4) (9, 10), which arise from regioselective C-S coupling. A mechanism is proposed for the formation of the cyclic thiometalla compounds 5, 9, and 10 and of the thiophenium species 6 which assigns a key intermediate role to vinyl-thioether species. The molecular structures of 3a, 4b, and 7a have been established by X-ray diffraction studies.
