“…These considerations and other literature precedents − have led us to propose the mechanism in Scheme to rationalize the formation of complexes 5 and 6 . Abstraction of one of the methide ligands of 1 or 2 by H + B - followed by coordination of acetylene gives intermediate i .…”
Section: Resultsmentioning
confidence: 79%
“…A related pathway was proposed in the catalytic reaction of acetylene with (PhCN) 2 PdCl 2 to produce six-membered rings. , Intermediate iv then undergoes β-hydride elimination to produce a free five-membered ring that recoordinates to the ruthenium center, forming intermediate v . Insertion of the resulting diene into the Ru−H bond gives the σ−π allyl intermediate vi , , which converts to the more thermodynamically stable isomer (i.e., 5 or 6 ). 1 …”
The reactions of (η 6 :η 1 -C 6 H 5 CH 2 CH 2 PR 2 )Ru(CH 3 ) 2 , where R ) Cy (1), Ph (2), with boron activators in the presence of CO, acetylene, ethylene, and norbornene were explored. The reaction of 1 and 2 with H( and 4, respectively). The reaction of 1 and 2 with H + Bin the presence of acetylene afforded polyacetylene and [(η 6 -C 6 H 5 -CH 2 CH 2 PR 2 )Ru(η 3 -CH 3 CHC 5 H 5 )][B(3,5-C 6 H 3 (CF 3 ) 2 ) 4 ] (5 and 6, respectively). The latter reactions were proposed to proceed via coordinative insertion of acetylene into Ru-alkyl bonds. In contrast, the reaction of 2 with H + Bin the presence of ethylene initially afforded the precursor complex [(η 6 :η 7). Finally, the reaction of 1 and 2 with H + Bin the presence of excess norbornene afforded ring-opened polynorbornene, presumably via Ru-catalyzed ring-opening metathesis polymerization (ROMP). The reaction products were characterized by IR and NMR spectroscopy. Single-crystal X-ray structural analyses of complexes 3, 5, 6, and 7 were also performed.
“…These considerations and other literature precedents − have led us to propose the mechanism in Scheme to rationalize the formation of complexes 5 and 6 . Abstraction of one of the methide ligands of 1 or 2 by H + B - followed by coordination of acetylene gives intermediate i .…”
Section: Resultsmentioning
confidence: 79%
“…A related pathway was proposed in the catalytic reaction of acetylene with (PhCN) 2 PdCl 2 to produce six-membered rings. , Intermediate iv then undergoes β-hydride elimination to produce a free five-membered ring that recoordinates to the ruthenium center, forming intermediate v . Insertion of the resulting diene into the Ru−H bond gives the σ−π allyl intermediate vi , , which converts to the more thermodynamically stable isomer (i.e., 5 or 6 ). 1 …”
The reactions of (η 6 :η 1 -C 6 H 5 CH 2 CH 2 PR 2 )Ru(CH 3 ) 2 , where R ) Cy (1), Ph (2), with boron activators in the presence of CO, acetylene, ethylene, and norbornene were explored. The reaction of 1 and 2 with H( and 4, respectively). The reaction of 1 and 2 with H + Bin the presence of acetylene afforded polyacetylene and [(η 6 -C 6 H 5 -CH 2 CH 2 PR 2 )Ru(η 3 -CH 3 CHC 5 H 5 )][B(3,5-C 6 H 3 (CF 3 ) 2 ) 4 ] (5 and 6, respectively). The latter reactions were proposed to proceed via coordinative insertion of acetylene into Ru-alkyl bonds. In contrast, the reaction of 2 with H + Bin the presence of ethylene initially afforded the precursor complex [(η 6 :η 7). Finally, the reaction of 1 and 2 with H + Bin the presence of excess norbornene afforded ring-opened polynorbornene, presumably via Ru-catalyzed ring-opening metathesis polymerization (ROMP). The reaction products were characterized by IR and NMR spectroscopy. Single-crystal X-ray structural analyses of complexes 3, 5, 6, and 7 were also performed.
“…We have reported on the nature of bimetallic compounds produced in THF when (1) VC13 is reduced by metallic Zn2 and (2) TiCl3 is reacted with ZnCl2. 3 We have also noted3 that such reactions sometimes produce materials with direct (i.e.…”
h e use of t h e diffractometer. The experimental assistance of J. M. Ball, C. L. Merritt, a n d Dr. S. N a n d a n a a n d Dr. R. Yamdagni's advice a n d help in obtaining spectroscopic data are gratefully acknowledged. We also t h a n k Dr. Scott Collins for helpful discussions.Registry No. meso-1, 97371-16-9; dl-1 (isomer I), 97371-17-0; 2, 81609-97-4; 3, 97295-68-6; [WC13(SMe)], 97295-72-2; [WCI,(SEt)], 97295-74-4; [ WCI,(SPh)], 97295-76-6; Me3Si(SMe), 3908-55-2; Me,Si(SEt), 5573-62-6; Me3Si(SPh), 4551-1 5-9; WCI,, 13283-01-7; WC14(Me2S)2, 53922-82-0; Et,SiH, 617-86-7
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