Diverse C−C Bond-Forming Reactions of Bis(carbene)platinum(II) Complexes
Abstract
The platinum(0) complex Pt(PPh_3)_4 catalyzes coupling of the carbene ligands of (CO)_5Cr{C(OMe)(p-MeOC_6H_4)} (1). The stable bis(carbene)platinum(II) complexes Cl_2Pt{C(OMe)(Me)}_2 (3), Br_2Pt{C(OMe)(Me)}_2 (4), and Cl_2Pt{C(O^iPr)(Me)}_2 (5) can be induced to undergo C–C coupling reactions by several means. Reduction of 3–5 to platinum(0) with cobaltocene results in formation of internal olefins, (E/Z)-2,3-dimethoxybut-2-ene (6) or (E/Z)-2,3-diisopropoxybut-2-ene (7). Reaction of 3–5 with PPh3 yields terminal olefins, 2,3-dimethoxybut-1-ene (13) or 2,3-diisopropoxybut-1-ene (15), along with Cl_2Pt(PPh_3)_2 (12) or Br_2Pt(PPh_3)_2 (14). In contrast, addition of pyridine to 3–5 does not effect C–C coupling; instead, the acyl complexes cis-Cl(py)Pt(COMe){C(OMe)(Me)} (8), cis-Br(py)Pt(COMe){C(OMe)(Me)} (9), and cis-Cl(py)Pt(COMe){C(O^iPr)(Me)} (10) are obtained, with concomitant formation of alkyl halide. Possible mechanistic pathways for C–C bond formation are discussed, as well as explanations for the different reactivities observed for pyridine and PPh_3.
Additional Information
© 2012 American Chemical Society. Received: August 1, 2012. Publication Date (Web): August 31, 2012. This work was generously funded by BP through the Methane Conversion Cooperative (MC2) program. An NSF-GRF to R.C.K. is gratefully acknowledged. We thank Dr. David VanderVelde for assistance with NMR experiments. R.C.K. is grateful to Prof. Alexander J. M. Miller and Prof. Theodor Agapie for useful discussions. The authors declare no competing financial interest.Attached Files
Published - om300733h.pdf
Supplemental Material - om300733h_si_001.pdf
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Additional details
- Eprint ID
- 35457
- Resolver ID
- CaltechAUTHORS:20121114-105428991
- BP MC2 program
- NSF Graduate Research Fellowship
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2012-11-14Created from EPrint's datestamp field
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2021-11-09Created from EPrint's last_modified field