Fluorocarbene, fluoroolefin, and fluorocarbyne complexes of Rh

The manuscript reports a series of complexes of small perfluorocarbon ligands with the (PNP)Rh fragment, analysis of their electronic structure, and comparison to the hydrocarbon analogues and complexes of CO and NO+.


I. General Considerations
Unless specified otherwise, all manipulations were performed under an argon atmosphere using standard Schlenk line or glove box techniques. Toluene, pentane, and isooctane were dried and deoxygenated (by purging) using a solvent purification system by MBraun and stored over molecular sieves in an Ar-filled glove box. C6D6 and CDCl3 was dried over and distilled from Na/K/Ph2CO/18-crown-6 and stored over molecular sieves in an Ar-filled glove box.
Fluorobenzene and benzotrifluoride were dried with and then distilled from CaH2 and stored over molecular sieves in an Ar-filled glove box. Me3SiCF3 was degassed prior to use and stored in an Ar-filled glove box. CsF was grounded and dried at 130 °C under vacuum for 2 days.
(PNP)Rh(TBE) 1 3 All other chemicals were used as received from commercial vendors unless otherwise specified.

Synthesis of [(PNP)Rh≡CF
The mixture was warmed to room temperature and CsF (10 mg, 0.66 mmol) was added to the J. Young tube and rotated overnight. By morning the solution had turned from dark blue to a brownish green. Analysis by 19 F NMR spectroscopy showed that 98% of the visible signals had been converted back to (PNP)Rh(C2F4) (as judged by integration versus a residual FPh peak).
The solution in the J. Young tube was transferred to a vial and pentane was added to precipitate any cationic species and the solution was filtered through celite to form an orange filtrate. 1 H, 31 P{ 1 H}, and 19 F NMR spectroscopy all confirmed that (PNP)Rh(C2F4) was the resulting product.

X-Ray data collection, solution, and refinement for (PNP)Rh(C2F4).A red block
crystal of suitable size (0.17 x 0.14 x 0.11 mm) was selected from a representative sample of crystals of the same habit using an optical microscope, mounted onto a nylon loop and placed in a cold stream of nitrogen. Low temperature (110 K) X-ray data were obtained on a Bruker APEXII CCD based diffractometer (Mo sealed X-ray tube, Kα = 0.71073 Å). All diffractometer manipulations, including data collection, integration and scaling were carried out using the Bruker APEXII software. 4 An absorption correction was applied using SADABS. 5 The structure was solved in the monoclinic C2/c space group using XS 6 (incorporated in SHELXTL). The S27 solution was refined by full-matrix least squares on F 2 . No additional symmetry was found using ADDSYMM incorporated into the PLATON program. 7 All non-hydrogen atoms were refined with anisotropic thermal parameters. All hydrogen atoms were placed in idealized positions and refined using a riding model. The structure was refined (weighted least squares refinement on F 2 ) and the final least-squares refinement converged to R1 = 0.0293 (I > 2σ(I), 2775 data) and wR2 = 0.0862 (F 2 , 3031 data, 169 parameters).

X-Ray data collection, solution, and refinement for [(PNP)Rh≡CF][CHB11Cl11].
A blue prism (0.20 x 0.17 x 1.00 mm) was selected from a representative sample of crystals of the same habit using an optical microscope, mounted onto a nylon loop and placed in a cold stream of nitrogen (110 K). Low-temperature X-ray data were obtained on a Bruker APEXII CCD based diffractometer (Mo sealed X-ray tube, Kα = 0.71073 Å). All diffractometer manipulations, including data collection, integration and scaling were carried out using the Bruker APEXII software. Error! Bookmark not defined. The space group was determined on the basis of systematic absences and intensity statistics and the structure was solved in the orthorhombic space group Pna21 by direct methods using XS Error! Bookmark not defined. (incorporated in SHELXTL) and refined by full-matrix least-squares on F 2 . No obvious missed symmetry was reported by PLATON. Error! Bookmark not defined. All non-hydrogen atoms were refined with anisotropic thermal parameters.
Hydrogen atoms were placed in idealized positions and refined using riding model. The structure was refined (weighted least squares refinement on F 2 ) and the final least-squares refinement converged to R1 = 0.0590 (I > 2σ(I), 9513 data) and wR2 = 0.1511 (F 2 , 10849 data, 511 parameters).