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Structure Of Trans-chloronitrosyltetrakis(pyridine)ruthenium(II) Bis(hexafluorophosphate) Hemihydrate
Published 1983 · Chemistry
Abstract The structure of trans-chloronitrosyltetrakis(pyridine)ruthenium(II) bis(hexafluorophosphate) hemihydrate, [RuClpy4NO] (PF6)2·1/2H2O, was determined by X-ray structure analysis. The compound crystallizes in monoclinic form, space group P21/c, with a = 16.0201(12), b = 1.5306(15), c = 27.0912(20) A, β = 91.78(1)°, Z = 8. Least-squares refinement of the structure yielded a final R factor of 0.051 for 4229 independent reflections with |Fo|⩾ 3σ(|Fo|) collected byu a counter method. There are two crystallographically independent formula units in the asymmetric unit. Both have essentially the same structure. The complex cation has a trans octahedral geometry with a nitrosyl and a chloride in the axial position and four pyridines in the equatorial position. The four pyridines form a propeller-like arrangement with an average pitch of about 46°. The RuNO group is approximately linear: the RuNO angle is 174.8(1.9)°, the RuN bond length is 1.760(9) and that of N is 1.132(13) A. The RuCl bond length is 2.314(1) A; this is shortened by the trans-shortening effect of the nitrosyl. The average separation distance of Ru(pyridine) is 2.111(6) A. NMR spectra, along with their temperature dependence, suggests that rapid cogwheel rotation of pyridine rings about RuN(py) axis is occuring in solution.