Synthesis and characterization of high-valent oxo olefin and oxo carbonyl complexes. Crystal and molecular structure of W(O)Cl2(CH2:CH2)(PMePh2)2

Abstract

Argon matrix, 12 K. 6 Absolute value of the angle between the IR transition moment and the * polarization direction. "Assigned as the C=C stretch. Calculated frequency, 1546 cm"1 (MNDO X 0.915), calculated </>c=c = 90°. unreacted 3 and, particularly at the higher temperatures, a stable product to which we assign the structure 4.7 The evidence for structure 1 is (i) a 1557-cm"1 band in the C=C stretching region, relatively weak in the IR (Figure 1), but the strongest of all the Raman bands. The shift relative to 5 (1685 cm"1) is compatible with strong double pyramidalization of 1. (ii) A broad UV band peaking at 245 ± 15 nm, compatible with the expected lowering of the * excitation energy. Irradiation at 248 nm bleaches both the UV and the IR bands associated with 1 and increases the IR peaks of 4; no additional products are detected, (iii) Above ~165 K in the neat sample, which is quite rigid, and already above ~40 K in the much less viscous argon-matrix-isolated sample, the IR bands of 1 gradually disappear and those of the known5 2 + 2 dimer of 1 grow; a GC comparison with an authentic sample (SE-30 column) confirms that the dimer is the chief product formed on warm-up.Synthesis and Characterization of High-Valent Oxo-Olefin and Oxo-Carbonyl Complexes. Crystal and Molecular Structure of W(0)Cl2(CH2=CH2)(PMePh2)2

A Diphenylcyclopropene Complex of Tungsten, [WCl2O(PMePh2)2(η2-3,3-diphenylcyclopropene)], Precursor to a Tungsten–Oxo–Olefin Metathesis Catalyst

“…The phosphine ligands are trans with respect to one another and the pBWmp angle [154.99(7) °] suggests there is significant steric crowding between the phosphine and olefin ligands. This steric effect is also observed in [W(PMePh2)2C120(r/2-ethylene)] (Su, Cooper, Geib, Rheingold & Mayer, 1986). The ProW bond distances are nearly identical; P1--W 2.590(2) and P2--W 2.598(2)A.…”

Concurrent Stabilization of π‐Donor and π‐Acceptor Ligands in Aromatized and Dearomatized Pincer [(PNN)Re(CO)(O)2] Complexes

“…These complexes are important for the green conversion of CO 2 into CO and the oxidation of CO by metal oxides. Mono‐oxo carbonyl complexes of W IV and Mo IV reported by Mayer et al 1d,f,h,i. and Young et al 1a–c,e.…”

Synthesis and characterization of novel (cyclopentadienyl) nitroruthenium complexes

“…[Ru(Cp)(NO)(PPh3)2](PF6)2 (6) 1860 [Ru(Cp)(dppe)(NO)](PF6)2 (7) 1870 [Ru(Cp)(dppm)(NO)](PF6)2 (8)• 1870 [Ru(Cp)(dmpe)(NO)](PF6)2 (9) 1870 "Three closely spaced absorbances occur in the region 1850-1900 cm"1; the peak with the highest absorbance is reported. law approximation.…”