Metallooxacyclobutane complexes, Pt[C2(CN)4O]L2 (L = P(C6H5)3, P(p-CH3C6H4)3, As(C6H5)3), were prepared from the reaction between tetracyanooxirane (2,2,3,3-tetracyanooxacyclopropane, C2(CN)4O) and PtL4. The crystal and molecular structure of the complex where L = As(C6H5)3 has been determined from three-dimensional X-ray diffraction data. The crystal has symmetry consistent with the space group P21/c [C2λ5] with four molecules of the complex in a unit cell of dimensions a = 9.933 (2) Å, b = 20.477 (3) Å, c = 18.634 (3) Å, and β = 95.42 (1)°. The structure was refined by least-squares techniques to a conventional R index of 0.039 based on 4819 reflections above background collected using a four-circle diffractometer. The structure determination shows that Pt[As(C6H5)3]2 has inserted into the carbon-oxygen bond of the oxirane. Such a metallooxacyclobutane ring has recently been suggested as an intermediate in the catalytic formation of ethylene carbonate from Ni° complexes, ethylene oxide, and CO2. Comparisons are made between the structural parameters of the present complex, the closely related metallocyclobutane complex Pt[C2(CN)4CH2][P(C6H5)3]2, and the small rings tetracyanooxirane and 1,1,2,2-tetracyanocyclopropane. Spectroscopic data and chemical behavior of the metallooxacyclobutane complexes are reported.
ASJC Scopus subject areas
- Colloid and Surface Chemistry