SunzmaryThe reaction of carbon dioxide with dicyclopentadienyldiphenyltitanium leads to carboxylation of the phenyl ring and to metallocycle formation; the molecular structure of the compound has been determined by an X-ray study.Pbcu. The structure was determined by the heavy atom method and refined by least-squares (full-matrix, isotropic temperature factors). A t the present stage of refinement R = 0.13 for GU. 800 independent reflexions. The molecular structure (Figure) is in full agreement with the formulation CARBON DIOXIDE is known to react with transition metal compounds (excluding carbonate formation) either with the formation of complexes112 or with insertion of CO, into the metal-hydrogen bond., 9 4 We have now investigated the reaction of bis-(n-cyclopentadieny1)diphenyltitanium with carbon dioxide (80--90"; CO, bubbled through a solution in xylene) , which gave diamagnetic, air-stable, red crystals, m.p. 192-195" (decomp.), (35%) soluble in acetone and benzene, but insoluble in ether or light petroleum. The i.r. spectrum shows Ph and C5H5 absorptions and also bands a t 880m, 1130s, 1280vs, 1620s, and 1660vs cm-l; lH n.m.r. spectrum: 6 6 . 6 7 . 5 5 (phenyl) and 6-45 (C5H5) p.p.m. (relative areas 4 : 10).Heating of the compound with dilute H2S04 (1 : 1) gives benzoic acid and the action of BF, in methanol (100"; 3 h) gives methylbenzoate (70%). Pyrolysis a t 200" gives CO,, benzene, and cyclopentadiene. These data, together with elemental analyses, its molecular weight, and its mass spectrum support the formulation as structure (I).
J-We carried out an X-ray study to investigate the mode of CO, co-ordination. Crystals of (I) are orthorhombic. Crystal data: u = 13.744(2), b = 14.410(2), c = 13.774(2) A; D, = 1-46, D, = 1.46 g crn4 for 2 = 8, space group
