Jan M. Troup

Conformations of fused cycloalkanes in organometallic compounds : III. The crystal and molecular structures of tricyclo [6.2.0.02,7] deca-3,5-dienetricarbonyliron, (C10H12)Fe(CO)3☆

The structure of tricyclo [6.2.0.02,7] deca-3,5-dienetricarbonyliron, (C10H12)Fe(CO)3, has been determined from X-ray counter data. The space group is P212121 with cell dimension a 11.785(3), b 16.987(7), c 6.032(2) » and with four molecules in the cell. The 1359 reflections, in the range 0° < 20 (Mo-Kα) ⩽ 45°, with intensities significantly above background were included in the refinement which converged to R1 = 0.033 and R2 = 0.029. The molecular structure consist of an Fe(CO)3 moiety bonded to the diene portion of a cyclohexadiene ring. This six-membered ring is fused to a second four-membered ring. Both four-membered rings are essentially planar.

Characterization of a minor product of the reaction of diiron nonacarbonyl with cis-bicyclo[6.2.0]Deca-2,4,6-triene: trans-DI-μ-bis(2,3,4,5,6-pentahapto-tricyclo[6.2.0.02,6] deca-2,4dien-6-yl)dicarbonyldiiron(FeFe)

Abstract The identity of a minor product obtained from the reaction of diiron nonacarbonyl with cis-bicyclo[6.2.0]deca-2,4,6-triene has been ascertained by X-ray crystallography. The product, with the formula [(C10H11)Fe(CO)2]2, is a substituted [(h5-C5H5)Fe(CO)2]2 molecule in which the h5-C5H5 groups are replaced by penta hapto-tricyclo[6.2.0.O2,6]deca-2,4-dien-6-yl groups. The mechanism by which the C10H11 tricyclic system is formed from the initial bicyclo triolefin is obscure although (C10H11)FeH(CO)2 is a probable intermediate. The compound crystallizes in the monoclinic system, space group P21n with a = 9.231(4), b = 9.138(5), c = 12.140(6)A, β = 106.16(4)°, and Z = 2. The intensities of 928 independent reflections (2θmax = 45°) with I > 3 σ(I), collected on a computer-controlled diffractometer with Mo-Ka radiation were used to solve and refine the structure to R1 = 0.051 and R2 = 0.063.

Crystal structure of vanadyl phthalocyanine, phase II

The crystal structure of the title compound has been determined from three-dimensional X-ray diffractometer data. Crystals are triclinic, space group P, with Z= 2 in a unit cell of dimensions a= 12.027(6), b= 12.571(8), c= 8.690(5)A, α= 96.04(5), β= 94.80(5), and γ= 68.20(5)°. The structure was solved by direct and Fourier methods and refined by least-squares techniques to R(on F)= 0.062 for 3 042 independent reflections having Fo2 > 3σ(Fo2). The compound [VO(pc)] is molecular with point-group symmetry C1 and is non-planar with all pc atoms below the isoindole nitrogen-atom plane. Vanadium has a five-co-ordinate square-pyramidal geometry and is 0.575(1)A above the plane. The V–O distance is 1.580(3)A; the mean V–N distance is 2.026(7)A. The compound is composed of sheets of approximately parallel and overlapping [VO(pc)] molecules. Intermolecular contacts occur with three nearest neighbours. The closest intermolecular approach is 3.208 A(N ⋯ N) while the shortest centroid–centroid distance is 5.378 A. Dimers are absent.

The structure of a tricarbonyliron derivative of Barbaralone

One minor product of the reaction of Fe 2 (CO) 9 in ether with impure bicyclo[2.6.0]deca-2,4,6-triene, in which the major impurity was cyclooctatetreane, is a derivative of barbaralone, tricyclo [3.3.1.0 2,8 ]nona-3,6-diene-9-one, I, in which the three membered ring has been opened at the 2.8 bond. The systematic name for the compounds is (2,3,4,8-η 4 -bicyclo[3.2.2]-nona-3,6-diene-2,8-yl-9-one)tricarbonyliron. It is identical to the product which can be obtained by direct reaction of barbaralone with Fe 2 (CO) 9 in ether. The most likely progenitor of the barbaralone moiety in the present instance in the C 8 H 8 impurity, although there is no direct proof of this. Compound I crystallized from pentane at −5° in the triclinic system with unit cell dimensions a 7.476(2), b 11.912(4), c 6.606(2) A, α 94.55(2)°, β 110.17(2)°, γ 92.38(3)°, V 549.0(3) A 3 and Z 2. Space group P . The structure was solved by Patterson and Fourier methods and refined to R 1 0.021 and R 2 0.031 with all nonhydrogen atoms treated anisotropically and the eight hydrogen atoms treated isotropically, using 1283 reflections having F 2 0 > 3 σ ( F 2 0 ). The coordination about the iron atom can be described as distorted octahedral if the η 3 -allyl is considered to occupy two of the six positions. The three CO ligands are mutually cis . The allyl group is trans to two of them and FeC σ bond is trans to the third. The mean FeCO bond lengths is 1.795(5) A, the FeC(allyl) distances are 2.137(3), 2.069(2) and 2.195(3) A, and the FeC σ bond has a length of 2.110(2) A. The broad geometrical features of the structure are quite at variance with the concept of a “homobutadiene complex”.

The molecular structure of a product of the reaction of bicyclo[6.2.0]deca-2,4,6-triene with diiron nonacarbonyl ☆

Abstract The reaction of bicyclo[6.2.0]deca-2,4,6-triene with diiron nonacarbonyl affords at least four products, one of which is a yellow substance with the empirical formula C10H12Fe2(CO)6. The structure of this substance has been determined by X-ray crystallography. The organic portion consists of a 1,3-cyclohexadiene ring with a CH2 group at the 5 position and an allyl group at the 6 position. One Fe(CO)3 group is bound to the 1,3-diene part of the organic group and another Fe(CO)3 group is bound to the CH2 group by a CFe σ bond and to the allyl group functioning as a trihapto allyl ligand. The essential crystallographic data are as follows: The space group is P 1 with a a = 7.140(3), b = 10.029(6), c = 13.875(5) Ǎ, α = 110.09(4)°, β = 118.50 (3)°, γ = 77.65(4)°, V = 818.5(7)Ǎ3 and Z = 2. The structure was solved by Patterson heavy atom methods. With all atoms located the conventional R value for 1210 observed reflections measured with a Syntex P 1 diffractometer is 0.044.

The crystal and molecular structure of the bis(tricarbonyliron) derivative of 3,3′-bis(bicyclo[4.2.0] octa-2,4-diene)

Abstract The reaction of bicyclo [2.6.0] deca-2,4,6-triene containing about 5% impurities, mostly cyclooctatetraene, with diiron nonacarbonyl in ether at 22° gave a minor product, 3,3′-bis(bicyclo [4.2.0] octa-2,4-dienetricarbonyliron), [(C 8 H 9 )- Fe(CO) 3 ] 2 , which is composed of two linked units of the previously reported compound. The origin of this new substance is at present unknown. Data were collected using the θ/2θ scan technique and a total of 1788 reflections were measured. The structure was solved by Patterson and Fourier methods. Non-hydrogen atoms were refined anisotropically and hydrogen atoms isotropically to give agreement factors of R 1 = 0.030, and R 2 = 0.039. The space group is P 1 with cell dimensions of a 8.178(2), b 6.800(3), c 9.729(3)», α 101.98(3)°, β 106.99(2)°, γ 95.83(3)°, and V 498.5(3)» 3 with Z = 1. The structure consists of two bicyclo[4.2.0]octa-2,4-dienetricarbonyliron moieties related by an inversion center. The molecule shows some distortion in the usual hexa-1,3-dienetricarbonyliron bond distances and angles. This distortion is probably due to the carboncarbon bond between the two halves of the molecule at the second carbon in the 1,3-diene group.

Accurate determination of a classic structure in the metal carbonyl field: nonacarbonyldi-iron

An equidimensional single crystal of Fe2(CO)9 has been used to reinvestigate the molecular structure. The results confirm all the main qualitative features originally reported by Powell and Ewens, and provide the level of accuracy needed for comparison with other structures and for molecular orbital calculations. The molecular symmetry is C3h(), but there is little deviation from the higher symmetry D3h(m2). The important molecular dimensions, with their estimated standard deviations in parentheses are: Fe–Fe, 2·523(1)A; Fe–C (terminal), 1·838(3)A, Fe–C (bridge), 2·016(3)A; C–O (terminal), 1·156(4)A; C–O (bridge), 1·176(5)A; C(term.)–Fe–C(term.), 96·1 (1)°; Fe–C(bridge)–Fe, 77·6(1)°; Fe–C–O (term.), 177·1 (3)°. Space group: P63/m. a= 6·436(1)A, c= 16·123(2)A, V= 578·4(2)A3, Z= 1. Of 1064 unique reflections measured with a counter diffractometer, 604 with intensity at least three times the e.s.d. were used to refine the structure (34 parameters) to final discrepancy indices of 0·040 (unit weighted data) and 0·050 (weighted data).

The structure of 3,4,5,6-tetrahaptocyclodeca-1,3,5,7-tetraene-tricarbonyliron, a PI complex of a ten-membered, monocyclic polyolefin

Abstract The title compound, a minor product of the reaction of Fe 2 (CO) 9 with bicyclo[6.2.0]deca-2,4,6-triene, crystallizes in space group P 1 with a = 10.401(2) A, b = 9.779(2) A, c = 6.554(2) A; α = 98.69(2)°; β = 111.76(2)°; γ = 82.65(2)°; V = 610.1(2) A 3 ; Z = 2. The structure has been refined to R 1 = 0.029 and R 2 = 0.036. No crystallographic symmetry is imposed on the molecule but it has an approximate mirror plane of symmetry. The C 10 H 12 ligand is present as a coordinated 1,3,5,7-cyclodecatetraene, coordinated to the Fe(CO) 3 group through the cis , cis -3,5-diene unit. The bond distances and angles within the local (butadiene)Fe(CO) 3 moiety are normal, with one CO group lying over the open side of the butadiene chain. The central C—C distance is 0.028(9) A shorter than the mean of the two outer C—C distances of the butadiene chain. The C 10 ring lies in four planes with dihedral angles between adjacent planes (starting with the plane of the coordinated butadiene unit) of 41.5°, 50.6° and 53.8°.