Polly Sommerville

The crystal and molecular structures of the compounds [(η5-C5H5)Fe(CO)2]2(CH2)n, where 0 n = 3 and 4

Abstract The crystal stuctures of [(η 5 -C 5 H 5 )Fe(CO) 2 ] 2 (CH 2 ) n , n = 3 and 4, have been determined. [(η 5 -C 5 H 5 )Fe(CO) 2 ] 2 (CH 2 ) 3 : a = 21.20, b = 10.39, c = 7.88A, β = 101.6°, U = 1699A 3 , C2/c, Z = 4, R = 0.059, 1036 observed data. [(η 5 -C 5 H 5 )Fe(CO) 2 ] 2 (CH 2 ) 4 : a = 7.63, b = 10.54, c = 21.87A, β = 96.4°, U = 1748A 3 , P2 1 /c, Z = 4, R = 0.051, 1418 observed data. In each compound the iron atoms are joined by simple chains of sigma bonded CH 2 groups. Bond lengths are similar in both: mean Fe-CO 1.75, C-O 1.15, Fe C(cp) 2.11, Fe CH 2 2.08, (cp)C C(cp) 1.41, CH 2 CH 2 1.55A. The (CH 2 ) 3 compound retains a 2-fold axis of symmetry in the crystal. The (CH 2 ) 4 compound has no imposed symmetry, but closely approximates centrosymmetry. The effects of molecular symmetry on the IR spectrum between 2100 and 1900 cm -1 are discussed. The 13 C and 1 H (270 MHz) NMR spectra in solution are shown to be consistent with the structures found crystallographically.

[{Rh(CO)(MeO)2PNEtP(OMe)2Cl}2]: A molecule with a symmetrical formula and an asymmetric structure

Abstract [{Rh(CO)(MeO) 2 PNEtP(OMe) 2 Cl)} 2 ], synthesised by reaction of [{Rh(CO) 2 Cl)} 2 ] with (MeO) 2 PNEtP(OMe) 2 , has an unusual asymmetric structure in which one carbonyl group adopts a terminal position while the other is bridging; the two chlorines are both terminal.

[Rh2(CO)3{(PhO)2PN(Et)P(OPh)2}2]: A substituted derivative of hypothetical [Rh2(CO)7]

Abstract X-ray diffraction shows that [Rh 2 (CO) 3 {(PhO) 2 PN(Et)P(OPh) 2 } 2 ], synthesised by reduction of [{RhCl(CO)(PhO) 2 PN(Et)P(OPh) 2 } 2 ] with amalgamated zinc in the presence of carbon monoxide, has an unusual structure with one rhodium atom square planar and the other trigonal bipyramidal.

A non-closed tetranuclear metal cluster derivative of rhodium and iron: synthesis and molecular structure

The structure of one isomer of [Rh 3 Fe{P(C 6 H 5 ) 2 } 3 (CO) 8 ], synthesised by treatment of [ {Rh(CO) 2 Cl} 2 ] with [Fe(CO) 4 {P(C 6 H 5 ) 2 H} ] in the presence of a base, has been determined by single crystal X-ray diffration. This species rearranges in solution to a second isomer whose structure has been elucidated by 31 P NMR spectral measurements. The reactions of these compounds with carbon monoxide are described.

Crystal and molecular structure of primary nickel dithizonate

The structure of primary nickel dithizonate Ni(Hdz)2 was determined from three-dimensional single-crystal X-ray data, collected by standard film techniques, and refined by the least-squares method to R= 0·12 for 2580 observed and unobserved reflections. The crystals are triclinic, space group P with a= 4·62, b= 10·99, c= 12·50 ± 0·02 A, α= 88·8, β= 97·4, γ= 99·1 ± 0·1°, and Z= 1. The molecule is centrosymmetric with the nickel atom in a square-planar environment bonded to each dithizone ligand through one nitrogen and one sulphur atom to give a five-membered chelate ring with Ni–S 2·19 and Ni–N 1·87 A. The unique non-phenyl hydrogen atom was located.

Remarkable solvent dependent cyclisation of methyl vinyl ketone across the 8,8a and 3,8a positions of Δ1,8a-2-octalone dienamines. First syntheses of the tricyclo[8.4.0.01,6]tetradecane and tricyclo[6.2.2.01,6]dodecane ring systems. Crystal structures

Reaction of the pyrrolidine dienamine of 4a-methyl-Δ1,8a-2-octalone with methyl vinyl ketone occurs primarily across the 8,8a-positions in methanol to provide the first synthesis of 10-methyltricyclo[8.4.0.01,6]tetradecane-3,13-dione (5), whereas in toluene reaction occurs across the 3,8a-positions to give 11-acetyl-6-methyltricyclo[6.2.2.01.6]dodecan-9-one (6), the stereochemistry of both structures being determined by X-ray analysis.

New mode of bonding of a vinyl ligand to an osmium cluster: the X-ray crystal structure of [HOs3(CO)10(CF3CCHCF3)]

The reaction of [H2Os3(CO)10] with CF3CCCF3 in hexane at room temperature leads to the formation of [HOs3(CO)10(CF3CCHCF3)]; a single crystal X-ray analysis reveals that the organic fragment is bonded to all three Os atoms.

Crystal and molecular structures of bis{tetracarbonyldiphenylmethylphosphinemanganese(0)} and bis{tetracarbonyldimethylphenylarsinemanganese(0)}

In the molecule [Mn2(CO)8(PMePh2)2], the phosphine ligands are attached axially, but in [Mn2(CO)8(AsMe2Ph)2] the arsine ligands are attached equatorially.