Michael Laing

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.

X-Ray structure of the non-classically bonded carbonium ion [{(η5-C5H5)Fe(CO)2}2(C3H5)]+

In the cation [{(η5-C5H5)Fe(CO)2}2(C3H5)]+, each Fe atom is joined by a strong β-bond to a CH2 group and by a weak link to the β-CH group of the allylic system.

A new atisane diterpene: ent-16α-hydroxyatis-13-en-3-one from Androstachys johnsonii prain

The title diterpene, a rare example of the naturally occurring ent-atis-13-ene type, has been isolated as the 2-benzylidene derivative from the heartwood hexane extract of Androstachys johnsonii Prain. Its structure was determined by n.m.r. and X-ray crystallography. It is suggested that the title compound is biogenetically produced from an ent-12-oxybeyer-15-ene precursor. An interesting reaction reported here was found to convert a vicinal diol into a monoketone using the diethyl azodicarboxylate–triphenylphosphine–benzoic acid system.

[{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.

The structure of primary nickel dithizonate.

Primary nickel dithizonate is found to be isostructural with the palladium and platinum complexes, and the nickel dithizonate molecule is shown to contain nickel in an approximately square planar configuration bonded to the organic ligand through both sulphur and nitrogen atoms.

The O–O bond length in oxygen adducts of iridium and rhodium complexes

The O–O bond length in dioxygen complexes of Rh and Ir compounds lies in the range 1·45–1·50 A; the long bond of 1·625 A reported for [IrO2(dppe)2]+ is an artefact caused by crystal decomposition.

The crystal and molecular structure of trans-bis(diphenylmethylphosphine)tricarbonyl manganese hydride

Abstract The phosphine ligands in HMn(CO) 3 (PMePh 2 ) are trans -substituted; the trans pair of CO groups are markedly distorted from colinearity.

[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.

The crystal and molecular structure of the triphenylboron adduct of dicarbonyl-π-cyclopentadienyliron cyanide

Abstract The complex [(π-C 5 H 5 )Fe(CO) 2 CNB(C 6 H 5 ) 3 ] contains a FeCNB bonding arrangement.

Powder Diffraction Analysis of Urinary Calculi: The Advantages of Using a Cobalt X-Ray Tube

Abstract An improvement in dispersion of the diffraction lines and a considerable reduction in the irradiation time can be obtained by using cobalt Kα radiation.