Peter Pauling

The structure of bis-pyridine metal dihalide complexes

Abstract The structures of complexes of the type M II (Hal) 2 . 2 Pyridine have been investigated by a variety of physical techniques. Particular attention has been paid to the cobalt complexes which can exist in one or both of two isomeric forms. The factors which decide whether the tetrahedral monomer or octahedral polymer form will be the more stable are discussed. By using various metals five different types of complexes of the above formula have been identified — (a) tetrahedral monomer; (b) octahedral polymer; (c) square planar monomer; (d) tetragonal polymer; (e) (presumably) irregular tetrahedral monomer. The influence of the electronic configuration of the metal and the effect of the ligand on the structure adopted are discussed.

Co-ordination of Transition Metals by the Perchlorate Ion: The Crystal Structure of Co(Ph2MeAsO)4(CI04)2

As reported by Lewis, Nyholm and Rodley (preceding communication), diphenylmethylarsine oxide (Ph2MeAsO) forms a series of complexes with the metal II perchlorates of manganese, iron, cobalt, nickel, copper and zinc. The magnetic properties of this series, together with their absorption spectra in the ultra-violet, visible and infra-red regions, are discussed by those authors. Since the structural implications of these physical properties were not entirely conclusive, we have undertaken a structure analysis of the cobalt compound by single crystal X-ray diffraction techniques.

Conformation of acetylcholine at muscarinic nerve receptors: Crystal and molecular structure of 2-trimethylammoniummethyl-5-methyl furan iodide (5-methylfurmethide iodide)

Abstract 2-Trimethylammoniummethyl-5-methyl furan (5-methylfurmethide) is a potent cholinergic agonist at muscarinic nerve receptors. The conformation of the molecule, as shown by crystal structure analysis, is restricted by steric hindrance. The only similar conformation of acetylcholine has τ(N+CCO) synclinal and τ(CCOC) antiplanar. This is the conformation found in solution and in crystals of the chloride, and it is believed to be the one relevant to interaction with muscarinic nerve receptors.

Neuromuscular blocking agents: Structure and activity

Abstract Correlation of crystal structure analyses and model building of rigid molecules indicate the structural requirements for curariform activity and the structural differences between depolarizing and non-depolarizing neuromuscular blocking agents.

Molecular Structure of LSD

The molecular configuration of lysergic acid diethylamide (LSD) in crystals of the iodobenzoate has been determined by using x-ray diffraction techniques. The configuration shows strain and steric hindrance and the conformation is fixed. Some of the implications of this for the hallucinogenic activity of LSD are discussed.

The crystal structure of (–)-(S)-hyoscine hydrobromide

The structure of (–)-(S)-hyoscine hydrobromide (scopolamine hydrobromide) has been determined.

Crystal structure and absolute configuration of (R)-(–)-3-acetoxyquinuclidine methiodide

The structure and absolute configuration of the title compound has been determined by single-crystal X-ray diffraction. Crystals are triclinic with Z= 1 in a unit cell of dimensions a= 7·610(4), b= 7·410(4), c= 6·909(3)A, α= 69·75(3), β= 111·88(3), γ= 112·38(3)°, space group P1. The structure was solved by Patterson and Fourier methods and refined by least-squares by use of 1637 observed three-dimensional diffractometer data to R 0·045. The absolute configuration was determined by use of the anomalous scattering effect of the iodine atom. The quinuclidine cage is twisted by ca. 12° and the ester group is planar.

The preparation and crystal structure of tristriphenylphosphinetriphenylarsinerhodium(I) hydride, (Ph3P)3(Ph3As)HRhI,½C6H6

Crystals of tristriphenylphosphinetriphenylarsinerhodium(I) hydride are isomorphous with those of tetrakistriphenylphosphinerhodium(I) hydride with the arsenic and phosphorus atoms randomly occupying the four tetrahedral heavy-atom-ligand positions and the hydrogen atom trans to both arsenic and phosphorus.

Crystal structure of (pentafluorophenyl)(triphenylphosphine)gold(I)

The crystal structure of the title compound has been determined by single-crystal X-ray diffraction. Crystals are monoclinic, space group P21/c with Z= 4 in a unit cell of dimensions: a= 834·0(3), b= 1199·1(4), c= 2214·6(7) pm, β= 98·33°. Refinement of 1834 three-dimensional diffractometer data led to R 0·055. The gold atom is linearly co-ordinated, with C–Au–P 178°, Au–P 227(1) and Au–C 207(2) pm. The phenyl and pentafluorophenyl rings are planar and their bond distances and angles have the expected values. The structure is compared with other bisco-ordinated gold compounds containing Au–C or Au–P bonds.

Crystal and molecular structure of trans-4-aminocrotonic acid

Crystals of the title compound are monolclinic, space group P21/c, a= 8.863(3), b= 7.870(2), c= 14.971(5)A, β= 115.37(3)°, Z= 8. The structure was solved by direct methods and refined by least-squares procedure to a value R 0.048 for 1 834 observed diffraction maxima. The location of all hydrogen atoms (difference-Fourier synthesis) shows that the molecules are zwitterions linked by a three-dimensional network of hydrogen bonds.