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A number of optically active coronands incorporating sulfoxide and sulfoximine functionality have been prepared and their association constants for complexes with alkali metal and ammonium picrates have been measured. Some of these complexes have association constants greater than 70000 1. mol-1 with selectivity for lithium and sodium cations, but no stereoselectivity has been observed for complexes with racemic ammonium guests. The X-ray crystal structure of one of the sulfoxide coronands is reported.

Chiral inductions in the C- methylations of four optically active N-ethoxycarbonylmethyl-S-p-tolylsulfoximines were explored by using the reagents lithium diisopropylamide (in tetrahydrofuran at -78°) then methyl iodide. When the fourth substituent at sulfur was a methyl group, complex mixtures of products were formed. However, when the fourth substituent was an aryl group, moderate yields of methylated compounds were formed and the ratio of diastereomers produced were 50 : 50 ( Ar = phenyl), 76 : 24 ( Ar = o- methoxyphenyl ) and 100 : 0 [ Ar = o-(2-methoxyethoxy)phenyl]. The diastereoselectivities are accounted for by intramolecular chelation of the aryl-oxygen substituents with the intermediate lithiated carbanion. The structure and absolute configuration where Ar = o-(2-methoxyethoxy )phenyl were confirmed by X-ray crystallographic methods. Space group P 212121, orthorhombic, a 10.2500(7), b 13.281(2), c 16.526(2) Ǻ; final R 0.064 (on 924F). The configuration at the sulfur atom is (S) and that induced at the carbon atom is (R).

Reactions of sulfoximines with sodium hydride in dimethylformamide, then with a variety of alkyl halides afford N- alkylsulfoximines. Generally yields are in excess of 60% under optimal temperature conditions (60°).

A complex between palladium(II) chloride and the optically active podand , (S,S)-1,5-bis[o-(p- toluenesulfinyl ) phenoxy ]-3-oxapentane, has been prepared and is shown to contain two equivalents of palladium(II) chloride to one equivalent of the podand. Crystal structure analysis shows each of the sulfur atoms in the sulfoxide groups is coordinated to a palladium atom, and the palladium atoms are also linked through chloride bridges. Crystal data: a 14.878(2), b 17.226(3), c 8.178(1) Ǻ, β 103.30(1)°; P21; Z 2.

Using novel synthetic lipids, a tethered bilayer membrane (tBLM) was formed onto a gold electrode such that a well-defined ionic reservoir exists between the gold surface and the bilayer membrane. Self-assembled monolayers of reservoir-forming lipids were first adsorbed onto the gold surface using gold−sulfur interactions, followed by the formation of the tBLM using the self-assembly properties of phosphatidylcholine-based lipids in aqueous solution. The properties of the tBLM were investigated by impedance spectroscopy. The capacitance of the tBLM indicated the formation of bilayer membranes of comparable thickness to solvent-free black (or bilayer) lipid membranes (BLM). The ionic sealing ability was comparable to those of classical BLMs. The function of the ionic reservoir was investigated using the potassium-specific ionophore valinomycin. Increasing the size of the reservoir by increasing the length of the hydrophilic region of the reservoir lipid or laterally spacing the reservoir lipid results in an improved ionic reservoir. Imposition of a dc bias voltage during the measurement of the impedance spectrum affected the conductivity of the tBLM. The conductivity and specificity of the valinomycin were comparable to those seen in a classical BLM.

A series of 8-substituted 19-methoxy-17-methyl-3,6,10,13- tetraoxabicyclo[13.3.1]nonodeca-1(19),15,17-trienes has been prepared and their complexations with alkali metal and ammonium cations studied. When the 8-substituent contained sulfide functionality weak complexes formed, but hosts with lariat sulfoxide substituents formed complexes- with greatest specificity for lithium ions.

A number of polyether coronands incorporating sulfide and sulfoxide functionality and five or six ether oxygen atoms were prepared, their formation of complexes with alkali metal and ammonium salts were studied and the results were compared with analogous phosphorus- containing coronands reported previously. It is evident that ring size played a more important role than the ability of a group to complex in systems with five ether oxygen atoms in which the sulfide-containing coronands actually formed stronger complexes than the corresponding sulfoxide coronands . When the number of ether oxygen atoms in the ring was six, however, it appeared that complexation occurred with the ether oxygen atoms and little contribution came from the sulfur centres.

A series of optically active podands incorporating ether and chiral sulfoxide functionality have been synthesized. The podands formed relatively strong complexes with protonated amines. Where racemic guests were used, the diastereoisomeric complexes were identified in solution by 1H n.m.r. spectroscopy but the energies of formation of these complexes were too similar to afford optical resolution of guests. The podands influenced the stereochemistry of t-butoxide-catalysed additions of methyl 1-oxoindane-2-carboxylate to methyl vinyl ketone, but stereoselectivities observed were low.