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From the deep violet, encrusting marine sponge Chelonaplysilla violacea, two rearranged spongian diterpenes, aplyviolene, (1R*,1′S*,3?aR*,5R*,6R*,8R*,8′aS*)-3-oxo-8-(1′,4′,4′-trimethyl-8′-methylenedecahydroazulen-1′-yl)-2,7-dioxabicyclo[3.2.1]oct-6-yl acetate (1), the acetoxy derivative, aplyviolacene (2), (5R*,8S*,9S*,10R*,13S*,14R* ,15S*,16R*)-spongian-15,16-diyl diacetate (3) and (5R*,8S*,9S*,10R*,13S*,14R*)-spongian-16-one (4) were isolated. The structures were determined by spectroscopic methods, and the structure of aplyviolene was confirmed by a single-crystal X-ray determination. The crystal structure was refined to a residual of 0.036 for 1125 independent observed reflections. The crystals were orthorhombic, space group P212121 with a 8.098(1), b 11.628(1), c 21.774(3)Ǻ.

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).

The crystal structure of the title compound, [Cu(C12H8N2)2I]I,S8, has been determined by X-ray diffraction at 295(1) K and refined by least squares to R 0.066 (2031 ?observed? reflections). Crystal data: orthorhombic, Pbcb, a 7.984(5), b 16.690(4), c 22.986(12) Ǻ, Z 4. The structure comprises five-coordinate trigonal bipyramidal [Cu(phen)2I]+ cations (I equatorial) lying on the 2 axes parallel to a which pass through the Cu-I bonds, together with iodide anions, and lattice S8 molecules, also lying on 2 axes but parallel to b. In the cation, Cu-I is 2.672(3), Cu-N (equatorial) 2.10(1) and Cu-N (axial) 2.00(1) Ǻ. S-S ranges from 2.004(7) to 2.059(7). There appears to be no significant interaction between the octasulphur molecules and any other species.

A new Boesenbergia species ( Zingiberaceae ) has been found to contain (+)-(1R,2S,3R,4S)-2-benzoyloxymethylcyclohex-5-ene-1,2,3,4-tetrol 4-benzoate [(+)- zeylenol ] (2)and the crotepoxide -related substance, (+)-(1R,2R,4R,5S,6R,7R)-4-benzoyloxymethy1-3,8-Dioxatricyclo [5.1.0.02,4]octane-5,6-diol 5-acetate 6-benzoate ( boesenboxide ) (8). The structure (8) was determined by spectroscopic, chemical, and X-ray crystallographic studies. Boesenboxide forms monoclinic crystals P21, a 12.722(2), b 5.23O(l), c 16.139(3) , β 106. 57(l); the crystal structure was refined to a residual of 0.029 for 1281 independent observed reflections.

The complexes [Mn ( mac )Cl2]+ [ mac = 1,4,8,1l-tetraazacyclotetradecane (cyclam), meso and rac-5,7,7,12,14,14-hexamethylcyclam ( teta and tetb respectively)] have been prepared. The trans-[ Mn ( teta )Cl2] Cl.3H2O complex crystallizes in the monoclinic space group P21 /c, Z 2, a 8.4006(8), b 12.465(2), c 11 .659(2) , β 103.20(1). The geometry about the manganese(III) is close to octahedral with the macrocycle coordinated to four equatorial sites ( Mn -N 2.043(2), 2.074(2) ) and chlorides in trans axial sites (Mn -Cl 2.549(1) . Since electronic spectra of the cyclam and teta complexes are similar, the ions should exist in similar geometries; however, the tet b analogue is spectroscopically unique, and the complex may adopt a different geometry. All complexes in water exhibit quasi-reversible one-electron couples near O V at a mercury electrode; irreversible reductions of manganese(II) are also observed before the solvent limit near -1.5 V for the tetaand tet b complexes. No metal-centred oxidation waves are seen before the solvent limit (c.+ 1 V) at a platinum electrode. However, pulse radiolytic oxidation (with OH) of all complexes is observed with formation kf > 109 dm3mol-1 s-1; apparently d3 manganese(IV) monomers with electronic spectra qualitatively similar to d3 chromium(III) complexes are formed. Decay of these intermediates is first-order, with all kd ≥ 5×103 s-1, but varying with the macrocyclic ligand present. Alkyl substitution on the cyclam stabilizes the manganese(IV) oxidation state, the intermediate cyclam complex decaying 25 times faster than the teta analogue. The final decay product appears to be MnO2, and rate-determining ligand loss is presumed.

The cis -and trans-fused 1-benzyl-1,4,4a,5,6,7,8,8a-octahydro-3,2,1- benzoxathiazine 2- oxides and cis - and trans-fused 1-benzyl-2-phenyl-1,4,4a,5,6,7,8,8a-octahydro-2H-3,1,2-benzoxazaphosphorine 2-oxides have been prepared from the cis- and trans-2-benzylaminocyclohexanemethanols and their structures have been determined by n.m.r .and crystallographic methods.

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.

An X-ray crystallographic analysis of zinc(II) monoglycerolate has been carried out. The crystals are monoclinic, space group P21/c with a 8.110(1), b 6.404(1), c 8.714(2) β 93.44(1). The structure was refined by full-matrix least-squares techniques to an R factor (on 519F) of 0.019. The analysis reveals that the zinc atoms bridge the glycerolate molecules forming polymeric sheets lying parallel to the bc plane. Only aliphatic hydrogens are disposed into the space between the layers, a fact consistent with the lubricity and hydrophobic nature of the solid complex and the observed facile lamellar cleavage perpendicular to the a axis.

The anionic molybdenum(IV) cluster [Mo3S4(CN)9]5- has been subjected to X-ray crystal structure analysis. The potassium salt crystallized in the triclinic space group P1, a 10.634(1), b 11.888(3), c 24.892(2) , α 89.56(2), β 79.86(1), γ 76.53(2), Z 4. The three MoIV atoms in each unit of approximately CSL3v symmetry are situated at the corners of an equilateral triangle with Mo-Mo distance 2.765(7) . There are three S2- ligands bridging between pairs of Mo atoms, and a unique S2- ligand located uniformly above the plane of the equilateral triangle. Distorted octahedral coordination of each MoIV is completed by three CN- ligands to each of the three metal centres. The ion is structurally similar to the [MO3S(S2)6]2- precursor, and to [Mo3O4X9]n- analogues. In dimethyl sulfoxide, the cluster is irreversibly reduced in a single step near -2 V (v. saturated calomel electrode), but exhibits a quasi-reversible oxidation at + 0.51 V. On the coulometric time scale, the complex is irreversibly oxidized to MoV monomer.

The salts Ph4As [ReO(SPh)4].MeCN and Ph4As [ReO(SePh)4] have been synthesized and characterized. The crystal and molecular structure of the thiolate compound has been determined by X-ray crystallography which reveals a square-pyramidal arrangement of ligand atoms around the central rhenium atom of the [ReO(SPh)4]- anion. Crystal data: a 9.756(4), b 18.171(3), c 25.684(4) , space group P212121, Z 4.

The reaction [Co(dpt)Cl3]+ dien in propan-2-ol [dpt=di(3-aminopropyl)amine, dien = diethylene-triamine] gives mer-[Co(dpt)2]3+ and the three geometric isomers of [Co(dien)2]3+, almost quantitatively. The reaction [Co(dien)Cl3] + dpt in propan-2-ol, catalysed by water, yields the three isomers of [Co(dien)(dpt)]3+ as the main products, in the approximate ratio u-fac : mer : s-fac 4 : 2 : 1. Preparation of mixed amine complexes by substitution therefore requires that the amine (dien) forming the more stable complexes be incorporated in the reactant complex. The geometric structures of the isolated [Co(dien)(dpt)] (ClO4)3 isomers are assigned by 13C n.m.r. spectra. They each hydrolyse in water or base, the mer isomer rapidly, and no isomerization has been detected. X-ray crystallographic analysis of mer-[Co(dien)(dpt)]2 (S2O6)3,H2O,EtOH (from the isolated perchlorate by metathesis) confirms the assigned mer geometry. The two independent complex molecules in the asymmetric unit have different conformational geometries. The crystals are monoclinic, space group P21/c, with a 15.548(4), b 9.178(3), c 31.664(8) ,β 89,04(2). The structure was refined by blocked-matrix least-squares techniques to an R-factor (on 2752 F) of 0.058.

The 95MO n.m.r. spectra of a series of compounds containing the fac-[MoVIO3] and cis-[ MoVIO2] units are reported, together with those for the series [MoX2(R2NO)2] (X = O or S; R = Et, PhCH2). Trends in the data are discussed. The stereochemistry in solution of certain of the cis-dioxo species is assigned by means of 13C n.m.r. spectroscopy. The crystal and molecular structure of [MoS2(Et2NO)2],0.5C6H6 has been determined by X-ray crystallography. The steric and electronic requirements of the terminal sulfide ligands significantly affect the detailed coordination geometry relative to that observed for the dioxo analogue [MoO2(Et2NO)2]. Crystal data: a 10.162(2), b 11.836(2), c 14.437(2) , β 106.12(2) P21/a; Z 4.

mer-[Co(dpt)2] Cl3 [dpt = di(3-aminopropyl)amine] has been obtained from substitution or oxidation reactions in non-aqueous solvents, and transformed to the perchlorate salt. The different form of the 13C n.m.r. spectrum to that of mer-[Co(dien)2]3+ (dien = diethylenetriamine), and variation of the spectrum with basicity, is taken to indicate high conformational mobility of the coupled six-membered chelate rings of the mer structure. Slow hydrolysis occurs in neutral water (but is prevented by acid), and the hydrolysis product has been isolated. The s-fac and u-fac [Co(dpt)2]3+ isomers have not been detected chromatographically in the preparations, and any isomerization of the mer isomer is masked by the hydrolysis. X-ray crystallographic analysis shows that the isolated hydrolysis product is the racemic geometric isomer (C2 symmetry) of [(dpt)Co(OH)3Co(dpt)] (ClO4)3. Each facially coordinated dpt adopts the ring conformations chair, irregular-boat. The crystals are monoclinic, space group P21/n, with a 15.053(5), b 13.964(2), c 14.010(3) , β 109.90(2). The structure was refined by blocked-matrix least-squares techniques to an R factor (3190F) of 0.032.

Reactions between RuCl(Pme3)2(η-C5H5) and unsaturated hydrocarbons in the presence of NH4PF6 have given [Ru(η2-un)(PMe3)2(η-C5H5)] PF6[un = C2H4, (E)-CH(CN)=CH(CN),CH2=CHCH=CH2, CH2=C=CH2, CH2=C=CMe2, C2Ph2, PhC2C2Ph, PhC2CO2Et, C2(CO2Me)2 and C2(CF3)2]. The molecular structures of the buta-1,3-diene (3) and allene (4) complexes have been determined. In both compounds, the unsaturated hydrocarbon is bonded to ruthenium in an asymmetric η2 mode: Ru-C 2.185, 2.242(5) [for (3)], 2.084, 2.172(6) [for (4)l; coordinated C=C 1.386(8), 1.394(8) A, respectively. The allene skeleton is bent by 35 at the central carbon. Crystal data: (3) monoclinic, P21/n, a 17.343(2), b 13.692(4), c 17.997(3) , β 94.91(1), Z 8; (4) orthorhombic, Pca21, a 18.999(3), b 9.253(3), c 23.016(6) , Z 8. The structures were refined to residuals of R 0.026, R, 0.028 for 4076 data with 1 > 2.5σ(I) [for (3)], and R 0.022, Rw 0.024 for 3054 data [for (4)].

X-ray crystallographic analysis shows that the isolated [Co(dpt)2](ClO4)3 [dpt = di(3-aminopropyl)-amine] is the mer geometric isomer. All four six-membered chelate rings of the complex adopt flattened chair conformations, and substantial internal strain is evident in the structure. The crystals are monoclinic, space group P21/c, with a 15.259(3), b 10.646(2), c 15.367(3) , β 9935(1). The structure was refined by blocked-matrix least-squares techniques to an R factor (on 1731 F) of 0.042. A molecular mechanics study of the [Co(dpt)2]3+ system shows that the structure (geometric isomer and conformer) having the lowest strain energy is mer-(chair, chair, chair, chair) which is that observed in the solid state, and predicts its coexistence in solution with several other conformers, particularly mer-(chair, chair, chair, λ-skew) and mer-(chair, chair, δskew, chair). The calculated isomer proportions are meru-fac > s-fac in accordance with the experimental observation of the mer only. The substantially higher strain energy of the mer isomer compared to mer-[Co(dien)2]3+ accounts for the tendency to hydrolysis of mer-[Co(dpt)2]3+.

The crystal structure of the title compound, Ca(C6H2N307)2,5H2O, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.049 for 1513 'observed' reflections. Crystals are orthorhombic, Pmab, a 24.169(6), b l0.292(7), c 8.554(2) , Z 4. The stereochemistry about the calcium has not been observed previously for the system [M(bidentate)2- (unidentate)4]; in the present structure, the calcium is coordinated by a pair of bidentate picrate ligands and the four water molecules in an array in which three of the water molecules occupy a triangular face of a square antiprism, the overall array having m symmetry. The remaining water molecule occupies a lattice site with no close interaction with the other species.

The structure of ?[Th(CF3COCHCOCH3)4]? has been redetermined from diffractometer data and shown to be [Th(CF3COCHCOCH3)4(H2O)]. The stereochemistry is in agreement with that determined for the [M(bidentate ligand)4(unidentate ligand)]x system by a calculation based on a repulsion model.