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A series of aurocyanide and auricyanide complexes of phosphines, phosphine sulfides, and phosphine selenides were synthesized. These new complexes have the general formula [L n Au(CN) m ], where L could be Cy3P, (2-CN-Et)3P, Me3PS, Et3PS, Ph3PS, Me3PSe, or Ph3PSe. Auricyanide was reacted with L at 1 : 2 ratio. Products were characterized using elemental analysis, melting point, UV, IR, far-IR solution, and solid-state NMR spectroscopy. Phosphine ligands cause gold(III) reduction to gold(I); less redox tendency was found for phosphine sulfides and phosphine selenides. Tri-coordinate complexes [L2AuCN] were produced from phosphine ligands with gold-tetracyanide. IR and UV spectroscopic methods were used to identify gold oxidation state in the synthesized complexes.

Auricyanide [Au(CN) 4 ] − interaction with biologically important thiols, thioether and selenoether were carried out and monitored using 1 H, 13 C NMR and UV spectroscopy. These ligands include l -cysteine, glutathione, captopril, l -methionine and dl -seleno-methionine. Thiols show very strong affinity to be oxidized into the disulfide by auricyanide, which gets reduced to aurocyanide [Au(CN) 2 ] − . l -cysteine reaction mechanism with [Au(CN) 4 ] − was found to be dependent on reactants mole ratio. While l -methionine was completely inert toward auricyanide, dl -Se-methionine showed some reactivity with [Au(CN) 4 ] − after raising solution pH to 12 that facilitated cyanide exchange.

The interaction of [Au(en)Cl2]Cl with L-methionine (Met) and DL-seleno-methionine (Se-Met) was carried out in D2O solution at ∼pH 3.8.13C NMR spectra were interpreted by comparison with the spectra recorded after the reaction of Met or Se-Met with HAuCl4and also after oxidation by H2O2. Reactions of [Au(en)Cl2]Cl with Met and Se-Met were found to proceed through the exchange of chloride ligands from complex with Met or Se-Met. Gold(III) reduction takes place during the reaction andenligand was released from [Au(en)Cl2]Cl complex.

The stereoselectivity in the cyclodimerization of several six-membered cyclic nitrones has been investigated. The configurational/conformational analysis of the dimers (i.e. perhydrodipyrido[1,2-b;1′2′-e]-1,4,2,5-dioxadiazines) has been carried out by NMR spectroscopy. The NMR spectra of the dimers at lower temperatures indicated the presence of either a single or two invertomer(s). The nitrogen inversion barriers are determined using complete line–shape analysis. The invertomer ratios have been used to estimate the relative energies associated with the cis and trans ring fusion in these tricycles. A mechanistic rationale for the observed stereochemistry of the dimerization process has been presented. Copyright © 2009 John Wiley & Sons, Ltd.

A series of gold(III) metalacycle of five-, six- and seven-membered ring was prepared by reacting Auric acid (HAuCl4 � 3H2O) with 1 equiv. unsubstituted ethylenediamine (en), propylene diamine (pn) and butylenediamine (bn) ligands and with some N-mono-substituted as well as N,N 0 -disubstituted ethylene

The diastereoselectivity in the cycloaddition reactions of several mono- and disubstituted alkenes with a (-)norephedrine-derived methylenenitrone has been investigated. The stereochemical analysis of the addition products (i.e., isoxazolidines) has been carried out by X-ray, NMR, and chemical conversions. The NMR spectra of the isoxazolidines at low temperatures indicated the presence of either a single or a predominant invertomer. The stereochemistry of the invertomers and nitrogen inversion barriers are determined using complete line-shape analysis and their dependence on solvent is discussed. Copyright © 2008 John Wiley & Sons, Ltd.

The preparation and characterization of new mercuric complexes of formula L2Hg(CN)2 with L being imidazolidine-2-thione (Imt) and its substituted derivatives, 1,3-diazinane-2-thione (Diaz), 1,3-diazipane-2-thione (Diap), are described. The solution and solid-state 13 C NMR show a significant shift of the C S carbon resonance of the ligands, while the other resonances are relatively unaffected, indicating that most likely the solid-state structure is maintained in solution as well. The principal components of the 199 Hg shielding tensors were determined from solid-state NMR data. Antimicrobial activity studies of the free ligands and their complexes show that ligands exhibit substantial antibacterial activities compare to their Hg(II) complexes. © 2007 Elsevier B.V. All rights reserved.

Several complexes of AgCN with alkanediamine ligands (where the ligands are ethylenediamine, propane-1,3-diamine, butane-1,4-diamine, N , N ′-dimethyl-ethylenediamine, N , N ′-di- iso -propyl-ethylenediamine, etc.) have been synthesized and structurally characterized. In these species, alkanediamine ligands act as chelating ligands. The X-ray structure of the complex cyano-( N , N ′-di- iso -propyl-ethylenediamine)–silver(I) was determined. These complexes have been also characterized by IR, solution as well as solid-state NMR studies. There are two types of IR absorptions observed for mono and dinuclear complexes. For the mono nuclear complexes, a sharp CN band is observed between 2111 and 2131 cm −1 range, whereas for binuclear complexes the bands are in the range 2136–2140 cm −1 . The effect of the size of the ligands as well as their substituents is discussed. The antimicrobial activity studies of AgCN and its complexes show that the former exhibits substantial antibacterial activities compared to its complexes.

The preparation and characterization of zinc complexes of formula ZnL2X2 (X = Cl and Br), with L = 1,3-diazinane-2-thione (Diaz), 1,3-diazipane-2-thione (Diap), imidazolidine-2-thione (Imt) and its methyl and n-propyl substituted derivatives, are described. The complexes dichlorobis(1-methylimidazolidine-2-thione-S)-zinc(II) (1) and dichlorobis(1-propylimidazolidine-2-thione-S)-zinc(II) (2) have been characterized by single-crystal X-ray methods. Both complexes adopt distorted tetrahedral geometry. Only intramolecular hydrogen bonding interactions are observed in 1 and 2. Solution and solid state 13C NMR show a significant shift of the C=S carbon resonance of the ligands, while other resonances are relatively unaffected, indicating that most likely the solid state structure is maintained in solution. Antimicrobial activity studies of the free ligands and their complexes show that ligands exhibit substantial antibacterial activities compared to the complexes.

Complexation of Ag(+) with captopril, 1-[(2S)-3-mercapto-2-methylpropionyl]-L-proline, has been studied by (1)H and (13)C-NMR spectroscopy. The equilibrium constants for the trans to cis isomers of captopril bound to Ag(+) were measured by (1)H NMR spectroscopy. It is observed that the trans isomer of the drug binds more strongly to Ag(+) between pH 5 and 8, as shown by the broadening of the trans isomer's resonances in (13)C NMR spectra on complexation. A monodentate complexation of the trans captopril with Ag(+) via the thiol site is proposed based on the solid-state NMR and IR data. A superior antimicrobial activity is exhibited by the Cap-Ag(I) complex compared to captopril ligand itself against Heterotrotropic Plate Counts (HPC), Pseudomonas aeruginosa and Fecal streptococcus bacteria.

Two supported metallocene catalysts (CS 1: PQ 3030/MAO/Cp2ZrCl2 and CS 2: PQ 3030-BuGeCl3/MAO/Cp2 ZrCl2) were prepared by sequentially loading MAO and Cp2ZrCl2 on partially dehydroxylated silica PQ 3030. In catalyst CS 2, nBuGeCl3 was used to functionalize the silica. These catalysts were characterized by DR-FTIR spectroscopy, CPMAS NMR spectroscopy, and XPS. Their catalytic performance was evaluated by polymerizing ethylene using the MAO cocatalyst and characterizing the resulting polymers by GPC. Both catalysts produced two metallocenium cations (Cation 1: [Cp2ZrCl]+ and Cation 2: [Cp2ZrMe]+) with comparable equilibrium concentrations and showed varying solid-state electronic environments. The modified supports (PQ 3030/MAO and PQ 3030-BuGeCl3/MAO) acted as weakly coordinating polyanions and stabilized the above cations. BuGeCl3 did not affect the solid-state electronic environment. However, it increased the surface cocatalyst to catalyst molar ratio (Al:Zr), acted as a spacer, increased catalyst activity, and enhanced chain-transfer reactions. The separately fed MAO cocatalyst shifted the equilibrium between Cation 1 and Cation 2 toward the right. Consequently, more Cation 2 was generated, which acted as the effective and active single-site catalytic species producing monomodal PDI. Copyright © 2006 John Wiley & Sons, Ltd.

The single crystal X-ray structure of the compound [(Me3P-Au-Selenourea)22+ 2Cl−] has been determined. The [Me3P-Au-(selenourea)] units are dimerized and adopt a binuclear structure characterized by a metal–metal interaction (Au–Au:3.0386(5) A) and a torsion angle of 69.71(2)°. Hydrogen bonding takes place between the selenourea ligands and the chloride ions. The principal components of the 77Se, 31P and 13C shielding tensors were determined from solid-state NMR data.

Solid-state cross-polarization magic angle spinning 13C, 77Se and 15N NMR spectra were recorded for 1,3-imidazolidine-2-selenone, its N-substituted derivatives and some related compounds. The spinning sideband manifold intensities were used to obtain principal values of 13C and 77Se chemical shift tensors. Large selenium chemical shift anisotropies were observed for these selenones. Copyright © 2003 John Wiley & Sons, Ltd.

The amine salt, N,N-diallyl-N-carboethoxymethylammonium chloride was cyclopolymerized in water using ammonium persulfate as an initiator to afford a cationic polyelectrolyte which on acidic hydrolysis of the pendant ester groups gave the corresponding cationic acid salt (CAS). The CAS was converted into an anionic polyelectrolyte (APE) and polybetaine (PB). The solution properties of the APE having two basic functionalities were investigated in detail by potentiometric and viscometric techniques. Basicity constants of the amine as well as the carboxylate groups in APE are ‘apparent’ and as such follow the modified Henderson–Hasselbalch equation; as the degree of protonation (α) of the whole macromolecule increases, the protonation of the amine nitrogens and carboxylate groups becomes increasingly more difficult and easier, respectively. While the APE, PB and CAS were found to be soluble in salt-free water, the corresponding PB and CAS of the SO2 copolymers of the amine salt 1 were found to be insoluble in water.

The amine salt N,N-diallyl-N-5-carbomethoxypentylammonium chloride was copolymerized with sulfur dioxide in dimethyl sulfoxide with ammonium persulfate or 2,2'-azobisisobutyronitrile and afforded a cationic polyelectrolyte (CPE) with a five-membered cyclic structure on the polymeric backbone. The CPE, upon acidic hydrolysis of the pendent ester groups, gave a corresponding cationic acid salt (CAS) having the equivalent of chloride salt of 6-N,N-diallylammoniohexanoic acid as the monomeric unit. The CAS was converted into an anionic polyelectrolyte (APE) and a polybetaine (PB), having the monomeric unit equivalent of sodium 6-N,N-diallylaminohexanoate and 6-N,N-diallylammoniohexanoate, by treatment with 2 and 1 equiv of base, respectively. The solution properties of APE were investigated by potentiometric and viscometric techniques. The basicity constant of the amine functionality in APE was apparent and as such followed the modified Henderson-Hasselbalch equation; the protonation of the APE became more and more difficult as the degree of protonation of the whole macromolecule increased. The compositions and phase diagrams of the aqueous two-phase systems of APE and poly(ethylene glycol) were studied. The PB was found to be insoluble in water, and this paves the way for the potential use of APE in aqueous two-phase polymer systems for protein purification and its removal and recycling by conversion into PB.

The amine salt, N , N -diallyl- N -carboethoxymethylammonium chloride was copolymerized in dimethyl sulfoxide using ammonium persulfate or azo-bis-isobutyronitrile (AIBN) to afford the cationic polyelectrolyte (CPE) having five-membered cyclic structure on the polymeric backbone. The CPE on acidic (HCl) hydrolysis of the pendent ester groups gave the corresponding cationic acid salt (CAS) having the equivalent of chloride salt of N , N -diallylammonio ethanoic acid as monomeric unit. The CAS was converted into an anionic polyelectrolyte (APE) and polybetaine (PB) [having the monomeric unit equivalent of sodium N , N -diallylaminoethanoate and N , N -diallylammonioethanoate] by treatment with two and one equivalent of base, respectively. The solution properties of APE were investigated by potentiometric and viscometric techniques. Basicity constant of the amine functionality in APE is found to be ‘apparent’ and as such follow the modified Henderson–Hasselbalch equation; the protonation of the APE becomes more and more difficult as the degree of protonation ( α ) of the whole macromolecule increases. The composition and phase diagram of the aqueous two-phase systems of APE and poly(ethyelene glycol) (PEG) has been studied for the first time for this class of ionic polymers. The CAS and PB were found to be virtually insoluble in water.

Addition reactions of ethene onto several cyclic nitrones afforded [n,3,0]heterobicyclicalkanes devoid of any substituents in the ring skeleton. These fused ring systems with a bridgehead nitrogen, capable of undergoing nitrogen inversion, allowed us to determine the stereochemistry of the ring fusion and the thermodynamic stability of the cis, trans isomers. Some of the cycloadducts on peracid induced ring opening gave a new series of nitrones capable undergoing further cycloaddition reactions.

A series of trisubstituted hydroxylamine derivatives, both cyclic and acyclic, has been prepared. The energy barriers in these hydroxylamines are found to be dominated either by nitrogen inversion or N–O bond rotation depending on the nature of the substituents attached to the nitrogen. In several series of compounds, having XC6H4CH2 substituents attached to nitrogen, Hammett free energy correlations are obtained with positive ρ values, indicating increased electron density at the transition state for the inversion process. Isoxazolidines with C(5) ethoxy substituents demonstrate a strong anomeric effect.

A series of trisubstituted hydroxylamine derivatives, both cyclic and acyclic, has been prepared. The energy barriers in these hydroxylamines are found to be dominated either by nitrogen inversion or N–O bond rotation depending on the nature of the substituents attached to the nitrogen. In several series of compounds, having XC6H4CH2 substituents attached to nitrogen, Hammett free energy correlations are obtained with positive ρ values, indicating increased electron density at the transition state for the inversion process. Isoxazolidines with C(5) ethoxy substituents demonstrate a strong anomeric effect.

A series of beta-phenyl-2-isoxazolidineethanols having cis-disposed substituents at C(4) and C(5) has been prepared by asymmetric nitrone cycloaddition reactions and their NMR spectra recorded over a wide range of temperatures. The spectra in CDCl3 at low temperatures indicate the presence of two interconverting invertomers for some of the tri-substituted isoxazolidines. The effect of H-bonding--intramolecular in CDCl3 and intermolecular in CD3OD--on the population ratio of the nitrogen invertomers has been investigated. The nitrogen inversion barriers are determined using complete line-shape analysis, and their dependence on solvent is discussed.

A series of (betaR,5R)- and (betaR,5S)-2,5-disubstituted isoxazolidines: 5-(substituent)-beta-phenyl-2-isoxazolidineethanols, have been prepared by asymmetric nitrone cycloaddition reactions and their NMR spectra recorded over a wide range of temperatures. The spectra at low temperatures indicate the presence of the (betaR,5S) diasteromer almost exclusively as a single invertomer having trans disposition of the substituents at N(2) and C(5), while the (betaR,5R) diasteromer remained as a mixture of two interconverting invertomers in deuterated chloroform. The effect of H-bonding - intramolecular in CDCl(3) and intermolecular in CD(3)OD - on the population ratio of the invertomers and nitrogen inversion process has been investigated. The nitrogen inversion barriers are determined using complete line-shape analysis, and their dependence on solvent is discussed. Due to steric factor the trans-invertomers are found to be more stable than their cis counterparts.

Complexation of Ag+as AgNO3, solid AgCN and Ag(CN)2–by labeled and unlabeled L-methionine, DL-selenomethionine and d,l-thiomalate were studied by nuclear magnetic resonance methods. The13C NMR indicates that only Ag+react with the both L-methionine, DL-selenomethionine at neutral and higher pH via CO2–and S or Se atom forming a chelate. The Ag(CN)2–and AgCN do not bind to either of these two ligands at any pH. The Ag13CN, which is an insoluble polymer, can react with thiomalate to form chelate complexes at neutral pH. Various structures for the chelate formations are proposed.

Solid‒state NMR spectra were recorded for 1,3-imidazolidine-2-thione, 1,3-imidazolidine-2-selenone and some of their N-substituted derivatives. Spinning side-bands of thione and selenone carbons were analysed to yield chemical shift anisotropies for these carbons. The NMR spectrum of imidazolidine-2-thione (Imt) showed some evidence for the presence of thiol tautomer. Molecular computations were carried out for Imt and its N-methyl derivative to yield relative energies of various tautomers.

The copolymerization of sulfur dioxide with some alkenoic acids such as acrylic, 3-butenoic, 4-pentenoic, and 10-undecenoic acid was carried out using organic and aqueous media in the presence of (CH3)3 COOH/SO2 redox system. Elemental analysis, IR, and 13C-NMR revealed that the copolymers synthesized from the acrylic acid/SO2 system were of variable composition in organic media, but only polyacrylic acid homopolymer was formed in the presence of water. The other three alkenoic acid/SO2 systems gave always polysulfone copolymers of alternating structure regardless of the experimental conditions employed. Thermal analysis (TGA and DTA) of selected samples gave Tg in the 73–101°C, range Tm between 160 and 228°C, and the total weight loss in air from 31 to 97%. Flammability decreased as the S:C mole ratio increased. NMR shows that the complexation of SO2 with the CC part of all alkenoic acids is low.

The preparation is described of a series of benzylmethylamino-substituted fluorophosphoranes of general formula PhCH2(Me)NPF4–n R n (where R = Me, Ph; n = 0, 1, 2) from the cleavage of the silicon-nitrogen bond in benzylmethylamino-trimethylsilane by fluorophosphoranes. The structures of the new compounds are deduced from 1H, 19F and 31P nmr data. Variable temperature spectra give information about intramolecular exchange processes, and a detailed study was made of benzylmethylamino-diphenyldifluorophosphorane and of the corresponding 2-methyl-piperidyl compound.

Proton, 19F and 31P NMR studies of a number of tetra-, tri- and di-fluorodiazadiphosphetidines have yielded information about the barriers to pseudorotation at the phosphorus atoms. The data are classified according to the process studied, and are discussed in terms of the feasible exchange mechanisms. The PFR2 group is substantially more rigid than the PF2R group.

A series of chlorinated dimethyl tetrafluorodiazadiphosphetidines, [RF2PNMe]2, where R = ClCH2(I), Cl2HC (II), or Cl3C (III) have been studied. The syntheses of the two new members of this series, (II) and (III), are described. Analyses of the 31P-{1H} and 19F-{1H} noise-decoupled n.m.r. spectra yielded values for chemical shifts and coupling constants. In addition some 1H n.m.r. data are given, including results from computer-fitting for (II). The n.m.r. parameters and isomerism of the compounds are discussed.

The reactions of 2,2,2,4,4,4-hexafluoro-1,3-dimethyl-1,3-diaza-2,4-diphosph(V)etidine with NN′-dilithio-NN′-dimethylethylenediamine, and of the 1,3-t-butyl analogue with t-butyl-lithium gave rise to zwitterionic species, involving tetra- and hexa-co-ordinate phosphorus atoms, instead of the products of normal nucleophilic substitution in which phosphorus retains co-ordination number five. The zwitterionic structure of these products has been established by 1H, 19F, and 31P n.m.r. spectroscopy. Mass spectroscopy has shown that decomposition into monomeric phosphine imides, which is characteristic of 1,3-diaza-2,4-diphosph(V)etidines, does not occur in the case of the zwitterionic compounds.

Zeylasterone, a new triterpene from Kokoona zeylanica, is shown to be 2,3-dihydroxy-6-oxo-24-nor-D:A-friedo-oleana-1,3,5(10),7-tetraen-23,29-dioic acid-29-methyl ester (20 α) (1), the first member of a new series of phenolic 24-nor-D:A-friedo-oleanans.

A new bark acid, isochapelieric acid (cis-chapelieric acid), chapelieric acid, friedelin, friedelan-3β-ol, canophyllal, canophyllol, friedelan-3β,28-diol, canophyllic acid and amentoflavone have been isolated and characterized from leaf extractives of Calophyllum calaba. 13CNMR spectra of methyl chapelierate and methyl isochapelierate have been recorded and interpreted. Leaf extractives of Garcinia spicata afforded an unidentified long chain carboxylic acid, friedelin, friedelan-3β-ol, sitosterol and the biflavanones GB-1, GB-1a, GB-2a and morelloflavone. Chemotaxonomic significance of the occurrence of some of the above foliar constituents in Calophyllum and Garcinia species is discussed.

13 C and 31 P spin-lattice relaxation times ( T 1) and nuclear Overhauser effects were measured in triphenylphosphine, triphenylphosphine oxide, triphenylphosphine sulphide, and triphenylphosphine selenide, over a temperature, range −40°C to +55°C. Isotropic reorientation correlation times were calculated from the dipolar relaxation times for phosphorus and that for the para carbon. The spin-rotation mechanism is the dominant relaxation mechanism for phosphorus in triphenylphosphine, whereas the chemical shift anisotropy is the dominant mechanism in triphenylphosphine oxide at low temperatures. In triphenylphosphine sulphide and triphenylphosphine selenide, the dipolar and the chemical shift anisotropy mechanisms are important in phosphorus relaxation. The motional anisotropy of internal rotation of phenyl rings and overall tumbling is determined from the ratio of T 1 's of ortho or meta carbon to para carbon, and is found to increase with the decrease in temperature and with the increase in mol. wt. The angular momentum correlation times were calculated from phosphorus spin-rotation relaxation rates. From viscosity data, reduced correlation times were calculated and compared with that calculated using Stokes-Einstein-Debye, Gierer-Wirtz, and Hu-Zwanzig models.

The preparation of fluoro-phosphadiazetidinones, O[dbnd]C(NMe)(NEt)PF2R (R [dbnd] Me, Et, Ph), unsymmetrically substituted on nitrogen, from the reaction of tetrafluorophosphoranes with the silyl urea, O[dbnd]C(NMeSiMe3)-(NEtSiMe3) is described. The compounds undergo partial equilibration to the symmetric species, O[dbnd]C(NMe)2PF2R and O[dbnd]C(NEt)2PF2R. Low temperature 31P and 19F n.m.r. spectra indicate changes which are rationalized in terms of variations in the population of energetically different conformers and in the exchange rates between conformers. The conformational differences involved are those arising from pseudorotation at trigonal-bipyramidal phosphorus. Comparable n.m.r. data are also given for some related compounds.

1 H, 31P and 13C N.m.r. spectra have been obtained for a number of bis(phosphinoyl)amines (I) and bis(phosphinothioyl)amines (II). The spectra have been analysed to give chemical shifts and coupling constants, which are presented and discussed here. The sign of 2JPNP has been determined by heteronuclear spin tickling in several cases and found to be positive.

Explicit expressions for X transition frequencies in NMR spectra of [A[X]2]2 spin systems are derived for the case where one of the (A. X) coupling constants is much larger in magnitude than any of the other couplings, as is commonly encountered for molecules containing PF2 groups. The spectra to be expected are compared with those for the corresponding magnetic equivalence [AX2]2 case. Emphasis is placed on the determination of relative signs of coupling constants, and examples of spectra for fluorinated diazadiphosphetidines are discussed. Fur die Frequenzen der X-Ubergange der NMR-Spektren eines [A[X]2]2-Systems werden explizite Ausdrucke fur den Fall hergeleitet. daB eine der (A, X)-Kopplungskonstanten alle anderen betragsmaBig weit ubertrifft, wie dies fur die meisten Molekule der PF2-Gruppe der Fall ist. Die zu erwartenden Spektren werden mit denen eines [AX2]2-Spinsystems, bei dem magnetische Aquivalenz vorliegt. verglichen. Hierbei wird besonderer Wert auf die Bestimmung der relativen Vorzeichen der Kopplungskonstanten gelegt. Als Beispiele werden Spektren fluoreszierender Diazadiphosphetidine diskutiert.

It has been established by X-ray and n.m.r. analyses that the compund (Ph2FPNMe)n can be prepared as a dimer with a diazadiphosphetiding ring. The 1H spectrum of the NMe group may be explained in terms of a slow pseudorotation between two conformations. The two values of 3JPH(16.78 and 6.17 Hz) are considerably different, and involve coupling paths through axial and equatorial P–N bonds. Crystals of (Ph2FPNMe)2 are triclinic, space group P, with a= 9.849(2), b= 14.858(3), c= 8.236 (1)A, α= 93.53(2), β= 94.70(2), γ= 104.04(2)°, Z= 2. There are two independent crystallographically centrosymmetric molecules within the unit cell. Distorted trigonal-bipyramidal co-ordination is observed at phosphorus with mean bond lengths; P–F 1.683(3), P–N eq 1.652(3), P–Nax 1.780(1), and P–C 1.835(4)A. The Structure was solved by direct methods and refined to R 0.063 for 3 299 diffractometer-measured unique reflections.

NMR-spektroskopische Daten der Diazadiphosphetidine (III) werden ermittelt und im Hinblick auf mogliche Isomerie diskutiert.

The 19F n.m.r. spectra of a number of fluorinated cyclotriphosphazatrienes were measured and analysed, using iterative fitting by computer, to give the relevant coupling constants and chemical shifts. Some of the 31P spectra were also recorded and used in the computer iteration. The relationships of the n.m.r. parameters with molecular structure are discussed.

13C NMR spectra of 27-hydroxyfriedelane, kokoonol (27-hydroxyfriedelan-3-one) and kokoononol (27-hydroxyfriedelan-3,21-dione) have been recorded and signals assigned using the off-resonance decoupling, inversion recovery and lanthanide induced shift techniques.

Fluorine-19 and phosphorus-31 n.m.r. spectra have been obtained and analysed for a series of compounds of the type [graphic omitted]Me, mostly under conditions of proton decoupling. The data are discussed in relation to substituent effects.

The structure and possible structure, respectively, of a resveratrol dimer and tetramer (vaticaffinol) isolated from Vatica affinis Thw. have been elucidated on the basis of spectral data (u.v., i.r., 1H and 13C n.m.r. spectroscopy, high resolution mass spectrometry), chemical degradation, and biosynthetic considerations.