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Publisher Summary The chemistry of the boron trihalides has been extensively studied. These compounds are strong Lewis acids and form a wide range of simple 1 : 1 adducts that have served as model compounds for the study of Lewis acid-base interactions. Many reviews of their coordination chemistry have appeared and these are summarized in the more recent reviews appearing in the mid-1960s. In boron trifluoride adducts, fluorine displacement is relatively difficult, and thus, the widest range of adducts has been prepared for the trifluoride. As fluorine is replaced by successively heavier halogens, the displacement of halogen occurs more readily and secondary reactions of the initially formed donor-acceptor adducts become more important. Whereas the initial formation of a donor acceptor bond is a simple process, the secondary reactions of adducts need not be simple. Many such reactions, and related catalytic activity of donor-acceptor adducts of the boron trihalides, have been reported.

Carbon-13 n.m.r. data for a number of phenyl- and p-methoxyphenyl-tellurium compounds are reported. Variations in the chemical shifts and one-bond tellurium–carbon coupling constants are discussed in terms of the polarity of the tellurium–carbon bond. p-Methoxyphenyltellurium compounds show deviations from additive principles.

A mathematical model of an engagement between a Navy ship and a number of anti-ship cruise missiles is described. The model is designed to be used in Navy planning activities involving ship/cruise missile engagements. The engagement model described portrays the ship's defensive weapons as being rapid- fire guns and/or SAM systems, and allows for the portrayal of enemy jamming or other ECM activity. User-specified notions of partial damage to the ship's defensive weapons can also be accommodated. The outputs of the model are probability measures that the ship and each of the cruise missiles survive as functions of time. Inputs to the model are detailed performance characteristics of sensor systems, weapon systems and cruise missiles.

Reactions of halogenoalkanes with mixtures of potassium fluoride and a number of simple aromatic compounds capable of behaving as hydrogen-bond electron-acceptors give high yields of products in a short time; the reactions are thought to involve the transfer of electrons from fluoride to the aromatic molecule via the hydrogen bond.

19 F N.m.r. spectra of solutions of KF–18-crown-6 in a variety of organic solvents show ca. 6kHz line widths essentially indistinguishable from those of solid KF suggesting tight ion pairs or higher aggregates in solution.

The fast atom bombardment mass spectrum of a 1 : 1 mixture of cis-[Pt(NH3)2(OH2)2](CF3SO3)2 and guanosine 5′-monophosphoric acid demonstrates the existence of a cyclic Pt-N(7),α-OPO3 complex.

The hydrogen-bonded solvates formed between tetraethylammonium fluoride and a number of β-dicarbonyl compounds react at about room temperature with alkyl iodides to provide high yields of the mono-C-alkylated β-dicarbonyl products with no apparent contamination due to the formation of O-alkyl, dialkyl, or polymerisation products.

The complexes RHg(ox) (R = C6F5, p-HC6F4, or p-MeOC6F4; ox = quinolin-8- olate) have been prepared by reaction of thallous quinofin-8-olate with the appropriate organomercuric chlorides whilst PhHg(ox or meox), MeHg(ox),H2O, and MeHg(meox) (meox = 2-methylquinolin-8-olate) have been obtained from phenyl- or methyl-mercuric hydroxide and quinolin-8-ol or 2-methyl-quinolin-8-ol. Although MeHg(ox),H2O was readily dehydrated, the water could not be displaced by ligands (e.g. Ph3PO, Me2SO). Chelation of the quinolin-8-olate ligands (rather than unidentate O- bonding) was established for all complexes by ultraviolet/visible spectroscopy. Molecular weight data indicated that all complexes except MeHg(ox) and MeHg(ox),H2O are partly associated in benzene, chloroform and/or carbon tetrachloride [K(2 monomer ↔ dimer) in the range 1-40 mol-1 dm3]; this suggests an associated structure in the solid state. Some supporting evidence for associated structures was obtained by mass spectrometry. The structural conclusions are discussed in the light of crystal structures of PhHg(ox) and PhHg(meox) carried out in a concurrent investigation.

Heavy alkali-metal fluorides are soluble in low-molecular-weight liquid aliphatic diols. Low-field shifts in the proton magnetic resonances of selected fluoride–diol solutions may be interpreted as being due largely to strong hydrogen bonding between the fluoride anion and the diol hydroxyls, although cation effects are also evident. Variable-temperature 1H n.m.r. studies on KF–1,2-ethanediol, CH3CN–1,2-ethanediol, and neat 1,2-ethanediol have been carried out and values of –(50 ± 10) kJ mol–1 for ΔH⊖ and –(130 ± 25) J K–1 mol–1 for ΔS⊖ have been determined for the (F ⋯ HO)– hydrogen bond.

High resolution solid state 19F n.m.r. spectroscopy has been used for the first time to investigate the bonding in ionic fluorides.

The mass spectra for the series of compounds MexSn(NO3)4–x(x= 0–3) have been examined at 70 and 20 eV. The fragmentation patterns for the complexes are suggested with the aid of metastable-ion studies. Fragmentation paths are found to be similar to other alkyltin systems in that marked preference is shown for SnIV and SnII valence states in tin-containing fragments. Removal of the first nitrate group from the parent ion is accomplished by NO3 elimination; however, subsequent nitrate elimination proceeds, in part, via stepwise fragmentation of the nitrate group involving N–O bond rupture.

Proton–proton HCNH coupling in high pKaN-methylanilines can be observed in solutions containing strong hydrogen-bond electron donors.

Carbon-13 n.m.r. data for a number of phenyl- and p-methoxyphenyl-tellurium compounds are reported. Variations in the chemical shifts and one-bond tellurium–carbon coupling constants are discussed in terms of the polarity of the tellurium–carbon bond. p-Methoxyphenyltellurium compounds show deviations from additive principles.

A number of enolisable ketones undergo intermolecular self-condensation and cyclisation in the presence of fluoride. Fluoride encourages the enolisation of ketones, thereby providing an hydroxylic electron-acceptor site capable of forming strong H-bonds with the fluoride anion. The reactions of the H-bond-activated ketones are usually characteristic of enolate anions: aldol-type condensations and Michael reactions are observed.

The mercuric polybromobenzoates, (C6Br2CO2)2Hg, (XC6Br4CO2)2Hg (X = p-F, p-Cl, p-Me, o-Me, p-MeO or m-MeO) and (2,6-Me2C6Br3CO2)2Hg, and phenylmercuric pentabromobenzoate have been prepared by reaction of mercuric acetate or phenylmercuric acetate with the appropriate polybromobenzoic acids. Thermal decomposition of (C6Br5CO2)2Hg, (XC6Br4CO2)2Hg, (X = p-F, p-Cl or p-MeO) and C6Br5C02HgPh in boiling pyridine gave the new polybromophenylmercurials (C6Br&Hg, (XC6Br4)2Hg and C6Br5HgPh respectively, but similar treatment of (XC6Br4C02)2Hg (X = p-Me, o-Me or m-MeO) and (2,6-Me2C6Br3C02)2Hg yielded pyridine complexes of the mercuric carboxylates. Mercuric p-methyltetrabromobenzoate underwent decarboxylation in boiling nitrobenzenelpyridine giving (p-MeC6Br4),Hg, but the method could not be extended to (0-Mec~Br~C0~)o~r H(2g,6 -Me2C6Br,C02)2Hg. Decarboxylation of XC6Br4C02H (X = o-Me or m-MeO) was effected in molten mercuric trifluoroacetate giving, after treatment of the products with sodium chloride, the corresponding tetrabromophenylmercuric chlorides. All mercurials underwent cleavage with iodine or triiodide ions in hot dimethylformamide to give the corresponding iodopolybromobenzenes, and (C6Br5)2Hg was converted into C6Br5HgX (X = C1 or Br) by the corresponding mercuric halides in hot xylene/nitrobenzene. Thermal symmetrization of C6Br5HgX (X = C1, Br, or Ph) is detectable prior to melting, but (C6Br5),Hg is stable to at least 400'. The mass spectra of the polybromophenylmercurials are discussed.

We present the final analysis of an experiment to study the interaction of a beam of 670A MeV neon ions incident on a water column set to different thicknesses. The atomic number Z (and, in some cases, the isotopic mass A) of primary beam particles and of the products of nuclear interactions emerging from the water column close to the central axis of the beam was obtained for nuclei between Be (Z = 4) and Ne (Z = 10) using a time-of-flight telescope to measure the velocity and a set of silicon detectors to measure the energy loss of each particle. The fluence of particles of a given charge was obtained and normalized to the incident beam intensity. Corrections were made for accidental coincidences between multiple particles triggering the TOF telescope and for interactions in the detector. The background due to beam particles interacting in beam line elements upstream of the detector was calculated. Sources of experimental artifacts and background in particle identification experiments designed to characterize heavy ion beams for radiobiological research are summarized, and some of the difficulties inherent in this work are discussed. Complete tables of absolutely normalized fluence spectra as a function of LET are included for reference purposes.

Reactions of halogenoalkanes with mixtures of potassium fluoride and a number of simple aromatic compounds capable of behaving as hydrogen-bond electron-acceptors give high yields of products in a short time; the reactions are thought to involve the transfer of electrons from fluoride to the aromatic molecule via the hydrogen bond.

I.r. analysis of supported CuCN reagents suggests that the active forms of these materials in nucleophilic cyanations contain the ions Cu+ and Cu(CN)2–; this is the first report of an active solid form of CuCN.

Hydrogen bond assisted C- and O-alkylations, sulphenylations, and Michael additions have been carried out with the aid of fluoride ion immobilized on strongly basic anion exchange resins.

Tris(3,6-dioxaheptyl)amine (tdoha, industrial name TDA-1) is shown to complex with a series of alkali-metal cations in solution, complexation being observed by fast atom bombardment mass spectrometry (f.a.b.m.s.; observation of a metal–tdoha cation), i.r., and 19F n.m.r. Approximate values of the relative concentrations of the tdoha and crown ether complexes are obtained by f.a.b.m.s. by competitive complexation experiments with a range of cations.

Fast atom bombardment mass spectrometry (FABMS) has been used to investigate the hydrogen-bonding of pyridinium and trialkylammonium ions with a range of electron donors. We have studied the effects of matrix liquid, concentration, nature of the anion, and strength of the hydrogen-bond on the observed intensity of the complex peak. The results may be easily rationalized in hydrogen-bonding terms and are in excellent agreement with those of more ‘conventional’ techniques such as i.r. spectroscopy.

Reagent loading and drying conditions have been compared for alkali metal fluride (MF)–alumina supported reagents, by reaction studies and a series of analytical techniques. The reaction studies indicate that whereas a combination of low MF loadings and highly efficient drying procedures give the best reagents for catalytic reactions, somewhat higher loadings and more moderate drying conditions give the best reagents for non-catalytic reactions. The analytical studies enable some rationalisation of the reaction results as well as providing important clues concerning the nature of the active-basic species. The formation of OH– on the reagent surface cannot be entirely responsible for the high basicity of the reagents and it seems that co-ordinately unsaturated F– ions on the reagent surface play an important role in the behaviour of the reagents. High MF loadings and high drying temperatures result in significant structural damage to the reagents with resulting loss in activity.

The electron impact fragmentation of the trimethylamine adducts of BX3(X = H, F, Cl, Br, and I) and BFnBrm(n+m= 3) have been examined at 70 eV. Trends in ion abundances are evident as the atomic weight of the substituent halide increases. The results are discussed in terms of boron–nitrogen and boron–halogen bond strengths, with reference to the effects of boron–halogen π-bonding.

The mass spectra of a series of pentafluorophenyl derivatives of phosphorus have been examined. Bond-forming rearrangements were observed such as elimination of PF2 from the (C6F5)2P+ species giving (C6F4)2+, and elimination of successive molecules of FeF2 from [(C6F5)2PFe]2+. Some Group IV pentafluorophenyl derivatives and two pentachlorophenyl compounds were also examined.

Heats of formation of crystalline MX4,2L complexes (where M = Si, Ge, or Sn; L = pyridine or isoquinoline; X = F, Cl, or Br, except X = Cl only when M = Sn) have been measured calorimetrically. Values decrease in the order MF4 > MCl4 > MBr4, GeX4 > SiX4, and SnCl4 > GeCl4 > SiCl4, except that those for SiCl4,2py and SiBr4,2py are abnormally high. Comparisons are drawn with results from other sources and attempts are made to explain the observed orders.

Trimethylamine and 4-picoline adducts of the mixed boron trihalides have been identified in solution by 1H and 19F n.m.r. spectroscopy. All 20 of the possible boron trihalide adducts of trimethylamine have been detected. Halogen exchange to give the mixed boron trihalide adducts occurs only when an excess of boron trihalide is present. In contrast to the free boron trihalides and oxygen-donor adducts of the boron trihalides, the slow halogen redistribution in the nitrogen-donor adducts allows isolation of individual mixed-halogen species.