The quantitative treatment of interfacial stability in crystal growth from the vapour phase, presented in a previous paper, has been extended to cover (1) large temperature differences between source and seed, (2) arbitrary temperature profiles, and (3) an inert third species in the gas phase. The effect on the growth rate and critical growth rate of altering the temperature profile has been investigated and found to be small if the slope at the growing interface is above about 10 K cm–1. The influence of small quantities of inert gas on the temperature difference corresponding to the critical growth rate is shown to provide a useful stabilising effect against unavoidable temperature fluctuations. At the same time, the partial pressure ratio α of the active components becomes a less sensitive function of the distance along the growth capsule. The treatment is general; however, the familiar case of cadmium sulphide is included as an illustration and for comparison with our previous results.

The preparation and i.r. and n.m.r. spectra of the series of complexes cis-[PtX2(RNC)(PR13)](X = Cl, Br, or I; RNC = MeNC, EtNC, PhNC, or p-MeC6H4NC and PR13= PEt3, PEt2Ph, or PMe2Ph) are described. These complexes react with alcohols or primary amines under mild conditions to give carbene complexes of the type cis-[PtCl2{C(Q)NHR}(PR13)](Q = OMe, OEt, or OPri, NHPh, NHMe, NHEt, or NHBus and R = Ph or Me). The i.r. spectra and structure of these complexes are discussed. The isonitrile complexes give hydrocarbons on reduction which must originate from the isocyanide carbon atom. No other products of reduction could be characterised.

The MINDO/1 method has been used to study barriers to inversion of trivalent nitrogen, keto–enol tautomerism, and chelation by hydrogen bonding in enols from β-dicarbonyl compounds. The results seem to agree quite well with experiment.

The syntheses of some nickel and cobalt complexes containing terdentate Schiff base ligands (L), having the donor atom set N2S, are described. The ligands are derived from pyridine- or pyrrole-2-carbaldehyde and o-aminobenzenethiol, or thiosemicarbazide or its 4-methyl analogue. The complexes are of the type [NiLCl], [Ni2L2], or [NiL2](in which only two donor atoms, probably N, in each ligand are co-ordinated to the metal), and [CoL2]+(in which all three donor atoms of the ligand are co-ordinated to the metal). Attempts to prepare binuclear complexes of the type [Co2L2] are described. The complexes were characterised by electronic, mass, and n.m.r. spectroscopy; these data were used to predict their structures.The electrochemical properties of the complexes were investigated in dimethylformamide by polarography and cyclic voltammetry. The nickel complexes generally underwent one oxidation, and at least one, and more often two reduction processes, which were usually irreversible. The cobalt complexes could be reduced polarographically in a reversible one-electron step giving [CoL2]0.

The adducts of 2,3,5,6-tetrachloroaniline, 2,4,6-tribromoaniline, pentafluoroaniline, 2-bromoaniline, and N-methylaniline with boron trichloride have been prepared and the elmination of hydrogen chloride from them in boiling benzene and in more basic solvents has been examined. Some kinetic measurements have been made. The first product of reaction in benzene, which is anilinodichloroborane for each amine except pentafluoroaniline, has been isolated and characterised. In no case was borazole isolated from reaction in boiling benzene. The compound 2-nitro-4-trifluoromethylanilinodichloroborane has also been characterised. The reaction of aromatic amines with BCl3 in general, and the possible mechanisms of formation of borazoles by elimination of hydrogen chloride from them are discussed.

Potential energy barriers hindering internal rotation for a variety of fluorinated ethanes have been determined from spectroscopic and ultrasonic measurements. The reasons for the observed discrepancies in values obtained from the two methods are discussed. When allowance is made for these uncertainties the agreement between the values obtained by these two techniques is reasonable.

The structure of 2-methoxy-cis-4,6-dimethyl-1,3,2-dioxaphosphorinan–borane has been determined by three-dimensional single-crystal X-ray analysis. The compound is orthorhombic, space group P212121, with a= 9·68 ± 0·03, b= 14·13 ± 0·05, c= 7·51 ± 0·03 Å, and Z= 4. The ring exists in a chair conformation, with an axial 2-methoxy group and two equatorial methyl groups. The mean P–O bond length is 1·562 Å; C–C distances range from 1·48 to 1·55 Å, and C–O distances from 1·47 to 1·51 Å. The structural results are compared with those for related phosphates.

The crystal structure of µ-formato-diethylenetriaminecopper(II) formate has been determined by X-ray diffraction methods and refined by full-matrix least-squares procedure. Z= 4 in the orthorhombic unit cell, space group Pnam, with a= 8·954, b= 11·640, and c= 9·676 Å. There are no discrete [Cu(dien)(HCO2)]+ ions in the crystal; chains of ions are formed parallel to a, the copper atoms being linked by formate groups in an anti–syn bridging arrangement. Each [Cu(dien)(HCO2)] group possesses mirror symmetry (space-group imposed) and the copper atom environment is essentially square-pyramidal. One oxygen atom co-ordinates to the copper atom at 2·035 Å in the plane of the three equal copper–nitrogen bonds (2·012 Å) and the apical position is occupied by a second oxygen atom 2·169 Å from the copper atom.

The i.r. spectra of various (π-ring)M(CO)2X complexes of chromium, manganese, and iron have been investigated in the regions 225–700 and 1850–2100 cm–1. Absorption bands due to vibrations of the (π-ring)M(CO)2 moieties are reported and assigned. Trends in frequencies and relative intensities of those bands which are due largely to the δ(MCO) vibrations are discussed, and shown to depend on the ligand X.

The chelating agent o-carboxyphenyldimethylarsine and its diphenyl and di-p-tolyl analogues form complexes (R2As路C6H4路CO2)2M where R is methyl, phenyl, or p-tolyl and M is CoII or NiII. The complexes of cobalt(II) with R = Me and Ph and of nickel(II) with R = Ph and p-C6H4Me have been assigned an octahedral stereochemistry with the help of i.r., reflectance, and magnetic data. The results of these measurements in the case of complexes of nickel(II) with o-carboxyphenyldimethylarsine are, however, in favour of a tetrahedral structure.

The formation of bis-(2,2,6,6-tetramethylheptane-3,5-dionato)palladium by reaction of the β-diketone with disodium hexachlorodipalladate in methanol appears to involve the intermediate formation of di-µ-methoxy-bis-(2,2,6,6-tetramethylheptane-3,5-dionato)dipalladium. Under suitable conditions this compound becomes the sole product and it has been isolated and characterized.

The complexes trans-[(C6H11)3P]2NiHX and trans-(Pr13P)2NiHX (X = halogen, SCN, or CN) have been prepared. Their stability is discussed.

The autoxidation of hydroxylamine in aqueous alkali is shown to proceed by attack of oxygen on a deprotonated species yielding nitroxyl ion which can be oxidised further to peroxonitrite. In the presence of a metal sequestering agent (edta) the peroxonitrite ion is stabilised, although isomerising slowly to nitrate. A little nitrite is also formed. Decrease in pH leads to increasing production of gaseous products. In the presence of catalytic metal ions, nitrite is the main product, the hydroxylamine being largely consumed via reaction with peroxonitrite. Increasing concentration of copper(II) ions resulted in increasing production of nitrous oxide. A mechanism is presented for oxygen attack on hydroxylamine and a number of other autoxidation studies on N- and O-substituted hydroxylamines discussed.

The 35Cl nuclear quadrupole frequencies of 23 boron-chlorine compounds are presented and discussed in terms of the s-character and charge distribution in the B–Cl band. An approximate order of donor ability for a ligand L in compounds of the type BCl3,L is proposed on the basis of the 35Cl frequencies.

CNDO/2 MO calculations have been carried out to investigate the effect of distortions of the hydrogen bond in the open water dimer. Linear dimers of water are more stable when the O–H vector is not directed towards the lonepair orbital of the donor oxygen atom, the stability being maximum when the hydrogen is in between the two lonepair orbitals. Bending the hydrogen bond in the water dimer markedly decreases hydrogen-bond energy and increases the dimer energy when the angle of bend is greater than ca. 30°.

Di-µ-organothio-(bis-π-cyclopentadienyltitanium)tetracarbonyls of Group VI, (π-C5H5)2Ti(SR)2M(CO)4(R = Me or Ph; M = Cr, Mo, or W), have been prepared by ligand-exchange reactions. Their i.r., 1H n.m.r., and electronic spectra provide evidence for appreciable metal–metal bonding.

U.v. irradiation of a benzene solution of triphenylphosphine and dicarbonyl-π-cyclopentadienylnitrosylmolybdenum yields approximately equal quantities of the simple substitution product carbonyl-π-cyclopentadienylnitrosyl(triphenylphosphine)molybdenum, [(π-C5H5)Mo(CO)(NO)(PPh3)](I), and a complex shown by a three-dimensional X-ray crystal-structure analysis to be isocyanatocarbonyl-π-cyclopentadienylbis(triphenylphosphine)molybdenum, [(π-C5H5)Mo(CO)(PPh3)2(NCO)](II). Irradiation of the azide [(π-C5H5)Mo(CO)(PPh3)2N3] under an atmosphere of carbon monoxide, and of the azide [(π-C5H5)Mo(CO)2(PPh3)N3] in the presence of triphenylphosphine, gives mixtures of [(π-C5H5)Mo(CO)(PPh3)2(NCO)] and [(π-C5H5)Mo(CO)2(PPh3)(NCO)]. These reactions are consistent with the formation of organometallic nitrenes which capture carbon monoxide to produce the isocyanate ligand. The methylene chloride solvate of (II) crystallizes in the monoclinic space group P21/c, with a= 16·65, b= 13·21, c= 18·14 Å, β= 90°12′, and Z= 4, and has ca. 0·5 molecule of CH2Cl2 to each molecule of (II). The atoms were located in electron-density distributions and the co-ordinates and isotropic thermal parameters adjusted by least-squares calculations, the final value of R being 0·114 over 5606 independent reflections. The molybdenum atom, formally seven-co-ordinate, may be described as being at the central position of a distorted square pyramid, with the cyclopentadienyl ring at the apex and the other ligands at the corners of the base. The MoNCO grouping is closely linear, the Mo–M–C and N–C–O angles being 178·3 ± 0·9° and 179·1 ± 1·2°, respectively. The Mo–NCO distance is 2·127 ± 0·008 Å and the Mo–CO distance 1·934 ± 0·010 Å. The Mo–P bond lengths are 2·497 and 2·500 (±0·003)Å. The Mo–C(cyclopentadienyl) distances range from 2·267–2·425 Å(±0·012 Å) and the mean value is 2·333 Å. In the single crystal subjected to X-ray analysis the phosphine ligands of (II) are in a trans relationship. The 1H n.m.r. measurements indicate that the bulk sample of photochemically generated complex (II) consists of a mixture of the cis- and trans-isomers.

Nitric oxide reacts with bis(pentane-2,4-dionato)palladium giving a mixture of 3-hydroxyiminopentane-2,4-dionato(pentane-2,4-dionato)palladium and bis-(3-hydroxyiminopentane-2,4-dionato)palladium. More convenient routes to both these compounds are discussed. An analogue of the latter compound derived from ethyl 2-hydroxyimino-3-oxobutyrate is described. The chemistry and spectra of these complexes are discussed in relation to their structures.

The mass spectra of P4Se3, P4S3, P4S5, P4S7, and P4S10 are reported; all exhibit molecular ions, but are otherwise dominated by even-electron ions, especially PS+, P3S+, and P3S4+. P3S+ and P3S4+ may possess the P4 and P4S3 structures respectively, but with S+ replacing P. The only abundant odd-electron ions other than molecular ions are P2S5+ and P2S3+, observed in the spectrum of P4S10; this indicates dissociation of P4S10 into P2S5 molecules in the vapour phase, consistent with the reported vapour density. The spectra of frozen melts of composition P4S7–10 provide evidence for the presence of P4S9 molecules but not P4S8 molecules.

Quantum yields (ϕ) have been determined for the photolysis of methylcobalamin in aqueous solution in the presence of air as follows: λ= 490 nm, ϕ= 0·35 ± 0·04; λ= 520 nm, ϕ= 0·32 ± 0·06; λ= 550 nm, ϕ= 0·24 ± 0·05. These results show that photolysis is initiated by the absorption of a quantum of radiation by the intense bands due to π–π* transitions localised within the conjugated corrin ring. Comparison of published data on the relative rates of photolysis under different conditions shows that the initial photolytic step is reversible, i.e., (i). Co–CH3 [graphic omitted] CoII+ CH3·(i)