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The nonheme iron(IV)-oxido complex trans-N3-[(L1)FeIV=O(Cl)]+, where L1 is a derivative of the tetradentate bispidine 2,4-di(pyridine-2-yl)-3,7-diazabicyclo[3.3.1]nonane-1-one, has an S = 1 electronic ground state and is the most reactive nonheme iron model system known so far, of a similar order of reactivity as nonheme iron enzymes (C-H abstraction of cyclohexane, 90 °C (propionitrile), t1/2 = 3.5 sec). The reaction with cyclohexane selectively leads to chlorocyclohexane, but “cage escape” at the [(L1)FeIII-OH(Cl)]+ / cyclohexyl radical intermediate lowers the productivity. Ligand field theory is used herein to analyze the d-d transitions of [(L1)FeIV=O(X)]n+ (X = Cl, Br, MeCN) in comparison with the thoroughly characterized ferryl complex of tetramethylcyclam (TMC=L2; [(L2)FeIV=O(MeCN)]2+). The ligand field parameters and d-d transition energies are shown to provide important information on the triplet-quintet gap and its correlation with oxidation reactivity.

The electrical conductivity, density and diffusion coefficients of trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide ([P66614][NTf2]) ionic liquid and its binary solutions in acetonitrile, propionitrile, dimethyl and diethyl carbonates were measured in the temperature range of 293 – 348 K. Electrical conductivity – ionic liquid mole fraction dependencies for the binary solutions were fitted with the empirical Casteel−Amis equation. The temperature dependencies of electrical conductivities were analyzed using the Arrhenius, Litovitz and Vogel-Fulcher-Tammann approaches. The activation energies and pre-exponential factor calculated using the Arrhenius equation for different mole fractions of ionic liquid were fitted with the empirical equations proposed in the literature. The thermo-gravimetric analysis combined with mass spectrometry demonstrated the high thermal stability of [P66614][NTf2] up to 600 K. At higher temperatures the decomposition of [P66614][NTf2] proceeds via the elimination of alkyl radicals as a result of the nucleophilic attack of reactive intermediates to [P66614]+ cation with the formation of trialkylphosphines. The activation energies of thermal destruction of [P66614][NTf2] were calculated using Kissinger equation and non-linear integral isoconversional model.

The synthesis of propionitrilium derivatives of cobalt and iron bis(dicarbollides) [8-EtCN-3,3′-M(1,2-C2B9H10)(1′,2′-C2B9H11)] (M = Co, Fe) by the reaction of the cesium salts of the parent bis(dicarbollide) anions [3,3′-M(1,2-C2B9H11)2]− with propionitrile in the presence of tert-butyl bromide is described. The nucleophilic addition reactions of water, alcohols, and thiols with the –N+C triple bond of the prepared nitrilium derivatives were studied and the corresponding iminols [8-EtC(OH)HN-3,3′-M(1,2-C2B9H10)(1′,2′-C2B9H11)] (M = Co, Fe), imidates [8-EtC(OR)HN-3,3′-M(1,2-C2B9H10)(1′,2′-C2B9H11)] (M = Co, R = Me, Et, i-Pr, Bu; M = Fe, R = Et), and thioimidates [8-EtC(SR)HN-3,3′-Co(1,2-C2B9H10)(1′,2′-C2B9H11)] (R = Et, Bu, Hx) were synthesized as mixtures of E and Z-isomers, some of which could be separated by the column chromatography on silica. The molecular structure of [(Z)-8-EtC(OiPr)HN-3,3′-Co(1,2-C2B9H10)(1′,2′-C2B9H11)] was determined by single-crystal X-ray diffraction study.

An efficient continuous flow sequential synthesis of diaryl ketones was achieved by coupling of aryl Grignard reagents with acyl chlorides in the bio-derived “green” solvent 2-methyltetrahydrofuran (2-MeTHF) under mild reaction conditions (ambient temperature, 1 hour), allowing a safe and on-demand generation of 2-(3-benzoylphenyl)propionitrile with a productivity of 3.16 g hour−1.

Understanding the factors that influence ion-solvent properties for the fluoride ion in organic solvents is key to the development of useful liquid electrolytes for fluoride-ion batteries. Using both experimental and computational methods, we examined a range of chemical and electrochemical properties for a set of organic solvents in combination with dry N,N,N-trimethylneopentylammonium fluoride (Np₁F) salt. Results showed that solvent electronic structure strongly influences Np₁F dissolution, and the pK_a of solvent protons provides a good guide to potential F⁻ reactivity. We found a number of organic solvents capable of dissolving Np₁F while providing chemically-stable F⁻ in solution and characterized three of them in detail: propionitrile (PN), 2,6-difluoropyridine (2,6-DFP), and bis(2,2,2-trifluoroethyl) ether (BTFE). Arrhenius analysis for Np₁F/PN, Np₁F/DFP, and Np₁F/BTFE electrolytes suggests that DFP facilitates the highest F⁻ ion mobility of the three neat solvents. Electrolyte mixtures of BTFE and amide co-solvents exhibit higher ionic conductivity than the neat solvents. This improved ionic conductivity is attributed to the ability of BTFE:co-solvent mixtures to partition between Np₁⁺ and F⁻ ion-aggregates, promoting better ion dissociation.

The effects of 3-(phenylsulfonyl)propionitrile (PSPN) as a higher voltage bifunctional additive in the electrolyte on the formation of a solid electrolyte interface (SEI) on both LiCoO2 cathodes and graphite anodes are investigated using the half-cell method. The capacity retention of the Li/LiCoO2 and Li/graphite batteries with PSPN ranges from 10.12% and 74.81% to 79.19% and 92.58% after 200 cycles, respectively. The results of linear sweep voltammetry (LSV) and cyclic voltammetry (CV) demonstrate that PSPN is not only preferentially reduced but also easily oxidized during the charge–discharge process. X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analyses confirm that PSPN-containing SEI films can form simultaneously on both electrodes due to the interaction of nitrile (–CN) and sulfur–oxygen double bonds (SO), providing protection to the LiCoO2 and graphite electrodes and improving the cycle performance at higher voltage.

p-Type dye sensitized solar cells (DSCs) have been assembled using the structurally unrefined, zwitterionic cyclometallated ruthenium dye [Ru(bpy) 2 (H 1 )] (H 3 1 = (4-(2-phenylpyridin-4-yl)phenyl)phosphonic acid) in combination with FTO/NiO photocathodes and an I 3 – /I – /acetonitrile (AN) electrolyte. Values of the short-circuit current density ( J SC ) = 4.06 mA cm –2 , open-circuit voltage ( V OC ) = 95 mV and photoconversion efficiency ( η ) = 0.139% are the highest achieved for state-of-the-art cyclometallated ruthenium dyes in p-type DSCs; data are confirmed using duplicate devices. J SC values are higher than those observed for the standard dye P1, and electrochemical impedance spectroscopy (EIS) shows that DSCs with [Ru(bpy) 2 (H 1 )] exhibit a both a lower transport resistance ( R t ) and recombination resistance ( R rec ) than DSCs with P1. Changing the electrolyte solvent from AN to propionitrile (PN), valeronitrile (VN), 3-methoxypropionitrile (MPN) or N -methylpyrrolidone (NMP) confirms a dependence of J SC on solvent in the order AN > PN > MPN > VN > NMP, whilst V OC follows the trend VN > PN > MPN > AN > NMP. The opposing trends in J SC and V OC lead to only a small drop in the overall η values for PN versus AN. EIS measurements revealed that although PN has a higher resistance to recombination reactions than AN, it also exhibits an increased amount of trapped charge carriers, leading to worsened DSC performance. DSCs based on AN do not remain stable over a 1-2 month period; both J SC and V OC decrease significantly. However, DSCs with the less volatile and more viscous PN show enhanced performance upon ageing with a gain in J SC over the first 33 days. Electrolytes with mixed solvents were investigated; addition of PN, VN or MPN to AN leads to lower J SC and this is most pronounced for VN and least marked for PN. The optimal solvent is an AN:PN mixture with volume ratios of 3:1 or 1:1; this mixed solvent results in enhanced long-term stability with respect to DSCs with pure AN and this is at the expense of a only small decrease in photoconversion efficiency

The ability of the antispasmodic agent trospium chloride (TCl) to form solvates was investigated by applying conventional solvate screening methods on 20 solvents. According to the solubility of TCl, different approaches were considered (slow evaporation, slurrying and anti-solvent addition). Five solvates, with the solvents methanol, acetonitrile, propionitrile, N,N-dimethylformamide, nitromethane and dihydrate, were identified and characterized by various analytical techniques. Moreover, a solvate with isopropyl alcohol and TCl sesquihydrate was prepared circumstantially outside the systematic screening. The structures of all the solvates were determined by single crystal X-ray diffraction. The reproducible forms were further characterized by powder X-ray diffraction and desolvation behaviour was observed by thermoanalytical (TGA/DSC) methods. Structural features of novel solvates and of previously described polymorphs and cocrystals of TCl were compared, presented by a tree diagram which classifies the structures according to their molecular packing.

Characteristic features of the positron binding structure of some nitrile (-CN functional group) species such as acetonitrile, cyanoacetylene, acrylonitrile, and propionitrile are discussed with the configuration interaction scheme of multi-component molecular orbital calculations. This method can take the electron-positron correlation contribution into account through single electronic-single positronic excitation configurations. Our PA value of acetonitrile with the electronic 6-31++G(2df,2pd) and positronic [15s15p3d2f1g] basis set is calculated as 4.96 mhartree, which agrees to within 25% with the recent experimental value of 6.6 mhartree by Danielson et al. [Phys. Rev. Lett., 2010, 104, 233201]. Our PA values of acrylonitrile and propionitrile (5.70 and 6.04 mhartree) are the largest among these species, which is consistent with the relatively large dipole moments of the latter two systems.

The quenching of zinc tetraphenylporphine by oxygen and 1,4-benzoquinone was studied using laser-induced optoacoustic spectroscopy in a homologous series of aprotic nitrile solvents consisting of acetonitrile, propionitrile, butyronitrile, and valeronitrile. An inverse correlation exists between the oxygen quenching efficiency of triplet state zinc tetraphenylporphine and the efficiency of singlet oxygen formation, against solvent polarity, in agreement with the accepted involvement of a charge transfer complex during the quenching process. No structural volume change was observed for the triplet state formation of zinc tetraphenylporphine using the nitrile variation method, whereas electron transfer between zinc tetraphenylporphine and 1,4-benzoquinone resulted in a volume contraction in the four nitrile solvents used. Specific solute–solvent interaction, in addition to electrostriction, is needed to fully understand the relatively large and solvent dependent structural volume change observed in the longer chain nitriles. This is due to the varying interaction strength between the electron-pair donor nitriles and the ZnTPP cation as one moves across the solvent series. The free energy of the electron transfer was, however, very similar within the solvent series. The effect of a specific solute–solvent interaction on the rate of electron transfer is unclear at the moment since the latter is found to be limited by the solvent relaxation time, which is much shorter than the time window of the experiments.

The iron(II) complex of 2,4-bis(2-pyridylmethylimino)pentane (L1), trans-[FeL1(MeCN)2][ClO4]2·MeCN, was prepared by a template reaction and isolated as pale red crystals. An acetonitrile solution of the complex exhibited a crossover from a low- to a high-spin form above 20 °C. With this complex as precursor, a series of iron(II) complexes with novel pentadentate ligands, 3-(1-alkyl (or aryl)-methyl)-1-imino-2,4-bis(2-pyridylmethylimine) (L2), was prepared using various nitriles such as propionitrile, isobutyronitrile, benzyl cyanide, benzonitrile, 4-fluoro-, 3,4-difluoro-, and pentafluoro-benzonitrile, as well as acetonitrile, as solvents. On formation of L2, the co-ordination mode of the L1 part of the parent compound was converted from trans into cis-β with concomitant C–C bond formation between the central carbon atom of L1 and the carbon atom of the various nitriles. The isolated triimine part in the pentadentate ligands occupies one of the trigonal faces of the distorted octahedron. The resulting complex undergoes rapid intramolecular isomerization at or above room temperature. The crystal structures of the precursor and of three new iron(II) complexes with pentadentate ligands have been determined.

Acid–base interactions were investigated by mass spectrometry of clusters isolated from solutions containing a carboxylic acid (propionic, butyric or hexanoic acid), an aromatic base (pyridine or pyrazine) and a solvent (water, acetonitrile or propionitrile). In water, self-aggregation of the carboxylic acid molecules due to hydrophobic interaction to form carboxylic acid clusters, such as (butyric acid)n, was prominent, and acid–base interaction proceeded between the carboxylic acid clusters and the basic molecules. In acetonitrile, the acid–base interaction was sensitive to the relative strength of the base. When pyridine (relatively strong base) was used as a base, clustering proceeded through the formation of a polarized acid–base complex, (acid)δ-(base)δ+. However, when pyrazine (relatively weak base) was used as a base, self-aggregation of the acid molecules became favorable. In propionitrile, such clusters were not observed because each molecule was separated by individual solvation. This solvent effect is related to the solvation structure, which determines the balance between the self-aggregation of the acid molecules and the formation of the polarized acid–base complex. It has also been demonstrated that the balance of the above intermolecular interactions is also dependent on the size of the alkyl group of the carboxylic acid. The results of the mass spectrometry partially show the microscopic view for the effect of solvent, pKa and the size of the alkyl group on the acid–base interaction in solution.

Ligand exchange at square-planar [Pd(MeCN)4]2+ and [Pd(EtCN)4]2+ has been studied by 1H NMR line broadening and at [Pt(MeCN)4]2+ and [Pt(EtCN)4]2+ by isotopic labelling using 1H NMR spectroscopy in deuteriated nitromethane. Exchange takes place via two-term rate laws Rex/4 = (k1 + k2[RCN])cM with well defined k1 paths. Rate constants per co-ordination site k1298/s–1, k2298/kg mol–1 s–1 are 6.9 ± 1.6, 34 ± 3; 0.59 ± 0.12, 34 ± 3; 10.7 ± 1.8, 35 ± 4; (5.1 ± 2.3) × 10–6, (2.8 ± 0.2) × 10–5 and (5.5 ± 1.0) × 10–6, (3.3 ± 0.2) × 10–5 for [Pd(MeCN)4][CF3SO3]2, [Pd(MeCN)4][BF4]2, [Pd(EtCN)4][CF3SO3]2, [Pt(MeCN)4][CF3SO3]2 and [Pt(EtCN)4][CF3SO3]2, respectively. For [Pd(MeCN)4]2+ the k1 path is much larger for triflate than for tetrafluoroborate as counter ion. Changing the tetrafluoroborate concentration has no effect on the exchange rate of acetonitrile at [Pd(MeCN)4]2+. In this case the k1 path is ascribed to an attack by solvent at the metal centre. For triflate saturation kinetics is observed. This can be rationalized in terms of ion-pair formation followed by reversible intramolecular exchange of nitrile for triflate within the ion pair, with an equilibrium constant Kip300 = 8 ± 2 kg mol–1 and a rate constant k300 = 12.5 ± 1.3 s–1. All activation entropies are negative, indicating associative activation. A new, simple one-step synthesis of the substrate complexes as their triflate salts, using [M(acac)2] (acac = acetylacetonate) as starting material, and of [Pd(MeCN)4][BF4]2 using palladium(II) acetate, is described.

The reaction of the tetrametallic molecular loop [(CH3CN)6Mo2(OOC-C4H6-COO)]2[BF4]4 (1) (1 equiv.) with 2 equiv. of bis(diphenylphosphino)amine (dppa), 1,2-bis(diphenylphosphino)ethane (dppe) and bis(diphenylphosphino)methane (dppm) in propionitrile leads to the formation of the still tetrametallic complexes [(CH3CH2CN)4(X)Mo2(OOC-C4H6-COO)]2[BF4]4 (X = dppa (2), dppe (3), dppm (4)), also displaying a loop structure. All three complexes are characterized by NMR spectroscopy ((1)H, (11)B, (13)C{(1)H}, (19)F, (31)P{(1)H}), IR spectroscopy, elemental analysis, TG-MS measurements and UV-vis spectroscopy, compounds 2 and 3 additionally by X-ray single crystal diffraction.

Solvent effects on acid–base interactions between phenol and pyridine have been observed via mass spectrometry of solutions containing phenol, pyridine and water, alcohol and nitrile solvents. In the solvents having sufficiently long alkyl chains to solvate phenol and pyridine, such as propan-1-ol and propionitrile, the phenol–pyridine interaction was limited to the inter-unimolecular interactions. However, in the solvents having short alkyl chains such as methanol and acetonitrile, and in water, clustering between phenol and pyridine was observed as a result of inter-cluster interactions. The phenol molecules also formed clusters in methanol and acetonitrile, but not in propan-1-ol or propiontrile. This indicates that the observed clusters are controlled by the solvation structure depending on the solvent alkyl-chain length.

The solvation of copper(I) in mixed solvent systems containing acetonitrile or benzonitrile and the co-solvents propionitrile, butyronitrile, valeronitrile, as well as trimethyl-, triethyl- and tributyl-phosphite has been examined by 63Cu NMR and also, in the case of the phosphites, by 31P NMR. The concentration dependence and the variation of the chemical shift of the silver-109 signal with solvent composition have been studied in solutions of silver trifluoroacetate (AgO2CCF3).

Treatment of a pentasubstituted bromopyrrole with N-bromosuccinimide resulted in a novel oxidative rearrangement involving insertion of oxygen, debromination and migration of an isopropyl group to give 3-[2-(4-fluorophenyl)-1,5-dihydro-2-hydroxy-4-isopropyl-5-oxo-3-(4-pyridyl)-1H-pyrrol-1-yl] propionitrile, an X-ray crystallographic structural determination of which is described.

Recently, cobalt redox electrolyte mediators have emerged as a promising alternative to the commonly used iodide/triiodide redox shuttle in dye-sensitized solar cells (DSCs). Here, we report the successful use of a new quasi-liquid, polymer-based electrolyte containing the Co(3+)/Co(2+) redox mediator in 3-methoxy propionitrile solvent in order to overcome the limitations of high cell resistance, low diffusion coefficient and rapid recombination losses. The performance of the solar cells containing the polymer based electrolytes increased by a factor of 1.2 with respect to an analogous electrolyte without the polymer. The performances of the fabricated DSCs have been investigated in detail by photovoltaic, transient electron measurements, EIS, Raman and UV-vis spectroscopy. This approach offers an effective way to make high-performance and long-lasting DSCs.

In this study, a potentiometric sensor, based on the natural mineral pyrite as an electroactive material, is used for a simple and fast determination of different halide and thiocyanate ions such as hydroxylammonium chloride, potassium iodide, tetrabutylammonium bromide, and ammonium thiocyanate, in addition to titrations of some biologically important systems (choline chloride, cetyltrimethylammonium bromide), which include verapamil hydrochloride as well as its determination in pharmaceutical formulation. Verapamil is a calcium channel blocker used in the management of angina, arrhythmia and hypertension. Halide and thiocyanate ions can be determined by a precipitation titration with silver nitrate as the titrant in non-aqueous solutions, and the end-point can be evaluated by a potentiometric method, in which a pyrite electrode is used as the indicator electrode. The sensor shows a stable, near Nernstian response, over the concentration range 1.0 × 10−4–1.0 × 10−1 M of standard silver ion solutions at 25 °C with a cationic slope of 63.6 and 59.3 mV per decade in acetonitrile and propionitrile, respectively. The wide linear range, fast response time (∼15 s), reproducibility, a long service life without considerable divergence in potentials are characteristics of the proposed sensor for precipitation determination in acetonitrile and propionitrile. Potentiometric determination of 10–80 mg of the investigated substances shows an average recovery of 98.7% and a mean standard deviation of 0.6%.

The low temperature adsorption of CO and the room temperature adsorption of propionitrile and ortho-toluonitrile on LiMOR, NaMOR, KMOR and CsMOR zeolites have been investigated by FT-IR spectroscopy. Two different CO species, both most probably located in the main channels coordinated on Na ions at IV and VI sites, have been observed. They are associated to a shift of the CO stretching to higher frequencies, as usual. However, together, more strongly bonded species associated to a slight shift of the CO stretching to a lower frequency are also observed. Similar species, with the CN stretching shifted upwards (weaker adsorption) and with the CN stretching shifted downwards (stronger adsorption) are also observed in the case of the interaction of propionitrile (PrN), a molecule that should enter the main channels, and in the case of the interaction of ortho-toluonitrile (o-TN), whose access to the main channels should be highly hindered. The data show that the species characterized by a stronger adsorption but a lower stretching frequency may form both in the main channels and at the external surface. Their formation is easier with the larger cations. These species are identified as "multiply bonded", possibly to two cations. The evidence for this new interaction, stronger than the usual one site-one molecule species, may change considerably the view of the adsorption chemistry of cationic zeolites, from localized simple sites to cooperative complex interactions.

The carbanion of 2-phenylpropionitrile adds to nitrobenzene in the p-position in liquid ammonia to give the relative stable σH-adduct which is oxidised with KMnO4 to 2-phenyl-2-(4-nitrophenyl)propionitrile; the relationships of rates of various reactions in these systems are estimated.

Two one-dimensional hexaaza macrocyclic coordination polymers with the formulae [CuL]n(ClO4)2n and [NiL]n(ClO4)2n, where L = 3,10-bis(2-propionitrilo)-1,3,5,8,10,12-hexaazacyclotetradecane, have been synthesized, and characterized by elemental analyses and single-crystal X-ray analyses. In both polymers, each Cu(II) or Ni(II) ion is six-coordinated with four nitrogen atoms of the macrocycle and two nitrogen atoms of the propionitrile pendant groups from neighboring macrocycles. In [CuL]n(ClO4)2n, the coordination geometry of the copper atom is an elongated octahedron with four macrocyclic nitrogen atoms in the equatorial plane (Cu–N = 2.022(3) A) and two propionitrile nitrogen atoms in the axial positions (Cu–N = 2.513(3) A).

Formation of a nitrile ylide (NY) by addition of a singlet carbene to a nitrile compound was studied by laser flash photolysis (LFP) of (biphenyl-4-yl)chlorodiazirine (BCD) in the presence of nitrile compounds. Although the generated (biphenyl-4-yl)chlorocarbene (BCC) forms a NY by addition to a nitrile compound in an equilibrium reaction, the absorption spectrum of the NY can be measured only in the LFP of BCD in the presence of 2,4,6-trimethoxybenzonitrile. The equilibrium constants for the NY formation in the addition of BCC to propiononitrile or pivalonitrile were determined to be 0.45 and 0.37 M–1 at 295 K, respectively. The reactivity of NY towards olefins seems to be substantially lower than those of BCC. The reaction of BCC with 2,3-dimethylbut-2-ene was carried out in 2,2,4-trimethylpentane and propionitrile in the temperature range of ca. 170 to 300 K. In both solvents, the rate constants increased with decreasing temperature and the maximum value appeared at around 210 K. Using the difference in the rate constants, the free energy difference for the equilibrium constant was also estimated to be ca. 4.2 kJ mol–1.

Structural phase transitions have been observed using IR–VIS sum frequency generation (SFG) at the air/acetonitrile–water and the air/propionitrile–water interfaces but not at the air/butyronitrile–water interface. The phase transitions were detected by abrupt changes in the CN vibrational frequency and in the orientation of the CN chromophore as the interface nitrile density was varied. A model based on the orientational effects of hydrogen bonding and solvation of the CN group by water molecules competing with the density and orientationally dependent dipole–dipole repulsions among the CN chromophores is used to explain the results.

When treated with thallium(III) acetate in acetic acid or acetonitrile, flavanones undergo facile dehydrogenation to afford flavones whereas, upon treatment with thallium(III) toluene-p-sulfonate or thallium(III) nitrate in propionitrile or acetonitrile, respectively, they undergo oxidative 2,3-aryl migration to give isoflavones in high yield.

Irradiation of 1-aryl-2,2-dicyanoethenes and tetraalkylstannanes in propionitrile in the presence of phenanthrene afforded regioselectively 1-alkyl-1-aryl-2,2-dicyanoethanes in good yields.

The interaction of trans-Cr(N2)2(dmpe)2[dmpe = 1,2-bis(dimethylphosphino)ethane] with hydrogen chloride gives the eight-co-ordinate chromium(IV) species CrH2Cl2(dmpe)2 whereas CF3CO2H gives trans-Cr(O2CCF3)2(dmpe)2. Protonation by CF3SO3H of trans-CrL2(dmpe)2(L = N2 or C2H4) in MeCN or EtCN gives the chromium(II) octahedral nitrite species trans-[Cr(NCR)2(dmpe)2]2+(R = Me or Et). The electron spin resonance spectra of the latter are attributed to trace impurities of a chromium(I) nitrite species; the main quintet is typical of CrI with four equivalent phosphorus ligands but hyperfine splitting is ascribed to interaction of CH3 groups of MeCN and CH2 groups of EtCN with the 17-electron chromium(I) atom. The interaction of trans-Cr(N2)2(dmpe)2, trans-CrCl2(dmpe)2, or CrH4(dmpe)2 with CH3I or I2 in methanol leads to compounds of general formula trans-[CrIIIX2(dmpe)2]X′(X = Cl or I, X′= I or BPh4). The interaction of cis-Cr(CO)2(dmpe)2 with CF3SO3H followed by treatment with NaBPh4 in MeOH leads to the seven-co-ordinate [CrH(CO)2(dmpe)2]BPh4, while treatment of the dicarbonyl with one equivalent of AgCF3SO3 leads to trans-[Cr(CO)2(dmpe)2]BPh4. X-Ray structures of the following compounds have been determined: trans-Cr(O2CCF3)2(dmpe)2, trans-[Cr(NCR)2(dmpe)2][CF3SO3]2(R = Me or Et), trans-[CrCl2(dmpe)2]BPh4·CH2Cl2, [CrH(CO)2(dmpe)2]BPh4, and trans-[Cr(CO)2(dmpe)2]BPh4.

Optical emission was observed from several nitriles following 58.4 nm excitation. The emission from pentafluorobenzonitrile was assigned to the parent radical cation and is compared with emission from other fluorinated aromatic cations. CN emission from acetonitrile was shown by lack of ion–photon coincidence to come from a neutral-product channel and is similar to that observed at longer excitation wavelengths. Propionitrile and allyl cyanide showed weaker CN emission, while several other nitriles gave no visible-region light emission.

For determining small amounts of water in non-aqueous solvents (acetonitrile, propionitrile, dimethylformamide and tetrahydrofuran) IR and near-IR spectrometry were applied. In order to prevent overlapping of the observed water band with that of the solvent, either one of the fundamental vibrations (v1 or v3 at about 3500 cm–1) was selected or combination vibrations (v1+v2) at 5200 cm–1. This method is rapid and convenient, especially in laboratories that are not equipped with a single-purpose analytical titrator according to Karl Fischer, or where water is not often determined. The detection limit is about 20 p.p.m. of water, i.e., 10–3 mol l–1. Further uses of the method were verified experimentally and are discussed.

Infrared spectra of silica immersed in liquid mixtures of 2,2,4-trimethylpentane + propionitrile, toluene + propionitrile and 2,2,4-trimethylpentane + toluene + propionitrile have been recorded using an infrared cell of novel design. Absorbance data, taken from the spectra, enabled the fractions of isolated surface silanol groups perturbed by each component of the liquid mixtures to be evaluated. The results illustrate the applicability of infrared spectroscopy to the study of adsorption from three-component liquid mixtures.

Protonation of the rhenium polyhydride complexes [ReH7(PPh3)2], [ReH5(PPh3)2L][L = pyridine (py), NH2(C6H11), or NH2But], or [ReH4I(PPh3)3] with HBF4·Et2O in acetonitrile or propionitrile leads to the seven-co-ordinate complexes [ReH (NCR)3(PPh3)2L][BF4]2[R = Me or Et; L = RCN, PPh3, py, NH2(C6H11), or NH2But]. Their 1H and 31P-{1H} n.m.r. spectral properties are consistent with pentagonal-bipyramidal or face-capped octahedral geometries in solution. These complexes show a reversible one-electron oxidation in the potential range +1.0 to +1.6 V (vs. Ag–AgCl) in 0.1 mol dm–3 NBu4PF6–CH2Cl2, and an irreversible reduction below –1.4 V. The substitution chemistry of [ReH(NCR)4(PPh3)2][BF4]2 has been investigated and the mixed-phosphine complexes [ReH(NCR)3(PPh3)(dppe)][BF4]2(R = Me or Et; dppe = Ph2PCH2CH2PPh2) isolated as the initial reaction products. These species have been characterized by i.r. and n.m.r. spectroscopy and by cyclic voltammetry. Further reaction with dppe leads to reductive substitution and the formation of [Re(NCR)2(dppe)2] BF4.

The pyrolysis of propionitrile has been studied at seven temperatures over the range 789–850 K and pressures between 10 and 100 Torr.; Under these conditions the principal reaction products which are formed by essentially homogeneous processes are hydrogen, hydrogen cyanide, methane, ethane, ethene, acetonitrile and acrylonitrile. For short reaction times (< 3% conversion) the products are formed at rates which do not vary noticeably with reaction time.A free radical chain mechanism has been proposed which accounts for all the above products. The chain initiating step is the reaction C2H5CH →·CH3+·CH2CN. (1). Measurements of the rate of formation of methane in the subsequent reaction ·CH3+ C2H5CN → CH4+ CH3ĊHCN (2) yield the rate expression log10(k1/s–1)=(15.5 ± 0.3)–(78 700 ± 950)/θ where θ= 2.303 RT/cal mol–1. The activation energy leads to D(H3C—CH2CN)= 80.4 ± 1 kcal mol–1 and a resonance energy of 5.4 ± 1.4 kcal mol–1 for the cyanomethyl radical.

The electronic absorption spectra of acetonitrile, propionitrile and butyronitrile have been determined using the method of electron impact spectroscopy. Spectra are presented which were obtained at 70 eV impact energy and zero scattering angle. Results obtained at 90° scattering angle at lower impact energies are briefly mentioned. The spectra are interpreted in terms of excitations to valence excited states and Rydberg states. Three Rydberg series each are found for acetonitrile and propionitrile. A previously unreported absorption occurring at about 6 eV in each of the zero scattering angle spectra is tentatively assigned as a triplet excitation and one at about 8 eV in the 90° scattering angle spectra is assigned as a triplet excitation.

The adsorption of propionitrile on polarized Hg electrodes has been studied from 0.25 mol dm–3 NaF aqueous solutions by means of both electrocapillary and capacity curves. The results show that the adsorption isotherms are apparently congruent with respect to both charge and potential on the negative side of the maximum in adsorption. In this region, a Frumkin isotherm is obeyed with saturation coverage Γs= 5.9 × 10–10 mol cm–2, corresponding to a projected area A= 28 A2 per molecule, and an interaction parameter corresponding to intermolecular attraction. On the positive side of the maximum in adsorption, the isotherms are congruent with respect to neither of the two electrical variables. The adsorption may be described by a Frumkin isotherm either with constant Γs and interaction parameter a changing quadratically with charge, or with constant a and Γs linearly decreasing with charge on the metal, although at the more positive charges the latter description appears more adequate for describing the experimental results.Results are discussed in terms of polarization of the CN group giving rise to a net positive charge on the propionitrile molecule. This generates repulsion between particles depending on charge and therefore non-congruence. Some implications about the physical meaning of the parameters in the isotherms are discussed. A model for the adsorbed layer is proposed.

Infrared spectra have been recorded of silica which had been evacuated at 423 K and subsequently immersed in solutions of propionitrile in toluene, 2,2,4-trimethylpentane and toluene + 2,2,4-trimethylpentane mixtures. The adsorption process involved the formation of hydrogen bonds between surface hydroxyl groups and the cyano groups of propionitrile molecules. The adsorption of propionitrile on silica was impeded by strong lateral interactions between adjacent surface silanol groups. Only isolated hydroxyl groups and weakly interacting hydroxyl groups acted as adsorption sites. Increasing strength of interaction between the predominant (hydrocarbon) components of the liquid phase and surface silanol groups decreased the surface concentration of propionitrile molecules for a particular equilibrium concentration in solution.

After light excitation, 2-aminophenyl phenylsulphone has been found to fluoresce strongly in polar solvents (ϕf= 0.20 in aerated propionitrile solution, room temperature). The dependence of the absorption and emission spectra on solvent polarity has shown that the excited state involved in the lowest-energy absorption which is responsible for the emission is of charge-transfer nature with moderate charge delocalization (µ≈ 6.5 D from emission measurements). The temperature dependence of the emission lifetime and emission spectrum has been obtained for the temperature range 293–90 K in propionitrile-butyronitrile (4 : 5 v/v) solution. While the emission intensity increases monotonically from room temperature to 90 K, ϕf= 0.27 to 0.54, respectively, the lifetime increases from room temperature (τf= 6.5 ns) to 150 K (τf= 10.6 ns), but decreases on further lowering the temperature (τf= 8.3 ns at 90 K). This complicated behaviour is explained in terms of solute–solvent polar interactions and by taking into account the freezing of the solvent for T < 150 K.

Dielectric constants and losses have been measured at wavelengths of 3 × 104, 10.0, 3.22, 1.96, and 1.25 cm at 30°C for pure acetonitrile, pure propionitrile, five mixtures of acetonitrile and benzonitrile and three mixtures of propionitrile and benzonitrile. A single relaxation time of 3.3 × 10–12 s has been obtained for pure acetonitrile, whereas the dielectric data of pure propionitrile indicate an unsymmetrical distribution of relaxation times in good agreement with the Davidson-Cole representation. The dielectric data of the binary mixtures of acetonitrile and benzonitrile have been analyzed in terms of two partly superimposed Deby e regions, whereas that of propionitrile and benzonitrile have been interpreted in terms of three partly overlapping Debye regions.

The vibrational spectra of the following species under a variety of conditions are reported and discussed: MCl4 and MCl4,SbCl5(M = S, Se, Te); TeCl3,AsF6; TeCl4,PCl5; TeCl4,AlCl3; SCl2; S2Cl2; MCl62–(M = Se, Te). Molecular-weight data are given for benzene solutions of TeCl4 and TeCl4,AlCl3. The ultraviolet spectra of solutions of TeCl62– and TeCl4 in propionitrile show the formation of a new species at a mole ratio of 1 : 1. This new species is apparently the TeCl5– ion. Some data are reported for the compounds SeCl4,py2 and TeCl4,py2(py = pyridine).

The o-, m-, and p-nitrobenzylidene derivatives of acetylacetone react with potassium cyanide to yield products of different types; respectively 3-acetyl-2-methylquinoline-4-carboxamide 1-oxide, the simple adduct, and 3-acetyl-5-amino-2-methyl-4-(4-nitrophenyl)furan. Various o-nitrobenzylidene compounds are attacked by cyanide ion with concomitant cyclisation to give derivatives of quinoline 1-oxide and/or 1-hydroxyindole. Easy hydrolysis of the introduced cyano-group to an amide function often occurs in the quinolinic but not in the indolic cyclisation. Related base-catalysed cyclisations are described for 2,3-bis-(2-nitrophenyl)propionitrile and 3,4-dibenzoyl-2-(2-nitrophenyl)butyronitrile. The unusual stability of the aldol which is obtained from o-nitrobenzaldehyde and cyclohexanone and the evidence of interaction between neighbouring ketonic and carbamoyl groups and ketonic and cyano-groups are noted.