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The gas-phase reactions of OH- and SH- with NCCH2CH2Cl have been studied with ab initio methods using the 6-31+G* basis sets. The electron correlation effect was accounted for at the MP2 level of theory. Both the SN2 and E2(anti) reactions are exothermic and have negative activation barriers when Cl- is the leaving group. Overall, E2 is preferred to SN2, and E2(anti) is favored over E2(gauche) for both OH- and SH-, indicating the preference of an antiperiplanar transition state in the gas phase. Since SH- is a weaker gas-phase nucleophile than OH-, the transition state occurs later on the reaction coordinate. The results of this work are consistent with those of gas-phase experimental studies which indicated that first-row nucleophiles undergo both SN2 and E2 reactions, whereas second-row nucleophiles have lower abilities to induce elimination reactions. Substitution of a CN group for a β-hydrogen of CH3CH2Cl to NCCH2CH2Cl is found to enhance both the SN2 and E2 reactivities and makes the β-H-elimination ...

A number of bi-metallic Cr III cyanides exhibiting high magnetic ordering temperatures have recently been reported. Here, first-principles theory based on the unrestricted Hartree-Fock approximation, has been applied to the idealised compounds KM II [Cr III (CN) 6 ] (M II  V, Mn, Ni) and Cr III [Cr III (CN) 6 ] in order to gain insight into the magnetic interactions. The computed magnetic ground state and ordering energies are consistent with recent experimental observations of the parent materials. It is found that the metal-ligand interactions are ionic in nature. The large magnetic coupling between the metal d-orbitals can be understood in terms of a superexchange model in which the orthogonality constraint is relaxed through delocalisation of the d-orbitals and polarisation of the CN group. The contribution of covalent interactions to the magnetic coupling is small.

New derivatives of thiophene-fused DCNQI and their CuI complexes have been prepared. Among those, β, β″-dimethyl derivative (2) afforded a single crystal of complex (2)(CuI)2 suited for an X-ray analysis and its crystal structure has been determined. The structure is built up of the zigzag ladder of CuI polymer. Bidentate ligand molecules of 2 bridge the CuI ladders by coordinating the CN group to Cu of the ladder. The acceptor π-plane is arranged face-to-face with interplanar distance of 3.56 A. The room temperature conductivity of (2)(CuI)2 was 7.6 × 10−3 Scm−1 with semiconductive behavior in the temperature dependent conductivity.

The structure of the new Cu-Zn bimetallic compound, triamminezinc(II) bis[dicyanocuprate(I)] is built up from infinite –Cu-AA-Cu-AA– (where AA represents a disordered CN group) helical chains with 21 symmetry. Terminal cyano groups and –CN-Zn(NH3)3 groups are bonded alternately to the Cu atoms of the chains. Both crystallographically independent CuI atoms are trigonally coordinated by three cyano groups. The ZnII atom is tetrahedrally coordinated by three ammonia molecules and one nitrogen-bonded cyano group. The intra- and interchain CN⋯HN hydrogen bonds contribute to the stabilization of the structure.

Ab initio electronic structure calculations have been performed to characterize the charge-transfer process in benzonitrile, 4-aminobenzonitrile and 4-dimethylaminobenzonitrile. The HF, CIS, CASSCF and CASPT2 methods have been employed. Geometry optimization of the charge-transfer state predicts a planar configuration with bent CN group. The results suggest that bending of the cyano group rather than twisting of the amino group is the intramolecular motion which is responsible for the stabilization of the charge-transfer state in aminobenzonitriles.

Crystal structures and magnetic properties of the layered pervoskite compounds, (p-X-C6H4NH3 +)2CuCl4 2-with X=CN (1), Cl(2), and NO2 (3), were studied. The compound 1 crystallizes in the triclinic P 1 space group. The structure consists of a CuCl layer and an organic bilayer in which the molecular axis of the cyanoanilinium is nearly perpendicular to the inorganic layer. At the middle of the organic bilayer, there is a layer of the CN group, in which the CN groups are arranged to cancel their electric dipoles. The compound 2 has a similar structure to that of 1. The crystal of 3 belongs to the orthorhombic Pbca space group, in which the structure also consists of an inorganic layer and an organic bilayer. The bilayer is formed by short contacts between the NO2 groups, which appear to incline the molecular axis of the nitroanilinium with respect to the normal to the CuCl layer. AC and DC magnetic susceptibility measurements were carried out on the three salts. Their behavior can be understood wit...

The reaction of 3-cyanopyridine-2(1 H)-thiones with BuLi in ether was studied. It was found that the metallation proceeds initially at the sulfur atom. The resulting lithium salts add a second equivalent of n-butyllithium at the CN group. The hydrolysis of the dilithium derivatives leads to 3 pentanoylpyridine-2(IH)-thiones.

Reaction of 1,3-dicyanotetrafluorobenzene with 2 equiv of (trimethylsilyl)iminophosphoranes gave the disubstituted derivatives 4,6-(CN)2C6F2-1,3-AB: 1, A = B = (NPPh3); 2, A = B = (NPPh2Me); and 3, A = (NPPh3), B = (NPPh2Me). Monosubstituted compounds of the type 2,4-(CN)2C6F3-1-A; notably 4, A = (NPPh3), and 5, A = (NPPh2Me), were readily obtained by reaction of 1 molar equiv of the silylated iminophosphorane with the cyanofluoro aromatic. Substitution of the fluorine para to the CN group(s) occurs in all cases. Reactions of 1,2- and 1,4-dicyanotetrafluorobenzene with (trimethylsilyl)iminophosphoranes gave only monosubstituted derivatives 3,4-(CN)2C6F3-1-A (6, A = (NPPh3), and 7, A = (NPPh2Me)) and 2,5-(CN)2C6F3-1-A (8, A = (NPPh3), and 9, A = (NPPh2Me)), respectively, as the result of electronic deactivation of the second substitutional point. 1, 4,6-(CN)2C6F2-1,3-(NPPh3), 2, 4,6-(CN)2C6F2-1,3-(NPPh2Me)2, and 3, 4,6-(CN)2C6F2-1-(NPPh3)-3-(NPPh2Me) have been structurally characterized. For 1 (at 21 °C),...

The title inclusion compound [{NH2(CH2CH2)2NCH2CH2NH2}2H][Cu4(CN)7] was obtained as single crystals from an aqueous solution containing CuCN, KCN, andN-(2-aminoethyl)piperazine. It crystallizes in the monoclinic space groupP2/n,a = 12.3829(9),b = 8.5970(9),c = 12.6633(7) A, β = 109.984(5)°,z = 2,R = 0.035 for 2921 independent reflections. The inclusion structure is composed of the hydrogen-bonded dimeric onium guest [{NH2(CH2CH2)2NCH2CH2NH2}2H]3+ and the negatively-charged three-dimensional host [CU4(CN)7]3− in which the CN-bridged framework Cu(I) atoms are all tetrahedral. A polyacene-like one-dimensional array of hexagons cornered by Cu(I) atoms and edged by -CN- linkages is arrayed in parallel to theb axis and stacked approximately along the c axis. The Cu(I) corner shared in the one-dimensional array extends an N-coordinate CN group along the c axis to a pair of unshared Cu(I) corners for which the C end behaves as a bifurcated ligand to build up the three-dimensional host structure. The cavity is composed of two networks of the hexagons at the top and bottom and pillared by six >CN- groups and accommodates a dimeric guest ofN-(2-aminoethyl)piperazinium cations protonated at each 4-N with the cations being hydrogen-bonded to each other through the 2-NH2 groups sharing another H+.

Organic Chemistry The toxicity of hydrogen cyanide (HCN) is well known. Nonetheless, numerous useful nitrile compounds contain CN groups, and the reaction of HCN with C=C double bonds is often used. Fang et al. now report an alternative to shuttle a CN group from one molecule to another that relies on Ni and Al catalysts (see the Perspective by Schmalz). This transfer procedure circumvents the need for HCN and can be applied to complex substrates using a simple sacrificial nitrile donor. It can also be run “in reverse” to derive an olefin of interest from a nitrile precursor. Science , this issue p. [832][1]; see also p. [817][2] [1]: /lookup/doi/10.1126/science.aae0427 [2]: /lookup/doi/10.1126/science.aaf2215

Two series of new compounds with sterically shielded, sp2-hybridized C-α atoms are prepared from bromo(chloro)-2,6-diisopropylbenzene. The α-(2,6-diisopropylphenyl) substituent common to all of them is used as an NMR-spectroscopic indicator for the ease of aryl-α single-bond rotation. The corresponding ΔG≠ values are >23.8 kcal/mol with methyl or bromine as additional α substituents at a CC bond, but 23.3 kcal/mol, and ΔG≠ ≈ 31.5 kcal/mol for the (Z)-hydrazone. Comparisons of these data with reaction conditions show that chemical transformations are not seriously impeded unless they depend on reagent attack at a π face of the C-α atom in a CC or CN group which rotates slowly about the bond to 2,6-diisopropylphenyl.

The valence isomeric equilibria between cycloheptatriene and norcaradiene and, as well, their substituted derivatives at position 7 containing strong electron withdrawing groups (7-cyano, 7,7-dicyano and 7,7-difluoro substituted) were investigated computationally using ab initio methods and charge density topological analysis at the 6-31G ∗ , 6-31G ∗* and MP2/6-31G ∗* levels of theory. The calculated relevant cross sections of the potential energy surface shows that the 7,7-dicyanonorcaradiene, in which the CN group acts as a σ- and π-acceptor, behaves as a stable neutral homoaromatic compound. As a comparison, the destabilized 7,7-difluoronorcaradiene, in which fluorine substituents act as a σ-acceptor and a π-donor, was studied also.

Nucleophilic attack towards the C atom of the CN group in CH3CN, NH2CN and FCN is analyzed on the basis of the laplacian of the molecular charge density ϱ(r) obtained from ab initio calculations. The relative reactivity of the C atom towards a nucleophilic attack, predicted by the values of the laplacian of ϱ(r) at the (3, +1) critical points of the valence shell, is in accordance with experiment. The connection between the electron-withdrawing ability of the substituent in aliphatic nitrites and nucleophilic attack toward the C atom was also obtained.

Excess volumes, VE, by means of a vibrating-tube densimeter, and Vapor-Liquid equilibria, by head-space gas-chromatographic analysis of the equilibrated vapour phase directly withdrawn from equilibration apparatus, of binary mixtures containing n-alkanenitriles with n-alkanes or cyclohexane, were determined at 298.15 K. Measurements of the test mixtures, ethanol + cyclohexane were also made. Excess molar Gibbs free energies, GE, for the examined mixtures were obtained by a least - squares treatment of the equilibrium x, y results. The VEand GE values are positive for all the systems. The steric effect exerted by the alkyl groups adjacent to the CN group results in a regular decrease of the GE with increasing the number of alkyl groups in the alkanenitrile.

The slightly yellow-coloured title complex, [Zn(C18H16N4O4)(H2O)]n, crystallizes with one molecule in the asymmetric unit. The structure clearly shows themer-η4O,O,N,N-binding mode of theN,N′-bis-(2-cyano-ethylpropenoyl)-1,2-diamidobenzene ligand stabilizing the Zn centre of a distorted octahedral environment. The fifth coordination site in one apical position is held by a coordinating solvent water molecule whereas the complete octahedral coordination sphere is completed by coordination of one N atom from a CN group of a neighbouring molecule, leading to the final polymeric structure consisting of zigzag staggered chains in parallel orientation along thec-axis direction. Between the coordinated water solvent molecule and the N atoms of uncoordinated cyano-groups of neighboured units, two H-bridge bonds are formed. One of these H-bridge bonds is of inter- whereas the other of intra-strand nature, leading to a two-dimensional network parallel to (110) stabilizing the supramolecular structure. Six Zn—O or Zn—N bonds are found with lengths ranging from 2.061 (1) to 2.185 (1) Å and bond angles about the Zn atom are clustered in the ranges 79.83 (4)–104.21 (4) and 167.05 (4)–170.28 (4)°.

The title compound, C24H29NO3, has a phase sequence of crystals–smectic A–nematic–isotropic liquid. The molecular length of the compound is 25.323 (9) A. Intermolecular contacts between two CN groups, between a carbonyl­oxy and a CN group, and between two carbonyl­oxy groups are observed in the crystal state.

Tris(benzo[b]thienyl)methanol (1) forms pseudo-polymorphs of crystalline host–guest compounds enclathrating MeCN in different ratios. These are characterized by the formation of discrete –OH---NC hydrogen bonds. The FTIR spectra show that the 1∶1 crystal is comprised of strong interactions, while the 2∶1 one of weak –OH---NC interactions. The 2∶1 crystal forms an unusual bifurcated hydrogen bonding to the CN group, as revealed by an X-ray crystal analysis. The 1∶1 crystal is transformed to the 2∶1 one at 80 °C by release of half of the guest molecules and reorganization of the hydrogen bonding and is further converted to the guest-free crystal of 1 at 150 °C.

2D IR spectroscopy was used to probe the hydrophobic core structure of the 35-residue Villin headpiece subdomain, HP35, by monitoring the C≡N vibrational stretching band of a cyano substituted phenylalanine (Phe). The presence of two humps in the vibrational frequency distribution in the folded equilibrium state is revealed. They represent two states that exchange more slowly than ca. 10 ps. The two CN stretch mode peak frequencies (and their equilibrium populations) are 2228.7 (44%) and 2234.5 cm(-1) (56%). The two CN modes have different frequency-frequency correlation times of 7.4 ps and 1.6 ps respectively. These results suggest that the population with the higher frequency CN group is partly exposed whereas the other CN mode experiences a hydrophobic like environment.

The isoquinolinones 8 undergo acid-induced rearrangement to yield the isomeric 1,1-dihydro-3-aroylisoindoles 9 in good yield. The reaction involves hydrolysis of the CN bond to afford a putative intermediate amino diketone 10. Cyclization within this is controlled by two factors (i) the stability of the CN group in the starting material and product and (ii) the relative reactivity of the two carbonyl groups.

A new class of second-order nonlinear optical chromophores resulting from the replacement of the most reactive CN group in tricyanovinylthiophene derivatives with aryl units, are designed and synthesized.

A series of asymmetric donor-acceptor substituted salen-type Schiff-bases have been synthesized and their structures, electronic properties and second order nonlinearities were investigated by DFT methods. In order to verify the stable of these Schiff-base derivates, the IR spectrum of these Schiff-base derivates were calculated, the result showed that these compounds are stable. The results of TD-DFT calculation indicate that the derivatives with the electron-donating group (CH3, OCH3 or N(C2H5)2) have a red shift absorption compared to derivatives with the electron-withdrawing group (NO2). The analysis of MOS indicates that the CN group has contribution to the LUMO orbital while the groups of OCH3, N(C2H5)2 and NO2 have contribution to the HOMO orbital. OCH3, N(C2H5)2 as electron rich groups, made the derivates have a larger first static hyperpolarizability. However, the compound (II) with a NO2 substituent, also has a large first static hyperpolarizability. This is probably because of the special transition model, namely the values of two oscillator strength f (fHOMO-1-LUMO=0.405, fHOMO-LUMO=0.321) are almost equal. In order to understand the influence of the energy gap (ΔE) between the HOMO and the LUMO orbitals on the first static hyperpolarizability, we calculated the energy gap (ΔE) of all Schiff-base compounds. The results show that the smaller the HOMO-LUMO energy gap is, the larger the first static hyperpolarizability is.

A stereoselective radical cascade cyclization of polyene 6, containing an α,β-unsaturated cyano group, was employed to control six contiguous chiral centers and to introduce a C-8 angular CN group ...

A series of highly efficient, chemically and thermally stable (>310 °C) nonlinear optical chromophores were prepared through the replacement of the most reactive CN group in tricyanovinylthiophene derivatives with perfluoroaryl units.

The molecular structure of 3a-alkyl-3-cyano-2-oxofuro[2,3-b]indoles 1a–d and 3a-alkyl-3-methoxycarbonyl-2-oxofuro[2,3-b]indoles 2a–c has been determined by 1H NMR spectroscopy, X-ray diffraction and semiempirical (AM1) and abinitio (HF/3-21G* level) quantum chemical calculations. Considering detailed NOE measurements and the anisotropic effects of the C(3) carbonyl ester group, the preferred configurations were determined in solution. In these compounds the thermodynamic preference of the C(3) electron-attracting substituent for the endo or exo face appears to be controlled by the steric demand of the C(3a) alkyl substituent. The structurally folded furoindoles endo-2a–c evidence a repulsive interaction between the sterically crowding CO2Me group and the π system of the benzene ring. An increase in the solvent polarity significantly alters the endo∶exo ratio in favor of the endo isomer. The solid-state structures of 1d and 2a demonstrate that these compounds assume configurations which differ in the spacial orientation of the C(3) substituent, with the CN group in 1d oriented to the endo face and the CO2Me group in 2a to the exo face of the molecule, in agreement with those configurations determined in CD2Cl2 solution and from theoretical calculations.

Cyanoacetyldiazoindol-2-one (3), the condensation product of cyanoacetohydrazide with isatin (1), could be cyclized in acidic medium via its CN group and its enolic OH to give cyanomethyloxadiazole-spiroindoline (4). The presence of the methylcyano side chain could be invested—through oximation, diazotization, or condensation with aldehydes—to form polyfunctional spiroindolines 5, 8–10. Also, a second route for preparing the title compound could be achieved through a nucleophilic attack on position 3 in the isatin derivatives, followed by subsequent ring closure to give 6 and 7. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:207–210, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10020

International audience; Reactions of CuCl 2 with different CN complexes in presence of a neutral ancillary ligand lead to two novel mixed-valence Cu complexes [Cu II (bpy)Cu I (CN) 3 ] n , 1 (bpy=2,2′-bipyridine) and {[Cu II (tn) 2 ][Cu I 4 (CN) 6 ]} n 2 (tn=1,3-diaminopropane). For compound 1, the asymmetric unit involves two Cu ions Cu1 and Cu2 (Cu I and Cu II centres, respectively) which strongly differ in their environments. The Cu1 ion presents a CuC 4 pseudo-tetrahedral geometry, while the Cu2 ion presents a CuN 5 slightly distorted square-pyramidal geometry. The extended structure of 1 is generated by three cyano ligands which differ in their coordination modes. One CN group has a μ 3 coordination mode and bridges two Cu I and one Cu II ion, while the two other CN groups act as μ 2 bridges leading to a sophisticated 3-D structure. As for 1, the asymmetric unit of 2 involves three crystallographically different Cu ions (Cu1A and Cu1B, presumably Cu I centres, and Cu2 presumably Cu II centres). The Cu2 ion presents centrosymmetric CuN 4 coordination environments involving four nitrogen atoms from two bidentate tn ligands; while the Cu1A and Cu1B ions are three coordinated to cyano groups. The structure can be described as formed by 18-membered “[Cu I (CN)] 6 ” planar metallocycles that are connected to their six neighbors to generate 2-D sheets; these sheets stack forming infinite hexagonal channels in which the [Cu(tn) 2 ] 2+ units are located. Magnetic measurements show an unexpected weak ferromagnetic coupling (θ=0.239(1)K) of the Cu II ions through the long and “a priori diamagnetic” –NC–Cu I –CN– bridges in compound 1 and an essentially paramagnetic behavior in compound 2.

The reactions of [Fe 2 {μ-C(CN)SMe 2 }(μ-CO)(CO) 2)(Cp)[in2 ]SO 3 CF 3 (Cp = η-C 5 H 5 ) with alcohols and alkoxides have been investigated. Nucleophilic attack of the oxygen atom on the μ-C carbon with displacement of the Me 2 S molecule was observed in all cases. The resulting μ-cyanoalkoxycarbene derivatives [Fe 2 {μ-C(CN)OR}(μ-CO)(CO) 2 (Cp) 2 ] (R = Me, 2a ; Et, 2b ; i Pr, 2c ; CH 2 Ph, 2d ; CH 2 CHCH 2 , 2e ; CH 2 CH 2 NMe 2 , 2f ; CH 2 CH 2 OH, 2g ; C 6 H 5 , 3a ; C 6 H 4 - o -NO 2 , 3b ) have been characterized spectroscopically. The complex [Fe 2 {μ-C(CN)OCH 2 CHCH 2 }(μ-CO)(CO) 2 (Cp) 2 ] ( 2e ) undergoes a photolytically-promoted intramolecular CO substitution by the olefinic termination to give [Fe Fe{μ-C(CN)OCH 2 CH CH 2 }(μ-CO)(CO)(Cp) 2 ] ( 5 ), which was be subjected to an X-ray diffraction study. Some structural features were as expected, in particular the location of Cp in a cis disposition with respect to the CN group. The molecule is asymmetric as a consequence of the coordination of the allyl in the place of a terminal CO group; the configurations of the four chiral centres are discussed.

The reaction of chiral p -tolylsulfinylmethyl ketones (R-CO-CH 2 -SOTol, RPh, Et and t -Bu) with Et 2 AlCN, yields almost optically pure sulfinyl cyanohydrins (d.e. ≥ 96%). The reaction was quicker in the presence of ZnCl 2 , but the stereochemical results were identical, The cyanohydrins were transformed into the α-methyl α-hydroxyamides (e.e.-92%) by hydrolysis of the CN group and subsequent hydrogenolysis of the CS bond.

Nucleophilic addition of methyl 3-aminothiophene-2-carboxylate (2) as well as of β-alanine ethyl ester (11) to one CN group of the salts 1 of alkyl dicyanoacetates, followed by cyclization, yielded 1,2,3,4-tetrahydro-4-oxothieno[3,2-d]pyridimine derivatives 6–10 (Scheme 1) and perhydropyrimidine derivatives 17–19 (Scheme 2), respectively.

Reactions of Group 8 metal ethynyls with tetracyanoethene afford tricyanovinylethynyl-metal derivatives, M{C[triple bond]CC(CN)=C(CN)(2)}(PP)Cp' [2; M = Ru, Os; PP = (PPh(3))(2), dppe; Cp' = Cp, Cp*; not all combinations]; a similar reaction occurs with the vinylidene RuCl(=C=CHPh)(PPh(3))Cp. Further replacement of a CN group in occurs with nucleophiles, while homo- and hetero-metallic derivatives are obtained by coordination of one of the remaining CN groups to other metal-ligand fragments.

The previously reported 14N NQR spectrum of the CN groups of Ba [Fe (CN) 5NO] · 3H2O (BNP) was shown to also contain lines of Na2 [Fe (CN) 5NO] · 2H2O used in the preparation of BNP. The number of NQR lines and their relative intensities in BNP confirmed that it has a Pbcm instead of a Pca21 space group at 293 K as previously assumed. The three CN sites found in BNP at room temperature are increased to five below 233 K and to eight below 131 K as a result of phase transitions. The effect on the NQR lines of the axial CN group of the disorder of some water molecules in BNP is also discussed.

The IR and Raman spectra have been determined of the products formed by low-temperature (−20°C) replacement of 2-MeTHF (2-methyltetrahydrofuran) in photochemically produced Cr(CO) 5 (2-MeTHF) by isocyanogen, CNCN. The IR spectra are interpreted in terms of the formation of an isonitrile and a nitrile complex, Cr(CO) 5 (CNCN) and Cr(CO) 5 (NCNC). A detailed study of the IR and Raman spectra of Cr(CO) 5 (CNCN), which was formed in large excess, reveals that the coordinating CN group of CNCN has coordinating and vibrational properties almost identical to those of the CO ligands in this complex.

Normally disfavored 5-endo-trig cyclizations proceed in N-homoallylsulfonamides bearing a CF(3), CCl(3), CO(2)Et or CN group at the C-3 position, via an intramolecular S(N)2'-type or addition reaction to construct pyrrolidine rings, even though the system allows a more favorable 5-exo-trig pathway.

A theoretical study on the mechanism of the OH reactions with HCN and CH(3)CN, in the presence of O2, is presented. Optimum geometries and frequencies have been computed at BHandHLYP/6-311++G(2d,2p) level of theory for all stationary points. Energy values have been improved by single-point calculations at the above geometries using CCSD(T)/6-311++G(2d,2p). The initial attack of OH to HCN was found to lead only to the formation of the HC(OH)N adduct, while for CH(3)CN similar proportions of CH(2)CN and CH(3)C(OH)N are expected. A four-step mechanism has been proposed to explain the OH regeneration, experimentally observed for OH + CH(3)CN reaction, when carried out in the presence of O2. The mechanism steps are as follows: (1) OH addition to the C atom in the CN group, (2) O2 addition to the N atom, (3) an intramolecular H migration from OH to OO, and (4) OH elimination. This mechanism is in line with the one independently proposed by Wine et al. for HCN. The results obtained here suggest that for the OH + HCN reaction, the OH regeneration might occur even in larger extension than for OH + CH(3)CN reaction. The agreement between the calculated data and the available experimental evidence on the studied reactions seems to validate the mechanism proposed here.

Starting from experimental data on the synthesis of solid LiBC 4 N 4 , an ab initio study has been carried out within the DFT-LDA framework of its structure and completed by accounting for other potential cubic arrangements. The consideration of stabilization energies confirms the experimental phase as the most stable one but predicts some other potential arrangements. The system is found very compressible with a bulk modulus close to that of gypsum ( B 0 = 35 GPa). The electronic structure characteristics are provided allowing to confirm an ionic behavior involving complex anionic species (Li + [B(CN) 4 ] − ). The control of the crystal cell size by a stoichiometry modification, such as by a CN group substitution is also studied. The proposition of LiBX 4 and LiBS 4 N 4 stoichiometries leads to predict new materials.

Direct synthesis of functionalised hard spheres obtained starting from 1,2-bis(triethoxysilyl)ethane (BTSE) as silica precursor is reported. –SH organic moiety comes from 3-mercaptopropyltrimethoxysilane (MPTMS) and –CN is obtained from 3-cyanopropyltriethoxysilane (CPTES) reagents, respectively. –CN group was hydrolysed in order to obtain –COOH functional group. Syntheses follow S + X – I + assembly pathways.

Vibrational sum-frequency spectroscopy and surface tensiometry have been used to study the adsorption of m- and p-cyanophenol at the air-water interface. Spectra of the cyano (CN) group under different polarization schemes are utilized to determine its hydrogen bonding environment and orientation. For both isomers, it is found that the cyano group is hydrogen bonded at the interface but that the CN orientation is independent of surface density. The average CN tilt angle (theta(0)), however, is found to differ between the isomers, such that the CN group points down toward the aqueous phase for m-cyanophenol (theta(0) = 96-106 degrees ) but points up toward the vapor phase for the p-cyanophenol (theta(0) = 65-80 degrees ). In addition, this average tilt angle is distributed over a narrow range, sigma(0)10 degrees for the meta isomer and sigma(0)16 degrees for the para isomer.

In the title complex, [CuNi(CN) 4 (C 4 H 13 N 3 )(C 2 H 7 NO)].2H 2 O, the Cu atom, chelated by a terdentate dien [dien = N-(2-aminoethyl)-1,2-ethanediamine] and a bidentate mea (mea = 2-aminoethanol) ligand, is ligated additionally with [Ni(CN) 4 ] 2- monodentately at the N atom of one CN group; the three other N atoms are free from ligation. This is a rare example of tetracyanonickelate(II) bridging to another coordination centre through only one CN group.

Formation of the donor-acceptor complexes of group 13 metal derivatives with nitriles and isonitriles X(3)M-D (M = Al,Ga,In; X = H,Cl,CH(3); D = RCN, RNC; R = H,CH(3)) and their subsequent reactions have been theoretically studied at the B3LYP/pVDZ level of theory. Although complexation with MX(3) stabilizes the isocyanide due to the stronger M-C donor-acceptor bond, this stabilization (20 kJ mol(-1) at most) is not sufficient to make the isocyanide form more favorable. Relationships between the dissociation enthalpy DeltaH degrees (298)(diss), charge-transfer q(CT), donor-acceptor bond energy E(DA), and the shift of the vibrational stretching mode of the CN group upon coordination Deltaomega(CN) have been examined. For a given metal center, there is a good correlation between the energy of the donor-acceptor bond and the degree of a charge transfer. Prediction of the DeltaH degrees (298)(diss) on the basis of the shift of CN stretching mode is possible within limited series of cyanide complexes (for the fixed M,R); in contrast, complexes of the isocyanides exhibit very poor Deltaomega(CN) - DeltaH degrees (298)(diss) correlation. Subsequent X ligand transfer and RX elimination reactions yielding monomeric (including donor-acceptor stabilized) and variety of oligomeric cage and ring compounds with [MN]n, [MC]n, [MNC]n cores have been considered and corresponding to thermodynamic characteristics have been obtained for the first time. Monomeric aluminum isocyanides X(2)AlNC are more stable compared to Al-C bonded isomers; for gallium and indium situation is reversed, in qualitative agreement with Pearson's HSAB concept. Substitution of X by CN in MX(3) increases the dissociation enthalpy of the MX(2)CN-NH(3) complex compared to that for MX(3)-NH(3), irrespective of the substituent X. Mechanisms of the initial reaction of the X transfer have been studied for the case X = R = H. The process of hydrogen transfer from the metal to the carbon atom in H(3)M-CNH is thermodynamically favorable and is likely to be intramolecular. By contrast, intramolecular hydrogen transfer in H(3)M-NCH has been definitely ruled out. Head-to-tail dimeric species [H(3)M-(NC)H](2) are formed exothermically and exhibit low H.H distances, which can assist in hydrogen transfer, and are likely to be the starting point for H(2) elimination. Elimination of H(2), CH(4), and C(2)H(6) from X(3)M-(NC)R adducts is very favorable thermodynamically; by contrast, elimination of HCl and CH(3)Cl is highly unfavorable even if formation of oligomer species takes place. Thus, high-temperature generation of gas-phase rings and clusters has been predicted viable in the cases X = H,CH(3) and their presence in the reactor media should not be neglected. Moderate stability of [HMCH(2)NH](4) clusters (especially in the cases M = Ga, In) makes these species viable intermediates of gas-phase reactions. Their formation may be responsible for the carbon contamination in the course of metal organic chemical vapor deposition processes of group 13 binary nitrides.

Density functional (B3LYP) calculations, using the 6-31G basis set, have been employed to study the title reactions. For the model reaction (H(2)C=C-NH(+)=CH(2) + H(2)C=CH(2)), a complex has been formed with 6.2 kcal/mol of stabilization energy and the transition state is 4.0 kcal/mol above this complex, but 2.1 kcal/mol below the reactants. However, the substituent effects are quite remarkable. When ethene is substituted by electron-withdrawing group CN, the reaction could also yield six-membered-ring products, but the energy barriers are all more than 7 kcal/mol, which shows that CN group unfavors the reaction. The other substituents, such as CH(3)O and CH(3) groups, have also been considered in the present work, and the results show that they are favorable for the formation of six-membered-ring adducts. The calculated results have been rationalized with frontier orbital interaction and topological analysis.

The compound [(CH(3))C(NH(2))(2)](4)[Re(6)Se(8)(CN)(6)] has been synthesized by the reaction at 200 degrees C for 3 days of Re(4)Te(4)(TeCl(2))(4)Cl(8), KSeCN, and NH(4)Cl in superheated acetonitrile. This compound crystallizes in the space group C2/c of the monoclinic system with four formula units in a cell of dimensions a = 20.3113(14) A, b = 10.1332(7) A, c = 19.9981(14) A, beta = 106.754(1) degrees, V = 3941.3(5) A(3) (T = 153 K). The [Re(6)Se(8)(CN)(6)](4-) anion comprises an Re(6) octahedron face capped by mu(3)-Se atoms, with each Re atom liganded by a CN group. The anions and cations are connected by an extensive network of hydrogen bonds. The conversion of a Re(IV) tetrahedral cluster to a Re(III) octahedral cluster appears to be unprecedented.

The compound [(CH(3))C(NH(2))(2)](4)[Re(6)Se(8)(CN)(6)] has been synthesized by the reaction at 200 degrees C for 3 days of Re(4)Te(4)(TeCl(2))(4)Cl(8), KSeCN, and NH(4)Cl in superheated acetonitrile. This compound crystallizes in the space group C2/c of the monoclinic system with four formula units in a cell of dimensions a = 20.3113(14) A, b = 10.1332(7) A, c = 19.9981(14) A, beta = 106.754(1) degrees, V = 3941.3(5) A(3) (T = 153 K). The [Re(6)Se(8)(CN)(6)](4-) anion comprises an Re(6) octahedron face capped by mu(3)-Se atoms, with each Re atom liganded by a CN group. The anions and cations are connected by an extensive network of hydrogen bonds. The conversion of a Re(IV) tetrahedral cluster to a Re(III) octahedral cluster appears to be unprecedented.

Surface pressure-mean molecular area isotherms of Langmuir films of some liquid crystals with CN or --NCS terminal group as well as of their binary mixtures have been recorded. It was found that only the liquid crystals which molecules have CN group are able to form a stable monolayer at the air-water interface. Information about the molecular organization and intermolecular interaction in two dimensional layer has been obtained. Moreover, the miscibility or phase separation of two components in the mixtures of various compositions has been determined by using excess area criterion and surface phase rule.

Rhombohedral crystal phase of CuCN forms irreversibly on heating a mixture of its orthorhombic and monoclinic phases to 593 K. In its space group, $R3m$ $(a=b=0.6026 \mathrm{nm},$ $c=0.4823 \mathrm{nm},$ $\ensuremath{\alpha}=\ensuremath{\beta}=90\ifmmode^\circ\else\textdegree\fi{},$ $\ensuremath{\gamma}=120\ifmmode^\circ\else\textdegree\fi{},$ $Z=3,$ ${V}_{0}=0.1516 {\mathrm{nm}}^{3},$ and ${D}_{x}=2.94 {\mathrm{g}/\mathrm{c}\mathrm{m}}^{3}),$ positions of C and N atoms are disordered, and therefore orientations of the CN group in the (N-Cu-C) chain structure are random. Its heat capacity increases in the manner of a sigmoid shape over the 350--380 K range, analogous to that observed on kinetic unfreezing of a canonical glass, as does that of a mixture of crystal phases obtained by flocculation process. The CuCN phase appears as the simplest orientational glass whose state is trapped in a deep minimum with a corrugated bottom, and each corrugation corresponding to one configurational excitation.

Treatment of 1-R-2 chloroperimidines with potassium or sodium cyanides in DMSO solution leads to facile substitution of the chlorine atom by the CN group and formation of previously unknown 1-R-2-cyanoperimidines. The latter upon heating in polyphosphoric acid are converted to 1-R-2-carbomoylperimidines in good yield.

The direct photolysis at 254 nm of 4-pyridinecarbonitrile in the presence of some aliphatic secondary amines brought to the substitution of the CN group and to the formation of 4-α-alkylaminopyridines, whereas the irradiation in the presence of benzophenone at 350 nm yields 4-alkylaminylpyridines and 4-di-phenylketylpyridine. A mechanism is proposed to explain the different course of the reaction under the two different conditions

In contrast to the monofunctinal compounds (i.e. 8,8-dimethylnonanenitrile and n-heptyltrimethylsilane) the Fe+ complex of 7-trimethylsilyheptanenitrile (2-Fe+) exhibits a unique reactivity in the gas phase which can only be explained by invoking a metal-ion-mediated cooperation of the SiMe3 and the CN group resulting in the regiospecific activation of C–H bonds. In contrast tot he Fe+ complexes of the monofunctional molecules, no C–C bond activation is observed for 2–Fe+.

In an acidic solution, the room-temperature reactions of CdX2 (X(-) = Cl(-), Br(-) or CH3COO(-)) and organic N-heterocyclic molecules with or without SCN(-)/SeCN(-)/dca(-) (dca(-) = dicyanamide) created the five new hybrid Cd(ii) compounds [H2(4,4'-dtdpy)]2[CdBr4]SO4·2.5H2O (dtdpy = dithiodipyridine) 1, [H(2,2'-dtdpy)]2[CdBr4] 2, [(Hbim)2CdCl2(SCN)2] (bim = 2,2'-biimidazole) 3, [H2(pip)][Cd(SCN)4] (pip = piperazine) 4 and [CdL2] (L = HNC(OH)N(-)CN) 5. X-ray single-crystal diffraction analysis revealed that: (i) compound 1 is a double salt of [H2(4,4'-dtdpy)]SO4 and [H2(4,4'-dtdpy)][CdBr4], [H2(4,4'-dtdpy)]SO4 shows a two-dimensional (2D) supramolecular layer structure and [H2(4,4'-dtdpy)][CdBr4] is distributed in the space between the supramolecular layers; (ii) compounds 2 and 3 are mononuclear molecular entities. Of those, 2,2'-dtdpy and bim were only in situ monoprotonated; (iii) compound 4 contains a 2D supramolecular layered structure which is based on [Cd(SCN)4](2-) chains H2(pip)(2+)via NSCNNpip interactions; (iv) the three-dimensional (3D) compound 5 exhibits a rutile-related (4·6(2))2(4(2)·6(10)·8(3))-topology. The ligand L originates from the in situ nucleophilic addition of H2O with one -CN group of dca(-). Upon excitation, the solid-state compounds 3 and 4 emit blue light, and the solid-state compound 5 emits violet light.

A new class of second order nonlinear optical chromophores resulted from the replacement of the most reactive CN group in tricyanovinylthiophene derivatives with aryl units, have been designed and synthesized. It was shown that these chromophores provide excellent tradeoffs among many relevant properties such as molecular nonlinearity, linear absorption at 830 nm, inherent thermal stability, chemical stability in processing solvents as well as host polymer matrices at high temperatures and attenuation at 830 nm.

In the title compound, C(10)H(10)N(4)O, the dihedral angle between the pyridine ring and the -C=O(CH(2))CN group is 24.08 (12)°. In the crystal, inversion dimers linked by pairs of N-H⋯N hydrogen bonds generate R(2) (2)(8) loops.