Cyanomethyl Research Articles

THE POSSIBLE INTERSTELLAR ANION CH2CN–: SPECTROSCOPIC CONSTANTS, VIBRATIONAL FREQUENCIES, AND OTHER CONSIDERATIONS

It is hypothesized that the A ^1B_1 <- X ^1A' excitation into the dipole-bound state of the cyanomethyl anion (CH2CN-) is proposed as the carrier for one diffuse interstellar band. However, this particular molecular system has not been detected in the interstellar medium even though the related cyanomethyl radical and the isoelectronic ketenimine molecule have been found. In this study we are employing the use of proven quartic force fields and second-order vibrational perturbation theory to compute accurate spectroscopic constants and fundamental vibrational frequencies for ^1A' CH2CN- in order to assist in laboratory studies and astronomical observations.

Trinuclear and tetranuclear manganese clusters derived from cyano(imino(methoxy)methyl)nitrosomethanide (cmnm)

Three manganese clusters have been synthesised via the reaction of MnII with cyano(imino(methoxy)methyl)nitrosomethanide (cmnm), obtained from the in situ nucleophilic addition of MeOH to dicyanonitrosomethanide (dcnm). X-ray crystallographic studies show that the complex [MnII3(cmnm)6]·MeOH (1) is a linear trinuclear species, with a central octahedral and two outer trigonal-prismatic manganese(II) ions. Two mixed-valent tetranuclear complexes [MnII2MnIII2O2(cmnm)4Cl2(MeOH)6] (2) and [MnII2MnIII2O2(cmnm)4Cl2(MeOH)4(pzH)2]·2MeOH (3) (pzH=pyrazole) contain two MnII and two MnIII ions in butterfly-type structures, with the six-coordinate ‘body’ MnIII ions bridged to the seven-coordinate ‘wingtip’ MnII ions by μ3-O2− and by nitroso oxygen atoms of the cmnm ligands. The formation of the trinuclear and tetranuclear manganese clusters is dependent on the stoichiometry used in the reactions. Solid state DC magnetic susceptibility studies on complexes 1 and 3 reveal that antiferromagnetic interactions are dominant within the clusters. Fits of the data reveal an S=5/2 ground state for 1 and a S=0 ground state for 3, with several close lying excited states found in both cases.

Ni(dmit)2]− salt with flexible supramolecular cation rotator

Abstract [Ni(dmit)2]− salt (dmit2− 2-thioxo-1,3-dithiole-4,5-dithiolate) with flexible supramolecular cation (4-cyanomethylanilinium)(dibenzo[18]crown-6) has been synthesized and investigated its structure, magnetism and rotation. The comparable large steric hindrances limit the rotation of cyanomethyl group to result in no phase transition occurred. Magnetic and potential energy calculations by DFT method were consistent with the magnetic and structure measurements.

Synthesis and magnetic properties of a series of 3d/4f/3d heterometallic trinuclear complexes incorporating in situ ligand formation

The dicyanonitrosomethanide (dcnm) ligand undergoes an in situ transition metal promoted nucleophilic addition of methanol to a nitrile group to form cyano(imino(methoxy)methyl)nitrosomethanide (cmnm) in the formation of the 3d/4f heterometallic complexes (Me4N)[{Ni(cmnm)3}2Ln(cmnm)2] (1Ln; 1Ln=1La, 1Ce, 1Pr, 1Nd, 1Sm). A change in the counter-ions of the metal and ligand salts employed under alternate reaction conditions results in the formation of (Et4N)2[{Ni(cmnm)3}2Ln(dcnm)2](ClO4) (2Ln; 2Ln=2La, 2Ce), in which unreacted dcnm ligands are coordinated to the central lanthanoid. In both types of complexes three cmnm ligands chelate to a nickel metal centre to form a [Ni(cmnm)3] metalloligand. Two of these metalloligands are then bound to a central lanthanoid via the nitroso oxygen atoms, resulting in a trinuclear complex in which each nickel cation is connected to the lanthanoid by three bridging nitroso groups. Variable temperature magnetic susceptibilities on these {Ni(S=1), Ln(f0 to f5), Ni(S=1)} spin systems reveal very weak to zero Ln–Ni or Ni–Ni exchange coupling with the thermal depopulation between Stark levels on the Ln centres being of similar magnitude, and the Ni2Ce and Ni2Pr cases giving strongest evidence for exchange coupling.

Linear Trinuclear Copper(II) Complexes Derived from the Nucleophilic Addition Products of Dicyanonitrosomethanide [C(CN)2(NO)]–: Syntheses, Structures, and Magnetic Properties

Two novel trinuclear CuII complexes have been synthesised from the nucleophilic addition derivatives of the small cyano anion, dicyanonitrosomethanide (dcnm). The reaction of CuII with the water adduct ligand, carbamoylcyanonitrosomethanide (ccnm) and teaH3 (triethanolamine) in a basic MeOH/MeCN solution results in the formation of [Cu3(acnm)2(teaH2)2]·2MeOH (1) (acnm = amidocarbonyl(cyano)nitrosomethanide and teaH2– = singly deprotonated triethanolamine). The reaction of CuII with dicyanonitrosomethanide (dcnm) and m-xylenediamine in a basic MeOH/MeCN solution results in the formation of [Cu3(cimm)2(a3acnm)2]·6MeCN (2) (cimm = cyano(imido(methoxy)methyl)nitrosomethanide and a3acnm = {amino(3-aminomethylphenyl)methylimino}methyl(cyanonitrosomethanide)). Both complexes display linear trinuclear CuII metallic cores. Solid state DC magnetic susceptibility studies were performed on 1 and 2. Compound 1 revealed very strong antiferromagnetic interactions between central and terminal Cu atoms, while compound 2 displayed ferromagnetic interactions because of the orthogonal relationship of the terminal and the central ‘magnetic’ orbitals, which contrasts with these orbitals being coplanar in 1 thus providing strong superexchange pathways involving Cu-N-O-Cu moieties.

In situ ligand formation in the synthesis of an octanuclear dysprosium ‘double cubane’ cluster displaying single molecule magnet features

The nucleophilic addition of methanol and water to the dicyanonitrosomethanide anion, resulting in the formation of cyano(imino(methoxy)methyl)nitrosomethanide (cmnm) and carbamoylcyanonitrosomethanide (ccnm), respectively, is used as a means of in situ ligand synthesis during the formation of [Dy(8)(OH)(6)(OMe)(6)(cmnm)(10)(ccnm)(2)(H(2)O)(2)(MeOH)(2)] (1). This is the first time these reactions have been observed to be promoted by the presence of a lanthanoid ion. The core of the octanuclear cluster consists of two cubane moieties ([Dy(4)(OH)(3)(OMe)]), bridged by four methoxide ligands to form a central [Dy(8)(OH)(6)(OMe)(6)] moiety. The complex displays magnetic properties that are indicative of probable single molecule magnet features.

Synthesis of cyclic carbonates from CO2 and diols via electrogenerated cyanomethyl anion

AbstractThe electrogenerated cyanomethyl anion reacts with diols in the presence of CO2 to yield the corresponding cyclic carbonates in moderated yields. The reported methodology has been carried out under mild conditions, avoiding any addition of classical bases, catalysts. In this communication, the effects of reaction conditions – such as supporting electrolyte, cathode material, current densities, charge amount, diol concentration – have been investigated to optimize the carbonates yield. © 2011 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Matrix Infrared Spectra and Density Functional Calculations of the H2CCN and H2CNC Radicals Produced from CH3CN

The H(2)CCN and H(2)CNC radicals are observed in matrix IR spectra from acetonitrile exposed to radiation from laser ablation of transition metals, whereas cyc-H(2)CCN, another plausible isomer, is not. Density functional frequency calculations and D and (13)C isotopic substitutions substantiate the vibrational assignments. The cyano methyl radical converts to the 95 kJ/mol higher energy isocyano counterpart on uv photolysis. Computations show that the cyclic isomer is a shallow energy minimum between two transition states. Intrinsic reaction coordinate calculations indicate that conversion between the two products is feasible via the cyclic configuration.

Runoff Transport of Pyrethroids from a Residential Lawn in Central California

An irrigation runoff study on a residential lawn was conducted in California, northeast of Sacramento, during the summer and fall of 2008 to investigate the contribution of turf uses of pyrethroids to residues in Californian urban creek sediments. This study examined how over irrigation (i.e., irrigation that produces runoff) in the summer season may transport recently applied pyrethroids. The study included liquid and granular applications of both bifenthrin [(2-methyl-3-phenyl-phenyl) methyl 3-(2-chloro-3,3,3-trifluoro-prop-1-enyl)-2,2-dimethyl-cyclopropane-1-carboxylate] and beta-cyfluthrin [Cyano(4-fluoro-3-phenoxyphenyl)methyl 3-(2,2-dichloroethenyl)-2,2-dimethyl-cyclopropanecarboxylate]. Generally, runoff did not occur at irrigation rates of 2.03 cm/h (0.8 in/h) but did occur when the irrigation rates were increased to about 3.81 cm/h (1.5 in/h), generating chemical losses in the first runoff event of up to 0.58 and 0.08% of applied for beta-cyfluthrin and bifenthrin, respectively. Chemical runoff losses dropped significantly between over-irrigation events with the third over-irrigation event chemical runoff losses representing 0.026 and 0.015% of applied for beta-cyfluthrin and bifenthrin, respectively. Runoff losses were generally less for liquid formulations than granular formulations but within a factor of three. Additionally, the study included a simulated winter rainstorm 8 wk after application. The low runoff losses from turf seen in this study suggest that other sources could be contributing to observed residues in urban streams. Other sources could include pyrethroids ending up on impervious surfaces, such as concrete driveways from off-target applications to turf, spills, and other poor handling practices, or pyrechroids applied directly to impervious surfaces for insect control.

Development of fluorescent substrates for microsomal epoxide hydrolase and application to inhibition studies

The microsomal epoxide hydrolase (mEH) plays a significant role in the metabolism of numerous xenobiotics. In addition, it has a potential role in sexual development and bile acid transport, and it is associated with a number of diseases such as emphysema, spontaneous abortion, eclampsia, and several forms of cancer. Toward developing chemical tools to study the biological role of mEH, we designed and synthesized a series of absorbent and fluorescent substrates. The highest activity for both rat and human mEH was obtained with the fluorescent substrate cyano(6-methoxy-naphthalen-2-yl)methyl glycidyl carbonate ( 11). An in vitro inhibition assay using this substrate ranked a series of known inhibitors similarly to the assay that used radioactive cis-stilbene oxide but with a greater discrimination between inhibitors. These results demonstrate that the new fluorescence-based assay is a useful tool for the discovery of structure–activity relationships among mEH inhibitors. Furthermore, this substrate could also be used for the screening chemical library with high accuracy and with a Z′ value of approximately 0.7. This new assay permits a significant decrease in labor and cost and also offers the advantage of a continuous readout. However, it should not be used with crude enzyme preparations due to interfering reactions.

Cytochrome P450 6M2 from the malaria vector Anopheles gambiae metabolizes pyrethroids: Sequential metabolism of deltamethrin revealed

Resistance to pyrethroid insecticides in the malaria vector Anopheles gambiae is a major threat to malaria control programmes. Cytochome P450-mediated detoxification is an important resistance mechanism. CYP6M2 is over-expressed in wild populations of permethrin resistant A. gambiae but its role in detoxification is not clear. CYP6M2 was expressed in Escherichia coli and a structural model was produced to examine its role in pyrethroid metabolism. Both permethrin and deltamethrin were metabolized. Rates were enhanced by A. gambiae cytochrome b5 with kinetic parameters of KM=11±1μM and kcat=6.1±0.4 per min for permethrin (1:1 cis–trans) and KM=2.0±0.3μM and kcat=1.2±0.1 per min for deltamethrin. Mass spectrometry and NMR analysis identified 4′-hydroxy deltamethrin and hydroxymethyl deltamethrin as major and minor deltamethrin metabolites respectively. Secondary breakdown products included cyano(3-hydroxyphenyl)methyl deltamethrate and deltamethric acid. CYP6M2 was most highly transcribed in the midgut and Malpighian tubules of adult A. gambiae, consistent with a role in detoxification. Our data indicates that CYP6M2 plays an important role in metabolic resistance to pyrethroids and thus an important target for the design of new tools to combat malaria.

Unexpected formation of ethyl 5-cyano-6-[cyano(4′-phenyl-1,3′-selenazol-2-yl)methyl]-4-(furan-2′-yl)-2-methyl-1,4-dihydropyridine-3-carboxylate

Unexpected formation of ethyl 5-cyano-6-[cyano(4′-phenyl-1,3′-selenazol-2-yl)methyl]-4-(furan-2′-yl)-2-methyl-1,4-dihydropyridine-3-carboxylate

Structural phase transition due to the flexible supramolecule of (4-cyanomethylanilinium)([18]crown-6) in [Ni(dmit)2]− crystal

A flexible hydrogen-bonding supramolecular cation of 4-cyanomethylanilinium (CMAni+)-[18]crown-6 was introduced into the [Ni(dmit)2]− salt (dmit2− = 2-thioxo-1,3-dithiole-4,5-dithiolate) as a counter cation to form (CMAni+)([18]crown-6)[Ni(dmit)2]−. The rotation of the cyanomethyl group of the CMAni+ cation is associated with the structural phase transition at 153 K, at which temperature the space group was changed from Pbcn (high-temperature phase) to P212121 (low-temperature phase). The temperature dependent dielectric constants and potential energy calculations were consistent with the rotation of the cyanomethyl group of CMAni+.

Theoretical and Experimental Insights into the Mechanism of the Nucleophilic Addition of Water and Methanol to Dicyanonitrosomethanide

In this work the nucleophilic addition of water and methanol to the dicyanonitrosomethanide anion (dcnm, [C(CN)(2)(NO)](-)) in the absence of the usual transition metal promoters was investigated. Experimentally it was shown that a quantitative conversion of the dcnm anion to carbamoylcyanonitrosomethanide (ccnm, [C(CN)(CONH(2))(NO)](-)) by the addition of 1 equiv of water to a nitrile group is complete in 48 h at 100 °C, or in 1.5 h at 150 °C when the reaction is conducted in a microwave reactor. Attempts to add a second equivalent of water to the anion failed with thermal degradation of the anion occurring at 200 °C. Ab initio calculations show that the reaction proceeds via three distinct transition states: (1) the transfer of a proton from a water molecule to the nitrile group, (2) the subsequent attack of the generated hydroxide anion on the carbon atom of the nitrile group, and (3) a rapid proton transfer to form a carbamoyl group. The attacking water molecule is shown to be a stronger proton donor when modeled as part of a hydrogen-bonded three water molecule chain, leading to a significant reduction in the reaction barrier. Only the anti-ccnm anion is formed in the reaction. There is a high-energy barrier to the formation of the syn isomer by the rotation of the nitroso group. While the syn isomer of ccnm is shown to be the more thermodynamically stable conformation, examination of the HOMO-1 molecular orbital that arises during the second transition state of the reaction indicates the addition of the hydroxide anion to the carbon atom is forbidden due to orbital symmetry, with a similar effect responsible for the failure of a second equivalent of water to add to the ccnm anion. Under analogous reaction conditions the addition of 1 equiv of methanol to dcnm to form cyano(imino(methoxy)methyl)nitrosomethanide (cmnm, [C(CN)(C(OMe)NH)(NO)](-)) failed, although ab initio calculations initially indicated the reaction should proceed more readily than the addition of water. When the energy required to break the hydrogen-bonded cyclic hexamers in methanol is taken into consideration, the energy barrier to the first transition step is greatly increased. The addition of a second equivalent of methanol to cmnm is unlikely to occur even in the presence of a transition metal as the resultant anion would be marginally thermodynamically unstable.

Electrografting of the cyanomethyl radical onto carbon and metal surfaces

Nanometer layers are grafted on the surface of carbon or metallic electrodes by electrochemical reduction of iodo or bromoacetonitrile in acetonitrile. The structure of these layers, ( carbon or metal)–[CH 2–CH(NH 2)–] n , is determined by electrochemistry, ellipsometry and IRRAS. The bond between the surface and the organic layer is evidenced by ToF-SIMS. A mechanism is proposed to account for the formation of the layers: the grafting is assigned to the reaction of the cyanomethyl radical, CH 2CN, with the electrode surface and the latter is partly reduced to the cyanomethyl anion −CH 2CN that attacks the first grafted –CH 2CN group, leading to the growth of the layer. It is also possible to produce the same radical by oxidation of the −CH 2CN anion -obtained by deprotonation of acetonitrile-, but in this case only traces of grafting are detected on the electrode as the radical is trapped by the large excess of anions.

ChemInform Abstract: Light-Mediated Cyanomethylation of Cycloalkenes with Acetonitrile.

Addition of cyanomethyl radicals generated from acetonitrile involving initiation by photoinduced decomposition of hydrogen peroxide, to cycloalkenes has been achieved; a method for the synthesis of two homologous nitriles is first reported.

Minor crops for export: A case study of boscalid, pyraclostrobin, lufenuron and lambda-cyhalothrin residue levels on green beans and spring onions in Egypt

Dissipation rates of boscalid [2-chloro-N-(4′ -chlorobiphenyl-2-yl)nicotinamide], pyraclostrobin [methyl 2-[1-(4-chlorophenyl) pyrazol-3-yloxymethyl]-N-methoxycarbanilate], lufenuron [(RS)-1-[2,5-dichloro-4-(1,1,2,3,3,3-hexafluoropropoxy)phenyl]-3-(2,6-difluorobenzoyl)urea] and λ-cyhalothrin [(R)-cyano(3-phenoxyphenyl)methyl (1S,3S)-rel-3-[(1Z)-2-chloro-3,3,3-trifluoro-1-propenyl]-2,2-dimethylcyclopropanecarboxylate] in green beans and spring onions under Egyptian field conditions were studied. Field trials were carried out in 2008 in a Blue Nile farm, located at 70 kilometer (km) from Cairo (Egypt). The pesticides were sprayed at the recommended rate and samples were collected at pre-determined intervals. After treatment (T0) the pesticide residues in green beans were 7 times lower than in spring onions. This is due to a different structure of vegetable plant in the two crops. In spring onions, half-life (t1/2) of pyraclostrobin and lufenuron was 3.1 days and 9.8 days respectively. At day 14th (T14) after treatment boscalid residues were below the Maximum Residue Limit (MRL) (0.34 versus 0.5 mg/kg), pyraclostrobin and λ -cyhalothrin residues were not detectable (ND), while lufenuron residues were above the MRL (0.06 versus 0.02 mg/kg). In green beans, at T0, levels of boscalid, lufenuron and λ -cyhalothrin were below the MRL (0.28 versus 2 mg/kg; ND versus 0.02 mg/kg; 0.06 versus 0.2 mg/kg, respectively) while, after 7 days treatment (T7) pyraclostrobin residues were above the MRL (0.03 versus 0.02 mg/kg). However, after 14 days the residue level could go below the MRL (0.02 mg/kg), as observed in spring onions.

ChemInform Abstract: Rearrangement of the Cyanomethyl Group in Cycloammonium Zwitterions Generated from Spiro‐4‐cyanomethyl‐3‐methyl‐1,2,3,4,5,6‐hexahydrobenzo [f]isoquinolinium‐1,2′‐(1′,2′,3′,4′‐tetrahydronaphthalen‐1′‐one) Chloride.

ChemInform Abstract: Rearrangement of the Cyanomethyl Group in Cycloammonium Zwitterions Generated from Spiro‐4‐cyanomethyl‐3‐methyl‐1,2,3,4,5,6‐hexahydrobenzo [f]isoquinolinium‐1,2′‐(1′,2′,3′,4′‐tetrahydronaphthalen‐1′‐one) Chloride.

4-(Cyanomethyl)anilinium 4-methylbenzenesulfonate monohydrate

In the title salt, C8H9N2 +·C7H7O3S−·H2O, the dihedral angle between the cation and anion benzene rings is 50.1 (4)°. In the cation, the cyano­methyl group is twisted from the plane of the benzene ring [C—C—C—N = −86 (12)°]. In the crystal, the cations, anions and water mol­ecules are linked by N—H⋯O and O—H⋯O hydrogen bonds, forming a chain along the c axis.

Indirect Grafting of Acetonitrile-Derived Films on Metallic Substrates

Strongly bonded organic films with amino groups are obtained on gold, copper, and silicon surfaces by reduction of 2,6-dimethyl benzenediazonium in acetonitrile (ACN). The sterically hindered 2,6-dimethylphenyl radical is unable to attach to the surface, but it abstracts an hydrogen atom from ACN to give the cyanomethyl radical (·CH2CN) that reacts with the surface. A spontaneous reaction is also possible on copper. The film is characterized by IR spectroscopy, scanning electron microscopy, ellipsometry, water contact angles, and cyclic voltammetry. A mechanism is elaborated that accounts for the formation, grafting of the cyanomethyl radical, and finally formation of amino multilayers.