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The direct synthesis of cyclohexylamine via the hydrogenation of nitrobenzene over monometallic (Pd, Ru or Rh) and bimetallic (PdxRu1−x) catalysts was studied. The Pd0.5Ru0.5-PVP catalyst was the most effective catalyst for this reaction. The catalyst can be reused and applied for the synthesis of N-aryl pyrroles and quinoxalines from nitrobenzenes.

1,3-Dichloro-1,3-bis(dimethylamino)propenium salts react with primary amines to give different products depending on the structure of the amine. Reactions in which the primary amine is bonded to a tertiary carbon (tert-butylamine and 1-adamantylamine) result in 1,1-bis(dimethylamino)-3,3-bis(alkylamino)propenium salts which form via a 1,3-dimethylamino shift. In contrast, the reactions in which the primary amine is bonded to a secondary carbon (cyclohexylamine, cyclopentylamine, and sec-butylamine) result in 1-(ylidene)amino-1,3-bis(dimethylamino)propenium salts which form via an intramolecular hydride shift. All of the synthesized compounds have been fully characterized using spectroscopic methods, including single crystal X-ray diffraction. Finally, the mechanisms of the intramolecular rearrangements have been investigated computationally at the ωB97X-D/6-311G(d,p) level of theory, suggesting that the reactions proceed through putative keteniminium species.

Two bidentate PNP ligands N,N-bis(di-p-tolylphosphino)cyclohexylamine (Cy-pTolPNP) (1) and N,N-bis(di-p-tolylphosphino)cyclobutylamine (Cb-pTolPNP) (2) were synthesized and crystallized. Coordination to the fac-[MI(CO)3]+ core (M = Re, 99Tc) yielded fac-[Re(Cy-pTolPNP)(CO)3Br] (1A), fac-[99Tc(Cy-pTolPNP)(CO)3Cl] (1B), fac-[Re(Cb-pTolPNP)(CO)3Br] (2A) and fac-[99Tc(Cb-pTolPNP)(CO)3Cl] (2B) in relatively good yields (56 to 86 %): The structures of 1, 2, 1A and 1B were studied by single crystal X-ray crystallography. Preliminary mitochondrial/antimicrobial evaluation of the free ligand (N,N-bis(di-p-tolylphosphino)-cyclohexylamine) (1) and its respective fac-[Re(CO)3]+ (1A) complex indicates that neither the free ligand nor the complex was active against selected fungi Eremothecium ashbyii and Nadsonia fulvescens. In addition, all four compounds were found to have no activity against Gram-positive and Gram-negative bacterial species. These biological results are essential to the understanding of how these types of complexes behave and show they are perfectly stable in the evaluated bio-environments. In addition, the results indicate that these ligands and complexes may present themselves as excellent models for radiotoxicity studies using technetium-99m, but more specifically, rhenium Re-186 and Re-188.

The development of highly active and selective heterogeneous catalysts for efficient oxidation of cyclohexylamine to cyclohexanone oxime is a challenge associated with the highly sensitive nitrogen center of cyclohexylamine. In this work, dispersed Nb oxide supported on SBA-15 catalysts are disclosed to efficiently catalyze the selective oxidation of cyclohexylamine with high conversion (>75%) and selectivity (>84%) to cyclohexanone oxime by O2 without any addition of solvent (TOF = 469.8 h−1, based on the molar amount of Nb sites). The role of the active-site structure identity in dictating the site-specific catalytic activities is probed with the help of different reaction and control conditions and multiple spectroscopy methods. Complementary to the experimental results, further poisoning tests (with KSCN or dehydroxylation reagents) and DFT computational studies clearly unveil that the surface exposed active centers toward activation of the reactants are quite different: the surface –OH groups can catch the NH2 group from cyclohexylamine by forming a hydrogen bond and lead to a more facile cyclohexylamine oxidation to desired products, while the monomeric or oligomeric Nb sites with a highly distorted structure play a key role in the dissociation of O2 molecules beneficial for insertion of active oxygen species into cyclohexylamine. These catalysts exhibit not only satisfactory recyclability for cyclohexylamine oxidation but also efficiently catalyze the aerobic oxidation of a wide range of amines under solvent-free conditions.

A comparative model for the chemisorption of CO2 was explored via three representative reaction pathways: carboxylation of cyclohexanone, carbonation of cyclohexanol, and carbamation of cyclohexylamine. The model substrates were activated using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, an amidine superbase). For each of these reactions, the formation of the corresponding CO2 adducts was confirmed by 13C nuclear magnetic resonance and Fourier-transform infrared spectroscopy measurements. It was demonstrated that CO2 fixation occurred through either an enol-CO2 adduct (i.e. carboxylation), proton shuttling process (i.e. carbonation), or self-activation mechanism (i.e. carbamation). Volumetric adsorption measurements indicated that cyclohexanol was superior in its uptake capacity (11.7 mmol CO2 g−1 sorbent) in comparison to cyclohexylamine (9.3 mmol CO2 g−1 sorbent) or cyclohexanone (8.5 mmol CO2 g−1 sorbent). As supported by density functional theory calculations, this trend was expected given the fact that the carbonation reaction proceeded through a more thermodynamically favorable reaction process.

MCM-49 zeolite with a three-dimensional MWW framework was directly synthesized using low-toxicity and cost-effective cyclohexylamine (CHA) as an organic structure-directing agent under hydrothermal conditions. Compared with the traditional hexamethyleneimine template, the interaction between CHA with the framework was weaker and more CHA molecules occupied the surface pockets and supercages of as-synthesized MCM-49 zeolite. The obtained sample showed good catalytic performance in the liquid phase alkylation reaction of benzene with ethylene.

The selective N-monomethylation of amines is an important topic in fine chemical synthesis. Herein, for the first time, we described a selective N-monomethylation reaction of amines with paraformaldehyde and H2 in the presence of a CuAlOx catalyst. A variety of amines, including primary aromatic amines, benzylamine and cyclohexylamine, as well as secondary amines, have been shown to be compatible with this reaction.

Continuous handling of solids creates challenges for realizing continuous production of pharmaceuticals and fine chemicals. We present a new miniature continuous stirred-tank reactor (CSTR) cascade to handle solid-forming reactions in flow. Single-phase residence time distribution (RTD) measurements of the CSTR cascade reveal nearly ideal CSTR mixing behavior of the individual units. Consistency of experimental and predicted conversions of a Diels–Alder reaction further confirms the CSTR performance. Two solid-forming reactions, (i) glyoxal reacting with cyclohexylamine to form N,N′-dicyclohexylethylenediimine, (ii) sulfonylation of 2-octanol with methanesulfonyl chloride, demonstrate the ability of the reactor cascade to transport solid particles continuously for hours without significant signs of clogging.

The carbon supported 10% Ni catalysts doped with 3‰ Rh have been prepared by an impregnation method. These catalysts have been used to catalyze the one-step hydrogenation of nitrobenzene to cyclohexylamine. The results show that the 3‰ Rh–10% Ni/CSC (biocarbon) catalyst exhibits an excellent performance to achieve 100 mol% conversion of nitrobenzene and 91.6% selectivity of cyclohexylamine under reaction conditions of 3.5 MPa and 140 °C. The recycling tests reveal recyclable stability of 3‰ Rh–10% Ni/CSC. This catalyst is active for the hydrogenation of a series of electron-deficient nitrobenzenes. Some factors such as the type of carriers, the content of Ni and Rh, the type of metals and additives play important roles in controlling the selective hydrogenation.

TaOx grafted onto Al2O3 is investigated for C–N bond cleavage of amines under H2 pressure. Heteroaromatics such as aniline are stoichiometrically denitrogenated at high temperature, while cyclohexylamine is catalytically denitrogenated. UV-visible and X-ray photoelectron spectroscopy indicate the formation of a stable Ta–N species in the former case.

Kinetics and dynamics of the curing of bisphenol-A diglycidyl ether (DGEBA) with various agents i.e. cyclohexylamine, aniline and 2-ethylhexylamine, were investigated by means of Broadband Dielectric Spectroscopy (BDS) over a wide range of thermodynamic conditions. We proposed a novel method of dielectric data analysis to extract information on the progress of the curing reaction. This approach was validated by complementary calorimetry measurements. High pressure studies indicated that compression significantly reduces the time of the reaction. At the same time, a decrease in monomer conversion and the glass transition temperature of the recovered product was observed. This was due to vitrification of the system that occurs in a relatively short time. We found a linear correspondence between the time of the polymerization after which the investigated system undergoes glass transition and the degree of monomer conversion. Additionally, activation volumes for the investigated reactions were determined and found to lie in the range −18 and −38 cm3 mol−1. The calculated values are lower than ΔV estimated for the ring opening reaction provided in the literature. However our data unquestionably showed that this quantity depends strongly on both the chemical structure of the substrates as well as thermodynamic conditions.

A lot of ternary In-Sb-Q (Q = S, Se) chalcogenido-metalates with amines or complex cations have been recently reported for their diverse structures, however, such a type of In-Sn-Q chalcogenido-metalate has been rarely announced. Herein, we report a series of 2-D In-Sn-Q compounds prepared using a metal-phenanthroline cationic template, [M(Phen)3](In2Sn2Q8)·(amine)·nH2O (M = Ni(II), Fe(II) or Co(II); amine = cyclohexylamine (Cha) or 1,6-diaminohexane (Dah); Q = S or Se). Their anions are isostructural and a 2-D porous network with large 16-tetrahedron-rings. The 2-D network joint of In-Sn-Q is a (In/Sn)3Q3 six-membered ring, which is different from the Sn3Q4 pseudosemicube of most 2-D Sn-Q binary compounds. The materials exhibit photocurrent response properties measured using a photo-electrochemical cell. The result shows that (1) the selenides exhibit more intense photocurrents than the sulfides and (2) the current intensity is related to the metal-phenanthroline cations.

Corrosion inhibitors are widely used in the water industry for steam condensate treatment. Due to their application into the food industry, the Food and Drug Administration (FDA) legislate that such inhibitors are not to exceed 10 mg L−1. Various analytical protocols exist to provide an offsite analysis and a point of site analysis is required. Consequently, the first example has been reported for the indirect electroanalytical determination of cyclohexylamine and morpholine, two important corrosion inhibitors using disposable and economical screen-printed graphite macroelectrodes. These two analytes have been demonstrated to have no measureable direct electrochemical signatures in aqueous solutions using carbon and noble metal based macroelectrodes and we propose, for the first time, an indirect electrochemical sensing protocol which utilises screen-printed graphite macroelectrodes. This indirect approach utilises an EC type-mechanism using the compounds, N,N′-(1,4-phenylene)dibenzenesulfonamide and N-(4-amino-2-methyl-phenyl)-benzenesulfonamide as mediators. In this approach the mediators are electrochemically oxidised which then chemically react with the target analytes, cyclohexylamine and morpholine; the products of these reactions are then electrochemically interrogated and provide an indirect electroanalytical signal with which to quantify cyclohexylamine and morpholine. The two mediators are required for the two analytes as one mediator cannot measure both analytes. It is demonstrated that this indirect sensing protocol allows the electroanalytical detection of cyclohexylamine and morpholine over the range 1 to 10 mg L−1 in pH 10 carbonate buffer utilising cyclic voltammetry. This indirect electroanalytical protocol is found to exhibit a limit of detection (3σ) of 0.9 and 1 mg L−1 for cyclohexylamine and morpholine respectively which are significantly below the FDA sanctioned levels. This indirect electroanalytical protocol utilising screen-printed sensors has the potential to be applied into-the-field enabling the measurement of these two neutralizing amines to ensure they do not exceed FDA guidelines.

High-quality single-crystalline hollow α-Fe2O3 nanospheres were prepared, using the ZnS–CHA (CHA = cyclohexylamine) nanohybrid as an additive through a solvothermal reaction, which avoids tedious steps and a high temperature calcination process. The formation process of these hollow nanospheres can be divided into two stages: (i) formation of solid Fe2O3 nanospheres and (ii) preferential inside-out dissolution of the solid nanoparticles to form hollow nanospheres. Due to the unique single-crystalline hollow structure, the as-obtained α-Fe2O3 nanomaterial exhibits enhanced gas sensing properties.

Two novel pendant-armed dialdehydes (1a and 1b) were prepared by a one-step reaction between 5-chloro-3-(chloromethyl)-2-hydroxybenzaldehyde/5-methyl-3-(chloromethyl)-2-hydroxybenzaldehyde and cyclohexylamine involving two nucleophilic substitutions, and they were used to react with 1,3-propanediamine to prepare Schiff-base macrocyclic complexes in the presence of ZnX2 salts (X = Cl, Br, and I). As a result, five dinuclear (2a, 2b, 3b, 4a, and 4b) and one mononuclear (3a) [1 + 1] flexible macrocyclic Zn(II) complexes have been structurally and spectrally characterized. The zinc centers in three pairs of macrocyclic complexes have the common four-coordinate tetrahedral geometry with one or two coordinated halide ions, where the template Zn(II) cations and the auxiliary halide anions with different sizes and coordination abilities are believed to play important roles in forming the resulting macrocyclic complexes. In addition, subtle alterations of electron-withdrawing and electron-donating substituted groups (Cl versus CH3) in the macrocyclic backbone result in different (1)H NMR and UV-vis spectra.

Nanofibrils emitting strong red light have been fabricated from triphenylamine functionalized β-diketone-boron difluoride 1, via a rapid solution dispersion approach. It is found that the nanofibrils based on compound 1 can sense volatile organic amines and pyridine selectively. For example, the fluorescence of the nanofibril-based film can be quenched quickly and significantly upon exposed to the vapors of n-butylamine, dibutylamine, tributylamine, triethylamine, cyclohexylamine, hydrazine, aniline, N,N-dimethylaniline and pyridine instead of other common reagents. Notably, the response time of the nanofibril-based film to aniline is ca. 1.06 s, which is one of the fastest fluorescent responses to aniline. The detection limit of the nanofibril-based film for aniline vapor can reach ca. 100 ppb. We suggest that the high sensitivity and fast response of the sensory nanofibrils towards gaseous amines may come from the high surface-to-volume ratio and large interspace in the nanofibril-based networks, which favor the enhanced adsorption, accumulation and diffusion of gaseous molecules. In addition, the amplified fluorescence quenching induced by the enhanced intermolecular exciton diffusion along the long axis of the 1D nanostructures is another reason for the high performance of the obtained sensory nanomaterial.

A series of molecular salts of trans-4,4′-stilbenedicarboxylic acid (H2SDC) with various amines (cyclohexylamine 1, ethylenediamine 2, 1,3-diaminopropane 3, 1,4-diaminobutane 4, cystamine 5, guanidine 6, 4-aminopyridine 7, piperizine 8) have been synthesized and their structures have been determined by X-ray crystallography to understand the influence of various dominant non-covalent interactions in their crystal packing to attain energy minima in the solid state architectures. The well-defined patterns of these interactions have been analysed to assign the corresponding graph set notations and the concept of ‘supramolecular synthon’ has been justified. The presence of olefinic double bond and its orientations in these molecular salts make it interesting to study their photoreactivity towards UV light for [2 + 2] cycloaddition reaction. In the salt of 1,3-diaminopropane, the dianion was found to align perfectly parallel, congenial for solid state [2 + 2] cycloaddition reaction, undergoing quantitative dimerization under a UV lamp. Although the dianion was found to align perfectly parallel in salt 1, the photostability of this salt justifies Schmidt's distance criterion. The slip-stacked orientation of the dianion makes the molecular salt 4 photostable. A zigzag water cluster chain stabilised by various H-bonding interactions was identified in the molecular salt 6. The photoreactivity of the salts with 3,3′-dipropylamino amine 9 and with ammonia 10 are also accounted to discuss the possible relation between the chain length of the dications.

YESILEL, Okan Zafer/0000-0002-2284-1578 WOS: 000287458500013 Three novel cadmium(II) complexes containing orotate ligand have been synthesized under different pH and characterized by X-ray crystallography, IR spectroscopy and thermal analyses measurements. In the complexes, the orotate ligand exhibits three different coordination modes. In [Cd-2(mu-HOr)(2)(H2O)(4)(NH3)(2)]center dot 2H(2)O (1), the orotate acts as a tridentate ligand, showing unprecedented coordination mode. The (NH4)(2)[Cd-3(mu-HOr)(2)(HOr)(2)(H2O)(8)]center dot 4H(2)O (2) is constructed from orotate acting as both bidentate and tridentate bridging ligands. The Cd1 and Cd2 ions have two different coordination environments with four HOr, eight aqua ligands. Furthermore, 2 exhibits the novel 2D metal-water cluster layers. The (Hcha)(4)[Cd(HOr)(2)(H2O)(cha)][Cd(HOr)(2)(H2O)(2)]center dot H2O (3) (cha cyclohexylamine, H(3)Or = orotic acid) consists of discrete cis and trans anionic complexes. The cha molecules exhibit chemically different functions by coordinating to Cd(II) ion in one form and being protonated and acting as counter-ions in other form. In the complexes, the supramolecular networks are constructed by novel N-H center dot center dot center dot O strong hydrogen bonds to form DA : AD motif, C=O center dot center dot center dot pi and pi center dot center dot center dot pi interactions. Eskisehir Osmangazi UniversityEskisehir Osmangazi University [200819042] This work was supported by the Eskisehir Osmangazi University by project no. 200819042.

The potential of the heteroleptic heavier alkaline-earth hexamethyldisilazides [{HC(C(Me)2N-2,6-iPr2C6H3)2}Ae{N(SiMe3)2}(THF)] (Ae = Ca, Sr, Ba) as kinetically-stable reagents for further protolytic reaction chemistry has been assessed. Only the previously reported calcium complex was found to be stable to solution dismutation and dynamic ligand exchange. The barium complex was isolated in sufficient purity to enable characterisation by an X-ray analysis. Reactions of the kinetically robust calcium complex with cyclohexylamine and tert-butylamine resulted in displacement of THF and formation of solvated structures, which could be characterised by 1H NMR spectroscopy. Attempts to isolate these solvated complexes were unsuccessful due to redistribution to the homoleptic complex [{HC(C(Me)2N-2,6-iPr2C6H3)2}2Ca]. In contrast, the more acidic amine [H2NCH2CH2OMe] was cleanly deprotonated resulting in the isolation of the first well defined primary amido derivative of a heavier alkaline-earth element, [{HC(C(Me)2N-2,6-iPr2C6H3)2}Ca{NHCH2CH2OMe}]2, which retains its dimeric constitution in solution and is stable to further intermolecular ligand exchange. Reactions of [{HC(C(Me)2N-2,6-iPr2C6H3)2}Ca{N(SiMe3)2}(THF)] with a variety of ortho-disubstituted anilines also resulted in immediate protonation of the hexamethyldisilazide ligand. Only the most sterically demanding 2,6-diisopropylphenyl anilide derivative possessed sufficient kinetic stability to allow isolation of the heteroleptic complex. The crystal structure of [{HC(C(Me)2N-2,6-iPr2C6H3)2}Ca{N(H)-2,6-iPrC6H3}(THF)] was shown to exist as a mononuclear, pseudo-five-coordinate complex in which the coordinative unsaturation of the calcium centre is relieved by a Ca⋯H–C agostic-type interaction to one of the ortho isopropyl groups of the anilide ligand. This interaction is not maintained in solution however and the complex slowly redistributes to the homoleptic β-diketiminato species and ill-defined polymeric calcium anilido products.

This paper describes a flow-injection (FI) method for the simultaneous determination of aniline and cyclohexylamine impurities in cyclamate products. The method consists of the derivatization of amines with 1,2-naphthoquinone-4-sulfonate under selective and non-selective conditions. Here, the selectivity is achieved by working at 20 degree C, at which only aniline reacts, whilst higher temperatures (80 degree C) lead to a non-selective reaction of the two analytes. The FI manifold is composed of two flow cells for the spectrophotometric detection of derivatives at 480 nm. Experimental conditions have been optimized by factorial design and multicriteria making approach. Quantification is accomplished by differential analysis of the analyte contributions in the double peaks generated when the sample reaches cell 1 and cell 2. Results obtained with the proposed method are in satisfactory agreement with those provided by the standard method for the analysis of cyclamate samples.

Ni2+- and Al3+-exchanged montmorillonite are known to demonstrate Lewis and Bronsted acidity, respectively, when probed using the diagnostic base pyridine (C. Breen, Clay Miner., 1991, 26, 487). Thermogravimetric analysis (TGA) of pyridine saturated Al3+- and Ni2+-montmorillonite differ whereas here it was found that cyclohexylamine (CHA) desorption profiles were very similar, albeit CHA was held to a higher temperature on Ni2+-SWy-2 than on Al3+-SWy-2. Evolved gas analysis (EGA) of the desorbed products revealed significant differences in the amount of cyclohexylamine, cyclohexene, methylcyclopentene, benzene and aniline produced, which demonstrated different decomposition pathways for CHA sorbed to Al3+- and Ni2+-exchanged SWy-2. For example, cyclohexene is produced over both exchange forms whereas aniline and methylcyclopentene were the major products over Ni2+- and Al3+-SWy-2, respectively. Variable-temperature DRIFTS was unable to distinguish between CHA-treated Al3+- and Ni2+-SWy-2 at temperatures

A zinc chlorophosphate, of the composition [C6NH14][ZnCl(HPO4)], with a layered architecture has been synthesized, for the first time, in the presence of cyclohexylamine as the structure-directing agent. The structure comprises a network of ZnO3Cl and PO4 tetrahedra forming macroanionic layers with four- and eight-membered apertures. Charge compensation is achieved by the protonated amine occupying inter-lamellar space and interacts with the framework via hydrogen bonding. The crystal structure of the new compound was determined.

A flow injection spectrophotometric method for the simultaneous determination of aniline and cyclohexylamine using multivariate calibration methods is proposed. The method is based on the reaction of these amines with 1,2-naphthoquinone-4-sulfonate, yielding spectrophotometrically active derivatives. The data analysed with multivariate calibration methods consisted of the spectra registered in the range 290–590 nm at the maximum of the flow injection peak. Although the spectrum of each derivative was characteristic, overlapping occurred and no selective wavelengths were found. The predictive abilities of principal component regression and partial least-squares regression (PLS), non-linear PLS, locally weighted regression (LWR) and artificial neural networks were examined for the determination of aniline and cyclohexylamine in sample mixtures. The accuracy for cyclohexylamine and aniline quantifications in unknown mixtures was optimum with LWR, providing overall prediction errors of 3.4 and 5.6%, respectively.

An organometallic non-aqueous route to zinc phosphonates and to their intercalates has been studied. Various phosphonic acids react with dimethylzinc in THF media to afford the corresponding layered zinc phosphonates Zn(O 3 PR 1 ) (R 1 = Me, Ph, 2- and 3-thienyl, thiophen-3-ylmethyl) with evolution of methane. The presence of a primary n-alkylamine in the reaction mixture allows the one-pot formation of 2D-layered intercalated phases of general formula Zn(O 3 PR 1 )·RNH 2 [R 2 = Bu n , Pen n (= n-pentyl)] whereas a more bulky amine such as cyclohexylamine (Hex c NH 2 ) lead to the formation of 1D polymeric chains of formula Zn(O 3 PPh)·2Hex c NH 2 .

A highly crystalline compound Hf(PO4)(H2PO4)·2H2O (γ-HfP) has been prepared via the partially substituted γ-HfP sodium phase, by the reflux method. Its crystalline structure was solved by X-ray powder diffractometry: monoclinic, space group P21, a = 5.3499(3), b = 6.5949(4), c = 12.3939(8) A, β = 98.594(5)° and Z = 2. The final agreement factors are: Rwp = 0.054, Rexp = 0.031 and RF = 0.033. The compound is isostructural with γ-ZrP and has a layered structure built from PO4 tetrahedra and HfO6 octahedra stacked along the [001] direction. Its intercalation behaviour with n-alkylamines (n = 1–6) and cyclic amines (aniline, benzylamine, cyclohexylamine, piperidine and pyridine) was studied. The intercalation solids obtained present expanded interlayer distances and a general composition Hf(PO4)(H2PO4)·xamine·H2O where x varies from 0.8 to 2.

An acid-activated saponite has been used in the preparation of Al and Zr pillared acid-activated clays. The properties of this new family of pillared clays (pillared acid-activated saponites, PAASs) have been compared to those of conventional pillared (non-activated) saponites (PILSs). It is found that the acid treated materials incorporate less Al or Zr than the parent saponite, with the most likely cause being the reduced cation exchange capacity of the matrix following acid-activation. Powder X-ray diffraction suggests that Al PAASs are thermally more stable than the corresponding Zr PAASs. The acidity of the pillared materials (as monitored by cyclohexylamine adsorption–desorption thermogravimetry studies) is related to the nature and to the amount of the metal oxides incorporated between the sheets of the host clays. Catalytic data for the Bronsted catalysed dehydration ofpentan-1-ol is reported.

Reactions between 9-methylxanthine (9-mxan) and platinum(IV) complexes having ammine, organic amine and chloro ligands are speeded up dramatically by additions of small amounts of the analogous platinum(II) complex. Complexes studied include cis-dichlorodiammineplatinum(II) {cis-[Pt(NH3)2Cl2] 1a}, cis-tetrachlorodiammineplatinum(IV) {cis-[Pt(NH3)2Cl4] 1b}, cis-dichloroammine(cyclohexylamine)platinum(II) {cis-[Pt(NH3)(cha)Cl2] 2a}, cis-tetrachloroammine(cyclohexylamine)platinum(IV) {cis-[Pt(NH3)(cha)Cl4] 2b}, chloro(diethylenetriamine)platinum(II) chloride {[Pt(dien)Cl]Cl 3a} and mer-trichloro(diethylenetriamine)platinum(IV) chloride {mer-[Pt(dien)Cl3]Cl 3b}. For a 10∶90 molar ratio of 1a∶1b, the half-life for platinum(IV)–9-mxan product formation is approximately 3 h whereas t½ for pure 1b–9-mxan product formation is greater than 90 h, indicating a 30 times rate enhancement upon addition of 10% of the platinum(II) complex. For the 2a∶2b pair, an eight-fold rate enhancement is observed over that for pure 2b–9-mxan. This behavior may be related to the chloride bridging mechanism first elucidated for platinum-(II) and -(IV) complexes. Since known platinum-(II) and -(IV) antitumor drugs target nucleobases of DNA to effect cell death in malignant cells, the reactions discussed may shed light on platinum antitumor compound reaction mechanisms.

Titanium pillared clays using montmorillonite, saponite and rectorite hosts have been prepared from TiCl 4 –ethanol solutions. The products have been characterised structurally by PXRD and IR studies and for acidity by cyclohexylamine and pyridine adsorption–desorption studies. Catalytic activity data for pentanol dehydration and cumene cracking are also presented. The amount of Ti incorporated is related to the cation-exchange capacity of the host. The thermal stability of the pillared material decreases from rectorite through montmorillonite to saponite. Cyclohexylamine desorption suggests that the saponite sample has the highest acidity, and this is reflected in the highest conversion for cumene cracking. In the case of pentanol dehydration, however, the highest activity is seen for the rectorite sample, despite its apparent lower acidity. Similar effects have been reported previously for this reaction with alumina pillared clays.

XRD, FTIR spectroscopy, cyclohexylamine desorption, potentiometric titrations and catalytic activity in an ether-forming test reaction have been used to investigate mildly acid-treated montmorillonite (SAz-1) and hectorite. The number of acid sites obtained from the cyclohexylamine desorption agreed with the accepted cation exchange capacity values for all samples. No evidence of any free protons was found in the potentiometric titration curves, which proved that complete autotransformation of the acid-treated samples had occurred over a much shorter period than previously recorded. Acid sites associated with Al3+ (Fe3+) released from the SAz-1 structure during acid treatment and subsequent autotransformation were of sufficient strength to catalyse the test reaction and produce tetrahydropyranyl ether in 80% yield. The complete absence of catalytic activity in the acid-treated hectorite samples confirmed that acid sites associated with interlayer Mg2+ and Li+ were unable to catalyse the test reaction.

The < 2 µm fractions of Cheto (Arizona, USA) and Jelsový Potok (Slovakia) montmorillonites have been treated with 1 mol dm–3 H2SO4 for periods up to 6 h at 95 °C. The materials obtained were investigated by X-ray fluorescence (XRF), X-ray diffraction (XRD), infrared (IR) spectroscopy, and 29Si and 27Al magic-angle spinning (MAS) NMR spectroscopy. Both clays were partially decomposed under the conditions utilized, but the Cheto montmorillonite, which contained a higher proportion of octahedral magnesium, was more susceptible to acid attack. XRD was insensitive to this level of acid attack but XRF, IR and 29Si MAS NMR revealed the depopulation of the octahedral sheet. The number of acid sites was determined from the thermal desorption of cyclohexylamine and the catalytic activity was evaluated by reacting 2,3-dihydropyran with methanol to yield the tetrahydropyranyl ether. The test reaction was a more sensitive indicator of changes in clay acidity than the values determined by desorption of cyclohexylamine from acid sites.

The reaction of 2, 6-dinitroanisole with cyclohexylamine in toluene, octanol and toluene–octanol mixtures has been studied at several amine concentrations. The reactions in toluene and in octanol–toluene mixtures up to 30% octanol show a third-order kinetic dependence on [amine]. Although the reaction rates in toluene and octanol are very similar, addition of small amounts of octanol to the toluene solution diminishes the rate of reaction, reaching a minimum value at 30–50% octanol, after which the rate increases almost linearly with the octanol content. These and other results, here described, are satisfactorily explained by the previously proposed ‘dimer nucleophile mechanism’. Previously reported similar observations in methanol–benzene mixtures were criticised as being due to the reversibility of the reaction. The present results confirm the previously reported mechanism and the irreversibility of the reaction under the reaction conditions.

t-Butyl hydroxy{4-[(Z)-2-(methoxycarbonyl)vinylthio]-2-oxoazetidin-1-yl}acetate (19a) was transformed into t-butyl 2-endo-methoxycarbonylmethyl-3-thiacepham-4-exo-carboxylate (20a) by sequential reactions involving thionyl chloride, potassium thioacetate, and cyclohexylamine. Oxidation of compound (20a) with potassium permanganate gave the 1,1,3,3-tetraoxide (23a), the structure of which was established by X-ray crystallography. The exceptional acidity of the 2- and 4-hydrogen atoms of compound (23a) was revealed by their replacement with deuterium atoms in the presence of deuterium oxide and with methyl groups in the presence of diazomethane. Cleavage of the t-butyl ester function of the thiacepham tetraoxide (23a) was effected by trifluoroacetic acid but the resultant acid (23b) underwent a rapid decarboxylation in water to give 2-endo-methoxycarbonylmethyl-3-thiacepham 1,1,3,3-tetraoxide (26a).

The reaction of 2,4-dinitrofluorobenzene (DNF) with aniline in toluene and in chloroform at 35 °C shows a third-order kinetic dependence on [amine]. In hydrogen-bond acceptor (HBA) solvents, an important rate increase, and a second-order dependence on [amine], are observed. Finally, the reaction shows a second-order dependence on non-nucleophilic tertiary amines. All these results are fully consistent with the previously proposed ‘dioner nucleophile mechanism.’Another approach towards confirming the mechanism was designed: a system where an ‘intramolecular dimer nucleophile’ is possible. The reactions of DNF with cyclohexylamine, and with cis-and trans-1,2-diaminocyclohexane, were studied in toluene, and also in toluene–methanol mixtures in some cases. The kinetic order observed, as well as the enhanced reactivity of the cis isomer and the solvent effects are new evidence in favour of the ‘dimer nucleophile’ mechanism. The results cannot be explained by other, alternative mechanisms.

The binding of the substrates cis-[Co(en)2BCl]2+(en = 1,2-diaminoethane, B = alkylamines, imidazole, N-methylimidazole) to the micellar surface of sodium dodecyl sulphate resulted in the retardation of their dissociative aquation rates, the effect being sensitive to the hydrophobicity of the nonlabile amine ligand B. A contrastingly small rate acceleration for the corresponding ethanolamine and propan-2-ol amine complexes was observed under similar conditions. Triton X-100 (0.02 ⩽[Triton X]T/mol dm–3⩽ 0.1) had virtually no effect on the aquation rates of such complexes except for cis-[Co(en)2(C6H11NH2)Cl]2+, in which case a small rate retardation was also observed. The rates of base hydrolysis of the cobalt(III) substrates were strongly retarded by the anionic micelles of SDS; the neutral micelles of Triton X-100 were effective in decelerating the rate of base hydrolysis of the cyclohexylamine complex cis-[Co(en)2(C6H11NH2)Cl]2+ only. The pseudo-phase ion-exchange equilibrium model satisfactorily explained the binding of the cationic substrates to the anionic micellar pseudo-phase of SDS. The values of the ion-exchange equilibrium constant and the relative base hydrolysis rates (kW/kM) indicated that both micellar binding and retardation of hydrolysis are governed by hydrophobic and electrostatic interactions.

The influence of arylthiols on cysteine-free ligation, i.e. the reaction between an alkyl thioester and a primary amine forming an amide bond, was studied in a polar aprotic solvent. We reacted the ethylthioester of hippuric acid with cyclohexylamine in the absence or presence of various quantities of thiophenol (PhSH) in a slurry of disodium hydrogen phosphate in dry DMF. Quantitative conversions into the resulting amide were observed within a few hours in the presence of equimolar amounts of thiophenol. Ab initio calculations showed that the reaction mechanism in DMF is similar to the well-known aqueous reaction mechanism. The energy barrier of the catalyzed amidation reaction is approximately 40 kJ mol(-1) lower than the non-catalyzed amidation reaction. At least partially this can be explained by a hydrogen bond from the amine to the π-electrons of the thiophenol, stabilizing the transition state in the aromatic thioester amidation reaction. Under similar conditions, cysteine-free ligation was achieved by coupling a fully side-chain protected 15 amino acid phosphopeptide thioester to the free N-terminal of a side-chain protected 9 amino acid peptide producing the corresponding 24 amino acid phosphopeptide.

The interzeolite conversion of zeolite MCM-49 into zeolite ZSM-35 in “cyclohexylamine (CHA)–hexamethyleneimine (HMI)–Na2O–H2O” systems, consisting of “CHA–Na2O–H2O”, “HMI–Na2O–H2O” and “Na2O–H2O”, was investigated in detail using X-ray diffraction (XRD), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR) characterization techniques. Both CHA and HMI play important roles in directing the interzeolite conversion of MCM-49 into ZSM-35, and the conversion speed is much faster in systems containing CHA than those containing HMI. Even in the Na2O–H2O system without any organic amine, MCM-49 can still transform into some other zeolites with more stable topological structures than itself, such as ZSM-35, ZSM-5, and mordenite, but the product of the interzeolite conversion is more complicated than that in the systems containing organic amines (CHA and/or HMI). In the Na2O–H2O system, alkalinity has been proved to be a crucial factor influencing the conversion trend of MCM-49. Zeolites ZSM-5 and mordenite will appear in the products besides ZSM-35 with the increase of the alkalinity. The conversion process of zeolite MCM-49 in the systems investigated accords well with the solution-mediated transformation mechanism.

The salts formed between racemic 1,1′-binaphthyl-2,2′-dicarboxylic acid (BNDA) and the amines diethylamine (DEA), di-n-butylamine (DBA), cyclohexylamine (CHA) and dicyclohexylamine (DCHA) are reported. Structure 1, (BNDA2−)(2DEA+), and 2a, (BNDA2−)(2DBA+), resulted from slow evaporation of a solution of BNDA in the respective amine. A competition experiment whereby BNDA was dissolved in a mixture of 60% DEA and 40% DBA resulted in a polymorph of 2a, namely 2b. Slow evaporation of dilute solutions of BNDA with CHA and DCHA resulted in a mixed salt solvate 3, (BNDA2−)(3CHA+)(C7NO2H11−)·CHA·H2O, and a salt solvate, 4, (BNDA2−)(2DCHA+)·CH3OH·H2O, respectively. For all the experiments methanol was used as a co-solvent due to BNDA insolubility with the amines. In structure 3 one of the CHA guests reacted with carbon dioxide in the atmosphere to form a carbamate anion, C7NO2H11−. The kinetics of desolvation for salts 1, 2a and 2b were also determined.

At ambient temperature, with various mono(di)protonated N-heterocyclic or diamine molecules as the cations, seven new halo(pseudohalo)cadmates [H2(bpee)][Cd(SCN)4] (bpee = 1,2-bis(4-pyridyl)ethene) 1, [H2(bpyp)][CdBr2(SCN)2] (bpyp = 1,2-bis(4-pyridyl)propane) 2, [H2(mbcha)][Cd3Br2(SCN)6] (mbcha = 4,4′-methylenebis(cyclohexylamine)) 3, [(Hdabco)2Cd3(SCN)8] (dabco = 1,4-diazabicyclo[2,2,2]octane) 4, [H2(bp)][Cd(SeCN)4] (bp = 4,4′-bipiperidine) 5 [H2(pdma)][Cd(SeCN)4]·2H2O (pdma = 1,4-phenylenedimethanamine) 6 and [H2(4,4′-dtdpy)][Cd2Br6] (dtdpy = dithioidipyridine) 7 were obtained. X-ray analysis revealed that (i) compound 1 possesses a three-dimensional (3D) supramolecular network structure with the one-dimensional (1D) channels, constructed from the inorganic [Cd(SCN)4]2− chains by weak S⋯S interactions. The H2(bpee)2+ molecules occupy the space of the channels; (ii) with H2(mbcha)2+ as the cation, the anion [Cd3Br2(SCN)6]2− of compound 3 exhibits a 1D ribbon structure, which can be described as a lengthways packing of planar bi-bridged trimers; (iii) compound 4 is the first example of the cation-controlled 3D thiocyanatocadmate with a composition [Cd3(SCN)8]2−; (iv) with H2(4,4′-dtdpy)2+ as the cation, the anion [Cd2Br6]2− of compound 7 also shows a 1D ribbon structure. This ribbon can be described as a transverse stacking of two planar bi-bridged single chains; (v) the ribbons of compounds 3 and 7 can be visualized as a slice of the two dimensional (2D) CdX2 layer; (vi) in compounds 2, 3, 5, 6 and 7, the organic molecules as the linkers extend the inorganic anionic moieties into various 2D supramolecular layer networks.

Porous ZnO nanotubes with superior sensing response to ethanol have been prepared by simple thermal treatment of an inorganic–organic ZnS–CHA (CHA = cyclohexylamine) hybrid precursor.

The efficient and atom economical synthesis of 5-membered cyclic structures has been achieved through the combination of amino catalysis and metal catalysis. The discovery of a novel metallo-organocatalytic system merging the use of a catalytic copper(I) complex and a catalytic amount of cyclohexylamine allowed the room temperature preparation of a broad range of skeletons such as cyclopentanes, indanes, pyrrolidines and tetrahydrofuran, important structural cores of many biologically relevant molecules. Mechanistic studies were presented.

This perspective article discusses developments of metal-free hydrogenation catalysts derived from "frustrated Lewis pair" (FLP) systems. The range of catalysts uncovered and the applications to reductions of imines, aziridines, enamines, silyl enol ethers, diimines, metallocene derivatives and nitrogen-based heterocycles are described. In addition, FLP aromatic reduction of aniline derivatives to the cyclohexylamine analogs is discussed. The potential applications of these metal-free reductions are considered.

The synthesis of disubstituted ureas from amines and CO2 were carried out using a basic ionic liquid (IL) 1-n-butyl-3-methyl imidazolium hydroxide ([Bmim]OH) as the catalyst. The effects of reaction time, amount of [Bmim]OH, reaction temperature, pressure, and solvent on yields of the products were investigated. The results indicated that aliphatic amines, cyclohexylamine, and benzylamine could be converted to the corresponding ureas selectively in moderate yields under solvent-free conditions without using any dehydrating regent. The IL could be reused after a simple separation procedure.

A novel aluminophosphate microporous compound, denoted UHM-5, synthesized from an aqueous aluminophosphate gel at 150 °C in the presence of cyclohexylamine as the template, transforms upon calcination above 300 °C into AlPO4-5 molecular sieve.

The synthesis and single-crystal X-ray structure of ULM-16, a new fluorinated gallophosphate Ga4(PO4)4F2·1.5NC6H14·0.5H2O·0.5H3O is described. This material is prepared hydrothermally at 180 °C using cyclohexylamine as structuring agent. It crystallizes in the orthorhombic space group Pbcn(no. 60) with a= 27.329(4), b= 17.377(2), c= 10.2124(5)A, V= 4849.6(9)A3 and Z= 8, with R= 0.0477 for 3006 observed reflections [I > 2σ(I)]. The structure is built up from vertex-linked GaO4 and PO4 tetrahedra, GaO4F trigonal bipyramids and GaO4F2 octahedra forming hexameric and tetrameric units. The three-dimensional framework consists of one-dimensional circular tunnels delimited by sixteen polyhedra and is stable up to 800 °C.

A novel concept of base proliferation for improving the photosensitivity of base-sensitive materials is described by presenting the autocatalytic transformation of 9-fluorenylmethyl carbamates to aliphatic amines. A 9-fluorenylmethyl carbamate, as a base amplifier, was subjected to a base-catalysed fragmentation reaction to liberate the corresponding amine, which can then act as a catalyst for decomposing parent molecules, leading to autocatalytic decomposition. Consequently, the amine is generated from an equimolar amount of the carbamate using a catalytic amount of the same amine. 1-(9-Fluorenylmethoxycarbonyl)piperidine and 1-(9-fluorenylmethoxycarbonyl)cyclohexylamine were suitable as base amplifiers because of their thermal stability under neutral conditions and high base-catalytic reactivity. On the basis of the results, 1,3-bis[1-(9-fluorenylmethoxycarbonyl)-4-piperidyl]propane and 1,6-bis[(9-fluorenylmethoxy)carbonylamino]hexane were designed as base amplifiers which liberate aliphatic diamines to crosslink poly(glycidyl methacrylate) photochemically in the presence of a photobase generator. Addition of the base amplifiers resulted in a marked improvement of the photosensitivity characteristics of the polymer by a factor of 16 and 50, respectively.

The intercalation behaviour from the liquid phase of n-alkylamines (n = 1–6) and the cyclic amines aniline, benzylamine, cyclohexylamine, piperidine and pyridine in α-hafnium phosphate Hf(HPO 4 ) 2 ·H 2 O has been studied. The composition of the intercalation compounds was determined and the arrangement of the amines in the interlayer region as mono-(pyridine) or bi-molecular films (the remaining amines) is discussed from data obtained from X-ray diffraction, IR spectroscopy and chemical and thermal analysis.

Reaction of the chlorophosphite Cl[graphic omitted] 1 with cyclohexylamine gave the expected product (C6H11NH)[graphic omitted] 3 whereas the corresponding chloroarsenite 2 led to the bridged compound 12. When the reaction was performed in the presence of water, 1 gave the expected product H(O)[graphic omitted] 11 whereas 2 gave the oxo-bridged compound ([graphic omitted])2O 13. The amino phosphite 3 underwent hydrolysis to afford the ring cleaved product 18 whereas the phenoxy phosphite 21 led to the ring preserved compound 11. In contrast, the corresponding phenoxy arsenite (PhO)[graphic omitted] 25 gave the oxo-bridged compound 13. Addition of perchloro-o-benzoquinone to the phosphite 23 was highly exothermic and afforded the phosphorane 29; however the corresponding arsenonate 27 reacted very sluggishly at room temperature and when heated gave an uncharacterizable mixture of products.The identity of the title oxy-bridged compounds 13 and 15 obtained here has been confirmed by X-ray structure determination; the six-membered rings in 13 have a ‘chair’ conformation and the eight-membered rings in 15 have a ‘symmetrical anti’ conformation.

The step-polymerization reaction between monoamines and diepoxide has been investigated by measuring the permittivity and dielectric loss as a function of reaction time, tre, at different temperatures. Hexylamine and cyclohexylamine were used both in stoichiometric and non-stolichiometric (amine-rich) compositions with the diglycidyl ether of bisphenol-A. The dielectric consequences of increase in the growth of the macromolecule during the step-polymerization are analogous to the frequency dependence of a chemically invariant substances. The reaction-time dependence of Iµ* has the functional form: Φ(t)= exp –[t/τ(tre)]γ where γ= 0.3–0.4. Steric hindrance of the NH2 group in cyclohexylamine slowed the rate of polymerization and the Iµ* features were shifted towards longer tre. Excess amine accelerated the polymerization process, but shifted the dielectric features towards longer reaction time. Although the reaction reached completion, the mixture did not vitrify. In this respect the dielectric behaviour differs from that of network polymerization. Reaction temperature, time, composition and chemical structure of the monoamine, all affected the strength of the sub-glass transition temperature (Tg) relaxations of the polymerized product.

Co K-edge EXAFS data of some (porphinato)cobalt(III) complexes with amine ligands in chloroform solution are reported. Data for the following compounds were collected: chloro(tetraphenylporphinato)cobalt(III)(TPPCoCl) complexed with pyridine (A), isoquinoline (B) and cyclohexylamine (C) and 4-methylpiperidine complexed with the sterically hindered chloro(tetra-o-dichlorophenylporphinato)cobalt(III)(TCIPCoCI)(D) and chloro(tetra-o-difluorophenylporphinato)cobalt(III)(TFPCoCl)(E). In addition to the four N atoms from the macrocyclic porphyrin ligand, the cobalt atom is coordinated to either one amine and a chlorine atom (A and B) or two axial amine ligands with the chloride as a counterion (C–E). An interesting feature is the longer Co—Cl distances in A and B relative to those in the solid state. The Co—N distances are represented by a single composite distance ranging from 1.91(1) to 1.95(1)A. The Co—N bond lengths for the ortho-substituted porphyrins were found to be similar to those in the less hindered TPP complexes. The EXAFS for the cobalt(II) compounds TCIPCo (F) and TFPCo (G) gave distances similar to those of the crystal structure of TPPCo. The equatorial Co—N distances depend more on the conformation of the porphyrin core than on the cobalt oxidation state, as demonstrated by the similarity between the CoIII—N and CoII—N distances.

Metallomacrocyclic compounds, such as metalloporphyrins, have been shown to catalyse the oxidative carbonylation of amines to carbamates which are precursors to isocyanates.