Benzene-ammonia complex

The results on crystal structures are not the only experimental evidences of the existence of X-H- - - k interactions. There are numerous gas-phase experimental studies. For example, the high-resolution optical and microwave spectra on the benzene-ammonia complex were presented [9]. It was found that in the vibrationally averaged structure, the C3 symmetry axis of ammonia is tilted by approximately 58° relative to the Ce benzene axis. In such a way the N-H bonds interact with rr-electrons of benzene through N-H- - - k hydrogen bonds. The resonance-enhanced two-photon ionization, the microwave spectroscopy and the other spectroscopic techniques were used to analyze such complexes as C6H6-H2O [10], CeHe-HF [11], CeHs-HCl [12] and also T-shaped complexes where rr-electrons of acetylene act as the proton acceptor while such moieties as HF, HCl or HCN are the proton donors [13-15]. 

Spectroscopic measurements for the benzene-ammonia complex show that the ammonia molecule is positioned above the benzene plane and that the benzene acts as a proton acceptor [74]. The estimated interaction energy (Eq) from the experimental centrifugal distorsion constant is - 1.4 kcal/mol [74]. Very recently an Eq value of - 1.84 kcal/mol was reported [96]. The calculated AZPE is 0.6 kcal/mol, which implies that Ee lies between - 2.0 and - 2.4 kcal/mol [8]. 

Fig. 13 Orientation dependence of the interaction energy for the benzene-ammonia complex. mp2 is the total interaction energy. es is the electrostatic energy...

All coppei -nickel catalysts were prepared from the magnetically pure copper which was itself completely inactive in the hydrogenation of benzene under the conditions described below. Cupric hydroxide was precipitated from a nitrate solution by dilute ammonium hydroxide solution so that the supernatant liquid was faintly colored by the copper-ammonia complex. The precipitate was filtered and washed. Nickel nitrate in water solution was now added in the proportion desired, and the mixture was stirred to a paste of even consistency. It was dried at 95°, ignited at 180° for 36 hours, and finally at 400° for 20 hours. The oxide mixture was reduced in purified hydrogen at 150° for 20 hours. Most finished catalysts contained 1.0 per cent of nickel. 

C8H9CIN2O2, Benzenediazonium chloride - acetic acid, 33B, 243 C8HgN3Ni, Benzene-ammonia-nickel cyanide complex, 16, 521 C8H12N20ftS2f Cyclo-L-cystine - acetic acid, 40B, 546 C8H13N3O, 2,6-Lutidine-urea complex, 30B, 259... 

Fig.15 MP2/cc-pVTZ intermolecular interaction energies of the benzene-ammonia, benzene-water and benzene-methane complexes...

The covalent character of mercury compounds and the corresponding abiUty to complex with various organic compounds explains the unusually wide solubihty characteristics. Mercury compounds are soluble in alcohols, ethyl ether, benzene, and other organic solvents. Moreover, small amounts of chemicals such as amines, ammonia (qv), and ammonium acetate can have a profound solubilizing effect (see COORDINATION COMPOUNDS). The solubihty of mercury and a wide variety of mercury salts and complexes in water and aqueous electrolyte solutions has been well outlined (5). 

Bismuth ttiiodide may be prepared by beating stoichiometric quantities of the elements in a sealed tube. It undergoes considerable decomposition at 500°C and is almost completely decomposed at 700°C. However, it may be sublimed without decomposition at 3.3 kPa (25 mm Hg). Bismuth ttiiodide is essentially insoluble in cold water and is decomposed by hot water. It is soluble in Hquid ammonia forming a red triammine complex, absolute alcohol (3.5 g/100 g), benzene, toluene, and xylene. It dissolves in hydroiodic acid solutions from which hydrogen tetraiodobismuthate(Ill) [66214-37-7] HBil 4H2O, may be crystallized, and it dissolves in potassium iodide solutions to yield the red compound, potassium tetraiodobismuthate(Ill) [39775-75-2] KBil. Compounds of the type tripotassium bismuth hexaiodide [66214-36-6] K Bil, are also known. 

An even more effective homogeneous hydrogenation catalyst is the complex [RhClfPPhsfs] which permits rapid reduction of alkenes, alkynes and other unsaturated compounds in benzene solution at 25°C and 1 atm pressure (p. 1134). The Haber process, which uses iron metal catalysts for the direct synthesis of ammonia from nitrogen and hydrogen at high temperatures and pressures, is a further example (p. 421). 

Yosida et al. [41] found that p-t< rr-butylcalix[6]ar-ene can extract Cu from the alkaline-ammonia solution to the organic solvent. Nagasaki and Shinkai [42] described the synthesis of carboxyl, derivatives of calix-[n]arenes ( = 4 and 6) and their selective extraction capacity of transition metal cations from aqueous phase to the organic phase. Gutsche and Nam [43] have synthesized various substituted calix[n]arenes and examined the complexes of the p-bromo benzene sulfonate of p-(2-aminoethyl)calix[4]arene with Ni, Cu , Co-, and Fe. ... 

Lewis Bases. A variety of other ligands have been studied, but with only a few of the transition metals. There is still a lot of room for scoping work in this direction. Other reactant systems reported are ammoni a(2e), methanol (3h), and hydrogen sulfide(3b) with iron, and benzene with tungsten (Tf) and plati num(3a). In a qualitative sense all of these reactions appear to occur at, or near gas kinetic rates without distinct size selectivity. The ammonia chemisorbs on each collision with no size selective behavior. These complexes have lower ionization potential indicative of the donor type ligands. Saturation studies have indicated a variety of absorption sites on a single size cluster(51). 

Replacement of the hydroxyl group on the phenyl ring with a carboxyl group forms a molecule of benzoic acid. Addition of a hydroxyl at the 2-position on a benzoic acid molecule forms 2-hydroxybenzoic acid or salicylic acid. The slightly more complex phenylpropanoid skeleton contains a linear three-carbon chain (the propanoic group) added to the benzene ring (the phenyl group). Addition of ammonia to carbon 2 of this three-carbon side chain yields the amino acid phenylalanine (Fig. 3.3). Phenylalanine... 

Another example of an unusual reaction occurring in the gas phase is ammonia in a chromium complex ion being substituted by arenes such as benzene (4). It is important to note the uncommon oxidation state of the chromium. 

Carbazole will react with 1 or 2 mol of ferrocene in hot decalin in the presence of aluminium-aluminium chloride producing crystalline derivatives in which either one or both" of the benzene rings is linked to iron, 25 and 26, respectively. The sandwich compound 25 was deprotonated to 27 with sodamide in liquid ammonia. A chromium carbonyl complex 28... 

The reactions of chlorobenzene and benzaldehyde with ammonia over metal Y zeolites have been studied by a pulse technique. For aniline formation from the reaction of chlorobenzene and ammonia, the transition metal forms of Y zeolites show good activity, but alkali and alkaline earth metal forms do not. For CuY, the main products are aniline and benzene. The order of catalytic activity of the metal ions isCu> Ni > Zn> Cr> Co > Cd > Mn > Mg, Ca, Na 0. This order has no relation to the order of electrostatic potential or ionic radius, but is closely related to the order of electronegativity or ammine complex formation constant of metal cations. For benzonitrile formation from benzaldehyde and ammonia, every cation form of Y zeolite shows high activity. 

Mention may be made briefly of the studies of Malinovekii and ca-workers,1 . wiw.iw involving addition of ammonia to ethylene oxide, propylene oxide, and styrene oxide under stringent conditions. At 400-450° over an alumina catalyst, for example, ethylene oxide and ammonia are reported to give a moderate yield of pyridine (lfl.6-10.4%). With Btyrene oxide an exceedingly complex mixture of products is formed, among which are various pyrrole and pyridine derivatives, benzene, toluene, ethylbenzeno, benzoldehyde, acetophenone, phenylacetaldehyde, and others. 

The most interesting feature of this method, reviewed by Stepanov,62 is the ease with which the halogen atom is replaced by a hydroxyl group during the metallization process. This was first observed as long ago as 1931 when Delfs63 obtained the copper complex of 2-(2-hydroxy-naphthyl-l-azo)phenol-4-sulfonic acid (47) by heating an aqueous solution of l-chloro-2-(2-hydroxynaphthyl-l-azo)benzene-4-sulfonic acid (48), copper sulfate, sodium hydroxide and ammonia at 80 °C for 1 hour. 

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