1-Methylnaphthalene complexes

Complexation with polyaromatic systems has also been observed. For instance, Mlnaphthalenelj, M = Cr (88,183), Mo (183), V (183), or Ti (183) may be synthesized in a solution reactor with the appropriate, metal vapors at liquid-nitrogen temperature. The Cr/naphthalene complex is less stable (dec. 160°C) than CrtCsH ) (m.p. 283-284° C). In fact, the naphthalene ligand is sufficiently labile to allow reaction under mild conditions, to afford CrL (L = CO or Bu NC), or Cr(naphth)Ls [L = PFj, P(OMe)3, or PMea]. The Mo, V, and Ti species are equally reactive. Analogous 1-methylnaphthalene complexes were also isolated (183). In addition, the complexes shown in Fig. 38 were synthesized by reaction, at the temperature of liquid nitrogen, of Cr atoms with 1,4-diphenylbutane (35, 201, 202). Analogous complexes were formed with 1,5-diphenylbutane (202). 

TMA quenched the naphthalene fluorescence in water with the quenching rate constant (k ) of 1 x 10 M s Of course, no exciplex emission was observed in the aqueous solution. In the presence of 1 x 10 M g-CD, however, the exciplex emission having a maximum intensity at kll nm was clearly observed as shown in Fig. 1. Virtually the same results were obtained for the 1-methylnaphthalene-TMA system. Since the B-CD-1-methylnaphthalene complex precipitated in the 1x10 M g-CD solution, g-CD-2 was used in place of g-CD. The k value was 6.2 x 10 M s and no exciplex emission was observed in the aqueous solution without g-CD-2. In the presence of g-CD-2 (1 x 10 M), a broad exciplex emission having a at 4 73 nm was measured. A relatively weak fluorescence band of exciplex of acenaph-thene and TMA was observed at around U50 nm in the 1.0 x 10 M g-CD solution. 

Salts of diazonium ions with certain arenesulfonate ions also have a relatively high stability in the solid state. They are also used for inhibiting the decomposition of diazonium ions in solution. The most recent experimental data (Roller and Zollinger, 1970 Kampar et al., 1977) point to the formation of molecular complexes of the diazonium ions with the arenesulfonates rather than to diazosulfonates (ArN2 —0S02Ar ) as previously thought. For a diazonium ion in acetic acid/water (4 1) solutions of naphthalene derivatives, the complex equilibrium constants are found to increase in the order naphthalene < 1-methylnaphthalene < naphthalene-1-sulfonic acid < 1-naphthylmethanesulfonic acid. The sequence reflects the combined effects of the electron donor properties of these compounds and the Coulomb attraction between the diazonium cation and the sulfonate anions (where present). Arenediazonium salt solutions are also stabilized by crown ethers (see Sec. 11.2). 

Dehydrogenation (the conversion of alicycllc or hydroaromatic compounds into their aromatic counterparts by removal of hydrogen and also, in some cases, of other atoms or groups) finds wide application in the determination of structure of natural products of complex hydroaromatic structure. Dehydrogenation is employed also for the s)mthesis of polycyclic hydrocarbons and their derivatives from the readily accessible synthetic hydroaromatic compounds. A very simple example is the formation of p-methylnaphthalene from a-tetra-lone (which is itself prepared from benzene—see Section IV, 143) ... 

Boron trifluoride complexes are also often applied. BF3 when used with acyl fluorides showed in some cases distinct differences compared to other catalyst-reagent combinations. For example, acylation of 2-methylnaphthalene with isoBuCOF and BF3 gives high yield (83%) of the 6-substituted isomer in contrast to AICI3 (30%).40 A similar example is shown here ... 

Dimercury(I) n complexes are formed between aromatic compounds and Hg2(AsF6)2 in liquid S02 as solvent.113,121 Insoluble complexes with the ratio arene Hg2+ = 1 1 (arene = benzene, naphthalene, 2-methylnaphthalene, 2,6-dimethylnaphthalene, acenaphthene, fluor-anthrene, phenanthrene, anthracene, 9,10-dimethylanthracene or 1,3-dinitrobenzene) or 1 2 (arene = 9,10-benzophenanthrene) have been characterized by elemental analysis and, in some cases, by Raman spectrometry.113,120 The 13CNMR data allow the estimation of formation constants for the hexamethylbenzene, p-xylene and 1,4-dichlorobenzene complexes together with the chemical shifts for the bound substrates in these cases.121 Probably the coordination compounds of dimercury(I) salts with carbazole, dibenzofuran and diben-zothiophene are also n complexes.122... 

The cerium(IV) oxidation of lactyllactic acid49 and of 4-oxopentanoic acid50 in aqueous nitric acid solutions shows first-order dependence of the reaction on both cerium(IV) and substrate. A 1 1 complex formation between manganese(III) and amine, which later decomposes in the rate-limiting step, best explains the kinetics of oxidation of aliphatic amines by cerium(IV) in nitric acid medium in the presence of manganese(II).51 The kinetics of oxidation of naphthalene, 2-methylnaphthalene, and a-naphthol with cerium(TV) in perchloric acid solutions have been studied.52 Use of a 50-fold molar excess of cerium(IV) perchlorate results in complete oxidation of fluorophenols to C02, HC02H, and HF in 48 h at 50 °C.53... 

McCullough and co-workers first reported the photocycloaddition of acrylonitrile (33a) to naphthalene in 1970 [94,95], They systematically investigated the photocycloaddition of 33a to mono- and di-methylnaphthalenes however, the yields and selectivity were not high and usually a complex mixture was produced [128] (Scheme 18). 

ArCH2COCH2Ar with the unstable a-derivative being possible intermediates. Naphthalene, a more flexible system, reacts in a rather surprising manner so that j8-methylnaphthalene yields the trimethylenemethane complex (XXI) (438). 

The alkylation of the naphthenic cation causes formation of complex aliphatic carbonium ions. Transformation of such intermediates according to Poustma [30] gives the molecules of light saturated hydrocarbons and aromatics. It is generally accepted that the formation of condensed aromatic rings being a coke precursors is difficult in the pores of ZSM-5 zeolite. The fact that the products of the toluene transformation reaction in all cases contained 1 - and 2-methylnaphthalene seems to prove their formation from the olefinic or naphthenic carbocations. Transformation of the naphthenic carbocations occuring in zeolite pores and on the external zeolite surface is the most probable source of methyinaphthalene isomers [23]. 

Fig. 1 Gas chromatography-flame ionization detection chromatogram of a complex mixture of PAHs extracted by SFE from a contaminated soil. (1) naphthalene (2) 2-methylnaphthalene (3) 1-methylnaphthalene (4) acenaphthene (5) fluorene (6) dibenzothiophene (7) phenanthrene (8) anthracene (9) fluoranthene (10) pyrene (11) benzo(a)anthracene (12) chrysene (13) benzo(e)pyrene (14) benzo(a)pyrene (15) indeno(l,2,3-cd)pyrene (16) dibenzo(a,h)anthracene (17) benzo(g,h,i)perylene. (From Ref. [12].)...

In helium quantitative yield of HCI. remainder residue and hydrocarbons, benzene is major volatile hydrocarbons product aliphatic hydrocarbons, benzene (major product), toluene, ethylbenzene, o-xyiene, monochlorobenzene styrene, vinyl tcriuerre. p-dichlorobenzene, o-dichlorobenzene, indene, 1,3.5-trichlorobenzene 1.2.4. richlorobenzene. naphthalene, u-methylnaphthalene. p-methylnaphthatene effect of ZnO. SnOj, and Ab03 on the yields of products Is also recorded HCI. CO2. ethene. ethane, propane, 1-butene. 2-butene. 1-pentene. cydopentene, n-pentane, 2-methylbulane, 1,3-pentadiene. 2-methyl-1,3-pentadiene, complex series (60 Identlfled) of aromatic and polyaromatic species including benzene, styrene, methylstyrenes, toluene, o-xytene, m-xylene, p-xylene, biphenyl, naphthalene, anthracene, phenanthrene. pyrene, etc. 

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