C-H or C-C activation


Spontaneous Raman Spectroscopy. The Raman effect is the inelastic scattering of an incident photon to a new frequency DR = Di f mol, where is the energy acquired (—) or lost (+) by the molecule during a vibrational, rotational, or (less commonly) electronic transition. It is an important technique for the investigation of molecular stmcture, providing information similar, and often complementary, to ir spectroscopy, and for chemical analysis, both in the laboratory (40—42,200—203) and for remote atmospheric monitoring (204). Raman selection rules differ from those of single-photon absorption, depending on change in polarizabiHty rather than change in dipole moment. There is at least one Raman-active vibrational fundamental for every molecule. Relative intensities can vary gready between absorption and scattering. Vibrations of highly polar groups are often strong in the ir and weak in the Raman. The reverse is tme of C—H and C=C stretches and aromatic ring breathing modes.  [c.318]

Carbon-carbon double bonds are usually reduced using hydrogen and a heterogeneous catalyst. The activity of hydrogenation catalysts decreases in the order Pd > Rh > Pt > Ni > Ru. Catalysts other than Pd are especially chosen to minimize migration of hydrogen, e.g. if one wants to deuterate a C C double bond (Ni, Ru), or if hydrogenolysis of sensitive groups is to be prevented (Rh). The ease of hydrogenation is inversely proportional to the number and size of substituents at the C—C multiple bond (W.F. Newhall, 1958). Hydrogenation of tetrasubstituted double bonds is strongly retarded and occurs only, if the double bond shifts to a less hindered position in the presence of catalysts. It may also happen, however, that a di- or trisubstituted double bond isomerizes to a tetrasubstituted double bond, which resists to reduction. Such isomerizations are particularly fast in the presence of protic acids (D.H.R. Barton, 1956).  [c.101]

The entrance of a third or fourth substituent can be predicted by Beilstein s rule. If a substituent Z- enters into a compound C H XY, both X and Y exert an influence, but the group with the predominant influence directs Z- to the position it will occupy. Since all meta-directing groups are deactivating, it follows that ortho—para activating groups predominate when one of them is present on the benzene ring.  [c.39]

Clearly, the presence or absence of an activation energy for chemisorption will depend on the relative position and shapes of the two potential energy curves, and relatively minor displacements could result in there being no activation energy at all. Also, Fig. XVIII-12 simplifies the situation in that the O—O interatomic distance is not indicated, although it also affects the energy that is, the barrier to chemisorption may involve an energy of stretching the O—O bond to match the distance between sites. Thus for the case or the adsorption of hydrogen on various carbon surfaces, the picture can be taken to be that of a hydrogen molecule approaching a pair of surface carbon atoms, with simultaneous H—H bond stretching and C—H bond formation as the final state of  [c.703]

By looking more closely at how molecules move, we find that bonds between two atoms can vibrate, angles between three atoms can bend, and torsions between four atoms can twist. These types of elementary motions can be combined for groups of atoms, leading to the motion of substituents (e.g., the rotation of a methyl group) or even whole domains (e.g., in proteins). If we want to simulate how these motions occur, our protocol must allow the sampling of the fastest possible movement of an atom within the system under consideration. These are the vibrations of bonds involving a hydrogen atom (e.g., a C-H bond in a methyl group), taking between 10 and 100 fs. Therefore, the integration steps when the equations of motion are being solved numerically must be at least one order of magnitude smaller than the fastest motion, i.e., about 1 fs. Otherwise, one would run into problems concerning the numerical stability of the algorithms used. Considering the fact that the rotation around a single bond needs about 100 ps (of course, the number depends strongly on the rotational barrier modulated not only by the atoms involved, but also on the environment), the simulation of this elementary process needs about 10 integration steps. The time necessary for one step depends mainly on the size of the molecule, because the energy of the whole system has to be recalculated for the actual geometry. If one is interested in complex systems like proteins, the calculation of the energy for a specific geometry (a single point) may increase up to 1 s. Additionally, complex motions in proteins occur on a much larger time scale. The folding of some proteins from the denatured state to the active conformation may last about 1 s (or 10 integration steps). Taking these facts into account it is easy to understand that the simulation of such an event is not possible with the computer power and algorithms currently available.  [c.360]

The assumption was made that substituent effects can be analysed in terms of separate contributions from field and inductive effects, defined by the authors thus By the field effect term Fx), we mean the change in the free energy of activation produced by the electrostatic interaction between the pole or dipole of the substituent and the charge on the aromatic ring or on the electrophile in the transition state. By the inductive effect term (Ix), we mean the change in the free energy of activation deriving from a modification of the electronegativity of the I-carbon atom as a result of the difference in the polarity of the C-X and C-H bonds. The transmission factor a was then assumed to be the sum of contributions from the two effects  [c.227]

C—H bonds are polarized by attached unsaturated carbon substituents. Such groups "activate" the neighbouring CHj, CHp or CH groups in the following order CR=NR > COR > CN > COOR > CR = NR > Ph > CR=CRj. Two activating substituents reinforce each other.  [c.9]

Rhodium Ca.ta.lysts. Rhodium carbonyl catalysts for olefin hydroformylation are more active than cobalt carbonyls and can be appHed at lower temperatures and pressures (14). Rhodium hydrocarbonyl [75506-18-2] HRh(CO)4, results in lower -butyraldehyde [123-72-8] to isobutyraldehyde [78-84-2] ratios from propylene [115-07-17, C H, than does cobalt hydrocarbonyl, ie, 50/50 vs 80/20. Ligand-modified rhodium catalysts, HRh(CO)2L2 or HRh(CO)L2, afford /iso-ratios as high as 92/8 the ligand is generally a tertiary phosphine. The rhodium catalyst process was developed joindy by Union Carbide Chemicals, Johnson-Matthey, and Davy Powergas and has been Hcensed to several companies. It is particulady suited to propylene conversion to -butyraldehyde for 2-ethylhexanol production in that by-product isobutyraldehyde is minimized.  [c.458]

Tartaric Acid. A by-product of the wine processing industry, tartaric acid [87-69-4] C H O, is a specialty acidulant used for neutralizing or adjusting pH. It is found in nature in grapes and is often used to augment natural and synthetic grape and other fmit flavors. It is used as a stabilizer in dry ground spices and exhibits synergistic activity with antioxidants as a chelating agent in fats and oils. In the form of potassium acid tartrate, or cream of tartar, it is used in baking powder leavening systems (13).  [c.436]

ButyUithium decomposes thermally to 1-butene and Hthium hydride at elevated temperatures. Dilute solutions of / -butyUithium in hydrocarbon solvents possess a negligible rate of decomposition at ordinary handling temperatures and under an inert atmosphere, eg, argon or nitrogen. For example, the decomposition rate is <0.01% active material per day at 25°C for a 15 wt % solution in hexane (96). However, at elevated temperatures and high concentrations of / -butyUithium, the losses can be significant. For example, the same 15 wt % solution loses about 0.05% to its active material per day at 45°C, and an 85 wt % solution loses about 0.2 wt %/d at the same temperature. The pyrolysis of alkyllithiums was studied both in neat form (97) and in decane solution (98). A 15 wt % solution of / -butyUithium in hexane is 50% decomposed after 5 h at 130°C and after 50 min at 150°C (98). The decomposition rate constants double as the percentage of carbon-bound Hthium decreases from 96 to 76% by the addition of Hthium -butoxide, the oxidation product of / -butyUithium.  [c.227]

All lation. Maleic anhydride reacts with alkene and aromatic substrates having a C—H bond activated by a,P-unsaturation or an adjacent aromatic resonance (31,32) to produce the following succinic anhydride derivatives.  [c.449]

A significant advance in P-agonist therapy occurred with the discovery of metaproterenol [586-06-17, C H yNO, (3 R = CH(CH2)2)- Replacing the catechol subgroup with a resorcinol unit results in a compound which is no longer susceptible to metaboHsm by COMT and therefore has a longer (4 h) duration of action. Metaproterenol has a selectivity profile that is similar to that of isoproterenol, but it is 10—40 times less potent in vitro (46). However, metaproterenol is active if given orally and, therapeutically, it is adniinistered either orally or by aerosol. Better selectivity of action is achieved by the aerosol route, although large or frequentiy repeated aerosol doses may also cause side effects.  [c.439]

An activated slurry process can be used to place impervious sUicon carbide coatings on graphite. A slurry of sUicon carbide, carbon, and appropriate organic binders is appHed to the surface of the graphite by spraying, dipping, or painting. After a low temperature treatment to drive off the binder, the coated substance is heated in the presence of sUicon vapor, which diffuses into the surface to form a SiC layer on the graphite. The coating composition can vary from self-bonded sUicon carbide containing only a few percent of uncombined sUicon to SiC crystals bonded with a continuous sUicon matrix. Successful SiC coatings on complex graphite shapes have been obtained with isotropic graphite substrates possessing compatible thermal expansion coefficients. Resistance to oxidation at 1400°C for 100 h or more has been accompanied by successful service in nuclear reactor environments. Coatings of SiC on graphite faU under compressive loads or impact at levels that do not damage uncoated graphite. This occurs because the graphite is less brittle and deforms underload, whereas the thin, more rigid SiC coating does not.  [c.47]

A typical recipe for batch emulsion polymerization is shown in Table 13. A reaction time of 7—8 h at 30°C is requited for 95—98% conversion. A latex is produced with an average particle diameter of 100—150 nm. Other modifying ingredients may be present, eg, other colloidal protective agents such as gelatin or carboxymethylcellulose, initiator activators such as redox types, chelates, plasticizers, stabilizers, and chain-transfer agents.  [c.439]

Active Dry Yeast (ADY). The production of active dry yeast is very similar to the production of compressed yeast. However, a different strain of yeast is used and the nitrogen content is reduced to 7% of soHds compared with 8—9% for compressed yeast. The press cake made with the active dry yeast strain is extmded through a perforated plate in the form of thin strands with a diameter of 2—3 mm and a length of 3—10 mm. The strands are dried on endless belts of steel mesh in drying chambers (a continuous process) or in roto-louvre dryers (a batch process), with the temperature kept below 40°C. Drying time in drying chambers is 3—4 h and in roto-louvre dryers is 6 h or more. The final moisture level attained is 7.5—8%.  [c.389]

Table 2 shows that commercial organic peroxides are available with 10-h half-life temperature activity varying from about room temperature to about 130°C. Organic peroxide classes such as diacyl peroxides and peroxyesters show a strong correlation between stmctural variation and 10-h half-life temperature activity. Other organic peroxide classes, eg, peroxydicarbonates and monoperoxycarbonates, show very Httie change in activity with stmctural variation. The diperoxyketals and dialkyl peroxides show a moderate change in activity with variation in peroxide stmctures. In the cases of hydroperoxides and ketone peroxides, precise half-hfe data are difficult to obtain owing to the susceptibiUties of these thermally stable peroxide classes to induced decompositions and transition-metal catalysis. Furthermore, radicals are usually generated from these two classes of peroxides at lower temperatures using activators (or promoters), and first-order decomposition rates have no significance. Although the low temperature acyl sulfonyl peroxide, acetyl cyclohexanesulfonyl peroxide (ACSP) [3179-56-4] (with a 10-h half-hfe temperature of 42°C), is stiU used to some extent in bulk vinyl chloride polymerizations (30,31), it is only produced captively hence its peroxide class was not included in Table 2.  [c.223]

At low temperatures metals having b.c.c. and h.c.p. structures become brittle and fail by cleavage, even though they may be tough at or above room temperature. In fact, only those metals with an f.c.c. structure (like copper, lead, aluminium) remain unaffected by temperature in this way. In metals not having an f.c.c. structure, the motion of dislocations is assisted by the thermal agitation of the atoms (we shall talk in more detail about thermally activated processes in Chapter 18). At lower temperatures this thermal agitation is less, and the dislocations cannot move as easily as they can at room temperature in response to a stress - the intrinsic lattice resistance (Chapter 10) increases. The result is that the yield strength rises, and the plastic zone at the crack tip shrinks until it becomes so small that the fracture mechanism changes from ductile tearing to cleavage. This effect is called the ductile-to-brittle transition for steels it can be as high as =0°C, depending on the composition of the steel steel structures like ships, bridges and oil rigs are much more likely to fail in winter than in summer.  [c.143]

Any C—H bond has characteristic vibrations which impart some energy to the molecule in its normal state. This energy is called the zero-point energy. The energy associated with these vibrations is related to the mass of the vibrating atoms. Because of the greater mass of deuterium, the vibrations associated with a C—D bond contribute less to the zero-point energy than those associated with the corresponding C—H bond. For this reason, substitution of protium by deuterium lowers the zero-point enqfgy of a molecule. For a reaction involving cleavage of a bond to hydrogen (or deuterium), a vibrational degree of freedom in the normal molecule is converted to a translational degree of freedom as the bond is broken. The energy difference due to this vibration disappears at the transition state. The transition state has the same energy for the protonated and deuterated species. Because the deuterated molecule has the lower zero-point energy, it has a higher activation energy to reach the transition state, as illustrated in Fig. 4.9.  [c.222]

Although the preparation of this reagent is similar to that for the other alkylmagnesiurn bromides (see Exp. 6), some modifications had to be introduced in view of the volatility of methyl bromide. After the magnesium had been activated by means of BrCH2CH2Br, the mixture was cooled to 5°C, more THF was added, and about one tenth of the solution of CH3Br in THF (0.55 mol in 100 ml of THF) was added from the dropping funnel. After a few minutes the reaction started (note 1) and the temperature was allowed to rise to 30°C. When this reaction had ceased, the mixture was cooled again to 5 or 10°C and the remainder of the solution was added dropwise from the dropping funnel during 1 h. The temperature of the mixture was held between 10 and 15°C. The conversion was terminated by stirring for a further 30 min (without using the cooling bath). For further details see Exp. 6.  [c.16]

Some copper reagents bearing large alkyl groups also show pronounced stereoselectivity, when they react with dihalides. The halogen on the sterically more hindered side of a molecule is substituted much more slowly. An example is the conversion of a gem-dichloride into a chiral dialkyl compound as part of a synthetic sequence for sirenin (K. Kitatani, 1976). Substitution of a vinylic halide was used in the synthesis of juvenile hormones (E.J. Corey, I968B). Michael type alkylations of activated C = C bonds are also possible with copper or-ganyl anions. These reactions are regioselective, because the copper tends to form it-complexes with C=C bonds rather than o-complexes with carbonyl groups (W.C. Still, 1976). They occur also stereoselective at the least hindered side of cyclic systems (G.H. Posner, 1972).  [c.20]

If X = Y = H, the reaction is called dehydrogenation. Synthetically useful are dehydrogenations of tertiary amines by Hg(OAc)2 via immonium ions (see p. 120f. A. Friedrich, 1975) and of carbonyl-, vinyl-, or aryl-activated C—C single bonds by SeOj (see p. 122 N. Rab-john, 1949, 1976), or better by phenylselenium bromide (H.J. Reich, 1975, 1978, 1979), or by quinones (see p. 338 D. Walker, 1967 H.H. Stechl, 1975). Cross-conjugated cyclohexadien-ones from dehydrogenations of cyclohexanones are always easily isomerized into phenols by acids (J.N. Marx, 1974). A more special example is the exhaustive dehydrogenation of partially unsaturated polycyclic skeletons to give aromatic systems in the presence of Pd, Pt, or Se catalysts (W.E. Barth, 1971).  [c.139]

As a class of compounds, nitriles have broad commercial utility that includes their use as solvents, feedstocks, pharmaceuticals, catalysts, and pesticides. The versatile reactivity of organonitnles arises both from the reactivity of the C=N bond, and from the abiHty of the cyano substituent to activate adjacent bonds, especially C—H bonds. Nitriles can be used to prepare amines, amides, amidines, carboxyHc acids and esters, aldehydes, ketones, large-ring cycHc ketones, imines, heterocycles, orthoesters, and other compounds. Some of the more common transformations involve hydrolysis or alcoholysis to produce amides, acids and esters, and hydrogenation to produce amines, which are intermediates for the production of polyurethanes and polyamides. An extensive review on hydrogenation of nitriles has been recendy pubHshed (10).  [c.217]

Acrylonitrile undergoes a wide range of reactions at its two chemically active sites, the nitnle group and the carbon—carbon double bond. Detailed descriptions of specific reactions have been given (19,20). Acrylonitrile polymerizes readily in the absence of a hydroquinone inhibitor, especially when exposed to light. Polymerization is initiated by free radicals, redox catalysts, or bases and can be carried out in the Hquid, soHd, or gas phase. Homopolymers and copolymers are most easily produced using Hquid-phase polymerization (see Acrylonitrile polymers). Acrylonitrile undergoes the reactions typical of nitnles, including hydration with sulfuric acid to form acrylamide sulfate (C3H5N0-H2S04 [15497-99-1y), which can be converted to acrylamide (C H NO [79-06-1]) by neutralization with a base and complete hydrolysis to give acryUc acid (C2H4O2 [79-10-7]). Acrylamide (qv) is also  [c.181]

Since 0.47 MJ of solar energy is trapped as chemical energy in this process, the maximum efficiency for total white-light absorption is 28.1%. Further adjustments are usually made to account for the percentages of photosyntheticaHy active radiation in white light, the light that can actually be absorbed, and respiration. The amount of photosyntheticaHy active radiation in solar radiation that reaches the earth is estimated to be about 43%. The fraction of the incident light absorbed is a function of many factors, such as leaf size, canopy shape, and reflectance of the plant it is estimated to have an upper limit of 80%. This effectively corresponds to the utilization of eight photons out of every 10 in the active incident radiation. The third factor results from biomass respiration. A portion of the stored energy is used by the plant, the amount of which depends on the properties of the biomass species and the environment. For purposes of calculation, assume that about 25% of the trapped solar energy is used by the plant, thereby resulting in an upper limit for retention of the nonrespired energy of 75%. The upper limit for the efficiency of photosynthetic fixation of biomass can now be estimated to be 7.2%, ie, 0.281 X 0.43 X 0.80 x 0.75. For the case where Httle or no energy is lost by respiration, the upper limit is estimated to be 9.7%, ie, 0.281 x 0.43 x 0.80. The low efficiency limit might correspond to land-based biomass, while the higher efficiency limit might be closer to water-based biomass such as uniceUular algae. These figures can be transformed into dry biomass yields by assuming that aH of the fixed carbon dioxide is contained in the biomass as ceUulose, (C H qO ) from the equation  [c.28]

A biogenic origin for the carbonaceous material in petroleum is widely but not universally accepted. An inorganic origin of petroleum has been proposed (1,2) and there is a duaUst theory incorporating both biological and inorganic aspects (3). However, because inorganic processes generate racemic mixtures, the presence of optically active compounds in oils, especially the multiringed cycloalkanes (naphthenes), provides strong support for a biological hypothesis. Oils also contain the so-called chemical fossils or biomarkers, compounds having characteristic molecular stmctures that can be related to living systems. The compounds include isoprenoids, porphyrins, steranes, hopanes, and many others. The relative abundances of members of homologous series are often similar to those in living systems. The strong odd preference in the long-chain normal alkanes (>C is particularly well documented (4). In addition, the lack of thermodynamic equiUbrium among compounds (5), and the close association of petroleum with sedimentary rocks formed in an aqueous environment, suggests a low temperature origin. In this context, low temperature means less than a few hundred degrees Celsius as opposed to temperatures in the 700—1200°C range that characterize igneous processes involving siUcate melts. The elemental composition of petroleum (C,H,N,S,0), the isotopic composition of oils, and the presence of petroleum-like materials in more recent sediments are consistent with a low temperature origin. The evidence supporting a biological source for the material that generates petroleum is extensive (6—8).  [c.161]

Miscellaneous. Dimeric rhodium isocyanide complexes have been suggested for use to convert water to hydrogen and oxygen (159,160). Photochemical activation of some rhodium complexes leads to iatermolecular oxidative addition of aUphatic and aromatic C—H bonds under ambient conditions (161,162). Rhodium complexes have been iavestigated for antibacterial and antitumor properties (163). However, none has been used ia human clincial trials. Rhodium complexes have been used for site-specific DNA recognition and photoactivated strand scission (164). Rhodium platiag has been used to deposit thin, brilliant white, tamish-resistant, wear-resistant coatiags for jewelry (165). Engiaeeriag appHcations uti1i2e rhodium s good sliding contact characteristics or high stable reflectivity (165). Rhodium electroplatiag baths are proprietary, but are based on sulfate or phosphate salts (165).  [c.181]

Activity and Selectivity. The activity of a catalyst refers to its abiUty to promote the desired reaction whereas the selectivity relates to how effective a catalyst is at promoting only a specific reaction. The selectivity which is required in a particular hydrogenation depends on the functional groups present in the material being hydrogenated. Many common functional groups can be reduced by catalytic hydrogenation with varying degrees of difficulty, and often one functional group must be reduced selectively in the presence of other groups which are to be left unchanged. For example, in the reduction of aromatic nitro compounds the catalyst and reaction conditions must be selected so that the nitro group is completely reduced while the aromatic ring is left intact. Since aromatic rings are generally much more difficult to reduce than nitro groups, this reduction can be carried out very selectively. However, other cases exist where it is much harder to selectively reduce one functional group in the presence of another. An impressive example of the selectivity which can be achieved is in the reduction of 2,4-dinitroaniline [97-02-9] (C H N O. Not only is it possible to reduce one of the nitro groups to an amine while leaving the other unchanged, but through proper choice of catalyst and reaction conditions, either 4-nitro-l,2-benzenediamine [99-56-9] (1) (CgH. N202) (27) or 2-nitro-l,4-benzenediamine [5307-14-2] (2) (28) can be made in good yield.  [c.259]

The detectability of minute quantities of radiolabeled tracers makes possible the deterrnination of microquantities of substances. The most effective use of radiotracers has been in biomedical research. For example, a radiolabeled, nonmetabolized tracer for glucose, such as [l- H]-2-deoxyglucose [77590-94 ] is adininistered to a test animal to identify areas of brain activity corresponding to particular external stimuli. An external stimulus is given and the animal is sacrificed. The brain is fro2en, sectioned, and exposed to x-ray film (autoradiography), and the location of the radioactivity is noted. In this way it is possible to relate changes in glucose metaboHsm, which reflects brain activity, to a stimulus, and a stimulus—response map of the brain can be constmcted. This procedure is referred to as neuroanatomical mapping. In a similar way animal tissues can be processed and incubated with tritium or C-labeled dmgs or dmg analogues (Ligands) to localize the site of action or receptors, for dmgs, hormones, and neurotransmitters (21).  [c.440]

Rhenium Carbonyls and Related Compounds. The parent compound of the low valent rhenium compounds is Re2(CO) Q. Dirhenium decacarbonyl [14285-68-8] a white crystalline compound, mp 177°C, is volatile and soluble in most organic solvents. Its preparation in a high pressure reaction between Re20y, H2, and CO was reported in 1941. It has a molecular stmcture of two square pyramidal Re(CO) groups linked by a metal—metal bond. This compound is available commercially as a specialty chemical. It is the precursor to other low valent rhenium carbonyl compounds, including the hahdes, ReX(CO), where X = Cl, Br, or I alkyl, aryl, and acyl compounds, Re(R)(CO) the hydride complexes ReH(CO) [16457-50-0], Re2()J.-H)2(CO)g [38887-05-7], and Re2()J.-H)2(CO) 2 [12146-47-3]-, and hydrocarbon complexes, including Re(CO)2(Tl-C H ) and [Re(NO)(CO)2( Tl-C H )]PFg [12306-73-9], Research in the 1980s and 1990s has focused on the photochemical activation of H2 by Re2(CO)2Q, formation of metal atom clusters, and on the reduction of a coordinated carbon monoxide ligand to methane or methanol. The latter reaction has received much attention because it provides mechanistic information about the Fischer-Tropsch reaction (see Carbonyl Coal CONVERSION PROCESSES).  [c.164]

For most bleaching appHcations a batch treatment with hydrogen peroxide is used, and an activator (or catalyst) is normally requited to increase the rate of bleaching. The most common activator is alkah, and wool bleaching at pH 8—9 for 1 h at 60°C with a stabilized 0.75% peroxide solution is a typical process (109). Under alkaline conditions it is generally accepted that the active bleaching species is the pethydroxy anion OOH , the formation of which is encouraged at higher pH (110). Peroxide bleaching of wool under mild acid conditions (pH 5—6) can also be carried out using a peracid activator such as Prestogen W (BASF) or citric acid (111). As wool sustains some damage in the presence of alkah, this method can be useful when it is necessary to bleach mote dehcate fabrics.  [c.349]


See pages that mention the term C-H or C-C activation : [c.119]    [c.506]    [c.38]    [c.71]    [c.24]    [c.107]    [c.133]    [c.140]    [c.534]    [c.552]    [c.270]    [c.561]    [c.91]    [c.430]    [c.181]    [c.157]    [c.41]    [c.37]    [c.53]    [c.69]   
A life of magic chemistry (2001) -- [ c.167 ]