Lithium, ultrasonic

The piezoelectric constant studies are perhaps the most unique of the shock studies in the elastic range. The various investigations on quartz and lithium niobate represent perhaps the most detailed investigation ever conducted on shock-compressed matter. The direct measurement of the piezoelectric polarization at large strain has resulted in perhaps the most precise determinations of the linear constants for quartz and lithium niobate by any technique. The direct nature of the shock measurements is in sharp contrast to the ultrasonic studies in which the piezoelectric constants are determined indirectly as changes in wavespeed for various electrical boundary conditions. 

SnO has received much attention as a potential anode material for the lithium-ion-secondary-battery. The conventional techniques require temperatures above 150°C to form phase pure SnO. Whereas, sonication assisted precipitation technique has been used to prepare phase-pure SnO nanoparticles at room temperature by Majumdar et al. [25]. In this study, ultrasonic power has been found to play a key role in the formation of phase pure SnO as with a reduction in the ultrasonic power authors have observed a mixed phase. For the case of high ultrasonic power, authors have proposed that, intense cavitation and hence intense collapse pressure must have prevented the conversion of SnO to Sn02-... 

Kim KH, Kim KB (2008) Ultrasound assisted synthesis of nanosized lithium cobalt oxide. Ultrason Sonochem 15 1019-1025... 

Studies of the effects of low frequency ultrasonic waves on a broad range of synthetically useful reactions are summarized. Discussion is centered on the results obtained in our laboratory where we have concentrated on the reactions of metals with functionalized organic and organometallic compounds. Special emphasis is on lithium and zinc with organic and organosilicon halides. 

Reactions involving lithium appear to be particularly good candidates for ultrasonic acceleration. The reduction of some highly unsaturated cyclic hydrocarbons by lithium was not only accelerated but pushed to completion by ultrasonic irradiation(19) ... 

Halides of the less electropositive metals are quickly reduced to highly dispersed and very active metal powders if they are exposed to ultrasonic waves in the presence of lithium and other group I metals(20). Ultrasound not only accelerates the reduction of the halides but also increases the rate of subsequent reactions of these less active metals. These reactions are covered in the chapter by K. Suslick. 

When zinc and a,a -dibromo-o-xylene are irradiated with ultrasonic waves at room temperature, synthetically useful quantities of the reactive intermediate, o xylylene, are generated which can be treated in situ with activated olefins to give good yields of cycloaddition products(30). Chew and Ferrier used this methodolgy to generate a-xylylene for the synthesis of optically pure functionalized hexahydroanthracenes(31). The reaction with lithium takes a different course(19). Rather than generate the -xylylene intermediate, ionic species are produced. The two fates of a, a -dibromo-o-xylene are presented in the scheme below ... 

We examined a variety of dihalosilanes using ultrasonic waves and alkali metals(37). The mild conditions permitted led to fewer products than are normally observed in these reactions and the first evidence that silylenes can be important intermediates in metal-dihalosilane reactions in solution. Our results for some dichlorosilanes reacting with lithium metal are summarized below. 

The ultrasonic preparation of thioamides from amides and phosphorus pentasulfide by Raucher(51) and of dichlorocarbene from chloroform and potassium hydroxide by Regen(52) are some of the more recent examples of nonmetallie applications. We were surprised to find that ultrasound greatly accelerates the reduction of haloaroma-tics by lithium aluminum hydride, permitting the reaction to be... 

The lithium and naphthalene are loaded into the reaction flask in a dry box, and the TMEDA and toluene syringed in under argon. The reaction flask is immersed in an ultrasonic cleaner. Sonication is continued until all of the lithium has dissolved. Upon standing, [(TMEDA)Li] [Nap] crystallizes as black needles. This complex is indefinitely stable under argon at room temperature but decomposes at <80 ° C in solution. 

Trimethyltinlithium, (CH3)3SnLi (1). This reagent can be obtained by reaction of (CH3)3SnCl in THF with lithium at 0° in an ultrasonic vessel. 

A very reactive form of a finely divided metal is a so-called Rieke powder [79]. These materials are produced as fine powders by chemical precipitation during the reduction of various metal halides ivith potassium metal in refluxing tetrahydrofuran. Obviously this is a potentially hazardous laboratory procedure and ultrasound has provided an alternative method of preparation of these extremely valuable reagents [80]. The sonochemical technique involves the reduction of metal halides with lithium in TH F at room temperature in a cleaning bath and gives rise to metal powders that have reactivities comparable to those of Rieke powders. Thus powders of Zn, Mg, Cr, Cu, Ni, Pd, Co and Pb were obtained in less than 40 min by this ultrasonic method compared with reaction times of 8 h using the experimentally more difScult Rieke method (Tab. 3.1). 

In many syntheses activation is not effected by sonochemical preparation of the metal alone but rather by sonication of a mixture of the metal and an organic reagent(s). The first example was published many years ago by Renaud, who reported the beneficial role of sonication in the preparation of organo-lithium, magnesium, and mercury compounds [86]. For many years, these important findings were not followed up but nowadays this approach is very common in sonochemistry. In another early example an ultrasonic probe (25 kHz) was used to accelerate the preparation of radical anions [87]. Unusually for this synthesis of benzoquinoline sodium species (5) the metal was used in the form of a cube attached to the horn and preparation times in diethyl ether were reduced from 48 h (reflux using sodium wire) to 45 min using ultrasound. 

The Bouveault reaction is the preparation of an aldehyde by a one pot reaction between an organic halide and lithium metal in dimethylformamide. Ultrasound has been found to markedly enhance this reaction when it is performed in tetrahydrofuran [93]. Use of an ultrasonic bath at 10-20 °C affords short reaction times of between 5 and 15 min and generates yields in the range 70-88%. Using this methodology the conversion of 1-bromobutane to pentanal (88%) can be achieved in only 5 minutes. This must be contrasted with the yield of less than 10 % which is obtained under the normal stirred conditions in the same time period. This result confirms that the effect of irradiation goes beyond mere agitation (Eq. 3.11). 

Aromatic ketones 569, benzylic alcohols 570 and 571 as well as alkyl aryl ethers 572 reacted with lithium under ultrasonic irradiation in the presence of catalytic amounts of DTBB (2%) in THF to give, after alkylation with an alkyl iodide at 0°C and final... 

In the solid-state structure of dilithiated fluoranthene (235), generated from 234 in dimethoxyethane at room temperature by Bock and coworkers (Scheme 82), lithium-DME units are capping the naphthalene moiety from both sides of the plane alternatingly (compound 235 forms a coordination polymer in the solid state). The metallic lithium, used for the reaction, was activated by ultrasonic irradiation. Moreover, several structures of related polysodium compounds were also characterized in the solid state . 

The reduction of l,l-bis(diphenylphosphanyl) ethylene (248) with an excess of metallic lithium, activated by ultrasonic irradiation, leads to C—C coupling under the formation of a l,l,4,4-tetrakis(diphenylphosphanyl)butane (249) (Scheme 88)". Surprisingly, the lithium centres in the resulting dilithium compound do not form any lithium-carbon contacts, being coordinated by two diphenylphosphanyl groups and two TFIF molecules each. With this strucmral motif, the molecular structure is similar to the one of tris(phosphaneoxide) 20 (Section n. A), also obtained by Izod and coworkers upon deprotonation. ... 

The reaction of hexaphenylbenzene (250) with an excess of metallic lithium, activated by ultrasonic irradiation, was effected by Bock and coworkers ". The reaction is carried out at room temperature and is accompanied by the release of hydrogen gas, caused by the formation of two additional C—C bonds (Scheme 89). The resulting dihthium... 

The boron substructure was eliminated from the imidazo[4,5-i/][l,3,2]diazaborolidine framework 56 following ultrasonic reduction with metallic lithium in THE and anions of the imidazoles 90 formed. The observed reactivity mled out the possibility of isolating the intermediates from these single-electron-transfer reactions <2004CC1860>. 

Diadamantylsilylene Ad2Si formed from Ad2Sil2 upon treatment with lithium under ultrasonic irradiation was compared with that formed upon pyrolysis of a silirane (Scheme 14.39). ... 

Perrild H, Hegedus L, Baastrup PC, et al. Thyroid function and ultrasonically determined thyroid size in patients receiving long-term lithium treatment. Am J Psychiatry 1990 147 1518-1521. Rosenquist M, Bergfeldt H, Aili H, et al. Sinus node dysfunction during long-term lithium treatment. Br Heart J 1993 70 371-375. 

The sensitivities of elements measured by ICP-MS on standard solutions nebulized with an ultrasonic nebuhzer (USN) are roughly 5000 times higher than in LA-ICP-MS when analyzing a fused lithium borate target of geological standard (NIM-G) by quadrupole ICP-MS Elan... 

The triheterometaUic compound [ (PhHN)2(Bu O)LiNaK(tmeda)2 2], containing a 12-vertex Li2Na2K2N/ O2 cage structure (Figure 2.7), was synthesized in 78 % yield from lithium anilide, NaOBu, KOBu and tmeda in hexane under ultrasonication. " ... 

Another 1,2-dilithiodisilane (16) was obtained by Ando and coworkers from 1,2-dichlorodisilane 15 by reaction with excess lithium metal in THF under ultrasonic... 

The first metalated silole, 48, which was characterized unambiguously by means of NMR spectroscopy, has been obtained by Boudjouk and coworkers via reductive cleavage of the Si—Si bond of disilane 47 with lithium or sodium under ultrasonic activation (equation 54)110a. 

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