Alkylammonium metal

All of these compounds, whether alkylammonium, metal and p-block carbamates, are potential carriers or sources of carbamic groups, and can be used in the synthesis of organic carbamates [6] if the transfer of the RR NC02 moiety to a suitable organic substrate is accomplished [6, 7]. Moreover, alkylammonium, metal and p-block carbamates, as well as carbamic acid esters, are also potential... 

With the aim of increasing the dimensionality of the conductivity, Nakamura and co-workers pointed out the special properties of alkylammonium-metal (dmit)2 [28]. By mixing the alkylammonium gold(dmit)2 with eicosanoic acid, then oxidizing caref uUy, either with bromine or electrochemically, they obtained a dc lateral conductivity (for 20-layer samples) in the range of 20-30 Siemens cm-. Such a value is far beyond the values of conductivity for LB films published to date. Moreover, the temperature dependence of the conductivity reveals a metal-like behavior, down to about 200 K. Despite the lack of structural information on these films, and the lack of information for films less than 20 layers thick, the results of Nakamura and coworkers are very encouraging, and stress the importance of increasing the dimensionality of conductivity. 

The conductivities of alkylammonium-metal(dmit)2 LB films after oxidation are summarised in Table 14.3. Among others, the LB films of 3C10-Au (tridecyl-methylammonium-Au(dmit)2) showed an unusually high conductivity. The structure and the physical properties of this LB film will be discussed later in detail. 

Talyor et al. have tried to make alkylammonium-metal(dmit)2 LB films without matrix molecules. They utilised divalent salts to improve the film quality. Conductivities after iodine oxidation are also listed in Table 14.3 together with the metal(mnt)2 (mnt = maleonitriledithiolato) salts [205,208,210,211]. 

Iron hahdes react with haHde salts to afford anionic haHde complexes. Because kon(III) is a hard acid, the complexes that it forms are most stable with F and decrease ki both coordination number and stabiHty with heavier haHdes. No stable F complexes are known. [FeF (H20)] is the predominant kon fluoride species ki aqueous solution. The [FeF ] ion can be prepared ki fused salts. Whereas six-coordinate [FeCy is known, four-coordinate complexes are favored for chloride. Salts of tetrahedral [FeCfy] can be isolated if large cations such as tetraphenfyarsonium or tetra alkylammonium are used. [FeBrJ is known but is thermally unstable and disproportionates to kon(II) and bromine. Complex anions of kon(II) hahdes are less common. [FeCfy] has been obtained from FeCfy by reaction with alkaH metal chlorides ki the melt or with tetraethyl ammonium chloride ki deoxygenated ethanol. 

No attempt should be made to purify perchlorates, except for ammonium, alkali metal and alkaline earth salts which, in water or aqueous alcoholic solutions are insensitive to heat or shock. Note that perchlorates react relatively slowly in aqueous organic solvents, but as the water is removed there is an increased possibility of an explosion. Perchlorates, often used in non-aqueous solvents, are explosive in the presence of even small amounts of organic compounds when heated. Hence stringent care should be taken when purifying perchlorates, and direct flame and infrared lamps should be avoided. Tetra-alkylammonium perchlorates should be dried below 50° under vacuum (and protection). Only very small amounts of such materials should be prepared, and stored, at any one time. 

Foreign cations can increasingly lower the yield in the order Fe, Co " < Ca " < Mn < Pb " [22]. This is possibly due to the formation of oxide layers at the anode [42], Alkali and alkaline earth metal ions, alkylammonium ions and also zinc or nickel cations do not effect the Kolbe reaction [40] and are therefore the counterions of choice in preparative applications. Methanol is the best suited solvent for Kolbe electrolysis [7, 43]. Its oxidation is extensively inhibited by the formation of the carboxylate layer. The following electrolytes with methanol as solvent have been used MeOH-sodium carboxylate [44], MeOH—MeONa [45, 46], MeOH—NaOH [47], MeOH—EtsN-pyridine [48]. The yield of the Kolbe dimer decreases in media that contain more than 4% water. 

The arrangement of zinc and sulfur atoms in the Zn4S core is similar to the observed Zn40. Theoretical calculations demonstrated that the compound is a poor model of extended metal chalcogenide semiconductors (ZnS). Octanuclear zinc compounds have also been structurally characterized with this core. In the presence of an alkylammonium cation, a sulfide containing octanuclear zinc species was formed [BzEt3N]2[Zng(S)(SBz)i6].126 The complexes with benzylthiolate... 

Brighteners are applied to cotton by methods similar to direct dyes. By far the most common are triazinyl derivatives of diaminostilbenedisulphonic acid (DAS) of general formula 11.5, where M is an alkali metal, ammonium or alkylammonium cation. Examples of groups Ilj and R2 are shown in Table 11.1. Most suppliers of FBAs market such compounds, often called DAST brighteners. Products in this class have sometimes been marketed because the supplier needed to offer something different for commercial reasons, or to avoid infringing a competitor s patent, rather than for any real technological necessity. 

The hemispherands, spherands, calixarenes, and related derivatives. A number of hosts for which the pre-organization criterion is half met (the hemispherands) (Cram et al., 1982) or fully met (the spherands) (Cram, Kaneda, Helgeson Lein, 1979) have been synthesized. An example of each of these is given by (251) and (252), respectively. In (251), the three methoxyl groups are conformationally constrained whereas the remaining ether donors are not fixed but can either point in or out of the ring. This system binds well to alkali metal ions such as sodium and potassium as well as to alkylammonium ions. The crystal structure of the 1 1 adduct with the f-butyl ammonium cation indicates that two linear +N-H - 0... 

Certain long-chain alkylammonium salts, notably tricaprylmethyl-ammonium chloride (Aliquat 336-S) and tri-Ao-octylamine hydrochloride (TIOA) are liquids, sometimes referred to as liquid anion exchangers, which can form extractable ion pairs or aggregates with anionic metal complexes in the... 

Most of the work on chiral recognition in the ground state deals with salts having chiral, primary alkylammonium cations. Another approach is the chiral discrimination between two enantiomeric anions present as counterions in metal-cation complexes (Lehn et al., 1978). Discrimination between enantiomeric transition states will be dealt with in the next section together with non-chiral mimicry of enzymic catalysis. 

The p-t-butylcalix[4]arenediquinone-bis(methylether) [56], which had previously been synthesized by Gutsche and co-workers, was used as a model compound in these studies. The receptors [54] and [55] have been shown by nmr titration techniques to form 1 1 solution state complexes with group 1 and 2 metal, ammonium and alkylammonium guest species. 

Compounds [54] and [55] have been shown to complex group 1 and 2 metal cations and also ammonium and alkylammonium cations by nmr and UV/Vis spectroscopies and also by a number of solid-state X-ray crystallographically determined structures. The quinone moieties in these molecules constitute not only the coordination site but also the redox-active centre. The complexation... 

Many examples of the phase-transfer catalysed epoxidation of a,(3-unsaturated carbonyl compounds using sodium hypochlorite have been reported [e.g. 7-10]. The addition of transition metal complexes also aids the reaction [11], but advantages in reaction time or yields are relatively insignificant, whereas the use of hexaethyl-guanidinium chloride, instead of a tetra-alkylammonium salt, enhances the rate of epoxidation while retaining the high yields (>95%) [10]. Intermediate (3-haloalkanols are readily converted into the oxiranes under basic conditions in the presence of benzyltriethylammonium chloride [12]. 

The microporous sulfides are synthesized hydrothermally in the presence of alkylammonium templating agents. The GeS4-based composihons include one or more framework-incorporated metals Mn, Fe, Co, Ni, Cu, Zn, Cd and Ga. Over a dozen novel shuctures were reported which have no analogs in the microporous oxides. Ozin et al. have extended this work to a large number of microporous sulfides and selerhdes [53]. It should be noted that the microporous sulfides and selenides are prone to shucture collapse upon calcinahon to remove the template species. 

Similarly, reactive oxide mixtures are also used to synthesize aluminophosphate molecular sieves, usually starting from phosphoric acid along with the addition of alumina and silica sources analogous to those used in zeolite synthesis with a notable exception alkylammonium salts and amines were ultilized in structure-direchng and space filling to the exclusion of alkali hydroxide solutions and alkali metal salts. 

Usually, addition of an appropriate counterion, commonly an alkah metal, ammonium, or tetraalkylammonium permits the isolation of the polyanion. Lithium and sodium salts are generally more water-soluhle than those of the larger cations. In contrast, salts of alkylammonium and similar cations are insoluble in water but can be recrystaUized from several nonaqueous solvents. 

Scanning tunneling microscopy (STM) has been used to determine the dimensions of metal nanoparticles stabilized by alkylammonium salt in combination with high-resolution TEM (51). The difference between the diameter determined by STM (cl in Fig. 9.1.6) and that determined by TEM (clM in Fig. 9.1.6) allows estimation... 

Apart from alkali metal cations [18]crown-6 derivatives can complex and transport primary alkylammonium cations across chloroform membranes <80JCR(S)136). This process is particularly relevant as many amines (e.g. amphetamine) are physiologically important species. 

BF3 reacts smoothly, in inert solvents, with alkali metal sulfates and phosphates to give stable 2 1 and 3 1 complexes (Table 9), whereas the intermediate complexes that form with NOT, SO and COl- decompose to [BF4] and B203.55 Brownstein et al. have established114 that BF3 reacts easily with alkylammonium salts in CH2C12 or liquid S02. [BF3A]- complex anions are formed with the salts of strong acids (equation 17) whereas complexes with salts of weak acids easily undergo disproportionation (equation 18) and/or conversion into a 2 1... 

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