Bis arsenides

Dieckmann and Hanf, Zeitsch. anorg. Chem., 1914, 86, 291. See also Dieekmann, XJeh r einige Mono- und Bi-Arsenide des Eisens, Mangans und Chroms," Berlin, 1911. 

Treatment of 1,2-phenylenebis(methylarsine) (54) with 2 equiv. of n-butyllithium in THE generates the bis(arsenide) (55) (Scheme 8), which under high-dilution conditions can be used to... 

An interesting feature of the reactions of the bis(arsenide) (55) and the bis(phosphide) (58) is the stereoselective nature of many of their reactions with bis(electrophiles). Thus, except for (56 X = S), where a trace of the R, R ) diastereomer was evident, the reactions in each case afforded the... 

As a final accomplishment, the reaction between (63) and the bis(electrophile) (70) afforded the 24-membered hexa(tertiary arsine) (71) in 15% yield. A 6% yield of (71) resulted from the reverse condensation, that is, the reaction of (66) with the bis(arsenide) (72) (Scheme 11). The product was isolated by column chromatography and characterized by elemental analysis and MS. The ease with which the heterocycles (64) and (69) and (71) can be purified by column chromatography is an important physical property that distinguishes them from similar tertiary phosphines and opens up the possibility for the complete separation of diastereomers. 

The radii in the lowest row of the table were obtained by a number of approximate considerations. For instance, if we assume the bismuth radius to bear the same ratio to the interatomic distance in elementary bismuth as in the case of arsenic and antimony, we obtain (Bi) = 1.16— 1.47 A. A similar conclusion is reached from a study of NiSb and NiBi (with the nickel arsenide structure). Although the structures of the aurous halides have not been determined, it may be pointed out that if they are assumed to be tetrahedral (B3 or Bi) the interatomic distances in the chloride, bromide, and iodide calculated from the observed densities1) are 2.52, 2.66, and 2.75 A, to be compared with 2.19, 2.66, and 2.78 A, respectively, from pur table. 

Bis(trimethylsilyl)arsine reacts with diethyl- or dimethylzinc to form different arsenide complexes with the structure dependent on the steric demands of the alkyl group. In the presence of both methyl and ethyl groups alkylzinc bis(trimethylsilylarsenide) forms which has a trimeric solid state structure (37) with a six-membered Zn3As3 and Zn-As distances with an average of 2.48 A.322... 

The reaction of the lithium bis(trimethylsilyl)arsenide (47) with -butyl phosphaethyne (45) <89TH 423-01,93PS(77)45,94JOM(480)45> or a phosphaalkene precursor thereof (46) leads to a mixture of lithium 1,2,4-triphospholide, 1,2,4-diphosphaarsolide (48) and 1,4,2-diphosphaarsolide (49) (Scheme 11). 

The X-ray crystal structure determination of ferf-butylzinc bis(tert-butyl) arsenide (242) revealed a similar structural feature as observed in 240 and 241, i.e. a flat Zn—As—Zn—As central four-membered ring as a resnlt of -bridging arsenide groups and trigonal planar zinc atoms. ... 

TRIS(TRIMETHYLSILYL)ARSINE AND LITHIUM BIS(TRIMETHYLSILYL)ARSENIDE... 

Tris(trimethylsilyl)arsine and lithium bis(trimethylsilyl)arsenide are valuable reagents for dehalosilylation and salt elimination reactions, respectively. Each compound reacts with a wide variety of metal halides to form metal-arsenic bonds.1, 2 The syntheses reported herein are a modification of the published procedures of Becker et al.,3 designed to minimize the use of Schlenk techniques and to allow researchers to prepare two very useful compounds with a minimum of danger. However, since these compounds do... 

Caution. Lithium bis(trimethylsilyl)arsenide is very sensitive to moisture and can react explosively upon exposure to air. Methyllithium is corrosive and reacts violently with water. Both compounds should be manipulated in a dry argon or nitrogen atmosphere. Lithium bis (trimethylsilyl) arsenide should not be heated above 80°C as it begins to decompose. 

Lithium bis(trimethylsilyl)arsenide is a white powder which is stable at room temperature under an inert atmosphere. It is important for stoichiometric reasons to ascertain whether there is any residual THF. This can be readily determined by H NMR spectroscopy. The H NMR spectrum in C6D6 (reference S 7.15) consists of a single resonance at 0.62. Solubility very soluble in THF and diethyl ether, and minimally soluble in nonethereal solvents. 

The reaction of lithium bis(trimethylsilyl)arsenide 16 with the phosphaalkyne 17 yields an approximately equimolar mixture of lithium 1,2,4- and 1,4,2-diphosphaarsolide 18 and 19 as has been reported in CHEC-II <1994JOM45, 19950M4382, 1996CHEC-II(4)819>. Alkylation of this mixture with bis(trimethylsilyl)bromomethane in DME gives exclusively the 177-1,2,4- and 1 //-l, 4,2-diphosphaarsolcs 20 and 21 (Scheme 3). The two isomers could not... 

One method for the synthesis of cyclic silicon-phosphorus compounds is the reaction of alkaliphosphides with dichlorosilanes [1]. Using sodium/potassium phosphide, -arsenide, -antimonide and -bismutide Na3E/K3E (E = P, As, Sb and Bi) [2] with various di-, tri-, and tetrachloroorganosilanes, cages of the following types (Fig 1.) have been synthesized so far. 

The reactions of chlorooligosilanes with sodium potassium phosphide or arsenide are known to yield cage-like structures composed of SiSi and SiE bonds (E=P, As, Sb, Bi), as shown in Fig. 1 [1]. 

To a suspension of sodium potassium arsenide in DME, a solution of 2,3-bis(chlorodimethylsilyl)-1,4-dichlorohexamethyltetrasilane (6) in DME is added. The reaction mixture is refluxed for 12 h. Afrer filtration of the salts the solvent is removed in vacuo, and 2 is reciystallized from n-heptane. 

Fig. 5. Molecular structures of dimeric zinc bis[bis(trimethylsilyl)arsenide] (left) and trimcric methyl zinc bis(tri-methylsilyl)arsenide (right).

The nickel arsenide structure. The structure most frequently encountered is the NiAs structure (Fig. 17.1), which is also that of many phases MX in which M is a transition metal and X comes from one of the later B subgroups (Sn, As, Sb, Bi, S,... 

The nickel arsenide structure occurs not only in the sulphides but also in many other compounds containing a transition metal and one of the elements Sn, Pb, As, Sb, Bi, Se and Te. Many of these systems are essentially intermetallic in their properties and will be discussed further in the chapter devoted to alloys. Here, however, it is interesting to note that as the system becomes more metallic so the bonding in the vertical direction becomes stronger. Thus in FeS the Fe-S and Fe-Fe distances... 

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