Cyanides structures

Ludi, A. and Gtidel, H.L. 1973. Structural chemistry of polynuclear transition metal cyanides. Structure and Bonding, 14, 1-21. 

The structure of silyl cyanides was a matter of dispute for many years. Emeleus, Maddock and Reid (1941) prepared silyl cyanide by the reaction of SiH3I with solid AgCN. The normal cyanide structure was written for this product without comment. However, on the basis of analogy with carbon chemistry, MacDiarmid (1956) suggested that the compound should be formulated as an isocyanide, H3SiNC. The problem Was finally resolved by careful infrared and microwave spectral studies which showed that the normal cyanide, H3SiCN, is correct (Linton and Nixon, 1958 a Mutter and Bracken, 1960 Sheridan and Turner, 1960). 

Two recent structure determinations by Schlemper and Britton (Inorg. Chcm. 5, 408, 511 (1966)), show that trimethyltin cyanide is composed of planar (CHj)jSn groups which are strong into linear chains by CN bridges. They also show that the corresponding germanium compound (see section IIA) is molecular with the primary and possible only from possessing the normal cyanide structure. 

Evidence for the Normal Cyanide Structure of (CH3)3SiCN. J. Chem. Phys. 

When Cd(CN)2 is crystallized in the presence of other molecules that can stuff cavities or tunnels, many different structures are formed depending on the size and shape of the guests that stuff the cavities. Similar behavior is, of course, found elsewhere, e.g., in gas hydrates and hydrothermal synthesis of zeolites. These cadmium cyanide structures may be considered as a new class of clathrates. 

S3mthesis from Cyanogen.—Two methods of synthesis of hydrocyanic acid support the view that this compound has the cyanide structure and not the iso-cyanide. Cyanogen gas because it yields oxalic acid on hydrolysis must have the constitution in which the two cyanogen groups are linked by the carbon atoms rather than nitrogen. 

A number of substituted cyclopropyl cyanide structures have been determined by X-ray and these are also consistent with strong 7r-donation by cyclopropyP. ... 

Metal cyanide, which has received little attention for years in many texts concerned with inorganic structures, is now found to possess the most outstanding feature as a building block for infinite polymeric frameworks. Some rather elegant metal cyanide structures with extended frameworks have recently been discovered (121-128). The synthetic strategy is based on the combination of a diatomic bifunctional rodlike CN ion with a considerable preference for binding metals at each end in a linear fashion together with modification of... 

Legon A 0, Millen D J and Mjdberg P J 1977 The hydrogen cyanide dimer identification and structure from microwave spectroscopy Chem. Phys. Lett. 47 589... 

Dulmage W J and Lipscomb W N 1951 The crystal structures of hydrogen cyanide, HON Acta Crystallogr. 4 330... 

Lewis s concept of shared electron parr bonds allows for four electron double bonds and SIX electron triple bonds Carbon dioxide (CO2) has two carbon-oxygen double bonds and the octet rule is satisfied for both carbon and oxygen Similarly the most stable Lewis structure for hydrogen cyanide (HCN) has a carbon-nitrogen triple bond... 

Mescaline a hallucinogenic amine obtained from the peyote cactus has been synthesized in two steps from 3 4 5 trimethoxybenzyl bromide The first step is nucleophilic substitution by sodium cyanide The second step is a lithium aluminum hydnde reduction What is the structure of mescaline" ... 

In 1959 a new non-protein L-a-amino acid was isolated from the seeds of Acacia willardiana and later from other species of Acacia-, it proved to be l-/3-amino-/3-carboxyethyluracil (977) (59ZPC(316)164). The structure was confirmed by at least four syntheses in the next few years. The most important involves a Shaw synthesis (Section 2.13.3.1.2e) of the acetal (975) and hydrolysis to the aldyhyde (976) followed by a Strecker reaction (potassium cyanide, ammonia and ammonium chloride) to give DL-willardiine (977) after resolution, the L-isomer was identical with natural material (62JCS583). Although not unambiguous, a Principal Synthesis from the ureido acid (978) and ethyl formylacetate is the most direct route (64ZOB407). 

The use of fire retardants in polymers has become more complicated with the realisation that more deaths are probably caused by smoke and toxic combustion products than by fire itself. The suppression of a fire by the use of fire retardants may well result in smouldering and the production of smoke, rather than complete combustion with little smoke evolution. Furthermore, whilst complete combustion of organic materials leads to the formation of simple molecules such as CO2, H2O, N2, SO2 and hydrogen halides, incomplete combustion leads to the production of more complex and noxious materials as well as the simple structured but highly poisonous hydrogen cyanide and carbon monoxide. 

The same structural factors come into play in determining the position of equilibria in reversible additions to carbonyl compoimds. The best studied of such equilibrium processes is probably addition of cyanide to give cyanohydrins. 

Iodide ions reduce Cu to Cu , and attempts to prepare copper(ll) iodide therefore result in the formation of Cul. (In a quite analogous way attempts to prepare copper(ll) cyanide yield CuCN instead.) In fact it is the electronegative fluorine which fails to form a salt with copper(l), the other 3 halides being white insoluble compounds precipitated from aqueous solutions by the reduction of the Cu halide. By contrast, silver(l) provides (for the only time in this triad) 4 well-characterized halides. All except Agl have the rock-salt structure (p. 242). Increasing covalency from chloride to iodide is reflected in the deepening colour white yellow, as the... 

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