Sulfur nitrogen complexes

Several Japanese processes (1, 2), such as the Ishikawajima, Chiyoda, or Mitsubishi processes in which the NO in the flue gas is oxidized to NO2 by O3 and subsequently passed to a NO2/SO2 absorber, have shown that a major fraction of the absorbed N0X is in the form of nitrogen-sulfur complexes, which are the compounds produced in the reaction between nitrite and sulfite ions. 

Nodule-forming bacteria (legume bacteria) live in symbiosis with the root system of legumes (e.g. beans). They can reduce nitrogen to ammonia with the aid of a molybdenum-sulfur complex. 

Most organic compounds are not as simple as these compounds. Carbon compounds can contain still other elements, such as nitrogen, sulfur, and chlorine, and their molecules are often very complex. 

Based on donor atom type, macrocyclic ligands can be considered to span two extreme types. First there are those systems which chiefly contain nitrogen, sulfur, phosphorus, and/or arsenic donors. These macrocycles tend to have considerable affinity for transition and other heavy metal ions they usually show much less tendency to form stable complexes with ions of the alkali and alkaline earth metals. The present discussion will be restricted to a consideration of a selection of such ligands and their complexes. 

Before we get any further, I want to divide the chemical elements into two classes to facilitate an understanding of the structural chemistry of molecules. The first class includes those elements that form more than one chemical bond at a time. Carbon typically makes four chemical bonds and provides an example of such an element. Oxygen, nitrogen, sulfur, and phosphorus provide four additional examples of elements that typically make more than one chemical bond. Elements in this class provide for structural complexity, since, in principle at least, they can make straight chains, branched chains, cyclic structures, and so on. 

With time of flight instruments, a mass accuracy better than 5 ppm can be achieved, while with Fourier transform ion cyclotron resonance or orbitrap mass spectrometers mass accuracies better than 1 ppm have been reported. It is obvious that, for good mass accuracies, the peaks must be baseline resolved and resolution plays an essential role. For the present example, a mass resolving power of 5000 seems to be quite acceptable. In the case of the [M+H]+ + 1 isotope peak, the situation becomes somewhat more complex for molecules containing nitrogen, sulfur or carbon. Figure 1.5 D illustrates at a mass resolving power of 500000 the contribution of... 

Compared with the large number of nitrosyl complexes, only a few examples of thionitrosyl complexes have been studied. Although NS does not exist, a number of synthetic approaches to thionitrosyl complexes have been reported the reaction of nitrido complexes with S2CI2 or TMSNCS, treatment of chloro or 0x0 complexes with trithiazyl chloride or S(NTMS)2, or the use of heterocyclic nitrogen-sulfur rings. Pre-formed thionitrosyl cations in [NS][SbF6] or [NS)[AsFg] have been used to prepare the cationic complex [Re(NS)(CO)5] " in liquid S02. ... 

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