Nitrogen discovery preparation

After Allen s discovery of ruthenium nitrogen complexes,1 many nitrogen complexes of the transition metals have been prepared by various methods. Molybdenum2 and iron3 nitrogen complexes prepared recently are exceptionally interesting because of the key... 

Almost as soon as Pedersen announced his discovery of the crown ethers (see Chaps. 2 and 3) it was recognized by many that these species were similar to those prepared by Busch and coworkers for binding coinage and transition metals (see Sect. 2.1). The latter compounds contained all or a predominance of nitrogen and sulfur (see also Chap. 6) in accordance with their intended use. The crown ethers and the polyazamacrocycles represented two extremes in cation binding ability and preparation of the intermediate compounds quickly ensued. In the conceptual sense, monoazacrowns are the simplest variants of the macrocyclic polyethers and these will be discussed first. 

A number of nitrogen-fixing bacteria contain vanadium and it has been shown that in one of these, Azotobacter, there are three distinct nitrogenase systems based in turn on Mo, V and Fe, each of which has an underlying functional and structural similarity.This discovery has prompted a search for models and the brown compound [Na(thf)]+[V(N2)2(dppe)2] (dppe = Pli2PCH2CH2PPh2) has recently been prepared by reduction of VCI3 by sodium naphthalenide... 

Knorr reported the first pyrazole derivative in 1883. The reaction of phenyl hydrazine and ethylacetoacetate resulted in a novel stmcture identified in 1887 as l-phenyl-3-methy 1-5-pyrazolone 9. His interest in antipyretic compounds led him to test these derivatives for antipyretic activity which led to the discovery of antipyrine 10. He introduced the name pyrazole for these compounds to denote that the nucleus was derived from the pyrrole by replacement of a carbon with a nitrogen. He subsequnently prepared many pyrazole analogs, particularly compounds derived from the readily available phenyl hydrazine. The unsubstituted pyrazole wasn t prepared until 1889 by decarboxylation of liT-pyrazole-3,4,5-tricarboxylic acid. ... 

Application of an organocatalytic domino Michael addition/intramolecular aldol condensation to the preparation of a series of important heterocycles has recently received much attention [158] with methods being disclosed for the preparation of benzopyrans [159-161], thiochromenes [162-164] and dihydroquinolidines [165, 166]. The reports all use similar conditions and the independent discovery of each of these reactions shows the robust nature of the central concept. A generalised catalytic cycle which defines the principles of these reports is outlined in Fig. 10. Formation of iminium ion 102 is followed by an intermolecular Michael addition of an oxygen, sulfur or nitrogen based nucleophile (103) to give an intermediate... 

Professor of physics at Cavendish Laboratory, Cambridge. He made elaborate investigations of the electrochemical equivalent of silver and of the combining volumes and compressibilities of gases. His observation that nitrogen prepared from the atmosphere is heavier than nitrogen prepared from ammonia led to the discovery of argon, the first noble gas. He also contributed to optics and acoustics. 

At Los Alamos National Laboratory, USA, Chavez et al. still continue their work on the development and discovery of new high nitrogen content-HEMs for various applications [281, 285-287] and recently reported the preparation of several novel nitroguanyl-substituted tetrazines including 3,6-bis(nitroguanyl)-l,2,4,5-tetrazine [Structure (2.71)] and bis (triaminoguanidinium) salt [Structure (2.72)] as shown in Figure 2.6. 

A recipe for the preparation of Prussian Blue was published 20 years after its discovery.10 " Since materials containing iron, potash and nitrogenous matter such as blood or animal hooves may have been heated together in more remote times, ferrocyanides [hexacyanoferrates(II)] probably antedate Diesbach s discovery. They contain Fe—CN bonds and may thus possibly be considered as the first known examples of coordination compounds containing transition metal—carbon bonds (organometallic compounds). 

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