Group compounds with nitrogen

A little freshly prepared ferrous sulfate is added to the filtrate and the latter hoiled for 1 min. It is acidified with dilute hydrochloric acid, and 1-2 drops of ferric chloride solution added. A deep hlue coloration or precipitate (Prussian hlue) indicates nitrogen (if very little nitrogen is present, a green-blue color is formed initially). This test sometimes fails with substances containing nitro-groups and with nitrogen-containing heterocyclic compounds. 

Atoms Other than carbon can be asymmetric centers. Any atom that has four different groups or atoms attached to it is an asymmetric center. For example, the following pairs of compounds, with nitrogen and phosphorus asymmetric centers, are enantiomers. 

Ruthenium and Osmium Compounds with Group 15 Ligands 6.11.6.1 Compounds with Nitrogen Ligands... 

These apparent anomalies are readily explained. Elements in Group V. for example, have five electrons in their outer quantum level, but with the one exception of nitrogen, they all have unfilled (I orbitals. Thus, with the exception of nitrogen. Group V elements are able to use all their five outer electrons to form five covalent bonds. Similarly elements in Group VI, with the exception of oxygen, are able to form six covalent bonds for example in SF. The outer quantum level, however, is still incomplete, a situation found for all covalent compounds formed by elements after Period 2. and all have the ability to accept electron pairs from other molecules although the stability of the compounds formed may be low. This... 

Nitrogen does form a number of binary compounds with the halogens but none of these can be prepared by the direct combination of the elements and they are dealt with below (p. 249). The other Group V elements all form halides by direct combination. 

In Group 15 (V), nitrogen compounds readily form molecular compounds with BF. Phosphoms compounds also form adducts with BF. Inorganic or organic compounds containing oxygen form many adducts with boron trifluoride, whereas sulfur and selenium have been reported to form only a few (41—43). 

Hydroxypyrroles. Pyrroles with nitrogen-substituted side chains containing hydroxyl groups are best prepared by the Paal-Knorr cyclization. Pyrroles with hydroxyl groups on carbon side chains can be made by reduction of the appropriate carbonyl compound with hydrides, by Grignard synthesis, or by iasertion of ethylene oxide or formaldehyde. For example, pyrrole plus formaldehyde gives 2-hydroxymethylpyrrole [27472-36-2] (24). The hydroxymethylpyrroles do not act as normal primary alcohols because of resonance stabilization of carbonium ions formed by loss of water. 

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