Pyrazyl-pyridyl

The TV-substituted ethylenediamines and propylenediamines can be prepared, according to Goodwin and Lions,1 by the reaction of the diamine with the appropriate aldehyde followed by the reduction of enamine by zinc dust, MBH4 (M = Na, K), or hydrogen with Pt/C catalyst. This method has been employed to obtain pyridyl- and pyrazyl-substituted ligands such as (4)2 or (5),3... 

Amino-phenyl)- -methylester 231 2-Amino-3-phenyl- -nitril 131 2-(4-Amino-phenyl)-3-pyridyl-(3)- -nitril 519 2-Amino-3-pyrazyl-(2)- 546... 

The crystal structures of the lithium salts 8 with bulky aryl substituents exhibit monomeric structures and / -coordination of the dithiocarboxylate to the lithium atom (Fig. 2) [40]. Lithium complexes 9 and 10,bearing pyrazyl and pyridyl groups, respectively, also have monomeric structures, the former of which has / -coordination similar to that of 8. On the other hand, the lithium cation in 10 is chelated by one sulfur atom of the dithiocarboxylate and a nitrogen atom of the pyridyl group [4]. 

The abbreviations for ligands in the transition metal systems described in this chapter are as follows bpy = 2,2 -bipyridine, Bu2bpy = 4,4 -di-tert-butyl-2,2 -bipyridine py = pyridine, H2bip = 2,2 -bi-l, 4,5,6-tetrahydro-pyrimidine, H2bim=2,2 -bi-2-imidazoline, phen=phenanthroline, acac = 2,4-pentanedionato, pyimH = 2-(2 -pyridyl)imidazole, Tp = hydrotris(pyrazyl)-borate. 

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