Pyridine-2-aldehyde 2’-pyridylhydrazone

Metal chelates of pyridine-2-aldehyde-2 -pyridylhydrazone (paphy) and related ligands. C. F. Bell, Rev. Inorg. Chem., 1979,1,133—161 (46). 

Pyridine-2-aldehyde-2-pyridylhydrazone is a tridentate ligand that forms cationic complexes with dipositive transition metal ions. The protons attached to the nitrogen atoms are readily lost from the chelate rings and an uncharged metal chelate, soluble in organic solvents, is formed, accompanied by a marked color change (87, 88, 132). 

C1iHioCl2CoNh, Dichloro(pyridine-2-aldehyde 2-pyridylhydrazone)co-balt(ll), 31B, 425... 

The cis- (19) and trani -isomers (20) of the Schiff base from pyridine 2-aldehyde and 2-pyridylhydrazone have been... 

A sensitive spectrophotometric method is based on the extraction of the Ni complex with pyridine-2-aldehyde-2-quinolylhydrazone (e = 6.7-10 at 515 nm) [48-50]. The following similar reagents have also been recommended 5-methylfurfural-l-phthalazine-hydrazone [51], 2-pyridinecarbaldehyde-2-(5-nitro)pyridylhydrazone (e = 1.0-10 ) [52], 2-pyridinecarbaldehyde-3,5-dinitro-2-pyridylhydrazone [53], and 1,5-bis(di-2-pyridyl-methylene)thiocarbonylhydrazide [54]. 

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