Determination of Serum Iron and Iron Binding Capacity Using 4-(2-Pyridylazo) Resorcinol (Par)

Extraction-Spectrophotometric Studies on the Complex Formation of Iron(III) with 4-(2-Thiazolylazo)Resorcinol and Tetrazolium Salts

“…[5] J u l y 3 1 , 2 0 1 4 iv) "The IR data support that the ligand is coordinated to the metal ions [Fe II , Cu II , Zn II and Cd II ] in a terdentate manner and complexation with 4-(2-thiazolylazo)resorcinol through the resorcinol OH, azo N and thiazole N." [25] v) "Co-ordination of two molecules of a terdentate ligand would lead to an octahedral complex, lacking a free position for attaching hydroxyl groups." [6] It should be added, that our previous investigations on cobalt-containing extraction systems, namely Co(II)-TAR-TTCwater-chloroform [45], Co(II)-PAR-TTC-water-chloroform [48], Co(II)-PAR-INT-water-chloroform [48], and Co(II)-PARnitron-water-chloroform [49] indicated fast and trouble-free oxidation of Co(II) (d 7 ) to Co(III) (d 6 ). Hence, the suggested Fe(III)Fe(II) reduction, which ensures the same diamagnetic d 6 electron configuration, can hardly even be regarded as a surprise.…”

“…Iron(II) and iron(III) form colored complexes with heterocyclic azo derivatives of resorcinol, such as 4-(2pyridylazo)resorcinol (PAR) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], 4-(2-thiazolylazo)resorcinol (TAR) [8,14,16,[21][22][23][24][25][26], 4-(5-nitro-2-pyridylazo)resorcinol [27], and 4-(4-methyl-2-thiazolylazo)resorcinol [28]. The complexes have high molar absorptivity and can be used for sensitive spectrophotometric determination of iron in various samples [2,7,11,14,21,28]. The anionic iron-PAR species, [Fe III (PAR)2] and [Fe II (PAR)2] 2-, which exist in aqueous solutions at defined pH and PAR concentration, are the most intensively colored.…”