Complexation of 4-amino-1,3 dimethyl-2,6 pyrimidine-dione derivatives with cobalt(II) and nickel(II) ions: synthesis, spectral, thermal and antimicrobial studies

Abstract

Four heterocyclic Schiff-base ligands derived from condensation of 4-amino-1,3 dimethyl-2,6 pyrimidine-dione with 2-hydroxybenzaldehyde, 2-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde and 4-(dimethylamino) benzaldehyde, (HL 1 , L 2 , HL 3 and L 4 ), respectively, and their Co(II) and Ni(II) complexes have been prepared and characterized via elemental analysis, molar conductance, magnetic moment, thermal and XRPD analysis as well as spectral data (IR, 1 H-NMR, mass and solid reflectance). IR data reveal that the ligands are bidentate neutral ligands except HL 1 , which is monobasic tridentate with coordination sites azomethine (N), carbonyl (O) and phenolic (O). Conductance data suggest that all complexes are nonelectrolytes, except cobalt(II) complexes of L 2 and HL 3 are 1 : 1 electrolytes. The mass spectra confirm the proposed structure of the ligands and their complexes. The solid reflectance spectral data and magnetic moment measurements suggest octahedral, tetrahedral and square planar geometrical structures for the metal complexes. The spectral data were utilized to compute the important ligand field parameters B, and D q ; LFSE also was calculated. The thermal behavior is also studied. Antibacterial and antifungal properties of the ligands and their complexes show broad-spectrum activities and the metal complexes show higher activity than the free ligands.

Synthesis, Spectroscopic, Anticancer, and Antimicrobial Properties of Some Metal(II) Complexes of (Substituted) Nitrophenol Schiff Base

“…The protons at C 3 , C 4 , and C 6 resonate as a multiplet at 8.41-8.19 ppm and are downshifted. Similarly, those at C 5 , C 6 , and C 7 in indane ring also resonate as a multiplet and are downshifted to 7.00-7.14 ppm. Likewise, the 2H at C 1 are seen as a triplet centered at 3.00 ppm and are downshifted.…”

“…The protons on C 3 , C 4 , and C 6 resonate as a multiplet at 8.42-8.22 ppm. The protons at C 5 , C 6 , and C 7 in indane ring are observed as a multiplet at 7.29-7.06 ppm. The 2H at C 1 are seen as a triplet centered at 3.02 ppm while those at C 2 resonate as a quintet centered at 2.15 ppm.…”

“…The imine proton is seen as a singlet at 8.70 ppm. The protons at C 3 , C 4 , and C 6 , and those at C 5 , C 6 , and C 7 in indane ring resonate as multiplets at 7.70-7.95 and 6.95-7.32 ppm, respectively, and are downshifted. The 2H at C 1 and C 3 are upshifted and seen as a triplet each centered at 3.03 ppm and 3.08 ppm, respectively, while 2H at C 2 are seen as a quintet at 2.06 ppm and are downshifted.…”

“…Additionally, Schiff bases derived from indane-1, 3-dione-2-imine-N-acetic acid, 2imino-N-2-propionic acid and ninhydrin, glycine/L-alanine, and their metal(II) com-plexes exhibit unique geometries, and good antimicrobial activities against E. coli, P. mirabilis, S. aureus, and P. faecalis [4,5], while those derived from 4-amino-1,3-dimethyl-2,6-pyridinedione and various hydroxy benzaldehyde are potent antimicrobials. Tricyclic pyrimidine and aminobenzene sulfonamido Schiff bases showed anti-HIV activity and high antitumor activity with low therapeutic index against murine S-180 carcinoma [6][7][8], and N-substituted-3-chloro-2-azetidinones Schiff bases have good anthelmintic activity against earthworms [9]. Extensive literature search shows that no work is reported on the Schiff base, 2-[(2,3-dihydro-1H-inden-4ylimino)methyl]-5-nitrophenol (derived from condensation of 4-aminoindane and 2-hydroxy-5-nitrobenzaldehyde) and its Mn(II), Cu(II), Zn(II), and Pd(II) complexes [10][11][12][13][14].…”

Synthesis, Characterization, Biological and Antitumor Activity of Co(II) , Ni (II) , Cu(II) and Zn (II) Complexes of N-(2-Chlorophenyl)-N’-Benzoyl Thiourea

“…Absorption bands from 560 to 720 (nm) which can be assigned to metal ligand charge transfer MLCT in a low spin tetrahedral geometry of Zn (II) complex confirmed by the diamagnetic properties. The assignments of the observed electronic transitions apart from that together with the geometry and the magnetic moment values [23,24] are listed in Table 3. ( )…”