New series of Ag, Cd(II), Ce(III), Co(II), Cr(III), Fe(III), Ni(II) and Pb(II) complexes with ( E)- N-(4-(2- hydroxybenzylideneamino) phenylsulfonyl) {S.S} have been synthesized. These compounds have been characterized by different physico-chemical techniques like, melting point, elemental analysis, FT-IR, UV spectroscopy, 1H NMR spectroscopy, conductance measurements, magnetic susceptibility and mass spectral analysis. The metal ions concentrations have been determined using inductively coupled plasma mass spectrometry (ICP-MS). Spectroscopic studies suggest coordination most of complexes in a regular octahedral arrangement in 2L:1M molar ratio by two N azomethine and two OH phenolic from Schiff base {S.S} in the form of [ML 2(H 2O) 2], M metal, L ligand {S.S}. Complexes have been screened for their antibacterial {Gram negative bacteria ( Escherichia coli and Pseudomonas aeruginosa)}, {Gram positive bacteria ( Bacillus subtilis and Sterptococcus pneumoniae)} and antifungal ( Aspergillus fumigates and Candida albicans) showing promising antimicrobial biological activity.
Schiff bases are the compounds containing azomethine group (-HC=N-) which were first reported by Hugo Schiff in 1864 and formed by condensation of a primary amine with an active carbonyl compound, and generally take place under acid, base catalysis or with heat [
All chemicals and solvents employed in synthesis were of extra-pure grade and used as received without any further purification. Sulfacetamide were obtained as a donated sample from Epico Pharm (Cairo Egypt). Melting points were taken on (BI Bamtead Electothermal) and are uncorrected. TLC was visualized by VL-6-LC, UV lamp. Elemental analysis (C, H, N, S) was carried out at Fisons EA 1108 CHNS Micro analyzer. Metal ions concentrations were measured using ICP-MS Perkin Elmer/Optima 7000 with a Cetax LSX-200 UV laser module. The UV spectra of compounds were recorded by UV-Vis. Spectrophotometer (UV-1700, Shimadzu). Molar conductance measurements were made in DMF at 25˚C ± 5˚C using a Systronics conductivity bridge model 305. Magnetic susceptibility was measured on powdered samples using the Sherward scientific magnetic susceptibility balance. The diamagnetic corrections were made by Pascal’s constant and Hg[Co(SCN)4] was used as the calibrant. Mass spectral analysis were measured using Shimadazu Qp-2010 plus. Infrared spectra were recorded by a Perkin-Elmer FT-IR 1650 spectrophotometer in wave number region 4000 - 400 cm−1 as KBr pellet. The 1H NMR spectra were recorded using Mercury-300 bb “NMR 300 MHz”, using DMSO-as solvent and tetramethylsilane (TMS) as an internal standard. Antibacterial and antifungal activities measured at The Regional Center for Mycology and Bitechnology, Al-Azhar University, Cairo, Egypt.
The compounds were prepared by adding a hot ethanolic solution of Salicylaldehyde (0.03 mole) to a hot etanolic solution of (0.03 mole) sulfacetamide with vigorous stirring in 1:1 molar ratio, the reaction refluxed for 3 hours until a yellow precipitate formed, which then washed several times and recrystallized from ethanol, and dried in a vacuum over anhydrous calcium chloride The crude product was further purified by preparative TLC (silica gel) as adsorbent(stationary phase) using Di ethyl ether/EtOAc (1:1) (mobile phase) to afford the desired product.
Melting point was (209˚C - 211˚C) yield 70%, molecular weight (318.07) g per mol C15H14N2O4S, Elemental analysis: calc. (found): C 56.59 (55.97), H 4.43 (4.80), N 8.80 (8.31), S 10.07 (10.01).
Silver complex was prepared by adding a hot water solution of AgNO3 (0.03 mole) with vigorous stirring to a hot etanolic solution of (E)-N-(4-(2-hydroxybenzylideneamino) phenylsulfonyl) acetamide {S.S} (0.03 mole) in 1M:1L molar ratio, the remaining complexes were prepared by adding a hot etanolic solution (or distilled water) of metal salt (0.03 mole) to a hot etanolic solution of ligand (0.06 mole) in 1M:2L molar ratio M:L. The reaction refluxed for many hours until a colored (or sometimes white) precipitate formed, which then washed several times and recrystallized from ethanol (or distilled water) then dried in a vacuum over anhydrous calcium chloride.
5 ml of the internal standard is added to a test tube along with 10 - 500 microliters of metal complex sample (internal standard consists primarily of deionized water, with nitric or hydrochloric acid, and Indium and/or Gallium, depending on the sample type). This mixture is then vortexed for several seconds until it is sufficiently mixed and then loaded onto the auto sampler tray. Operation Parameters for determination of elements by ICP- MS are shown in
Most of the complexes were colored, stable at room temperature for extended periods, decompose on heating., they are insoluble in water and many common organic solvents (S.S-Co 2:1 complex was readily soluble in water). They are readily soluble in strong coordinating solvents like DMF and DMSO. The analytical data showed that the most of the complexes had stoichiometry of the type [ML2(H2O)2], where M is metal and L is {S.S} ligand, except Ag complex forming a silver salt of Schiff base reacts in 1L:1M molar ratio (Ag L), as shown in
Parameters | Parameters value |
---|---|
Flush pump rate | 1.85 mL∙min−1 |
Analysis pump rate | 1.85 mL∙min−1 |
Pump relaxation time | 0 s |
RF power | 1350 w |
Nebulizer flow | 26.0 psi |
Auxiliary gas | 1.0 lpm |
Gate 1 | 5 s |
Gate 2 | 15s |
Light source | ICAP |
ICAP view | Axial |
Replicate numbers | 3 |
Detection wavelength/nm | Ag 338.289, Cd 228.802, Ce 413.380 Co 238.892, Cr 205.560, Cu 327.393, Ni 221.648, Pb 220.353 |
Compds. symbol | Reactants | Products | ||||
---|---|---|---|---|---|---|
Ligand | Metal salts | Color | M.P ˚C | Yield (%) | M.F. (M.wt) | |
S.S-Ag 1:1 | S.S | AgNO3 | Black | >300 | 77.2 | C15H13AgN2O4S (425.21) |
S.S-Cd 2:1 | S.S | 3CdSO4∙8H2O | White | >300 | 56.3 | C30H30CdN4O10S2 (783.12) |
S.S-Ce 2:1 | S.S | Ce(NO3)3∙6H2O | Yellow | >300 | 55.2 | C30H28CeN5O12S2 (854.82) |
S.S-Co 2:1 | S.S | CoCl2∙6H2O | Rose | >300 | 81.5 | C30H30CoN4O10S2 (729.64) |
S.S-Cr 2-1 | S.S | CrCl3∙6H2O | Green | 201 - 203 | 83.8 | C30H28ClCrN4O9S2 (740.14) |
S.S-Fe(III) 2-1 | S.S | Fe(NO3)3∙9H2O | Yellow | >300 | 71.8 | [C30H30FeN4O10S2]3+(NO3)33∙3(H2O) (966.62) |
S.S-Ni 2:1 | S.S | NiSO4∙6H2O | White | >300 | 52.6 | C30H30NiN4O10S2 (729.40) |
S.S-Pb 2:1 | S.S | Pb(NO3)2 | White | 221 223 | 85.5 | C30H30PbN4O10S2 (877.91) |
According to pervious data the reaction of forming Schiff base and complexes can be expressed as shown in
In case of Ag complex the proposed structure is as shown in
The results of elemental analyses as shown in
Compd. Symbol | C% | H% | N% | S% | M % (ICP) |
---|---|---|---|---|---|
S.S-Ag 1:1 | 42.37 42.71 | 3.08 3.05 | 6.59 6.48 | 7.54 7.68 | 25.37 25.42 |
S.S-Cd 2:1 | 46.01 46.22 | 3.86 3.46 | 7.15 7.11 | 8.19 8.13 | 14.35 14.23 |
S.S-Ce 2:1 | 42.15 42.41 | 3.30 3.46 | 8.19 8.23 | 7.50 7.72 | 16.39 16.32 |
S.S-Co 2:1 | 49.38 49.32 | 4.14 4.08 | 7.68 7.69 | 8.79 8.82 | 8.08 8.13 |
S.S-Cr 2-1 | 48.68 48.75 | 3. 81 3.78 | 7. 57 7.64 | 8.66 8.72 | 7.03 7.12 |
S.S-Fe(III) 2-1 | 37.28 37.11 | 3.75 3.70 | 10.14 10.12 | 6.63 6.72 | 5.78 5.86 |
S.S-Ni 2:1 | 49.40 49.53 | 4.15 3.97 | 7.68 7.73 | 8.79 8.63 | 8.05 8.12 |
S.S-Pb 2:1 | 41.04 41.47 | 3.44 3.27 | 6.38 6.45 | 7.30 7.36 | 23.60 23.83 |
Preliminary identification regarding the formation of Schiff base compound were obtained from the absence of IR bands characteristic for amino group of aryl amine and the carbonyl group of aldehyde. This is further confirmed by the appearance of a new band characteristic of νC=N [
By using the relation Λm = K/C, the molar conductance of the complexes (Λm) can be calculated, where C is the molar concentration of the metal complex solutions, K = specific conductivity of the complex. The chelates were dissolved in DMF, the molar conductivities of 10−4 M of their solutions at 25˚C ± 2˚C were measured.
Compounds/Bands | υH2O br | υN-H | υC=O | υC=N | υSO2as | υSO2sym | υM-N | υM-O |
---|---|---|---|---|---|---|---|---|
S.S | υO-H br at 3483 | 3379 | 1647 | 1544 | 1319 | 1144 | - | - |
S.S-Ag 1:1 | υO-H br at 3480 | 3283 | 1643 | 1542 | 1313 | 1141 | 549 | - |
S.S-Cd 2:1 | 3448 | 3376 | 1642 | 1599 | 1311 | 1142 | 550 | 454 |
S.S-Ce 2:1 | 3450 | 3388 | 1648 | 1578 | 1319 | 1144 | 554 | 449 |
S.S-Co 2:1 | 3451 | 3381 | 1649 | 1578 | 1320 | 1150 | 554 | 460 |
S.S-Cr 2-1 | 3447 | 3382 | 1644 | 1596 | 1310 | 1150 | 541 | 456 |
S.S-Fe(III) 2-1 | 3450 | 3385 | 1648 | 1591 | 1315 | 1149 | 550 | 467 |
S.S-Ni 2:1 | 3444 | 3384 | 1640 | 1584 | 1321 | 1148 | 555 | 454 |
S.S-Pb 2:1 | 3449 | 3374 | 1641 | 1594 | 1314 | 1148 | 539 | 448 |
Compds. Symbol | λmax nm | Λm∙Ω−1∙mol−1∙cm2 | μeff. (B.M.) | Geometry |
---|---|---|---|---|
S.S | 361, 324, 271, 259, 229, 213. | - | - | - |
S.S-Ag 1:1 | 717, 503, 454, 334, 296 269, 229, 208. | 7.7 | Diamagnetic | Planner |
S.S-Cd 2:1 | 633, 538, 457, 342, 283, 255, 229, 215. | 22.1 | Diamagnetic | Octahedral |
S.S-Ce 2:1 | 601, 522, 454,347, 284, 259, 227, 213. | 8.57 | 2.98 | Octahedral |
S.S-Co 2:1 | 640, 573, 496, 451, 366, 311 281, 259, 225, 213. | 11.8 | 4.58 | Octahedral |
S.S-Cr 2-1 | 742, 633, 538, 459,418, 365, 303. 286, 253, 223, 213. | 6.2 | 3.76 | Octahedral |
S.S-Fe(III) 2-1 | 665, 544, 449, 366, 313, 276, 259, 224, 214. | 195.97 | 5.77 | Octahedral |
S.S-Ni 2:1 | 698, 633, 538, 460, 363, 292.255, 229, 215. | 9.39 | 3.22 | Octahedral |
S.S-Pb 2:1 | 725, 662, 576, 452, 345, 296, 263, 232, 214. | 27.43 | Diamagnetic | Octahedral |
The magnetic moments values, µeff of the Ce(III)complex is 2.98 B.M., being consistent with mononuclear complex and free from antiferromagnetism [
The electronic spectra for all the compounds were obtained in DMSO solutions. The UV-VIS spectra of the ligand {S.S}, showed many bands at 271 nm, and 324 nm, assigned to π → π* (phenyl group nm, C=C), n → π* transitions within the molecule (C=O) respectively [
The mass spectra of complexes are given in
1H NMR for ligand {S.S} is shown in
Compound symbol | Molecular ion (M+) peak at m/z | Relative intensity (%) |
---|---|---|
S.S | C15H14N2O4S (318.07) | 73.5 |
S.S-Ag 1:1 | C15H13AgN2O4S (425.21) | 88.4 |
S.S-Cd 2:1 | C30H30CdN4O10S2 (783.12) | 61.1 |
S.S-Ce 2:1 | C30H28CeN5O12S2 (854.82) | 66.8 |
S.S-Co 2:1 | C30H30CoN4O10S2 (729.64) | 86.1 |
S.S-Cr 2-1 | C30H28ClCrN4O9S2 (740.14) | 77.4 |
S.S-Fe(III) 2-1 | [C30H36FeN7O22S2]3+(NO3)3−3∙3(H2O) (966.62) | 82.0 |
S.S-Ni 2:1 | C30H30NiN4O10S2 (729.40) | 69.9 |
S.S-Pb 2:1 | C30H30PbN4O10S2 (877.91) | 92.8 |
Compound | Chemical shift, (δ) ppm & Assignment |
---|---|
{S.S} | 12.88 (s, 1H, OH) 11.85 (s, 1H, NH) 8.96 (s, 1H, CH=N) 6.96 - 7.83 (d, 8H, ArH) 1.68 (s, 3H, CH3) |
S.S-Ag 1:1 | 12.80 (s, 1H, OH) NH absent 8.92 (s, 1H, CH=N) 6.82 - 7.71 (d, 8H, ArH) 1.61 (s, 3H, CH3) |
S.S-Cd 2-1 | OH absent 11.89 (s, 2H, NH) 8.53 (s, 2H, CH=N) 6.69 - 7.88 (d, 16H, ArH) 1.70 (s, 6H, 2CH3) |
S.S-Pb 2:1 | OH absent 11.82 (s, 2H, NH) 8.40 (s, 2H, CH=N) 6.54 - 7.66 (d, 16H, ArH) 1.62 (s, 6H, CH3) |
gion of 1. 61 - 1.70 ppm were attributed to the methyl group. The N-H proton give a singlet signals in the region 11.82 - 11.89 ppm (s) which nearly not changed compared to ligand, this indicate NH group is not involved in the coordination of Cd and Pb complexes, but the Ag complex we found N-H proton disappeared which confirm participating of this group in the coordination, by losing H proton. Signals for the methine protons of the azomethine group, were observed between 8.96 and 8.40 ppm, the coordination of azomethine nitrogen is confirmed by down field shift in Cd and Pb complexes, also OH appear in ligand at 12.88 ppm but disappear in Cd and Pb complexes ensure coordination of phenolic oxygen to metal ion in Cd and Pb complexes, These numbers of protons results give a good agreement with CHNS calculated and found results.
This test was performed using the diffusion agar technique [
Mean zone of inhibition in mm ± Standard beyond well diameter (6 mm) (100 ml was tested) produced on a range of clinically pathogenic microorganisms using (5 mg per ml) concentration of tested samples. Results are depicted in
Sample Tested Microorganisms | S.S | S.S-Ag 1:1 | S.S-Cd 2:1 | S.S-Ce 2:1 | S.S Co 2:1 | S.S-Cr 2:1 | St. |
---|---|---|---|---|---|---|---|
Fungi | Amphotericin B | ||||||
Aspergillus fumigates (RCMB 02568) | 11.2 ± 0.15 | 17.4 ± 0.82 | 12.8 ± 0.21 | 16.7 ± 0.54 | 24.5 ± 0.24 | 26.3 ± 0. 20 | 23.7 ± 0.1 |
Candida albicans (RCMB 05036) | 11.4 ± 0.23 | 18.4 ± 0.67 | 19.4 ± 0.34 | 17.8 ± 0.02 | 22.3 ± 0.17 | 19.4 ± 0.78 | 25.4 ± 0.1 |
Gram positive bacteria | Ampicillin | ||||||
Sterptococcus pneumonie (RCMB 010010) | 12.2 ± 0.75 | 20.2 ± 0.37 | 15.5 ± 0.84 | 18.7 ± 0.22 | 14.8 ± 0.56 | 22.2 ± 0.41 | 23.8 ± 0.2 |
Bacillus subtilis (RCMB 010067) | 11.3 ± 0.86 | 16.5 ± 0.79 | 21.9 ± 0.28 | 18.2 ± 0.34 | 26.7 ± 0.11 | 25.6 ± 0.11 | 32.4 ± 0.3 |
Gram negative bacteria | Gentamicin | ||||||
Pseudomonas aeruginosa (RCMB 010043) | 10.1 ± 0.29 | 13.2 ± 0.88 | 14.0 ± 0.77 | 10.1 ± 0. 33 | 11.3 ± 0.66 | 16.1 ± 0.72 | 17.3 ± 0.1 |
Escherichia coli (RCMB 01052) | 8.9 ± 0. 12 | 11.8 ± 0.18 | 10.7 ± 0.92 | 13.2 ± 0.67 | 19.3 ± 0. 55 | 18.5 ± 0.99 | 19.9 ± 0.3 |
Sample Tested Microorganisms | S.S-Fe(III) 2-1 | S.S-Ni 2-1 | S-Pb 2-1 | St. |
---|---|---|---|---|
Fungi | Amphotericin B | |||
Aspergillus fumigates (RCMB 02568) | 15.9 ± 0.38 | 13.5 ± 0.64 | 17.8 ± 0.50 | 23.7 ± 0.1 |
Candida albicans (RCMB 05036) | 14.7 ± 0.52 | 19.5 ± 0. 27 | 19.4 ± 0.22 | 25.4 ± 0.1 |
Gram positive bacteria | Ampicillin | |||
Sterptococcus pneumonie (RCMB 010010) | 14.9 ± 0.61 | 16.3 ± 0.79 | 12.4 ± 0.88 | 23.8 ± 0.2 |
Bacillus subtilis (RCMB 010067) | 13.7 ± 0.42 | 19.0 ± 0.38 | 18.1 ± 0.31 | 32.4 ± 0.3 |
Gram negative bacteria | Gentamicin | |||
Pseudomonas aeruginosa (RCMB 010043) | 13.2 ± 0.38 | 10.3 ± 0.78 | 14.8 ± 0.33 | 17.3 ± 0.1 |
Escherichia coli (RCMB 01052) | 12.8 ± 0.38 | 11.9 ± 0.17 | 13.1 ± 0.44 | 19.9 ± 0.3 |
Based on the above discussions, the prepared Cd(II), Ce(III), Co(II), Cr(III), Fe(III), Ni(II) and Pb(II) complexes with (E)-N-(4-(2-hydroxybenzylideneamino) phenylsulfonyl) showing promising antimicrobial activity and the metal ions concentrations were determined using ICp-MS and gave a good agreement with the formula proposed which involved coordination of metal complexes in a regular octahedral arrangement in 2L:1M molar ratio by two N azomethine and two OH phenolic from the Schiff base {S.S} in the form of [ML2(H2O)2] except Ag complex was planner.
Ahmad SabryAbu-Khadra,Rabie SaadFarag,Alaa El-Dine MokhtarAbdel-Hady, (2016) Synthesis, Characterization and Antimicrobial Activity of Schiff Base (E)-N-(4-(2-Hydroxybenzylideneamino) Phenylsulfonyl) Acetamide Metal Complexes. American Journal of Analytical Chemistry,07,233-245. doi: 10.4236/ajac.2016.73020