Schiff base and complexe

مقدمة عن قواعد شف وطرق تحضيرها وتفاعلاتها وبعض تطبيقاتها

1. Wael AL-HARBI Schiff base complexes and application

2. INTRODUCTION Schiff bases constitute one of the most widely used families of organic compounds not only as synthetic intermediates but also in coordination chemistry and their chemistry is essential material in organic textbooks[1]. Schiff bases (also known as imine or azomethine), named after Hugo Schiff, was reported in the 19th century by Schiff(1864). Since then a variety of methods for the synthesis of imines have been described. The classical synthesis is when any primary amine condenses with a carbonyl compound[2].

3. INTRODUCTION Who was Schiff ? Born in the vibrant Jewish community in Frankfurt/ Main, Germany Revolutions these were tumultuous times in Europe Moved to London from Germany. Jailed. Because of his “rather advanced political views”. He emigrated to Switzerland He moved to Italy where his brother Moritz Schiff Spent his long career in Italy and continued teaching until 1915, the year of his death [3]

4. INTRODUCTION In Italy Schiff first obtained a position in Pisa, where in 1864 he studied the reaction of aniline with aldehydes, including acetaldehyde, valeraldehyde, benzaldehyde, and cinnamaldehyde. The first brief paper was entitled “A New Series of Organic Bases” [3].

5. INTRODUCTION Schiff base compounds have an azomethine group (-CH=N-) which are made by the condensation of carbonyl compounds with a primary amine [2]. But the Schiff base compounds that are prepared from aromatic aldehydes and aromatic amines are more stable and more effective [2].

6. INTRODUCTION The azomethane group (CH = N-) appears to be one of the reasons for making many types of base-base compounds of great importance in large areas of industrial applications and biological activities such as antimicrobial, antifungal, anticancer, antiviral, antioxidants, anti-inflammatory, antiparasitic , antioxidants and more in industrial and auricular chemistry [4]. These biological activities can be altered depending upon the types of substituents attached to the aromatic rings [5]. One of the most important alternatives is the hydroxyl group (OH).

7. INTRODUCTION Schiff bases containing hydroxyl group on different positions got a great interest because they have pharmacological activities for example anti-bacterial, anti-cancer and anti-oxidants. The Schiff base compounds, which contain a hydroxyl group in ortho, have two forms: Keto (N–H…O) and Enol (O–H…N) [6].

8. INTRODUCTION Of compounds known to the Schiff base containing a hydroxyl group salen and salophen. Although the Schiff bases are known to be good chelating agents, and easily prepared and characterized, little interest has been given to their uses for analytical purposes because of two serious drawbacks They are insoluble in aqueous solutions but soluble in most organic solvents They decompose easily in acidic solutions [7]

9. INTRODUCTION Schiff bases usually contain N, O and S donor atoms and may act as ligands. They are able to coordinate with many metals to stabilize their various oxidation states in such a way that a five or six membered chelate ring can be formed [8]. Schiff base ligands are easily synthesized and form complexes with almost all metal ions. Schiff bases and their metal complexes have been found to be biological active in the view of antibiotic, antimicrobial, antifungal and antitumor properties [8].

10. SYNTHESIS Four common methods that vary in reaction time, product, and percentage yield have been reported for the synthesis of Schiff bases. These methods include:

11. SYNTHESIS Four common methods that vary in reaction time, product, and percentage yield have been reported for the synthesis of Schiff bases. These methods include: Microwave method Stirring method Grindstone method Reflux method This method is temperature controlled method. Used to reduce reaction time and give high yield .

12. SYNTHESIS Four common methods that vary in reaction time, product, and percentage yield have been reported for the synthesis of Schiff bases. These methods include: Microwave method Stirring method Grindstone method Reflux method This is Green method of synthesis of Schiff bases. This is newly Developed process

13. SYNTHESIS Four common methods that vary in reaction time, product, and percentage yield have been reported for the synthesis of Schiff bases. These methods include: Microwave method Stirring method Grindstone method Reflux method This is conventional method for the preparation of Schiff bases. This Process gives the best yield and easy to form the product.

14. SYNTHESIS Four common methods that vary in reaction time, product, and percentage yield have been reported for the synthesis of Schiff bases. These methods include: Microwave method Stirring method Grindstone method Reflux method This is conventional method for the formation of Schiff base ligand

15. SYNTHESIS Time Yield Reaction condition Way 8 min 80.04% Microwave Irradiation 1 8 h 68.34% Reflux 2 5 h 75.12% Stirring 3 20 min 67.05% Grinding 4 [9]

16. SYNTHESIS R Scheme Synthesis Title 10 A solution of FeCl3·5H2O (1 mmol ) in 20 mL of ethanol was added dropwise to a solution of the ligand L2 (0.386 g, 1 mmol ) in 20 mL of ethanol with stirring. Non- enolisable Knoevenagel condensate appended Schiff bases-metal (II) complexes: Spectral characteristics, DNA-binding and nuclease activities 11 The following general procedure was applied in the synthesis of complexes [ NiL ] and [ CuL ]. 1 mmol of tetradentate Schiff base ligand dissolved in methanol (10 mL) was added to 1 mmol of acetate salt dissolved in 10 mL of a methanol. The resulting mixture was stirred at reflux for 2 h. Synthesis and electronic structure of novel Schiff bases Ni/Cu (II) complexes: Evaluation of DNA/serum protein binding by spectroscopic studies

17. SYNTHESIS R Scheme Synthesis Title 12 The La(III)/Th(IV) nitrate and vanadyl sulphate (4.3/5.7/1.81 g, 0.01 mol ) in super-dry alcohol (10 mL) were treated with Shciff bases (4.8/4.3 g, 0.01 mol ) in super-dry alcohol (40 mL). The reaction mixture was refluxed for 4–5 h. Synthesis, characterization, DNA cleavage and in vitro antimicrobial studies of La(III), Th(IV) and VO(IV) complexes with Schiff bases of coumarin derivatives

18. MECHANISMS

19. Spectroscopic properties FT-IR Spectra There are some functional groups that can be distinguished by absorption using the IR spectrum. One of the most important functional groups that can be distinguished in Schiff base compounds v(C=C) 1600-1580 cm -1 v(OH) 3400-3200 cm -1 v(C-O) 1100-1300 cm -1 v(C=N) 1610-1625 cm -1 [6]

20. Spectroscopic properties FT-IR Spectra It is observed that when Schiff base compounds are associated with metals, displacement of the absorption values occurs. New tetradentate Schiff bases of 2-amino-3,5-dibromobenzaldehyde with aliphatic diamines and their metal complexes: Synthesis, characterization and thermal stability Complexe Schiff base Compound C=N C=C C=N C=C 1458 1610 1627 1400-1500 L1 1604 1462 1633 1400-1500 L2 1605 1457 1632 1420-1500 L3 [13]

21. Spectroscopic properties FT-IR Spectra Synthesis, Characterization and Biological Studies of Metal(II) Complexes of (3E)-3-[(2-{(E)-[1-(2,4-Dihydroxyphenyl) ethylidene]amino}ethyl) imino ]-1-phenylbutan-1-one Schiff Base Schiff base Compound C-O C=N C=C 1241-1288 1605 1470-1543 DEPH2 1240-1287 1601 1469-1542 [Zn(DEP)].2H2O 1180-1240 1592 1483-1515 [Cu(DEP)].2H2O 1180-1240 1597 1485-11516 [Ni(DEP)].3H2O [14]

22. Spectroscopic properties UV-Vis Spectra In the UV-visible spectra of schiff base, Mostly the wavelength 200–400 nm is due to the π→π* and n→π* transition. In the UV-visible spectra of salicylaldimine and naphthaldimine derivatives, four main bands are to be expected in the 200–400 nm ; namely the first (210–234 nm) and second (240–282 nm) bands are attributed to the π → π* transitions of aromatic rings. The third band at 300–340 nm is assigned to the π → π* transitions of C=N group. The forth band at >400 nm involves n → π* transitions of C=O group [13]

23. Spectroscopic properties UV-Vis Spectra In the Schiff base complex, Beck's appearance is observed in the wavelength area> 400 depending on the type of metal bonded. Substitution of PPh3+ as a lipophilic cation on new water-soluble Co(II)and Zn(II) Schiff base complexes: Effect of central metal and substitutional group of ligand on DNA-complex interaction Wavelength {nm) Compound 333, 387 L 268, 382 1 268, 460 2 265, 380 3 265, 464 4 [15]

24. Spectroscopic properties UV-Vis Spectra In the Schiff base complex, Beck's appearance is observed in the wavelength area> 400 depending on the type of metal bonded New tetradentate Schiff bases of 2-amino-3,5-dibromobenzaldehyde with aliphatic diamines and their metal complexes: Synthesis, characterization and thermal stability Complexes Compound Schiff base Compound 484. 535 nm [NiL1]( OAc ) 2 364 nm L1 473 nm [NiL2]( OAc ) 2 362 nm L2 497 nm [NiL3]( OAc ) 2 363 nm L3 [13]

25. Spectroscopic properties X-ray Spectra Is a method to find out :

26. Spectroscopic properties X-ray Spectra 1 2 3 4 [16]

27. Spectroscopic properties X-ray Spectra 1 2 3 4 Compounds 1, 2, 3 and 4 crystallize in the monoclinic. Each of the molecules were found in the enolimine form. The crystal structures of 1, 2, 3 and 4 are stabilized by two intramolecular hydrogen bonds of the O–H…N . The crystal structures of 1, 2, 3 and 4 form weak stacking interactions between the aryl rings   [16]

28. Spectroscopic properties X-ray Spectra 3 In a compound 3 H–bonds are formed between the oxygen atom of the SO 2 group and the hydrogen atom of one of the spacer phenylene rings of a further molecule . As a result of these intermolecular interactions, polymeric chains are formed . [16]

29. Spectroscopic properties X-ray Spectra 1 2 3 4 [16] Indicates 4 3 2 1 Compounds single bonds 1.342(3)-1.342(3) C-O 1.413(3)-1.456(5) (N=)C-C (aryl) double bond 1.259(5)-1.302(3) (aryl)C=N sp2-hybridization of the nitrogen atoms 120.0(2)-122.22(19) C-N=C

30. Spectroscopic properties X-ray Spectra The molecules of 2, 3 and 4 contain two N- salicylidene aniline derivatives linked by an oxygen atom, sulfur atom or sulfone group with the dihedral angles for: Compound 2 : C6H4–O–C6H4 53.72(8) Compound 3 : C6H4–(O=)S(=O)–C6H4 80.66(10) Compound 4 : C6H4–S–C6H4 73.63(10) [16]

31. Spectroscopic properties X-ray Spectra Molecules of 2, 3and 4 are stacked in the crystal However, in 3 each of the N- salicylidene aniline residues of a molecule are packed almost perpendicularly to two N- salicylidene aniline derivatives of a further molecule [16] 3

32. Spectroscopic properties X-ray Spectra whereas in 2 and 4 N- salicylidene aniline residues of a molecule are parallel [16] 4 2

33. Spectroscopic properties X-ray Spectra

34. Spectroscopic properties X-ray Spectra 1 2

35. Spectroscopic properties X-ray Spectra 1 The asymmetric unit of compound 1 contains one half of the molecule The phosphazene ring (P1/N1/P2/N2/P3/N3) The six-membered rings (P1/N7/O1/C1/C6/C7)

36. Spectroscopic properties X-ray Spectra 1 The phosphazene ring (P1/N1/P2/N2/P3/N3) θ2 = 123.3(1.8)° twisted-boat conformation

37. Spectroscopic properties X-ray Spectra 1 The six-membered rings (P1/N7/O1/C1/C6/C7) θ2 = 89.39(13)° boat conformations

38. Spectroscopic properties X-ray Spectra 2 The phosphazene ring (P1/N1/P2/N2/P3/N3) and (P4/N4/P5/N5/P6/N6) The six-membered rings (P1/N7/O1/C1/C6/C7) and (P4/N8/O2/C21/C22/C23)

39. Spectroscopic properties X-ray Spectra 2 The phosphazene ring (P1/N1/P2/N2/P3/N3) θ2 =93.4(1.1)° twisted-boat conformations (P4/N4/P5/N5/P6/N6) θ2 = 89.4(1)° boat conformations

40. Spectroscopic properties X-ray Spectra 2 The six-membered rings (P1/N7/O1/C1/C6/C7) θ2 = 89.39(13)° flattened-boat conformations (P4/N8/O2/C21/C22/C23) θ2 =144.23(49)° boat conformations

41. Spectroscopic properties X-ray Spectra

42. APPLICATIONS Biologically active A series of Schiff base derivatives were synthesized and analyzed as novel antioxidants and anti-inflammatory agents [17]. [17]

43. APPLICATIONS The in vitro antioxidant activities of these compounds were evaluated and compared with those of commercial antioxidants: ascorbic acid, gallic acid, butylated hydroxytoluene and butylated hydroxy anisole (BHA) employing 1,1-diphyenyl-2-picrylhydrazyl (DPPH) assay. The results 1-revealed that IC 50 values of compounds were lower than those of standards in all three performed antioxidant assays indicating good activities of these compounds. 2-That the compounds with electron-donating moiety (OH, OCH 3 ) were found to be excellent antioxidants. 3-That the compounds with electron-withdrawing moiety (Cl, NO 2 ) were found to be excellent anti-inflammatory agents. [17]

44. APPLICATIONS Catalysis Schiff bases are artificial and are used to form many important catalysts, such as  Jacobsen's catalyst . One of the uses of this catalyst is preparation of epoxidation

45. APPLICATIONS [18]

46. REFERENCES

47. REFERENCES

48. REFERENCES