Chapter 2

Page 37

Chapter 2

Literature Review

Chapter 2

Page 38

2.1 Literature Survey of Schiff Bases and Metal Complexes

It has vital part in improvement of inorganic chemistry and has taken extensive place

in coordination chemistry, biochemistry and environmental chemistry. Schiff bases

have a chelating structure and are in demand due to their straight forwardness to

synthesize and are moderate electron donors with effortlessly tunable electronic and

steric effects thus being flexible. These types of complexes with heavy metals and

transition are used in organic synthesis, medicine, analytical reagent, and metal ion

catalyst [208-210].

Because of high potential permutations Schiff bases have been broadly studied.

Weight determination, Magnetic susceptibility, elemental analysis, molecular,

conductivity, absorption spectrum and thermal analysis of lots of Schiff bases and

their complexes have been informed. A number of workers have reported that the

quickly developing field of bioinorganic chemistry is centered in the existence of

coordination compounds in the living systems [211,212]. In the 1860s the general

synthesis of Schiff bases and reports of metal complexes of these types of ligands

were former published. [213-215].

In many biochemical reactions Imines play an important role. Because a few of the

enzymes make use of n amine group of an amino acid to react with an ketone or

aldehyde to form an imines’ linkage [216], Where R might be an aromatic group or

aliphatic group.

Schiff bases of aromatic aldehydes, having an effective conjugation system, are more

stable while aliphatic aldehydes are relatively unstable and are readily polymerize.

Condensation of amines with ketones and aldehydes has several applications which

contain detection, preparative use and determination of aldehydes or ketones,

purification of carbonyl or amino compounds, or protection of these groups for the

duration of complex or sensitive reactions.

Chapter 2

Page 39

Because of high synthetic flexibility the chemistry of Schiff base is studied broadly

various medicinal utility and co-ordination ability. These compound Contain >C=N

group and are also known an azomethine or as an imine but are normally known as

SCHIFF BASE to honor Schiff [217].

Werner who organized the subject by put forward in his coordination theory in

1893[218] on the basis of old history which was the invention of [CO(NH3)6]CI3 by

Tassaert in 1798[219]. Werner’s basic thoughts on racemisation, mechanisms of

isomerization and the stereochemistry of metal complexes, etc. stay unchallenged

even today regardless of all the immense developments which have taken places

since his days and through the last five decades in particular, yet to be paid the

initiation of sophisticated physico chemical techniques of high accuracy and

capability [220, 221]. The nature of structure and stereochemistry of metal

complexes, the metal-ligand bond, stabilities and liabilities of them and other

properties have noticeably enhanced our understanding. As the alkali metal

complexes shaped by crown ethers and cryptates [222-225], the metal are now

acknowledged forming moderately stable complexes with special types of ligands

which were previously thought to be non-complex formers.

As per Werner [226] atoms, acquire two types of valency is principal, primary or

auxiliary valency and secondary or residual valency. While usual molecules results

from the satisfaction of primary valencies, use of the secondary valences lead to the

form of coordination compounds [227]. During the last 50 years, a study of the

literature shows that as well examine problems of electronic structure, stabilities of

metal complexes, bonding and stereochemistry of metal complexes and, an

increasing number of studies have been dedicated to mechanisms and dynamics of

reaction of metal complexes[228-233]. The classical application of complex creation

in analysis and other laboratory practices have been refined and sophisticated to such

a degree that it is now likely to monitor concentration of species at amazingly low

level. [234].

Chapter 2

Page 40

As per the current theory, even the organ metallic compounds belong to the common

class of coordination compounds, and a host of such compounds of a huge majority

of metal have been synthesized with extensive range of organic substrates. Apart

from their academic implication, these are of vast technological consequence because

of their helpful catalytic properties [235, 236]. furthermore, the application of metal

complexes also have an older history, and lots of complex preparation reactions are

in use since previously for the separation, detection and judgment of metals both in

macro and micro scales. A few Metal complexes might be observed in the photolytic

splitting of water producing hydrogen additional current and somewhat exciting

applications of it. Due to non-availability of remnant fuels this method has immense

potential which might be crucial solution to save the world from a severe crisis in the

future for producing a nonpolluting fuel An additional vital development is the

recognition of the very important role of metal complexes in biological

systems[237,238], Both in biological systems and their applications in the technology

and in laboratory a knowledge of the factor that govern the reactivity and stabilities

of metal complexes could be of vast help in understanding the activities of metal

complexes. It is the information of the environment of the metal-ligand bond which

provides a fundamental basis for accepting the actions of metal complexes. In the

field of therapy there are significant uses of metal complexes and of complex

formers. Dates back to 1917 the gold complexes used in the treatment of tuberculosis

and in the treatment of arthritis [239]. Though numerous important developments

have taken place in last 30 years in the field of application of metal complexes in

medicine and biology [240-242]. The case of metal poisoning in lots of the

complexes formers and complex are familiar to be used as drugs in certain types of

diseases as in addition for metal detoxification [243,244].

In few pages the studies on co-ordination compounds have become incredibly

extensive and it’s not possible to describe. The central metal ion is bounded to

diverse Ligands show signs of diverse characteristics properties in co-ordination

compounds. The characteristics of such compounds are based on nature of the type of

ligands and their structures as well as metal. Metal complexes which having organic

Chapter 2

Page 41

molecule in the physiological systems take part in key role to the formation,

existence growth and maintenance of whole human being and as a result the current

research activity phosphorus, nitrogen, oxygen and sulphur containing organic

molecules are very important components of physiological system and therefore

Complexation studies of organic compounds having these atoms established

particular interest by coordination chemists [245-247].

The chemistry of the metal complexes of Schiff bases having nitrogen and other

donors has been paid considerable awareness in last two decades [248-254]. Schiff

bases recommend a flexible and versatile series of ligands able to bind with a range

of metal ions to provide complexes with appropriate properties for practical and/or

theoretical applications. Seeing as the publication of Schiff base complexes, a huge

number of polydentate Schiff base compounds have been extensively investigated

and structurally characterized. This may be credited to , biological activity, stability

and potential applications in various area such as, electrochemistry, oxidation cataly-

sis etc. The subject of great interest is the study of relationship between the metal

ions and their metal complexes as antibacterial and antitumor agents. More than 25

inorganic compounds being used in therapy as antiviral, anticancer and antibacterial

drugs which field was initiated by the inorganic pharmacology [255-264].

Gheorghe, et al., (2001) had most important focus on twenty new Schiff bases resulting

in the presence of catalytic amounts of sulfuric acid from ortho- hydroxy aldehydes and

hetroaromatic or aromatic amines have been prepared in high yields via condensation in

ethanol. These useful as ligands, azomethines, intermediates in organic synthesis or latent

biologically active substances, have been characterized by IR, 1H and 13C NMR spectra

and elemental analysis.[265]

Chapter 2

Page 42

Figure 2.1

Chapter 2

Page 43

Iqbal, et al., (2009) had chief focus on neutral complexes of Cu(II),Ni(II), and Co(II)

with a Schiff base resulting from sulfonamide and benzaldehyde have been prepared

and characterized the basis of on UV -VIS, FTIR , atomic absorption spectroscopic

data and molar conductance. Against two bacterial species E.coli these metal complexes

were screened for their antibacterial activity. [266]

Joshi, et al., (2010) had key focus on Schiff base and its metal complexes preparation by

Condensation of p-Chloro benzaldehyde and vanillin with Trimethoprim correspondingly

in methanol. Additional their metal complexes have been prepared by metal salts of Ni

(II), Mn (II), Co (II), and Zn (II) were Characterized by UV, IR, Elemental analysis and 1HNMR spectral data. The Schiff base and its complexes were compared with the

standard antibiotic oflaxocin and their in vitro growth inhibiting activity against different

strains of bacteria viz., gram positive Staphylococcus aureus, Bacillus licheniformis,

Micrococcus lutes and gram negative Escherichia coli. [267]

Joshi, et al., (2011) had main focus on a little of new Schiff bases derived from the

cinnamaldehyde and p-chloro benzaldehyde with aldehydes and amoxicillin trihydrate

and their complexes with bivalent transition metal exe., Co (II), Ni(II), Mn (II) and

Zn(II). They were screened for antibacterial activity against numerous bacterial strains

namely E.coli (-), M.luteus (+), S.areus (+) and B licheniformis(+)(ATCC). The metal

complexes demonstrated improved antibacterial activity evaluate to uncomplexed ligand

[268].

Joshi, et al., (2011) studied on condensation of p-chloro benzaldehyde and

cinnamaldehyde with cephalexin correspondingly in methanol. By copper, nickel, zinc

and manganese the complexes were prepared. Through TLC, IR, UV, 1H NMR, molar

conductance characterization of the components were done. With gram positive and gram

negative bacteria the synthesized compounds were checked for its antibacterial activities.

[269].

Chapter 2

Page 44

Figure 2.2

Chapter 2

Page 45

Figure 2.3

Khosa, et al., (2011) had main focus on three novel series of biologically active amino

substituted Schiff bases in ethanol with R1N = CHR2 (R1 =4-amino-salicylic acid, 2-

amino-benz thiazole and 4-amino phenol: R2 = benzaldehyde, salicylaldehyde, 2-cholro

benzaldehyde and vanillin). By different physic-chemical techniques the synthesized

compounds were characterized. Using Amoxicillin and Ciprofloxacin as standard drugs

the Compounds showed promising antifungal and antibacterial activities [270].

Figure 2.4

Chapter 2

Page 46

Figure 2.5

Figure 2.6

Chapter 2

Page 47

Mashaly, et al., (2004) had focus on a sequence of biologically active mononuclear

complexes of Co (II), Zn (II), Ni (II) and Fe (III) was synthesized. In the presence of

LiOH, the reactions of the Schiff base ligand 1-phenyl-2, 3-dimethyl1-4, salicylalidene

pyrazole-5-one with the previous metals. The binary complexes respond with the mixed

ligand 2-aminopyridine, 8-hydroxyquinoline and oxalic acid to figure the mixed ligand

complexes. All the mixed and binary ligand complexes have octahedral configurations.

Their structures were clarified by, conductance, elemental analysis, IR, magnetic

moments, 1H NMR and TG-DSC measurements [271].

Figure 2.7

Chapter 2

Page 48

Figure 2.8

Chapter 2

Page 49

Figure 2.9

Chapter 2

Page 50

Figure 2.10

Figure 2.11

Chapter 2

Page 51

Naz, et al., (2009) had discussed on Ni(II),Co(II), and Fe(II) metal complexes of

innovative Schiff bases resulting from amoxicillin with sugers (D-Glucose and D-

mannose) have been prepared and characterized by , electronic absorption, element

analysis, FTIR, and aromatic absorption spectroscopy. Every complexes have superior

biological activities than pure amoxicillin [272].

Figure 2.12

Chapter 2

Page 52

Figure 2.13

Chapter 2

Page 53

Bayer reported the broad exploration in the field of Schiff bases. Layer reported their

synthesis, chemical and physical properties [273].

A few methods for the preparation of Schiff bases have been described by Dayagi

and Degani [274].

Because of the vital ability and various structure Schiff base feature, wide range of

Schiff base compounds and their metal complexes have studied and synthesized. By

condensing or fusing the synthesis of the Schiff base occurred which is described by

Jura and Scott.

Different infrared spectra of Schiff bases have been considered. The obtained rage of

the IR frequency for the Ar-CH=N-Ar of Schiff base is 1630 to 1615 Cm-1

distinguished by Cloughertyet et al. An absorption band for the alkyl Schiff base

RCH = N-R’ was in range at 1681-16667cm-1 which have been studied by Steele.

Aliyu, et al., had main focused on Schiff base derivatives from a few aliphatic

diamines and 2-hydroxy-1-napthaldehyde has been characterized and synthesized.

Copper complexes were formed from each Schiff base ligands, the elemental

analysis, molar conductance, temperature decomposition, solubility, U.V and IR was

taken. In complex’s elemental analysis the metal ratio to ligand is 1:1 for C, N and H.

Antifungal and anti microbial activities were done. [275]

Babu, et al., (2004) had main focused on synthesis, characterization of novel Schiff base

of Tris (hydroxy methyl) methyl amine-vanillin. The detailed study of polarographic for

the complexes in lead ion is present here. [276]

Bairagi, et al.,(2009) had main focus on various anilines and 4-Chloro-2-oxo-2H-3-

carboxaldehyde in solvent like rectified spirit for yield to a title compounds series viz.,4-

chloro-3-((substituted phenyl imino) methyl)-2H-chromene-2-one. On the spectral data

base IR and 1H NMR the compounds was characterized and estimated for in vitro

Chapter 2

Page 54

activity again to fungi and gram negative bacteria. Most active compound found in MIC

of 15 ug/ml again all organisms tested. [277]

Deshpande, et al.,(2013) had focus on the synthesis of 12 Schiff bases complexes has

been discussed, By Pyridine 2-carboxaldehyde, pyrrole 2-aldehyde with 2-amino-4,6-

dimethyl Benzothiazole condensation Schiff bases are observed, and Mn (II), Ni(II),

Cr(II),Cu(II),Fe(II) and Cu(II) chloride were chosen to synthesized novel metal

complexes. On the basis of mass NMR and IR study the Schiff base and metal complexes

characterized. The Schiff base and its metal complexes were shown antibacterial activity

with a variety of bacteria. [278]

Figure 2.14

Figure 2.15

Chapter 2

Page 55

Dey, et al., (20010) had synthesized a innovative Schiff base which is N-2-[3’-(methoxy

salicylidene imino) benzyl]-3-methyl salicylidene imine (I) through the reaction of 3-

methoxy salicylaldehyde and 2-amino-1-amino benzyl amine with use of ethanol. With

single crystal XRD the molecular structure was defined. [279]

Geronikakai, et al., (2003) had designed various novel thiazolinyl; benzo thiazolyl and

thiazolyl contain Schiff bases. The Schiff base has been reported and performs as

lipoxygenase inhibitors which affect psoriasis or inflammation. The compounds were

defined as reducing activity and as soya beans lipoxygenase inhibitor. By paw oedema

technique was used for check in vivo activity. [280]

Jayabalakrishnan, et al., (2002) had synthesized Schiff bases through condensation by O-

aminophenol and O-amino thiophenol with O-vanillin or salicylaldehyde in attempt to

acquire various ruthenium complexes. [281]

Jayshree et al., (2004) had prepared Schiff bases react various aldehydes with 2-amino-4-

(3-coumarinyl) thiazole. Many of Schiff bases show an anti-inflammatory and analgesic

activity. [282]

Kam, et al., (2001) prepared 1:1 and 1:2 Schiff bases derivatives by O-vanillin and 2,3-

diaminopyridine and with eight metal complexes of them. These ligands and its

coordinated compounds exhibit the antibacterial activity. [283]

Khan, et al., (2002) synthesized the Schiff bases from isatin. The compounds evaluated

analgesic activity. The ligands have less analgesic activity than aspirin comparatively.

[284]

Khan, et al., (2002) Prepared isoniazid Schiff base which is for their anti bacterial activity

use as test organism like Staphylococcus aureus. The inhibition zone was checked by

using standard as amikacin. [285]

Chapter 2

Page 56

Kulkarni, et al., (2012) had studied 15 novel complexes of lanthanides of Schiff base

which are shown, the Schiff bases were synthesized through condensing 2, 5-di hydroxy

acetophenone, pyridine 2-aldehyde with 2 amino 4, 6-dimethyl Benzothiazole, and

lanthanide chlorides were preferred to prepare novel complexes. These metal complexes

were selected for antibacterial activity, antimicrobial activity against E-coli, s-aureus like

bacteria and A-Flavus and A-Niger like antifungal activity. [286]

Mittal, et al., (2009) had synthesized and characterized metal complexes of analytical,

physical and spectral data. The recently prepared metal complexes had a composition

M(LX) 2Y2 where M = Mn (II), Ni (II), Co (II) and Cu (II), LX = bidentate ligand Y = Cl

demonstrated octahedral type geometry, The Schiff bases and its metal complexes was

screen for its antifungal and anti bacterial activity. [287]

Mobinkhaledi, et al., (2010) synthesized few of new Schiff bases with easy and effective

method by reaction between 2- amino benzaldehyde with aromatic aldehydes in organic

solvent with catalytic quantity of M(NO3)2.xH2O at ambient temperature. This little

compensation gives better yields by using catalysis, fast reaction and easy to work up.

[288]

Mohan, et al., focused on thirty novel Schiff bases with ten aromatic aldehydes and 2-

amino-3-(N tolyl carboxamido)-4,5- trimethyle thiophenes. From these some Schiff bases

showed good antibacterial activity. [289]

Naik, et al., (2004) prepared some of Schiff base from heterocyclic compound, through

aldehydes and 2-amino-4-(3-coumarinyl) thiazole and then react compounds with chloro

acetaldehyde. For antibacterial activity they are screened. [290]

Chapter 2

Page 57

Ndahi, et al., (2012) synthesized the Schiff bases with 2,4-di nitro phenyl hydrazine or

anisidine and 4- anisaldehyde by condensation reaction. By electronic spectra elemental

analysis, molar conductance and infrared spectra have been characterized. Against few of

pathogenic bacteria like Pseudomonas aeruginosa, Bacillus subtilis, Escherichia coli,

Staphylococcus aureus and salmonellatyphi the compounds were measured in vitro study

for antibacterial activity by agar-well diffusion technique. [291]

Figure 2.16

Chapter 2

Page 58

Paneerselvam, et al., (2005) had synthesized derivative of Schiff bases from 4-(4- amino

phenyl) morpholine and checked antibacterial and also antifungal activity. All

compounds shows good activity. [292]

Patil, et al., (2012) done reaction of aryl aldehyde with primary aromatic amine with

catalytic amount of lemon juice use as natural acid in solvent free condition with good

yield correspondingly. This reaction is eco friendly and very much economic; condition

of the reaction is mild, easy work-up and environment friendly along with great yield of

product. [293]

Prakash, et al., (2011) had focus on Synthesize flexible Schiff base ligands from

condensation of compound containing carbonyl and amino group. The Schiff base and its

metal complexes are vital and use as catalysis, dyes, polymers and pharma and medical

fields. Also they are useful in food industry, in birth control and ass O2 detector. This is

described the use of Schiff base and its metal complexes. [294]

Saxena, et al., (2012) work on the Schiff base ligand was synthesized with 4-amino 5-

mercapto 5-triazole and furfuraldehyde and also characterized. With molar conductance,

IR, 1H NMR elemental analysis, magnetic measurement and by electronic spectral data of

V(III), Ru(III), Ti(III) and Co(III) prepared from the ligand were synthesized and

characterized. By the study these metal complexes octahedral structure assigned. [295]

Sheeja, et al., (2012) synthesized metal complexes of Ni (II), Zn (II), Co(II) and Cu (II)

which was synthesized with tryptophan and 4-pyridine carboxaldehyde. By UV and IR

The complexes are characterized also the study of its DNA cleavage and microbial

activity have been carried out. The ligands and its complexes demonstrated promising

activity again Pseudomonas aeruginosa, Klebseilla pneumonia, Staphylococcus aureus,

Escherichia coli, fungi and Proteus, Aspergillus Niger. [296]

Shetty, et al., (2004) had focus on preparation and evaluation of the antibacterial study of

30 new Schiff bases prepared with 2-amino-3-(N chlorophenyl carboxamido)-4,5-

Chapter 2

Page 59

dimethyl thiophenes. The ligands were prepared through condensation of 10 differ

aldehydes. [297]

Shijun, et al., (2002) had prepared 30 novels hydroxy semicarbazide Schiff bases Ar-CH-

NHCONHOH where Ar = 5-nitro 2-thienyl, CF CH, etc. These are checked against

murine leukemia L1210 cells. By QSAR analysis the pharmacophor which necessary is

NHCONHOH, portability/size of molecule, hydrophobicity and having group which

contain oxygen in the ortho position from there the antitumor activity is significant. [298]

Singh, et al., (2002) synthesized new Schiff base from anisaldehyde, indol

carboxaldehyde, Acetophenone and O vanillin through condense with 4-amino 3-

mercapto 6-methyl 5-oxo 1,2,4-tiazine.The Schiff bases was synthesized for the attempt

to prepare novel complexes by nickel, zinc, cobalt and copper. [299]

Singh, et al., (2003) had prepared ligands derivatives with nucleophillic addition of 2-

pyridine carboxaldehyde, O-vanillin, p-nitro benzaldehyde and O-nitrobenzaldehyde

towards 4-amino 3-ethyl 5-mercapto 5-triazole and 3-ethyl4-amino 5-mercepto 3-mesyl

5-triazole. By copper, nickel, zinc and cobalt bivalent metal complexes were synthesized

through Schiff bases synthesized. [300]

Sun, et al., (2001) prepared 4 Schiff bases from dl- amino acid ands and O-vanillin by

quantum chemical techniques and dynamic analytical techniques. [301]

Suresh, et al., (2011) studied on novel series of Cu(II),Co(II),Zn(II),Ni(II) and Mn (II)

metal complexes which were prepared through new macro cyclic ligand along with 4 N

donor derivatives with O-phenylenediamine and vanillin,4-amino antipyrine. Many of the

instruments analysis such as molar conductance, UV, IR, ESR and NMR, elemental

analysis, TGA spectroscopic techniques were help to identify the chemical structure of

synthesized ligands and its metal complexes. [302]

Chapter 2

Page 60

Suresh, et al., (2004) focused on new bidentate ligands which prepared with vanillin and

4-amino antipyrine to figured stable metal complexes with metal ions like Ni(II), Cr(III),

Mn(II), Cd(II), Cu(II) and Zn(II). Structure of them was identified by IR, NMR, ESR,

TGA, electronic spectroscopy and elemental analysis. [303]

Thorat, et al., had work on nitrated vanillin through use process of literature 3-methoxy 5

4-hyroxy 5-nitrobenzaldehyde. By the well known literature process of Vogel 5th addition

for organic chemistry practical the Schiff based were prepared with use of halogen

substituted anilines. Because of the reactivity of nitro vanillin to amines the formation of

4-{(E) [(4- aryl) imines] methyl} 2-methoxy 6-nitrophenol and study for the fluorescence

was occurred. [304]

Vaghashiya, et al., (2004) derived Schiff bases from vanillin and 4-1-phenyl 2,3-

dimethyl-4-aminopyrazol-5-one which shown ability of antibacterial agents in front of a

few gram negative and positive strains of bacteria. The activity was done in two solvents

like Dimethyl formamide and Dimethyl sulphoxide which are very polar. Schiff base

synthesized having vanillin with sulphamethoxazole and 2,4-dimethylaniline in DMSO

efficiently inhibit the bacteria and shows potential antimicrobial agents. [305]

Venugopal, et al.,(2004) prepared bromo thiazolyl amino coumarin Schiff bases from

different aromatic aldehydes with 2-amino 4-(6-bromo-3-coumarinyl) thiazole. The

ligands show anti inflammatory and analgesic activities. With presence of some

functional group few compound shown exciting biological activities. [306]

Vinci, et al., (2003) concentrated to prepare 3 novel series from thiazole and benzo (d)

isothiazole ligands which shown the anticancer and antiviral which is not definitely cure

presently. The compounds illustrated noticeable cytotoxicity in front of CD4+

lymphocytes (MT 4) which used to carry the growth of HIV-1. These compounds inhibits

leukemia cells growth and from them one compound exhibit anti proliferative activity

that shown by the results. [307]

Chapter 2

Page 61

Wang, et al., (2002) prepared 12 novel Schiff bases having 5-amino 1H 1, 2, 3, 4-

tetrazolyl. The Schiff bases transformed in α–(5-tetrazolyl) amino alkyl phophonate

through treat it with (EtO)2 P O H outcome of the biological study described few of

compounds have noticeable plant expansion variable activities. The majority of Schiff

bases which active were synthesized from 3-formyl indole and Chlorobenzaldehyde.

[308]

Zakrzewski, et al; (2003) had prepared the derivatives of N-benzylidene -4(4,5 –dipheny1

1H- imidazole -2y1) anilines and invent the fungal activity in front of six microorganism.

[309]

Zhu, et al., (2003) synthesized Schiff base from salicylaldehyde, O-vanillin with 5-

Mercapto 2-amino, 1, 3, 4-thiadiazole and the molybdenum complexes of it. Their result

on the continued existence cell ratio of spout in beans has been examined. [310]

Bharte, et al., (2010) searched on drugs compatibility signifies a vital stage in the

formulation phase of growth of every dosage form. The probable chemical and physical

relations among excipients and drug may influence on chemical environment, the bio

avaibility and stability of drug and, their therapeutic safety and ability. At the time when

the pharmaceutical system’s of solid phase reaction comes in understanding, the essential

steps could be carried out to concern the reactivity and get better the stability of product

and drug substance both. [311]

Iqbal, et al., (2005) has been studied on Co(II) and Zn(II) Schiff base complexes of

cephalexin and amoxicillin with pyridoxal, salicylaldehyde were synthesized and

characterized TGA and spectral and magnetic data. Above every complex shows

coordination with the six molecules which includes two molecules of water. The Zinc

complexes show octahedral geometry. The compounds are giving promising activity

towards bacterial study. Activity of drug taken for Schiff base synthesis is negligible than

all synthesized complexes. [312]

Chapter 2

Page 62

Figure 2.17

Figure 2.18

Chapter 2

Page 63

Chandramohan, et al., (2012) studies the condensation reaction of amine with aldehydes.

The purpose of the study is to condense 3 aromatic aldehydes like 4-hydroxy

benzaldehyde, ethyl vanillin and vanillin with Trans amino cyclohexanol to prepared

Schiff bases. Objective of the work is prepared Schiff based. Objective of the work is

prepared Schiff base from allyl bromide and epichlorohydrin by O- alkylation and it was

characterized by IR and 1 H NMR. [313]

Chatterjee, et al., (1990) prepared Schiff base ligands through condensation of 4-phenyl

Thiosemicarbazide and 2-furfuraldehyde or vanillin. With the reaction of Schiff base and

metal salt obtained ML2HO.M coordinate by thiol’s S and azomethines N. By the basis

of different analytical techniques the octahedral structure were planned. [314]

Nicolae, et al., (1990) studied Schiff bases through the reaction of 5- formyl vanillin,

with aromatic 3-amines such as aminopyridine, un substituted anilines and 1 or 2

naphthylamine. More than 80% yield obtained. [315]

Hiroshi, et al., (1991) synthesized numerous Schiff bases of cumin aldehyde,

benzaldehyde, perillaldehyde and hydroxyaniline, aniline with vanillin, and N-

acylated amino acid and D-glucosamine and derivative via theronine, serine and

organic acids like camminic acid, perillic acid, phenyl acetic acid, ferulic acid,

vanillic acid and trans-cinnamic acid is test less, nearly everyone along with the

unprotected C-terminus given a sour taste and with the protected C-terminus contain

a bitter taste. [316]

Oza, et al., (1998) prepared 30 new thiazolidinone compounds through cyclo

condensation with thioglycollic acid and 2,4,6-thiolactic acid were potent anti

tubercular agents. Against tuberculosis like mycobacterium the synthesized

compounds showed anti-tubercular activity. [317]

Zhou, et al., (1999) studied many of Schiff bases in the lake of solvents. The

procedure shows the mixing of amine such as aniline p-phenylenediamine, 4 amino

Chapter 2

Page 64

antipyrine, p-chloro aniline, semicarbazide HCl and p-methyl aniline with aromatic

aldehyde such as o, m and p-hydroxy benzaldehyde, o, m and p- nitrobenzaldehyde

and p-methoxy benzaldehyde. Acid catalysis such as phenolic acid, sulphonic acid

and phenolic acid was use in catalytic amount. [318]

Rathod, et al., (2000) condensed 2-furfuraldehyde and in different way substituted

benzaldehyde with 2-amino 4-methyl Benzothiazole, 2-amino Benzothiazole,2-

amino 6-methyl benzaldehyde, and 2- amino 4-phenyl thiazole and prepared Schiff

bases. Against gram negative and gram positive these compound gives good

antibacterial activity. [319]

Yuan, et al., (2000) prepared 8 novel Schiff bases from substituted benzaldehyde and

5-amino triazole-3-carboxylates which having 1H Et 1, 2, 4-triazole-3-carboxylate

[320]

Murthi, et al., (2000) have studied Schiff base by benzene as a solvent, o-toluidine/p-

toluidine, aniline with o-vanillin. The ru(III) complexes of these Schiff bases were

prepared and studied against Aspergillus niger pathogenic fungi and fusarium sp.

[321]

Wang, et al., (2000) studied on condensation of o-vanillin and DL-alanyl DL-alanine.

The synthesis and characterization of the cobalt, nickel, copper and zinc complexes

were carried out. [322]

Gong, et al., (2000) had synthesized 5 different Schiff bases by substituted

benzaldehyde and 4-amino antipyrine. The Schiff bases show 16 to 320 times more

fluorescence intensity than 4-amino antipyrine. [323]

Wu, et al., (2000) done reaction of vanillin aldehyde and chitosan in water and

prepared Schiff base. The reaction was dependent on reaction’s temperature, time

and concentration. [324]

Chapter 2

Page 65

Yuli, et al., (2000) prepared bis phophonate which was phenol substituted with

substituted benzaldehyde and nitro aniline through reduction and condensation and

its antitumor activity were checked. The antitumor activity was depended on the

place of phenolic hydroxyl group which was next of double bond. This Schiff base

was shows more effectiveness than other. [325]

Shakih, et al., (2001) have prepared Schiff bases with Benzothiazole having

substitution in 2nd position. The compounds were prepared and checked antifungal

and antibacterial activities. [326]

Mohan, et al., (2002) prepared 30 Schiff bases with 10 substituted aromatic

aldehydes and 2 amino (3-N tolyl carboxamido) 4,5-tromethylene thiophenes. From

that few Schiff bases showed nice antibacterial activity. [327]

Sleema et al., (2002) et al., have done condensation between L-histidine and o-

vanillin and prepared Schiff bases under reflux condition. The complexes of the

compounds prepared by Co, NI, Cu and iron and studied of X-ray diffraction [328]

Yanhong, et al., (2003) studied on amino acids and o-vanillin Schiff bases and their

metal complexes which having inhibit ability. [329]

N. K. Chaudhary., (2013) synthesized novel ligands with pyrrole 2-carboxaldehyde

and Amoxicillin trihydrate under reflux condition with use of Aq. Methanol and

catalytic amount of acid. The metal complexes prepared with copper, zinc and cobalt

chloride and characterized by 1H NMR, IR, elemental analysis and mass. The Schiff

bases and their metal complexes showed antibacterial activity in front of bacteria like

B. subtilis, S. aureus and E. coli, where amoxicillin trihydrate used and the inhibition

zone was measuring in diameters. Results shown the metal complexes give good

activity than ligand and Amoxicillin trihydrate. [330]

Chapter 2

Page 66

Figure 2.19

Figure 2.20

Chapter 2

Page 67

Figure 2.21

Taghreed, et al., studied Novel ligand (E)-6-{2-[4-(Dimethyl amino) benzylidene

amino]-2-(4-hydroxy phenyl) acetamido}-3,3-dimethyl-7-oxo-4-thia-1-aza bicyclo

[3,2,0] heptanes 2-caboxycillic acid prepared with condense 4dimethyl amino

benzaldehyde with amoxicillin in methanol as solvent. As per figure the mixed

polydentate legend’s complexes were found with 1:2:1 mole ratio. The formula of

resultant complexes is ML(NA)2 Cl. Whereas M is Copper, Nickel, Zinc and Iron

while A is nicotinamide.

Chapter 2

Page 68

Figure 2.22

The Schiff base was characterized by using elemental analysis, UV, IR, and 1H

NMR while the metal complexes were characterized by UV, IR, atomic absorption

spectroscopy, magnetic susceptibility, chloride contains by conductance. In Dimethyl

sulphoxide all metal complexes were non electrolytes. For every metal complexes

octahedral geometry has been obtained. The ligands shown as tridentate and for the

coordination enolic form is suggested. Bacterial activities of the Schiff base ligand

and its complexes have been determined. [331]

Chapter 2

Page 69

Figure 2.23

Srivastava et al., has prepared novel, quick, component, clear, environment friendly

Schiff base and its complexes interestingly. The Schiff bases prepared by

sulphamethoxazole, Amoxicillin, Trimethoprim and Cephalexin with pyridoxal and

its metal complexes were prepared by Zn (II), using catalytic amount of alkali and

obtained good yield in microwave synthesis. This method gives benefits like

environmentally, small time for reaction, small time for the reaction, easy for work

up, safe and provides nice yield. Comparison of conventional method and

microwaves method for the time and yield were studied. The characterization was

done by TGA, Spectroscopic and magnetic study, micro analytical techniques. All

synthesized ligands were found bidentate while complexes showed coordination with

six molecules. Complexes are more stable in air and colored. Every compound

Chapter 2

Page 70

shown antibacterial activities which is greater in metal than ligands then drug choose.

[332]

Figure 2.24

Figure 2.25

Chapter 2

Page 71

Malik, et al., Synthesize and characterize Schiff bases and its metal complexes

prepared from diuretic drug xipamide. The condensation of salicylaldehyde and

xipamide was taken in 1:1 ratio for synthesis of bidentate Schiff base. By this ligand

and metal complexes of Zn (II), VO (IV) and Hg (II) were synthesized.

Characterization of this compound was done with IR, mass, elemental analysis,

molar conductance, particle size and by magnetic susceptibility. Elemental analysis

indicates the ratio of the metal complexes and ligand is 1:2. Molar conductance

suggest all complexes are non electrolytic. IR proposed the coordination behavior

among metal ion and ligand by the deprotonation of phenolic oxygen. The geometry

of the VO (IV) complexes is square pyramidal and Zn (II), Hg (II) is tetrahedral

which is proposed by the spectral study of the metal complexes. The Schiff bases and

metal complexes showed antifungal activity and VO (IV) and Hg (II) complexes

showed diuretic activity also. [333]

Figure 2.26

Chapter 2

Page 72

Figure 2.27

By the review of literature, it appears that Schiff bases and metals elements can be

play a vital role in enhancing the efficiency of a drug molecule and or decrease toxic

effects. Therefore, Schiff bases and the metals elements should be measured in drug

design studies.