Characterization, XPS and Toxicological Study of Organothallium (III) Compounds with Schiff Base Ligands

doi:10.4236/csta.2012.13018

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Crystal Structure Theory and Applications, 2012, 1, 97-99

http://dx.doi.org/10.4236/csta.2012.13018 Published Online December 2012 (http://www.SciRP.org/journal/csta)

Characterization, XPS and Toxicological Study of

Organothallium (III) Compounds with Schiff Base Ligands

Gyanendra Kumar Gaur1*, Shekhar Srivastava2

1Scientific Officer, Forensic Science Laboratory, Gwalior, India

2Reader in Chemistry, University of Allahabad, Allahabad, India

Email: *[email protected]

Received October 23, 2012; revised November 21, 2012; accepted November 29, 2012

ABSTRACT

Many Organothallium Compounds have been used in medicine, industry and antibacterial activity. Optical properties

are among the most fascinating and useful properties of many complexes and have been extensively studied using a

variety of optical spectroscopic techniques. A basic understanding of the optical properties and related spectroscopic

techniques is essential for characterization about semiconductors, insulators or metal. Optical properties are related to

other properties and functionalities (e.g. electronic, magnetic, and thermal) that are of fundamental importance to many

technological applications, such as energy conversion, chemical analysis, biomedicine, opto-electronics, communication,

and radiation detection. The fundamental importance of Thallium is the ability to accept electrons due to empty d-orbi-

tals and thus establish additional bonds (σ bond and π bond) in chemistry. The Thallium metal, which has outer elec-

tronic configuration 6 s2, 6 p1 shows oxidation states of Thallium (III) and Thallium (I). This research paper explains

that Thallium (III) and Thallium (I) accepts lone pairs from various bi-dentate tetra-dentate Schiff base ligands due to

p-orbital and vacant d-orbital. This research paper explains the Characterization, XPS and Toxicological Study of Or-

ganothallium (III) Compounds with Schiff base ligands by physiochemical technique. X-Ray photoelectron spectrogra-

phy (XPS) study of Thallium (III) complexes with Schiff Base ligands also reported in this paper. XPS study shows a

single symmetrical peak without any splitting in photoelectron peak, which confirms diamagnetic nature of all prepared

molecular adducts. All prepared complexes with Schiff base ligands show toxicological effect.

Keywords: Oxidation; Ligand; Diamagnetic; Organothallium Compound; Molecular Adducts

1. Introduction

The organometallic chemistry has developed rapidly in

III-B group of metals like gallium, indium and thallium

during few years. The organometallic compounds of these

metals have found useful applications in the production

of metal carbonyls [1], metal cyclo-pentadiencyls [2-4]

and ultra pure metals [5,6]. Some important applications

of organometallic compounds of the metals are used as

lubricants [7], antiknock reagents [8] and polymerization

catalysts for olefins [9-11]. Poisoned food technique and

Toxicological study has been recently employed to de-

termine the fungicidal activity of these compounds. Pre-

liminary evaluation of biocidal activity of some compounds

against tomato seedlings has indicated that organometa-

llic compounds of these metals are potential fungicides

[12].

2. Experimental Details

The physicochemical technique was used for synthesized

organothallium (III) in present work. The elemental

analysis was determined on a semimicro scale at Central

Drug Research Institute, Lucknow, India. Molar conduc-

tance of all complexes was measured at room tempera-

ture in Acetone by Digisun Electronics Conductivity

Bridge. The X-ray photoelectron spectra (XPS) were

recorded by VG Scientific ESCA-3MK II electron spec-

trometer at National Chemical Laboratory, Poona-6. The

MgKα X-ray line (1253.6 eV) was used for photo excita-

tion. The Cu2p3/2 (B.E. = 932.8 ± 0.2 eV) and Au4f7/2

(B.E. = 368.2 eV) was used for cross-checking. All the

spectra were recorded using the same spectrometer pa-

rameters of 50 eV pass energy and 4 mm slit width. The

reduced full width at half maximum (FWHM) at the

Au4f7/2 (B.E. = 83.8 eV) level under these conditions was

1.2 eV [13].

3. Chemical Analysis

The powdered sample was mixed with high purity silver

powder to reduce the charging effect. A thin layer of

such a sample was pressed on a gold metal gauge which

*Corresponding author.

G. K. GAUR, S. SRIVASTAVA

was welded to nickel sample holder. The Ag3d5/2 level

(BE = 368.2 eV) obtained which was sharp and did not

show any observable shift. Thus, the charging of the

sample was negligible. The spectra were recorded in trip-

licate in the region. In different cases the binding ener-

gies were reproducible within ±0.1 eV.

The physicochemical technique was used for prepara-

tion of hydrated Thallium (III) Chloride (TlCl3·4H2O).

Thallium Chloride (TlCl) was obtained from reacting

Thallium Methal with HCl in 1:1 molar ratio in the pre-

sence of HNO3 and H2SO4. Hydrated Thallium (III)

Chloride was obtained by passing a current of Chloride

through an aqueous suspension of Thallium (I) Chloride

till a clear solution was obtained. The solution was then

concentrated in a current of Chloride at 60˚ and cooled in

a freezing mixture and salt to yield colorless plates of

Tetra-hydrated Thallium (III) Chloride (TlCl3·4H2O).

Phenyl Thallium Chloride (PhTlCl2) has been prepared

by the reaction of Thallic Chloride with Phenylboric acid

in water. It has been recrystallised from water [14].

Phenylboric acid was obtained from phenyl magnesium

bromide and n-butylborate in ether [15]. Among the or-

ganmetallics of the III (B) group of elements, those of the

general formula RMX2 (where R = Ph, X = Cl) have re-

ceived considerable attention of the workers due to their

significantly high thermal stability.

RMX2 (where R = Phenyl, M = Tl, and X = Cl) have

sp2 hybridization with one vacant p-orbital and five

d-orbital. These vacant orbital can accept lone pair from

various donors and form molecular adducts of the type

RMX2D; RMX2L where (D = monodenate donor; L =

bidenate donor). Many PhTlCl2 complexes with bidenate

Schiff base ligands have been synthesized and charac-

terized by physicochemical technique. Table 1 shows the

analytical data of Phenyl Thallium Chloride (PhTlCl2

SB).

Table 1. Analytical data of Phenyl Thallium Chloride

(PhTlCl2·SB).

S.No. Complex % Found (calculated)

Molar

conductance in

acetone

(ohm–1cm2

mol–1)

Tl C H N

1. PhTlCl2SB13 31.6

(31.77)

44.4

(44.85)

3.4

(3.58)

8.3

(8.72) 25

2. PhTlCl2SB14 34.4

(34.45)

40.4

(40.54)

3.2

(3.34)

9.2

(9.45) 26

3. PhTlCl2SB15 33.2

(33.22)

42.6

(42.99)

3.1

(3.09)

9.0

(9.12) 28

4. PhTlCl2SB16 36.0

(36.17)

38.1

(38.29)

3.0

(3.01)

9.5

(9.92) 30

5. PhTlCl2SB17 31.4

(31.92)

45.0

(45.07)

3.0

(3.12)

8.6

(8.76) 22

4. Results and Discussion

The complex of Organothellium (III) with bidenate Schiff

base ligands and molecular adducts have been synthe-

sized and characterized by the interaction of PhTlCl2 in

Chloroform. It is clear from Table 1 that these com-

plexes were stable towards atmospheric oxygen, moisture

and at room temperature on long time. Molar conduc-

tance of 10–3 M solution of the complexes was deter-

mined at room temperature. Figure 1 shows the geomet-

rical structure of PhTlCl2 with schiff base ligands which

confirmed their stability. It is observed that the absence

of Ionic species in the range of 20 ohm–1 cm2 mol–1 to 30

ohm–1 cm2 mol–1 in acetone. All the molecular adducts

exhibit the C = N absorption around 1620 cm–1 to 1610 cm–1

which normally appears at 1640 cm–1 in the free ligands.

The lowering of this band in the complexes indicates the

coordination of nitrogen atoms of Azomethine group to

the Thallium (II) and Thallium (III). Figure 2 shows the

N1s photoelectron peak and binding energy (eV) of

PhTlCl2 with Schiff base ligands. It is observed that the

PhTlCl2·SB shows Tl4f, N1s and 01s photoelectron peak

from X-ray photoelectron spectra (XPS) study. XPS

study shows that the binding energy increases as well as

the electron density on Thallium metal ion by coordina-

tion of Schiff base ligands with Thallium metal ion.

Figure 1. The Geometrical structure of PhTlCl2 with Schiff

base ligands.

PhTlCl

389 395 401 407

N1s Photoelectron Peak

Figure 2. N1s photoelectron peak and binding energy (eV)

of PhTlCl2 with Schiff base ligands.

G. K. GAUR, S. SRIVASTAVA

5. Conclusion

It is clear that the photoelectron peaks towards higher

binding energy side due to L → M charge transfer from

XPS Study. All prepared complexes are stable under at-

mospheric conditions at room temperature and it is con-

firmed through their geometrical structure. XPS study

shows a single symmetrical peak without any splitting in

photoelectron peak, which confirms diamagnetic nature

of all prepared molecular adducts. Toxicological study of

these complexes found very prominent.

6. Acknowledgements

I am thankful to the Central Drug Research Institute,

Lucknow, India for elemental analysis of Thallium (III)

and National Chemical Laboratory, Poona-6 for X-ray

photoelectron spectra (XPS).

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