Studies on 1,10-phenanthroline complexes of some hydroxyaryltellurium trihalides

Article abstract of DOI:10.1080/10426500802059760

The synthesis and structural features of some newly synthesized 1,10-phenanthroline complexes of p-hydroxyphenyl-and 3-methyl-4- hydroxyphenyltellurium trihalides (chlorides, bromides, and iodides) are reported. The resulting complexes have been subjected to elemental analyses, conductance and cryoscopic measurements, infra-red and proton magnetic resonance spectral studies. Solution studies reveal the weak to 1:1 electrolyte type behavior of these complexes in solution. Spectral studies indicate the linkage of phenanthroline to the tellurium atom through the nitrogen atoms. Central tellurium atom in these complexes is hexa-coordinated in an octahedral way. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500802059760

This article was downloaded by: [Australian National University]
On: 01 January 2015, At: 08:45
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,
UK
Phosphorus, Sulfur, and Silicon
and the Related Elements
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/gpss20
Studies on 1,10-Phenanthroline
Complexes of Some
Hydroxyaryltellurium Trihalides
K. K. Verma a , Seema a & Shashi Chhabra a
a Department of Chemistry , M.D. University
Rohtak , Rohtak, India
Published online: 03 Nov 2008.
To cite this article: K. K. Verma , Seema & Shashi Chhabra (2008) Studies
on 1,10-Phenanthroline Complexes of Some Hydroxyaryltellurium Trihalides,
Phosphorus, Sulfur, and Silicon and the Related Elements, 183:12, 3037-3045, DOI:
10.1080/10426500802059760
To link to this article: http://dx.doi.org/10.1080/10426500802059760
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the
information (the “Content”) contained in the publications on our platform.
However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness,
or suitability for any purpose of the Content. Any opinions and views
expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the
Content should not be relied upon and should be independently verified with
primary sources of information. Taylor and Francis shall not be liable for any
losses, actions, claims, proceedings, demands, costs, expenses, damages,
and other liabilities whatsoever or howsoever caused arising directly or
indirectly in connection with, in relation to or arising out of the use of the
Content.

This article may be used for research, teaching, and private study purposes.
Any substantial or systematic reproduction, redistribution, reselling, loan,
sub-licensing, systematic supply, or distribution in any form to anyone is
expressly forbidden. Terms & Conditions of access and use can be found at
http://www.tandfonline.com/page/terms-and-conditions

Phosphorus, Sulfur, and Silicon, 183:3037–3045, 2008
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500802059760
Studies on 1,10-Phenanthroline Complexes of Some
Hydroxyaryltellurium Trihalides
K. K. Verma, Seema, and Shashi Chhabra
Department of Chemistry, M.D. University Rohtak, Rohtak, India
The synthesis and structural features of some newly synthesized
1,10-phenanthroline
complexes
of
p-hydroxyphenyl-
and
3-methyl-4-
hydroxyphenyltellurium trihalides (chlorides, bromides, and iodides) are
reported. The resulting complexes have been subjected to elemental analyses,
conductance and cryoscopic measurements, infra-red and proton magnetic
resonance spectral studies. Solution studies reveal the weak to 1:1 electrolyte type
behavior of these complexes in solution. Spectral studies indicate the linkage
of phenanthroline to the tellurium atom through the nitrogen atoms. Central
tellurium atom in these complexes is hexa-coordinated in an octahedral way.
Keywords p-Hydroxyphenyltellurium trihalides; 3-methyl-4-hydoxyphenyltellurium
trihalides; phenanthroline complexes
INTRODUCTION
Aryltellurium trihalides are known to behave as Lewis acids and form
molecular complexes with several nitrogen, oxygen, and sulfur donor
bases.1−14 Tellurium in these complexes is penta- or hexa-coordinated,
but the reports on hexa-coordinated complexes are few.4,9−13 A small
number of such compounds are known6,7 to posses antimicrobial activ-
ity, as well. The hydroxyaryltellurium trihalides have two active sites to
interact with the nitrogen donor bases: the acidic phenolic proton; and
the acceptor tellurium atom. Earlier, we reported10−13 the complexes of
various hydroxyaryltellurium trihalides with pyridine, 2,2ꢀ-bipyridyl,
piperidine, and thiourea. The present paper describes the synthesis
and characterization of 1,10-phenanthroline complexes of hydroxyaryl-
tellurium trihalides derived from phenol and o-cresol.
Received 2 September 2007; accepted 5 November 2007.
The authors are thankful to Maharshi Dayanand University, Rohtak (India) for nec-
essary facilities.
Address correspondence to K. K. Verma, Department of Chemistry, Maharshi
Dayanand University, Rohtak 124001, India. E-mail: vermakk123@rediffmail.com
3037

3038
K. K. Verma et al.
RESULTS AND DISCUSSION
The formation of p-hydroxyphenyltellurium trichloride and 3-methyl-
4-hydroxyphenyl-tellurium trichloride by reaction of tellurium tetra-
chloride with phenol15,16 and o-cresol15,17 involves the electrophilic
substitution of the aromatic ring, by a TeCl+3 group at a position para
to the hydroxyl group:
R H + TeCl4 → RTeCl3 + HCl.
(1)
Hydroxyaryltellurium trichlorides undergo halogen-exchange15−17
when treated with KBr or KI:
RTeCl3 + 3KX → RTeX3 + 3KCl(X Br, I).
(2)
Reactions of these hydroxyaryltellurium trihalides with 1,10- phenan-
throline in 1:1 molar ratio yield RTeX3. Phen type complexes:
RTeX3 + Phen → RTeX3 . Phen.
(3)
These complexes are colored crystalline solids, fairly stable in dry air,
and soluble in polar organic solvents.
Conductance and Cryoscopic Studies
The molar conductance data of ca.10−3 M solutions in nitroben-
zene, acetone and acetonitrile (Table I) reflect the weak to 1:1 elec-
trolytic behavior of these complexes in solution, presumably due to
ionization into [RTeX2.Phen]+ and X− ions. Complexes of 3-methyl-4-
hydroxyphenyltellurium trihalides appear to be more dissociated than
those of p-hydroxy phenyltellurium trihalides. Also, the complexes of
triiodides appear to be most dissociated and those of trichlorides least
dissociated. The lower values of molar conductance than those of 1:1
electrolytes,18 in some cases, may be due to incomplete dissociation or
ion-pair formation.
It has been noted18 that the concentration ranges selected for such
measurements are often arbitrarily chosen and that the method of de-
termination requires the assumption of the molecular weight, which
may be erroneous. The complexes that are predicted as 1:1 electrolytes
by ꢀM data and have sufficient solubility were, therefore, investigated
in acetonitrile over a wider range (1 – 5 mM), and the results sub-
jected to the Onsager Law. Values of equivalent conductance at infinite
dilution, ꢀo and (A + ω Bꢀo) are recorded in Table I. A comparison
of calculated and experimental values of (A + ω Bꢀo) shows17,19 the
compounds to behave as 1:1 electrolytes. A higher ratio than expected
reflects the incomplete dissociation or ion-pair formation. Molecular

3039

3040
K. K. Verma et al.
TABLE II Important IR Spectral Data (cm−1) of Phenanthroline
Complexes of Hydroxyaryltellurium Trihalides
R
Complex
υ
δ(OH)
υ
C
O
H
N
p-Hydroxyphenyl
RTeCl3.Phen
3400 mb
1380 w
1368 w
1385 w
1364 w
1390 w
1370 w
1395 w
1630 w
1614 m
1618 m
1628 m
1625 w
1616 m
1630 w
1613 m
1626 w
RTeBr3.Phen
RTeI3.Phen
RTeCl3.Phen
3429 sb
3401 mb
3306 mb
3-Methyl-4-hydroxyphenyl
RTeBr3.Phen
RTeI3.Phen
3435 mb
3430 mb
1393 w
w = weak; m = medium; s = strong; and b = broad.
weights in nitrobenzene (Table I) are much lower than the formula
weights, supporting the results of conductance studies.
Infra-Red Spectra
The IR spectra of phenanthroline adducts are quite complex and there-
fore, an attempt has been made to identify the donor sites of the ligand
by comparing the spectra of the complexes with those of parent hydrox-
yaryltellurium trihalide and phenanthroline.
All the complexes (Table II) show a broad band at about 3400 cm−1
(O H stretching) and at about 1360−1390 cm−1 (OH deformation),
which reflects the non participation of hydroxyl group of hydrox-
yaryltellurium trihalides toward bonding with phenanthroline. Several
researchers7−9,20−22 have discussed the IR spectra of phenanthroline
and its complexes and have exploited the spectral data for identifica-
tion of donor sites. In the spectra of phenanthroline complexes, strong
bands are expected20 in three frequency regions namely between 700
and 900 cm−1, between 1125 and 1250 cm−1, and between 1400 and
1650 cm−1. In the spectra of complexes of hydroxyaryltellurium tri-
halides, the satisfactory assignments of bands in earlier two regions are
not possible due to the presence of organyl moiety of RTeX3group. It is
the third region that characteristic ring frequencies of phenanthroline
occur. The intense bands at about 1500 cm−1, 1590 cm−1and 1423 cm−1
are reported 20 to move towards higher frequencies on coordination, the
1423 cm−1 band being least sensitive. This is the υC N band, which most
researchers have reported7−9,21,22 to shift towards higher frequency
upon complexation. The complexes of hydroxyaryltellurium trihalides

1,10-Phenanthroline Complexes of Some Hydroxyaryltellurium Trihalides 3041
show medium to strong intensity bands around 1610−1630 cm−1, which
were not present in the parent hydroxyaryltellurium trihalides. This
certainly suggests the linkage of 1,10-phenanthroline molecule to the
tellurium atom of RTeX3through the two nitrogen atoms, thus enhanc-
ing the coordination number of tellurium to six in these complexes.
Proton Magnetic Resonance Spectra
1H NMR spectral data for hydroxyaryltellurium trichlorides complexes
are presented in Table III.
1,10- Phenanthroline shows23 four sets of two equivalent protons
each at δ 7.62 (a), 7.80 (b), 8.26 (c), and 9.21(d) ppm. Upon complexation
with hydroxyaryltellurium trichlorides, these are shifted to downfield
side, whereas the aryl protons of hydroxyaryltellurium moiety shift to
upfield side. The OH proton of hydroxyaryl group remains intact in the
complexes showing its non participation as predicted by IR studies, as
well. Although a lot of mixing of signals of protons of phenanthroline
and hydroxyaryl groups takes place, yet independent assignments of
1
downfield protons (Hc and Hd) are possible. These results of H NMR
spectra suggest the linkage of phenanthroline to the tellurium atom
through nitrogen atoms.
On the basis of above spectral evidences, tellurium appears to be
hexacoordinated in these phenanthroline complexes, presumably in an
octahedral environment. However, in the absence of X-ray studies it is
very difficult to assign the exact geometry of the molecules and stereo-
chemical role of the lone pair on tellurium.
EXPERIMENTAL
All preparations were carried out under an atmosphere of dry nitrogen
24,25
and the solvents were dried and purified by standard methods
before use.
Preparation of Hydroxyaryltellurium Trihalides
The p-hydroxyphenyltellurium trichloride and 3-methyl-4-hydroxy-
phenyltellurium trichloride were prepared by reactions of tellurium
tetrachloride with phenol and o-cresol, respectively.15−17 The corre-
sponding tribromide and triiodide were prepared by halogen-exchange
process using potassium bromide or potassium iodide.15–17

3042
K. K. Verma et al.
TABLE III PMR Spectral Data of Phenanthroline Complexes of
Hydroxyaryltellurium Trichlorides in DMSO-d6
Complex
Chemical shift (δ ppm)
Assignment
6.84d (2H)
7.82−8.09cm (6H)
8.58d (2H)
HB
HA, Ha, and Hb
Hc
Hd
OH
9.20d (2H)
9.80b (1H)
p-HOC6H4TeCl3 . Phen
2.31s(3H)
CH3 proton
HB
HA, HC, Ha, Hb, and OH
6.84, 6.98b (1H)
7.70−8.21cm (7H)
RTeCl3.Phen
(R = 3-methyl-4-hydroxyphenyl)
8.58d (2H)
9.20d (2H)
Hc
Hd
b = broad; d = doublet; cm = complex multiplet; and s = singlet.
Synthesis of 1,10-Phenanthroline Complexes
A saturated solution of 1,10-phenanthroline monohydrate (0.99 g,
5.0 mmol) in about 20 mL dichloromethane was added to a saturated
solution of 5.0 mmol (1.64 g, 2.30 g, 3.01 g for p-hydroxyphenyltellurium
trichloride, tribromide, triiodide; 1.71 g, 2.37 g, 3.08 g for 3-methyl-4-
hydroxyphenyltellurium trichloride, tribromide, and triiodide, respec-
tively) of hydroxyaryltellurium trihalide in about 20 mL dry methanol/

3043

3044
K. K. Verma et al.
chloroform. The contents were refluxed for about 2 h. The solvent
was distilled off and the solid thus obtain was extracted with benzene
repeatedly and finally with chloroform and then dried over P4O10 in a
vacuum dessicator. The complexes were recrystallized from a mixture
of methanol and chloroform (50:50).
The purity of these compounds was checked by T.L.C. using silica
gel- G. The analytical data and physical properties of the complexes
are presented in Table IV.
Analytical Methods and Physical Measurements
Carbon, hydrogen, and nitrogen analyses were obtained micro-
analytically from sophisticated Analytical Instrumentation Facility,
Panjab University, Chandigarh. The tellurium content was estimated
volumetrically.26 Conductivity was measured at 25 2oC with a con-
ductivity bridge type 305 Systronics model and the molecular weights
were determined by the cryoscopic method in nitrobenzene up to the
saturation point. IR spectra were recorded in the region 4000−400 cm−1
at University of Delhi on a SHIMAZDU FTIR - 8300 Spectrometer, us-
ing the KBr pellets technique. 1H NMR spectra were recorded at SAIF,
Panjab University, Chandigarh on BRUKER AVANCE II 400 NMR
Spectrometer operating at 400.13 MHz in DMSO- d6using tetramethyl-
silane as an internal reference
REFERENCES
[1] K. J. Wynne and P. S. Pearson, Inorg. Chem., 10, 2735 (1971).
[2] K. J. Wynne and P. S. Pearson, J. Chem. Soc., Chem. Commun., 556 (1970).
[3] K. J. Wynne, A. J. Clark, and M. Berg, J. Chem. Sec. Dalton, 2370 (1972).
[4] E. R. Clark, A. J. Collet, and D. G. Naik, J. Chem. Soc. Dalton, 1961 (1973).
[5] M. C. Berg, Diss. Abstr. Int. B, 33 (7), 2982 (1972).
[6] T. N. Srivastava, M. Singh, and H. B. Singh, Indian J. Chem., 21 (A), 307 (1982).
[7] T. N. Srivastava, R. C. Srivastava, and M. Srivastava, Indian J. Chem., 21 (A), 539
(1982).
[8] T. N. Srivastava, R. C. Srivastava, and V. K. Srivastava, J. Indian Chem. Soc., 60,
891(1983).
[9] M. V. Garad, Polyhedron, 4, 1353(1985).
[10] K. K. Verma and Reena, Synth. React. Inorg. Met. -Org. Chem., 29, 499 (1999).
[11] K. K. Verma, R. Dahiya, and D. Soni, Synth. React. Inorg. Met. -Org. Chem., 29,
1033 (1999).
[12] K. K. Verma and R. Dahiya, Synth. React. Inorg. Met.-Org. Chem., 29, 1299 (1999).
[13] K. K. Verma and Reena, Phosphorus, Sulfur, and Silicon and the Related Elements,
148, 227 (1999).
[14] Reena, Ph.D. Thesis, M. D. University Rohtak, Rohtak, India (1999).
[15] K. Kumar, Ph.D. Thesis, IIT Delhi, New Delhi, India (1981).

1,10-Phenanthroline Complexes of Some Hydroxyaryltellurium Trihalides 3045
[16] B. L. Khandelwal, K. Kumar, and F. J. Berry, Inorg. Chim. Acta, 47, 135 (1981).
[17] B. L. Khandelwal, K. Kumar, and K. Raina, Synth. React. Inorg. Met. –Org. Chem.,
11, 65 (1981).
[18] W. J. Geary, Coord. Chem. Revs., 7, 81 (1971).
[19] K. K. Verma, S. Chand, and S. Garg, Synth. React. Inorg. Met. –Org. Chem., 24, 979,
(1994).
[20] A. A. Schilt and R. C. Taylor, J. Inorg. Nucl. Chem., 9, 211 (1959).
[21] B. Sey Ferth and N. Kahlen, J. Organometal. Chem., 25, 809 (1960).
[22] A. A. Osowole, J. A. O. Woods, and O. A. Odunola, Synth. React. Inorg. Met. –Org.
Chem., 32, 783 (2002).
[23] Shin-ichi, Hand Book of Proton NMR Spectra and Data, Asani Research Centre,
Ed. (Academic Press, Amsterdam, 1985).
[24] A. I. Vogel, A Text Book of Practical Organic Chemistry (Longman, London, 1991),
5th ed., pp. 131–234.
[25] A. Weissberger, Ed., Techniques of Organic Chemistry (Interscience Publishers, Inc.,
New York, 1967), Vol. VII, 2nd ed.
[26] A. I. Vogel, A Text Book of Quantitative Inorganic Analysis Including Elementary
Instrumental Analysis (Longman, London, 1975) 3rd ed., p. 324.