Thermal studies and vibrational analyses of m-methylaniline complexes of Zn(II), Cd(II) and Hg(II) bromides

Article abstract of DOI:10.1016/S1386-1425(02)00415-8

The complexes having the MBr₂L₂ (M: Zn, Cd and Hg; L: m-methylaniline) formulae have been prepared and characterized by their elemental analyses, thermogravimetric analyses, IR and Raman spectral studies. IR and Raman bands of the complexes have been assigned as compared with the free ligand. Coordination effects on the internal modes of m-methylaniline have been discussed. Vibrational spectra propose that the [ZnBr₂(mMA)₂] complex is in a tetrahedral environment around Zn(II) ion with C_2v symmetry whereas Cd(II) and Hg(II) complexes have 5-coordinate polymeric bromide bridged structures.

Full text of DOI:10.1016/S1386-1425(02)00415-8

Spectrochimica Acta Part A 59 (2003) 1841Á1847
/
www.elsevier.com/locate/saa
Thermal studies and vibrational analyses of m-methylaniline
complexes of Zn(II), Cd(II) and Hg(II) bromides
K. Golcuk *, A. Altun, M. Kumru
Department of Physics, Fatih University, 34900 B. Cekmece, Istanbul, Turkey
Received 4 September 2002; received in revised form 13 November 2002; accepted 13 November 2002
Abstract
2 2
The complexes having the MBr L (M: Zn, Cd and Hg; L: m-methylaniline) formulae have been prepared and
characterized by their elemental analyses, thermogravimetric analyses, IR and Raman spectral studies. IR and Raman
bands of the complexes have been assigned as compared with the free ligand. Coordination effects on the internal
2 2
modes of m-methylaniline have been discussed. Vibrational spectra propose that the [ZnBr (mMA) ] complex is in a
tetrahedral environment around Zn(II) ion with C2v symmetry whereas Cd(II) and Hg(II) complexes have 5-coordinate
polymeric bromide bridged structures.
#
2002 Elsevier Science B.V. All rights reserved.
Keywords: ZnBr , CdBr and HgBr complexes; m-methylaniline; Thermal analysis; IR and Raman spectra
2
2
2
1
. Introduction
Aniline and its derivatives are of great industrial
In this paper, we report thermogravimetric (TG)
behaviors and vibrational analyses of metal(II)
[Zn(II), Cd(II) or Hg(II)] bromide complexes with
m-methylaniline (also known as 3-C H N, m-
importance. Hence, understanding of their mole-
cular properties and the reactions they experience
is very important. For that purpose, a number of
first row transition metal dihalide complexes of
aniline and its derivatives have been synthesized
7
9
toluidine and abbreviated as mMA). Particularly,
in plane and out of plane deformation bands of
NH group in the spectra of complexes have been
2
carefully revised. MetalÁligand vibrational modes
/
and investigated so far [1Á7]. However, there have
/
have been used to characterize each metal complex
and to interpret the type of coordination around
each metal.
been no complete vibrational and thermal studies
for most of these complexes. There are also some
disagreements for the assignments of amino group
To the best of our knowledge, only the IR study
vibrations [2Á8].
/
of the ligand and metalÁligand vibrations of the
/
Zn(II) complex was previously reported [2]. We
present a more complete assignments of all ob-
served bands in IR and Raman spectra of the
previously studied Zn(II) complex. In addition to
*
Corresponding author. Tel.: ꢀ
12-889-1142.
E-mail address: kgolcuk@fatih.edu.tr (K. Golcuk).
/
90-212-889-0810; fax: ꢀ90-
/
2
1
386-1425/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
doi:10.1016/S1386-1425(02)00415-8

1842
K. Golcuk et al. / Spectrochimica Acta Part A 59 (2003) 1841Á1847
/
the Zn(II) complex, vibrational bands of the
Cd(II) and Hg(II) complexes were fully assigned.
No Raman measurements have been reported for
any of the metal(II) bromide mMA complexes so
far.
3. Results and discussion
3.1. Thermal analyses
Thermal decomposition data of the metal com-
plexes are listed in Table 2. As an example, TG
and DTG traces of Cd(II) complex are shown in
Fig. 1. All the complexes decompose in a two-stage
process.
2
. Experimental
The first stage corresponds to the loss of the 2
mol of mMA. The second decomposition stage
consists of the loss of the 1 mol of MBr , leaving a
very low percentage of a residue. The observed
weight losses for the decomposition processes in
each of the compounds compare favorably with
the theoretical values listed in Table 2. Thermal
stability of the complexes has an order of as
The ligand (L: mMA) and MBr (M: Zn, Cd
2
and Hg) were used as received from Aldrich Co.
As a continuation of the previous studies [1Á7], we
2
/
have just worked on the 1:2 MBr /L reactions. The
2
complexes were prepared by adding a solution of
mMA (2 mmol) in ethanolic solution to a solution
of MBr (1 mmol) in an equal volume of the same
2
solvent. After stirring for an hour, the polycrystal-
line complexes, which are all white in colour, were
filtered, washed with diethyl ether and dried under
pressure. Composition and purity were determined
in microanalytical laboratory with C, H, N, and
metal analyses (Table 1).
follows: Znꢀ
decreases while the mass of the metal atom
increases.
/
CdꢀHg. As it is seen, the stability
/
3.2. Vibrational study
The mid-IR spectra were recorded using KBr
ꢁ
All the typical bands of free ligand (mMA)
appear in the IR and Raman spectra of the metal
complexes. The FT-IR and FT-Raman spectra of
mMA and its complexes are shown in Figs. 2 and
3, respectively. All observed vibrational bands and
their assignments are given in Table 3. Vibrational
mode assignments of the free mMA are based on
ab initio and DFT calculations and fully reported
in Ref. [9]. A band for band correspondence is also
considered in the spectra of the compounds.
1
discs over range 4000Á
/
400 cm
on a Perkin
Elmer Paragon 1000 FT-IR. The far-IR spectra
were recorded using polyethylene discs over the
ꢁ
1
range 500Á
FT-IR spectrometer.
Raman spectra were recorded on a Bruker RFS
00/S FT-Raman Spectrometer in the range 3600Á
/200 cm
on a Mattson 2030 Galaxy
1
7
/
ꢁ
1
0 cm . It uses a 1.5 W Nd-YaG air-cooled laser
delivering excitation wavelength of 1064 nm.
TG and derivative TG (DTG) analyses were
made on a Mettler Toledo TG50 thermobalance
The NH group of free mMA gives rise to IR
2
ꢁ
1
absorption at 3435 cm (asymmetric stretch) and
3
ꢁ1
ꢁ1
under a flow of N (flow rate, 30 cm min ). The
2
at 3354 cm (symmetric stretch). These bands are
shifted towards lower wavenumbers on complex
sample was heated in an Al O crucible at a rate of
2
3
ꢁ
1
ꢁ1
1
0 8C min
.
formation up to 130 and 110 cm , respectively.
Table 1
Elemental analyses results for the metal complexes
Compound
Found (calculated) %
M
C
N
H
[
[
[
ZnBr
CdBr
HgBr
2
(mMA)
(mMA)
2 n
(mMA) ]
2
]
15.04 (14.88)
22.99 (23.01)
34.93 (34.90)
38.40 (38.26)
34.59 (34.56)
29.29 (29.26)
6.29 (6.37)
5.75 (5.76)
4.89 (4.87)
4.15 (4.18)
3.76 (3.73)
3.15 (3.16)
2
2 n
]
2

K. Golcuk et al. / Spectrochimica Acta Part A 59 (2003) 1841Á
/
1847
1843
Table 2
Thermal decomposition processes of the metal complexes
Compound
Process
Temperature range (8C)
DTG peak temperature (8C)
Weight loss (%)
Calculated Found
[
[
[
ZnBr
CdBr
HgBr
2
(mMA)
(mMA)
(mMA)
2
]
[ZnBr
[CdBr
[HgBr
2
(MmA)
(mMA)
(mMA)
2
]0
]0
]0
/
ZnBr
CdBr
HgBr
2
110Á
/
310
230
170
150
46.56
43.29
37.26
48.84
44.10
37.33
2
2
]
n
2
2
/
2
80Á/200
2
2
]
n
2
2
/
2
55Á/162
This shift suggests that coordination occurs via
lone pair electrons of nitrogen atom [1Á7] and can
be explained as a weakening of the NꢀH bonds
due to the electron drainage from nitrogen orbitals
to the metal atom with coordination [7,8]. It is
reported that there is a relationship between NH2
asymmetric and symmetric stretching vibration
bands, namely, n¯ sym ꢂ345:5ꢀ0:876 n¯ asym [10].
This relationship is almost valid in the spectra of
the complexes.
2ꢃ
/
1621 for 2,3-dimethylaniline and aniline mole-
cules, respectively. Hence, we assign the band at
/
ꢁ
1
3218 cm (3212 cm in Raman) as an overtone
1
of the 1622 cm . NH deformation intensified by
ꢁ1
/
ꢁ
2
Fermi resonance due to its proximity to the in-
phase stretching fundamental. The corresponding
band in the IR spectra of the complexes occurs
ꢁ
1
around 3115 cm
In the 2000Á1700 cm
meta-disubstituted benzene give rise to very weak
vibrations attributed to combination bands of Cꢀ
H out of plane bending vibrations [10]. The
.
ꢁ
1
/
region of IR spectra,
Shukla et al. [11] and Evans [12] assigned the IR
bands at 3230 and 3212 cmꢁ as an overtone of
/
1
ꢁ
1
2 2 n 2
Fig. 1. TG-DTG curves of [CdBr (mMA) ] (sample mass 9.0006 mg, heating ratio: 10 8C min , under N with a flow rate: 5
ꢁ
1
ml min ).

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K. Golcuk et al. / Spectrochimica Acta Part A 59 (2003) 1841Á1847
/
1570 cmꢁ region was
observed. Only the component of the lowest
1
triplet band in the 1620Á
/
1
frequency was said to be N-sensitive for some
5
related complexes [2,3]. Therefore, we can con-
clude that the NH scissoring vibration at 1622
2
ꢁ
1
cm in the spectra of mMA is lowered to
approximately 50 cm
The strong band observed at 1293 cm in both
ꢁ
1
by coordination.
ꢁ
1
IR and Raman spectra of mMA has been assigned
to nCꢀ
/
N stretching mode. Vibrations attributed to
this mode occur at lower frequencies in the spectra
of complexes.
Jungbauer and Curran [14] have performed a
comprehensive study of some metal halide com-
plexes and suggested that the NH wagging vibra-
2
Fig. 2. FT-IR spectra of (a) mMA, (b) [ZnBr
2 2
(mMA) ], (c)
tion is observed as a very strong and coordination
ꢁ
[
CdBr (mMA) and (d) [HgBr (mMA)
2
2
]
n
2
2 n
] .
1
sensitive band in the region 1185Á
/
1000 cm
,
ꢁ
1
while it appears at 670 cm in the IR spectrum of
aniline. Akalin and Akyuz [7] recently presented a
complete assignment of the bands of aniline and
transition metal(II) aniline complexes based on
normal coordinate analysis and ÁND2 experi-
/
ments. NH wagging vibration in metal complex
was found to shift upward in comparison to the
corresponding value in aniline. They have asserted
2
ꢁ
1
that this upward shift of 515Á
/330 cm
on
complex formation, which seems quite large,
results from the changes in hybridization about
the nitrogen atom. On the other hand, Engelter et
al. [2] assigned the NH wagging mode in mMA at
2
ꢁ
1
24 cm . But, we can say that this band is too
7
1
5
broad for determination of N-induced shift (Fig.
(a)). At the same time, they found that this mode
2
Fig. 3. FT-Raman spectra of (a) mMA, (b) [ZnBr
CdBr (mMA) and (d) [HgBr (mMA)
2
(mMA)
2
], (c)
was almost not affected on complex formation
although it was inclined to shift upward in aniline
complexes similar to the methylamine [15], aniline
[6,14], p-phenylendiamine [16] and benzidine [17]
complexes.
[
2
2
]
n
2
2 n
] .
pattern of these summation bands gives an indica-
tion of the type of substitution on the benzene ring
[
13].
Engelter et al. [2,3] reported that the IR spectra
of aniline, o-toluidine, m-toluidine and p-toluidine
Tzeng and Narayanan [18] have reported that
the amino group vibrations in pMA (p-methylani-
ꢁ
1
line) are found at 212 cm for the twisting mode,
ꢁ
1
ꢁ1
ꢁ1
in the 1625Á
/1590 cm
region showed two bands
of which only the higher frequency component was
at 641 cm for the wagging mode, at 1068 cm
ꢁ
1
for the rocking mode, at 1634 cm
for the
1
5
N-sensitive and therefore assigned to the NH2
scissoring vibration. The lower component was
scissoring mode, according to the results of ab
initio calculations and resonant two-photon ioni-
zation spectroscopy. An analogous order is also
presented for amino group vibrations of mMA
(Table 3) [9]. In this point of view, Engelter et al.
1
5
not affected by N-labelling and was indubitably
the nCꢀC ring band expected to occur in this
region. As to the IR spectra of the title complexes,
/

K. Golcuk et al. / Spectrochimica Acta Part A 59 (2003) 1841Á
/
1847
1845
Table 3
Infrared and Raman frequencies of mMA and metal complexes
mMA
IR
[ZnBr
2
(mMA)
2
]
[CdBr
2
(mMA)
2
]
n
[HgBr (mMA)
2
2
]
n
Assignment
Ra
IR
Ra
IR
Ra
IR
Ra
3
3
3
3
3
2
2
2
2
1
435 s
354 s
218 m
034 m
3265 s
3353 m, br 3218 s
3212 m, br 3118 m
3271 m
3219 m
3119 w
3305 s
3248
3125
3306 m
3246
3292 s
3222 s
3110 w
3028 w
3291 w
3234 m
nNH (asym.)
nNH (sym.)
2ꢃ1620 over
/
3046 s
3032 w, sh 3048 s
3012 w, sh 3017 w, sh 3030 m
3050 w
3051 s
3019 m, sh
2980 w, sh
3053 s
3013 w
2977 w
2947 w
2914 s
2857 w
nCH ring
nCH ring
nCH ring
nCH ring
015 m, sh 3012 s
975 m, sh 2974 m
946 m, sh
2978 w
2949 w
2916 m
2980 w
2951 w, sh 2945 vw
2973 vw
919 m
857 w
622 vs
2919 s
2920 s
2859 m
1575 w
1617 s
1599 s
2918 m
2854 w
1572 s
1616 s
1598 s
1508 vw
1492 vs
1471 s
2919 s
2917 w
2851 w
1568 s
1613 s
nCH
nCH
3
(asym.)
(sym.)
2857 m, sh 2851 w
1620 s
2859 w
1568 vw
1617 m
1598 m
3
1574 s
615 s
2
1566 vw, br NH (sciss.)
1
1597 s
1612 m, sh
nCC ring
nCC ring
nCC ring
nCC ring
1
1
1
1
1
1
1
1
591 vs
1590 m
513 m, sh 1514 vw
1598 m, sh 1597 s
1509 vw
1494 vs
1470 s
1509 vw
1492 vs
1478 vw, sh 1472 s
1515 vw
1497 vw
1473 vw
1438 w, br
1375 m
493 vs
469 s
1493 vw
1495 w
1472 vw
1497 w
bCH
bCH
bCH
bCH
nCN
3
3
3
(asym.)
(asym.)
(sym.)
443 m, sh 1447 w, br 1442 m, sh 1436 w, br 1440 m, sh 1436 w, br
1437 m
1378 m
381 w
314 m
293 s
1378 m 1376 w
1313 m, sh 1306 vw
1378 s
1312 m
1275 w
1258 s
1170 s
1144 m
1038 vw
1001 vs
919 m
886 w
868 w
778 w
732 s
1376 w
1316 wv
1276 w
1262 s
1381 m
1313 w
1279 m, sh
1263 s
1313 w
1293 s
1276 w
256 m
1256 w
1238 m
1168 m
1277 w, sh
1253 s
1171 m
1
1
1
1
9
9
8
8
7
7
6
6
5
5
170 s
077 w
038 w
96 m
26 w
70 m
55 m
75 vs
26
1166 m
1075 w
1170 m
1146 m
1040
1170 m
1088 m
1172 m
1090 m
nCCH
bNH
gCCH
3
2
(rock.)
3
996 m
928 w
996 m
916 s
890 s
998 m, sh
920 s
888 s
1001 vs
921 w
888 vw
868 vw
776 m
734 s
996 m, sh
916 s
890
1000 vs
918 m
897 w
870 vw
779 w
734 m
690 m
1058 s
bCCC ring
bCCC ring
gCH ring; gCCC
gCH ring; gCCC
gCH ring; gCCC
Breathing
868 s
866 m
778 vs
732 m
688 vs
1050 vs
570 m
548 m
868
784 w
738 s
780 vs
728 m
688 vs
1100 vs
570 m
544 m
520 vw
443 m
778 vs
730 m
688 vs
1040 vs
574 w
542 w
91 vs
a
55
689 vw
1105 m
572 m
542 m
519 s
687 vw
1047 s
570 m
546 m
523 s
gCCC ring
2
gNH (wagg.)
57 m
38 m
gCCC ring
bCCC ring
bCCC ring
gCCC ring
543 m
5
18 m
31 w
4
445 w
419 w
384 m
296 m
662 vw
444 m
418 m
442 m
414 w
444 w
414 w
4
16 m
86 m
n(Mꢀ
/
N)
3
293 s
660 m
350 m
283 m
591 vw, br
376 w, br
288 w
636 m
361 s
287 m
635 w, br
n(Mꢀ
/
N)
2
94 m
34 m
285 s
588 m
bCNH
2 3
; bCH
2
gNH (twist.)
2
646 m
226 m
205 m
227 m
197 vs
214 m
217 m
247 s
241 m
n(Mꢀ
/
Br)
t
183 vs
154 m
186 vs
n(Mꢀ/Br)
b
Key: n, stretching; b, in-plane deformation; g, out-of-plane deformation; s, strong; vs, very strong; m, medium; w, weak; vw, very
weak; sh, shoulder; br, broad.
a
Mode has not been observed, but has been found based on ab initio and DFT calculations [9].
[
near 1100 cm as the NH twisting mode instead
2] erroneously assigned the very strong IR bands
ꢁ
of NH2 wagging mode in the spectra of some
transition metal(II) complexes with mMA. The
1
2

1846
K. Golcuk et al. / Spectrochimica Acta Part A 59 (2003) 1841Á1847
/
ꢁ
1
above discussion suggest that the 1100 cm
(IR)
(IR) (1047 (Ra)
cm 1) and 1040 cmꢁ1 (IR) (1058 (Ra) cmꢁ1
ꢁ
1
ꢁ1
(
1105 (Ra) cm ), 1050 cm
ꢁ
)
bands of the Zn(II), Cd(II) and Hg(II) complexes,
respectively, are to be NH wagging mode. The
2
NH2 wagging mode is halogen sensitive. For
example, the values of this mode in Zn(II) bromide
and Zn(II) iodide mMA complexes [19] follow the
order of IB/Br.
The NH twisting mode has been observed at
ꢁ
2
1
2
34 cm
(Ra) in the spectrum of mMA. This
ꢁ
1
350 cm in the
mode has an upward shift of 430Á
/
spectra of the complexes, which is related to the
second ionization potentials of the metals as stated
in aniline complexes [6,7].
A very intense band is found near 1000 cmꢁ in
both Raman spectra of mMA and its complexes,
indicating the meta-disubstituted ring. This band
is due to a symmetrical in plane ring deformation
1
200 cmꢁ1 region) spectra of (a)
2
(mMA) and (c) [HgBr -
Fig. 4. Far-IR (500Á
ZnBr (mMA) ], (b) [CdBr
(mMA) ] .
/
[
2
2
2
2
]
n
2
n
ꢁ
1
Br) bands occur below 230 cm . Thus, the low
[
9,13,18], although it is known as a ring breathing
t
mode [6]. This band appears as a weak feature in
the IR spectra of mMA and Zn(II) complex, while
it appears as a weak shoulder in the IR spectra of
Cd(II) and Hg(II) complexes. We assign the strong
frequency spectra are consistent with previously
reported Zn(II) complexes [2,3,20,21,23].
ꢁ
1
The 214 cm far-IR band of Cd(II) complex is
due to the stretching vibration of the terminal Cdꢀ
Br) . The stretching vibrations
/
ꢁ
1
Raman but weak IR bands near 730 cm
to the
Br bond, i.e. n(Cdꢀ
of the bridging Cdꢀ
should appear below 200 cm
/
t
ring-breathing mode according to ab initio and
DFT studies [9,18].
In the low frequency region, especially below
/
Brꢀ
/
Cd bonds, i.e. n(Cdꢀ
/
Br)b,
ꢁ1
[23]. In Raman
ꢁ1
spectrum (Fig. 3(c)), while the 217 cm
assigned to n(Cdꢀ
bands are assigned to n(Cdꢀ
band is
ꢁ1
ꢁ
1
5
00 cm , it is considered that the metalÁ
vibrations occur [20]. Assignments of the n(Mꢀ
Br) vibrations, listed in Table 3, have
/
ligand
/
Br) , the 183 and 154 cm
t
/N)
/
Br) . Similarly, the
b
and n(Mꢀ
/
ꢁ1
247 cm
band in the far-IR spectrum of Hg(II)
been given carefully by considering the internal
modes of mMA and comparing with literature
complex is most probably due to n(Hgꢀ
/
Br) , while
t
ꢁ
1
the n(Hgꢀ
/
Br) appear below 200 cm
[24]. As
seen in Raman spectrum of mercury complex (Fig.
ꢁ
1
b
reports [1Á
tra of the complexes are shown in Fig. 4.
In [ZnBr (mMA) ], the metal ion is involved in a
/
7,21]. The 500Á
/
200 cm
region spec-
3
observed at 186 cm
(d)), the bridging Hgꢀ
.
In some previous works, [MCl (aniline) ] [6,25]
/
Brꢀ
/
Hg bond stretching is
2
2
ꢁ1
tetrahedral N ZnBr skeleton. Assuming C sym-
2v
2
2
2
2
metry for this complex, both the antisymmetric
and symmetric ZnBr and ZnN stretching vibra-
and [MX (pyridine) ] (M: Cd, Hg; X: Cl, or Br)
2
2
2
2
[
21] complexes were designated as distorted octa-
tions are IR and Raman-active [2,21Á
metalÁligand stretching vibrations can be de-
scribed with A ꢀB and A ꢀB representations
/
23]. The
hedral structure consisting of halogen-bridged
polymers. The IR and Raman spectra of Cd(II)
/
/
/
1
1
1
2
and Hg(II) complexes show one terminal Mꢀ
/Br
for n(Znꢀ
The bands at 417 (IR) cm and 387 (IR) cm
N) stretching vibra-
/
Br) and for n(Znꢀ
/
N), respectively.
t
ꢁ
1
ꢁ1
stretching and two bands in the bridging stretch
region. Thus, the spectra of the complexes seem
incompatible with the proposed structures of ani-
line and pyridine complexes, but they can be
explained on the basis of 5-coordinate dinuclear
have been ascribed as n(Znꢀ
/
tions. These bands are also observed as weak
features in the Raman spectrum of Zn(II) com-
plex. The terminal Znꢀ
/
Br bond stretching n(Znꢀ
/

K. Golcuk et al. / Spectrochimica Acta Part A 59 (2003) 1841Á
/
1847
1847
[
3] C. Engelter, D. Thornton, J. Mol. Struct. 33 (1976) 119Á
26.
4] J.A. Lee-Thorp, J.E. Ruede, D.A. Thornton, J. Mol.
Struct. 50 (1978) 65Á71.
/
or 5-coordinate polymeric bromide bridged struc-
tures [23,24], while the Cd(II) and Hg(II) com-
1
[
plexes still contain terminal Mꢀ
/
Br bonds. The
/
poor solubility of the [CdBr (mMA) ] and
2 n
2
[5] M. Kumru, A. Aypar, Spectrochimica. Acta Part A 47
[
HgBr (mMA) ] complexes; n shows the poly-
2 2 n
(1991) 1789.
[
[
[
6] S. Akyuz, J.E.D. Davies, J. Mol. Struct. 95 (1982) 157Á
68.
7] E. Akalin, S. Akyuz, J. Mol. Struct. 482Á
81.
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7Á33.
/
meric character of the Cd(II) and Hg(II) com-
pounds, in both polar and non-polar solvents
suggests that they have polymeric structure [1].
The positions of the Raman active components
1
/
483 (1999) 175Á
/
1
of n(Mꢀ/N) mode vary with the second ionization
2
/
potentials of the metal whereas the upper IR
components are almost unaffected by metal sub-
stitution. The very strong Raman bands below 100
[9] A. Altun, K. Golcuk, M. Kumru, J. Mol. Struct.
(Theochem), in press.
[
[
10] N.B. Colthup, L.H. Daly, S.E. Wiberley, Introduction to
IR and Raman Spectroscopy, Third ed., Academic Press,
NY, 1990.
ꢁ
1
cm
are ascribed as the lattice mode of the solid
complexes [26] and couple with torsional mode of
CH3.
11] A.R. Shukla, C.M. Pathak, N.G. Dongre, B.P. Asthana, J.
Raman Spect. 17 (1986) 299.
In conclusion, the amino group vibrations are
affected by coordination, as discussed above. The
IR and Raman spectra, especially in the region
below 500 cm , of the complexes reveal the type
of coordination around each metal atom.
[12] J.C. Evans, Spectrochim. Acta 16 (1960) 428.
[13] J.B. Lambert, H.F. Shurvell, D.A. Lightner, R.G. Cooks,
Organic Structural Spectroscopy, Prentice Hall, New
Jersey, 1998.
ꢁ
1
[14] M.A.J. Jungbauer, C. Curran, Spectrochim. Acta 21
(
1965) 641.
[ZnBr (mMA) ] complex appears in a tetrahedral
2 2
environment around Zn(II) ion with C2v symmetry
[15] G.W. Watt, B.B. Hutchinson, D.S. Klett, J. Am. Chem.
Soc. 89 (1967) 2007.
[
[
[
[
[
[
16] A.E. Ozel, S. Akyuz, J.E.D. Davies, J. Mol. Struct. 348
1995) 77.
17] S. Akyuz, T. Bulut, A.E. Ozel, G. Basar, Vibrational
Spect. 14 (1997) 151Á154.
18] W.B. Tzeng, K. Narayanan, J. Mol. Struct. 446 (1998) 93Á
02.
whereas [CdBr (mMA) ] and [HgBr (mMA) ]
2 n
2
2 n
2
(
complexes have 5-coordinate polymeric bromide
bridged structures.
/
/
1
19] A. Altun, K. Golcuk, M. Kumru, Vibrational Spect., in
press.
20] L.F. Yang, Z. Peng, X. Ren, G. Cheng, P. Cai, Spectro-
Acknowledgements
We thank Dr Wolfgang H. Meyer for providing
research facilities in Max-Planck Institute for
Polymer Research, Germany, and Dr Mehmet
Somer for Raman measurements in Koc Univer-
sity, Turkey.
chim. Acta Part A 57 (2001) 2745Á
21] R.J.H. Clark, C.S. Williams, Inorg. Chem. 4 (1965) 350Á
357.
/2764.
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[22] R.L. Carter, Molecular Symmetry and Group Theory,
Wiley, New York, 1998.
[23] S.P. Perlepes, S. Kasselouri, A. Garoufis, F. Lutz, R. Bau,
Polyhedron 14 (11) (1995) 1461Á1470.
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[24] S. Kasselouri, A. Garoufis, S. Paschalidou, S.P. Perlepes,
I.S. Butler, N. Hadjiliadias, Inorg. Chim. Acta 227 (1994)
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