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Infrared spectroscopic studies on the Hofmann-Td-type complexes: Mn(pyridine)2Cd(CN)4 and Mn(pyridine)2Hg(CN)4
Journal of
MOLECULAR STRUCTURE
ELSEVIER
Journal of Molecular Structure 323 (1994) 53-58
Infrared spectroscopic studies on the Hofmann- T’&ype complexes: Mn(pyridine)~~d(C~)~ and Mn(pyridine)~Hg(C~~ Z. Kantarcia9*, N. Karacana, B. Davarcio@ub aGazi lhiversitesi, Fen Edebiyat Faktihesi, Teknikokdar, 06500 Ankara, Turkey bGazi ~~~vers~~esi, Fen Bilimieri EnstittW Teknikokullar, Ankara, Turkey
(First received 29 November 1993; in final form 4 February 1994)
Abstract Two new Hofmann-Td-type complexes, Mn(pyridine)$d(CN)4 and Mn(pyridine)zHg(CN)4, have been prepared and their infrared spectra are reported.
1. Introduction
Among Hofmann-type and analogous host frameworks, a group of complexes with the general formula CdL2M(CN)4, where L2 is a bidentate or a pair of monodentate ligand molecules containing N-donor atoms and M is Cd or Hg, is of special interest, since their structures act as excellent reservoirs for the thermally unstable chemical species such as cyclohexadienyl (C6H6) radicals [I]. In these compounds the host framework is formed from infinite -Cd-L2-Cd-L2chains extending along the a and b axes alternately and the tetrahedral M(CN), ions are arranged between the consecutive crossing -Cd-L&dLz- chains with the N-ends bound to the Cd atoms [2-81. This structure provides two kinds of cavities, a and p, for the guest molecules. The Q cavity has approximateiy the shape of a rectangular prism similar to those in Hofmann-type hosts, while the ,B cavity has the shape of a biprism, as *Correspondingauthor.
has been demonstrated in previous papers 12-41. The compounds possessing this type of host framework reported to date have only been confined to the Cd metal atom in an octahedral environment. Recently, Kasap [9] and Kasap and Kantarci [lo] prepared two novel Td-type benzene clathrates, Mn(NHs)2M(CN)4 - 2C6H6 (M = Cd or Hg). We have now prepared two new dipyridinemanganese (II) tetracyanometalate(I1) host complexes, Mn(pyridine)~M(CN)~ (M = Cd or Hg). In this study, the infrared spectroscopic results for Mn(II)(pyridine)zCd(II)(CN)4 (abbreviated to Mn-Cd-py) and Mn(II)(pyridine)zHg(II)(CN)4 (abbreviated to Mn-Hg-py~ are reported. For the purposes of comparison and discussion concerning the structure of these compounds, the infrared spectral data of the complex ~d(pyridine)~Cd(~N)~ (abbreviated to Cd-Cdpy) [I I] are quoted, since a single crystal X-ray structural study [12] has shown that this complex possesses a Hofmann-T&ype host framework.
0022-2860/94/$07.00 0 1994 Elsevier Science B.V. All rights reserved SSDZ 0022-2860(94)07985-J
54
Z. Kantarci et aLLI. Mol. Struct. 323 (f994j 53-58
2. Ex~~mental All chemicals used were reagent grade (Merck) and used without further purification. The complexes were prepared by adding slightly more than 2 mmoles of pyridine and 1 mmole of potassium tetracyanometalate solution in water to 1 mmole of Mn(I1) chloride solution in water. The brown precipitate was filtered, washed with water, ethanol and ether successively, and stored in a desiccator. The freshly prepared samples were analyzed for Mn and Cd with a Philips P49200 atomic absorption spectrophotometer, and for C, H and N with a Leco CHN-600 analyzer with the results as follows. Calculated for Mn-Cd-py: Mn, 12.79; Cd, 26.17; C, 39.14; H, 2.35; N, 19.56. Found: Mn, 12.89; Cd, 26.28; C, 38.60; H, 2.42; N, 19.10. Calculated for Mn-Hg-py: Mn, 10.61; C, 32.47; H, 1.95; N, 16.23. Found: Mn, 10.40; C, 31.91; H, 2.00; N, 15.90. Infrared spectra of the compounds were recorded between 4000 and 300cm-’ on PerkinElmer 1330 and 621 spectrometers which were calibrated using an indene/camphor/cyclohexane standard solution. The samples were prepared as mulls (without grinding the finely powdered compounds) in nujol and hexachlorobutadiene between CsI windows (it is found that the compounds Mn-Cd-py and Mn-Hg-py are decomposed on grinding or under pressure during the preparation of the KBr discs). Raman spectra could not be obtained (by using the 488 or 515nm line) for the dark brown Mn-Cd-py and Mn-Hg-py compounds.
3. Results and discussion The IR spectra of the Mn-Cd-py and Mn-Hg-py compounds are given in Figs. la and b, respectively. Owing to the lack of structural data, the assignment was made by treating the pyridine molecule (C,,) and the Mu (Td) ions as isolated units. The wavenumbers and assignment of the observed bands in the infrared and Raman spectra of the complexes studied are given in Tables 1 and 2 for pyridine and
M(CN)4 ions, respectively, together with some pertinent spectral data for comparison. The spectral features of Mn-Cd-py, Mn-Hg-py, CdCd-py and Cd-Hg-py [l l] are found to be very similar, suggesting that they have isomorphous crystal structures. Vibrational spectra of pyridine and coordinated pyridine in metal complexes have been extensively studied by several workers. The most relevant work for our purpose is that of Akyiiz et al. [ 131. These authors presented infrared and Raman spectral data for a series of Hofmann-type pyridine complexes with the formula M(py)zNi(CN)d (M = Mn, Co, Fe, Ni, Cu, Zn and Cd). They made the assignment for coordinated pyridine by making a one-to-one comparison with the assignments for liquid pyridine (Table 1). On complexing, pyridine vibrational frequencies generally increase and At modes are most strongly perturbed. The upward shifts of several fundamental frequencies of pyridine in the complexes when compared to those of the free molecule were explained mainly in terms of coupling of the internal vibrational modes of the pyridine with the M-N vibrations. Their explanation was supported for in-plane modes by a simple normal coordinate analysis [13]. A glance at Table 1 shows that each of the fundamental frequencies in the spectra of Mn(py)zNi(CN)h and Cd(py)*Ni(CN)d is faithfully reproduced with only minor shifts in the spectra of the complexes studied. The striking correspondence between these frequencies suggests that the pyridine molecules in our complex coordinate to Mn. In the T&ype clathrates and host complexes studied previously [2,4,15], the metal atom M in M(CN)4 is tetrahedrally surrounded by the carbon ends of four CN ions. Therefore, it is reasonable to assume that the complexes studied here also have tetrahedral M(CN)d moeities. In assigning the bands attributable to M(CN)4 (M = Cd or Hg) ions in the spectra of our complexes, we refer to the work of Jones [16] who presented vibrational data for the salts KzCd(CN& and K2Hg(CN)4 in the solid state and assigned the infrared and Raman active fundamental vibrations of the isolated Cd(CN)4 and Hg(CN)4 ions on the basis of Td symmetry. These are given in Table 2 for com-
Z. Kantarci et al./J. Mol. Struct. 323 (1994)53-B
2500
s2.
2000
is00
1600
1200
lO@O
800
600
400
200
;).I -*--.~: Y
-.1
4000
t400
3soo
3000
2500
2000
1000
-.I__--L.----..-_.L..-_-
1600
hlAVENlJMBER
Fig. 1. IR spectra ofMn-Cd-py
(a) and Mn-Hg-py
I--.. SO0 600 -
1400
1200
1000
(@l-1)
(b) in nujol mulls. (*, in hexachiorobu~diene).
400
zoo
20 Y (CH)
A2
Y (CH) Y (CH) y ring Y (CH) y ring
+MN)
+40(riw)
40(kd
vdring)
249Ow)
40Ok
+725(fiw)
r+(ring) +&(ring)
47&H)
42CH)
1682 1633 1599 1357 1296
2454 2293
939 882 746 703 405
_
3079 3026 1574 1438 13.55 1235 1147 1068 650
3053 3053 3036 1582 1482 1217 1080 1029 990 604
_ _ _ _ _
_
404
942 886 749
374
-.
_
1638 _ _
_ _ _
_
_
_ _
749 690 415 696 417
943 868
384
946 872 748 690 413
946
-
2470 2304 1997 1979 1938 1693 1663 1638 1378 1303
947 874 751 691 411
_ _
_ _
_ -
_ _ _
1152 1065 652
1358 1236 1151 1068 650
3082 3018 1572 1443 1358 1236 1152 1068 651
3072 3020 1575 1446 1359 1240 1152 1065 655
3082 302 1 1575 1446 1356 1236 1152 1065 650
_ _
_ _ _
_ _
409
944 868 _
1572 _
3075
1036 1009 626
1600 1487 1221 _
3086 3018 1574 1445 1357
3069 3057
_ _ 3044 1597 1484 1217 1082 1036 1011 627
RaC
IRb
3065 3058 3035 1602 1485 1219 1085 103s 1014 629
Ro
3064 3056 3035 1603 1486 1217 1083 1037 1011 628
IR
Cd-Cd
3074 3061 3032 1602 1486 1218 1082 1036 1009 626
1218 1144 1069 652
1570 1438
_
1029 992 605
1580 1480 _ _
3054 _ _
IR
Ra
Cd-N?
in the complexes
IRa
of pyridine
MnNia
(cm-‘)
Pyridine (Liquid)
wavenumbers
2&&H) 2&7&H) VI (CH) +(CH) %(ring) f?23(CH)
23 24 25 26 27
22 y ring
a From Ref. 13. b From Ref. 11. ’ From Ref. 14.
B2
11 v(CH) 12 y(CH) 13 v ring 14vring l5vring 16 6(CH) 17 6(CH) 18 6(CH) 19 6 ring
RI
21 y(CH)
1 u(CH) 2 u(CH) 3 Y(CH) 4 Y ring 5 v ring 6 6(CH) 7 6(CH) Bvring 9 Y ring 10 6 ring
vibrational
Al
Assignments
Table 1 Fundamental
2470 2304 1997 1979 1938 1692 1663 1638 1378 1303
946 874 750 680 411
1236 1151 1068 651
3084 3018 1.572 1443
3044 1598 1486 1218 1082 1036 1009 627
lRb
Cd-Hg
948 _ -
1358 1236 1150 1068 650
1574 -
3076
1036 1010 628
1600 1488 1222
3070 3058 _
Rae
2470 2300 1995 1980 1922 1694 1663 1638 1375 1295
945 874 750 690 414
_
1152 1068 651
3090 3022 1574 1445 1355 _
1601 1488 1218 1082 1036 1009 625
2470 2300 1995 1980 1922 1693 1663 1638 1375 1295
944 862 750 690 411
_ _ _
1152 1068 651
3090 3020 1574 1445 1355 _
1601 1486 1218 1082 1036 1006 625
_ 3050 _
_
IR
Mn-Hg -
3050 _
IR
Mn-Cd -
m _
W -
W vs
W
W
m
VW
W
m
W
W
VW vw
VW
W S
m
W
m VW
W W
W S
-
W W S
W
W W
W
W _
W
m vs
W
m
Ra
m vs
W
m
s s m
W
S
S
VS
VW
VW
W
IR
Relative intensity
57
Z. Kantarci et al./J. Mol. Strucf. 323 (1994j 53-58
Table 2 The wavenumbers (cm-‘) of M(CN)4 group vibrations of the complexesa Assignments
SW) vz GN)
Ai
VI
E
q QMCN) v4 6(CMC)
Fz
vs u&N) Hot band v(‘~CN)
F?
Fl
vs
-
2183* _
fvs>
2170 _
2170
VS
_
W
2122
_
VW
(2149) (335)
(2177) -
2145
2146 _ _
(2172) 2173 2134 2124
(2170) 2173 2140
369 260
369 260 _
369 265 _
1920 _
1920 1814 1800
180
-v6
2183’ _
(2149) (324)
V~ s(CMC)
*I
Relative intensity
Cd-Cd-pyc
330 235 54
“1 -
Mn-Hg-py
K*Hg(CN),b
q, Y(MC) +G(MCN) V, v(MC) +6(MCN) vs QCMC)
_ _ _
Y
4
1920 1813 IS00
Cd-Hg-pyC
Mn-Cd-py
K,Cd(CN),b
_
1802
(ml
369 265
vs
1918 1811
W
S
_
1800
W W
a Raman bands are given in parentheses. b Taken from Ref. 16. ’ IR data are from Ref. I I and Raman data are from Ref. 14. * Assigned from combination bands.
parison with the assignments for M(CN)4 groups in our complexes. The assigned bands of the Mn(CN)4 unit of the complexes appear to be much higher than those for isolated M(CN)4 ions (Table 2). Such upward frequency shifts have been observed for Td-type [l 1,I 71 and Hofmann-type [13] compounds, in which both ends of the CN group are coordinated, and explained as the mechanical coupling of the internal modes of M(CN&, with the metal Cd-NC vibrations. It follows that the N-ends of the M(CN), units are also bound to an Mn atom in the complexes. The preceding discussion led us to draw the conclusion that the frameworks of the complexes Mn(py)zM(CN)b (M = Cd or Hg) are similar to those found in Hofmann-~~-type clathrate compounds.
4. Acknowledgments Thp nnthnrc m-e vrateflll
tn the
Ga7i
IJniversitv
Research Fund for purchase of the Jobin-Yuvon U 1000 spectrophotometer, and to a referee for very useful comments.
5. References [I] T. Iwamoto, M. Kiyoki and N. Matsuura, Bull. Chem. Sot. Jpn., 51(1978) 390. [2] R. Kuroda, Inorg. Nucl. Chem. Lett., 9 (1973) 13. [3] T. Iwamoto and D.F. Shriver, Inorg. Chem., 11 (1972) 2570. [4] T. Iwamoto, J. Mol. Struct., 75 (1981) 51. [S] T. Iwamoto, Chem. Lett., 723 (1973). [6] S. Nishikiori and T. Iwamoto, J. Incl. Phenom., 3 (1985) 283. [7) S. Nishikio~, T. Iwamoto and Y. Yoshino, Bull. Chem. Sot. Jpn., 53 (1980) 2336. [S] T. Iwamoto, M. Kiyoki, Y. Oh&u and Y. TokeshigeKato, Bull. Chem. Sot. Jpn., 51 (1978) 488. [9] E. Kasap, Ph.D. Thesis, Gazi University, Ankara, Turkev. 1992.
58
2. Kantarci et al./J. Mol. Struct. 323 (1994) 53-58
[lo] E. Kasap and Z. Kantarci, J. Incl. Phenom., submitted for publication. [ll] Z. Kantarci, Commun. Fat. Sci. Univ. Ankara, 37 (1988) 53. [12] H. Yuge and T. Iwamoto, J. Chem. Sot. Dalton Trans., 2841 (1993). [13] S. Akyiiz, A.B. Dempster and R.L. Morehouse, J. Mol. struct., 17 (1973) 105.
[14] Z. Kantarci, unpublished Raman data on Cd-Cd-py and Cd-Hg-py complexes (1993). [15] S. Nishikiori and T. Iwamoto, J. Incl. Phenom., 3 (1985) 283. [16] L.H. Jones, Spectrochim. Acta, 17 (1961) 188. [17] N. Ekici, Z. Kantarci and S. Akyiiz, J. Incl. Phenom., 10 (1991) 9.
MOLECULAR STRUCTURE
ELSEVIER
Journal of Molecular Structure 323 (1994) 53-58
Infrared spectroscopic studies on the Hofmann- T’&ype complexes: Mn(pyridine)~~d(C~)~ and Mn(pyridine)~Hg(C~~ Z. Kantarcia9*, N. Karacana, B. Davarcio@ub aGazi lhiversitesi, Fen Edebiyat Faktihesi, Teknikokdar, 06500 Ankara, Turkey bGazi ~~~vers~~esi, Fen Bilimieri EnstittW Teknikokullar, Ankara, Turkey
(First received 29 November 1993; in final form 4 February 1994)
Abstract Two new Hofmann-Td-type complexes, Mn(pyridine)$d(CN)4 and Mn(pyridine)zHg(CN)4, have been prepared and their infrared spectra are reported.
1. Introduction
Among Hofmann-type and analogous host frameworks, a group of complexes with the general formula CdL2M(CN)4, where L2 is a bidentate or a pair of monodentate ligand molecules containing N-donor atoms and M is Cd or Hg, is of special interest, since their structures act as excellent reservoirs for the thermally unstable chemical species such as cyclohexadienyl (C6H6) radicals [I]. In these compounds the host framework is formed from infinite -Cd-L2-Cd-L2chains extending along the a and b axes alternately and the tetrahedral M(CN), ions are arranged between the consecutive crossing -Cd-L&dLz- chains with the N-ends bound to the Cd atoms [2-81. This structure provides two kinds of cavities, a and p, for the guest molecules. The Q cavity has approximateiy the shape of a rectangular prism similar to those in Hofmann-type hosts, while the ,B cavity has the shape of a biprism, as *Correspondingauthor.
has been demonstrated in previous papers 12-41. The compounds possessing this type of host framework reported to date have only been confined to the Cd metal atom in an octahedral environment. Recently, Kasap [9] and Kasap and Kantarci [lo] prepared two novel Td-type benzene clathrates, Mn(NHs)2M(CN)4 - 2C6H6 (M = Cd or Hg). We have now prepared two new dipyridinemanganese (II) tetracyanometalate(I1) host complexes, Mn(pyridine)~M(CN)~ (M = Cd or Hg). In this study, the infrared spectroscopic results for Mn(II)(pyridine)zCd(II)(CN)4 (abbreviated to Mn-Cd-py) and Mn(II)(pyridine)zHg(II)(CN)4 (abbreviated to Mn-Hg-py~ are reported. For the purposes of comparison and discussion concerning the structure of these compounds, the infrared spectral data of the complex ~d(pyridine)~Cd(~N)~ (abbreviated to Cd-Cdpy) [I I] are quoted, since a single crystal X-ray structural study [12] has shown that this complex possesses a Hofmann-T&ype host framework.
0022-2860/94/$07.00 0 1994 Elsevier Science B.V. All rights reserved SSDZ 0022-2860(94)07985-J
54
Z. Kantarci et aLLI. Mol. Struct. 323 (f994j 53-58
2. Ex~~mental All chemicals used were reagent grade (Merck) and used without further purification. The complexes were prepared by adding slightly more than 2 mmoles of pyridine and 1 mmole of potassium tetracyanometalate solution in water to 1 mmole of Mn(I1) chloride solution in water. The brown precipitate was filtered, washed with water, ethanol and ether successively, and stored in a desiccator. The freshly prepared samples were analyzed for Mn and Cd with a Philips P49200 atomic absorption spectrophotometer, and for C, H and N with a Leco CHN-600 analyzer with the results as follows. Calculated for Mn-Cd-py: Mn, 12.79; Cd, 26.17; C, 39.14; H, 2.35; N, 19.56. Found: Mn, 12.89; Cd, 26.28; C, 38.60; H, 2.42; N, 19.10. Calculated for Mn-Hg-py: Mn, 10.61; C, 32.47; H, 1.95; N, 16.23. Found: Mn, 10.40; C, 31.91; H, 2.00; N, 15.90. Infrared spectra of the compounds were recorded between 4000 and 300cm-’ on PerkinElmer 1330 and 621 spectrometers which were calibrated using an indene/camphor/cyclohexane standard solution. The samples were prepared as mulls (without grinding the finely powdered compounds) in nujol and hexachlorobutadiene between CsI windows (it is found that the compounds Mn-Cd-py and Mn-Hg-py are decomposed on grinding or under pressure during the preparation of the KBr discs). Raman spectra could not be obtained (by using the 488 or 515nm line) for the dark brown Mn-Cd-py and Mn-Hg-py compounds.
3. Results and discussion The IR spectra of the Mn-Cd-py and Mn-Hg-py compounds are given in Figs. la and b, respectively. Owing to the lack of structural data, the assignment was made by treating the pyridine molecule (C,,) and the Mu (Td) ions as isolated units. The wavenumbers and assignment of the observed bands in the infrared and Raman spectra of the complexes studied are given in Tables 1 and 2 for pyridine and
M(CN)4 ions, respectively, together with some pertinent spectral data for comparison. The spectral features of Mn-Cd-py, Mn-Hg-py, CdCd-py and Cd-Hg-py [l l] are found to be very similar, suggesting that they have isomorphous crystal structures. Vibrational spectra of pyridine and coordinated pyridine in metal complexes have been extensively studied by several workers. The most relevant work for our purpose is that of Akyiiz et al. [ 131. These authors presented infrared and Raman spectral data for a series of Hofmann-type pyridine complexes with the formula M(py)zNi(CN)d (M = Mn, Co, Fe, Ni, Cu, Zn and Cd). They made the assignment for coordinated pyridine by making a one-to-one comparison with the assignments for liquid pyridine (Table 1). On complexing, pyridine vibrational frequencies generally increase and At modes are most strongly perturbed. The upward shifts of several fundamental frequencies of pyridine in the complexes when compared to those of the free molecule were explained mainly in terms of coupling of the internal vibrational modes of the pyridine with the M-N vibrations. Their explanation was supported for in-plane modes by a simple normal coordinate analysis [13]. A glance at Table 1 shows that each of the fundamental frequencies in the spectra of Mn(py)zNi(CN)h and Cd(py)*Ni(CN)d is faithfully reproduced with only minor shifts in the spectra of the complexes studied. The striking correspondence between these frequencies suggests that the pyridine molecules in our complex coordinate to Mn. In the T&ype clathrates and host complexes studied previously [2,4,15], the metal atom M in M(CN)4 is tetrahedrally surrounded by the carbon ends of four CN ions. Therefore, it is reasonable to assume that the complexes studied here also have tetrahedral M(CN)d moeities. In assigning the bands attributable to M(CN)4 (M = Cd or Hg) ions in the spectra of our complexes, we refer to the work of Jones [16] who presented vibrational data for the salts KzCd(CN& and K2Hg(CN)4 in the solid state and assigned the infrared and Raman active fundamental vibrations of the isolated Cd(CN)4 and Hg(CN)4 ions on the basis of Td symmetry. These are given in Table 2 for com-
Z. Kantarci et al./J. Mol. Struct. 323 (1994)53-B
2500
s2.
2000
is00
1600
1200
lO@O
800
600
400
200
;).I -*--.~: Y
-.1
4000
t400
3soo
3000
2500
2000
1000
-.I__--L.----..-_.L..-_-
1600
hlAVENlJMBER
Fig. 1. IR spectra ofMn-Cd-py
(a) and Mn-Hg-py
I--.. SO0 600 -
1400
1200
1000
(@l-1)
(b) in nujol mulls. (*, in hexachiorobu~diene).
400
zoo
20 Y (CH)
A2
Y (CH) Y (CH) y ring Y (CH) y ring
+MN)
+40(riw)
40(kd
vdring)
249Ow)
40Ok
+725(fiw)
r+(ring) +&(ring)
47&H)
42CH)
1682 1633 1599 1357 1296
2454 2293
939 882 746 703 405
_
3079 3026 1574 1438 13.55 1235 1147 1068 650
3053 3053 3036 1582 1482 1217 1080 1029 990 604
_ _ _ _ _
_
404
942 886 749
374
-.
_
1638 _ _
_ _ _
_
_
_ _
749 690 415 696 417
943 868
384
946 872 748 690 413
946
-
2470 2304 1997 1979 1938 1693 1663 1638 1378 1303
947 874 751 691 411
_ _
_ _
_ -
_ _ _
1152 1065 652
1358 1236 1151 1068 650
3082 3018 1572 1443 1358 1236 1152 1068 651
3072 3020 1575 1446 1359 1240 1152 1065 655
3082 302 1 1575 1446 1356 1236 1152 1065 650
_ _
_ _ _
_ _
409
944 868 _
1572 _
3075
1036 1009 626
1600 1487 1221 _
3086 3018 1574 1445 1357
3069 3057
_ _ 3044 1597 1484 1217 1082 1036 1011 627
RaC
IRb
3065 3058 3035 1602 1485 1219 1085 103s 1014 629
Ro
3064 3056 3035 1603 1486 1217 1083 1037 1011 628
IR
Cd-Cd
3074 3061 3032 1602 1486 1218 1082 1036 1009 626
1218 1144 1069 652
1570 1438
_
1029 992 605
1580 1480 _ _
3054 _ _
IR
Ra
Cd-N?
in the complexes
IRa
of pyridine
MnNia
(cm-‘)
Pyridine (Liquid)
wavenumbers
2&&H) 2&7&H) VI (CH) +(CH) %(ring) f?23(CH)
23 24 25 26 27
22 y ring
a From Ref. 13. b From Ref. 11. ’ From Ref. 14.
B2
11 v(CH) 12 y(CH) 13 v ring 14vring l5vring 16 6(CH) 17 6(CH) 18 6(CH) 19 6 ring
RI
21 y(CH)
1 u(CH) 2 u(CH) 3 Y(CH) 4 Y ring 5 v ring 6 6(CH) 7 6(CH) Bvring 9 Y ring 10 6 ring
vibrational
Al
Assignments
Table 1 Fundamental
2470 2304 1997 1979 1938 1692 1663 1638 1378 1303
946 874 750 680 411
1236 1151 1068 651
3084 3018 1.572 1443
3044 1598 1486 1218 1082 1036 1009 627
lRb
Cd-Hg
948 _ -
1358 1236 1150 1068 650
1574 -
3076
1036 1010 628
1600 1488 1222
3070 3058 _
Rae
2470 2300 1995 1980 1922 1694 1663 1638 1375 1295
945 874 750 690 414
_
1152 1068 651
3090 3022 1574 1445 1355 _
1601 1488 1218 1082 1036 1009 625
2470 2300 1995 1980 1922 1693 1663 1638 1375 1295
944 862 750 690 411
_ _ _
1152 1068 651
3090 3020 1574 1445 1355 _
1601 1486 1218 1082 1036 1006 625
_ 3050 _
_
IR
Mn-Hg -
3050 _
IR
Mn-Cd -
m _
W -
W vs
W
W
m
VW
W
m
W
W
VW vw
VW
W S
m
W
m VW
W W
W S
-
W W S
W
W W
W
W _
W
m vs
W
m
Ra
m vs
W
m
s s m
W
S
S
VS
VW
VW
W
IR
Relative intensity
57
Z. Kantarci et al./J. Mol. Strucf. 323 (1994j 53-58
Table 2 The wavenumbers (cm-‘) of M(CN)4 group vibrations of the complexesa Assignments
SW) vz GN)
Ai
VI
E
q QMCN) v4 6(CMC)
Fz
vs u&N) Hot band v(‘~CN)
F?
Fl
vs
-
2183* _
fvs>
2170 _
2170
VS
_
W
2122
_
VW
(2149) (335)
(2177) -
2145
2146 _ _
(2172) 2173 2134 2124
(2170) 2173 2140
369 260
369 260 _
369 265 _
1920 _
1920 1814 1800
180
-v6
2183’ _
(2149) (324)
V~ s(CMC)
*I
Relative intensity
Cd-Cd-pyc
330 235 54
“1 -
Mn-Hg-py
K*Hg(CN),b
q, Y(MC) +G(MCN) V, v(MC) +6(MCN) vs QCMC)
_ _ _
Y
4
1920 1813 IS00
Cd-Hg-pyC
Mn-Cd-py
K,Cd(CN),b
_
1802
(ml
369 265
vs
1918 1811
W
S
_
1800
W W
a Raman bands are given in parentheses. b Taken from Ref. 16. ’ IR data are from Ref. I I and Raman data are from Ref. 14. * Assigned from combination bands.
parison with the assignments for M(CN)4 groups in our complexes. The assigned bands of the Mn(CN)4 unit of the complexes appear to be much higher than those for isolated M(CN)4 ions (Table 2). Such upward frequency shifts have been observed for Td-type [l 1,I 71 and Hofmann-type [13] compounds, in which both ends of the CN group are coordinated, and explained as the mechanical coupling of the internal modes of M(CN&, with the metal Cd-NC vibrations. It follows that the N-ends of the M(CN), units are also bound to an Mn atom in the complexes. The preceding discussion led us to draw the conclusion that the frameworks of the complexes Mn(py)zM(CN)b (M = Cd or Hg) are similar to those found in Hofmann-~~-type clathrate compounds.
4. Acknowledgments Thp nnthnrc m-e vrateflll
tn the
Ga7i
IJniversitv
Research Fund for purchase of the Jobin-Yuvon U 1000 spectrophotometer, and to a referee for very useful comments.
5. References [I] T. Iwamoto, M. Kiyoki and N. Matsuura, Bull. Chem. Sot. Jpn., 51(1978) 390. [2] R. Kuroda, Inorg. Nucl. Chem. Lett., 9 (1973) 13. [3] T. Iwamoto and D.F. Shriver, Inorg. Chem., 11 (1972) 2570. [4] T. Iwamoto, J. Mol. Struct., 75 (1981) 51. [S] T. Iwamoto, Chem. Lett., 723 (1973). [6] S. Nishikiori and T. Iwamoto, J. Incl. Phenom., 3 (1985) 283. [7) S. Nishikio~, T. Iwamoto and Y. Yoshino, Bull. Chem. Sot. Jpn., 53 (1980) 2336. [S] T. Iwamoto, M. Kiyoki, Y. Oh&u and Y. TokeshigeKato, Bull. Chem. Sot. Jpn., 51 (1978) 488. [9] E. Kasap, Ph.D. Thesis, Gazi University, Ankara, Turkev. 1992.
58
2. Kantarci et al./J. Mol. Struct. 323 (1994) 53-58
[lo] E. Kasap and Z. Kantarci, J. Incl. Phenom., submitted for publication. [ll] Z. Kantarci, Commun. Fat. Sci. Univ. Ankara, 37 (1988) 53. [12] H. Yuge and T. Iwamoto, J. Chem. Sot. Dalton Trans., 2841 (1993). [13] S. Akyiiz, A.B. Dempster and R.L. Morehouse, J. Mol. struct., 17 (1973) 105.
[14] Z. Kantarci, unpublished Raman data on Cd-Cd-py and Cd-Hg-py complexes (1993). [15] S. Nishikiori and T. Iwamoto, J. Incl. Phenom., 3 (1985) 283. [16] L.H. Jones, Spectrochim. Acta, 17 (1961) 188. [17] N. Ekici, Z. Kantarci and S. Akyiiz, J. Incl. Phenom., 10 (1991) 9.