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Pyrophthalone and its derivatives as ligands—I. Mode of coordination—formation of isomeric iminopyrophthalone complexes
Polyhehn Vol. 5, No. 12, pp. 198W986, Printed in Great Britain
1986 0
0277-5387/86 S3.00+.00 1986 Pergamon Journals Ltd
PYROPHTHALONE AND ITS DERIVATIVES AS LIGANDS-I. MODE OF COORDINATION-FORMATION OF ISOMERIC IMINOPYROPHTHALONE COMPLEXES M. MITEWA
and P. R. BONTCHEV*
Department of Chemistry, University of Sofia, 1126 Sofia, Bulgaria M. KASHCHIEVA
and S. MINCHEV
High Pedagogical Institute, Shoumen, Bulgaria V. BARDAROV Institute of Hygiene and Occupational Health, Sofia, Bulgaria and G. WERNER Department of Chemistry, Karl Marx University, Leipzig, G.D.R. (Received 25 March 1986 ; accepted 7 May 1986)
Abstract-The complex formation of Co(II), Ni(II), Zn(I1) with aminopyrophthalone was studied by means of electronic, IR, EPR and ‘H-NMR spectroscopy. It was established that with Co(I1) and Ni(I1) two isomeric complexes are formed in contrast to Zn(I1) and Cu(I1) complex formation. On the basis of the spectral data obtained the coordination mode and structure of the complex species are assumed.
We have already studied the complexation properties of some derivatives of 1,3-indandione, namely of 2-(2-pyridyl)- 1,3-indandione or pyrophthalone (PPH), 2-(2-quinolyl)- 1,3-indandione or quinophthalone (QPH) and 3-amino-2-(2-pyridyl)indenone or iminopyrophthalone (IPH) towards some transition metal ions.ie3 These ligands are used as dyes, organic semiconductors, and anti-inflammatory and anaesthetic agents.“8 The structure of the pyrophthalone and iminopyrophthalone complexes with Cu(II)--one of the most important biometals, was studied in detail.‘*2 In the present paper the results obtained for the Co(II), Ni(I1) and Zn(I1) complexes of iminopyrophthalone are reported, emphasizing mainly the mode of coordination of the ligand.
“Specord 71 IR”, VEB Carl Zeiss-Jena and Perkin-Elmer 983 (CsI discs, spectral range 4000-200 cm-‘). The EPR spectra were recorded on X-band EPR-spectrometer ERS-220 (G.D.R.), the ‘H-NMR on FT-NMR spectrometer “Bruker WP-200”. The HPLC experiments were performed on Perkin-Elmer LC system consisting of a series of four solvent delivery system connected with 8-~1 flow cell of 550 SE UV-Vis spectrometer. Synthetic procedures
IPH was obtained and purified as described previously.’ The complexes Co(IP),, Ni(IP)2 and Zn(IP), were obtained in slightly acidic medium (pH - 4-5) mixing ethanolic solution of IPH EXPERIMENTAL (5 x 10e3 M) with water solution of the corresThe electronic and IR spectra were obtained ponding metal salt w”C12 or M”(NO,)d at 40°C on recording spectrometers “Specord UVvi?, (metal to ligand ratio 1: 2). The corresponding complexes were precipitated after careful neutralization *Author to whom correspondence should he addressed of the solution with 0.1 M NaOH. The products 1983
M. MITEWA et al.
1984
Table 1. Analytical and electronic spectral data % Me”
%N Comp.
talc.
found
talc.
found
IZ,,,,brun
IPH
12.6
12.8 12.7
Co(lP)*
11.2
10.9 10.8
11.7
11.4
330; 350; 398
Ni(IP),
11.2
10.9 10.8
11.7
11.5
336; 348
Zn(lP),
11.0
11.5 11.6
12.9
12.4
336; 348; 380
333; 352
‘Average of three measurements. bSolvent acetonitrile (An).
1: 2. Their formation is connected with the appearance of a new band in the visible spectra of the complexes (see Table 1). In order to obtain some structural information IR, EPR and ‘H-NMR investigations were provided. In Table 2 the IR data obtained for the complexes studied together with that for Cu(IP)*’ are presented. It is evident that the IR spectral data for Zn(IP)* are very similar to that of Cu(IP),, showing a similarity of their mode of coordination as well. For Cu(IP)* chelation through enolic oxygen and nitrogen atom from the pyridyl ring (str. I) has been found. By means of EPR and magnetic susceptibility data a depressed tetrahedral or rhombic symmetry with slightly mis-aligned tetragonal axes was assumed.‘*’
were filtered off, washed with ethanol and dried for a week over P205 under low pressure. Analytical
data
Elemental analysis of N was provided according to Kjeldahl (treatment for 12 h). Nickel and zinc were determined complexometrically at pH 10 and indicators murexide for nickel and eriochrom T for zinc after ashing the sample and dissolving the residue in HN03 (2: 1). Cobalt was determined photometrically with nitroso-R-salt at 1= 500 nm after wet oxidative destruction of the sample with cont. HN03, evaporation near dryness and dissolving the residue in water. RESULTS
AND DISCUSSION
The analytical data obtained show that the complexes thus formed have a metal to ligand ratio of
II
I
The IR data for the Co(I1) and Ni(I1) complexes show the simultaneous presence of carbonyl, iminoand amino (v’ and vas) vibrations. Therefore simultaneous formation of two isomeric complexes (str. I and II) of Co(I1) and Ni(I1) should be assumed. These results are in agreement with the HPLC and ‘H-NMR data obtained. The chromatograms of Cu(I1) and Zn(I1) complexes show one single peak, while these of Co(I1) and Ni(I1) complexes show two peaks (Fig. l), thus suggesting the presence of two isomeric species. The ‘H-NMR data obtained for Ni(IP)2 and Zn(IP), in the range O-20 ppm together with that
Table 2. Selected IR data for IPH and its complexes IPH (cm - ‘)
Co(IP)* (cm-‘)
Ni(IP)* (em-‘)
Cu(lP)* (cm-‘)
Zn(lP), (cm- ‘)
1500s 1515s 1590s 1620s 1730m 3150 m
1480s 1565s 1610s 1650m 1728m 3230 br
1475s 1565 s 1595 s 1620sh 1640 sh 1725s
1490s 1535s I 1555 s 1575m 1610m 1640m -
3320 m
3430 br
3200 br 3400 v.br
1488 s 1552s 1602s 1650m -
3240 w
3280 w
-
s = strong; m z medium; sh = shoulder.
-
Vibrations of the phthalone system* Vet v-’ %I
-
3280 m
w z weak;
Assignment
@&I,
3290 m
br E broad;
1.9
1.10 21,10
v,NH”9
v.br = very
broad;
1985
Pyrophthalone and its derivatives as ligandeI Table 3. ‘H-NMR data (solvent DMSO-d,) Compound
Hz d 8.39 8.43
H,
I-L
tr
6.96 7.00 7.03
7:2 7.80 7.78 7.76
d 9.08 9.12
tr 6.92 6.94 6.98
d 7.78 7.79
9.12
9.;2
H,
H 6/g
H 7/s
NH2 =NH
d 8.45 8.47
7%
7Y4
d 9.26 10.23
& d 7.70 7.71
8.;3
6.s96 7.:4
8.541 7.64 s
9.:0
6.96 S
8.41 S
7.74 S
8.s30
-
I%
7.‘64 9.:8
7:o
-
Ii.1
7.:2
-
10.2 S
7.“39 14.4 d 14.88
-
s = singlet, d = doublet, tr = triplet, q = quartet, m = multiplet. of IPH were assigned’ and summarized in Table 3. They are also consistent with the conclusions made above. The comparison of IPH and Zn(IP), spectra indicates on the Zn(I1) chelation through enolic oxygen and nitrogen from pyridyl ring. In Zn(IP)* spectrum instead of NH2 doublet at 9.26 and 10.23 ppm’ a new peak at 10.1 ppm due to =NH group appears. The doublet of Hz proton is strongly shifted and the multiplet due to H6,9protons is affected as well, namely a doublet at 7.70 ppm is observed, assigned to the Hs proton and the new peak at 8.93 ppm should be assigned to the Hg proton. The shifts of the H2 and Hg protons signals indicates the coordination of Zn(II) to the neighbouring N- and Oatoms respectively. In the Ni(IP)2 spectrum a greater number of signals is observed. A new low-field doublet (14.4 and 14.9 ppm) is present due most probably to coordinated NH2 group and an =NH singlet is also
observed indicating the presence of the other isomer. In this case. the H2 proton neighbouring the pyridyl nitrogen is also shifted as well as the signals due to H, and Hp. For H9 two different peaks are observed, due most probably to the Hg protons of the two isomers. The EPR study of the Co(IP), complex [powder sample, diamagnetically diluted with Zn(IP)d in the range 700-5700 Oe at - 190°C showed that only one almost isotropic singlet line @ = 2.002 &-0.001) was observed, thus proving the oxidation state +2 for the complex. According to the literature data” the EPR results show that for the Co(IP), complex a planar structure seems more likely than a tetrahedral one. The fact that Co(I1) and Ni(I1) are forming two isomeric complexes with IPH in contrast to Cu(I1) and Zn(II) is rather surprising taking into account the very close values of their ionic radii.12 Most probably the simultaneous formation of the two
1986
M. MITEWA Zn(lP),
COUP)2
Ni (IP)z
et al.
different types of complexes with Co(I1) and Ni(I1) is due to a proper steric orientation and energy level of the nitrogen atom orbitals of NH2 group, for which overlapping with d-orbitals only of Co(I1) and Ni(I1) is possible.
CuUP)z
REFERENCES
Ih Fig. 1. HPLC data. PE-analytical column (25 cm x 4.6 mm). HC-ODS (10 p), isocratic separation with mobile phase An : water (60% : 40%), 1 ml/min. Spectrophotometric detection at 1= 210 nm.
1. P. R. Bontchev, M. Mitewa, S. Minshev, M. Kashchieva and D. Mechandjiev, J. Prakt. Chem. 1983, 325, 803. 2. M. Mitewa, P. R. Bontchev, A. Malinovski, M. Kashchieva and S. Minchev, C. r. Acad. Bulg. Sci. 1983,36,1311. 3. M. Mitewa, P. R. Bontchev, V. Enchev, S. Minchev and M. Kashchieva, J. Prakt. Chem. 1985,327,516. 4. B. K. Manukian and A. Mangini, Chimia 1970, 24, 382. 5. M. Tomanek-Kunitzer, F.R.D.-patent No. 1265582 (1968). 6. J. Ploquin, L. Sparfel, G. le Bant, L. Welin, I. Y. Petit and N. Henry, Chim. Ther. 1973,350. 7. G. le Bant, L. Sparfel, J. Ploquin, I. Y. Petit, N. Henry and L. Welin, Bull. Sot. Pharm. de 1’Ouest 1973, 15,43. 8. I. J. Neiland and J. J. Katzen, Khim. Geterozikl. Soed. 1975,435. 9. J. F. Freimanis and G. J. Vanag, J. Obsch. Khim. 1964, 34, 452. 10. K. Nakamoto, Infrared and Raman Spectra of Znorganic and Coordination Compounds, 3rd edn. Wiley Interscience, New York (1978). 11. H. A. Kuska and M. T. Rogers, Electron Spin Resonance of First Row Transition Metal Complex Ion. Wiley Interscience, New York (1968). 12. L. Ahrens, Geochim. Cosmochim. Acta 1952,2, 155.
1986 0
0277-5387/86 S3.00+.00 1986 Pergamon Journals Ltd
PYROPHTHALONE AND ITS DERIVATIVES AS LIGANDS-I. MODE OF COORDINATION-FORMATION OF ISOMERIC IMINOPYROPHTHALONE COMPLEXES M. MITEWA
and P. R. BONTCHEV*
Department of Chemistry, University of Sofia, 1126 Sofia, Bulgaria M. KASHCHIEVA
and S. MINCHEV
High Pedagogical Institute, Shoumen, Bulgaria V. BARDAROV Institute of Hygiene and Occupational Health, Sofia, Bulgaria and G. WERNER Department of Chemistry, Karl Marx University, Leipzig, G.D.R. (Received 25 March 1986 ; accepted 7 May 1986)
Abstract-The complex formation of Co(II), Ni(II), Zn(I1) with aminopyrophthalone was studied by means of electronic, IR, EPR and ‘H-NMR spectroscopy. It was established that with Co(I1) and Ni(I1) two isomeric complexes are formed in contrast to Zn(I1) and Cu(I1) complex formation. On the basis of the spectral data obtained the coordination mode and structure of the complex species are assumed.
We have already studied the complexation properties of some derivatives of 1,3-indandione, namely of 2-(2-pyridyl)- 1,3-indandione or pyrophthalone (PPH), 2-(2-quinolyl)- 1,3-indandione or quinophthalone (QPH) and 3-amino-2-(2-pyridyl)indenone or iminopyrophthalone (IPH) towards some transition metal ions.ie3 These ligands are used as dyes, organic semiconductors, and anti-inflammatory and anaesthetic agents.“8 The structure of the pyrophthalone and iminopyrophthalone complexes with Cu(II)--one of the most important biometals, was studied in detail.‘*2 In the present paper the results obtained for the Co(II), Ni(I1) and Zn(I1) complexes of iminopyrophthalone are reported, emphasizing mainly the mode of coordination of the ligand.
“Specord 71 IR”, VEB Carl Zeiss-Jena and Perkin-Elmer 983 (CsI discs, spectral range 4000-200 cm-‘). The EPR spectra were recorded on X-band EPR-spectrometer ERS-220 (G.D.R.), the ‘H-NMR on FT-NMR spectrometer “Bruker WP-200”. The HPLC experiments were performed on Perkin-Elmer LC system consisting of a series of four solvent delivery system connected with 8-~1 flow cell of 550 SE UV-Vis spectrometer. Synthetic procedures
IPH was obtained and purified as described previously.’ The complexes Co(IP),, Ni(IP)2 and Zn(IP), were obtained in slightly acidic medium (pH - 4-5) mixing ethanolic solution of IPH EXPERIMENTAL (5 x 10e3 M) with water solution of the corresThe electronic and IR spectra were obtained ponding metal salt w”C12 or M”(NO,)d at 40°C on recording spectrometers “Specord UVvi?, (metal to ligand ratio 1: 2). The corresponding complexes were precipitated after careful neutralization *Author to whom correspondence should he addressed of the solution with 0.1 M NaOH. The products 1983
M. MITEWA et al.
1984
Table 1. Analytical and electronic spectral data % Me”
%N Comp.
talc.
found
talc.
found
IZ,,,,brun
IPH
12.6
12.8 12.7
Co(lP)*
11.2
10.9 10.8
11.7
11.4
330; 350; 398
Ni(IP),
11.2
10.9 10.8
11.7
11.5
336; 348
Zn(lP),
11.0
11.5 11.6
12.9
12.4
336; 348; 380
333; 352
‘Average of three measurements. bSolvent acetonitrile (An).
1: 2. Their formation is connected with the appearance of a new band in the visible spectra of the complexes (see Table 1). In order to obtain some structural information IR, EPR and ‘H-NMR investigations were provided. In Table 2 the IR data obtained for the complexes studied together with that for Cu(IP)*’ are presented. It is evident that the IR spectral data for Zn(IP)* are very similar to that of Cu(IP),, showing a similarity of their mode of coordination as well. For Cu(IP)* chelation through enolic oxygen and nitrogen atom from the pyridyl ring (str. I) has been found. By means of EPR and magnetic susceptibility data a depressed tetrahedral or rhombic symmetry with slightly mis-aligned tetragonal axes was assumed.‘*’
were filtered off, washed with ethanol and dried for a week over P205 under low pressure. Analytical
data
Elemental analysis of N was provided according to Kjeldahl (treatment for 12 h). Nickel and zinc were determined complexometrically at pH 10 and indicators murexide for nickel and eriochrom T for zinc after ashing the sample and dissolving the residue in HN03 (2: 1). Cobalt was determined photometrically with nitroso-R-salt at 1= 500 nm after wet oxidative destruction of the sample with cont. HN03, evaporation near dryness and dissolving the residue in water. RESULTS
AND DISCUSSION
The analytical data obtained show that the complexes thus formed have a metal to ligand ratio of
II
I
The IR data for the Co(I1) and Ni(I1) complexes show the simultaneous presence of carbonyl, iminoand amino (v’ and vas) vibrations. Therefore simultaneous formation of two isomeric complexes (str. I and II) of Co(I1) and Ni(I1) should be assumed. These results are in agreement with the HPLC and ‘H-NMR data obtained. The chromatograms of Cu(I1) and Zn(I1) complexes show one single peak, while these of Co(I1) and Ni(I1) complexes show two peaks (Fig. l), thus suggesting the presence of two isomeric species. The ‘H-NMR data obtained for Ni(IP)2 and Zn(IP), in the range O-20 ppm together with that
Table 2. Selected IR data for IPH and its complexes IPH (cm - ‘)
Co(IP)* (cm-‘)
Ni(IP)* (em-‘)
Cu(lP)* (cm-‘)
Zn(lP), (cm- ‘)
1500s 1515s 1590s 1620s 1730m 3150 m
1480s 1565s 1610s 1650m 1728m 3230 br
1475s 1565 s 1595 s 1620sh 1640 sh 1725s
1490s 1535s I 1555 s 1575m 1610m 1640m -
3320 m
3430 br
3200 br 3400 v.br
1488 s 1552s 1602s 1650m -
3240 w
3280 w
-
s = strong; m z medium; sh = shoulder.
-
Vibrations of the phthalone system* Vet v-’ %I
-
3280 m
w z weak;
Assignment
@&I,
3290 m
br E broad;
1.9
1.10 21,10
v,NH”9
v.br = very
broad;
1985
Pyrophthalone and its derivatives as ligandeI Table 3. ‘H-NMR data (solvent DMSO-d,) Compound
Hz d 8.39 8.43
H,
I-L
tr
6.96 7.00 7.03
7:2 7.80 7.78 7.76
d 9.08 9.12
tr 6.92 6.94 6.98
d 7.78 7.79
9.12
9.;2
H,
H 6/g
H 7/s
NH2 =NH
d 8.45 8.47
7%
7Y4
d 9.26 10.23
& d 7.70 7.71
8.;3
6.s96 7.:4
8.541 7.64 s
9.:0
6.96 S
8.41 S
7.74 S
8.s30
-
I%
7.‘64 9.:8
7:o
-
Ii.1
7.:2
-
10.2 S
7.“39 14.4 d 14.88
-
s = singlet, d = doublet, tr = triplet, q = quartet, m = multiplet. of IPH were assigned’ and summarized in Table 3. They are also consistent with the conclusions made above. The comparison of IPH and Zn(IP), spectra indicates on the Zn(I1) chelation through enolic oxygen and nitrogen from pyridyl ring. In Zn(IP)* spectrum instead of NH2 doublet at 9.26 and 10.23 ppm’ a new peak at 10.1 ppm due to =NH group appears. The doublet of Hz proton is strongly shifted and the multiplet due to H6,9protons is affected as well, namely a doublet at 7.70 ppm is observed, assigned to the Hs proton and the new peak at 8.93 ppm should be assigned to the Hg proton. The shifts of the H2 and Hg protons signals indicates the coordination of Zn(II) to the neighbouring N- and Oatoms respectively. In the Ni(IP)2 spectrum a greater number of signals is observed. A new low-field doublet (14.4 and 14.9 ppm) is present due most probably to coordinated NH2 group and an =NH singlet is also
observed indicating the presence of the other isomer. In this case. the H2 proton neighbouring the pyridyl nitrogen is also shifted as well as the signals due to H, and Hp. For H9 two different peaks are observed, due most probably to the Hg protons of the two isomers. The EPR study of the Co(IP), complex [powder sample, diamagnetically diluted with Zn(IP)d in the range 700-5700 Oe at - 190°C showed that only one almost isotropic singlet line @ = 2.002 &-0.001) was observed, thus proving the oxidation state +2 for the complex. According to the literature data” the EPR results show that for the Co(IP), complex a planar structure seems more likely than a tetrahedral one. The fact that Co(I1) and Ni(I1) are forming two isomeric complexes with IPH in contrast to Cu(I1) and Zn(II) is rather surprising taking into account the very close values of their ionic radii.12 Most probably the simultaneous formation of the two
1986
M. MITEWA Zn(lP),
COUP)2
Ni (IP)z
et al.
different types of complexes with Co(I1) and Ni(I1) is due to a proper steric orientation and energy level of the nitrogen atom orbitals of NH2 group, for which overlapping with d-orbitals only of Co(I1) and Ni(I1) is possible.
CuUP)z
REFERENCES
Ih Fig. 1. HPLC data. PE-analytical column (25 cm x 4.6 mm). HC-ODS (10 p), isocratic separation with mobile phase An : water (60% : 40%), 1 ml/min. Spectrophotometric detection at 1= 210 nm.
1. P. R. Bontchev, M. Mitewa, S. Minshev, M. Kashchieva and D. Mechandjiev, J. Prakt. Chem. 1983, 325, 803. 2. M. Mitewa, P. R. Bontchev, A. Malinovski, M. Kashchieva and S. Minchev, C. r. Acad. Bulg. Sci. 1983,36,1311. 3. M. Mitewa, P. R. Bontchev, V. Enchev, S. Minchev and M. Kashchieva, J. Prakt. Chem. 1985,327,516. 4. B. K. Manukian and A. Mangini, Chimia 1970, 24, 382. 5. M. Tomanek-Kunitzer, F.R.D.-patent No. 1265582 (1968). 6. J. Ploquin, L. Sparfel, G. le Bant, L. Welin, I. Y. Petit and N. Henry, Chim. Ther. 1973,350. 7. G. le Bant, L. Sparfel, J. Ploquin, I. Y. Petit, N. Henry and L. Welin, Bull. Sot. Pharm. de 1’Ouest 1973, 15,43. 8. I. J. Neiland and J. J. Katzen, Khim. Geterozikl. Soed. 1975,435. 9. J. F. Freimanis and G. J. Vanag, J. Obsch. Khim. 1964, 34, 452. 10. K. Nakamoto, Infrared and Raman Spectra of Znorganic and Coordination Compounds, 3rd edn. Wiley Interscience, New York (1978). 11. H. A. Kuska and M. T. Rogers, Electron Spin Resonance of First Row Transition Metal Complex Ion. Wiley Interscience, New York (1968). 12. L. Ahrens, Geochim. Cosmochim. Acta 1952,2, 155.