Paramagnetic octahedral p-methoxyphenyldithiophosphonato nickel(II) complexes: Crystal structures of [Ni{S2P(OR)(p-CH3O-C 6H4)-κS,S′}2(L-κN) 2] (R = Et, 2,4-tBu2C

Article abstract of DOI:10.1002/zaac.200400053

The square-planar Ni^II complexes [Ni{S₂P(OR)(p- CH₃O-C₆H₄)-κS,S′}₂] react with 3-acetylpyridine to give green crystals of the paramagnetic octahedral complexes [Ni{S₂P(OR)(p-CH

Full text of DOI:10.1002/zaac.200400053

Paramagnetic Octahedral p-Methoxyphenyldithiophosphonato Nickel(II)
Complexes: Crystal Structures of [Ni{S2P(OR)(p-CH3O-C6H4)-κS,SЈ}2(L-κN)2]
(R ؍ Et, 2,4-tBu2C6H3, L ؍ 3-acetylpyridine)
Mehmet Karakusa,*, Peter Lönneckeb and Evamarie Hey-Hawkinsb,*
a Denizli/Turkey, Department of Chemistry, Pamukkale University
b Leipzig/Germany, Institut für Anorganische Chemie der Universität
Received February 19th, 2004.
Dedicated to Professor Reinhard Schmutzler on the Occasion of his 70th Birthday
Abstract. The square-planar NiII complexes [Ni{S2P(OR)(p-CH3O-
C6H4)-κS,SЈ}2] react with 3-acetylpyridine to give green crystals
of the paramagnetic octahedral complexes [Ni{S2P(OR)(p-CH3O-
and UV-vis spectroscopy, and crystal structures were determined
for 1 and 3. The magnetic moments for 1-3 are 3.04-3.15 B.M.
i
C6H4)-κS,SЈ}2(L-κN)2] [R ϭ Et (1), Pr (2), 2,4-tBu2C6H3 (3); L ϭ
Keywords: Dithiophosphonates; Octahedral paramagnetic nickel(II)
3-acetylpyridine]. Complexes 1-3 were characterized by IR, MS,
complexes
Paramagnetische oktaedrische p-Methoxyphenyldithiophosphonato-nickel(II)-
Komplexe: Molekülstrukturen von [Ni{S2P(OR)(p-CH3O-C6H4)-κS,SЈ}2(L-κN)2]
(R ؍ Et, 2,4-tBu2C6H3, L ؍ 3-Acetylpyridin)
Inhaltsübersicht.
Die
planar-quadratischen
NiII-Komplexe
2,4-tBu2C6H3 (3), L ϭ 3-Acetylpyridin]. Die Verbindungen 1-3
wurden durch IR- und UV-Vis-Spektroskopie, Massenspektrome-
trie und 1 und 3 auch durch Röntgenstrukturanalyse charakterisert.
Das magnetische Moment von 1-3 beträgt 3.04-3.15 B.M.
[Ni{S2P(OR)(p-CH3O-C6H4)-κS,SЈ}2] reagieren mit 3-Acetylpyri-
din zu den grünen paramagnetischen oktaedrischen Komplexen
[Ni{S2P(OR)(p-CH3O-C6H4)-κS,SЈ}2(L-κN)2] [R ϭ Et (1), Pr (2),
i
1 Introduction
ligands [8, 10, 12]. These coordinatively unsaturated com-
plexes react with donor molecules (L) to give paramagnetic
Complexes with dithiophosphato [(RO)2PS2Ϫ] [1, 2, 3, 4],
dithiophosphinato (R2PS2Ϫ) [4, 5] and dithiophosphonato
[RЈ(RO)PS2Ϫ] [4, 6, 7, 8, 9, 10, 11, 12, 13] ligands have been
utilized as insectizides, pestizides, flotation agents for min-
eral ores, solvent extraction reagents for metal ions and
antioxidants. In the last few decades, many complexes with
dithiophosphato and dithiophosphinato ligands were re-
ported, but the number of dithiophosphonato complexes is
limited because their synthesis is somewhat more challeng-
ing. Examples for the latter are the square-planar NiII di-
thiophosphonato complexes [Ni{S2P(OR)(p-CH3O-C6H4)-
κS,SЈ}2] in which the dithiophosphonates act as bidentate
octahedral
NiII
dithiophosphonato
complexes
[Ni{S2P(OR)(p-CH3O-C6H4)-κS,SЈ}2(L)2]. Only a few com-
plexes of this type are known up to now [8].
We now report the synthesis and spectroscopic properties
of the paramagnetic octahedral complexes [Ni{S2P(OR)(p-
i
CH3O-C6H4)-κS,SЈ}2(L-κN)2] [R ϭ Et (1), Pr (2), 2,4-
tBu2C6H3 (3); L ϭ 3-acetylpyridine].
2 Results and Discussion
2.1 Synthesis and properties
The octahedral NiII dithiophosphonato complexes
[Ni{S2P(OR)(p-CH3O-C6H4)-κS,SЈ}2(L-κN)2] [R ϭ Et (1),
iPr (2), 2,4-tBu2C6H3 (3); L ϭ 3-acetylpyridine] were pre-
pared by treating the square-planar NiII dithiophosphonato
complexes [Ni{S2P(OR)(p-CH3O-C6H4)-κS,SЈ}2] [10, 12]
with 3-acetylpyridine in CH2Cl2/EtOH (3/1), as shown in
Scheme 1. Complexes 1-3 are air-stable, slightly hygroscopic
solids, but over several weeks they lose 3-acetylpyridine and
reform the square-planar starting materials. They dissolve
in CHCl3 or CH2Cl2 to give purple solutions, indicative of
square-planar nickel(II) complexes. However, 31P NMR
spectra of these solutions could not be obtained (even at
* Prof. Dr. Evamarie Hey-Hawkins
Institut für Anorganische Chemie, Universität Leipzig
Johannisallee 29, D-04103 Leipzig, Germany
Tel.: ϩ49 (0) 341/9736151
Fax: ϩ49 (0) 341/9739319
E-mail: hey@rz.uni-leipzig.de
Dr. Mehmet Karakus
Department of Chemistry, Faculty of Arts and Science
Pamukkale University, Kinikli, 20017 Denizli, Turkey
Tel.: ϩ90 (0) 258/2134030
Fax: ϩ90 (0) 258/2125546
E-Mail: mkarakus@pamukkale.edu.tr
Z. Anorg. Allg. Chem. 2004, 630, 1249Ϫ1252
DOI: 10.1002/zaac.200400053
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M. Karakus, P. Lönnecke, E. Hey-Hawkins
low temperature), and this indicates an equilibrium between
the six- and four-coordinate complexes, as was also ob-
served for related complexes [8].
Complexes 1-3 were characterized by elemental analysis
(C, H, N, S), IR and UV-vis spectroscopy and mass spec-
trometry, and their magnetic moments were determined.
Structural characterization of complexes 1 and 3 revealed
axial coordination of two N-bonded monodentate 3-acetyl-
pyridine ligands in octahedral NiII complexes. 2-Acetylpyri-
dine does not react with [Ni{S2P(OR)(p-CH3O-C6H4)-
κS,SЈ}2], presumably due to steric hindrance.
Figure 1 Molecular structure of 1 (ORTEP, 50 % probability,
SHELXTL PLUS; XP [15], hydrogen atoms omitted for clarity).
Scheme 1
The IR spectra of complexes 1-3 show two bands at ca.
546 cmϪ1 and ca. 647 cmϪ1, assigned to νsym(PS2) and
νasym(PS2) vibrations, respectively [9]. The bands at about
1020 cmϪ1 can usually be assigned to the ν(PO) vibrations
[13]. The mass spectra of 1, 2 and 3 did not display molecu-
lar ion peaks (expected m/z 795, 873 and 1116); only the
peaks arising from loss of two 3-acetylpyridine molecules
i
are observed (m/z 552.3 (R ϭ Et), 580.4 (R ϭ Pr), and
872.7 (R ϭ 2,4-tBu2C6H3) for the corresponding nickel
complexes [Ni{S2P(OR)(p-CH3O-C6H4)-κS,SЈ}2]).
Figure 2 Molecular structure of 3 (ORTEP, 50 % probability,
SHELXTL PLUS; XP [15], hydrogen atoms omitted for clarity).
2.2 Molecular structures of 1 and 3
Crystals of 1 and 3 were obtained from CH2Cl2/EtOH. The
compounds crystallize in the monoclinic space group P21/c
with two centrosymmetric molecules in the unit cell. The
nickel atom lies on a crystallographic center of inversion.
In 1 (Fig. 1) and 3 (Fig. 2) the NiII ion is octahedrally coor-
dinated by two bidentate dithiophosphonate ligands and
two neutral monodentate N-bonded 3-acetylpyridine li-
gands in the axial positions.
Ni-S [247.36(7), 252.80(8) pm (1) and 245.94(8), 248.00(8)
pm (3)] and Ni-N bond lengths [222.7(2) (1), 216.4(2) pm
(3)] are shorter than those in 1, while the S-Ni-S [81.69(2)
(1), 83.00(2)° (3)], N-Ni-S [90.68(6) (1), 92.48(6)° (3)], and
S-P-S [109.89(4) (1), 110.34(4)° (3)] bond angles in 3 are
larger than those in 1, presumably due to the presence of
the bulkier 2,4-tBu2C6H3 group (Table 1).
In 1 and 3, the P-S bond lengths of 198.6(1)-200.1(1) are
similar to those of related complexes (Table 1) [8]. In 3, the
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Paramagnetic Octahedral p-Methoxyphenyldithiophosphonato Nickel(II) Complexes
Table 1 Selected bond lengths/pm and angles/deg for 1 and 3 and
General procedure for the preparation of 1-3:
comparison with [Ni{S2P(OMe)(p-CH3O-C6H4)-κS,SЈ}2(L-κN)2]
(L ϭ pyridine (I), 4-NH2-pyridine (II)) [8]
0.1 g of the square-planar NiII complex [Ni{S2P(OR)(p-CH3O-
C6H4)-κS,SЈ}2] was dissolved in CH2Cl2 (15 mL) and an excess of
3-acetylpyridine (1.5 mL) in EtOH (5 mL) was added. The purple
solution was refluxed until it turned green. The solvent was evapo-
rated at room temperature until 2 or 3 mL of solution remained.
Green crystals were obtained from this solution, isolated, dried in
vacuum and washed with diethyl ether.
1
3
I
II
Ni(1)-N(1)
Ni(1)-S(2)
Ni(1)-S(1)
S(1)-P(1)
S(2)-P(1)
N(1)-Ni(1)-S(2)
S(2)-Ni(1)-S(1)
S(2)-P(1)-S(1)
212.7(2)
247.36(7)
252.80(8)
199.8(1)
199.9(1)
90.68(6)
81.69(2)
109.89(4)
216.4(2)
245.94(8)
248.00(8)
200.1(1)
198.6(1)
92.48(6)
83.00(2)
110.34(4)
212.5(3)
249.4(1)
250.4(1)
198.7(1)
199.8(1)
90.90(8)
81.68(4)
110.19(6)
210.3(3)
251.6(1)
249.2(1)
200.0(1)
198.5(1)
90.76(9)
81.88(3)
110.91(5)
3.1 trans-Bis{O-ethyl(4-methoxyphenyldithiophos-
phonato)-κS,SЈ}bis(3-acetylpyridine-κN)nickel(II) (1):
[Ni{S2P(OEt)(p-CH3O-C6H4)-κS,SЈ}2] (0.1 g, 0.18 mmol). Yield:
0.13 g (82 %); mp 121 °C. C32H38N2NiO6P2S4: calcd. C 48.31, H
4.81, N 3.52, S 16.12; found C 48.2, H 4.13, N 3.45, S 16.9 %.
EI MS: 552 [M-2L]ϩ (100 %), 524 [M-2L-C2H4]ϩ (10 %), 215
[(MeOC6H4)PS2O]ϩ (19 %), 155 [(MeOC6H4)PO]ϩ (81 %), 139
[(MeOC6H4)P]ϩ (44 %), 108 [MeOC6H4]ϩ (58 %), and fragmentation prod-
ucts thereof (L ϭ 3-acetylpyridine). IR (cmϪ1): 1684vs, 1592vs, 1496s ν(CO),
1023vs ν(PO), 647s νasym(PS2), 546vs νsym(PS2). µeff ϭ 3.15 B.M.. UV-vis
spectrum: λmax ϭ 523 (ε ϭ 84) and 697 nm (ε ϭ168).
3 Experimental
Solvents were dried and distilled prior to use by standard methods.
Compounds were handled with exclusion of air and moisture. Ele-
mental analyses were determined with a VARIO EL (Heraeus).
Mass spectra were recorded with a MAT-8230 (EI-MS, 70 eV). IR
spectra were recorded as KBr disks with a Perkin-Elmer 2000 FT-
IR spectrometer in the range 400-4000 cmϪ1. The UV-vis spectra
were recorded on a LAMBDA 900 (Perkin Elmer) spectrometer.
Melting points (Gallenkamp) are uncorrected. The magnetic mo-
ments were determined with a magnetic susceptibility balance of
Johnson Mathey Alfa Products. [Ni{S2P(OR)(p-CH3O-C6H4)-
3.2 trans-Bis{O-isopropyl(4-methoxyphenyldithiophos-
phonato)-κS,SЈ}bis(3-acetylpyridine-κN)nickel(II) (2):
[Ni{S2P(OiPr)(p-CH3O-C6H4)-κS,SЈ}2] (0.1 g, 0.17 mmol). Yield:
0.11 g (79 %); mp 127 °C. C34H42N2NiO6P2S4: calcd. C 49.58, H
5.14, N 3.40, S 15.57; found C 49.5, H 5.56, N 3.51, S 15.0 %.
κS,SЈ}2] (R ϭ Et, Pr [10], 2,4-tBu2C6H3 [12]) were prepared ac-
cording to literature procedures.
i
Table 2 Crystal data and structure refinement for complexes 1 and 3
1
3
Empirical formula
C32H38N2NiO6P2S4
795.53
208(2)
monoclinic
P21/c
C56H70N2NiO6P2S4
1116.03
213(2)
monoclinic
P21/c
Formula weight
Temperature (K)
Crystal system
Space group
Unit cell dimensions
a /pm
b /pm
1095.3(2)
1278.5(2)
1116.8(2)
2256.0(4)
c /pm
1425.6(2)
111.895(2)
1.8524(5)
2
1.426
0.879
828
0.20 x 0.10 x 0.10
2.22 to 29.28
Ϫ13<ϭh<ϭ14
Ϫ16<ϭk<ϭ15
Ϫ19<ϭl<ϭ8
10041
1210.4(2)
110.133(3)
2.8631(8)
2
1.295
0.590
1180
0.20 x 0.15 x 0.10
1.81 to 29.39
Ϫ14<ϭh<ϭ10
Ϫ30<ϭk<ϭ30,
Ϫ13<ϭl<ϭ16
18046
β /°
Volume /nm3
Z
Density (calc.) /Mg/m3
Absorption coefficient/mmϪ1
F(000)
Crystal size /mm3
θ range for data collection /°
Index ranges
Reflections collected
Independent reflections
Absorption correction
Max. and min. transmission
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I>2σ(I)]
4518 [R(int) ϭ 0.0391]
SADABS
0.9172 and 0.8438
Full-matrix least-squares on F2
4518/0/290
7128 [R(int) ϭ 0.0479]
SADABS
0.9434 and 0.8912
Full-matrix least-squares on F2
7128/0/462
1.109
1.115
R1 ϭ 0.0549
wR2 ϭ 0.0912
R1 ϭ 0.0820
wR2 ϭ 0.0988
0.461 and Ϫ0.377
R1 ϭ 0.0577
wR2 ϭ 0.0978
R1 ϭ 0.0947
wR2 ϭ 0.1087
0.694 and Ϫ0.621
R indices (all data)
Ϫ3
˚
Largest diff. peak and hole /eA
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M. Karakus, P. Lönnecke, E. Hey-Hawkins
EI MS: 580 [M-2L]ϩ (65 %), 538 [M-2L-CMe2]ϩ ( 15 %), 496 [M-2L-
2CMe2]ϩ (96 %),275 [(MeOC6H4)PS2ONi]ϩ) (19 %), 187 [MeOC6H4POS]ϩ
(34 %), 155 [MeOC6H4PO]ϩ (100 %), 139 [MeOC6H4P]ϩ (22 %), 108
[MeOC6H4]ϩ (33 %), and fragmentation products thereof (L ϭ 3-acetylpyri-
dine). IR (cmϪ1): 1696vs, 1592vs, 1498s ν(CO), 1020m ν(PO)?, 959 vs ν(PO)?,
647s νasym(PS2), 546vs νsym(PS2). µeff ϭ 3.04 B.M.. UV-vis spectrum: λmax ϭ
524 (ε ϭ 70) and 689 nm (ε ϭ 87).
bridge CB2 1EZ, UK; fax: (ϩ44) 1223-336-033; or deposit@-
ccdc.cam.uk).
Acknowledgement. M. Karakus is grateful to DAAD for a postdoc-
toral fellowship (A/03/21316).
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phenyldithiophosphonato)-κS,SЈ}bis(3-acetylpyridine-
κN)nickel(II) (3):
[Ni{S2P(O-2,4-tBu2C6H3)(p-CH3O-C6H4)-κS,SЈ}2] (0.1 g, 0.11
mmol). Yield: 0.068 g (54 %); mp 120 °C. C56H70N2NiO6P2S4:
calcd. C 60.26, H 6.32, N 2.50, S 11.49, found C 59.9, H 7.57, N
2.48, S 11.5 %.
EI MS: 873 [M-2L]ϩ (28 %), 667 [M-2L-O(tBu2C6H3)]ϩ (18 %), 259
[MeOC6H4PS2Ni]ϩ (25 %), 191 [tBu2C6H3]ϩ (100 %), 139 [MeOC6H4P]ϩ
(22 %), 57 [C(CH3)3]ϩ (89 %), and fragmentation products thereof (L ϭ 3-
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3.4 X-ray crystal structure determination of 1 and 3
Crystallographic data are given in Table 2. Data [λ(MoKα) ϭ
˚
0.71073 A] were collected with a Siemens CCD (SMART) dif-
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fractometer. All observed reflections were used for determination
of the unit cell parameters. Empirical absorption correction with
SADABS [14]. The structure was solved by direct methods
(SHELXTL PLUS [15]). H atoms located by difference maps and
refined isotropically.
2002, C58, m388.
´
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CCDC-231725 (1) and -231726 (3) contain the supplementary crys-
tallographic data for this paper. These data can be obtained free of
charge via www.ccdc.cam.ac.uk/conts/retrieving.html (or from the
Cambridge Crystallographic Data Centre, 12 Union Road, Cam-
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Crystal Structure Determination, XP: Interactive Molecular
Graphics.
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