ISSN 10637745, Crystallography Reports, 2009, Vol. 54, No. 7, pp. 1135–1138. © Pleiades Publishing, Inc., 2009.
1135 INTRODUCTION
Investigations into the magnetic properties of mol eculebased materials containing a polymetallic assembly have become a fascinating subject in the field of condensed matter physics and materials chemistry [1, 2]. Much attention has been focused on coordina tion complexes with novel magnetic properties, which may have potentially useful applications in materials science [3]. The prime strategy for designing these molecular materials is to use a suitable bridging ligand that determines the nature of the magnetic interac tions [4].
Transition metal compounds containing Schiff base ligands have been of great interest for many years [5]. Several examples of trihomo and heteronuclear complexes derived from the Schiff base ligands have been reported [6–8]. Some binuclear Co(salen), where Salen is bis(salicylidene)1,2ethylendiamine, complexes have been synthesized [9–11], but in these complexes two Co atoms bridging by two oxygen atoms. However, binuclear Schiff base complexes with a few carbons in bridge have not been seen. As an extension of the work on the structural characteriza tion of binuclear Schiff base compounds, here, we STRUCTURE OF ORGANIC
COMPOUNDS
Synthesis and Xray Structure Analysis of a New Binuclear Schiff Base Co(II) Complex with the Ligand
N,N'bis(3methoxysalicylidene)1,4butanediamine*
M. NasrEsfahani
Department of Materials Science & Engineering, Islamic Azad University, Najafabad Branch, Najafabad, 157, Iran email: [email protected]
Received April 20, 2009
Abstract—The title binuclear complex, tris[N,Nbis(3methoxysalicylidene)1,4diaminobutane] dico balt(II), C60H70Co2N6O15, was prepared by the reaction of the tetradentate Schiff base ligand bis(3methox ysalicylidene)1,4diaminobutane and Co(CH3COO)2⋅ 4H2O in a ethanol solution and structurally charac terized by singlecrystal Xray diffraction. This complex has a dinuclear structure where two Co(II) ions are bridged by one N°,N'bis(3methoxysalicylidene)1,4diaminobutane. The two Co(II) ions, have two dis torted octahedral coordination involving two O and two N atoms.
PACS numbers: 61.10.Nz; 61.66.Hg DOI: 10.1134/S1063774509070049
*The article is published in the original.
OMe
O
O
O Co
N
N
N
MeO
O O
N
O N N
Co
N O OMe
=
Fig. 1. Chemical structure of tris[N,N'bis(3methoxysalicylidene)1,4diaminobutane] dicobalt(II).
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CRYSTALLOGRAPHY REPORTS Vol. 54 No. 7 2009 NASRESFAHANI
report the synthesis and Xray crystal structure of title binuclear cobalt(II) compound (Fig. 1).
EXPERIMENTAL
Tris[N,N'bis(3methoxysalicylidene)1,4diami nobutane] dicobalt(II). It was prepared by the reaction of Co(CH3COO)2 ⋅ 4H2O with MeOSalbu (molar ratio 2:3) in an ethanol solution at 298 K. To a solution (20 ml) of MeOSalbu (0.75 mmol) in ethanol was added a solution (20 ml) of Co(CH3COO)2 ⋅ 4H2O (0.5 mmol) in ethanol. The mixture was stirred at room temperature in air for four hours, whereupon it was filtered. After keeping the resulting solution at room temperature for 15 days, darkred crystals, suit able for Xray diffraction, were obtained from the mother solution at the bottom of the vessel on slow evaporation of the solvent. Yield is 58.5%. M.P.
(Decomposition point) 251–252°C.
Crystal structure determination. The threedimen sional intensity data were collected on an Nonius KappaCCD diffractometer. The ϕ/ωscans mode was employed for the entire data collection. Two standard
reflections were monitored every 126 reflections to check for crystal deterioration, if any, during beam exposure to the sample. The unit cell parameters were determined using SMART [12] and refined based on the positions of all strong reflections using SAINT [12]. Absorption correction was by SADABS [13]
based on symmetryequivalent and repeated reflec tions.
The structure was solved by direct methods using SIR97 [14] and refined by full matrix leastsquares on F2 using SHELXTL [15]. The crystallographic data are listed in Table 1. The data have been deposited with the Cambridge Crystallographic Database, CCDC no. 622950.
RESULTS AND DISCUSSION
Selected bond distances and bond angles for non hydrogen atoms are given in Table 2. A general view of the molecule indicating the atomic numbering scheme (a thermal ellipsoid drawn at 30% probability) is shown in Fig. 2.
Table 1. Crystal data and structure refinement for the title compound
Chemical Formula C60H70Co2N6O15
Molecular weight 1233.08
System, sp. gr., Z Triclinic, P , 2
a, Å 13.246(2)
b, Å 14.5362(17)
c, Å 15.835(5)
V, Å3 2931.8(12)
Dx, g/cm3 1.397
Radiation, λ, Å MoKα
μ, mm–1 0.638
T, K 150(2)
Sample size, mm 0.34 × 0.22 × 0.15
θmax, deg 27.5
Collection range –15 ≤ h ≤ 15, –17 ≤ k ≤ 17, –18 ≤ l ≤ 18 Number of reflections:
Measured/unique (N1), Rint/with I > 1.96σ(I) (N2)
41 005/10273, 0.0760/6835
Refinement method Fullmatrix leastsquares on F2 Number of refined parame
ters
335 Reliability factors:
wR2 relative to N1 0.1363 R1 relative to N2 0.0564
S 1.032
Δρmax/Δρmin, electron/Å3 0.68/−0.33 1
Table 2. Selected bond distances d (Å) and bond angles ω (deg)
Bond d Bond d
Co1–O2 1.927(3) Co1–O3 1.915(3) Co1–O10 1.883(3) Co1–N1 1.949(3) Co1–N2 1.935(3) Co1–N5 1.974(3) Co2–O6 1.906(3) Co2–O7 1.910(3) Co2–O11 1.887(3) Co2–N3 1.955(3) Co2–N4 1.956(3) Co2–N6 1.980(3)
Angle ω Angle ω
O2–Co1–O3 85.48(12) O2–Co1–O10 88.17(12) O2–Co1–N1 91.75(13) O2–Co1–N2 178.21(13) O2–Co1–N5 88.62(13) O3–Co1–O10 171.30(12) O3–Co1–N1 88.96(13) O3–Co1–N2 93.21(13) O3–Co1–N5 93.03(13) O10–Co1–N1 85.30(13) O10–Co1–N2 93.26(14) O10–Co1–N5 92.74(13) N1–Co1–N2 89.43(14) N1–Co1–N5 178.00(15) N2–Co1–N5 90.25(14) O6–Co2–O7 85.62(12) O6–Co2–O11 173.36(12) O6–Co2–N3 93.24(13) O6–Co2–N4 90.46(13) O6–Co2–N6 91.09(13) O7–Co2–O11 89.25(12) O7–Co2–N3 178.82(13) O7–Co2–N4 91.55(13) O7–Co2–N6 84.82(13) O11–Co2–N3 91.91(13) O11–Co2–N4 85.47(12) O11–Co2–N6 92.64(13) N3–Co2–N4 88.73(14) N3–Co2–N6 94.93(14) N4–Co2–N6 175.93(14)
CRYSTALLOGRAPHY REPORTS Vol. 54 No. 7 2009
SYNTHESIS AND XRAY STRUCTURE ANALYSIS 1137
This complex is a carbonbridged binuclear dis crete molecule (Fig. 1). The coordination geometry around each cobalt center is that of a octahedral. The Co atoms are in two octahedral environment com posed of three nitrogen and oxygen atoms of three Schiff base and have parallel meridional isomerism.
The intramolecular Co1…Co2 separation is 8.743 Å.
As shown in Table 2, it is interesting to know that the bond lengths Co1–N5 (1.974(3) Å) and Co2–N6 (1.980(3) Å) of bridged ligand have largest bond length in comparison with other bond lengths in two octahe dradrals. The stereo effect of the 4carbons chain of 1,4diaminobutane causes the Nimine atoms can not to get closer to metal centers. In contract bond lengths of Co1–O10 (1.883(3) Å) and Co2–O11 (1.887(3) Å)
are approximately similar and shorter than other Co–
O distances.
The probable reason for this difference is lack of any stereo effect in closing of O phenolate atoms to Co centers.
In general the coordination geometry around the central Co ion displays only slight distortions. The bond distances Co–O and Co–N are similar and range from 1.883(3) to 1.980(3) Å. The greatest devia tions of the bond angles from those expected for an ideal geometry are 85.48(12)° for O2–Co1–O3, 171.30(12)° for O3–Co1–O10, 85.62(12)° for O6–
Co2–O7 and 173.36(12)° for O6–Co2–O11. The remaining bond angles around Co1 and Co2 are
C10 C9
C12 C11
C8 N1 Co1
N2 C13
C14 C15
C16
C17
C20 C18
C19 O4 O3
C41 O9
C6
C7 O10 O2
N5 O15
C48 C2
C47 C46 C43 C42
C44 C45
C5 C4
C3 O1
C1 O13
O21 O5 C24 C25
C50 C49 C51
C52 C28
C26
C23 C22 O6
O14 O16
C40 O8 O7 C27 Co2
N6 C53
C54 C55
C59 C56
C57 C58
C60 O12 C29 C30
N3 O11 C31 C32
N4 C33
C34 C39 C35
C38
C37 C36
Fig. 2. ORTEP structure of the title compound with atom labeling, the ellipsoids enclose 30% of the electronic density.
Table 3. Hydrogen bonds [Å and °]
D–H⋅⋅⋅A D–H H⋅⋅⋅A D⋅⋅⋅A D–H⋅⋅⋅A
O(15)–H(15B)⋅⋅⋅O(4) 0.913(19) 1.99(2) 2.899(5) 172(5)
O(15)–H(15B)⋅⋅⋅O(3) 0.913(19) 2.49(5) 3.006(4) 116(4)
O(15)–H(15C)⋅⋅⋅O(2) 0.917(19) 1.89(2) 2.801(5) 174(5)
O(16)–H(16B)⋅⋅⋅O(7) 0.912(19) 1.93(3) 2.825(4) 166(5)
O(16)–H(16C)⋅⋅⋅O(5) 0.93(2) 2.04(2) 2.957(5) 168(5)
O(16)–H(16C)⋅⋅⋅O(6) 0.93(2) 2.53(5) 3.127(5) 123(4)
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CRYSTALLOGRAPHY REPORTS Vol. 54 No. 7 2009 NASRESFAHANI
approximately close to ideal values for octahedral geometry.
ACKNOWLEDGMENTS
The authors wish to thank the Center of Excellency (Chemistry), University of Isfahan for financially sup porting this work and Islamic Azad University, Najafa bad Branch for their partial support.
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