Bis(μ-6-hydroxypicolinato)-μ-oxobis[dipyridinemanganese(III)] monohydrate

Article abstract of DOI:10.1107/S0108270104012624

The title compound, [Mn₂(μ-O)(C₆ H ₃NO₃)₂(C₅H₅N) ₄]·H₂O, was isolated from the reaction of 2,6-pyridinedicarboxylic acid with [Mn₁₂O₁₂(CH ₃COO)₁₆(H₂O)₄] in pyridine. The dimanganese complex has twofold symmetry; the Mn^III atoms are bridged by one oxo and two amidate ligands and show compressed octahedral Jahn-Teller distortion. The molecular packing comprises a three-dimensional structure constructed by means of extensive intermolecular interactions, including three kinds of hydrogen bonds and π-π interactions.

Full text of DOI:10.1107/S0108270104012624

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
compound, [Mn2(ꢀ-O)(hpc)2(py)4]ÁH2O, (I), containing an
[MnI2II(ꢀ-O)]4+ core bridged by a 6-hydroxypicolinate ion
(hpc2 ).
ISSN 0108-2701
Complex (I) was obtained during the course of our attempt
to synthesize new multinuclear manganese complexes using
2,6-pyridinedicarboxylic acid (pdcH2) and [Mn12O12(CH3-
COO)16(H2O)4] (abbreviated to Mn12-ac) in pyridine (see
equation 1). In this reaction, the pdcH2 ligand could not
replace the acetate ions of Mn12-ac but was oxidized to hpc2
(see equation 2). A possible mechanism may be oxidation of
pdcH2 followed by removal of carbon dioxide.
Bis(l-6-hydroxypicolinato)-l-oxo-
bis[dipyridinemanganese(III)]
monohydrate
Guo-Qing Bian, Takayoshi Kuroda-Sowa,* Hisashi
Konaka, Masahiko Maekawa and Megumu Munakata
Department of Chemistry, Faculty of Science and Engineering, Kinki University,
Higashi-Osaka, Osaka 577, Japan
Correspondence e-mail: kuroda@chem.kindai.ac.jp
Received 6 May 2004
Accepted 24 May 2004
Online 22 June 2004
Complex (I) consists of two hpc2 ions, four pyridine rings
and two MnIII ions bridged by an oxo ion (Fig. 1 and Table 1).
Each Mn ion is coordinated by two hpc2 ions in bridging and
chelating fashions, so that the molecule has a twofold axis
perpendicular to the line connecting the two MnIII ions and
passing through the ꢀ-oxo ion. The N1/C1/O1 amidate group
of each hpc2 ion bridges the two MnIII ions, while the N1/C5/
C6/O2 carboxypyridine group chelates to an MnIII ion to form
a ®ve-membered ring. Coordination of two pyridine rings
completes a distorted octahedral six-coordination around each
Mn ion.
The title compound, [Mn2(ꢀ-O)(C6H3NO3)2(C5H5N)4]ÁH2O,
was isolated from the reaction of 2,6-pyridinedicarboxylic acid
with [Mn12O12(CH3COO)16(H2O)4] in pyridine. The diman-
ganese complex has twofold symmetry; the MnIII atoms are
bridged by one oxo and two amidate ligands and show
compressed octahedral Jahn±Teller distortion. The molecular
packing comprises a three-dimensional structure constructed
by means of extensive intermolecular interactions, including
three kinds of hydrogen bonds and ꢁ±ꢁ interactions.
The Mn ions exhibit a marked Jahn±Teller (J±T) distortion,
as expected for a high-spin d4 MnIII ion (Cotton et al., 1999).
The Mn1ÐO2 and Mn1ÐO4 bond distances [1.939 (2) and
Comment
The discovery of the role of manganese at the active sites in
various enzymatic systems has given considerable impetus to
research in the ®eld of polynuclear complexes of manganese.
The manganese catalase in Lactobacillus platarum has been
shown to contain a dimanganese unit with [MnI2II(ꢀ-oxo)(ꢀ-
carboxylato)2] cores (Fronko et al., 1988). Several Mn
complexes containing the [Mn2(ꢀ-O)]4+ core have been
Ê
1.789 (1) A, respectively] are the shortest among the six MnÐ
N and MnÐO bonds, and the other four are all longer than
Ê
2.00 A, indicating a compression type of J±T distortion.
reported so far (Sheats et al., 1987; Wieghardt et al., 1988; Wu
et al., 1990; Hotzelmann et al., 1992; Vincent et al., 1993;
Gultneh et al., 1995; Canada-Vilalta et al., 2004). The two Mn
ions in those complexes are bridged by oxo and dicarboxylate
ligands, and the six-coordination around each Mn ion is
completed by ligands such as water, CH3CN and bipyridine
(py). We report here the crystal structure of the title
Figure 1
The molecular structure of (I), with the atom-numbering scheme, showing
50% probability displacement ellipsoids. The atom labelled with an
1
asterisk (*) is at the symmetry position (1 x, y,
z).
2
m338 # 2004 International Union of Crystallography
DOI: 10.1107/S0108270104012624
Acta Cryst. (2004). C60, m338±m340

metal-organic compounds
evaporation of the solvent at room temperature. Brown block-shaped
crystals of (I) suitable for X-ray analysis were obtained after four
weeks. IR (KBr pellet, cm 1): 3198 (b), 3087 (m), 2923 (m), 1654 (m),
1632 (m), 1592 (s), 1570 (m), 1435 (m), 1396 (m), 1371 (m), 1278 (w),
1193 (w), 1015 (w), 910 (w), 785 (w), 720 (m), 699 (w), 661 (w).
Crystal data
[Mn2O(C6H3NO3)2(C5H5N)4]ÁH2O
Mo Kꢃ radiation
Cell parameters from 4653
re¯ections
Mr = 734.48
Monoclinic, C2=c
a = 13.606 (8) A
ꢄ = 3.1±27.5ꢀ
Ê
Ê
1
b = 16.379 (9) A
ꢀ = 0.88 mm
T = 150.2 K
Ê
c = 14.289 (9) A
ꢂ = 104.118 (7)ꢀ
Block, brown
0.20 Â 0.15 Â 0.15 mm
3
Ê
V = 3088 (3) A
Z = 4
Dx = 1.580 Mg m
3
Data collection
Rigaku/MSC Mercury CCD
diffractometer
! scans
Absorption correction: multi-scan
(Jacobson, 1998)
Tmin = 0.764, Tmax = 0.876
11 903 measured re¯ections
3512 independent re¯ections
3144 re¯ections with I > 2ꢅ(I)
Rint = 0.034
Figure 2
ꢄmax = 27.5ꢀ
h = 13 ! 17
The molecular packing, showing intermolecular ꢁ±ꢁ interactions (dashed
lines) and hydrogen bonds (dotted lines). [Symmetry codes: (i) x, y,
k = 18 ! 21
1
2
z + 12; (ii) x + 12,
y, z + 12; (iii) 2 x, y, 1 z.]
l = 18 ! 18
Re®nement
Re®nement on F2
R[F2 > 2ꢅ(F2)] = 0.050
wR(F2) = 0.109
S = 1.12
3144 re¯ections
260 parameters
Only coordinates of H atoms
re®ned
w = 1/[ꢅ2(F2o) + (0.0468P)2
+ 5.1887P]
Among nine complexes with a similar [Mn2(ꢀ-O)]4+ core
structure, three show compressed J±T distortion; two of them
(Wieghardt et al., 1985; Sheats et al., 1987) have tridentate
capping ligands, such as Me3TACN (Me3TACN is N,N0,N00-
trimethyl-1,4,7-triazacyclononane) or HB(pz)3 [HB(pz)3 is
hydrotris(1-pyrazolyl)borate], and the other example (Vincent
et al., 1993) has a strong coordination with an N3 ligand. In
(I), the effect of the tridentate hpc2 ion together with the
strong coordination of the ꢀ-oxo ligand probably induces the
compressed J±T distortion. The Mn1ÐN1(hpc2 ) distance
where P = (F2o + 2Fc2)/3
(Á/ꢅ)max < 0.001
3
Ê
Áꢆmax = 0.40 e A
3
Ê
0.46 e A
Áꢆmin
=
Table 1
Selected geometric parameters (A, ).
ꢀ
Ê
Mn1ÐMn1iv
Mn1ÐO1iv
Mn1ÐO2
3.172 (1)
2.083 (2)
1.939 (2)
1.789 (1)
Mn1ÐN1
Mn1ÐN2
Mn1ÐN3
2.094 (2)
2.169 (2)
2.325 (2)
Ê
[2.094 (2) A] is shorter than the Mn1ÐN2/N3(py) bonds
Ê
[2.169 (2) and 2.325 (2) A], which is also attributable to the
effect of the tridentate nature of the hpc2 ion. The
Mn1ÐO4
O1ivÐMn1ÐO2
O1ivÐMn1ÐO4
O1ivÐMn1ÐN1
O1ivÐMn1ÐN2
O1ivÐMn1ÐN3
O2ÐMn1ÐO4
O2ÐMn1ÐN1
O2ÐMn1ÐN2
90.95 (8)
96.18 (8)
93.10 (7)
90.41 (7)
173.97 (8)
172.80 (6)
80.98 (8)
89.37 (8)
O2ÐMn1ÐN3
O4ÐMn1ÐN1
O4ÐMn1ÐN2
O4ÐMn1ÐN3
N1ÐMn1ÐN2
N1ÐMn1ÐN3
N2ÐMn1ÐN3
Mn1ÐO4ÐMn1iv
84.24 (8)
97.59 (7)
91.55 (8)
88.71 (8)
169.78 (9)
89.75 (7)
85.91 (7)
125.0 (1)
Mn1Á Á ÁMn1iv [symmetry code: (iv) 1 x, y, 12 z] distance is
4+
Ê
3.172 (1) A, which is longer than the distances reported so far
Ê
(3.14±3.16 A) for complexes with the similar [Mn2(ꢀ-O)]
core structure. This difference is due to the larger MnÐOÐ
Mniv angle [125.0 (1)ꢀ] in (I).
The molecular packing is shown in Fig. 2. Water atom O5
lies on a twofold axis. Each complex molecule is connected to
neighboring molecules via ꢁ±ꢁ interactions and hydrogen
bonds (Table 2), resulting in a three-dimensional structure.
The shortest CÁ Á ÁC distance between the pyridine and hpc2
Symmetry code: (iv) 1 x; y; 12 z.
Table 2
Hydrogen-bonding geometry (A, ).
ꢀ
Ê
Ê
groups of neighboring complex molecules is 3.292 (4) A for
1
2
1
2
C4Á Á ÁC15(32 x, y
,
z), indicating a strong ꢁ±ꢁ interac-
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
tion. The dihedral angle between these two planes is
17.28 (10)ꢀ. The absence of any counter-ions in (I) enables
such intermolecular interactions.
O5ÐH14Á Á ÁO3iii
C2ÐH1Á Á ÁO2i
C7ÐH4Á Á ÁO5v
0.87 (2)
0.96 (3)
0.92 (3)
1.88 (2)
2.63 (2)
2.38 (2)
2.748 (3)
3.340 (3)
3.137 (3)
178 (1)
131 (2)
140 (2)
Symmetry codes: (i) x; y; z ‡ 12; (iii) 2 x; y; 1 z; (v) 23 x; 12 y; 1 z.
Experimental
Mn12-ac was prepared according to a literature method (Lis, 1980). To
a solution of Mn12-ac (0.05 mmol) in pyridine (10 ml) was added
pdcH2 (0.4 mmol). After stirring for 30 min, the mixture was ®ltered
and the dark-brown ®ltrate was left to stand, allowing slow
H atoms were located from difference density maps and their
2
coordinates were re®ned, with Uiso(H) = 0.0146 A . The CÐH
Ê
and OÐH bond lengths are 0.80 (3)±1.00 (3) and 0.87 (2) A,
respectively.
Ê
ꢁ
Acta Cryst. (2004). C60, m338±m340
Guo-Qing Bian et al.
[Mn2O(C6H3NO3)2(C5H5N)4]ÁH2O m339

metal-organic compounds
Hotzelmann, R., Wieghardt, K., Florke, U., Haupt, H.-J., Weatherburn, D. C.,
Bonvoisin, J., Blondin, G. & Girerd, J. J. (1992). J. Am. Chem. Soc. 114,
1681±1691.
Jacobson, R. (1998). REQAB. Iowa State University, USA.
Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National
Laboratory, Tennessee, USA.
Data collection: CrystalClear (Rigaku, 2001); cell re®nement:
CrystalClear; data reduction: TEXSAN (Molecular Structure
Corporation & Rigaku, 2000); program(s) used to solve structure:
SHELXS97 (Sheldrick, 1997); program(s) used to re®ne structure:
SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII
(Johnson, 1976) and MERCURY (Version 1.2.1; Bruno et al., 2002);
software used to prepare material for publication: TEXSAN.
Lis, T. (1980). Acta Cryst. B36, 2042±2046.
Molecular Structure Corporation & Rigaku (2000). TEXSAN. Version 1.11.
MSC, 3200 Research Forest Drive, The Woodlands, TX 77381, USA, and
Rigaku Corporation, 3-9-12 Akishima, Tokyo, Japan.
Rigaku (2001). CrystalClear. Rigaku Corporation, 3-9-12 Akishima, Tokyo,
Japan.
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Petrouleas, V., Stubbe, J., Armstrong, W. H., Beer, R. H. & Lippard, S. J.
(1987). J. Am. Chem. Soc. 109, 1435±1444.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: OB1180). Services for accessing these data are
described at the back of the journal.
Sheldrick, G. M. (1997). SHELXL97 and SHELXS97. University of
GoÈttingen, Germany.
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ꢁ
m340 Guo-Qing Bian et al.
[Mn2O(C6H3NO3)2(C5H5N)4]ÁH2O
Acta Cryst. (2004). C60, m338±m340