A carboxyl­ato-supported alkoxo-bridged dimanganese(III) complex: bis(μ-benzoato-O:O′)­bis­[3-(3-meth­oxy­salicyl­idene­amino)­propanolato-O,N,O′:O′]­di­manganese(III)

The title compound, [Mn₂(C₁₁H₁₃NO₃)₂(C₇H₅O₂)₂], is a centrosymmetric dinuclear manganese(III) complex in which the two Mn atoms are bridged by two alkoxo groups and supported by two carboxyl­ate groups, with an Mn...Mn distance of 2.8720 (15) Å.

S1. Comment

Dinuclear manganese(III) complexes are of current interest because they can mimic the active sites of manganese-containing enzymes (Limburg et al., 1999). Recently, it has been postulated that photosystem-II has two oxo-bridged dimanganese dimers that are connected by two carboxylate groups (Tommos & Babcock, 1998; Hoganson & Babcock, 1997). In manganese catalase (Halm & Bender, 1988) and manganese peroxidase (Wariishi et al., 1988), the dimanganese sites are also found to be bridged by oxo groups. Because of the lack of suitable crystals, the detailed structural information of some enzymes is still limited. Therefore it is important to synthesize di- or polymeric manganese complexes. In this paper, we report a dimanganese(III) complex with an Mn···Mn distance of 2.8720 (15) Å. \sch

The title complex, (I), is a discrete dinuclear manganese compound (Fig. 1). The two Mn atoms are related by a crystallographic inversion center. The coordination geometry around each Mn atom is an elongated octahedron. The imino N, phenolic O and the two bridging alkoxo O atoms form the equatorial plane around the Mn atom. The in-plane distances for Mn—N1 [2.000 (3) Å], Mn—O3 [1.896 (2) Å], Mn—O4 [1.859 (2) Å] and Mn—O3ⁱ [1.939 (2) Å] are comparable to those in other Mn^III complexes, e.g., [Mn(salpn)(EtOH)₂] [H₂salpn = N,N'-bis(salicylidene)-1,3-diaminopropane] [Mn—N 2.017 (2) Å and 2.028 (2) Å, Mn—O 1.874 (2) Å and 1.891 (2) Å] (Gohdes & Armstrong, 1992) and [Mn(salpa)(MeOH)Cl]₂ (H₂salpa = 3-salicylidene-amino-1-propanol) [Mn—N 1.995 (4) Å, Mn—O 1.853 (3) Å and Mn—O 1.926 (3) Å] (Larson et al., 1992). Two carboxylato O atoms coordinate to the Mn atom via the elongated axial direction with Mn—O1 and Mn—O2 bond distances of 2.262 (3) and 2.216 (3) Å. These bonds are considerably longer than those found in the equatorial plane, which could be due in part both to the Jahn-Teller distortion and to the different type of ligands and their mode of coordination. The Mn₂O₂ core is exactly planar by symmetry. The Mn···Mn distance of 2.8720 (15) Å is similar to those found in [Mn(salpa)(acetato)]₂ (2.869 (1) Å) (Mikuriya et al., 1981) and [Mn(salpa)(benzoato)]₂ (2.855 (2) Å) (Zhang, Zhou et al., 1999a), but somewhat shorter than those found in [Mn(salpa)(MeOH)Cl]₂ [3.011 (1) Å] (Larson et al., 1992) and [Mn(salpa)(H₂O)Cl]₂ [3.001 (1) Å] (Zhang, Sun et al., 1999). This indicates that the effect of two bridging carboxylato groups instead of four individual axial monodentate ligands, such as chloride, water or methanol, on the Mn₂O₂ core is to lead to a marked decrease in the manganese-manganese separation. Consequently, the angle O3—Mn—O3ⁱ is expanded to 83.1 (1)°. This angle is similar to that found in [Mn(salpa)(acetato)]₂ [83.66 (7)°] but larger than that in [Mn(salpa)(MeOH)Cl]₂ [78.2 (1)°]. Concerning the intermolecular packing between the dimers there are no π-stacking interactions as might have been expected (Janiak, 2000). Some tilted C—H···π interactions exist between the benzoate ring and the aromatic moiety of the salicylidene ligand (Janiak et al., 2000). The shortest intermolecular ring-centroid···ring-centroid (Cg) contacts (with interplanar angle) are Cg1···Cg2ⁱⁱ 4.71 Å (54.7°) and Cg2···Cg1ⁱⁱⁱ 4.59 Å (54.7°). Cg1 is the phenyl ring from C2 to C7, Cg2 is the salicyl ring from C12 to C17 [symmetry codes (ii) 1/2 - x, -1/2 + y, 1/2 - z; (iii) -1/2 + x, 1/2 - y, 1/2 + z). The shortest intermolecular aromatic C—H···ring-centroid contacts are C6—H6a···Cg2^iv 2.90 Å and C16—H16A···Cg1^v 3.27 Å [symmetry codes (iv) 1/2 + x, 1/2 - y, 1/2 + z; (v) 1/2 - x, 1/2 + y, 1/2 - z) [calculated with the program PLATON (Spek, 1998)].

Related literature

For related literature, see: Gohdes & Armstrong (1992); Halm & Bender (1988); Hoganson & Babcock (1997); Janiak (2000); Janiak, Temizdemir, Dechert, Deck, Girgsdies, Heinze, Kolm, Scharmann & Zipffel (2000); Larson et al. (1992); Limburg et al. (1999); Mikuriya et al. (1981); Spek (1998); Tommos & Babcock (1998); Wariishi et al. (1988); Zhang, Sun, Kong & Zhao (1999); Zhang, Zhou, Meng, Xu & Xu (1999).

S2. Experimental

Compound (I) was synthesized by the reaction of the ligand H₂vanpa with manganese benzoate in the molar ratio of 1:1 in ethanol. To an ethanolic solution (20 ml) of 3-methoxysalicylaldehyde (1.52 g, 10 mmol) was added 3-amino-1-propanol (0.75 g, 10 mmol) with stirring for 30 min at 323 K. The solution turned yellow. To this solution was added manganese benzoate dihydrate (3.0 g, 10 mmol). The colour turned green quickly. The resulting solution was then put aside for several days. Crystals were obtained by slow evaporation of the solvent at room temperature (yield: 3.1 g. 82%). Crystal analysis, IR (KBr pellet): 3050 (w), 3000 (w), 2900 (m), 2850 (w), 1615 (s), 1588 (s), 1545 (s), 1460 (s), 1440 (s), 1375 (s), 1375 (s), 1315 (s), 1250 (s), 1220 (s), 1165 (w), 1080 (s), 1060 (s), 950 (m), 870 (m), 735 (s), 670 (m), 630 (s), 610 (s), 485 (w).

S3. Refinement

H atoms were treated using appropriate riding models (AFIX = m3) (C—H 0.93 and 0.97 Å). U(H) = 1.2 U(C), except for the hydrogen atoms of the methyl group (C18) for which U(H) = 1.5 U(C).

Computing details

Data collection: SMART (Bruker 1997); cell refinement: SMART; data reduction: SAINT (Bruker 1997); program(s) used to solve structure: SHELXTL (Sheldrick, 1998); program(s) used to refine structure: SHELXTL; molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. ORTEP-3 (Farrugia, 1997) view of compound (I) showing the labelling of the non-hydrogen atoms [symmetry code (i) 1 - x, -y, 1 - z]. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as spheres of arbitrary radii.

bis(µ-benzoato-O:O')-bis(2-(6-methoxy)salicylideneamino -3-propanolato-N,O'',O''':O''')-dimanganese(III)

Crystal data

[Mn2(C11H13NO3)2(C7H5O2)2]	Refining the unit cell using all collected reflections, the theta_max and theta_min must be the same as reflns_theta_min and reflns_theta_max.
Mr = 766.55	Dx = 1.505 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 13.009 (3) Å	Cell parameters from 2959 reflections
b = 9.333 (5) Å	θ = 1.8–25.0°
c = 15.162 (5) Å	µ = 0.81 mm^−1
β = 113.24 (2)°	T = 293 K
V = 1691.5 (11) Å^3	Plate, brown
Z = 2	0.50 × 0.20 × 0.18 mm
F(000) = 792

Data collection

Siemens smart CCD diffractometer	2959 independent reflections
Radiation source: fine-focus sealed tube	2088 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
ω scans	θmax = 25.0°, θmin = 1.8°
Absorption correction: empirical (using intensity measurements) (SADABS; Blessing, 1995)	h = −9→15
Tmin = 0.737, Tmax = 1.000	k = −11→6
6242 measured reflections	l = −18→14

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.047	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.116	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0404P)^2 + 0.980P] where P = (Fo^2 + 2Fc^2)/3
2954 reflections	(Δ/σ)max = −0.002
226 parameters	Δρmax = 0.28 e Å^−3
0 restraints	Δρmin = −0.34 e Å^−3

Special details

Experimental. An empirical absorption correction on the basis of symmetry-equivalent reflections has been performed with the program SADABS.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Mn	0.44908 (4)	0.12977 (6)	0.51402 (4)	0.0360 (2)
O1	0.4827 (2)	0.1992 (3)	0.3849 (2)	0.0482 (7)
O2	0.5678 (2)	−0.0046 (3)	0.3682 (2)	0.0477 (7)
O3	0.5945 (2)	0.0496 (3)	0.5553 (2)	0.0398 (6)
O4	0.3024 (2)	0.1960 (3)	0.4637 (2)	0.0445 (6)
O5	0.0855 (2)	0.2270 (3)	0.3731 (2)	0.0491 (7)
N1	0.5061 (2)	0.3110 (3)	0.5875 (2)	0.0391 (7)
C1	0.5352 (3)	0.1240 (4)	0.3475 (3)	0.0422 (9)
C2	0.5630 (3)	0.1921 (4)	0.2696 (2)	0.0418 (9)
C3	0.4988 (3)	0.3066 (4)	0.2173 (3)	0.0513 (10)
H3A	0.4399 (3)	0.3408 (4)	0.2314 (3)	0.062*
C4	0.5217 (4)	0.3694 (5)	0.1449 (3)	0.0644 (12)
H4A	0.4770 (4)	0.4438 (5)	0.1091 (3)	0.077*
C5	0.6108 (5)	0.3218 (5)	0.1259 (3)	0.0708 (14)
H5A	0.6278 (5)	0.3658 (5)	0.0783 (3)	0.085*
C6	0.6749 (4)	0.2092 (5)	0.1770 (3)	0.0644 (13)
H6A	0.7349 (4)	0.1774 (5)	0.1637 (3)	0.077*
C7	0.6505 (3)	0.1428 (4)	0.2484 (3)	0.0497 (10)
H7A	0.6931 (3)	0.0653 (4)	0.2818 (3)	0.060*
C8	0.6949 (3)	0.0808 (5)	0.6332 (3)	0.0667 (13)
H8A	0.7494 (3)	0.1149 (5)	0.6091 (3)	0.080*
H8B	0.7240 (3)	−0.0062 (5)	0.6693 (3)	0.080*
C9	0.6800 (4)	0.1910 (5)	0.6982 (3)	0.0617 (12)
H9A	0.6343 (4)	0.1506 (5)	0.7294 (3)	0.074*
H9B	0.7526 (4)	0.2132 (5)	0.7478 (3)	0.074*
C10	0.6273 (3)	0.3264 (5)	0.6495 (3)	0.0596 (12)
H10A	0.6663 (3)	0.3595 (5)	0.6104 (3)	0.072*
H10B	0.6361 (3)	0.3989 (5)	0.6978 (3)	0.072*
C11	0.4435 (3)	0.4191 (4)	0.5822 (3)	0.0445 (10)
H11A	0.4795 (3)	0.4996 (4)	0.6168 (3)	0.053*
C12	0.3251 (3)	0.4322 (4)	0.5301 (3)	0.0404 (9)
C13	0.2602 (3)	0.3199 (4)	0.4736 (2)	0.0374 (9)
C14	0.1435 (3)	0.3414 (4)	0.4256 (3)	0.0405 (9)
C15	0.0955 (3)	0.4683 (4)	0.4344 (3)	0.0519 (11)
H15A	0.0187 (3)	0.4812 (4)	0.4025 (3)	0.062*
C16	0.1609 (4)	0.5775 (5)	0.4908 (3)	0.0622 (12)
H16A	0.1275 (4)	0.6632 (5)	0.4965 (3)	0.075*
C17	0.2731 (4)	0.5607 (4)	0.5377 (3)	0.0562 (11)
H17A	0.3159 (4)	0.6349 (4)	0.5754 (3)	0.067*
C18	−0.0315 (3)	0.2451 (5)	0.3192 (3)	0.0608 (12)
H18A	−0.0625 (3)	0.1578 (5)	0.2857 (3)	0.091*
H18B	−0.0434 (3)	0.3212 (5)	0.2736 (3)	0.091*
H18C	−0.0674 (3)	0.2684 (5)	0.3618 (3)	0.091*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mn	0.0289 (3)	0.0351 (3)	0.0373 (3)	0.0020 (3)	0.0058 (2)	−0.0051 (3)
O1	0.057 (2)	0.046 (2)	0.047 (2)	0.0071 (14)	0.0257 (14)	−0.0003 (13)
O2	0.054 (2)	0.043 (2)	0.049 (2)	0.0039 (13)	0.0237 (13)	0.0005 (13)
O3	0.0275 (14)	0.0418 (15)	0.0383 (14)	0.0016 (11)	0.0003 (11)	−0.0082 (12)
O4	0.0317 (14)	0.0375 (15)	0.054 (2)	0.0067 (12)	0.0054 (12)	−0.0080 (13)
O5	0.0316 (14)	0.051 (2)	0.053 (2)	0.0071 (13)	0.0046 (12)	0.0007 (14)
N1	0.038 (2)	0.038 (2)	0.037 (2)	−0.0010 (15)	0.0107 (14)	−0.0047 (14)
C1	0.042 (2)	0.043 (2)	0.037 (2)	−0.001 (2)	0.011 (2)	−0.003 (2)
C2	0.041 (2)	0.047 (2)	0.033 (2)	−0.010 (2)	0.009 (2)	−0.011 (2)
C3	0.053 (3)	0.048 (3)	0.047 (2)	−0.002 (2)	0.014 (2)	−0.005 (2)
C4	0.086 (4)	0.048 (3)	0.053 (3)	−0.010 (3)	0.021 (3)	0.001 (2)
C5	0.094 (4)	0.070 (3)	0.050 (3)	−0.025 (3)	0.029 (3)	−0.001 (3)
C6	0.057 (3)	0.084 (4)	0.058 (3)	−0.019 (3)	0.028 (2)	−0.018 (3)
C7	0.046 (2)	0.056 (3)	0.047 (2)	−0.004 (2)	0.017 (2)	−0.006 (2)
C8	0.040 (2)	0.067 (3)	0.065 (3)	0.004 (2)	−0.009 (2)	−0.028 (2)
C9	0.047 (3)	0.067 (3)	0.050 (3)	0.004 (2)	−0.003 (2)	−0.017 (2)
C10	0.041 (2)	0.053 (3)	0.069 (3)	−0.010 (2)	0.006 (2)	−0.019 (2)
C11	0.055 (3)	0.034 (2)	0.042 (2)	−0.005 (2)	0.015 (2)	−0.008 (2)
C12	0.044 (2)	0.036 (2)	0.037 (2)	0.004 (2)	0.011 (2)	−0.002 (2)
C13	0.040 (2)	0.039 (2)	0.035 (2)	0.009 (2)	0.017 (2)	0.006 (2)
C14	0.038 (2)	0.043 (2)	0.039 (2)	0.006 (2)	0.014 (2)	0.004 (2)
C15	0.043 (2)	0.055 (3)	0.050 (3)	0.016 (2)	0.010 (2)	0.005 (2)
C16	0.067 (3)	0.046 (3)	0.066 (3)	0.029 (2)	0.018 (3)	0.002 (2)
C17	0.063 (3)	0.038 (2)	0.058 (3)	0.010 (2)	0.014 (2)	−0.006 (2)
C18	0.034 (2)	0.075 (3)	0.061 (3)	0.002 (2)	0.006 (2)	0.001 (2)

Geometric parameters (Å, º)

Mn—O4	1.859 (2)	C1—C2	1.506 (5)
Mn—O3	1.896 (2)	C2—C7	1.379 (5)
Mn—O3^i	1.939 (2)	C2—C3	1.395 (5)
Mn—N1	2.000 (3)	C3—C4	1.376 (5)
Mn—O2^i	2.216 (3)	C4—C5	1.375 (6)
Mn—O1	2.262 (3)	C5—C6	1.375 (6)
O1—C1	1.260 (4)	C6—C7	1.388 (5)
O2—C1	1.270 (4)	C8—C9	1.489 (5)
O2—Mn^i	2.216 (3)	C9—C10	1.488 (6)
O3—C8	1.403 (4)	C11—C12	1.432 (5)
O3—Mn^i	1.939 (2)	C12—C17	1.404 (5)
O4—C13	1.314 (4)	C12—C13	1.405 (5)
O5—C14	1.367 (4)	C13—C14	1.416 (5)
O5—C18	1.425 (4)	C14—C15	1.370 (5)
N1—C11	1.279 (4)	C15—C16	1.385 (6)
N1—C10	1.490 (5)	C16—C17	1.357 (6)
O4—Mn—O3	174.46 (10)	C11—N1—Mn	123.0 (3)
O4—Mn—O3^i	91.80 (10)	C10—N1—Mn	120.0 (2)
O3—Mn—O3^i	83.00 (10)	O1—C1—O2	127.0 (3)
O4—Mn—N1	92.44 (11)	O1—C1—C2	117.3 (3)
O3—Mn—N1	92.72 (11)	O2—C1—C2	115.7 (3)
O3^i—Mn—N1	175.63 (11)	C7—C2—C3	119.2 (4)
O4—Mn—O2^i	95.42 (11)	C7—C2—C1	121.2 (4)
O3—Mn—O2^i	85.91 (10)	C3—C2—C1	119.6 (3)
O3^i—Mn—O2^i	83.16 (10)	C4—C3—C2	120.7 (4)
N1—Mn—O2^i	97.47 (11)	C3—C4—C5	119.7 (4)
O4—Mn—O1	93.84 (11)	C6—C5—C4	120.2 (4)
O3—Mn—O1	83.72 (10)	C5—C6—C7	120.5 (4)
O3^i—Mn—O1	83.85 (10)	C2—C7—C6	119.7 (4)
N1—Mn—O1	94.83 (11)	O3—C8—C9	112.3 (3)
O2^i—Mn—O1	164.26 (9)	C10—C9—C8	114.4 (4)
O4—Mn—Mn^i	132.70 (8)	C9—C10—N1	113.4 (3)
O3—Mn—Mn^i	42.07 (7)	N1—C11—C12	128.4 (3)
O3^i—Mn—Mn^i	40.93 (7)	C17—C12—C13	119.6 (4)
N1—Mn—Mn^i	134.79 (9)	C17—C12—C11	118.4 (4)
O2^i—Mn—Mn^i	82.68 (7)	C13—C12—C11	122.0 (3)
O1—Mn—Mn^i	81.68 (7)	O4—C13—C12	123.3 (3)
C1—O1—Mn	123.7 (2)	O4—C13—C14	118.5 (3)
C1—O2—Mn^i	124.6 (2)	C12—C13—C14	118.2 (3)
C8—O3—Mn	132.3 (2)	O5—C14—C15	124.4 (4)
C8—O3—Mn^i	127.7 (2)	O5—C14—C13	115.0 (3)
Mn—O3—Mn^i	96.99 (10)	C15—C14—C13	120.6 (4)
C13—O4—Mn	130.8 (2)	C14—C15—C16	120.3 (4)
C14—O5—C18	117.4 (3)	C17—C16—C15	120.7 (4)
C11—N1—C10	116.9 (3)	C16—C17—C12	120.6 (4)

Symmetry code: (i) −x+1, −y, −z+1.