Structure of a dinuclear cadmium complex with 2,2′-bi­pyridine, monodentate nitrate and 3-carb­oxy-6-methyl­pyridine-2-carboxyl­ate ligands: intra­molecular carbon­yl(lone pair)⋯π(ring) and nitrate(π)⋯π(ring) inter­actions

Granifo, J.; Suarez, S.; Baggio, R.

doi:10.1107/S2056989015012384

research communications

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ISSN: 2056-9890

Volume 71| Part 8| August 2015| Pages 890-894

https://doi.org/10.1107/S2056989015012384

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Structure of a dinuclear cadmium complex with 2,2′-bipyridine, monodentate nitrate and 3-carboxy-6-methylpyridine-2-carboxylate ligands: intramolecular carbonyl(lone pair)⋯π(ring) and nitrate(π)⋯π(ring) interactions

Juan Granifo,^a ^* Sebastián Suarez ^b and Ricardo Baggio ^c ^*

^aDepartamento de Ciencias Químicas y Recursos Naturales, Facultad de Ingeniería y Ciencias, Universidad de La Frontera, Casilla 54-D, Temuco, Chile, ^bDepartamento de Química Inorgánica, Analítica y Química Física, INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina, and ^cGerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina
^*Correspondence e-mail: juan.granifo@ufrontera.cl, baggio@cnea.gov.ar

Edited by J. Simpson, University of Otago, New Zealand (Received 23 June 2015; accepted 27 June 2015; online 8 July 2015)

The centrosymmetric dinuclear complex bis(μ-3-carboxy-6-methylpyridine-2-carboxylato)-κ³N,O²:O²;κ³O²:N,O²-bis[(2,2′-bipyridine-κ²N,N′)(nitrato-κO)cadmium] methanol monosolvate, [Cd₂(C₈H₆NO₄)₂(NO₃)₂(C₁₀H₈N₂)₂]·CH₃OH, was isolated as colourless crystals from the reaction of Cd(NO₃)₂·4H₂O, 6-methylpyridine-2,3-dicarboxylic acid (mepydcH₂) and 2,2′-bipyridine in methanol. The asymmetric unit consists of a Cd^II cation bound to a μ-κ³N,O²:O²-mepydcH⁻ anion, an N,N′-bidentate 2,2′-bipyridine group and an O-monodentate nitrate anion, and is completed with a methanol solvent molecule at half-occupancy. The Cd complex unit is linked to its centrosymmetric image through a bridging mepydcH⁻ carboxylate O atom to complete the dinuclear complex molecule. Despite a significant variation in the coordination angles, indicating a considerable departure from octahedral coordination geometry about the Cd^II atom, the Cd—O and Cd—N distances in this complex are surprisingly similar. The crystal structure consists of O—H⋯O hydrogen-bonded chains parallel to a, further bound by C—H⋯O contacts along b to form planar two-dimensional arrays parallel to (001). The juxtaposed planes form interstitial columnar voids that are filled by the methanol solvent molecules. These in turn interact with the complex molecules to further stabilize the structure. A search in the literature showed that complexes with the mepydcH⁻ ligand are rare and complexes reported previously with this ligand do not adopt the μ-κ³ coordination mode found in the title compound.

Keywords: crystal structure; dinuclear Cd complex; intramolecular C—O⋯π(ring) and N—O⋯π(ring) interactions.

CCDC reference: 1409269

1. Chemical context

Pyridinedicarboxylate ligands derived from pyridine-2,3-dicarboxylic acid (pydcH₂) have been extensively used in the construction of a large variety of structural motifs. The two deprotonated forms pydcH⁻ and pydc²⁻ have been shown to adopt a wide range of coordination modes through their carboxylate oxygen and pyridyl nitrogen atoms (Wang et al., 2009 ). A search in the CSD (Version 5.3; Groom & Allen, 2014 ) disclosed ca 200 complexes displaying diverse topologies, viz. monomers (Gao et al., 2010 ; Drew et al., 1971 ), dimers (Shankar et al., 2013 ), oligomers (Yu et al., 2003 ) as well as one-dimensional (Semerci et al., 2014 ), two-dimensional (Çolak et al., 2011 ) and three-dimensional (Kanoo et al., 2012 ) polymers. In the vast majority of cases the ligand adopts an N,O-chelating mode, although there are a few exceptions to this where the binding sites attach to different metal atoms (e.g. Wang et al., 2014 ). By contrast, when complexes containing similar ligands but with methyl substituents in the 6-position were sought, namely those generated from 6-methylpyridine-2,3-dicarboxylic acid (mepydcH₂), only a single structure was found involving the monoanionic mepydcH⁻ ligand similar to that reported here (Gurunatha & Maji, 2009 ). This unique structural motif appears in the form of three isostructural, monomeric M^II (M = Fe, Co, Ni) complexes [M(bpee)₂(mepydcH)₂] (bpee = 1,2-bis(4-pyridyl)ethylene) with octahedral geometry around M^II. Both mepydcH⁻ fragments act in a simple κ²N,O²-chelating mode binding to a single nucleus while the two N-bound bpee ligands are trans-monodentate. The formation of these mononuclear complexes is unusual considering the obvious bridging potential of the bpee ligands. Mixed-ligand complexes based on non-methylated 2,3-pyridinedicarboxylate and 4,4′-bipyridine-like ligands usually generate stable polymeric structures with the exo-bidentate ligands adopting a bridging role (Kanoo et al., 2012; Wang et al., 2009; Maji et al., 2005 ).

In an attempt to understand the coordination behaviour of this unusual monoanionic mepydcH⁻ ligand better, we report the structure of the dinuclear complex [Cd₂(2,2′-bipyridine)₂(mepydcH)₂(NO₃)₂]·MeOH (I). The uncommon bridging-chelating μ₂-(κ³N,O²:O²) coordination behaviour and the fact that the ligand is only singly deprotonated has no counterpart in complexes of the non-methylated ligands and makes this a genuinely novel structure. The closest relatives with 2,2′-bipyridine as the auxiliary ligand are found with di-anionic pydc²⁻ ligands, but these are either mononuclear (Wang & Okabe, 2005 ) or form coordination polymers (Li et al., 2013 ; Yin & Liu, 2009 ; Zhang et al. 2013 ).

2. Structural commentary

The complex consists of a Cd^II cation to which a singly protonated 3-carboxy-6-methylpyridine-2-carboxylate ion (mepydcH⁻) chelates through the pyridine N and carboxylate O atoms. A chelating 2,2′-bipyridine that binds through both nitrogen atoms and a unidentate nitrate anion complete the coordination sphere; the asymmetric unit also contains a non-coordinating half-occupancy methanol solvate. This five coordinate Cd^II unit, in turn, binds to its centrosymmetric image through the carboxylate oxygen atom of the mepydcH⁻ ligand, forming a pair of Cd–O–Cd bridges. As a result, a dimeric unit forms (Fig. 1) with each Cd^II atom in a six-coordinate N₃O₃ ligand environment. The Cd—X (X = N or O) distances are reasonable, spanning the range 2.304 (2)–2.332 (3) Å. However, the coordination angles vary widely [X–Cd–X ranges: cis 71.15 (10)–115.79 (9)°; trans 142.36 (8)–159.48 (9)°]; the result is a rather distorted octahedral geometry around Cd1. Selected geometric parameters are shown in Table 1; the bridging Cd—O distances are the shortest in the coordination sphere, 2.304 (2) and 2.310 (2) Å, resulting in a Cd⋯Cd separation of 3.700 (3) Å. This value is slightly larger than the mean for similar environments found in the CSD (3.61 Å for 885 cases), though well within the sample standard deviation (0.22 Å).

Table 1
Selected bond lengths (Å)

Cd1—O1Bⁱ	2.304 (2)	Cd1—N1A	2.323 (3)
Cd1—O1B	2.310 (2)	Cd1—O1C	2.329 (2)
Cd1—N2A	2.310 (3)	Cd1—N1B	2.332 (3)
Symmetry code: (i) -x+1, -y+1, -z+1.

Figure 1
Displacement ellipsoid plot of (I)

(with 40% probability ellipsoids), showing the dimeric unit with atom and ring labelling. Interactions within the dimeric unit are also shown, C—H⋯O as dashed lines, C—O⋯π(ring) as double-dashed lines. For symmetry codes see Tables 2

and 3

; additional symmetry code: (i) 1 − x, 1 − y, 1 − z.

3. Supramolecular features

The crystal structure, made up of isolated dimers, is sustained by three different types of non-covalent interaction, viz., hydrogen bonds (Table 2), C=O⋯π and nitrate(π)⋯π contacts (Table 3). These interactions can be clearly differentiated according to the substructure that they support:

Table 2
Hydrogen-bonding interactions (Å, °) in (I)

Cg1 is the centroid of the N1A/C1A–C5A ring.

Int.#	D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
#1	C10A—H10A⋯O1C	0.93	2.52	3.143 (5)	124
#2	O4B—H4BO⋯O3Cⁱⁱ	0.84 (3)	1.83 (3)	2.670 (5)	176 (6)
#3	C7A—H7A⋯O2Bⁱⁱⁱ	0.93	2.42	3.339 (4)	168
#4	C8A—H8A⋯O2Cⁱⁱⁱ	0.93	2.59	3.51 (4)	167
#5	C9A—H9A⋯O4B^iv	0.93	2.53	3.186 (5)	127
#6	C8B—H8BC⋯O1M	0.960	2.54	3.361 (8)	144
#7	O1M—H1M⋯O3Bⁱⁱⁱ	0.85 (5)	2.42 (9)	2.951 (9)	121 (9)
#8	C1M—H1M3⋯Cg1	0.96	2.78	3.640	149
Symmetry codes: (ii) 1 + x, y, z; (iii) x, 1 + y, z; (iv) −1 + x, 1 + y, z.

Table 3
X—O⋯π interactions (Å, °)in (I)

Cg1 is the centroid of the N1A/C1A–C5A ring and Cg2 is the centroid of the N2A/C6A–C10A ring.

Int.#	X—O⋯Cg	O⋯Cg	X—O⋯Cg
#9	C6B—O2B⋯Cg2ⁱ	3.637 (3)	126.6 (2)
#10	N1C—O2C⋯Cg1ⁱ	3.442 (4)	104.2 (2)
Symmetry code: (i) 1 − x, 1 − y, 1 − z.

a) Contacts #1 (Table 2) and #9, #10 (Table 3) are internal to the dinuclear motif, as shown in Fig. 1. The first one links the bipyridine C10A—H10A group with the coordinating nitrate oxygen O1C. Contact #9 is a typical lone pair–π interaction with a dihedral angle of 72.19° between the carboxylate and the ring plane, and a C—O⋯Cg2 angle of 126.63°. These values are close to those for the ideal geometry (90° and 120°, respectively) when a lone pair provided by a carbonyl oxygen points toward the centroid of an aromatic ring (Egli & Sarkhel, 2007 ). By contrast, in contact #10 the orientation of the nitrate plane is more or less parallel to the ring plane (6.84°), suggesting a π–π interaction with the π-orbitals of the nitrate fragment interacting with those of the aromatic ring. A similar argument has already been applied by Frontera et al. (2011 ) and García-Raso et al. (2009 ) when nitrate anions interact with pyrimidinium rings. These carbonyl(lone pair)⋯π(ring) (#9) and nitrate(π)⋯π(ring) (#10) interactions in (I) fulfill a relevant function, serving to strengthen the dimeric unit (Fig. 1).

b) Strong intermolecular O—H⋯O contacts #2 (Table 2) involving the hydrogen atom of the free carboxylic acid group of the mepydcH⁻ ligand with a non-bonded oxygen atom of a nitrate ligand, has the pivotal action of linking the dimers along a, forming chains parallel to [100] (Fig. 2).

Figure 2
The [100] chain defined by O—H⋯O interaction #2 (Table 2

c) C—H⋯O interactions #3, #4 and #5 (Table 2), in turn, serve to link the above chains laterally along b, to form 2D substructures parallel to (001) (Fig. 3a). These planes juxtapose along [001] with rather weak direct interactions. In the process, however, significant columnar voids parallel to the chains are formed (with a volume 13% of the total cell volume, Fig. 3b) in which the partial occupancy methanol solvate molecules reside. These are not free, but enter instead into a number of weak C—H⋯O, O—H⋯O and C—H⋯π interactions (#6, #7 and #8 in Table 2) linking them to a framework of complex molecules, further stabilizing the structure.

Figure 3
Two projections along [100], presenting (within square brakets) views of the two-dimensional substructures parallel to (001), formed by the [100] columns linked along b. (a) Showing a single plane, with interaction details. (b) Displaying the columnar voids (coloured) generated by juxtaposition of the planes.

4. ATR (attenuated total reflectance) FT–IR spectroscopy

The IR spectra of mepydcH₂, 2.2′-bipyridine and (I) were recorded on an Agilent Cary 630 FT–IR spectrometer with Varian Resolutions Pro software, using a Diamond ATR accessory. The FT–IR spectrum of (I) (Fig. 4) was recorded in the 4000–600 cm⁻¹ range, and confirms the structural data indicating the presence of the coordinating nitrate and mepydcH⁻ anions. Bands due to the unidentate NO₃⁻ group were found at 1478 and 1298 cm⁻¹ and appear due to the ν_asym(ONO) and ν_sym(ONO) vibrations, with a shoulder at 1010 cm⁻¹ due to the ν(NO) stretching modes of nitrate groups (Nakamoto, 1997 ). The carboxylic acid group (COOH) of the mepydcH⁻ ligand in complex (I) is identified by a weak band at 3083 cm⁻¹, ν(OH) stretching for a hydrogen-bonded system (Alisir et al., 2013 ), and a very strong band at 1738 cm⁻¹, ν(C=O) stretch. The deprotonated carboxylate (COO⁻) is characterized by the asymmetric and symmetric stretching modes ν_as at 1593 cm⁻¹ and ν_s at 1322 cm⁻¹. This confirms the unidentate coordination of the carboxylate O atom, with the difference between these frequencies being > 200 cm⁻¹(Δ = ν_as − ν_s = 271 cm⁻¹) (Deacon & Phillips, 1980 ). Finally, around 1400 cm⁻¹, a set of three bands appears (1412, 1391 and 1369 cm⁻¹) of almost equal intensity due to the ν(C=C) + ν(C=N) vibrations from the coordinating 2,2′-bipyridine ligand (Yan et al., 2011 ).

Figure 4
FT–IR spectrum of (I)

5. Synthesis and crystallization

Solid 2,2′-bipyridine (0.031 g, 0.20 mmol) was added to a solution prepared by disolving Cd(NO₃)·4H₂O (0.062 g, 0.20 mmol) and mepydcH₂ (0.036 g, 0.20 mmol) in MeOH (4.0 mL). The mixture was stirred to dissolve the 2,2′-bipyridine and was then allowed to stand undisturbed at room temperature in an uncovered 10 mL beaker. Colourless single crystals of compound (I) suitable for X-ray diffraction were obtained within 8 h. The crystals were separated by filtration, washed with MeOH (2 x 2 mL) and diethyl ether (2 x 3 mL) (yield: 0.045 g, 44%).

6. Refinement

Relevant crystallographic data for (I) as well as pertinent experimental details are provided in Table 4. H atoms bonded to C were found in a difference Fourier map, but were then idealized and refined as riding atoms; C—H_arom: 0.93 Å, U_eq(H) = 1.2U_eq(C); C—H_methyl: 0.97 Å, U_eq(H) = 1.5U_eq(C). The O—H hydrogen atom was refined with a restrained O—H distance [0.85 (1)Å], and with U(H) = 1.2U_eq(O). The methanol solvate was refined at half occupancy.

Table 4
Experimental details

Crystal data
Chemical formula	[Cd₂(C₈H₆NO₄)₂(NO₃)₂(C₁₀H₈N₂)₂]·CH₄O
M_r	1053.50
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	295
a, b, c (Å)	8.4096 (5), 10.9626 (6), 11.5056 (4)
α, β, γ (°)	71.241 (4), 86.537 (4), 86.803 (5)
V (Å³)	1001.79 (9)
Z	1
Radiation type	Mo Kα
μ (mm⁻¹)	1.14
Crystal size (mm)	0.36 × 0.14 × 0.10

Data collection
Diffractometer	Oxford Diffraction Gemini CCD S Ultra
Absorption correction	Multi-scan (CrysAlis PRO; Oxford Diffraction, 2009 $[Oxford Diffraction (2009). CrysAlis PRO. Oxford Diffraction Ltd, Abingdon, England.]$ )
No. of measured, independent and observed [I > 2σ(I)] reflections	21744, 4819, 4155
R_int	0.057
(sin θ/λ)_max (Å⁻¹)	0.684

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.092, 1.01
No. of reflections	4819
No. of parameters	298
No. of restraints	4
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	1.07, −0.74
Computer programs: CrysAlis PRO (Oxford Diffraction, 2009 $[Oxford Diffraction (2009). CrysAlis PRO. Oxford Diffraction Ltd, Abingdon, England.]$ ), SHELXS97 and SHELXTL (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ) and PLATON (Spek, 2009 ).

Supporting information

CCDC reference: 1409269

Crystal structure: contains datablocks I, global. DOI: https://doi.org/10.1107/S2056989015012384/sj5468sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989015012384/sj5468Isup2.hkl

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Oxford Diffraction, 2009); cell refinement: CrysAlis PRO (Oxford Diffraction, 2009); data reduction: CrysAlis PRO (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015) and PLATON (Spek, 2009).

Bis(µ-3-carboxy-6-methylpyridine-2-carboxylato)-κ³N,O²:O²;κ³O²:N,O²-bis[(2,2'-bipyridine-κ²N,N'))(nitrato-κO)cadmium] methanol monosolvate top

Crystal data top

[Cd₂(C₈H₆NO₄)₂(NO₃)₂(C₁₀H₈N₂)₂]·CH₄O	Z = 1
M_r = 1053.50	F(000) = 526
Triclinic, P1	D_x = 1.746 Mg m⁻³
a = 8.4096 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 10.9626 (6) Å	Cell parameters from 2675 reflections
c = 11.5056 (4) Å	θ = 3.8–28.8°
α = 71.241 (4)°	µ = 1.14 mm⁻¹
β = 86.537 (4)°	T = 295 K
γ = 86.803 (5)°	Block, colourless
V = 1001.79 (9) Å³	0.36 × 0.14 × 0.10 mm

Data collection top

Oxford Diffraction Gemini CCD S Ultra diffractometer	4155 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.057
ω scans, thick slices	θ_max = 29.1°, θ_min = 3.6°
Absorption correction: multi-scan (CrysAlis PRO; Oxford Diffraction, 2009)	h = −11→11
	k = −14→14
21744 measured reflections	l = −15→15
4819 independent reflections

Refinement top

Refinement on F²	4 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F² > 2σ(F²)] = 0.036	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.092	w = 1/[σ²(F_o²) + (0.0394P)² + 1.5425P] where P = (F_o² + 2F_c²)/3
S = 1.01	(Δ/σ)_max < 0.001
4819 reflections	Δρ_max = 1.07 e Å⁻³
298 parameters	Δρ_min = −0.74 e Å⁻³

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Cd1	0.47993 (3)	0.63548 (2)	0.35527 (2)	0.01961 (9)
N1A	0.6981 (3)	0.7364 (3)	0.3922 (3)	0.0229 (6)
N2A	0.4198 (3)	0.8540 (3)	0.3047 (2)	0.0223 (6)
C1A	0.8378 (4)	0.6740 (4)	0.4272 (3)	0.0279 (7)
H1A	0.8516	0.5882	0.4306	0.033*
C2A	0.9614 (4)	0.7331 (4)	0.4581 (3)	0.0292 (8)
H2A	1.0575	0.6883	0.4821	0.035*
C3A	0.9393 (4)	0.8601 (4)	0.4526 (3)	0.0312 (8)
H3A	1.0204	0.9020	0.4740	0.037*
C4A	0.7968 (4)	0.9252 (4)	0.4152 (3)	0.0286 (7)
H4A	0.7812	1.0114	0.4104	0.034*
C5A	0.6771 (4)	0.8603 (3)	0.3851 (3)	0.0196 (6)
C6A	0.5211 (4)	0.9244 (3)	0.3409 (3)	0.0201 (6)
C7A	0.4801 (4)	1.0501 (3)	0.3369 (3)	0.0263 (7)
H7A	0.5504	1.0976	0.3629	0.032*
C8A	0.3343 (4)	1.1041 (3)	0.2940 (3)	0.0286 (8)
H8A	0.3048	1.1877	0.2920	0.034*
C9A	0.2327 (4)	1.0328 (3)	0.2540 (3)	0.0303 (8)
H9A	0.1348	1.0679	0.2230	0.036*
C10A	0.2801 (4)	0.9084 (3)	0.2614 (3)	0.0280 (7)
H10A	0.2116	0.8599	0.2351	0.034*
O1B	0.6097 (3)	0.4384 (2)	0.44192 (19)	0.0216 (5)
O2B	0.7028 (3)	0.2598 (2)	0.4031 (2)	0.0256 (5)
O3B	0.8147 (3)	0.1816 (3)	0.1644 (3)	0.0390 (6)
O4B	0.9923 (3)	0.2717 (3)	0.2400 (3)	0.0340 (6)
H4BO	1.004 (6)	0.344 (2)	0.248 (4)	0.051 (14)*
N1B	0.5964 (3)	0.5661 (3)	0.1972 (2)	0.0200 (5)
C1B	0.6745 (4)	0.4503 (3)	0.2349 (3)	0.0185 (6)
C2B	0.7605 (4)	0.3994 (3)	0.1523 (3)	0.0226 (7)
C3B	0.7607 (5)	0.4714 (4)	0.0288 (3)	0.0316 (8)
H3B	0.8164	0.4402	−0.0288	0.038*
C4B	0.6796 (5)	0.5880 (4)	−0.0090 (3)	0.0343 (9)
H4B	0.6799	0.6361	−0.0919	0.041*
C5B	0.5963 (4)	0.6345 (3)	0.0780 (3)	0.0255 (7)
C6B	0.6608 (4)	0.3736 (3)	0.3714 (3)	0.0185 (6)
C7B	0.8543 (4)	0.2739 (3)	0.1893 (3)	0.0265 (7)
C8B	0.5036 (5)	0.7606 (4)	0.0418 (3)	0.0376 (9)
H8BA	0.5131	0.7999	−0.0457	0.056*
H8BB	0.3934	0.7462	0.0669	0.056*
H8BC	0.5448	0.8166	0.0811	0.056*
N1C	0.1872 (3)	0.5118 (3)	0.2872 (2)	0.0248 (6)
O1C	0.2228 (3)	0.6168 (3)	0.3000 (3)	0.0350 (6)
O2C	0.2871 (3)	0.4227 (3)	0.2993 (3)	0.0341 (6)
O3C	0.0460 (3)	0.5009 (3)	0.2619 (3)	0.0374 (6)
O1M	0.7710 (10)	0.9624 (9)	0.0748 (8)	0.072 (2)	0.5
H1M	0.816 (4)	1.0346 (13)	0.046 (17)	0.18 (9)*	0.5
C1M	0.8993 (11)	0.8676 (10)	0.0932 (8)	0.060 (3)	0.5
H1M1	0.9936	0.9068	0.0490	0.090*	0.5
H1M2	0.8713	0.7994	0.0637	0.090*	0.5
H1M3	0.9189	0.8331	0.1792	0.090*	0.5

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.02114 (13)	0.01596 (13)	0.02201 (13)	0.00148 (9)	−0.00289 (9)	−0.00650 (9)
N1A	0.0207 (14)	0.0214 (14)	0.0274 (14)	−0.0001 (11)	−0.0030 (11)	−0.0087 (11)
N2A	0.0226 (14)	0.0178 (14)	0.0259 (14)	0.0016 (11)	−0.0031 (11)	−0.0062 (11)
C1A	0.0255 (17)	0.0252 (18)	0.0331 (18)	0.0027 (14)	−0.0037 (14)	−0.0095 (15)
C2A	0.0201 (16)	0.038 (2)	0.0293 (18)	−0.0008 (15)	−0.0038 (14)	−0.0105 (16)
C3A	0.0261 (18)	0.040 (2)	0.0324 (19)	−0.0088 (16)	−0.0041 (15)	−0.0166 (16)
C4A	0.0336 (19)	0.0228 (18)	0.0327 (18)	−0.0046 (15)	−0.0020 (15)	−0.0129 (15)
C5A	0.0216 (15)	0.0188 (16)	0.0192 (14)	−0.0028 (12)	0.0002 (12)	−0.0069 (12)
C6A	0.0231 (16)	0.0182 (16)	0.0181 (14)	−0.0022 (13)	0.0004 (12)	−0.0048 (12)
C7A	0.0312 (18)	0.0193 (17)	0.0279 (17)	−0.0039 (14)	0.0003 (14)	−0.0069 (14)
C8A	0.036 (2)	0.0169 (17)	0.0293 (18)	0.0031 (14)	0.0055 (15)	−0.0043 (14)
C9A	0.0277 (18)	0.0239 (18)	0.0374 (19)	0.0089 (15)	−0.0044 (15)	−0.0083 (15)
C10A	0.0248 (17)	0.0228 (18)	0.0363 (19)	0.0030 (14)	−0.0067 (14)	−0.0089 (15)
O1B	0.0278 (12)	0.0180 (11)	0.0185 (11)	0.0049 (9)	0.0004 (9)	−0.0062 (9)
O2B	0.0328 (13)	0.0168 (12)	0.0271 (12)	0.0025 (10)	−0.0033 (10)	−0.0073 (10)
O3B	0.0471 (17)	0.0307 (15)	0.0461 (16)	0.0020 (12)	−0.0037 (13)	−0.0221 (13)
O4B	0.0265 (13)	0.0314 (15)	0.0481 (16)	0.0076 (11)	−0.0078 (11)	−0.0182 (13)
N1B	0.0196 (13)	0.0185 (14)	0.0216 (13)	−0.0010 (11)	−0.0033 (10)	−0.0055 (11)
C1B	0.0173 (14)	0.0193 (16)	0.0208 (15)	−0.0016 (12)	−0.0047 (12)	−0.0082 (12)
C2B	0.0197 (16)	0.0245 (17)	0.0259 (16)	−0.0017 (13)	−0.0012 (13)	−0.0110 (14)
C3B	0.038 (2)	0.035 (2)	0.0234 (17)	0.0039 (16)	0.0038 (15)	−0.0126 (15)
C4B	0.047 (2)	0.032 (2)	0.0203 (16)	0.0064 (17)	−0.0004 (15)	−0.0051 (15)
C5B	0.0295 (18)	0.0226 (17)	0.0234 (16)	0.0013 (14)	−0.0052 (13)	−0.0055 (13)
C6B	0.0156 (14)	0.0181 (16)	0.0237 (15)	−0.0006 (12)	−0.0029 (12)	−0.0088 (12)
C7B	0.0265 (17)	0.0270 (19)	0.0283 (17)	0.0012 (14)	0.0046 (14)	−0.0135 (15)
C8B	0.051 (2)	0.032 (2)	0.0256 (18)	0.0103 (18)	−0.0058 (17)	−0.0053 (16)
N1C	0.0250 (15)	0.0292 (16)	0.0218 (13)	−0.0013 (12)	−0.0019 (11)	−0.0104 (12)
O1C	0.0264 (13)	0.0315 (15)	0.0561 (17)	0.0001 (11)	−0.0092 (12)	−0.0254 (13)
O2C	0.0268 (13)	0.0282 (14)	0.0484 (16)	0.0019 (11)	−0.0004 (11)	−0.0143 (12)
O3C	0.0253 (13)	0.0381 (16)	0.0555 (17)	−0.0034 (11)	−0.0108 (12)	−0.0224 (14)
O1M	0.078 (6)	0.075 (6)	0.077 (5)	−0.016 (5)	−0.010 (4)	−0.039 (5)
C1M	0.052 (6)	0.097 (9)	0.036 (5)	−0.018 (6)	−0.010 (4)	−0.023 (5)

Geometric parameters (Å, º) top

Cd1—O1Bⁱ	2.304 (2)	O1B—C6B	1.281 (4)
Cd1—O1B	2.310 (2)	O2B—C6B	1.220 (4)
Cd1—N2A	2.310 (3)	O3B—C7B	1.205 (4)
Cd1—N1A	2.323 (3)	O4B—C7B	1.326 (4)
Cd1—O1C	2.329 (2)	O4B—H4BO	0.845 (10)
Cd1—N1B	2.332 (3)	N1B—C5B	1.336 (4)
N1A—C5A	1.336 (4)	N1B—C1B	1.348 (4)
N1A—C1A	1.342 (4)	C1B—C2B	1.397 (4)
N2A—C10A	1.336 (4)	C1B—C6B	1.525 (4)
N2A—C6A	1.349 (4)	C2B—C3B	1.386 (5)
C1A—C2A	1.377 (5)	C2B—C7B	1.496 (5)
C1A—H1A	0.9300	C3B—C4B	1.367 (5)
C2A—C3A	1.375 (5)	C3B—H3B	0.9300
C2A—H2A	0.9300	C4B—C5B	1.398 (5)
C3A—C4A	1.378 (5)	C4B—H4B	0.9300
C3A—H3A	0.9300	C5B—C8B	1.497 (5)
C4A—C5A	1.387 (5)	C8B—H8BA	0.9600
C4A—H4A	0.9300	C8B—H8BB	0.9600
C5A—C6A	1.490 (4)	C8B—H8BC	0.9600
C6A—C7A	1.389 (5)	N1C—O2C	1.230 (4)
C7A—C8A	1.379 (5)	N1C—O3C	1.260 (4)
C7A—H7A	0.9300	N1C—O1C	1.261 (4)
C8A—C9A	1.380 (5)	O1M—C1M	1.431 (8)
C8A—H8A	0.9300	O1M—H1M	0.855 (10)
C9A—C10A	1.377 (5)	C1M—H1M1	0.9600
C9A—H9A	0.9300	C1M—H1M2	0.9600
C10A—H10A	0.9300	C1M—H1M3	0.9600

O1Bⁱ—Cd1—O1B	73.38 (8)	N2A—C10A—C9A	123.1 (3)
O1Bⁱ—Cd1—N2A	101.83 (9)	N2A—C10A—H10A	118.4
O1B—Cd1—N2A	159.48 (9)	C9A—C10A—H10A	118.4
O1Bⁱ—Cd1—N1A	94.90 (9)	C6B—O1B—Cd1ⁱ	128.9 (2)
O1B—Cd1—N1A	89.17 (9)	C6B—O1B—Cd1	118.42 (19)
N2A—Cd1—N1A	71.15 (10)	Cd1ⁱ—O1B—Cd1	106.62 (8)
O1Bⁱ—Cd1—O1C	88.36 (9)	C7B—O4B—H4BO	109 (3)
O1B—Cd1—O1C	112.97 (9)	C5B—N1B—C1B	120.4 (3)
N2A—Cd1—O1C	86.44 (9)	C5B—N1B—Cd1	124.9 (2)
N1A—Cd1—O1C	157.56 (10)	C1B—N1B—Cd1	114.7 (2)
O1Bⁱ—Cd1—N1B	142.36 (8)	N1B—C1B—C2B	121.7 (3)
O1B—Cd1—N1B	71.66 (8)	N1B—C1B—C6B	117.5 (3)
N2A—Cd1—N1B	115.79 (9)	C2B—C1B—C6B	120.7 (3)
N1A—Cd1—N1B	98.09 (9)	C3B—C2B—C1B	117.6 (3)
O1C—Cd1—N1B	92.65 (9)	C3B—C2B—C7B	118.4 (3)
C5A—N1A—C1A	119.8 (3)	C1B—C2B—C7B	124.1 (3)
C5A—N1A—Cd1	117.1 (2)	C4B—C3B—C2B	120.4 (3)
C1A—N1A—Cd1	123.0 (2)	C4B—C3B—H3B	119.8
C10A—N2A—C6A	118.9 (3)	C2B—C3B—H3B	119.8
C10A—N2A—Cd1	123.4 (2)	C3B—C4B—C5B	119.6 (3)
C6A—N2A—Cd1	116.7 (2)	C3B—C4B—H4B	120.2
N1A—C1A—C2A	122.1 (3)	C5B—C4B—H4B	120.2
N1A—C1A—H1A	119.0	N1B—C5B—C4B	120.4 (3)
C2A—C1A—H1A	119.0	N1B—C5B—C8B	117.7 (3)
C3A—C2A—C1A	118.3 (3)	C4B—C5B—C8B	121.9 (3)
C3A—C2A—H2A	120.9	O2B—C6B—O1B	126.7 (3)
C1A—C2A—H2A	120.9	O2B—C6B—C1B	118.0 (3)
C2A—C3A—C4A	119.9 (3)	O1B—C6B—C1B	115.3 (3)
C2A—C3A—H3A	120.0	O3B—C7B—O4B	120.6 (3)
C4A—C3A—H3A	120.0	O3B—C7B—C2B	122.0 (3)
C3A—C4A—C5A	118.9 (3)	O4B—C7B—C2B	117.1 (3)
C3A—C4A—H4A	120.5	C5B—C8B—H8BA	109.5
C5A—C4A—H4A	120.5	C5B—C8B—H8BB	109.5
N1A—C5A—C4A	121.0 (3)	H8BA—C8B—H8BB	109.5
N1A—C5A—C6A	116.7 (3)	C5B—C8B—H8BC	109.5
C4A—C5A—C6A	122.3 (3)	H8BA—C8B—H8BC	109.5
N2A—C6A—C7A	121.0 (3)	H8BB—C8B—H8BC	109.5
N2A—C6A—C5A	116.6 (3)	O2C—N1C—O3C	121.1 (3)
C7A—C6A—C5A	122.4 (3)	O2C—N1C—O1C	121.0 (3)
C8A—C7A—C6A	119.4 (3)	O3C—N1C—O1C	117.9 (3)
C8A—C7A—H7A	120.3	N1C—O1C—Cd1	118.4 (2)
C6A—C7A—H7A	120.3	C1M—O1M—H1M	104.7 (13)
C7A—C8A—C9A	119.4 (3)	O1M—C1M—H1M1	109.5
C7A—C8A—H8A	120.3	O1M—C1M—H1M2	109.5
C9A—C8A—H8A	120.3	H1M1—C1M—H1M2	109.5
C10A—C9A—C8A	118.2 (3)	O1M—C1M—H1M3	109.5
C10A—C9A—H9A	120.9	H1M1—C1M—H1M3	109.5
C8A—C9A—H9A	120.9	H1M2—C1M—H1M3	109.5

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bonding interactions (Å, °) in (I) top

Cg1 is the centroid of the N1A/C1A–C5A ring.

Int.#	D—H···A	D—H	H···A	D···A	D—H···A
#1	C10A—H10A···O1C	0.93	2.52	3.143 (5)	124
#2	O4B—H4BO···O3Cⁱⁱ	0.84 (3)	1.83 (3)	2.670 (5)	176 (6)
#3	C7A—H7A···O2Bⁱⁱⁱ	0.93	2.42	3.339 (4)	168
#4	C8A—H8A···O2Cⁱⁱⁱ	0.93	2.59	3.51 (4)	167
#5	C9A—H9A···O4B^iv	0.93	2.53	3.186 (5)	127
#6	C8B—H8BC···O1M	0.960	2.54	3.361 (8)	144
#7	O1M—H1M···O3Bⁱⁱⁱ	0.85 (5)	2.42 (9)	2.951 (9)	121 (9)
#8	C1M—H1M3···Cg1	0.96	2.78	3.640	149

Symmetry codes: (ii) 1 + x, y, z; (iii) x, 1 + y, z; (iv) -1 + x, 1 + y, z.

X—O···π interactions (Å, °)in (I) top

Cg1 is the centroid of the N1A/C1A–C5A ring and Cg2 is the centroid of the N2A/C6A–C10A ring.

Int.#	X—O···Cg	O···Cg	X—O···Cg
#9	C6B-O2B···Cg2ⁱ	3.637 (3)	126.6 (2)
#10	N1C-O2C···Cg1ⁱ	3.442 (4)	104.2 (2)

Symmetry code: (i) 1 - x, 1 - y, 1 - z.

Acknowledgements

The authors acknowledge the Universidad de La Frontera (Proyecto DIUFRO DI15–0027) and ANPCyT (project No. PME 2006–01113) for the purchase of the Oxford Gemini CCD diffractometer.

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