Crystal structure of {2,2′-[N,N′-bis­(pyridin-2-yl­meth­yl)cyclo­hexane-trans-1,2-diyldi(nitrilo)]di­acetato}­cobalt(III) hexa­fluorido­phosphate

McLauchlan, C.C.; Kissel, D.S.; Herlinger, A.W.

doi:10.1107/S2056989015005149

research communications

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ISSN: 2056-9890

Volume 71| Part 4| April 2015| Pages 380-384

doi:10.1107/S2056989015005149

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Crystal structure of {2,2′-[N,N′-bis(pyridin-2-ylmethyl)cyclohexane-trans-1,2-diyldi(nitrilo)]diacetato}cobalt(III) hexafluoridophosphate

Craig C. McLauchlan,^a ^* Daniel S. Kissel ^b ‡ and Albert W. Herlinger ^b

^aDepartment of Chemistry, Illinois State University, Campus Box 4160, Normal, IL 61790-4160, USA, and ^bDepartment of Chemistry and Biochemistry, Loyola University Chicago, Chicago, IL 60626, USA
^*Correspondence e-mail: mclauchlan@illinoisstate.edu

Edited by M. Zeller, Youngstown State University, USA (Received 24 February 2015; accepted 13 March 2015; online 21 March 2015)

The title compound [Co(C₂₂H₂₆N₄O₄)]PF₆, commonly known as [Co(bpcd)]PF₆, where bpcd²⁻ is derived from the historical ligand name N,N′-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N′-diacetate, crystallized by slow evaporation of a saturated acetonitrile solution in air. The cation of the hexafluoridophosphate salt has the Co^III atom in a distorted octahedral coordination geometry provided by an N₄O₂ donor atom set. The acetate groups, which are oriented trans with respect to each other, exhibit monodentate coordination whereas the pyridyl N atoms are coordinating in a cis configuration. The geometry of the cation is compared to the geometries of other diamino diacetate complexes with Co^III.

Keywords: crystal structure; polyaminocarboxylic acid; cobalt(III); chelating ligand.

CCDC reference: 1053810

1. Chemical context

Polyaminocarboxylic acids are of considerable interest as complexation reagents for a variety of metal ions in a wide range of applications (Weaver & Kappelmann, 1964 ; Weiner & Thakur, 1995 ; Caravan et al., 1997a ,b ; Geraldes, 1999 ; Heitzmann et al., 2009 ). The title compound, [Co(bpcd)]PF₆, (I), was prepared from N,N′-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N′-diacetic acid (H₂bpcd), a symmetrically disubstituted polyaminocarboxylic acid featuring a chiral trans-diaminocyclohexane backbone.

The ligand precursor, H₂bpcd, belongs to a relatively small group of diamino diacetic acids that contain softer aromatic nitrogen donor groups (Fig. 1) (Caravan et al., 1997a; Heitzmann et al., 2009; Kissel et al., 2014 ). The preorganized ligand precursor H₂bpcd is of interest as a novel candidate for selective and efficient actinide(III)/lanthanide(III) separations. Preorganization of a ligand can reduce the pre-orientation energy required for metal ion complexation and provide improved metal–ligand complex stability (Rizkalla et al., 1987 ; Choppin et al., 2006 ; Ogden et al., 2012 ). The addition of aromatic functionalities, such as pyridine and pyrazine, may increase ligand selectivity for softer metal ions and provide greater stability towards radiolysis (Heitzmann et al., 2009). The members of this group of diacetic acids, however, differ in the nature of the diamine backbone.

Figure 1
The diamino diacetic acids, H₂bped (A) and gem-H₂bped (B), where bped stands for bis(2-pyridylmethyl)-1,2-diaminoethane diacetate, H₂bpcd (C), and H₂bppd (D), where bppd stands for bis(2-pyridylmethyl)-1,3-diaminopropane diacetate.

The ethylenediamine backbone is a classic scaffold that has been used for the construction of many polydentate ligands. The amine N atoms are ideal for functionalization, which allows different donor atom groups to be incorporated into a ligand's design. The close proximity of the diamine nitrogens also maximizes the number of possible five- and six-membered chelate rings capable of forming upon metal ion complexation. H₂bped (A) is a hexadentate 2-pyridylmethyl-substituted diacetic acid based on this classic scaffold (Lacoste et al., 1965 ; Caravan et al., 1997a). gem-H₂bped (B) is a very closely related 2-pyridylmethyl-substituted diacetic acid that is also based on the ethylenediamine scaffold. In this case, however, both pyridine substituents are bonded to the same amine N atom (Heitzmann et al., 2009). The C—C chain length between the N atoms in the diamine backbone of these ligands allows for the formation of five-membered chelate rings. Hancock has shown the formation of five-membered chelate rings to be more favourable for larger metal ions than for smaller metal ions (Hancock & Martell, 1989 ). The ligand precursor, H₂bpcd (C), for the title compound is similar to A and B, but it incorporates the ethylenediamine backbone into a cyclohexyl group. Restricted rotation about the C—C bonds in the cyclohexane ring fixes the positions of the trans diamine nitrogen atoms and favourably preorganizes these donor groups for metal ion complexation. Consequently, the trans amine groups are constrained into a conformation that is pre-oriented favorably for binding and results in a complex of increased stability (Rizkalla et al., 1987; Choppin et al., 2006; Ogden et al., 2012). In contrast, H₂bppd (D) features a 1,3-diaminopropane backbone that provides greater flexibility compared to A, B, or C with their shorter backbones. Further, the increased chain length of the propylene linker allows a six-membered chelate ring to form upon metal complexation. Formation of six-membered chelate rings in complexes with smaller metal ions has been shown to increase the stability of the complex relative to five-membered rings (Hancock & Martell, 1989). Here, we report the structure of a Co^III complex with bpcd²⁻, C.

2. Structural commentary

The structure of the [Co(bpcd)]⁺ cation in the title compound is shown in Fig. 2 and selected geometric parameters are listed in Table 1. The cation is very similar to the structures of the [Co(bped)]⁺ and [Co(bppd)]⁺ complex ions. Nearly all of the Co—O_ac bond lengths for the five structures given in Table 1 are within experimental error of each other. One of the Co—O_ac bond lengths in the [Co(bppd)]⁺ cation, however, is slightly shorter than the others. The C—O and C=O bond lengths are also quite similar. There are, however, some variations in the bond lengths and angles as shown in Tables 1 and 2. The Co—N_am bond length in the [Co(bpcd)]⁺ cation is slightly shorter than the Co—N_am bond lengths reported for the two [Co(bppd)]⁺ cations given in Table 1. They are, however, slightly longer than those reported for the [Co(bped)]⁺ structures. Similarly, the N_am1—Co—N_am2 bond angle in [Co(bpcd)]⁺ is close to ideal (90°), whereas the N_am1—Co—N_am2 angles in the [Co(bppd)]⁺ structures are somewhat larger than ideal and somewhat smaller than ideal in the [Co(bped)]⁺ structures (Table 2). The O_ac1—Co—O_ac2 bond angles for the five structures in Table 2 are all close to ideal (180°), with the largest deviation from linearity observed in the[Co(bpcd)]⁺ cation. The 176.1° O_ac1—Co—O_ac2 bond angle in [Co(bpcd)]⁺ is 2° smaller than the average (178.5°) of the bond angles reported for the [Co(bped)]⁺ and [Co(bppd)]⁺ cations. Finally, the Co^III in the title compound is situated directly in the N₄ plane of the equatorial nitrogen atoms, whereas in three of the other four structures the Co^III lays slightly out-of the plane (Table 1). The solid-state structural parameters for [Co(bpcd)]⁺, which are very similar to those for Co(bped)⁺, suggest that the ligand precusor H₂(bpcd), with its preorganized arrangement, may provide greater metal ion complex stability as well as be selective for actinides(III) over lanthanides(III) as demonstrated for gem-H₂(bped). (Heitzmann et al., 2009)

Table 1
Bond distances (Å) and experimental data for different [Co(bpad)]⁺ structures

Bond (Å)	Co(bped)^{+ a}	Co(bped)^{+ b}	Co(bppd)^{+ c} 1	Co(bppd)^{+ c} 2	Co(bpcd)^{+ d}
Co–O_ac1	1.888 (1)	1.878 (2)	1.8828 (11)	1.8875 (10)	1.8869 (8)
Co–O_ac2	1.889 (2)	1.888 (2)	1.8899 (11)	1.8830 (11)	*
Co–N_am1	1.941 (2)	1.937 (2)	1.9625 (13)	1.9654 (12)	1.9548 (9)
Co–N_am2	1.974 (2)	1.941 (2)	1.9641 (13)	1.9645 (12)	*
Co–N_pyr1	1.944 (2)	1.960 (2)	1.9484 (13)	1.9403 (13)	1.9448 (9)
Co–N_pyr2	1.954 (2)	1.958 (2)	1.9397 (13)	1.9576 (13)	*
C–O_ac1	1.294 (2)	1.298 (4)	1.2973 (18)	1.3054 (18)	1.3029 (13)
C=O_ac1	1.212 (3)	1.218 (3)	1.2265 (18)	1.219 (2)	1.2212 (14)
C–O_ac2	1.289 (3)	1.299 (3)	1.3035 (19)	1.2971 (19)	*
C=O_ac2	1.210 (3)	1.213 (3)	1.2201 (19)	0.0030 (6)	*
Co above N/N/N/N plane	0.000^†	0.012^†	0.0026 (6)	0.0030 (6)	0**
Temp, K	298	293	100	100	100
Notes: (a) Mandel & Douglas (1989); (b) Caravan et al. (1997a); (c) two cations in asymmetric unit (McLauchlan et al., 2013); (d) this work; () N/A – symmetry equivalent; (†) standard uncertainty unavailable; (*) N/A – sits on a special position.

Table 2
Selected bond angles (°) for different [Co(bpad)]⁺ structures

Angle, °	Co(bped)^{+ a}	Co(bped)^{+ b}	Co(bppd)^{+ c} 1	Co(bppd)^{+ c} 2	Co(bpcd)^{+ d}
O_ac1–Co–O_ac2	178.8 (1)	178.53 (8)	178.47 (5)	178.36 (5)	176.08 (5)
N_am1–Co–N_am2	82.0 (1)	88.87 (9)	95.91 (5)	95.92 (5)	89.33 (5)
N_pyr1–Co–N_pyr2	82.3 (1)	107.01 (9)	98.52 (6)	98.55 (5)	106.74 (5)
N_am1–Co–N_pyr1	89.3 (1)	82.14 (9)	82.36 (6)	83.23 (5)	82.17 (4)
N_am2–Co–N_pyr2	107.0 (1)	82.51 (9)	83.28 (6)	82.39 (5)	*
N_am1–Co–O_ac1	86.9 (1)	87.36 (9)	88.81 (5)	87.96 (5)	87.84 (4)
N_pyr1–Co–O_ac1	92.8 (1)	92.34 (8)	86.51 (5)	87.72 (5)	89.92 (4)
O=C–O_ac	124.4 (2)	123.9 (3)	123.87 (14)	123.80 (14)	124.95 (10)
	124.7 (2)	124.8 (3)	123.95 (15)	123.82 (14)	*
C(O)–O_ac–Co	116.4 (1)	116.4 (2)	114.32 (9)	115.33 (10)	114.57 (7)
	115.9 (1)	115.3 (2)	115.11 (10)	114.38 (9)	*
Notes: (a) Mandel & Douglas (1989); (b) Caravan et al. (1997a); (c) two cations in asymmetric unit (McLauchlan et al., 2013); (d) this work; () N/A – symmetry equivalent; (*) N/A – sits on a special position.

Figure 2
View of the cation of the title structure, [Co(bpcd)]⁺. Here and in subsequent figures, displacement ellipsoids are shown at the 50% probability level. H atoms are shown as circles of arbitrary size. [Symmetry code: (i) −x + 1, −y + $[{1\over 2}]$ , z.]

3. Supramolecular features

The structure of the title compound (Fig. 3) exists in the solid state as an intricate network of anions and cations closely associated through many short interactions. Hydrogen-bonding interactions are listed in Table 3. Each PF₆⁻ anion is in close contact with six cations: three of the four unique F atoms interact with two neighboring cations while the remaining atom, F4, has a long interaction (2.29 Å) with only the C—H9A bond of the cyclohexyl ring of one cation. This F4⋯H9A interaction is the shortest of the F⋯H interactions present with two other weaker F⋯H interactions of 2.49 (F1⋯H10A) and 2.64 Å (F1⋯H9A) to cyclohexyl H atoms. There are also several interactions between pyrdidyl ring H atoms and carboxylate O atoms from neighboring cations, i.e. a 2.408 Å interaction with Co-bound oxygen O1, and a 2.700 Å interaction with terminal oxygen O2. The short interaction has a C—H⋯O angle of 140.7° so it does not appear in Table 3. There also exists π–π stacking for each of the two pyridyl rings with neighboring cations stacked antiparallel. Each has a distance of 3.829 (13) Å between ring centroids.

Table 3
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯O2ⁱⁱ	0.95	2.84	3.4475 (15)	122
C2—H2A⋯F3ⁱⁱⁱ	0.95	2.51	3.2928 (15)	139
C4—H4A⋯O2^iv	0.95	2.70	3.5907 (15)	157
C6—H6A⋯F2^v	0.99	2.52	3.4243 (13)	152
C6—H6B⋯F1^vi	0.99	2.74	3.3824 (13)	123
C6—H6B⋯F3^vi	0.99	2.84	3.8229 (18)	170
C7—H7A⋯F4^vii	0.99	2.68	3.3879 (13)	128
C7—H7A⋯F4^iv	0.99	2.67	3.2436 (13)	117
C7—H7B⋯F3^v	0.99	2.62	3.4982 (16)	147
C9—H9A⋯F1^vi	1.00	2.64	3.2790 (12)	122
C9—H9A⋯F4^vi	1.00	2.29	3.2336 (13)	157
C10—H10A⋯F1^vi	0.99	2.49	3.1429 (15)	123
C10—H10A⋯F2^v	0.99	2.35	3.0728 (14)	129
C10—H10B⋯F4^iv	0.99	2.77	3.5399 (14)	135
Symmetry codes: (ii) $[-x+{\script{1\over 2}}, y, -z]$ ; (iii) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (iv) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, z]$ ; (v) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (vi) $[-x+1, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (vii) $[x, -y+1, -z+{\script{1\over 2}}]$ .

Figure 3
View of the molecular components of the title structure, [Co(bpcd)]PF₆. [Symmetry code: (i) −x + 1, −y + $[{1\over 2}]$ , z.]

4. Database survey

There is very little information in the literature about H₂bpcd and its metal complexes. There is a structurally characterized heptacoordinate [Fe^II(H₂bpcd)(C₃H₆O)](ClO₄)₂ complex with trans pyridine N atoms and cis carboxylic acid groups (Oddon et al., 2012 ). In that case, Fe^II is coordinated in a distorted pentagonal–bipyramidal geometry with an unusual N₄O₃ donor atom set, including a bound acetone molecule. The carboxylic acid moieties are fully protonated with the H₂bpcd ligand coordinating through the carbonyl O atoms, which reside in the equatorial plane. The coordinating amine N atoms also lie in this plane, whereas the pyridyl N atoms are coordinating at the axial positions. This unique arrangement results in longer Fe—O and Fe—N_py bonds than are typically observed. In the present case, a fully deprotonated bpcd²⁻ ligand binds Co^III in a pseudo-octahedral fashion with trans acetate groups to form a hexacoordinate complex.

Although only one structure of a metal–H₂bpcd complex has been reported in the literature, there are several structures reported for related pseudo-octahedral Co^III complexes with bis-2-pyridylmethyl substituted diamino diacetic acids, i.e. H₂bped (A) and H₂bppd (D) in Fig. 1. We previously reported the structure of [Co(bppd)]PF₆ (McLauchlan et al., 2013 ), and there are two structural reports for the [Co(bped)]⁺ complex ion with different counter-ions, e.g. BF₄⁻ and PF₆⁻ (Mandel & Douglas, 1989 ; Caravan et al., 1997a). In these cases, the Co^III–bppd²⁻ and Co^III–bped²⁻ complexes form similar hexadentate structures with acetate O atoms in a trans orientation and pyridyl N atoms in a cis orientation.

5. Synthesis and crystallization

H₂bpcd (C) was prepared from trans-1,2-diaminocyclohexane using the procedure reported for H₂bppd (D) (Kissel et al., 2014). The title compound was prepared using methods analogous to those previously reported for [Co(bppd)]PF₆ (McLauchlan et al., 2013). Crystals suitable for diffraction were isolated by slow evaporation of a saturated acetonitrile solution (yield: 120 mg, 0.20 mmol, 40%).

Analysis observed (calculated) for CoC₂₂H₂₈N₄O₄PF₆: C 42.56 (43.00), H 3.85 (4.26), N 8.94 (9.11). IR (ν cm⁻¹, KBr): 3048 (m, C—H aryl str), 2945 (m, CH₂ str), 1665 (vs, COO⁻ str), 1612 (m, py str), 1477 (w, py str), 1445 (m, CH₂ def), 1384 (s, COO⁻ str).

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 4. The structure of the title complex can be solved and refined in Ibca with well-separated cations and anions. There is a small amount of disorder that can be modelled for the PF₆⁻ anion. F2 and F3 can be moved in the plane. R1 can be reduced to 0.0252 by modeling this disorder, but the occupancy is less than 10% and results in a less chemically satisfactory PF₆⁻ anion. Therefore, the disorder was not modelled. All H atoms were placed geometrically (C—H = 0.93–0.97 Å) and refined using a riding model.

Table 4
Experimental details

Crystal data
Chemical formula	[Co(C₂₂H₂₆N₄O₄)]PF₆
M_r	614.37
Crystal system, space group	Orthorhombic, Ibca
Temperature (K)	100
a, b, c (Å)	13.9848 (4), 14.6221 (4), 22.2177 (6)
V (Å³)	4543.2 (2)
Z	8
Radiation type	Mo Kα
μ (mm⁻¹)	0.92
Crystal size (mm)	0.44 × 0.36 × 0.21

Data collection
Diffractometer	Bruker APEXII equipped with a CCD detector
Absorption correction	Multi-scan (SADABS; Bruker, 2008 )
T_min, T_max	0.691, 0.834
No. of measured, independent and observed [I > 2σ(I)] reflections	57644, 3630, 3401
R_int	0.017
(sin θ/λ)_max (Å⁻¹)	0.725

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.027, 0.079, 1.12
No. of reflections	3630
No. of parameters	174
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.66, −0.52
Computer programs: APEX2 and SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), ORTEP-3 for Windows (Farrugia, 2012 ), enCIFer (Allen et al., 2004 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1053810

Crystal structure: contains datablock I. DOI: 10.1107/S2056989015005149/zl2616sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2056989015005149/zl2616Isup2.hkl

Supporting information file. DOI: 10.1107/S2056989015005149/zl2616Isup3.cdx

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: enCIFer (Allen et al., 2004) and publCIF (Westrip, 2010).

{2,2'-[N,N'-Bis(pyridin-2-ylmethyl)cyclohexane-trans-1,2-diyldi(nitrilo)]diacetato}cobalt(III) hexafluoridophosphate top

Crystal data top

[Co(C₂₂H₂₆N₄O₄)]PF₆	D_x = 1.796 Mg m⁻³
M_r = 614.37	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Ibca	Cell parameters from 9742 reflections
a = 13.9848 (4) Å	θ = 2.7–31.0°
b = 14.6221 (4) Å	µ = 0.92 mm⁻¹
c = 22.2177 (6) Å	T = 100 K
V = 4543.2 (2) Å³	Parallelipiped, translucent dark red
Z = 8	0.44 × 0.36 × 0.21 mm
F(000) = 2512

Data collection top

Bruker APEXII diffractometer equipped with a CCD detector	3630 independent reflections
Radiation source: fine-focus sealed tube	3401 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.017
Detector resolution: 8.3333 pixels mm^-1	θ_max = 31.0°, θ_min = 1.8°
φ and ω scans	h = −20→20
Absorption correction: multi-scan (SADABS; Bruker, 2008)	k = −21→21
T_min = 0.691, T_max = 0.834	l = −32→32
57644 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.027	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.079	H-atom parameters constrained
S = 1.12	w = 1/[σ²(F_o²) + (0.0415P)² + 5.6191P] where P = (F_o² + 2F_c²)/3
3630 reflections	(Δ/σ)_max = 0.001
174 parameters	Δρ_max = 0.66 e Å⁻³
0 restraints	Δρ_min = −0.52 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.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. There is a small amount of disorder that can be modeled for the PF₆ anion. F2 and F3 can be moved in the plane, as one might imagine. R1 can be reduced to 0.0252 by modeling it, but the occupancy is less than 10% and results in a less chemically satisfactory PF₆ anion. Therefore, the disorder was not modeled.

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

	x	y	z	U_iso*/U_eq
Co1	0.5000	0.2500	0.09254 (2)	0.00761 (6)
N1	0.43958 (7)	0.15960 (6)	0.04005 (4)	0.01066 (16)
N2	0.43848 (6)	0.17734 (6)	0.15480 (4)	0.00930 (16)
O1	0.38813 (6)	0.32200 (5)	0.08964 (3)	0.01162 (15)
O2	0.23055 (6)	0.30823 (7)	0.10495 (4)	0.01942 (18)
C1	0.41181 (8)	0.16885 (8)	−0.01758 (5)	0.01342 (19)
H1A	0.4189	0.2265	−0.0369	0.016*
C2	0.37301 (8)	0.09611 (8)	−0.04959 (5)	0.0159 (2)
H2A	0.3555	0.1035	−0.0906	0.019*
C3	0.36018 (8)	0.01258 (8)	−0.02102 (6)	0.0160 (2)
H3A	0.3356	−0.0384	−0.0426	0.019*
C4	0.38383 (8)	0.00449 (8)	0.03974 (5)	0.0145 (2)
H4A	0.3729	−0.0511	0.0607	0.017*
C5	0.42361 (7)	0.07927 (7)	0.06891 (5)	0.01135 (18)
C6	0.44904 (8)	0.08027 (7)	0.13472 (5)	0.01223 (18)
H6A	0.4055	0.0399	0.1577	0.015*
H6B	0.5156	0.0590	0.1408	0.015*
C7	0.33453 (7)	0.20455 (8)	0.15563 (5)	0.01188 (19)
H7A	0.3164	0.2220	0.1971	0.014*
H7B	0.2951	0.1513	0.1439	0.014*
C8	0.31295 (8)	0.28378 (8)	0.11346 (5)	0.01202 (18)
C9	0.49132 (7)	0.19846 (8)	0.21257 (5)	0.01084 (18)
H9A	0.5551	0.1678	0.2102	0.013*
C10	0.44229 (8)	0.16490 (8)	0.27004 (5)	0.0154 (2)
H10A	0.4399	0.0972	0.2700	0.019*
H10B	0.3758	0.1882	0.2714	0.019*
C11	0.49688 (8)	0.19815 (10)	0.32563 (5)	0.0182 (2)
H11A	0.4637	0.1772	0.3625	0.022*
H11B	0.5621	0.1718	0.3256	0.022*
P1	0.30339 (3)	0.5000	0.2500	0.01160 (8)
F1	0.41712 (9)	0.5000	0.2500	0.0503 (5)
F2	0.19013 (9)	0.5000	0.2500	0.0417 (4)
F3	0.30336 (11)	0.49194 (7)	0.32124 (4)	0.0470 (3)
F4	0.30308 (5)	0.60985 (5)	0.25526 (4)	0.01831 (15)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Co1	0.00914 (10)	0.00719 (10)	0.00650 (10)	−0.00083 (6)	0.000	0.000
N1	0.0118 (4)	0.0103 (4)	0.0099 (4)	−0.0015 (3)	−0.0002 (3)	−0.0010 (3)
N2	0.0103 (4)	0.0095 (4)	0.0081 (4)	−0.0005 (3)	0.0000 (3)	0.0010 (3)
O1	0.0113 (3)	0.0106 (3)	0.0130 (3)	0.0008 (3)	−0.0004 (3)	0.0018 (3)
O2	0.0119 (4)	0.0223 (4)	0.0241 (4)	0.0033 (3)	−0.0017 (3)	0.0040 (3)
C1	0.0140 (4)	0.0167 (5)	0.0095 (4)	−0.0025 (4)	0.0000 (3)	−0.0006 (3)
C2	0.0133 (5)	0.0222 (5)	0.0123 (4)	−0.0031 (4)	0.0001 (4)	−0.0053 (4)
C3	0.0117 (4)	0.0167 (5)	0.0198 (5)	−0.0014 (4)	0.0007 (4)	−0.0087 (4)
C4	0.0129 (4)	0.0105 (4)	0.0200 (5)	−0.0008 (3)	0.0003 (4)	−0.0036 (4)
C5	0.0111 (4)	0.0100 (4)	0.0129 (4)	−0.0007 (3)	0.0004 (3)	−0.0008 (3)
C6	0.0156 (4)	0.0087 (4)	0.0124 (4)	−0.0011 (3)	−0.0010 (4)	0.0014 (3)
C7	0.0095 (4)	0.0143 (5)	0.0118 (4)	−0.0003 (3)	0.0000 (3)	0.0026 (3)
C8	0.0125 (4)	0.0125 (4)	0.0111 (4)	0.0001 (4)	−0.0010 (3)	−0.0002 (3)
C9	0.0115 (4)	0.0133 (5)	0.0077 (4)	−0.0004 (3)	−0.0007 (3)	0.0013 (3)
C10	0.0163 (5)	0.0208 (5)	0.0092 (4)	−0.0020 (4)	0.0011 (4)	0.0037 (4)
C11	0.0182 (5)	0.0277 (6)	0.0087 (4)	0.0011 (4)	−0.0006 (4)	0.0031 (4)
P1	0.01124 (17)	0.01151 (17)	0.01203 (17)	0.000	0.000	0.00031 (13)
F1	0.0127 (5)	0.0204 (6)	0.1178 (16)	0.000	0.000	−0.0134 (8)
F2	0.0128 (5)	0.0206 (6)	0.0916 (13)	0.000	0.000	−0.0056 (7)
F3	0.1008 (10)	0.0246 (5)	0.0157 (4)	0.0046 (5)	−0.0073 (5)	−0.0001 (3)
F4	0.0176 (3)	0.0116 (3)	0.0258 (4)	0.0001 (2)	−0.0029 (3)	−0.0010 (3)

Geometric parameters (Å, º) top

Co1—O1ⁱ	1.8869 (8)	C5—C6	1.5050 (15)
Co1—O1	1.8869 (8)	C6—H6A	0.9900
Co1—N1	1.9548 (9)	C6—H6B	0.9900
Co1—N1ⁱ	1.9548 (9)	C7—C8	1.5201 (15)
Co1—N2	1.9448 (9)	C7—H7A	0.9900
Co1—N2ⁱ	1.9449 (9)	C7—H7B	0.9900
N1—C1	1.3448 (14)	C9—C9ⁱ	1.527 (2)
N1—C5	1.3567 (14)	C9—C10	1.5300 (15)
N2—C6	1.4951 (14)	C9—H9A	1.0000
N2—C7	1.5073 (14)	C10—C11	1.5312 (16)
N2—C9	1.5130 (13)	C10—H10A	0.9900
O1—C8	1.3029 (13)	C10—H10B	0.9900
O2—C8	1.2212 (14)	C11—C11ⁱ	1.519 (3)
C1—C2	1.3898 (15)	C11—H11A	0.9900
C1—H1A	0.9500	C11—H11B	0.9900
C2—C3	1.3882 (17)	P1—F2	1.5840 (13)
C2—H2A	0.9500	P1—F3	1.5872 (9)
C3—C4	1.3949 (17)	P1—F3ⁱⁱ	1.5873 (9)
C3—H3A	0.9500	P1—F1	1.5905 (14)
C4—C5	1.3873 (15)	P1—F4	1.6106 (7)
C4—H4A	0.9500	P1—F4ⁱⁱ	1.6106 (7)

O1ⁱ—Co1—O1	176.08 (5)	C5—C6—H6B	110.5
O1ⁱ—Co1—N2	94.95 (4)	H6A—C6—H6B	108.7
O1—Co1—N2	87.84 (4)	N2—C7—C8	112.65 (8)
O1ⁱ—Co1—N2ⁱ	87.84 (4)	N2—C7—H7A	109.1
O1—Co1—N2ⁱ	94.95 (4)	C8—C7—H7A	109.1
N2—Co1—N2ⁱ	89.33 (5)	N2—C7—H7B	109.1
O1ⁱ—Co1—N1	87.75 (4)	C8—C7—H7B	109.1
O1—Co1—N1	89.92 (4)	H7A—C7—H7B	107.8
N2—Co1—N1	82.17 (4)	O2—C8—O1	124.95 (10)
N2ⁱ—Co1—N1	170.04 (4)	O2—C8—C7	120.39 (10)
O1ⁱ—Co1—N1ⁱ	89.92 (4)	O1—C8—C7	114.65 (9)
O1—Co1—N1ⁱ	87.75 (4)	N2—C9—C9ⁱ	106.21 (7)
N2—Co1—N1ⁱ	170.04 (4)	N2—C9—C10	115.07 (9)
N2ⁱ—Co1—N1ⁱ	82.17 (4)	C9ⁱ—C9—C10	112.82 (7)
N1—Co1—N1ⁱ	106.74 (5)	N2—C9—H9A	107.5
C1—N1—C5	119.30 (9)	C9ⁱ—C9—H9A	107.5
C1—N1—Co1	128.67 (8)	C10—C9—H9A	107.5
C5—N1—Co1	112.01 (7)	C9—C10—C11	110.36 (9)
C6—N2—C7	110.46 (8)	C9—C10—H10A	109.6
C6—N2—C9	113.49 (8)	C11—C10—H10A	109.6
C7—N2—C9	114.01 (8)	C9—C10—H10B	109.6
C6—N2—Co1	105.23 (6)	C11—C10—H10B	109.6
C7—N2—Co1	106.93 (6)	H10A—C10—H10B	108.1
C9—N2—Co1	106.01 (6)	C11ⁱ—C11—C10	110.22 (9)
C8—O1—Co1	114.57 (7)	C11ⁱ—C11—H11A	109.6
N1—C1—C2	121.54 (10)	C10—C11—H11A	109.6
N1—C1—H1A	119.2	C11ⁱ—C11—H11B	109.6
C2—C1—H1A	119.2	C10—C11—H11B	109.6
C3—C2—C1	119.32 (10)	H11A—C11—H11B	108.1
C3—C2—H2A	120.3	F2—P1—F3	89.98 (6)
C1—C2—H2A	120.3	F2—P1—F3ⁱⁱ	89.98 (6)
C2—C3—C4	119.11 (10)	F3—P1—F3ⁱⁱ	179.97 (11)
C2—C3—H3A	120.4	F2—P1—F1	180.0
C4—C3—H3A	120.4	F3—P1—F1	90.02 (6)
C5—C4—C3	118.70 (11)	F3ⁱⁱ—P1—F1	90.02 (6)
C5—C4—H4A	120.6	F2—P1—F4	89.84 (3)
C3—C4—H4A	120.6	F3—P1—F4	90.09 (5)
N1—C5—C4	121.85 (10)	F3ⁱⁱ—P1—F4	89.91 (5)
N1—C5—C6	114.31 (9)	F1—P1—F4	90.16 (3)
C4—C5—C6	123.80 (10)	F2—P1—F4ⁱⁱ	89.84 (3)
N2—C6—C5	106.01 (8)	F3—P1—F4ⁱⁱ	89.91 (5)
N2—C6—H6A	110.5	F3ⁱⁱ—P1—F4ⁱⁱ	90.09 (5)
C5—C6—H6A	110.5	F1—P1—F4ⁱⁱ	90.16 (3)
N2—C6—H6B	110.5	F4—P1—F4ⁱⁱ	179.69 (6)

N2—Co1—O1—C8	−17.97 (8)	N1—C5—C6—N2	27.33 (12)
N2ⁱ—Co1—O1—C8	−107.11 (8)	C4—C5—C6—N2	−150.39 (10)
N1—Co1—O1—C8	64.20 (8)	C6—N2—C7—C8	−119.41 (9)
N1ⁱ—Co1—O1—C8	170.96 (8)	C9—N2—C7—C8	111.40 (10)
C5—N1—C1—C2	−4.46 (16)	Co1—N2—C7—C8	−5.42 (10)
Co1—N1—C1—C2	177.37 (8)	Co1—O1—C8—O2	−162.99 (10)
N1—C1—C2—C3	1.77 (17)	Co1—O1—C8—C7	18.41 (12)
C1—C2—C3—C4	1.97 (17)	N2—C7—C8—O2	173.28 (10)
C2—C3—C4—C5	−2.94 (16)	N2—C7—C8—O1	−8.05 (13)
C1—N1—C5—C4	3.43 (16)	C6—N2—C9—C9ⁱ	156.93 (9)
Co1—N1—C5—C4	−178.11 (8)	C7—N2—C9—C9ⁱ	−75.42 (11)
C1—N1—C5—C6	−174.34 (9)	Co1—N2—C9—C9ⁱ	41.93 (10)
Co1—N1—C5—C6	4.12 (11)	C6—N2—C9—C10	−77.49 (11)
C3—C4—C5—N1	0.28 (16)	C7—N2—C9—C10	50.16 (12)
C3—C4—C5—C6	177.83 (10)	Co1—N2—C9—C10	167.51 (8)
C7—N2—C6—C5	69.87 (10)	N2—C9—C10—C11	−174.45 (9)
C9—N2—C6—C5	−160.66 (8)	C9ⁱ—C9—C10—C11	−52.36 (14)
Co1—N2—C6—C5	−45.20 (9)	C9—C10—C11—C11ⁱ	58.00 (14)

Symmetry codes: (i) −x+1, −y+1/2, z; (ii) x, −y+1, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···O2ⁱⁱⁱ	0.95	2.84	3.4475 (15)	122
C2—H2A···F3^iv	0.95	2.51	3.2928 (15)	139
C4—H4A···O2^v	0.95	2.70	3.5907 (15)	157
C6—H6A···F2^vi	0.99	2.52	3.4243 (13)	152
C6—H6B···F1^vii	0.99	2.74	3.3824 (13)	123
C6—H6B···F3^vii	0.99	2.84	3.8229 (18)	170
C7—H7A···F4ⁱⁱ	0.99	2.68	3.3879 (13)	128
C7—H7A···F4^v	0.99	2.67	3.2436 (13)	117
C7—H7B···F3^vi	0.99	2.62	3.4982 (16)	147
C9—H9A···F1^vii	1.00	2.64	3.2790 (12)	122
C9—H9A···F4^vii	1.00	2.29	3.2336 (13)	157
C10—H10A···F1^vii	0.99	2.49	3.1429 (15)	123
C10—H10A···F2^vi	0.99	2.35	3.0728 (14)	129
C10—H10B···F4^v	0.99	2.77	3.5399 (14)	135

Symmetry codes: (ii) x, −y+1, −z+1/2; (iii) −x+1/2, y, −z; (iv) x, −y+1/2, z−1/2; (v) −x+1/2, y−1/2, z; (vi) −x+1/2, −y+1/2, −z+1/2; (vii) −x+1, y−1/2, −z+1/2.

Bond distances (Å) and experimental data for different [Co(bpad)]⁺ structures. top

Bond (Å)	Co(bped)^{+ a}	Co(bped)^{+ b}	Co(bppd)^{+ c} 1	Co(bppd)^{+ c} 2	Co(bpcd)^{+ d}
Co–O_ac1	1.888 (1)	1.878 (2)	1.8828 (11)	1.8875 (10)	1.8869 (8)
Co–O_ac2	1.889 (2)	1.888 (2)	1.8899 (11)	1.8830 (11)	*
Co–N_am1	1.941 (2)	1.937 (2)	1.9625 (13)	1.9654 (12)	1.9548 (9)
Co–N_am2	1.974 (2)	1.941 (2)	1.9641 (13)	1.9645 (12)	*
Co–N_pyr1	1.944 (2)	1.960 (2)	1.9484 (13)	1.9403 (13)	1.9448 (9)
Co–N_pyr2	1.954 (2)	1.958 (2)	1.9397 (13)	1.9576 (13)	*
C–O_ac1	1.294 (2)	1.298 (4)	1.2973 (18)	1.3054 (18)	1.3029 (13)
C═O_ac1	1.212 (3)	1.218 (3)	1.2265 (18)	1.219 (2)	1.2212 (14)
C–O_ac2	1.289 (3)	1.299 (3)	1.3035 (19)	1.2971 (19)	*
C═O_ac2	1.210 (3)	1.213 (3)	1.2201 (19)	0.0030 (6)	*
Co above N/N/N/N plane	0.000^†	0.012^†	0.0026 (6)	0.0030 (6)	0**
Temp, K	298	293	100	100	100

Notes: (a) Mandel & Douglas (1989); (b) Caravan et al. (1997a); (c) two cations in asymmetric unit (McLauchlan et al., 2013); (d) this work; (*) N/A – symmetry equivalent; (†) error unavailable; (**) N/A – sits on a special position.

Selected bond angles (°) for different [Co(bpad)]⁺ structures. top

Angle, °	Co(bped)^{+ a}	Co(bped)^{+ b}	Co(bppd)^{+ c} 1	Co(bppd)^{+ c} 2	Co(bpcd)^{+ d}
O_ac1–Co–O_ac2	178.8 (1)	178.53 (8)	178.47 (5)	178.36 (5)	176.08 (5)
N_am1–Co–N_am2	82.0 (1)	88.87 (9)	95.91 (5)	95.92 (5)	89.33 (5)
N_pyr1–Co–N_pyr2	82.3 (1)	107.01 (9)	98.52 (6)	98.55 (5)	106.74 (5)
N_am1–Co–N_pyr1	89.3 (1)	82.14 (9)	82.36 (6)	83.23 (5)	82.17 (4)
N_am2–Co–N_pyr2	107.0 (1)	82.51 (9)	83.28 (6)	82.39 (5)	*
N_am1–Co–O_ac1	86.9 (1)	87.36 (9)	88.81 (5)	87.96 (5)	87.84 (4)
N_pyr1–Co–O_ac1	92.8 (1)	92.34 (8)	86.51 (5)	87.72 (5)	89.92 (4)
O═C–O_ac	124.4 (2)	123.9 (3)	123.87 (14)	123.80 (14)	124.95 (10)
	124.7 (2)	124.8 (3)	123.95 (15)	123.82 (14)	*
C(O)–O_ac–Co	116.4 (1)	116.4 (2)	114.32 (9)	115.33 (10)	114.57 (7)
	115.9 (1)	115.3 (2)	115.11 (10)	114.38 (9)	*

Notes: (a) Mandel & Douglas (1989); (b) Caravan et al. (1997a); (c) two cations in asymmetric unit (McLauchlan et al., 2013); (d) this work; (*) N/A – symmetry equivalent; (**) N/A – sits on a special position.

Footnotes

‡Current address: Department of Chemistry, Lewis University, Romeoville, IL 60446, USA.

Acknowledgements

This work was supported by Illinois State University and Loyola University Chicago. CCM acknowledges the National Science Foundation for the purchase of the Bruker APEXII diffractometer (CHE-10-39689). DSK wishes to thank Loyola University Chicago and the Schmitt Foundation for fifth year fellowship support.

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