research communications
Structure of Λ(δλλ)-[Co(en)3]I3(I)2
aUniversity of Notre Dame, Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, Notre Dame IN 46556, USA
*Correspondence e-mail: alappin1@nd.edu
The structure of tris(ethane-1,2-diamine-κ2N,N')cobalt(III) bis(iodide) triiodide, [Co(C2H8N2)3]I3(I)2, at 120 K has orthorhombic (P212121) symmetry. The diamine nitrogen atoms form N—H⋯I hydrogen bonds throughout the lattice, resulting in a three-dimensional network, which involves the iodide and all atoms in the triiodide anions.
Keywords: crystal structure; cobalt coordination; chiral coordination.
CCDC reference: 2070495
1. Chemical context
Significant information on the hydrogen bonding and other interactions that contribute to the chiral discriminations between metal-ion complexes has been obtained from the crystal structures of compounds containing a chiral complex cation and a chiral complex anion (Warren et al., 1994; Marusak & Lappin, 1989). For example, a comparison of the compounds Λ-[Co(en)3]Δ-[Co(en)(ox)2]I2·3H2O and Δ-[Co(en)3]Δ-[Co(en)(ox)2]I2·H2O reveals the importance of different helicities projected along the C3 and C2 axes of [Co(en)3]3+ in discriminating with the pseudo-C3 face of the Δ-[Co(en)(ox)2]− anion (Lappin et al., 1993).
As part of a study involving potential effects of non-chiral counter-ions, an attempt was made to grow crystals with [Co(en)3]I3 and Na[Co(edta)]. However, in the presence of I−, the mildly oxidizing [Co(edta)]− was reduced and an unexpected product, [Co(en)3]I3(I)2 was obtained. The structure of the corresponding cobalt(II) complex, [Co(en)3]I3I, has been reported (Du et al., 2007). The larger cobalt(II) complex supports an lel3 geometry of the bidentate ligands around the cobalt center. The Co—N bond distances in [Co(en)3]2+ average 2.28 Å, significantly longer than the 1.97 Å average in [Co(en)3]3+ and consistent with the sluggish redox exchange between the complexes (Jolley et al., 1990). In [Co(en)3]I3I, the I− ions are located along the quasi-C2 axis of the [Co(en)3]2+ complex ion with close hydrogen-bond contacts from N—H protons of 2.91 Å. The terminal iodine atoms of the I3− ions likewise form hydrogen bonds with N—H protons at 2.93 Å, resulting in an alternating chain of linear I3− ions at 90° to one another down the c-axis direction.
2. Structural commentary
The complex, [Co(en)3](I3)(I)2 crystallizes as dark-red, rod-like crystals. The of the primitive, acentric, orthorhombic P212121 consists of one [Co(en)3]3+ cation, two iodide anions and a triiodide anion (Fig. 1). The correct enantiomorph of the was determined by comparison of intensities of Friedel pairs of reflections, yielding a Flack x parameter of 0.017 (9) (Parsons et al., 2013) and a Hooft y parameter of 0.006 (8) (Hooft et al., 2008). Values close to zero indicate the correct enantiomorph of the This determination allows an accurate assessment of the configuration of the cobalt cation.
The cobalt center is located in a slightly distorted octahedral environment by the nitrogen atoms of three ethylene diamine ligands (see Table 1 for details). The ligands adopt a Λ(δλλ) lel ob ob (lelob2) geometry about the cobalt center, Fig. 1. Bond distances and angles within the molecules are unexceptional.
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The amine hydrogen atoms were initially located from a difference-Fourier map and were refined freely. All of the amine hydrogen atoms are involved in hydrogen bonds to nearby iodine/triiodide moieties, Fig. 2. This interconnectivity results in a three-dimensional hydrogen-bonded network throughout the entire structure.
3. Supramolecular features
The iodide ion I−(1) is hydrogen bonded to N—H protons from N4 on one [Co(en)3]3+ ion at 2.77 Å, bridging to N—H protons on N4 and N5 from the two ligands with a λ-configuration on an adjacent cation with distances of 2.90 (5) and 2.95 (5) Å (Fig. 2, Table 2). The pairwise interactions create a hydrogen-bonded chain along the crystallographic a-axis direction, forming a layer with the complex cations separated by channels formed by I3− ions in an alternating herringbone pattern punctuated by I2− ions. The iodide I2− forms a hydrogen-bonded network bridging the layers with N—H protons from three separate cations at 2.79 (5), 2.80 (5) and 2.83 (5) Å. The I3− ion has a close N—H contact with N6 at 2.89 (5) Å.
4. Database survey
A survey of Co(en)3 coupled with iodine reveals 23 structures in the Cambridge Structural Database (CSD v5.42, November 2020; Groom et al., 2016). Predominantly these are Co(III) complexes. There are three reports of Co(en)3I3 (EDANEC, Matsuki et al., 2001; ENCOIH, Whuler et al., 1980; FIXLAI, Grant et al., 2019). EDANEC and FIXLAI are structural analyses of the Λ- and Δ-isomers, respectively. The by Whuler et al. is of the racemic cation species. A mixed Cl/I species was reported by Huang and co-workers (FAXMEX, Zhang et al., 2005). All of these reports also contain water of crystallization. There is one report of Co(en)3 that has both an iodide and a triodide pair of counter-ions that crystallizes in the tetragonal I2d (HIQYUC, Du et al., 2007). However, that report is of the CoII complex, Co(en)3(I3)I.
5. Synthesis and crystallization
Crystals were obtained from an attempt to co-crystallize optically active [Co(en)3]3+ and the mildly oxidizing [Co(edta)]− from Λ-[Co(en)3]I3 and Na[Co(edta)]. After storage at 283 K for two weeks, the deep-purple coloration of the [Co(edta)]− ion had disappeared and dark-red well-formed crystals were recovered.
6. Refinement
Crystal data, data collection and structure . The structure was solved by dual-space methods (Sheldrick, 2015a) and refined routinely (Sheldrick, 2015b). Amine hydrogen atoms were refined freely and methylene hydrogen atoms were refined as riding on the carbon to which they are bonded with C—H = 0.99 Å and Uiso(H) = 1.2Ueq(C).
details are summarized in Table 3
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Supporting information
CCDC reference: 2070495
https://doi.org/10.1107/S2056989021002826/dj2023sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989021002826/dj2023Isup2.hkl
Data collection: APEX3 (Bruker, 2015); cell
SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SHELXT2014/5 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2020); software used to prepare material for publication: CIFTAB (Sheldrick, 2008) and publCIF (Westrip, 2010).[Co(C2H8N2)3]I3(I)2 | Dx = 2.890 Mg m−3 |
Mr = 873.74 | Mo Kα radiation, λ = 0.71073 Å |
Orthorhombic, P212121 | Cell parameters from 9680 reflections |
a = 8.7508 (12) Å | θ = 2.4–28.4° |
b = 8.8333 (12) Å | µ = 8.54 mm−1 |
c = 25.982 (4) Å | T = 120 K |
V = 2008.4 (5) Å3 | Rod, dark red |
Z = 4 | 0.28 × 0.15 × 0.10 mm |
F(000) = 1576 |
Bruker Kappa X8 APEXII diffractometer | 5024 independent reflections |
Radiation source: fine-focus sealed tube | 5023 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.022 |
Detector resolution: 8.33 pixels mm-1 | θmax = 28.3°, θmin = 1.6° |
combination of ω and φ–scans | h = −11→11 |
Absorption correction: numerical (SADABS; Krause et al., 2015) | k = −11→11 |
Tmin = 0.603, Tmax = 1.000 | l = −33→34 |
35617 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.012 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.028 | w = 1/[σ2(Fo2) + (0.0073P)2 + 1.9769P] where P = (Fo2 + 2Fc2)/3 |
S = 1.33 | (Δ/σ)max = 0.001 |
5024 reflections | Δρmax = 0.39 e Å−3 |
199 parameters | Δρmin = −0.66 e Å−3 |
0 restraints | Absolute structure: Flack x determined using 2136 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013) |
Primary atom site location: dual | Absolute structure parameter: 0.017 (9) |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
x | y | z | Uiso*/Ueq | ||
I1 | 0.32971 (3) | 0.22384 (3) | 0.55282 (2) | 0.01429 (5) | |
I2 | 0.69407 (3) | 0.30959 (2) | 0.22059 (2) | 0.01325 (5) | |
I3 | −0.13267 (3) | 0.17300 (3) | 0.01437 (2) | 0.01367 (5) | |
I4 | 0.05242 (3) | 0.28734 (2) | 0.09775 (2) | 0.01107 (5) | |
I5 | 0.22245 (3) | 0.40722 (3) | 0.18675 (2) | 0.01307 (5) | |
Co1 | 0.32630 (5) | 0.30665 (5) | 0.36719 (2) | 0.00693 (8) | |
N1 | 0.4364 (4) | 0.4391 (3) | 0.31911 (13) | 0.0111 (6) | |
H1C | 0.466 (6) | 0.383 (5) | 0.2936 (18) | 0.013* | |
H1D | 0.380 (6) | 0.513 (5) | 0.3077 (18) | 0.013* | |
N2 | 0.4337 (4) | 0.4219 (4) | 0.42174 (12) | 0.0119 (6) | |
H2C | 0.374 (6) | 0.453 (5) | 0.4473 (19) | 0.014* | |
H2D | 0.500 (6) | 0.370 (5) | 0.4332 (19) | 0.014* | |
N3 | 0.4917 (4) | 0.1557 (3) | 0.36466 (13) | 0.0121 (6) | |
H3C | 0.484 (6) | 0.087 (5) | 0.3358 (18) | 0.015* | |
H3D | 0.571 (6) | 0.189 (6) | 0.3664 (19) | 0.015* | |
N4 | 0.2318 (4) | 0.1713 (4) | 0.41825 (12) | 0.0122 (6) | |
H4C | 0.248 (5) | 0.217 (5) | 0.4497 (19) | 0.015* | |
H4D | 0.129 (6) | 0.168 (5) | 0.4168 (18) | 0.015* | |
N5 | 0.1500 (4) | 0.4446 (3) | 0.36922 (12) | 0.0114 (6) | |
H5C | 0.094 (6) | 0.419 (5) | 0.3963 (19) | 0.014* | |
H5D | 0.173 (6) | 0.543 (5) | 0.3687 (18) | 0.014* | |
N6 | 0.2158 (4) | 0.2066 (3) | 0.31060 (12) | 0.0109 (5) | |
H6C | 0.261 (5) | 0.236 (5) | 0.2807 (19) | 0.013* | |
H6D | 0.227 (5) | 0.100 (5) | 0.3128 (18) | 0.013* | |
C1 | 0.5641 (4) | 0.5172 (4) | 0.34653 (16) | 0.0154 (7) | |
H1A | 0.595861 | 0.608878 | 0.327383 | 0.018* | |
H1B | 0.653317 | 0.448913 | 0.349678 | 0.018* | |
C2 | 0.5050 (5) | 0.5596 (4) | 0.39899 (16) | 0.0158 (7) | |
H2A | 0.589927 | 0.595429 | 0.421034 | 0.019* | |
H2B | 0.428560 | 0.641804 | 0.396078 | 0.019* | |
C3 | 0.4761 (4) | 0.0485 (4) | 0.40885 (15) | 0.0129 (7) | |
H3A | 0.521899 | 0.092664 | 0.440276 | 0.016* | |
H3B | 0.528980 | −0.047957 | 0.401093 | 0.016* | |
C4 | 0.3078 (5) | 0.0210 (4) | 0.41678 (15) | 0.0146 (7) | |
H4A | 0.266124 | −0.040706 | 0.388242 | 0.018* | |
H4B | 0.290451 | −0.033783 | 0.449508 | 0.018* | |
C5 | 0.0500 (4) | 0.4213 (4) | 0.32313 (15) | 0.0135 (7) | |
H5A | 0.089273 | 0.479960 | 0.293487 | 0.016* | |
H5B | −0.055557 | 0.455093 | 0.330595 | 0.016* | |
C6 | 0.0521 (4) | 0.2540 (4) | 0.31111 (15) | 0.0135 (7) | |
H6A | −0.005054 | 0.196883 | 0.337647 | 0.016* | |
H6B | 0.004415 | 0.234598 | 0.277189 | 0.016* |
U11 | U22 | U33 | U12 | U13 | U23 | |
I1 | 0.00933 (10) | 0.02215 (11) | 0.01140 (10) | 0.00063 (9) | −0.00073 (9) | −0.00018 (9) |
I2 | 0.01308 (11) | 0.01112 (9) | 0.01555 (11) | −0.00011 (8) | −0.00068 (9) | −0.00056 (8) |
I3 | 0.01745 (12) | 0.01416 (10) | 0.00939 (10) | 0.00078 (8) | 0.00012 (9) | −0.00136 (8) |
I4 | 0.01061 (10) | 0.01122 (9) | 0.01138 (10) | 0.00010 (8) | 0.00211 (8) | 0.00068 (8) |
I5 | 0.01294 (11) | 0.01450 (10) | 0.01176 (11) | −0.00060 (8) | −0.00106 (9) | 0.00081 (8) |
Co1 | 0.0067 (2) | 0.00784 (19) | 0.00628 (19) | −0.00032 (16) | 0.00029 (17) | 0.00003 (15) |
N1 | 0.0095 (14) | 0.0099 (13) | 0.0139 (15) | −0.0003 (11) | 0.0011 (13) | 0.0024 (11) |
N2 | 0.0109 (15) | 0.0144 (14) | 0.0104 (14) | −0.0011 (12) | −0.0008 (12) | −0.0011 (11) |
N3 | 0.0116 (15) | 0.0110 (13) | 0.0138 (15) | 0.0019 (11) | 0.0024 (13) | 0.0024 (11) |
N4 | 0.0083 (14) | 0.0189 (14) | 0.0095 (14) | −0.0023 (12) | 0.0009 (12) | 0.0023 (12) |
N5 | 0.0108 (15) | 0.0130 (14) | 0.0104 (14) | 0.0028 (11) | −0.0015 (12) | −0.0024 (11) |
N6 | 0.0156 (14) | 0.0080 (12) | 0.0091 (13) | 0.0005 (11) | −0.0008 (12) | −0.0004 (10) |
C1 | 0.0100 (17) | 0.0149 (16) | 0.0212 (19) | −0.0073 (14) | −0.0008 (16) | 0.0043 (14) |
C2 | 0.0150 (18) | 0.0125 (16) | 0.020 (2) | −0.0049 (14) | −0.0044 (16) | −0.0013 (14) |
C3 | 0.0147 (18) | 0.0117 (15) | 0.0124 (17) | 0.0021 (13) | 0.0000 (14) | 0.0048 (13) |
C4 | 0.0187 (19) | 0.0112 (14) | 0.0140 (17) | −0.0041 (14) | −0.0003 (15) | 0.0048 (12) |
C5 | 0.0103 (16) | 0.0175 (16) | 0.0127 (17) | 0.0016 (13) | −0.0033 (14) | −0.0019 (13) |
C6 | 0.0100 (16) | 0.0178 (16) | 0.0126 (16) | −0.0042 (13) | −0.0018 (14) | −0.0011 (13) |
I3—I4 | 2.8875 (4) | N5—H5C | 0.89 (5) |
I4—I5 | 2.9464 (4) | N5—H5D | 0.89 (5) |
Co1—N1 | 1.964 (3) | N6—C6 | 1.493 (5) |
Co1—N5 | 1.967 (3) | N6—H6C | 0.91 (5) |
Co1—N4 | 1.968 (3) | N6—H6D | 0.95 (5) |
Co1—N3 | 1.968 (3) | C1—C2 | 1.505 (6) |
Co1—N6 | 1.969 (3) | C1—H1A | 0.9900 |
Co1—N2 | 1.982 (3) | C1—H1B | 0.9900 |
N1—C1 | 1.494 (5) | C2—H2A | 0.9900 |
N1—H1C | 0.87 (5) | C2—H2B | 0.9900 |
N1—H1D | 0.87 (5) | C3—C4 | 1.507 (5) |
N2—C2 | 1.490 (5) | C3—H3A | 0.9900 |
N2—H2C | 0.89 (5) | C3—H3B | 0.9900 |
N2—H2D | 0.80 (5) | C4—H4A | 0.9900 |
N3—C3 | 1.495 (5) | C4—H4B | 0.9900 |
N3—H3C | 0.97 (5) | C5—C6 | 1.511 (5) |
N3—H3D | 0.76 (5) | C5—H5A | 0.9900 |
N4—C4 | 1.486 (5) | C5—H5B | 0.9900 |
N4—H4C | 0.92 (5) | C6—H6A | 0.9900 |
N4—H4D | 0.90 (5) | C6—H6B | 0.9900 |
N5—C5 | 1.498 (5) | ||
I3—I4—I5 | 176.193 (11) | Co1—N5—H5D | 115 (3) |
N1—Co1—N5 | 91.86 (14) | H5C—N5—H5D | 113 (4) |
N1—Co1—N4 | 175.38 (14) | C6—N6—Co1 | 109.8 (2) |
N5—Co1—N4 | 91.64 (14) | C6—N6—H6C | 110 (3) |
N1—Co1—N3 | 91.25 (13) | Co1—N6—H6C | 107 (3) |
N5—Co1—N3 | 175.65 (14) | C6—N6—H6D | 112 (3) |
N4—Co1—N3 | 85.42 (14) | Co1—N6—H6D | 111 (3) |
N1—Co1—N6 | 91.91 (13) | H6C—N6—H6D | 107 (4) |
N5—Co1—N6 | 85.02 (13) | N1—C1—C2 | 106.8 (3) |
N4—Co1—N6 | 91.39 (13) | N1—C1—H1A | 110.4 |
N3—Co1—N6 | 91.83 (13) | C2—C1—H1A | 110.4 |
N1—Co1—N2 | 85.20 (13) | N1—C1—H1B | 110.4 |
N5—Co1—N2 | 91.96 (14) | C2—C1—H1B | 110.4 |
N4—Co1—N2 | 91.68 (13) | H1A—C1—H1B | 108.6 |
N3—Co1—N2 | 91.34 (15) | N2—C2—C1 | 107.5 (3) |
N6—Co1—N2 | 175.76 (13) | N2—C2—H2A | 110.2 |
C1—N1—Co1 | 109.8 (2) | C1—C2—H2A | 110.2 |
C1—N1—H1C | 114 (3) | N2—C2—H2B | 110.2 |
Co1—N1—H1C | 107 (3) | C1—C2—H2B | 110.2 |
C1—N1—H1D | 104 (3) | H2A—C2—H2B | 108.5 |
Co1—N1—H1D | 113 (3) | N3—C3—C4 | 107.2 (3) |
H1C—N1—H1D | 110 (4) | N3—C3—H3A | 110.3 |
C2—N2—Co1 | 109.5 (2) | C4—C3—H3A | 110.3 |
C2—N2—H2C | 107 (3) | N3—C3—H3B | 110.3 |
Co1—N2—H2C | 114 (3) | C4—C3—H3B | 110.3 |
C2—N2—H2D | 108 (4) | H3A—C3—H3B | 108.5 |
Co1—N2—H2D | 108 (3) | N4—C4—C3 | 107.3 (3) |
H2C—N2—H2D | 109 (5) | N4—C4—H4A | 110.3 |
C3—N3—Co1 | 109.7 (2) | C3—C4—H4A | 110.3 |
C3—N3—H3C | 101 (3) | N4—C4—H4B | 110.3 |
Co1—N3—H3C | 113 (3) | C3—C4—H4B | 110.3 |
C3—N3—H3D | 106 (4) | H4A—C4—H4B | 108.5 |
Co1—N3—H3D | 115 (4) | N5—C5—C6 | 107.0 (3) |
H3C—N3—H3D | 111 (5) | N5—C5—H5A | 110.3 |
C4—N4—Co1 | 109.7 (2) | C6—C5—H5A | 110.3 |
C4—N4—H4C | 110 (3) | N5—C5—H5B | 110.3 |
Co1—N4—H4C | 106 (3) | C6—C5—H5B | 110.3 |
C4—N4—H4D | 114 (3) | H5A—C5—H5B | 108.6 |
Co1—N4—H4D | 114 (3) | N6—C6—C5 | 106.7 (3) |
H4C—N4—H4D | 102 (4) | N6—C6—H6A | 110.4 |
C5—N5—Co1 | 110.6 (2) | C5—C6—H6A | 110.4 |
C5—N5—H5C | 106 (3) | N6—C6—H6B | 110.4 |
Co1—N5—H5C | 107 (3) | C5—C6—H6B | 110.4 |
C5—N5—H5D | 105 (3) | H6A—C6—H6B | 108.6 |
Co1—N1—C1—C2 | −39.6 (3) | N3—C3—C4—N4 | −49.3 (4) |
Co1—N2—C2—C1 | −37.5 (4) | Co1—N5—C5—C6 | 36.0 (3) |
N1—C1—C2—N2 | 49.9 (4) | Co1—N6—C6—C5 | 40.5 (3) |
Co1—N3—C3—C4 | 37.5 (3) | N5—C5—C6—N6 | −49.1 (4) |
Co1—N4—C4—C3 | 38.7 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1C···I2 | 0.87 (5) | 2.83 (5) | 3.598 (3) | 149 (4) |
N1—H1D···I2i | 0.87 (5) | 2.79 (5) | 3.616 (3) | 158 (4) |
N2—H2C···I3ii | 0.89 (5) | 3.04 (5) | 3.823 (3) | 149 (4) |
N2—H2D···I1iii | 0.80 (5) | 3.02 (5) | 3.756 (4) | 154 (4) |
N3—H3C···I2iv | 0.97 (5) | 3.25 (5) | 4.111 (3) | 149 (4) |
N3—H3C···I5iv | 0.97 (5) | 3.08 (5) | 3.586 (3) | 114 (3) |
N3—H3D···I1iii | 0.76 (5) | 3.18 (5) | 3.805 (4) | 142 (5) |
N4—H4C···I1 | 0.92 (5) | 2.77 (5) | 3.630 (3) | 155 (4) |
N4—H4D···I1v | 0.90 (5) | 2.90 (5) | 3.715 (3) | 152 (4) |
N5—H5C···I1v | 0.89 (5) | 2.95 (5) | 3.765 (3) | 154 (4) |
N5—H5C···I3ii | 0.89 (5) | 3.25 (5) | 3.639 (3) | 109 (3) |
N5—H5D···I4ii | 0.89 (5) | 3.05 (5) | 3.611 (3) | 123 (4) |
N6—H6C···I5 | 0.91 (5) | 2.89 (5) | 3.674 (3) | 145 (4) |
N6—H6D···I2iv | 0.95 (5) | 2.80 (5) | 3.684 (3) | 157 (4) |
Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) −x, y+1/2, −z+1/2; (iii) x+1/2, −y+1/2, −z+1; (iv) −x+1, y−1/2, −z+1/2; (v) x−1/2, −y+1/2, −z+1. |
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