metal-organic compounds
Potassium cis-[(R)-aspartato(2–)][(S)-aspartato(2–)]cobaltate(III) 3.5-hydrate at 120 K
aDepartamento de Química, Pontificia Universidade Católica do Rio de Janeiro, Rua Marquês de São Vicente 225, Gávea, 22453-999 Rio de Janeiro, RJ, Brazil, bDepartamento de Química Inorgânica, Instituto de Química, Universidade Federal do Rio de Janeiro, CP 68563, 21945-970 Rio de Janeiro, RJ, Brazil, and cDepartment of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland
*Correspondence e-mail: r.a.howie@abdn.ac.uk
The title compound, K[Co(C4H4NO4)2]3.5H2O, is a by-product resulting from adventitious oxidation, in the presence of racemic aspartic acid, of cobalt(II) in a cobaltous starting material. The presence of both enantiomeric forms of the tridentate aspartate ligand in the cobaltate anion is significant in eliminating the possibility of the existence of isomeric forms of the cis(N) isomer.
Comment
As part of our continuing study of transition metal complexes with amino acids (Felcman & de Miranda, 1997; de Miranda & Felcman, 2001; de Miranda et al., 2002; Felcman et al., 2003), we have isolated and characterized the title compound, (I), from an aqueous reaction mixture containing DL-aspartic acid (asp), guanidinoacetic acid (gaa) and CoII (1:1:1). Crystals of (I) were obtained after several months. No crystalline complex containing gaa, either alone or in a mixed complex with asp, appeared in a similar time.
The is shown in Fig. 1, and selected bond lengths and angles are given in Table 1. In the anion, an enantiomeric pair of asp dianions, with identical numbering of the atoms and distinguished by the suffixes A and B, act as tridentate ligands, creating octahedral coordination of atom Co1. The enantiomeric relationship of the asp dianions in the complex anion is evident in the torsion angles given in Table 1 and significant in later discussion of the of such complexes.
in the structure of (I)The K+ cation caps one face of the coordination octahedron of the anion to give a Co1⋯K1 distance of 3.6502 (14) Å. Its sevenfold coordination (Fig. 2) is completed by two non-coordinating O atoms associated with two further cobaltate anions and by two water molecules. A complex arrangement of K—O bonds connects the ions in layers parallel to (100), as shown schematically in Fig. 3. The connectivity creates, as the sub-unit, rings of four anions with four bridging K+ ions, two of which are seen in the case of the eight octahedra nearest the horizontal mid-line of Fig. 3. When the layer is seen edge-on, as in Fig. 4, it is clear that the distribution of the anions creates grooves running in the direction of c in which the K+ cations lie.
Also shown in Fig. 4 are the water molecules which, for the choice of origin used in the of the structure, occur in layers centred on x = and alternate with layers of anions centred on x = 0, the whole arrangement being replicated by cell translation in the direction of a. As shown in Table 2, a large number of N—H⋯O and O—H⋯O hydrogen bonds are present in the structure of (I). Only those hydrogen bonds involving the O5 water molecule, which is the only water molecule not contributing to the immediate coordination of the K+ ion, provide connectivity between adjacent layers of ions. The O5—H5A⋯O4B hydrogen bond is directed to one of the neighbouring layers and the other three, of the form N1B—H11B⋯O5iv, O6—H6A⋯O5v and O5—H5B⋯O2Bv [symmetry codes: (iv) −x + 1, −y + 1, −z; (v) −x + 1, y + , −z + ], to the other. Also given in Table 2 are details of two weak C—H⋯O hydrogen bonds.
The asp ligands can be considered to have three distinct atom types available for bonding to the central metal atom because, on the basis of the labelling scheme used in this report, atom O1 is part of the carboxylate group directly attached to the β to the When the octahedral complex is formed with one asp in each of its two enantiomeric forms, as is the case in (I), only one cis(N) isomer is possible in which cis(O1) and cis(O3) also occur. If, however, both asp ligands in the complex have the same enantiomeric form, say L, as in the cobaltate(III) compounds described by Oonish et al. (1973, 1975), the cis(N) arrangement is found in two isomeric forms, one with trans(O1) and the other with trans(O3), as is clearly demonstrated by Oonish et al. (1973).
(C2) of the ligand and is distinguishable, therefore, from atom O3, which is part of a carboxylate group which isThe presence of CoIII in (I), determined by the application of charge-balance considerations to the structural model, is at variance with the nature of the CoII salt starting material. However, the bond lengths and angles within the cobaltate anion in (I) are in good agreement with those found in other structures containing this type of anion such as, for example, those described by Oonish et al. (1973, 1975) and several other related structures. In contrast, recourse to the Cambridge Structural Database (Version 5.26; Allen, 2002) by means of the Chemical Database Service of the EPSRC (Fletcher et al., 1996) has revealed only one example of a cobaltous aspartate species, namely cobaltous aspartate trihydrate, (II) (Doyne et al., 1957), which is polymeric, has a Co:asp ratio of 1:1 [as distinct from 1:2 in (I)] and displays different (slightly longer) Co—N and C—O bond distances from those observed in the cobaltate anion in (I). It seems reasonable to suggest that, had not oxidation of the CoII of the starting material to CoIII taken place resulting in the formation of (I), then (II) might well have been the product of the reaction.
Experimental
To a hot solution (333 K) of guanidinoacetic acid (0.3513 g, 3 mmol) and DL-aspartic acid (0.3993 g, 3 mmol) in deionized water (100 ml) was slowly added a solution of cobalt(II) nitrate hexahydrate (0.8732 g, 3 mmol) in deionized water (5 ml). The reaction mixture was stirred at 333 K for 8 h, slowly cooled to 277 K, and the pH adjusted to 6.0 with KOH (3 M). The initial white precipitate which formed was filtered off and the filtrate was stored in a covered, but not sealed, vessel. Dark-blue crystals began to form after the fifth month and were collected after six months, washed with absolute ethanol and dried at 323 K. Although spectroscopy indicated the presence of at least some CoII in the bulk product, it is clear that the sample crystal, containing CoIII, is a by-product of this reaction, arising from CoIII either present as an impurity or created by oxidation of the initial CoII by oxygen in the air.
Crystal data
|
Refinement
|
|
As indicated by PLATON (Spek, 2003), the structural model used here sustains two symmetry-related [at (, 0, 0) and (, , )] solvent-accessible regions, each of volume 19 Å3, per Excluded from each of these regions of the structural model were two low electron density (approximately 2 e Å−3) features. This was accompanied by the supression, by means of the SQUEEZE option of PLATON, of their contribution to the intensity data. These features, less than 3 Å from the K+ ion, less than 1 Å apart and with site occupancy factors estimated to be of the order of 0.25, are perceived as representing additional highly disordered water molecules solvating the K+ ion and present in total to the extent of 0.5H2O per formula unit. The additional half-molecule of water has been included in the molecular formula but is, of course, absent from the structural model. In the final stages of H atoms attached to C and N atoms were placed in calculated positions, with C—H distances for tertiary and secondary C atoms of 1.00 and 0.99 Å, respectively, and for N, treated as secondary C, with N—H distance 0.92 Å. These H atoms were then refined with a riding model, with Uiso(H) = 1.2Ueq(C,N). Approximate positions for the H atoms of the water molecules were obtained from difference maps, the geometry of the water molecules idealized to give O—H distances of 0.84 Å and H—O—H angles in the range 101–105°, and the H atoms then refined with a riding model, with Uiso(H) = 1.5Ueq(O). In the final difference map, the largest peak is 1.01 Å from atom C2B.
Data collection: COLLECT (Hooft, 1998); cell DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and ATOMS for Windows (Dowty, 1998); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).
Supporting information
10.1107/S160053680503998X/lh6554sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S160053680503998X/lh6554Isup2.hkl
To a hot solution (333 K) of guanidinoacetic acid (0.3513 g, 3 mmol) and DL-aspartic acid (0.3993 g, 3 mmol) in deionized water (Volume?) was slowly added a solution of cobalt(II) nitrate hexahydrate (0.8732 g, 3 mmol) in deionized water (5 ml). The reaction mixture was stirred at 333 K for 8 h, slowly cooled to 277 K, and the pH adjusted to 6.0 with KOH (3 M). The initial white precipitate which formed was filtered off and the filtrate was stored in a covered, but not sealed, vessel. Dark-blue crystals began to form after the fifth month and were collected after six months, washed with absolute alcohol [ethanol?] and dried at 323 K. Although
spectroscopy indicated the presence of at least some CoII in the bulk product, it is clear that the sample crystal, containing CoIII, is a by-product of this reaction, arising from CoIII either present as an impurity or created by oxidation of the initial CoII by oxygen of the air.As indicated by PLATON (Spek, 2003), the structural model used here sustains two symmetry-related [at (1/2,0,0) and (1/2,1/2,1/2)] solvent-accessible regions, each of volume 19 Å3, per
Excluded from each of these regions of the structural model were two low electron density (approximately 2 e Å−3) features. This was accompanied by the supression, by means of the SQUEEZE option of PLATON, of their contribution to the intensity data. These features, less than 3 Å from the K atom, less than 1 Å apart and with site occupancy factors estimated to be of the order of 1/4, are perceived as representing additional highly disordered water molecules solvating the K atom and present in total to the extent of 0.5 H2O per formula unit. The additional half-molecule of water has been included in the but is, of course, absent from the structural model. In the final stages of H atoms attached to C and N atoms were placed in calculated positions, with C—H distances for tertiary and secondary C atoms of 1.00 and 0.99 Å, respectively, and for N, treated as secondary C, with N—H distance 0.92 Å. These H atoms were then refined with a riding model, with Uiso(H) = 1.2Ueq(C,N). Approximate positions for the H atoms of the water molecules were obtained from difference maps, the geometry of the water molecules idealized to give O—H distances of 0.84 Å and H—O—H angles in the range 100.9–104.8°, and the H atoms then refined with a riding model, with Uiso(H) = 1.5Ueq(O). In the final difference map, the largest peak is 1.01 Å from atom C2B.Data collection: COLLECT (Nonius, 1998); cell
DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and ATOMS for Windows (Dowty, 1998); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).Fig. 1. The asymmetric unit in (I). Displacement ellipsoids are drawn at the 20% probability level and H atoms are shown as small spheres of arbitrary radii. Dashed lines indicate hydrogen bonds. | |
Fig. 2. The coordination of the K atom in (I). Displacement ellipsoids are drawn at the 10% probability level and H atoms are shown as small spheres of arbitrary radii. [Symmetry codes: (i) x, −y + 1/2, z + 1/2; (ii) −x + 2, −y + 1, −z + 1.] | |
Fig. 3. A schematic view of a layer of ions in (I). The cobaltate anions are represented by coordination octahedra. Circles of arbitrary radii represent other atoms, large and black for K and lighter and decreasing in size for O and C in that order. H atoms and water molecules have been omitted for clarity. | |
Fig. 4. A schematic representation of the unit cell of (I), viewed along [001]. The cobaltate anions are represented by coordination octahedra. Circles of arbitrary radii represent other atoms, large and black for K and lighter and decreasing in size for O, C and H in that order. Dashed lines represent hydrogen bonds. |
K[Co(C4H5NO4)2]·3.5H2O | F(000) = 868 |
Mr = 423.27 | Dx = 1.866 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 3129 reflections |
a = 12.4853 (13) Å | θ = 2.9–27.5° |
b = 12.4689 (13) Å | µ = 1.48 mm−1 |
c = 9.6914 (8) Å | T = 120 K |
β = 92.952 (7)° | Block, dark blue |
V = 1506.7 (3) Å3 | 0.40 × 0.30 × 0.08 mm |
Z = 4 |
Nonius KappaCCD area-detector diffractometer | 3330 independent reflections |
Radiation source: Bruker Nonius FR591 rotating anode | 2568 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.045 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 3.2° |
ϕ and ω scans | h = −16→15 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | k = −16→16 |
Tmin = 0.517, Tmax = 0.891 | l = −12→12 |
16788 measured reflections |
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)] = 0.065 | Hydrogen site location: geom and difmap |
wR(F2) = 0.175 | H-atom parameters constrained |
S = 1.09 | w = 1/[σ2(Fo2) + (0.0839P)2 + 4.5102P] where P = (Fo2 + 2Fc2)/3 |
3330 reflections | (Δ/σ)max < 0.001 |
208 parameters | Δρmax = 1.24 e Å−3 |
0 restraints | Δρmin = −0.64 e Å−3 |
K[Co(C4H5NO4)2]·3.5H2O | V = 1506.7 (3) Å3 |
Mr = 423.27 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 12.4853 (13) Å | µ = 1.48 mm−1 |
b = 12.4689 (13) Å | T = 120 K |
c = 9.6914 (8) Å | 0.40 × 0.30 × 0.08 mm |
β = 92.952 (7)° |
Nonius KappaCCD area-detector diffractometer | 3330 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 2568 reflections with I > 2σ(I) |
Tmin = 0.517, Tmax = 0.891 | Rint = 0.045 |
16788 measured reflections |
R[F2 > 2σ(F2)] = 0.065 | 0 restraints |
wR(F2) = 0.175 | H-atom parameters constrained |
S = 1.09 | Δρmax = 1.24 e Å−3 |
3330 reflections | Δρmin = −0.64 e Å−3 |
208 parameters |
Experimental. Unit cell determined with DIRAX (Duisenberg, 1992; Duisenberg et al. 2000) but refined with the DENZO/COLLECT HKL package. Refs as: Duisenberg, A. J. M. (1992). J. Appl. Cryst. 25, 92–96. Duisenberg, A. J. M., Hooft, R. W. W., Schreurs, A. M. M. & Kroon, J. (2000). J. Appl. Cryst. 33, 893–898. |
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. |
x | y | z | Uiso*/Ueq | ||
Co1 | 0.83110 (5) | 0.35774 (5) | 0.19420 (6) | 0.0229 (2) | |
K1 | 0.75090 (11) | 0.57375 (9) | 0.42121 (13) | 0.0439 (3) | |
O1A | 0.8801 (3) | 0.3649 (2) | 0.3852 (3) | 0.0261 (7) | |
O2A | 1.0300 (3) | 0.3831 (3) | 0.5172 (3) | 0.0317 (8) | |
C1A | 0.9823 (4) | 0.3742 (3) | 0.4046 (5) | 0.0267 (10) | |
C2A | 1.0420 (4) | 0.3720 (4) | 0.2685 (5) | 0.0295 (10) | |
H21A | 1.1123 | 0.3343 | 0.2841 | 0.035* | |
N1A | 0.9735 (3) | 0.3124 (3) | 0.1647 (4) | 0.0264 (8) | |
H11A | 0.9804 | 0.2396 | 0.1777 | 0.032* | |
H12A | 0.9920 | 0.3289 | 0.0765 | 0.032* | |
C3A | 1.0608 (4) | 0.4847 (4) | 0.2154 (5) | 0.0326 (11) | |
H31A | 1.0981 | 0.5265 | 0.2902 | 0.039* | |
H32A | 1.1096 | 0.4801 | 0.1382 | 0.039* | |
C4A | 0.9615 (4) | 0.5457 (4) | 0.1658 (5) | 0.0274 (10) | |
O3A | 0.8679 (3) | 0.5034 (2) | 0.1644 (3) | 0.0264 (7) | |
O4A | 0.9747 (3) | 0.6394 (2) | 0.1257 (3) | 0.0330 (8) | |
O1B | 0.7903 (3) | 0.2133 (2) | 0.2163 (3) | 0.0270 (7) | |
O2B | 0.6924 (4) | 0.0825 (3) | 0.1201 (4) | 0.0545 (12) | |
C1B | 0.7245 (4) | 0.1754 (4) | 0.1234 (5) | 0.0354 (12) | |
C2B | 0.6882 (5) | 0.2621 (5) | 0.0140 (6) | 0.0491 (15) | |
H21B | 0.6743 | 0.2280 | −0.0785 | 0.059* | |
N1B | 0.7764 (3) | 0.3441 (3) | 0.0074 (4) | 0.0304 (9) | |
H11B | 0.7499 | 0.4085 | −0.0257 | 0.036* | |
H12B | 0.8290 | 0.3208 | −0.0486 | 0.036* | |
C3B | 0.5928 (6) | 0.3219 (5) | 0.0535 (6) | 0.0525 (16) | |
H31B | 0.5632 | 0.3603 | −0.0293 | 0.063* | |
H32B | 0.5381 | 0.2692 | 0.0797 | 0.063* | |
C4B | 0.6066 (5) | 0.3995 (5) | 0.1653 (6) | 0.0420 (13) | |
O3B | 0.6932 (3) | 0.4104 (3) | 0.2403 (3) | 0.0284 (7) | |
O4B | 0.5292 (4) | 0.4599 (5) | 0.1905 (6) | 0.0818 (17) | |
O5 | 0.3163 (3) | 0.4669 (3) | 0.1357 (5) | 0.0475 (10) | |
H5A | 0.3821 | 0.4518 | 0.1469 | 0.071* | |
H5B | 0.3056 | 0.4986 | 0.2107 | 0.071* | |
O6 | 0.7698 (4) | 0.7853 (3) | 0.5047 (6) | 0.0744 (17) | |
H6A | 0.7598 | 0.8298 | 0.4404 | 0.112* | |
H6B | 0.8282 | 0.8038 | 0.5449 | 0.112* | |
O7 | 0.6130 (6) | 0.6865 (6) | 0.2363 (8) | 0.117 (3) | |
H7A | 0.6556 | 0.6947 | 0.1728 | 0.175* | |
H7B | 0.5893 | 0.6240 | 0.2237 | 0.175* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Co1 | 0.0306 (4) | 0.0164 (3) | 0.0212 (3) | 0.0002 (2) | −0.0019 (2) | −0.0009 (2) |
K1 | 0.0616 (9) | 0.0277 (6) | 0.0415 (7) | −0.0043 (5) | −0.0062 (6) | −0.0053 (5) |
O1A | 0.035 (2) | 0.0226 (16) | 0.0199 (16) | 0.0018 (13) | −0.0024 (13) | −0.0001 (12) |
O2A | 0.042 (2) | 0.0193 (16) | 0.0327 (19) | −0.0008 (14) | −0.0092 (15) | 0.0028 (13) |
C1A | 0.032 (3) | 0.015 (2) | 0.032 (3) | −0.0003 (17) | −0.002 (2) | 0.0051 (17) |
C2A | 0.031 (3) | 0.024 (2) | 0.033 (3) | 0.0026 (19) | −0.002 (2) | 0.0043 (19) |
N1A | 0.032 (2) | 0.0168 (18) | 0.030 (2) | 0.0001 (15) | −0.0011 (16) | −0.0032 (15) |
C3A | 0.039 (3) | 0.027 (3) | 0.032 (3) | −0.004 (2) | 0.004 (2) | 0.0046 (19) |
C4A | 0.038 (3) | 0.024 (2) | 0.020 (2) | 0.0022 (19) | −0.0010 (19) | 0.0003 (17) |
O3A | 0.0326 (18) | 0.0143 (15) | 0.0314 (17) | 0.0007 (13) | −0.0054 (13) | 0.0015 (12) |
O4A | 0.050 (2) | 0.0215 (17) | 0.0269 (17) | −0.0100 (14) | −0.0040 (15) | 0.0047 (13) |
O1B | 0.0363 (19) | 0.0179 (15) | 0.0264 (17) | −0.0028 (13) | −0.0012 (14) | 0.0012 (12) |
O2B | 0.067 (3) | 0.049 (3) | 0.048 (2) | −0.031 (2) | 0.010 (2) | −0.0141 (19) |
C1B | 0.036 (3) | 0.043 (3) | 0.027 (3) | −0.001 (2) | 0.003 (2) | −0.006 (2) |
C2B | 0.053 (4) | 0.060 (4) | 0.034 (3) | 0.004 (3) | −0.003 (3) | −0.007 (3) |
N1B | 0.034 (2) | 0.034 (2) | 0.023 (2) | −0.0099 (17) | 0.0005 (17) | 0.0001 (16) |
C3B | 0.065 (4) | 0.044 (3) | 0.046 (4) | −0.001 (3) | −0.024 (3) | 0.001 (3) |
C4B | 0.032 (3) | 0.055 (3) | 0.039 (3) | 0.000 (3) | −0.004 (2) | 0.004 (3) |
O3B | 0.0293 (18) | 0.0288 (18) | 0.0268 (17) | 0.0038 (14) | −0.0012 (14) | −0.0045 (13) |
O4B | 0.040 (3) | 0.123 (5) | 0.081 (4) | 0.019 (3) | −0.007 (2) | −0.016 (3) |
O5 | 0.035 (2) | 0.055 (3) | 0.051 (2) | 0.0017 (18) | −0.0079 (18) | 0.0020 (19) |
O6 | 0.066 (3) | 0.035 (2) | 0.116 (4) | 0.007 (2) | −0.046 (3) | −0.018 (3) |
O7 | 0.117 (6) | 0.103 (5) | 0.124 (6) | 0.045 (4) | −0.050 (5) | −0.035 (4) |
Co1—O1B | 1.886 (3) | C3A—H32A | 0.9900 |
Co1—O3A | 1.899 (3) | C4A—O4A | 1.245 (6) |
Co1—N1A | 1.902 (4) | C4A—O3A | 1.282 (6) |
Co1—N1B | 1.909 (4) | O1B—C1B | 1.278 (6) |
Co1—O3B | 1.917 (3) | O2B—C1B | 1.226 (7) |
Co1—O1A | 1.921 (3) | O2B—K1iii | 2.862 (4) |
K1—O3B | 2.759 (3) | C1B—C2B | 1.565 (8) |
K1—O6 | 2.766 (4) | C2B—C3B | 1.472 (9) |
K1—O7 | 2.799 (6) | C2B—N1B | 1.506 (8) |
K1—O2Ai | 2.821 (4) | C2B—H21B | 1.0000 |
K1—O2Bii | 2.862 (4) | N1B—H11B | 0.9200 |
K1—O3A | 3.078 (4) | N1B—H12B | 0.9200 |
K1—O1A | 3.092 (3) | C3B—C4B | 1.456 (8) |
O1A—C1A | 1.286 (6) | C3B—H31B | 0.9900 |
O2A—C1A | 1.221 (6) | C3B—H32B | 0.9900 |
O2A—K1i | 2.821 (4) | C4B—O4B | 1.258 (8) |
C1A—C2A | 1.549 (7) | C4B—O3B | 1.279 (6) |
C2A—N1A | 1.486 (6) | O5—H5A | 0.8434 |
C2A—C3A | 1.518 (6) | O5—H5B | 0.8445 |
C2A—H21A | 1.0000 | O6—H6A | 0.8397 |
N1A—H11A | 0.9200 | O6—H6B | 0.8406 |
N1A—H12A | 0.9200 | O7—H7A | 0.8400 |
C3A—C4A | 1.512 (7) | O7—H7B | 0.8400 |
C3A—H31A | 0.9900 | Co1—K1 | 3.6502 (14) |
O1B—Co1—O3A | 177.34 (14) | C2A—N1A—H12A | 110.7 |
O1B—Co1—N1A | 89.62 (16) | Co1—N1A—H12A | 110.7 |
O3A—Co1—N1A | 91.48 (16) | H11A—N1A—H12A | 108.8 |
O1B—Co1—N1B | 86.38 (15) | C4A—C3A—C2A | 115.8 (4) |
O3A—Co1—N1B | 91.08 (15) | C4A—C3A—H31A | 108.3 |
N1A—Co1—N1B | 97.02 (18) | C2A—C3A—H31A | 108.3 |
O1B—Co1—O3B | 92.85 (15) | C4A—C3A—H32A | 108.3 |
O3A—Co1—O3B | 86.27 (14) | C2A—C3A—H32A | 108.3 |
N1A—Co1—O3B | 174.29 (15) | H31A—C3A—H32A | 107.4 |
N1B—Co1—O3B | 88.27 (16) | O4A—C4A—O3A | 121.2 (4) |
O1B—Co1—O1A | 90.54 (13) | O4A—C4A—C3A | 116.9 (4) |
O3A—Co1—O1A | 91.97 (13) | O3A—C4A—C3A | 121.9 (4) |
N1A—Co1—O1A | 84.57 (15) | C4A—O3A—Co1 | 128.3 (3) |
N1B—Co1—O1A | 176.52 (15) | C4A—O3A—K1 | 110.2 (3) |
O3B—Co1—O1A | 90.26 (14) | Co1—O3A—K1 | 91.21 (12) |
O3B—K1—O6 | 154.90 (14) | C1B—O1B—Co1 | 116.2 (3) |
O3B—K1—O7 | 80.32 (15) | C1B—O2B—K1iii | 124.5 (3) |
O6—K1—O7 | 75.45 (17) | O2B—C1B—O1B | 124.4 (5) |
O3B—K1—O2Ai | 119.60 (11) | O2B—C1B—C2B | 123.5 (5) |
O6—K1—O2Ai | 71.88 (12) | O1B—C1B—C2B | 112.0 (5) |
O7—K1—O2Ai | 126.7 (2) | C3B—C2B—N1B | 105.7 (5) |
O3B—K1—O2Bii | 81.86 (12) | C3B—C2B—C1B | 112.6 (5) |
O6—K1—O2Bii | 118.22 (16) | N1B—C2B—C1B | 108.1 (4) |
O7—K1—O2Bii | 127.1 (2) | C3B—C2B—H21B | 110.1 |
O2Ai—K1—O2Bii | 105.39 (12) | N1B—C2B—H21B | 110.1 |
O3B—K1—O3A | 52.76 (9) | C1B—C2B—H21B | 110.1 |
O6—K1—O3A | 118.15 (15) | C2B—N1B—Co1 | 104.3 (3) |
O7—K1—O3A | 85.84 (18) | C2B—N1B—H11B | 110.9 |
O2Ai—K1—O3A | 74.34 (10) | Co1—N1B—H11B | 110.9 |
O2Bii—K1—O3A | 119.93 (11) | C2B—N1B—H12B | 110.9 |
O3B—K1—O1A | 55.06 (9) | Co1—N1B—H12B | 110.9 |
O6—K1—O1A | 143.04 (13) | H11B—N1B—H12B | 108.9 |
O7—K1—O1A | 131.14 (15) | C4B—C3B—C2B | 117.6 (5) |
O2Ai—K1—O1A | 71.27 (9) | C4B—C3B—H31B | 107.9 |
O2Bii—K1—O1A | 69.84 (10) | C2B—C3B—H31B | 107.9 |
O3A—K1—O1A | 52.89 (8) | C4B—C3B—H32B | 107.9 |
C1A—O1A—Co1 | 114.1 (3) | C2B—C3B—H32B | 107.9 |
C1A—O1A—K1 | 115.3 (3) | H31B—C3B—H32B | 107.2 |
Co1—O1A—K1 | 90.35 (11) | O4B—C4B—O3B | 117.5 (5) |
C1A—O2A—K1i | 129.0 (3) | O4B—C4B—C3B | 118.6 (5) |
O2A—C1A—O1A | 125.0 (5) | O3B—C4B—C3B | 123.9 (5) |
O2A—C1A—C2A | 121.9 (4) | C4B—O3B—Co1 | 125.1 (3) |
O1A—C1A—C2A | 113.1 (4) | C4B—O3B—K1 | 128.7 (3) |
N1A—C2A—C3A | 109.1 (4) | Co1—O3B—K1 | 101.11 (13) |
N1A—C2A—C1A | 107.4 (4) | H5A—O5—H5B | 100.9 |
C3A—C2A—C1A | 111.2 (4) | K1—O6—H6A | 114.0 |
N1A—C2A—H21A | 109.7 | K1—O6—H6B | 117.1 |
C3A—C2A—H21A | 109.7 | H6A—O6—H6B | 104.8 |
C1A—C2A—H21A | 109.7 | K1—O7—H7A | 98.0 |
C2A—N1A—Co1 | 105.1 (3) | K1—O7—H7B | 80.1 |
C2A—N1A—H11A | 110.7 | H7A—O7—H7B | 103.8 |
Co1—N1A—H11A | 110.7 | ||
O2A—C1A—C2A—N1A | 154.3 (4) | O2B—C1B—C2B—N1B | −153.2 (5) |
O1A—C1A—C2A—N1A | −25.2 (5) | O1B—C1B—C2B—N1B | 27.4 (6) |
O2A—C1A—C2A—C3A | −86.4 (5) | O2B—C1B—C2B—C3B | 90.5 (7) |
O1A—C1A—C2A—C3A | 94.1 (5) | O1B—C1B—C2B—C3B | −89.0 (6) |
N1A—C2A—C3A—C4A | 50.6 (6) | N1B—C2B—C3B—C4B | −45.0 (7) |
C1A—C2A—C3A—C4A | −67.7 (5) | C1B—C2B—C3B—C4B | 72.8 (7) |
C2A—C3A—C4A—O4A | 177.9 (4) | C2B—C3B—C4B—O4B | 172.2 (6) |
C2A—C3A—C4A—O3A | −2.3 (7) | C2B—C3B—C4B—O3B | −7.7 (9) |
Symmetry codes: (i) −x+2, −y+1, −z+1; (ii) x, −y+1/2, z+1/2; (iii) x, −y+1/2, z−1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H11A···O2Aiii | 0.92 | 2.29 | 2.930 (5) | 126 |
N1A—H11A···O4Aiv | 0.92 | 2.32 | 3.011 (5) | 131 |
N1A—H12A···O4Av | 0.92 | 2.06 | 2.981 (5) | 177 |
N1B—H11B···O5vi | 0.92 | 2.04 | 2.942 (6) | 168 |
N1B—H12B···O1Biii | 0.92 | 2.34 | 2.925 (5) | 121 |
N1B—H12B···O1Aiii | 0.92 | 2.49 | 3.166 (5) | 130 |
O5—H5A···O4B | 0.84 | 1.87 | 2.685 (6) | 163 |
O5—H5B···O2Bvii | 0.84 | 1.94 | 2.777 (6) | 169 |
O6—H6A···O5vii | 0.84 | 2.07 | 2.826 (6) | 149 |
O6—H6B···O4Aviii | 0.84 | 2.08 | 2.914 (6) | 174 |
O7—H7A···O6ix | 0.84 | 2.23 | 3.074 (11) | 17 |
O7—H7B···O4B | 0.84 | 2.20 | 3.038 (10) | 179 |
C2B—H21B···O3Biii | 1.00 | 2.48 | 3.419 (7) | 156 |
C3A—H32A···O5x | 0.99 | 2.59 | 3.328 (7) | 132 |
Symmetry codes: (iii) x, −y+1/2, z−1/2; (iv) −x+2, y−1/2, −z+1/2; (v) −x+2, −y+1, −z; (vi) −x+1, −y+1, −z; (vii) −x+1, y+1/2, −z+1/2; (viii) x, −y+3/2, z+1/2; (ix) x, −y+3/2, z−1/2; (x) x+1, y, z. |
Experimental details
Crystal data | |
Chemical formula | K[Co(C4H5NO4)2]·3.5H2O |
Mr | 423.27 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 120 |
a, b, c (Å) | 12.4853 (13), 12.4689 (13), 9.6914 (8) |
β (°) | 92.952 (7) |
V (Å3) | 1506.7 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.48 |
Crystal size (mm) | 0.40 × 0.30 × 0.08 |
Data collection | |
Diffractometer | Nonius KappaCCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) |
Tmin, Tmax | 0.517, 0.891 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 16788, 3330, 2568 |
Rint | 0.045 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.065, 0.175, 1.09 |
No. of reflections | 3330 |
No. of parameters | 208 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.24, −0.64 |
Computer programs: COLLECT (Nonius, 1998), DENZO (Otwinowski & Minor, 1997) and COLLECT, DENZO and COLLECT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997) and ATOMS for Windows (Dowty, 1998), SHELXL97 and PLATON (Spek, 2003).
Co1—O1B | 1.886 (3) | K1—O6 | 2.766 (4) |
Co1—O3A | 1.899 (3) | K1—O7 | 2.799 (6) |
Co1—N1A | 1.902 (4) | K1—O2Ai | 2.821 (4) |
Co1—N1B | 1.909 (4) | K1—O2Bii | 2.862 (4) |
Co1—O3B | 1.917 (3) | K1—O3A | 3.078 (4) |
Co1—O1A | 1.921 (3) | K1—O1A | 3.092 (3) |
K1—O3B | 2.759 (3) | ||
O1B—Co1—O3A | 177.34 (14) | N1A—Co1—O3B | 174.29 (15) |
O1B—Co1—N1A | 89.62 (16) | N1B—Co1—O3B | 88.27 (16) |
O3A—Co1—N1A | 91.48 (16) | O1B—Co1—O1A | 90.54 (13) |
O1B—Co1—N1B | 86.38 (15) | O3A—Co1—O1A | 91.97 (13) |
O3A—Co1—N1B | 91.08 (15) | N1A—Co1—O1A | 84.57 (15) |
N1A—Co1—N1B | 97.02 (18) | N1B—Co1—O1A | 176.52 (15) |
O1B—Co1—O3B | 92.85 (15) | O3B—Co1—O1A | 90.26 (14) |
O3A—Co1—O3B | 86.27 (14) | ||
N1A—C2A—C3A—C4A | 50.6 (6) | N1B—C2B—C3B—C4B | −45.0 (7) |
C1A—C2A—C3A—C4A | −67.7 (5) | C1B—C2B—C3B—C4B | 72.8 (7) |
Symmetry codes: (i) −x+2, −y+1, −z+1; (ii) x, −y+1/2, z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H11A···O2Aiii | 0.92 | 2.29 | 2.930 (5) | 126 |
N1A—H11A···O4Aiv | 0.92 | 2.32 | 3.011 (5) | 131 |
N1A—H12A···O4Av | 0.92 | 2.06 | 2.981 (5) | 177 |
N1B—H11B···O5vi | 0.92 | 2.04 | 2.942 (6) | 168 |
N1B—H12B···O1Biii | 0.92 | 2.34 | 2.925 (5) | 121 |
N1B—H12B···O1Aiii | 0.92 | 2.49 | 3.166 (5) | 130 |
O5—H5A···O4B | 0.84 | 1.87 | 2.685 (6) | 163 |
O5—H5B···O2Bvii | 0.84 | 1.94 | 2.777 (6) | 169 |
O6—H6A···O5vii | 0.84 | 2.07 | 2.826 (6) | 149 |
O6—H6B···O4Aviii | 0.84 | 2.08 | 2.914 (6) | 174 |
O7—H7A···O6ix | 0.84 | 2.23 | 3.074 (11) | 17 |
O7—H7B···O4B | 0.84 | 2.20 | 3.038 (10) | 179 |
C2B—H21B···O3Biii | 1.00 | 2.48 | 3.419 (7) | 156 |
C3A—H32A···O5x | 0.99 | 2.59 | 3.328 (7) | 132 |
Symmetry codes: (iii) x, −y+1/2, z−1/2; (iv) −x+2, y−1/2, −z+1/2; (v) −x+2, −y+1, −z; (vi) −x+1, −y+1, −z; (vii) −x+1, y+1/2, −z+1/2; (viii) x, −y+3/2, z+1/2; (ix) x, −y+3/2, z−1/2; (x) x+1, y, z. |
Acknowledgements
We acknowledge the use of the Chemical Database Service at Daresbury and the X-ray Crystallographic Service in Southampton, England, both services being provided by the EPSRC.
References
Allen, F. H. (2002). Acta Cryst. B58, 380–388. Web of Science CrossRef CAS IUCr Journals Google Scholar
Dowty, E. (1998). ATOMS for Windows. Version 4.1. Shape Software, 521 Hidden Valley Road, Kingsport, TN 37663, USA. Google Scholar
Doyne, T., Pepinsky, R. & Watanabe, T. (1957). Acta Cryst. 10, 438–439. CSD CrossRef IUCr Journals Web of Science Google Scholar
Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565. CrossRef IUCr Journals Google Scholar
Felcman, J. & de Miranda, J. L. (1997). J. Braz. Chem. Soc. 8, 575–580. CrossRef CAS Google Scholar
Felcman, J., Howie, R. A., de Miranda, J. L., Skakle, J. M. S. & Wardell, J. L. (2003). Acta Cryst. C59, m103–m106. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Fletcher, D. A., McMeeking, R. F. & Parkin, D. (1996). J. Chem. Inf. Comput. Sci. 36, 746–749. CrossRef CAS Web of Science Google Scholar
Hooft, R. W. W. (1998). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Miranda, J. L. de & Felcman, J. (2001). Synth. React. Inorg. Met. Chem. 31, 873–894. Web of Science CrossRef Google Scholar
Miranda, J. L. de, Felcman, J., Wardell, J. L. & Skakle, J. M. S. (2002). Acta Cryst. C58, m471–m474. Web of Science CSD CrossRef IUCr Journals Google Scholar
Oonish, I., Sato, S. & Saito, Y. (1975). Acta Cryst. B31, 1318–1324. CSD CrossRef IUCr Journals Web of Science Google Scholar
Oonish, I., Shibata, M., Marumo, F. & Saito, Y. (1973). Acta Cryst. B29, 2448–2455. CSD CrossRef IUCr Journals Web of Science Google Scholar
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press. Google Scholar
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2003). SADABS. Version 2.10. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13. Web of Science CrossRef CAS IUCr Journals Google Scholar
© International Union of Crystallography. Prior permission is not required to reproduce short quotations, tables and figures from this article, provided the original authors and source are cited. For more information, click here.
As part of our continuing study of transition metal complexes with amino acids (Felcman & de Miranda, 1997; de Miranda & Felcman, 2001; de Miranda et al., 2002; Felcman et al., 2003), we have isolated and characterized the title compound, (I), from an aqueous reaction mixture containing DL-aspartic acid (asp), guanidineacetic acid (gaa) and CoII (1:1:1). Crystals of (I) were obtained after several months. No crystalline complex containing gaa, either alone or in a mixed complex with asp, appeared in a similar time.
The asymmetric unit in the structure of (I) is shown in Fig. 1, and selected bond lengths and angles are given in Table 1. In the anion, an enantiomeric pair of asp dianions, with identical labelling of the atoms and distinguished by the suffixes A and B, act as tridentate ligands, creating octahedral coordination of atom Co1. The enantiomeric relationship of the asp dianions in the complex anion is evident in the torsion angles given in Table 1 and significant in later discussion of the isomerism of such complexes.
The K atom caps one face of the coordination octahedron of the anion to give a Co1···K1 distance of 3.6502 (14) Å. Its sevenfold coordination (Fig. 2) is completed by two non-coordinating O atoms associated with two further cobaltate anions and by two water molecules. A complex arrangement of K—O bonds connects the ions in layers parallel to (100), as shown schematically in Fig. 3. The connectivity creates, as the sub-unit, rings of four anions with four bridging K atoms, two of which are seen in the case of the eight octahedra nearest the horizontal mid-line of Fig. 3. When the layer is seen edge-on, as in Fig. 4, it is clear that the distribution of the anions creates grooves running in the direction of c in which the K cations lie.
Also shown in Fig. 4 are the water molecules which, for the choice of origin used in the refinement of the structure, occur in layers centred on x = 1/2 and alternate with layers of anions centred on x = 0, the whole arrangement being replicated by cell translation in the direction of a. As shown in Table 2, a large number of N—H···O and O—H···O hydrogen bonds are present in the structure of (I). Only those hydrogen bonds involving the O5 water molecule, which is the only water molecule not contributing to the immediate coordination of the K atom, provide connectivity between adjacent layers of ions. The O5—H5A···O4B hydrogen bond is directed to one of the neighbouring layers and the other three, of the form N1B—H11B···O5iv, O6—H6A···O5v and O5—H5B···O2Bv [symmetry codes: (iv) −x + 1, −y + 1, −z; (v) −x + 1, y + 1/2, −z + 1/2], to the other. Also given in Table 2 are details of two weak C—H···O hydrogen bonds.
The asp ligands can be considered to have three distinct atom types available for bonding to the central metal atom because, on the basis of the labelling scheme used in this report, atom O1 is part of the carboxyl group directly attached to the asymmetric centre (C2) of the ligand and is distinguishable, therefore, from atom O3, which is part of a carboxyl group which is β to the asymmetric centre. When the octahedral complex is formed with one asp in each of its two enantiomeric forms, as is the case in (I), only one cis(N) isomer is possible in which cis(O1) and cis(O3) also occur. If, however, both asp ligands in the complex have the same enantiomeric form, say L, as in the cobaltate(III) compounds described by Oonish et al. (1973, 1975), the cis(N) arrangement is found in two isomeric forms, one with trans(O1) and the other with trans(O3), as is clearly demonstrated by Oonish et al. (1973).
The presence of CoIII in (I), determined by the application of charge-balance considerations to the structural model, is at variance with the nature of the CoII salt starting material. However, the bond lengths and angles within the cobaltate anion in (I) are in good agreement with those found in other structures containing this type of anion such as, for example, those described by Oonish et al. (1973, 1975) and several other related structures. In contrast, recourse to the Cambridge Structural Database (Version?; Allen, 2002) by means the Chemical Database Service of the EPSRC (Fletcher et al., 1996) has revealed only one example of a cobaltous aspartate species, namely cobaltous aspartate trihydrate, (II) (Doyne et al., 1957), which is polymeric, has a Co:asp ratio of 1:1 [as distinct from 1:2 in (I)] and displays different (slightly longer) Co—N and C—O bond distances from those observed in the cobaltate anion in (I). It seems reasonable to suggest that, had not oxidation of the CoII of the starting material to CoIII taken place resulting in the formation of (I), then (II) might well have been the product of the reaction.