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Potassium cis-[(R)-aspartato(2–)][(S)-aspartato(2–)]cobaltate(III) 3.5-hydrate at 120 K

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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

(Received 16 November 2005; accepted 1 December 2005; online 10 December 2005)

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[Felcman, J. & de Miranda, J. L. (1997). J. Braz. Chem. Soc. 8, 575-580.]; de Miranda & Felcman, 2001[Miranda, J. L. de & Felcman, J. (2001). Synth. React. Inorg. Met. Chem. 31, 873-894.]; de Miranda et al., 2002[Miranda, J. L. de, Felcman, J., Wardell, J. L. & Skakle, J. M. S. (2002). Acta Cryst. C58, m471-m474.]; Felcman et al., 2003[Felcman, J., Howie, R. A., de Miranda, J. L., Skakle, J. M. S. & Wardell, J. L. (2003). Acta Cryst. C59, m103-m106.]), we have isolated and characterized the title compound, (I)[link], from an aqueous reaction mixture containing DL-aspartic acid (asp), guanidinoacetic acid (gaa) and CoII (1:1:1). Crystals of (I)[link] were obtained after several months. No crystalline complex containing gaa, either alone or in a mixed complex with asp, appeared in a similar time.

[Scheme 1]

The asymmetric unit in the structure of (I)[link] is shown in Fig. 1[link], and selected bond lengths and angles are given in Table 1[link]. 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[link] and significant in later discussion of the isomerism of such complexes.

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[link]) 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[link]. 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[link]. When the layer is seen edge-on, as in Fig. 4[link], 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[link] are the water mol­ecules which, for the choice of origin used in the refinement of the structure, occur in layers centred on x = [{1 \over 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[link], a large number of N—H⋯O and O—H⋯O hydrogen bonds are present in the structure of (I)[link]. 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 + [{1\over 2}], −z + [{1\over 2}]], to the other. Also given in Table 2[link] 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 asymmetric centre (C2) of the ligand and is distinguishable, therefore, from atom O3, which is part of a carboxylate 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)[link], 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[Oonish, I., Shibata, M., Marumo, F. & Saito, Y. (1973). Acta Cryst. B29, 2448-2455.], 1975[Oonish, I., Sato, S. & Saito, Y. (1975). Acta Cryst. B31, 1318-1324.]), 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[Oonish, I., Shibata, M., Marumo, F. & Saito, Y. (1973). Acta Cryst. B29, 2448-2455.]).

The presence of CoIII in (I)[link], 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)[link] 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[Oonish, I., Shibata, M., Marumo, F. & Saito, Y. (1973). Acta Cryst. B29, 2448-2455.], 1975[Oonish, I., Sato, S. & Saito, Y. (1975). Acta Cryst. B31, 1318-1324.]) and several other related structures. In contrast, recourse to the Cambridge Structural Database (Version 5.26; Allen, 2002[Allen, F. H. (2002). Acta Cryst. B58, 380-388.]) by means of the Chemical Database Service of the EPSRC (Fletcher et al., 1996[Fletcher, D. A., McMeeking, R. F. & Parkin, D. (1996). J. Chem. Inf. Comput. Sci. 36, 746-749.]) has revealed only one example of a cobaltous aspartate species, namely cobaltous aspartate trihydrate, (II) (Doyne et al., 1957[Doyne, T., Pepinsky, R. & Watanabe, T. (1957). Acta Cryst. 10, 438-439.]), which is polymeric, has a Co:asp ratio of 1:1 [as distinct from 1:2 in (I)[link]] and displays different (slightly longer) Co—N and C—O bond distances from those observed in the cobaltate anion in (I)[link]. 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)[link], then (II) might well have been the product of the reaction.

[Figure 1]
Figure 1
The asymmetric unit of (I)[link]. 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.
[Figure 2]
Figure 2
The coordination of the K+ cation in (I)[link]. 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\over 2}], z + [{1\over 2}]; (ii) −x + 2, −y + 1, −z + 1.]
[Figure 3]
Figure 3
A schematic view of a layer of ions in (I)[link]. 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.
[Figure 4]
Figure 4
A schematic representation of the unit cell contents of (I)[link], 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.

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 electron paramagnetic resonance 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
  • K[Co(C4H5NO4)2]·3.5H2O

  • Mr = 423.27

  • Monoclinic, P 21 /c

  • a = 12.4853 (13) Å

  • b = 12.4689 (13) Å

  • c = 9.6914 (8) Å

  • β = 92.952 (7)°

  • V = 1506.7 (3) Å3

  • Z = 4

  • Dx = 1.866 Mg m−3

  • Mo Kα radiation

  • Cell parameters from 3129 reflections

  • θ = 2.9–27.5°

  • μ = 1.48 mm−1

  • T = 120 (2) K

  • Block, dark blue

  • 0.40 × 0.30 × 0.08 mm

Data collection
  • Nonius KappaCCD area-detector diffractometer

  • φ and ω scans

  • Absorption correction: multi-scan(SADABS; Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. Version 2.10. Bruker AXS Inc., Madison, Wisconsin, USA.])Tmin = 0.517, Tmax = 0.891

  • 16788 measured reflections

  • 3330 independent reflections

  • 2568 reflections with I > 2σ(I)

  • Rint = 0.045

  • θmax = 27.5°

  • h = −16 → 15

  • k = −16 → 16

  • l = −12 → 12

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.065

  • wR(F2) = 0.175

  • S = 1.09

  • 3330 reflections

  • 208 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(Fo2) + (0.0839P)2 + 4.5102P] where P = (Fo2 + 2Fc2)/3

  • (Δ/σ)max < 0.001

  • Δρmax = 1.24 e Å−3

  • Δρmin = −0.64 e Å−3

Table 1
Selected geometric parameters (Å, °)[link]

Co1—O1B 1.886 (3)
Co1—O3A 1.899 (3)
Co1—N1A 1.902 (4)
Co1—N1B 1.909 (4)
Co1—O3B 1.917 (3)
Co1—O1A 1.921 (3)
K1—O3B 2.759 (3)
K1—O6 2.766 (4)
K1—O7 2.799 (6)
K1—O2Ai 2.821 (4)
K1—O2Bii 2.862 (4)
K1—O3A 3.078 (4)
K1—O1A 3.092 (3)
O1B—Co1—O3A 177.34 (14)
O1B—Co1—N1A 89.62 (16)
O3A—Co1—N1A 91.48 (16)
O1B—Co1—N1B 86.38 (15)
O3A—Co1—N1B 91.08 (15)
N1A—Co1—N1B 97.02 (18)
O1B—Co1—O3B 92.85 (15)
O3A—Co1—O3B 86.27 (14)
N1A—Co1—O3B 174.29 (15)
N1B—Co1—O3B 88.27 (16)
O1B—Co1—O1A 90.54 (13)
O3A—Co1—O1A 91.97 (13)
N1A—Co1—O1A 84.57 (15)
N1B—Co1—O1A 176.52 (15)
O3B—Co1—O1A 90.26 (14)
N1A—C2A—C3A—C4A 50.6 (6)
C1A—C2A—C3A—C4A −67.7 (5)
N1B—C2B—C3B—C4B −45.0 (7)
C1B—C2B—C3B—C4B 72.8 (7)
Symmetry codes: (i) -x+2, -y+1, -z+1; (ii) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}].

Table 2
Hydrogen-bond geometry (Å, °)[link]

D—H⋯A D—H H⋯A DA 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+{\script{1\over 2}}, z-{\script{1\over 2}}]; (iv) [-x+2, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]; (v) -x+2, -y+1, -z; (vi) -x+1, -y+1, -z; (vii) [-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]; (viii) [x, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]; (ix) [x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]; (x) x+1, y, z.

As indicated by PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]), the structural model used here sustains two symmetry-related [at ([{1 \over 2}], 0, 0) and ([{1 \over 2}], [{1 \over 2}], [{1 \over 2}])] solvent-accessible regions, each of volume 19 Å3, per unit cell. 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 refinement, 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[Hooft, R. W. W. (1998). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO (Otwinowski & Minor, 1997[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.]) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997[Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.]); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and ATOMS for Windows (Dowty, 1998[Dowty, E. (1998). ATOMS for Windows. Version 4.1. Shape Software, 521 Hidden Valley Road, Kingsport, TN 37663, USA.]); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003[Spek, A. L. (2003). J. Appl. Cryst. 36, 7-13.]).

Supporting information


Comment top

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.

Experimental top

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 electron paramagnetic resonance 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.

Refinement top

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 unit cell. 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 molecular formula but is, of course, absent from the structural model. In the final stages of refinement, 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.

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: 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).

Figures top
[Figure 1] 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.
[Figure 2] 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.]
[Figure 3] 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.
[Figure 4] 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.
Potassium cis-[(R)-aspartato(2-)][(S)-aspartato(2-)]cobaltate(III) 3.5-hydrate top
Crystal data top
K[Co(C4H5NO4)2]·3.5H2OF(000) = 868
Mr = 423.27Dx = 1.866 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 3129 reflections
a = 12.4853 (13) Åθ = 2.9–27.5°
b = 12.4689 (13) ŵ = 1.48 mm1
c = 9.6914 (8) ÅT = 120 K
β = 92.952 (7)°Block, dark blue
V = 1506.7 (3) Å30.40 × 0.30 × 0.08 mm
Z = 4
Data collection top
Nonius KappaCCD area-detector
diffractometer
3330 independent reflections
Radiation source: Bruker Nonius FR591 rotating anode2568 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.045
Detector resolution: 9.091 pixels mm-1θmax = 27.5°, θmin = 3.2°
ϕ and ω scansh = 1615
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
k = 1616
Tmin = 0.517, Tmax = 0.891l = 1212
16788 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.065Hydrogen site location: geom and difmap
wR(F2) = 0.175H-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 parametersΔρmax = 1.24 e Å3
0 restraintsΔρmin = 0.64 e Å3
Crystal data top
K[Co(C4H5NO4)2]·3.5H2OV = 1506.7 (3) Å3
Mr = 423.27Z = 4
Monoclinic, P21/cMo Kα radiation
a = 12.4853 (13) ŵ = 1.48 mm1
b = 12.4689 (13) ÅT = 120 K
c = 9.6914 (8) Å0.40 × 0.30 × 0.08 mm
β = 92.952 (7)°
Data collection top
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 = 0.891Rint = 0.045
16788 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0650 restraints
wR(F2) = 0.175H-atom parameters constrained
S = 1.09Δρmax = 1.24 e Å3
3330 reflectionsΔρmin = 0.64 e Å3
208 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Co10.83110 (5)0.35774 (5)0.19420 (6)0.0229 (2)
K10.75090 (11)0.57375 (9)0.42121 (13)0.0439 (3)
O1A0.8801 (3)0.3649 (2)0.3852 (3)0.0261 (7)
O2A1.0300 (3)0.3831 (3)0.5172 (3)0.0317 (8)
C1A0.9823 (4)0.3742 (3)0.4046 (5)0.0267 (10)
C2A1.0420 (4)0.3720 (4)0.2685 (5)0.0295 (10)
H21A1.11230.33430.28410.035*
N1A0.9735 (3)0.3124 (3)0.1647 (4)0.0264 (8)
H11A0.98040.23960.17770.032*
H12A0.99200.32890.07650.032*
C3A1.0608 (4)0.4847 (4)0.2154 (5)0.0326 (11)
H31A1.09810.52650.29020.039*
H32A1.10960.48010.13820.039*
C4A0.9615 (4)0.5457 (4)0.1658 (5)0.0274 (10)
O3A0.8679 (3)0.5034 (2)0.1644 (3)0.0264 (7)
O4A0.9747 (3)0.6394 (2)0.1257 (3)0.0330 (8)
O1B0.7903 (3)0.2133 (2)0.2163 (3)0.0270 (7)
O2B0.6924 (4)0.0825 (3)0.1201 (4)0.0545 (12)
C1B0.7245 (4)0.1754 (4)0.1234 (5)0.0354 (12)
C2B0.6882 (5)0.2621 (5)0.0140 (6)0.0491 (15)
H21B0.67430.22800.07850.059*
N1B0.7764 (3)0.3441 (3)0.0074 (4)0.0304 (9)
H11B0.74990.40850.02570.036*
H12B0.82900.32080.04860.036*
C3B0.5928 (6)0.3219 (5)0.0535 (6)0.0525 (16)
H31B0.56320.36030.02930.063*
H32B0.53810.26920.07970.063*
C4B0.6066 (5)0.3995 (5)0.1653 (6)0.0420 (13)
O3B0.6932 (3)0.4104 (3)0.2403 (3)0.0284 (7)
O4B0.5292 (4)0.4599 (5)0.1905 (6)0.0818 (17)
O50.3163 (3)0.4669 (3)0.1357 (5)0.0475 (10)
H5A0.38210.45180.14690.071*
H5B0.30560.49860.21070.071*
O60.7698 (4)0.7853 (3)0.5047 (6)0.0744 (17)
H6A0.75980.82980.44040.112*
H6B0.82820.80380.54490.112*
O70.6130 (6)0.6865 (6)0.2363 (8)0.117 (3)
H7A0.65560.69470.17280.175*
H7B0.58930.62400.22370.175*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Co10.0306 (4)0.0164 (3)0.0212 (3)0.0002 (2)0.0019 (2)0.0009 (2)
K10.0616 (9)0.0277 (6)0.0415 (7)0.0043 (5)0.0062 (6)0.0053 (5)
O1A0.035 (2)0.0226 (16)0.0199 (16)0.0018 (13)0.0024 (13)0.0001 (12)
O2A0.042 (2)0.0193 (16)0.0327 (19)0.0008 (14)0.0092 (15)0.0028 (13)
C1A0.032 (3)0.015 (2)0.032 (3)0.0003 (17)0.002 (2)0.0051 (17)
C2A0.031 (3)0.024 (2)0.033 (3)0.0026 (19)0.002 (2)0.0043 (19)
N1A0.032 (2)0.0168 (18)0.030 (2)0.0001 (15)0.0011 (16)0.0032 (15)
C3A0.039 (3)0.027 (3)0.032 (3)0.004 (2)0.004 (2)0.0046 (19)
C4A0.038 (3)0.024 (2)0.020 (2)0.0022 (19)0.0010 (19)0.0003 (17)
O3A0.0326 (18)0.0143 (15)0.0314 (17)0.0007 (13)0.0054 (13)0.0015 (12)
O4A0.050 (2)0.0215 (17)0.0269 (17)0.0100 (14)0.0040 (15)0.0047 (13)
O1B0.0363 (19)0.0179 (15)0.0264 (17)0.0028 (13)0.0012 (14)0.0012 (12)
O2B0.067 (3)0.049 (3)0.048 (2)0.031 (2)0.010 (2)0.0141 (19)
C1B0.036 (3)0.043 (3)0.027 (3)0.001 (2)0.003 (2)0.006 (2)
C2B0.053 (4)0.060 (4)0.034 (3)0.004 (3)0.003 (3)0.007 (3)
N1B0.034 (2)0.034 (2)0.023 (2)0.0099 (17)0.0005 (17)0.0001 (16)
C3B0.065 (4)0.044 (3)0.046 (4)0.001 (3)0.024 (3)0.001 (3)
C4B0.032 (3)0.055 (3)0.039 (3)0.000 (3)0.004 (2)0.004 (3)
O3B0.0293 (18)0.0288 (18)0.0268 (17)0.0038 (14)0.0012 (14)0.0045 (13)
O4B0.040 (3)0.123 (5)0.081 (4)0.019 (3)0.007 (2)0.016 (3)
O50.035 (2)0.055 (3)0.051 (2)0.0017 (18)0.0079 (18)0.0020 (19)
O60.066 (3)0.035 (2)0.116 (4)0.007 (2)0.046 (3)0.018 (3)
O70.117 (6)0.103 (5)0.124 (6)0.045 (4)0.050 (5)0.035 (4)
Geometric parameters (Å, º) top
Co1—O1B1.886 (3)C3A—H32A0.9900
Co1—O3A1.899 (3)C4A—O4A1.245 (6)
Co1—N1A1.902 (4)C4A—O3A1.282 (6)
Co1—N1B1.909 (4)O1B—C1B1.278 (6)
Co1—O3B1.917 (3)O2B—C1B1.226 (7)
Co1—O1A1.921 (3)O2B—K1iii2.862 (4)
K1—O3B2.759 (3)C1B—C2B1.565 (8)
K1—O62.766 (4)C2B—C3B1.472 (9)
K1—O72.799 (6)C2B—N1B1.506 (8)
K1—O2Ai2.821 (4)C2B—H21B1.0000
K1—O2Bii2.862 (4)N1B—H11B0.9200
K1—O3A3.078 (4)N1B—H12B0.9200
K1—O1A3.092 (3)C3B—C4B1.456 (8)
O1A—C1A1.286 (6)C3B—H31B0.9900
O2A—C1A1.221 (6)C3B—H32B0.9900
O2A—K1i2.821 (4)C4B—O4B1.258 (8)
C1A—C2A1.549 (7)C4B—O3B1.279 (6)
C2A—N1A1.486 (6)O5—H5A0.8434
C2A—C3A1.518 (6)O5—H5B0.8445
C2A—H21A1.0000O6—H6A0.8397
N1A—H11A0.9200O6—H6B0.8406
N1A—H12A0.9200O7—H7A0.8400
C3A—C4A1.512 (7)O7—H7B0.8400
C3A—H31A0.9900Co1—K13.6502 (14)
O1B—Co1—O3A177.34 (14)C2A—N1A—H12A110.7
O1B—Co1—N1A89.62 (16)Co1—N1A—H12A110.7
O3A—Co1—N1A91.48 (16)H11A—N1A—H12A108.8
O1B—Co1—N1B86.38 (15)C4A—C3A—C2A115.8 (4)
O3A—Co1—N1B91.08 (15)C4A—C3A—H31A108.3
N1A—Co1—N1B97.02 (18)C2A—C3A—H31A108.3
O1B—Co1—O3B92.85 (15)C4A—C3A—H32A108.3
O3A—Co1—O3B86.27 (14)C2A—C3A—H32A108.3
N1A—Co1—O3B174.29 (15)H31A—C3A—H32A107.4
N1B—Co1—O3B88.27 (16)O4A—C4A—O3A121.2 (4)
O1B—Co1—O1A90.54 (13)O4A—C4A—C3A116.9 (4)
O3A—Co1—O1A91.97 (13)O3A—C4A—C3A121.9 (4)
N1A—Co1—O1A84.57 (15)C4A—O3A—Co1128.3 (3)
N1B—Co1—O1A176.52 (15)C4A—O3A—K1110.2 (3)
O3B—Co1—O1A90.26 (14)Co1—O3A—K191.21 (12)
O3B—K1—O6154.90 (14)C1B—O1B—Co1116.2 (3)
O3B—K1—O780.32 (15)C1B—O2B—K1iii124.5 (3)
O6—K1—O775.45 (17)O2B—C1B—O1B124.4 (5)
O3B—K1—O2Ai119.60 (11)O2B—C1B—C2B123.5 (5)
O6—K1—O2Ai71.88 (12)O1B—C1B—C2B112.0 (5)
O7—K1—O2Ai126.7 (2)C3B—C2B—N1B105.7 (5)
O3B—K1—O2Bii81.86 (12)C3B—C2B—C1B112.6 (5)
O6—K1—O2Bii118.22 (16)N1B—C2B—C1B108.1 (4)
O7—K1—O2Bii127.1 (2)C3B—C2B—H21B110.1
O2Ai—K1—O2Bii105.39 (12)N1B—C2B—H21B110.1
O3B—K1—O3A52.76 (9)C1B—C2B—H21B110.1
O6—K1—O3A118.15 (15)C2B—N1B—Co1104.3 (3)
O7—K1—O3A85.84 (18)C2B—N1B—H11B110.9
O2Ai—K1—O3A74.34 (10)Co1—N1B—H11B110.9
O2Bii—K1—O3A119.93 (11)C2B—N1B—H12B110.9
O3B—K1—O1A55.06 (9)Co1—N1B—H12B110.9
O6—K1—O1A143.04 (13)H11B—N1B—H12B108.9
O7—K1—O1A131.14 (15)C4B—C3B—C2B117.6 (5)
O2Ai—K1—O1A71.27 (9)C4B—C3B—H31B107.9
O2Bii—K1—O1A69.84 (10)C2B—C3B—H31B107.9
O3A—K1—O1A52.89 (8)C4B—C3B—H32B107.9
C1A—O1A—Co1114.1 (3)C2B—C3B—H32B107.9
C1A—O1A—K1115.3 (3)H31B—C3B—H32B107.2
Co1—O1A—K190.35 (11)O4B—C4B—O3B117.5 (5)
C1A—O2A—K1i129.0 (3)O4B—C4B—C3B118.6 (5)
O2A—C1A—O1A125.0 (5)O3B—C4B—C3B123.9 (5)
O2A—C1A—C2A121.9 (4)C4B—O3B—Co1125.1 (3)
O1A—C1A—C2A113.1 (4)C4B—O3B—K1128.7 (3)
N1A—C2A—C3A109.1 (4)Co1—O3B—K1101.11 (13)
N1A—C2A—C1A107.4 (4)H5A—O5—H5B100.9
C3A—C2A—C1A111.2 (4)K1—O6—H6A114.0
N1A—C2A—H21A109.7K1—O6—H6B117.1
C3A—C2A—H21A109.7H6A—O6—H6B104.8
C1A—C2A—H21A109.7K1—O7—H7A98.0
C2A—N1A—Co1105.1 (3)K1—O7—H7B80.1
C2A—N1A—H11A110.7H7A—O7—H7B103.8
Co1—N1A—H11A110.7
O2A—C1A—C2A—N1A154.3 (4)O2B—C1B—C2B—N1B153.2 (5)
O1A—C1A—C2A—N1A25.2 (5)O1B—C1B—C2B—N1B27.4 (6)
O2A—C1A—C2A—C3A86.4 (5)O2B—C1B—C2B—C3B90.5 (7)
O1A—C1A—C2A—C3A94.1 (5)O1B—C1B—C2B—C3B89.0 (6)
N1A—C2A—C3A—C4A50.6 (6)N1B—C2B—C3B—C4B45.0 (7)
C1A—C2A—C3A—C4A67.7 (5)C1B—C2B—C3B—C4B72.8 (7)
C2A—C3A—C4A—O4A177.9 (4)C2B—C3B—C4B—O4B172.2 (6)
C2A—C3A—C4A—O3A2.3 (7)C2B—C3B—C4B—O3B7.7 (9)
Symmetry codes: (i) x+2, y+1, z+1; (ii) x, y+1/2, z+1/2; (iii) x, y+1/2, z1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1A—H11A···O2Aiii0.922.292.930 (5)126
N1A—H11A···O4Aiv0.922.323.011 (5)131
N1A—H12A···O4Av0.922.062.981 (5)177
N1B—H11B···O5vi0.922.042.942 (6)168
N1B—H12B···O1Biii0.922.342.925 (5)121
N1B—H12B···O1Aiii0.922.493.166 (5)130
O5—H5A···O4B0.841.872.685 (6)163
O5—H5B···O2Bvii0.841.942.777 (6)169
O6—H6A···O5vii0.842.072.826 (6)149
O6—H6B···O4Aviii0.842.082.914 (6)174
O7—H7A···O6ix0.842.233.074 (11)17
O7—H7B···O4B0.842.203.038 (10)179
C2B—H21B···O3Biii1.002.483.419 (7)156
C3A—H32A···O5x0.992.593.328 (7)132
Symmetry codes: (iii) x, y+1/2, z1/2; (iv) x+2, y1/2, 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, z1/2; (x) x+1, y, z.

Experimental details

Crystal data
Chemical formulaK[Co(C4H5NO4)2]·3.5H2O
Mr423.27
Crystal system, space groupMonoclinic, P21/c
Temperature (K)120
a, b, c (Å)12.4853 (13), 12.4689 (13), 9.6914 (8)
β (°) 92.952 (7)
V3)1506.7 (3)
Z4
Radiation typeMo Kα
µ (mm1)1.48
Crystal size (mm)0.40 × 0.30 × 0.08
Data collection
DiffractometerNonius KappaCCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.517, 0.891
No. of measured, independent and
observed [I > 2σ(I)] reflections
16788, 3330, 2568
Rint0.045
(sin θ/λ)max1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.065, 0.175, 1.09
No. of reflections3330
No. of parameters208
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)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).

Selected geometric parameters (Å, º) top
Co1—O1B1.886 (3)K1—O62.766 (4)
Co1—O3A1.899 (3)K1—O72.799 (6)
Co1—N1A1.902 (4)K1—O2Ai2.821 (4)
Co1—N1B1.909 (4)K1—O2Bii2.862 (4)
Co1—O3B1.917 (3)K1—O3A3.078 (4)
Co1—O1A1.921 (3)K1—O1A3.092 (3)
K1—O3B2.759 (3)
O1B—Co1—O3A177.34 (14)N1A—Co1—O3B174.29 (15)
O1B—Co1—N1A89.62 (16)N1B—Co1—O3B88.27 (16)
O3A—Co1—N1A91.48 (16)O1B—Co1—O1A90.54 (13)
O1B—Co1—N1B86.38 (15)O3A—Co1—O1A91.97 (13)
O3A—Co1—N1B91.08 (15)N1A—Co1—O1A84.57 (15)
N1A—Co1—N1B97.02 (18)N1B—Co1—O1A176.52 (15)
O1B—Co1—O3B92.85 (15)O3B—Co1—O1A90.26 (14)
O3A—Co1—O3B86.27 (14)
N1A—C2A—C3A—C4A50.6 (6)N1B—C2B—C3B—C4B45.0 (7)
C1A—C2A—C3A—C4A67.7 (5)C1B—C2B—C3B—C4B72.8 (7)
Symmetry codes: (i) x+2, y+1, z+1; (ii) x, y+1/2, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1A—H11A···O2Aiii0.922.292.930 (5)126
N1A—H11A···O4Aiv0.922.323.011 (5)131
N1A—H12A···O4Av0.922.062.981 (5)177
N1B—H11B···O5vi0.922.042.942 (6)168
N1B—H12B···O1Biii0.922.342.925 (5)121
N1B—H12B···O1Aiii0.922.493.166 (5)130
O5—H5A···O4B0.841.872.685 (6)163
O5—H5B···O2Bvii0.841.942.777 (6)169
O6—H6A···O5vii0.842.072.826 (6)149
O6—H6B···O4Aviii0.842.082.914 (6)174
O7—H7A···O6ix0.842.233.074 (11)17
O7—H7B···O4B0.842.203.038 (10)179
C2B—H21B···O3Biii1.002.483.419 (7)156
C3A—H32A···O5x0.992.593.328 (7)132
Symmetry codes: (iii) x, y+1/2, z1/2; (iv) x+2, y1/2, 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, z1/2; (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

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