metal-organic compounds
(2-Amino-7-methyl-4-oxidopteridine-6-carboxylato-κ3O4,N5,O6)aqua(1,10-phenanthroline-κ2N,N′)cobalt(II) trihydrate
aDepartment of Chemistry, University of North Bengal, Siliguri 734 013, India
*Correspondence e-mail: psrnbu@gmail.com
In the title compound, [Co(C8H5N5O3)(C12H8N2)(H2O)]·3H2O, a tridentate 2-amino-7-methyl-4-oxidopteridine-6-carboxylate ligand, a bidentate ancillary 1,10-phenanthroline (phen) ligand and a water molecule complete a distorted octahedral geometry around the CoII atom. The pterin ligand forms two chelate rings. The phen and pterin ring systems are nearly perpendicular [dihedral angle = 85.15 (8)°]. N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds link the complex molecules and lattice water molecules into a layer parallel to (001). π–π stacking contacts (involving phen–phen and pteridine–pteridine) are also observed [centroid–centroid distances = 3.670 (2), 3.547 (2), 3.698 (2) and 3.349 (2) Å].
Related literature
For background to the chemistry of pterins in metalloenzymes, see: Basu & Burgmayer (2011); Burgmayer (1998); Fitzpatrick (2003); Fukuzumi & Kojima (2008). For structures of related cobalt complexes, see: Acuña-Cueva et al. (2003); Beddoes et al. (1997); Burgmayer & Stiefel (1988); Funahashi et al. (1997). For structures of related copper complexes, see: Odani et al. (1992). For the electron-shuffling ability of the pterin unit as well as its donor groups and the effect on the geometric parameters of related complexes, see: Beddoes et al. (1993); Kohzuma et al. (1988); Russell et al. (1992). For the synthesis of the pterin ligand, see: Wittle et al. (1947).
Experimental
Crystal data
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Refinement
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Data collection: APEX2 (Bruker, 2007); cell SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS.
Supporting information
https://doi.org/10.1107/S1600536812051185/hy2609sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812051185/hy2609Isup2.hkl
2-Amino-4-hydroxy-7-methylpteridine-6-carboxylic acid sesquihydrate (C8H7N5O3.1.5H2O) was obtained by published procedure (Wittle et al., 1947). The title complex was prepared by the dropwise addition of an aqueous alkaline solution (NaOH: 11 mg, 0.275 mmol) of the pterin ligand (31 mg, 0.125 mmol) to a warm (311 K) aqueous reaction medium containing CoSO4.7H2O (35 mg, 0.125 mmol) and 1,10-phenanthroline monohydrate (25 mg, 0.125 mmol) in a total volume of 60 ml. The pH value was adjusted to 10.8 using aqueous NaOH solution and dioxygen was bubbled in for 48 h; final pH was 10.3. Initially a small amount of yellow-white precipitate came out and the reaction mixture ultimately assumed a reddish-pink tinge. It was transferred to a 100 ml beaker, requisite quantity of water was added to make up for the evaporation loss and allowed to stand at room temperature. Pink crystals suitable for single-crystal X-ray diffraction appeared after 15 days (yield: 30%).
The H atoms were all located in a difference map, but those attached to C atoms were repositioned geometrically. The H atoms were initially refined with soft restrains on the bond lengths and angles to regularize their geometry (C—H = 0.93–0.98, N—H = 0.86–0.89, O—H = 0.82 Å) and with Uiso(H) = 1.2–1.5Ueq(parent atom), after which the positions were refined with rigiding constrains.
The primary motivation for pursuing coordination chemistry of pterins is the ubiquitous presence of this heterocyclic system in nature including a substantial number of metalloenzymes (Basu & Burgmayer, 2011; Burgmayer, 1998; Fitzpatrick, 2003; Fukuzumi & Kojima, 2008). Literature survey reveals the existence of only a few X-ray structurally characterized cobalt-pterin/pteridine/lumazine complexes as well as one containing an organocobalt moiety (Acuña-Cueva et al., 2003; Beddoes et al., 1997; Burgmayer & Stiefel, 1988; Funahashi et al., 1997). The concerned ligands usually act as bidentate O,N-donors and none of the above complexes possesses a typical π-acceptor ancillary ligand like 1,10-phenanthroline (phen). In this crystallographic study on the title cobalt(II) complex, possessing both a tridentate pterin ligand and a π-acidic ligand like phen, different aspects are considered, e.g. crystal, molecular and electronic structures.
In the title compound (Fig. 1), the stereochemistry around the CoII atom is essentially distorted octahedral with two N atoms of phen, a pyrazine ring N atom (N3) of the pterin ligand and an aqua O atom forming the equatorial plane; two pterin O atoms (O1 and O3) define the longer axial positions, with the phenolate O3 forming the longest axial bond [2.270 (2) Å]. Extent of distortion of this coordination octahedron is much more pronounced as compared to that of the Co(II)-pteridine complexes reported earlier (Acuña-Cueva et al., 2003; Burgmayer & Stiefel, 1988; Funahashi et al., 1997). A major cause of this departure from regular geometry is that the pterin ligand forms two five-membered chelate rings having small bite angles [75.10 (10) and 76.26 (9)°], instead of only one per pteridine ligand for the earlier cases. Location of the short Co1—N3 bond [2.016 (3) Å] in the equatorial plane is consistent with the literature, which suggests a strong cobalt-pterin interaction (Odani et al., 1992). The pterin ligand is coordinated here as a binegative tridentate ONO donor, as evident from the charge balance of this complex. The phen and pterin rings are nearly perpendicular to each other for minimizing the steric repulsion. The Co1—N1 [2.079 (3) Å] and Co1—N2 [2.123 (3) Å] bond lengths are at par with that of the Co1—N3 bond [2.016 (3) Å] and indicate receipt of π-back donation to both phen and pterin rings from the Co(II) centre (d7) through dπ–pπ interactions. This process is further strengthened by the presence of π-donating phenolate and carboxylate O atoms around the metal centre (Kohzuma et al., 1988).
For rationalizing the near double bond nature of the O3—C18 [1.265 (4) Å] bond, a hypothesis of Joule (Beddoes et al., 1993; Russell et al., 1992) may be invoked, which suggests withdrawl of electron density from the pyrazine ring N6 by the pyrimidine ring C18-carbonyl group through mesomeric interaction. Formation of the O3—Co1 bond accentuates this electron withdrawal towards O3. The electron-rich N7—C17 [1.337 (4) Å] bond may also participate in this
The pyrimidine ring is fairly planer and deviations of the C16/N5/C17 and C17/N4/C18 segments with respect to the N7—C17 multiple bonds are 2.6 and 0.7°, respectively.In the crystal, intermolecular N—H···O, O—H···N and O—H···O hydrogen bonds (Table 1) link the complex molecules and lattice water molecules into a layer parallel to (001) (Fig. 2). The lattice water molecules are decisive for the crystal packing. Fig. 3 reveals π–π stacking interactions involving two parallel, inversion-related pterin rings within the same and showing face-to-face distance of 3.283 (4) and 3.366 (4) Å. Again the phen rings display two types of π–π stacking on either side of the In one case, the adjacent phen rings are essentially parallel to each other with an average interplanar distance of 3.496 (4) Å; on the other side of the the face-to-face seperations between parallel phen rings are 3.578 (4) and 3.629 (5) Å.
For background to the chemistry of pterins in metalloenzymes, see: Basu & Burgmayer (2011); Burgmayer (1998); Fitzpatrick (2003); Fukuzumi & Kojima (2008). For structures of related cobalt complexes, see: Acuña-Cueva et al. (2003); Beddoes et al. (1997); Burgmayer & Stiefel (1988); Funahashi et al. (1997). For structures of related copper complexes, see: Odani et al. (1992). For the electron-shuffling ability of the pterin unit as well as its donor groups and the affect on the geometric parameters of related complexes, see: Beddoes et al. (1993); Kohzuma et al. (1988); Russell et al. (1992). For the synthesis and nomenclature of the pterin ligand, see: Wittle et al. (1947).
Data collection: APEX2 (Bruker, 2007); cell
SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS (Betteridge et al., 2003).Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. Lattice water molecules are omitted for clarity. | |
Fig. 2. The crystal packing diagram of the title compound, viewed along the b axis. Dotted lines indicate hydrogen bonds, assisting the formation of a layer structure parallel to (001). | |
Fig. 3. A molecular packing diagram highlighting π–π stacking interactions between two neighbouring phen–phen and pterin–pterin rings, respectively. |
[Co(C8H5N5O3)(C12H8N2)(H2O)]·3H2O | Z = 2 |
Mr = 530.36 | F(000) = 546 |
Triclinic, P1 | Dx = 1.659 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 8.454 (2) Å | Cell parameters from 8945 reflections |
b = 9.934 (3) Å | θ = 2–28° |
c = 13.778 (4) Å | µ = 0.87 mm−1 |
α = 97.534 (4)° | T = 110 K |
β = 95.281 (4)° | Block, pink |
γ = 110.603 (4)° | 0.23 × 0.11 × 0.04 mm |
V = 1061.8 (5) Å3 |
Bruker Kappa APEXII CCD diffractometer | 4360 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
φ and ω scans | θmax = 28.2°, θmin = 1.5° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −11→11 |
Tmin = 0.82, Tmax = 0.97 | k = −12→13 |
8945 measured reflections | l = −18→18 |
4726 independent reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Hydrogen site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.057 | H-atom parameters constrained |
wR(F2) = 0.129 | Method = Modified Sheldrick w = 1/[σ2(F2) + ( 0.04P)2 + 3.34P], where P = (max(Fo2,0) + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max = 0.0001859 |
4726 reflections | Δρmax = 0.99 e Å−3 |
316 parameters | Δρmin = −0.88 e Å−3 |
0 restraints |
[Co(C8H5N5O3)(C12H8N2)(H2O)]·3H2O | γ = 110.603 (4)° |
Mr = 530.36 | V = 1061.8 (5) Å3 |
Triclinic, P1 | Z = 2 |
a = 8.454 (2) Å | Mo Kα radiation |
b = 9.934 (3) Å | µ = 0.87 mm−1 |
c = 13.778 (4) Å | T = 110 K |
α = 97.534 (4)° | 0.23 × 0.11 × 0.04 mm |
β = 95.281 (4)° |
Bruker Kappa APEXII CCD diffractometer | 4726 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 4360 reflections with I > 2σ(I) |
Tmin = 0.82, Tmax = 0.97 | Rint = 0.030 |
8945 measured reflections |
R[F2 > 2σ(F2)] = 0.057 | 0 restraints |
wR(F2) = 0.129 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.99 e Å−3 |
4726 reflections | Δρmin = −0.88 e Å−3 |
316 parameters |
x | y | z | Uiso*/Ueq | ||
Co1 | 0.45982 (5) | 0.22172 (4) | 0.22887 (3) | 0.0125 | |
O1 | 0.2062 (3) | 0.0747 (2) | 0.23341 (17) | 0.0176 | |
C13 | 0.1224 (4) | 0.1182 (3) | 0.2948 (2) | 0.0159 | |
O2 | −0.0205 (3) | 0.0408 (2) | 0.31159 (18) | 0.0204 | |
C14 | 0.2096 (4) | 0.2762 (3) | 0.3463 (2) | 0.0150 | |
N3 | 0.3618 (3) | 0.3367 (3) | 0.32052 (19) | 0.0137 | |
C19 | 0.4572 (4) | 0.4746 (3) | 0.3559 (2) | 0.0137 | |
C16 | 0.4012 (4) | 0.5628 (3) | 0.4205 (2) | 0.0151 | |
N5 | 0.4986 (3) | 0.7057 (3) | 0.4529 (2) | 0.0154 | |
C17 | 0.6493 (4) | 0.7539 (3) | 0.4170 (2) | 0.0157 | |
N4 | 0.7169 (3) | 0.6739 (3) | 0.3559 (2) | 0.0161 | |
C18 | 0.6243 (4) | 0.5321 (3) | 0.3254 (2) | 0.0148 | |
O3 | 0.6704 (3) | 0.4463 (2) | 0.26886 (17) | 0.0174 | |
N7 | 0.7460 (4) | 0.8957 (3) | 0.4440 (2) | 0.0199 | |
H141 | 0.8293 | 0.9343 | 0.4135 | 0.0223* | |
H142 | 0.7086 | 0.9522 | 0.4775 | 0.0228* | |
N6 | 0.2466 (3) | 0.5028 (3) | 0.4504 (2) | 0.0176 | |
C15 | 0.1508 (4) | 0.3621 (3) | 0.4146 (2) | 0.0171 | |
C20 | −0.0163 (4) | 0.2992 (4) | 0.4506 (3) | 0.0256 | |
H172 | −0.0359 | 0.3696 | 0.4963 | 0.0378* | |
H173 | −0.0185 | 0.2188 | 0.4829 | 0.0383* | |
H171 | −0.1061 | 0.2680 | 0.3985 | 0.0380* | |
O4 | 0.5538 (3) | 0.1469 (2) | 0.35063 (17) | 0.0185 | |
H181 | 0.4964 | 0.0663 | 0.3597 | 0.0272* | |
H182 | 0.5418 | 0.1894 | 0.4013 | 0.0271* | |
N2 | 0.3758 (3) | 0.2801 (3) | 0.0963 (2) | 0.0162 | |
C12 | 0.2567 (4) | 0.3370 (4) | 0.0798 (3) | 0.0196 | |
C11 | 0.2191 (4) | 0.3750 (4) | −0.0116 (3) | 0.0230 | |
C10 | 0.3071 (4) | 0.3548 (4) | −0.0867 (3) | 0.0220 | |
C8 | 0.4354 (4) | 0.2958 (4) | −0.0719 (2) | 0.0183 | |
C9 | 0.4634 (4) | 0.2593 (3) | 0.0218 (2) | 0.0138 | |
C5 | 0.5897 (4) | 0.1963 (3) | 0.0422 (2) | 0.0147 | |
N1 | 0.6075 (3) | 0.1592 (3) | 0.1330 (2) | 0.0152 | |
C1 | 0.7247 (4) | 0.1018 (3) | 0.1537 (2) | 0.0178 | |
C2 | 0.8260 (4) | 0.0749 (4) | 0.0839 (3) | 0.0225 | |
C3 | 0.8069 (4) | 0.1096 (4) | −0.0079 (3) | 0.0221 | |
C4 | 0.6854 (4) | 0.1721 (3) | −0.0323 (2) | 0.0179 | |
C6 | 0.6545 (4) | 0.2115 (4) | −0.1271 (3) | 0.0227 | |
C7 | 0.5346 (5) | 0.2690 (4) | −0.1461 (3) | 0.0241 | |
H321 | 0.5124 | 0.2898 | −0.2083 | 0.0280* | |
H311 | 0.7136 | 0.1926 | −0.1771 | 0.0268* | |
H291 | 0.8704 | 0.0898 | −0.0554 | 0.0258* | |
H281 | 0.9086 | 0.0377 | 0.1020 | 0.0257* | |
H271 | 0.7401 | 0.0814 | 0.2171 | 0.0208* | |
H221 | 0.2815 | 0.3779 | −0.1477 | 0.0263* | |
H211 | 0.1346 | 0.4115 | −0.0211 | 0.0270* | |
H201 | 0.1976 | 0.3531 | 0.1304 | 0.0229* | |
O7 | 0.9931 (4) | 0.4695 (3) | 0.1919 (3) | 0.0445 | |
H331 | 1.0355 | 0.5568 | 0.1993 | 0.0644* | |
H332 | 0.9309 | 0.4819 | 0.2305 | 0.0648* | |
O5 | 0.0341 (3) | −0.2327 (3) | 0.28207 (18) | 0.0224 | |
H341 | 0.0418 | −0.1559 | 0.2637 | 0.0322* | |
H342 | −0.0472 | −0.2571 | 0.3124 | 0.0321* | |
O6 | 0.3374 (3) | −0.0951 (2) | 0.40693 (18) | 0.0204 | |
H351 | 0.2468 | −0.1420 | 0.3696 | 0.0287* | |
H352 | 0.3795 | −0.1552 | 0.4182 | 0.0294* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Co1 | 0.0135 (2) | 0.0131 (2) | 0.0129 (2) | 0.00622 (16) | 0.00458 (15) | 0.00324 (15) |
O1 | 0.0164 (11) | 0.0142 (11) | 0.0210 (12) | 0.0040 (9) | 0.0048 (9) | 0.0026 (9) |
C13 | 0.0156 (15) | 0.0157 (15) | 0.0168 (15) | 0.0064 (12) | −0.0002 (12) | 0.0050 (12) |
O2 | 0.0143 (11) | 0.0173 (11) | 0.0269 (13) | 0.0015 (9) | 0.0059 (9) | 0.0056 (10) |
C14 | 0.0134 (14) | 0.0150 (15) | 0.0185 (15) | 0.0062 (12) | 0.0048 (12) | 0.0053 (12) |
N3 | 0.0134 (12) | 0.0130 (12) | 0.0153 (13) | 0.0049 (10) | 0.0035 (10) | 0.0038 (10) |
C19 | 0.0139 (14) | 0.0141 (14) | 0.0156 (15) | 0.0062 (12) | 0.0053 (12) | 0.0057 (12) |
C16 | 0.0158 (15) | 0.0172 (15) | 0.0152 (15) | 0.0085 (12) | 0.0029 (12) | 0.0050 (12) |
N5 | 0.0149 (13) | 0.0129 (12) | 0.0196 (14) | 0.0060 (10) | 0.0040 (10) | 0.0030 (10) |
C17 | 0.0157 (15) | 0.0175 (15) | 0.0167 (15) | 0.0083 (12) | 0.0030 (12) | 0.0063 (12) |
N4 | 0.0150 (13) | 0.0148 (13) | 0.0202 (14) | 0.0057 (10) | 0.0078 (11) | 0.0047 (11) |
C18 | 0.0144 (15) | 0.0169 (15) | 0.0150 (15) | 0.0065 (12) | 0.0036 (12) | 0.0063 (12) |
O3 | 0.0173 (11) | 0.0170 (11) | 0.0193 (12) | 0.0073 (9) | 0.0065 (9) | 0.0028 (9) |
N7 | 0.0188 (14) | 0.0136 (13) | 0.0264 (15) | 0.0044 (11) | 0.0081 (12) | 0.0020 (11) |
N6 | 0.0164 (13) | 0.0169 (13) | 0.0224 (14) | 0.0083 (11) | 0.0071 (11) | 0.0041 (11) |
C15 | 0.0148 (15) | 0.0171 (15) | 0.0226 (16) | 0.0075 (12) | 0.0065 (12) | 0.0079 (13) |
C20 | 0.0163 (16) | 0.0207 (17) | 0.040 (2) | 0.0056 (14) | 0.0126 (15) | 0.0024 (15) |
O4 | 0.0198 (12) | 0.0193 (11) | 0.0174 (11) | 0.0069 (9) | 0.0052 (9) | 0.0063 (9) |
N2 | 0.0151 (13) | 0.0150 (13) | 0.0203 (14) | 0.0061 (10) | 0.0063 (11) | 0.0055 (11) |
C12 | 0.0169 (16) | 0.0171 (15) | 0.0263 (18) | 0.0064 (13) | 0.0075 (13) | 0.0055 (13) |
C11 | 0.0193 (17) | 0.0195 (16) | 0.0319 (19) | 0.0082 (14) | 0.0003 (14) | 0.0098 (14) |
C10 | 0.0202 (17) | 0.0232 (17) | 0.0224 (17) | 0.0061 (14) | −0.0007 (13) | 0.0107 (14) |
C8 | 0.0177 (16) | 0.0168 (15) | 0.0178 (16) | 0.0030 (12) | 0.0007 (12) | 0.0044 (13) |
C9 | 0.0133 (14) | 0.0114 (14) | 0.0153 (15) | 0.0026 (11) | 0.0032 (11) | 0.0022 (11) |
C5 | 0.0129 (14) | 0.0113 (14) | 0.0176 (15) | 0.0020 (11) | 0.0022 (12) | 0.0015 (12) |
N1 | 0.0152 (13) | 0.0133 (12) | 0.0158 (13) | 0.0040 (10) | 0.0034 (10) | 0.0013 (10) |
C1 | 0.0171 (15) | 0.0150 (15) | 0.0199 (16) | 0.0058 (12) | 0.0002 (12) | 0.0005 (12) |
C2 | 0.0169 (16) | 0.0214 (17) | 0.0312 (19) | 0.0103 (14) | 0.0035 (14) | 0.0025 (14) |
C3 | 0.0162 (16) | 0.0190 (16) | 0.0298 (19) | 0.0059 (13) | 0.0079 (14) | −0.0016 (14) |
C4 | 0.0152 (15) | 0.0162 (15) | 0.0200 (16) | 0.0032 (12) | 0.0055 (13) | 0.0009 (13) |
C6 | 0.0241 (17) | 0.0251 (17) | 0.0181 (17) | 0.0072 (14) | 0.0093 (14) | 0.0026 (14) |
C7 | 0.0299 (19) | 0.0254 (18) | 0.0169 (16) | 0.0070 (15) | 0.0085 (14) | 0.0086 (14) |
O7 | 0.0352 (16) | 0.0272 (15) | 0.074 (2) | 0.0127 (13) | 0.0292 (16) | −0.0010 (15) |
O5 | 0.0178 (11) | 0.0184 (12) | 0.0318 (14) | 0.0057 (9) | 0.0095 (10) | 0.0059 (10) |
O6 | 0.0192 (12) | 0.0166 (11) | 0.0266 (13) | 0.0077 (9) | 0.0020 (10) | 0.0060 (10) |
Co1—O1 | 2.140 (2) | N2—C12 | 1.333 (4) |
Co1—N3 | 2.016 (3) | N2—C9 | 1.355 (4) |
Co1—O3 | 2.270 (2) | C12—C11 | 1.402 (5) |
Co1—O4 | 2.120 (2) | C12—H201 | 0.923 |
Co1—N2 | 2.123 (3) | C11—C10 | 1.363 (5) |
Co1—N1 | 2.079 (3) | C11—H211 | 0.914 |
O1—C13 | 1.279 (4) | C10—C8 | 1.414 (5) |
C13—O2 | 1.244 (4) | C10—H221 | 0.926 |
C13—C14 | 1.519 (4) | C8—C9 | 1.408 (4) |
C14—N3 | 1.319 (4) | C8—C7 | 1.435 (5) |
C14—C15 | 1.426 (4) | C9—C5 | 1.439 (4) |
N3—C19 | 1.319 (4) | C5—N1 | 1.359 (4) |
C19—C16 | 1.397 (4) | C5—C4 | 1.411 (4) |
C19—C18 | 1.450 (4) | N1—C1 | 1.333 (4) |
C16—N5 | 1.354 (4) | C1—C2 | 1.406 (5) |
C16—N6 | 1.360 (4) | C1—H271 | 0.930 |
N5—C17 | 1.360 (4) | C2—C3 | 1.363 (5) |
C17—N4 | 1.378 (4) | C2—H281 | 0.928 |
C17—N7 | 1.337 (4) | C3—C4 | 1.412 (5) |
N4—C18 | 1.335 (4) | C3—H291 | 0.928 |
C18—O3 | 1.265 (4) | C4—C6 | 1.439 (5) |
N7—H141 | 0.852 | C6—C7 | 1.349 (5) |
N7—H142 | 0.843 | C6—H311 | 0.925 |
N6—C15 | 1.342 (4) | C7—H321 | 0.926 |
C15—C20 | 1.491 (4) | O7—H331 | 0.800 |
C20—H172 | 0.947 | O7—H332 | 0.810 |
C20—H173 | 0.960 | O5—H341 | 0.811 |
C20—H171 | 0.930 | O5—H342 | 0.820 |
O4—H181 | 0.810 | O6—H351 | 0.830 |
O4—H182 | 0.801 | O6—H352 | 0.820 |
O1—Co1—N3 | 75.10 (10) | H172—C20—H171 | 106.6 |
O1—Co1—O3 | 151.22 (8) | H173—C20—H171 | 109.7 |
N3—Co1—O3 | 76.26 (9) | Co1—O4—H181 | 116.6 |
O1—Co1—O4 | 90.13 (9) | Co1—O4—H182 | 109.7 |
N3—Co1—O4 | 90.23 (10) | H181—O4—H182 | 95.0 |
O3—Co1—O4 | 92.74 (9) | Co1—N2—C12 | 128.8 (2) |
O1—Co1—N2 | 90.99 (10) | Co1—N2—C9 | 112.7 (2) |
N3—Co1—N2 | 96.45 (10) | C12—N2—C9 | 118.5 (3) |
O3—Co1—N2 | 89.46 (9) | N2—C12—C11 | 122.3 (3) |
O4—Co1—N2 | 173.29 (10) | N2—C12—H201 | 119.1 |
O1—Co1—N1 | 119.55 (10) | C11—C12—H201 | 118.6 |
N3—Co1—N1 | 164.48 (10) | C12—C11—C10 | 119.6 (3) |
O3—Co1—N1 | 88.76 (9) | C12—C11—H211 | 120.2 |
O4—Co1—N1 | 94.58 (10) | C10—C11—H211 | 120.2 |
N2—Co1—N1 | 79.12 (10) | C11—C10—C8 | 119.9 (3) |
Co1—O1—C13 | 116.8 (2) | C11—C10—H221 | 120.1 |
O1—C13—O2 | 124.1 (3) | C8—C10—H221 | 120.0 |
O1—C13—C14 | 114.6 (3) | C10—C8—C9 | 116.7 (3) |
O2—C13—C14 | 121.2 (3) | C10—C8—C7 | 124.4 (3) |
C13—C14—N3 | 111.4 (3) | C9—C8—C7 | 118.9 (3) |
C13—C14—C15 | 129.9 (3) | C8—C9—N2 | 123.1 (3) |
N3—C14—C15 | 118.8 (3) | C8—C9—C5 | 120.1 (3) |
Co1—N3—C14 | 121.6 (2) | N2—C9—C5 | 116.8 (3) |
Co1—N3—C19 | 117.6 (2) | C9—C5—N1 | 117.5 (3) |
C14—N3—C19 | 120.8 (3) | C9—C5—C4 | 119.5 (3) |
N3—C19—C16 | 121.8 (3) | N1—C5—C4 | 123.0 (3) |
N3—C19—C18 | 117.4 (3) | Co1—N1—C5 | 113.6 (2) |
C16—C19—C18 | 120.7 (3) | Co1—N1—C1 | 127.6 (2) |
C19—C16—N5 | 120.8 (3) | C5—N1—C1 | 118.5 (3) |
C19—C16—N6 | 118.7 (3) | N1—C1—C2 | 122.0 (3) |
N5—C16—N6 | 120.4 (3) | N1—C1—H271 | 118.0 |
C16—N5—C17 | 115.1 (3) | C2—C1—H271 | 120.0 |
N5—C17—N4 | 127.9 (3) | C1—C2—C3 | 119.8 (3) |
N5—C17—N7 | 117.0 (3) | C1—C2—H281 | 119.3 |
N4—C17—N7 | 115.1 (3) | C3—C2—H281 | 120.9 |
C17—N4—C18 | 117.6 (3) | C2—C3—C4 | 119.9 (3) |
C19—C18—N4 | 117.7 (3) | C2—C3—H291 | 120.7 |
C19—C18—O3 | 118.1 (3) | C4—C3—H291 | 119.4 |
N4—C18—O3 | 124.2 (3) | C3—C4—C5 | 116.8 (3) |
Co1—O3—C18 | 110.63 (19) | C3—C4—C6 | 124.2 (3) |
C17—N7—H141 | 119.8 | C5—C4—C6 | 119.0 (3) |
C17—N7—H142 | 119.9 | C4—C6—C7 | 121.2 (3) |
H141—N7—H142 | 117.6 | C4—C6—H311 | 119.5 |
C16—N6—C15 | 119.0 (3) | C7—C6—H311 | 119.2 |
C14—C15—N6 | 120.8 (3) | C8—C7—C6 | 121.3 (3) |
C14—C15—C20 | 121.7 (3) | C8—C7—H321 | 118.4 |
N6—C15—C20 | 117.4 (3) | C6—C7—H321 | 120.3 |
C15—C20—H172 | 111.5 | H331—O7—H332 | 86.2 |
C15—C20—H173 | 110.1 | H341—O5—H342 | 108.7 |
H172—C20—H173 | 108.2 | H351—O6—H352 | 105.5 |
C15—C20—H171 | 110.7 |
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H141···O2i | 0.85 | 2.12 | 2.942 (4) | 163 |
N7—H142···O6ii | 0.84 | 2.15 | 2.970 (4) | 165 |
O4—H181···O6 | 0.81 | 1.93 | 2.717 (3) | 164 |
O4—H182···N5ii | 0.80 | 2.25 | 3.051 (4) | 176 |
O5—H341···O1 | 0.82 | 2.34 | 3.079 (4) | 151 |
O5—H341···O2 | 0.82 | 2.23 | 2.896 (4) | 139 |
O5—H342···N4iii | 0.82 | 2.04 | 2.844 (4) | 166 |
O6—H351···O5 | 0.83 | 1.92 | 2.740 (4) | 174 |
O6—H352···N5iv | 0.82 | 2.05 | 2.871 (4) | 176 |
O7—H331···O5i | 0.80 | 2.25 | 2.941 (4) | 145 |
O7—H332···O3 | 0.81 | 2.23 | 2.962 (5) | 151 |
Symmetry codes: (i) x+1, y+1, z; (ii) −x+1, −y+1, −z+1; (iii) x−1, y−1, z; (iv) x, y−1, z. |
Experimental details
Crystal data | |
Chemical formula | [Co(C8H5N5O3)(C12H8N2)(H2O)]·3H2O |
Mr | 530.36 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 110 |
a, b, c (Å) | 8.454 (2), 9.934 (3), 13.778 (4) |
α, β, γ (°) | 97.534 (4), 95.281 (4), 110.603 (4) |
V (Å3) | 1061.8 (5) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.87 |
Crystal size (mm) | 0.23 × 0.11 × 0.04 |
Data collection | |
Diffractometer | Bruker Kappa APEXII CCD |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.82, 0.97 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8945, 4726, 4360 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.665 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.057, 0.129, 1.03 |
No. of reflections | 4726 |
No. of parameters | 316 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.99, −0.88 |
Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), CRYSTALS (Betteridge et al., 2003), CAMERON (Watkin et al., 1996).
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H141···O2i | 0.85 | 2.12 | 2.942 (4) | 163 |
N7—H142···O6ii | 0.84 | 2.15 | 2.970 (4) | 165 |
O4—H181···O6 | 0.81 | 1.93 | 2.717 (3) | 164 |
O4—H182···N5ii | 0.80 | 2.25 | 3.051 (4) | 176 |
O5—H341···O1 | 0.82 | 2.34 | 3.079 (4) | 151 |
O5—H341···O2 | 0.82 | 2.23 | 2.896 (4) | 139 |
O5—H342···N4iii | 0.82 | 2.04 | 2.844 (4) | 166 |
O6—H351···O5 | 0.83 | 1.92 | 2.740 (4) | 174 |
O6—H352···N5iv | 0.82 | 2.05 | 2.871 (4) | 176 |
O7—H331···O5i | 0.80 | 2.25 | 2.941 (4) | 145 |
O7—H332···O3 | 0.81 | 2.23 | 2.962 (5) | 151 |
Symmetry codes: (i) x+1, y+1, z; (ii) −x+1, −y+1, −z+1; (iii) x−1, y−1, z; (iv) x, y−1, z. |
Acknowledgements
The authors express their gratitude to the UGC, New Delhi, for financial assistance (SAP–DRS program). Thanks are due to the CSMCRI, Bhavnagar, Gujrat, India, for the X-ray structural data and the University of North Bengal for infrastructure.
References
Acuña-Cueva, E. R., Faure, R., Illán-Cabeza, N. A., Jiménez-Pulido, S. B., Moreno-Carretero, M. N. & Quirós-Olozábal, M. (2003). Inorg. Chim. Acta, 342, 209–218. Google Scholar
Basu, P. & Burgmayer, S. J. N. (2011). Coord. Chem. Rev. 255, 1016–1038. Web of Science CrossRef CAS PubMed Google Scholar
Beddoes, R. L., Dinsmore, A., Helliwell, M., Garner, C. D. & Joule, J. A. (1997). Acta Cryst. C53, 213–215. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Beddoes, R. L., Russell, J. R., Garner, C. D. & Joule, J. A. (1993). Acta Cryst. C49, 1649–1652. CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
Betteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487. Web of Science CrossRef IUCr Journals Google Scholar
Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Burgmayer, S. J. N. (1998). Struct. Bond. 92, 67–119. CAS Google Scholar
Burgmayer, S. J. N. & Stiefel, E. I. (1988). Inorg. Chem. 27, 4059–4061. CSD CrossRef CAS Web of Science Google Scholar
Fitzpatrick, P. F. (2003). Biochemistry, 42, 14083–14091. Web of Science CrossRef PubMed CAS Google Scholar
Fukuzumi, S. & Kojima, T. (2008). J. Biol. Inorg. Chem. 13, 321–333. Web of Science CrossRef PubMed CAS Google Scholar
Funahashi, Y., Hara, Y., Masuda, H. & Yamauchi, O. (1997). Inorg. Chem. 36, 3869–3875. CSD CrossRef CAS Web of Science Google Scholar
Kohzuma, T., Odani, A., Morita, Y., Takani, M. & Yamauchi, O. (1988). Inorg. Chem. 27, 3854–3858. CrossRef CAS Web of Science Google Scholar
Odani, A., Masuda, H., Inukai, K. & Yamauchi, O. (1992). J. Am. Chem. Soc. 114, 6294–6300. CSD CrossRef CAS Web of Science Google Scholar
Russell, J. R., Garner, C. D. & Joule, J. A. (1992). J. Chem. Soc. Perkin Trans. 1, pp. 1245–1249. CrossRef Web of Science Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Watkin, D. J., Prout, C. K. & Pearce, L. J. (1996). CAMERON. Chemical Crystallography Laboratory, Oxford, England. Google Scholar
Wittle, E. L., O'Dell, B. L., Vandenbelt, J. M. & Pfiffner, J. J. (1947). J. Am. Chem. Soc. 69, 1786–1792. CrossRef CAS PubMed Web of Science Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The primary motivation for pursuing coordination chemistry of pterins is the ubiquitous presence of this heterocyclic system in nature including a substantial number of metalloenzymes (Basu & Burgmayer, 2011; Burgmayer, 1998; Fitzpatrick, 2003; Fukuzumi & Kojima, 2008). Literature survey reveals the existence of only a few X-ray structurally characterized cobalt-pterin/pteridine/lumazine complexes as well as one containing an organocobalt moiety (Acuña-Cueva et al., 2003; Beddoes et al., 1997; Burgmayer & Stiefel, 1988; Funahashi et al., 1997). The concerned ligands usually act as bidentate O,N-donors and none of the above complexes possesses a typical π-acceptor ancillary ligand like 1,10-phenanthroline (phen). In this crystallographic study on the title cobalt(II) complex, possessing both a tridentate pterin ligand and a π-acidic ligand like phen, different aspects are considered, e.g. crystal, molecular and electronic structures.
In the title compound (Fig. 1), the stereochemistry around the CoII atom is essentially distorted octahedral with two N atoms of phen, a pyrazine ring N atom (N3) of the pterin ligand and an aqua O atom forming the equatorial plane; two pterin O atoms (O1 and O3) define the longer axial positions, with the phenolate O3 forming the longest axial bond [2.270 (2) Å]. Extent of distortion of this coordination octahedron is much more pronounced as compared to that of the Co(II)-pteridine complexes reported earlier (Acuña-Cueva et al., 2003; Burgmayer & Stiefel, 1988; Funahashi et al., 1997). A major cause of this departure from regular geometry is that the pterin ligand forms two five-membered chelate rings having small bite angles [75.10 (10) and 76.26 (9)°], instead of only one per pteridine ligand for the earlier cases. Location of the short Co1—N3 bond [2.016 (3) Å] in the equatorial plane is consistent with the literature, which suggests a strong cobalt-pterin interaction (Odani et al., 1992). The pterin ligand is coordinated here as a binegative tridentate ONO donor, as evident from the charge balance of this complex. The phen and pterin rings are nearly perpendicular to each other for minimizing the steric repulsion. The Co1—N1 [2.079 (3) Å] and Co1—N2 [2.123 (3) Å] bond lengths are at par with that of the Co1—N3 bond [2.016 (3) Å] and indicate receipt of π-back donation to both phen and pterin rings from the Co(II) centre (d7) through dπ–pπ interactions. This process is further strengthened by the presence of π-donating phenolate and carboxylate O atoms around the metal centre (Kohzuma et al., 1988).
For rationalizing the near double bond nature of the O3—C18 [1.265 (4) Å] bond, a hypothesis of Joule (Beddoes et al., 1993; Russell et al., 1992) may be invoked, which suggests withdrawl of electron density from the pyrazine ring N6 by the pyrimidine ring C18-carbonyl group through mesomeric interaction. Formation of the O3—Co1 bond accentuates this electron withdrawal towards O3. The electron-rich N7—C17 [1.337 (4) Å] bond may also participate in this electron transfer. The pyrimidine ring is fairly planer and deviations of the C16/N5/C17 and C17/N4/C18 segments with respect to the N7—C17 multiple bonds are 2.6 and 0.7°, respectively.
In the crystal, intermolecular N—H···O, O—H···N and O—H···O hydrogen bonds (Table 1) link the complex molecules and lattice water molecules into a layer parallel to (001) (Fig. 2). The lattice water molecules are decisive for the crystal packing. Fig. 3 reveals π–π stacking interactions involving two parallel, inversion-related pterin rings within the same unit cell and showing face-to-face distance of 3.283 (4) and 3.366 (4) Å. Again the phen rings display two types of π–π stacking on either side of the unit cell. In one case, the adjacent phen rings are essentially parallel to each other with an average interplanar distance of 3.496 (4) Å; on the other side of the unit cell, the face-to-face seperations between parallel phen rings are 3.578 (4) and 3.629 (5) Å.