supplementary materials


hy2609 scheme

Acta Cryst. (2013). E69, m70-m71    [ doi:10.1107/S1600536812051185 ]

(2-Amino-7-methyl-4-oxidopteridine-6-carboxylato-[kappa]3O4,N5,O6)aqua(1,10-phenanthroline-[kappa]2N,N')cobalt(II) trihydrate

S. S. Baisya, S. Sen and P. S. Roy

Abstract top

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). [pi]-[pi] 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].

Comment top

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 ππ 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 ππ 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.

Related literature top

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).

Experimental top

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%).

Refinement top

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.

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: 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).

Figures top
[Figure 1] 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.
[Figure 2] 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).
[Figure 3] Fig. 3. A molecular packing diagram highlighting ππ stacking interactions between two neighbouring phen–phen and pterin–pterin rings, respectively.
(2-Amino-7-methyl-4-oxidopteridine-6-carboxylato- κ3O4,N5,O6)aqua(1,10-phenanthroline- κ2N,N')cobalt(II) trihydrate top
Crystal data top
[Co(C8H5N5O3)(C12H8N2)(H2O)]·3H2OZ = 2
Mr = 530.36F(000) = 546
Triclinic, P1Dx = 1.659 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 8.454 (2) ÅCell parameters from 8945 reflections
b = 9.934 (3) Åθ = 2–28°
c = 13.778 (4) ŵ = 0.87 mm1
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
Data collection top
Bruker Kappa APEXII CCD
diffractometer
4360 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.030
φ and ω scansθmax = 28.2°, θmin = 1.5°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 1111
Tmin = 0.82, Tmax = 0.97k = 1213
8945 measured reflectionsl = 1818
4726 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.057H-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 reflectionsΔρmax = 0.99 e Å3
316 parametersΔρmin = 0.88 e Å3
0 restraints
Crystal data top
[Co(C8H5N5O3)(C12H8N2)(H2O)]·3H2Oγ = 110.603 (4)°
Mr = 530.36V = 1061.8 (5) Å3
Triclinic, P1Z = 2
a = 8.454 (2) ÅMo Kα radiation
b = 9.934 (3) ŵ = 0.87 mm1
c = 13.778 (4) ÅT = 110 K
α = 97.534 (4)°0.23 × 0.11 × 0.04 mm
β = 95.281 (4)°
Data collection top
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 = 0.97Rint = 0.030
8945 measured reflectionsθmax = 28.2°
Refinement top
R[F2 > 2σ(F2)] = 0.057H-atom parameters constrained
wR(F2) = 0.129Δρmax = 0.99 e Å3
S = 1.03Δρmin = 0.88 e Å3
4726 reflectionsAbsolute structure: ?
316 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Co10.45982 (5)0.22172 (4)0.22887 (3)0.0125
O10.2062 (3)0.0747 (2)0.23341 (17)0.0176
C130.1224 (4)0.1182 (3)0.2948 (2)0.0159
O20.0205 (3)0.0408 (2)0.31159 (18)0.0204
C140.2096 (4)0.2762 (3)0.3463 (2)0.0150
N30.3618 (3)0.3367 (3)0.32052 (19)0.0137
C190.4572 (4)0.4746 (3)0.3559 (2)0.0137
C160.4012 (4)0.5628 (3)0.4205 (2)0.0151
N50.4986 (3)0.7057 (3)0.4529 (2)0.0154
C170.6493 (4)0.7539 (3)0.4170 (2)0.0157
N40.7169 (3)0.6739 (3)0.3559 (2)0.0161
C180.6243 (4)0.5321 (3)0.3254 (2)0.0148
O30.6704 (3)0.4463 (2)0.26886 (17)0.0174
N70.7460 (4)0.8957 (3)0.4440 (2)0.0199
H1410.82930.93430.41350.0223*
H1420.70860.95220.47750.0228*
N60.2466 (3)0.5028 (3)0.4504 (2)0.0176
C150.1508 (4)0.3621 (3)0.4146 (2)0.0171
C200.0163 (4)0.2992 (4)0.4506 (3)0.0256
H1720.03590.36960.49630.0378*
H1730.01850.21880.48290.0383*
H1710.10610.26800.39850.0380*
O40.5538 (3)0.1469 (2)0.35063 (17)0.0185
H1810.49640.06630.35970.0272*
H1820.54180.18940.40130.0271*
N20.3758 (3)0.2801 (3)0.0963 (2)0.0162
C120.2567 (4)0.3370 (4)0.0798 (3)0.0196
C110.2191 (4)0.3750 (4)0.0116 (3)0.0230
C100.3071 (4)0.3548 (4)0.0867 (3)0.0220
C80.4354 (4)0.2958 (4)0.0719 (2)0.0183
C90.4634 (4)0.2593 (3)0.0218 (2)0.0138
C50.5897 (4)0.1963 (3)0.0422 (2)0.0147
N10.6075 (3)0.1592 (3)0.1330 (2)0.0152
C10.7247 (4)0.1018 (3)0.1537 (2)0.0178
C20.8260 (4)0.0749 (4)0.0839 (3)0.0225
C30.8069 (4)0.1096 (4)0.0079 (3)0.0221
C40.6854 (4)0.1721 (3)0.0323 (2)0.0179
C60.6545 (4)0.2115 (4)0.1271 (3)0.0227
C70.5346 (5)0.2690 (4)0.1461 (3)0.0241
H3210.51240.28980.20830.0280*
H3110.71360.19260.17710.0268*
H2910.87040.08980.05540.0258*
H2810.90860.03770.10200.0257*
H2710.74010.08140.21710.0208*
H2210.28150.37790.14770.0263*
H2110.13460.41150.02110.0270*
H2010.19760.35310.13040.0229*
O70.9931 (4)0.4695 (3)0.1919 (3)0.0445
H3311.03550.55680.19930.0644*
H3320.93090.48190.23050.0648*
O50.0341 (3)0.2327 (3)0.28207 (18)0.0224
H3410.04180.15590.26370.0322*
H3420.04720.25710.31240.0321*
O60.3374 (3)0.0951 (2)0.40693 (18)0.0204
H3510.24680.14200.36960.0287*
H3520.37950.15520.41820.0294*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Co10.0135 (2)0.0131 (2)0.0129 (2)0.00622 (16)0.00458 (15)0.00324 (15)
O10.0164 (11)0.0142 (11)0.0210 (12)0.0040 (9)0.0048 (9)0.0026 (9)
C130.0156 (15)0.0157 (15)0.0168 (15)0.0064 (12)0.0002 (12)0.0050 (12)
O20.0143 (11)0.0173 (11)0.0269 (13)0.0015 (9)0.0059 (9)0.0056 (10)
C140.0134 (14)0.0150 (15)0.0185 (15)0.0062 (12)0.0048 (12)0.0053 (12)
N30.0134 (12)0.0130 (12)0.0153 (13)0.0049 (10)0.0035 (10)0.0038 (10)
C190.0139 (14)0.0141 (14)0.0156 (15)0.0062 (12)0.0053 (12)0.0057 (12)
C160.0158 (15)0.0172 (15)0.0152 (15)0.0085 (12)0.0029 (12)0.0050 (12)
N50.0149 (13)0.0129 (12)0.0196 (14)0.0060 (10)0.0040 (10)0.0030 (10)
C170.0157 (15)0.0175 (15)0.0167 (15)0.0083 (12)0.0030 (12)0.0063 (12)
N40.0150 (13)0.0148 (13)0.0202 (14)0.0057 (10)0.0078 (11)0.0047 (11)
C180.0144 (15)0.0169 (15)0.0150 (15)0.0065 (12)0.0036 (12)0.0063 (12)
O30.0173 (11)0.0170 (11)0.0193 (12)0.0073 (9)0.0065 (9)0.0028 (9)
N70.0188 (14)0.0136 (13)0.0264 (15)0.0044 (11)0.0081 (12)0.0020 (11)
N60.0164 (13)0.0169 (13)0.0224 (14)0.0083 (11)0.0071 (11)0.0041 (11)
C150.0148 (15)0.0171 (15)0.0226 (16)0.0075 (12)0.0065 (12)0.0079 (13)
C200.0163 (16)0.0207 (17)0.040 (2)0.0056 (14)0.0126 (15)0.0024 (15)
O40.0198 (12)0.0193 (11)0.0174 (11)0.0069 (9)0.0052 (9)0.0063 (9)
N20.0151 (13)0.0150 (13)0.0203 (14)0.0061 (10)0.0063 (11)0.0055 (11)
C120.0169 (16)0.0171 (15)0.0263 (18)0.0064 (13)0.0075 (13)0.0055 (13)
C110.0193 (17)0.0195 (16)0.0319 (19)0.0082 (14)0.0003 (14)0.0098 (14)
C100.0202 (17)0.0232 (17)0.0224 (17)0.0061 (14)0.0007 (13)0.0107 (14)
C80.0177 (16)0.0168 (15)0.0178 (16)0.0030 (12)0.0007 (12)0.0044 (13)
C90.0133 (14)0.0114 (14)0.0153 (15)0.0026 (11)0.0032 (11)0.0022 (11)
C50.0129 (14)0.0113 (14)0.0176 (15)0.0020 (11)0.0022 (12)0.0015 (12)
N10.0152 (13)0.0133 (12)0.0158 (13)0.0040 (10)0.0034 (10)0.0013 (10)
C10.0171 (15)0.0150 (15)0.0199 (16)0.0058 (12)0.0002 (12)0.0005 (12)
C20.0169 (16)0.0214 (17)0.0312 (19)0.0103 (14)0.0035 (14)0.0025 (14)
C30.0162 (16)0.0190 (16)0.0298 (19)0.0059 (13)0.0079 (14)0.0016 (14)
C40.0152 (15)0.0162 (15)0.0200 (16)0.0032 (12)0.0055 (13)0.0009 (13)
C60.0241 (17)0.0251 (17)0.0181 (17)0.0072 (14)0.0093 (14)0.0026 (14)
C70.0299 (19)0.0254 (18)0.0169 (16)0.0070 (15)0.0085 (14)0.0086 (14)
O70.0352 (16)0.0272 (15)0.074 (2)0.0127 (13)0.0292 (16)0.0010 (15)
O50.0178 (11)0.0184 (12)0.0318 (14)0.0057 (9)0.0095 (10)0.0059 (10)
O60.0192 (12)0.0166 (11)0.0266 (13)0.0077 (9)0.0020 (10)0.0060 (10)
Geometric parameters (Å, º) top
Co1—O12.140 (2)N2—C121.333 (4)
Co1—N32.016 (3)N2—C91.355 (4)
Co1—O32.270 (2)C12—C111.402 (5)
Co1—O42.120 (2)C12—H2010.923
Co1—N22.123 (3)C11—C101.363 (5)
Co1—N12.079 (3)C11—H2110.914
O1—C131.279 (4)C10—C81.414 (5)
C13—O21.244 (4)C10—H2210.926
C13—C141.519 (4)C8—C91.408 (4)
C14—N31.319 (4)C8—C71.435 (5)
C14—C151.426 (4)C9—C51.439 (4)
N3—C191.319 (4)C5—N11.359 (4)
C19—C161.397 (4)C5—C41.411 (4)
C19—C181.450 (4)N1—C11.333 (4)
C16—N51.354 (4)C1—C21.406 (5)
C16—N61.360 (4)C1—H2710.930
N5—C171.360 (4)C2—C31.363 (5)
C17—N41.378 (4)C2—H2810.928
C17—N71.337 (4)C3—C41.412 (5)
N4—C181.335 (4)C3—H2910.928
C18—O31.265 (4)C4—C61.439 (5)
N7—H1410.852C6—C71.349 (5)
N7—H1420.843C6—H3110.925
N6—C151.342 (4)C7—H3210.926
C15—C201.491 (4)O7—H3310.800
C20—H1720.947O7—H3320.810
C20—H1730.960O5—H3410.811
C20—H1710.930O5—H3420.820
O4—H1810.810O6—H3510.830
O4—H1820.801O6—H3520.820
O1—Co1—N375.10 (10)H172—C20—H171106.6
O1—Co1—O3151.22 (8)H173—C20—H171109.7
N3—Co1—O376.26 (9)Co1—O4—H181116.6
O1—Co1—O490.13 (9)Co1—O4—H182109.7
N3—Co1—O490.23 (10)H181—O4—H18295.0
O3—Co1—O492.74 (9)Co1—N2—C12128.8 (2)
O1—Co1—N290.99 (10)Co1—N2—C9112.7 (2)
N3—Co1—N296.45 (10)C12—N2—C9118.5 (3)
O3—Co1—N289.46 (9)N2—C12—C11122.3 (3)
O4—Co1—N2173.29 (10)N2—C12—H201119.1
O1—Co1—N1119.55 (10)C11—C12—H201118.6
N3—Co1—N1164.48 (10)C12—C11—C10119.6 (3)
O3—Co1—N188.76 (9)C12—C11—H211120.2
O4—Co1—N194.58 (10)C10—C11—H211120.2
N2—Co1—N179.12 (10)C11—C10—C8119.9 (3)
Co1—O1—C13116.8 (2)C11—C10—H221120.1
O1—C13—O2124.1 (3)C8—C10—H221120.0
O1—C13—C14114.6 (3)C10—C8—C9116.7 (3)
O2—C13—C14121.2 (3)C10—C8—C7124.4 (3)
C13—C14—N3111.4 (3)C9—C8—C7118.9 (3)
C13—C14—C15129.9 (3)C8—C9—N2123.1 (3)
N3—C14—C15118.8 (3)C8—C9—C5120.1 (3)
Co1—N3—C14121.6 (2)N2—C9—C5116.8 (3)
Co1—N3—C19117.6 (2)C9—C5—N1117.5 (3)
C14—N3—C19120.8 (3)C9—C5—C4119.5 (3)
N3—C19—C16121.8 (3)N1—C5—C4123.0 (3)
N3—C19—C18117.4 (3)Co1—N1—C5113.6 (2)
C16—C19—C18120.7 (3)Co1—N1—C1127.6 (2)
C19—C16—N5120.8 (3)C5—N1—C1118.5 (3)
C19—C16—N6118.7 (3)N1—C1—C2122.0 (3)
N5—C16—N6120.4 (3)N1—C1—H271118.0
C16—N5—C17115.1 (3)C2—C1—H271120.0
N5—C17—N4127.9 (3)C1—C2—C3119.8 (3)
N5—C17—N7117.0 (3)C1—C2—H281119.3
N4—C17—N7115.1 (3)C3—C2—H281120.9
C17—N4—C18117.6 (3)C2—C3—C4119.9 (3)
C19—C18—N4117.7 (3)C2—C3—H291120.7
C19—C18—O3118.1 (3)C4—C3—H291119.4
N4—C18—O3124.2 (3)C3—C4—C5116.8 (3)
Co1—O3—C18110.63 (19)C3—C4—C6124.2 (3)
C17—N7—H141119.8C5—C4—C6119.0 (3)
C17—N7—H142119.9C4—C6—C7121.2 (3)
H141—N7—H142117.6C4—C6—H311119.5
C16—N6—C15119.0 (3)C7—C6—H311119.2
C14—C15—N6120.8 (3)C8—C7—C6121.3 (3)
C14—C15—C20121.7 (3)C8—C7—H321118.4
N6—C15—C20117.4 (3)C6—C7—H321120.3
C15—C20—H172111.5H331—O7—H33286.2
C15—C20—H173110.1H341—O5—H342108.7
H172—C20—H173108.2H351—O6—H352105.5
C15—C20—H171110.7
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N7—H141···O2i0.852.122.942 (4)163
N7—H142···O6ii0.842.152.970 (4)165
O4—H181···O60.811.932.717 (3)164
O4—H182···N5ii0.802.253.051 (4)176
O5—H341···O10.822.343.079 (4)151
O5—H341···O20.822.232.896 (4)139
O5—H342···N4iii0.822.042.844 (4)166
O6—H351···O50.831.922.740 (4)174
O6—H352···N5iv0.822.052.871 (4)176
O7—H331···O5i0.802.252.941 (4)145
O7—H332···O30.812.232.962 (5)151
Symmetry codes: (i) x+1, y+1, z; (ii) x+1, y+1, z+1; (iii) x1, y1, z; (iv) x, y1, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N7—H141···O2i0.852.122.942 (4)163
N7—H142···O6ii0.842.152.970 (4)165
O4—H181···O60.811.932.717 (3)164
O4—H182···N5ii0.802.253.051 (4)176
O5—H341···O10.822.343.079 (4)151
O5—H341···O20.822.232.896 (4)139
O5—H342···N4iii0.822.042.844 (4)166
O6—H351···O50.831.922.740 (4)174
O6—H352···N5iv0.822.052.871 (4)176
O7—H331···O5i0.802.252.941 (4)145
O7—H332···O30.812.232.962 (5)151
Symmetry codes: (i) x+1, y+1, z; (ii) x+1, y+1, z+1; (iii) x1, y1, z; (iv) x, y1, z.
Acknowledgements top

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 infrastructural support.

references
References top

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.

Basu, P. & Burgmayer, S. J. N. (2011). Coord. Chem. Rev. 255, 1016–1038.

Beddoes, R. L., Dinsmore, A., Helliwell, M., Garner, C. D. & Joule, J. A. (1997). Acta Cryst. C53, 213–215.

Beddoes, R. L., Russell, J. R., Garner, C. D. & Joule, J. A. (1993). Acta Cryst. C49, 1649–1652.

Betteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487.

Bruker (2007). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Burgmayer, S. J. N. (1998). Struct. Bond. 92, 67–119.

Burgmayer, S. J. N. & Stiefel, E. I. (1988). Inorg. Chem. 27, 4059–4061.

Fitzpatrick, P. F. (2003). Biochemistry, 42, 14083–14091.

Fukuzumi, S. & Kojima, T. (2008). J. Biol. Inorg. Chem. 13, 321–333.

Funahashi, Y., Hara, Y., Masuda, H. & Yamauchi, O. (1997). Inorg. Chem. 36, 3869–3875.

Kohzuma, T., Odani, A., Morita, Y., Takani, M. & Yamauchi, O. (1988). Inorg. Chem. 27, 3854–3858.

Odani, A., Masuda, H., Inukai, K. & Yamauchi, O. (1992). J. Am. Chem. Soc. 114, 6294–6300.

Russell, J. R., Garner, C. D. & Joule, J. A. (1992). J. Chem. Soc. Perkin Trans. 1, pp. 1245–1249.

Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Watkin, D. J., Prout, C. K. & Pearce, L. J. (1996). CAMERON. Chemical Crystallography Laboratory, Oxford, England.

Wittle, E. L., O'Dell, B. L., Vandenbelt, J. M. & Pfiffner, J. J. (1947). J. Am. Chem. Soc. 69, 1786–1792.