Tetra­guanidinium bis­[citrato(3−)]cuprate(II) dihydrate

Al-Dajani, M.T.M.; Abdallah, H.H.; Mohamed, N.; Yeap, C.S.; Fun, H.-K.

doi:10.1107/S1600536809046170

metal-organic compounds

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ISSN: 2056-9890

Volume 65| Part 12| December 2009| Pages m1540-m1541

doi:10.1107/S1600536809046170

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Tetraguanidinium bis[citrato(3−)]cuprate(II) dihydrate

Mohammad T. M. Al-Dajani,^a Hassan H. Abdallah,^b Nornisah Mohamed,^a ^* Chin Sing Yeap ^c ‡ and Hoong-Kun Fun ^c ^*§

^aSchool of Pharmaceutical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, ^bSchool of Chemical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia, and ^cX-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
^*Correspondence e-mail: nornisah@usm.my, hkfun@usm.my

(Received 27 October 2009; accepted 3 November 2009; online 7 November 2009)

The asymmetric unit of the title compound, (CH₆N₃)₄[Cu(C₆H₅O₇)₂]·2H₂O, contains one-half of a centrosymmetric Cu^II complex anion, two guanidinium cations and a water molecule. The Cu^II ion, lying on a crystallographic inversion center, is hexacoordinated with two citrate anions in a distorted octahedral geometry. An intramolecular O—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal structure, molecules are linked into a three-dimensional framework by intermolecular N—H⋯O and O—H⋯O hydrogen bonds.

Related literature

For general background to citric acid and guanidine, see: Raczyńska et al. (2003 ); Yamada et al. (2009 ); Sigman et al. (1993 ). For a related structure with a guanidinium cation, see: Al-Dajani et al. (2009 ). For hydrogen-bond motifs, see: Bernstein et al. (1995 ). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ).

Experimental

Crystal data

(CH₆N₃)₄[Cu(C₆H₅O₇)₂]·2H₂O
M_r = 718.12
Triclinic, $[P \overline 1]$
a = 9.0426 (1) Å
b = 9.7763 (2) Å
c = 10.3366 (2) Å
α = 96.503 (1)°
β = 105.441 (1)°
γ = 112.306 (1)°
V = 791.01 (2) Å³
Z = 1
Mo Kα radiation
μ = 0.78 mm⁻¹
T = 296 K
0.60 × 0.39 × 0.32 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.653, T_max = 0.787
37237 measured reflections
7051 independent reflections
6306 reflections with I > 2σ(I)
R_int = 0.024

Refinement

R[F² > 2σ(F²)] = 0.031
wR(F²) = 0.094
S = 1.05
7051 reflections
206 parameters
H-atom parameters constrained
Δρ_max = 0.44 e Å⁻³
Δρ_min = −0.49 e Å⁻³

Table 1
Selected bond lengths (Å)

Cu1—O2	1.9169 (7)
Cu1—O1	2.0857 (8)
Cu1—O3	2.2016 (7)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H1O3⋯O6	0.95	1.61	2.5034 (13)	154
N1—H1N1⋯O5ⁱ	0.86	2.44	3.169 (2)	143
N1—H2N1⋯O2ⁱⁱ	0.86	2.47	3.0810 (19)	129
N1—H2N1⋯O1ⁱⁱⁱ	0.86	2.50	3.3243 (18)	161
N2—H1N2⋯O7^iv	0.86	2.06	2.906 (2)	169
N2—H2N2⋯O4ⁱⁱⁱ	0.86	2.07	2.8811 (14)	157
N3—H1N3⋯O6^iv	0.86	2.02	2.860 (2)	167
N3—H2N3⋯O5ⁱ	0.86	2.12	2.937 (2)	157
N4—H1N4⋯O1W^v	0.86	2.10	2.916 (2)	157
N4—H2N4⋯O6^vi	0.86	2.56	3.0760 (18)	119
N4—H2N4⋯O7ⁱ	0.86	2.26	2.9973 (17)	144
N5—H1N5⋯O2ⁱⁱ	0.86	2.06	2.8484 (15)	152
N5—H2N5⋯O7ⁱ	0.86	2.03	2.8273 (17)	153
N6—H1N6⋯O3ⁱⁱⁱ	0.86	2.18	3.0140 (14)	164
N6—H2N6⋯O4	0.86	1.99	2.8387 (18)	170
O1W—H1W1⋯O4^v	0.78	2.52	3.032 (2)	124
O1W—H2W1⋯O1ⁱⁱ	0.90	2.03	2.932 (2)	175
Symmetry codes: (i) -x+1, -y+1, -z; (ii) x, y-1, z; (iii) -x+1, -y+1, -z+1; (iv) -x, -y+1, -z; (v) -x+2, -y+1, -z+1; (vi) x+1, y, z.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809046170/ci2960sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809046170/ci2960Isup2.hkl

checkCIF report

Comment top

Citric acid or 2-hydroxy-1,2,3-propanetricarboxylic acid contains three carboxyl groups. It is an intermediate in the citric acid cycle in living organisms. It can be added to the food and soft drinks to add a sour or an acidic taste. Guanidine can be formed by the oxidation of guanine as a final product of the protein metabolism. The copper(II) ion in this crystal is coordinated to two citrate ions by the oxygen atoms and the four guanidinium ions neutralize the complex charge (Raczyńska et al., 2003; Yamada et al., 2009; Sigman et al., 1993).

The asymmetric unit of title compound contains half of a Cu^II complex anion, two guanidinium cations and a water solvent molecule, the other half is symmetry generated [symmetry code: -x + 1, -y + 2, -z + 1] (Fig. 1). The Cu^II ion lies on a crystallographic inversion center and is coordinated to six O atoms from two citrate anions to form an octahedral geometry. Four protons are deprotonated from two citric acid molecules to four guanidine molecules resulting in the formation of ions. The geometrical parameters of guanidinium cations agree with those previously reported (Al-Dajani et al., 2009). An intramolecular O3—H1O3···O6 hydrogen bond generates an S(6) ring motif (Bernstein et al., 1995).

In crystal structure (Fig. 2), all guanidinium N–H groups participate in the formation of a three-dimensional framework through N—H···O hydrogen bonds (Table 2). The structure are also stabilized by intermolecular O1W—H1W1···O4 and O1W—H2W1···O1 hydrogen bonds.

Related literature top

For general background to citric acid and guanidine, see: Raczyńska et al. (2003); Yamada et al. (2009); Sigman et al. (1993). For a related guanidinium structure, see: Al-Dajani et al. (2009). For hydrogen-bond motifs, see: Bernstein et al. (1995). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986).

Experimental top

Citric acid (anhydrous) (0.02 mol, 3.85 g) was dissolved in THF in a flat bottom flask with magnetic stirrer. In a separating funnel, guanidine carbonate (0.02 mol, 3.6 g), 99% [H₂NC(NH)NH₂].2H₂CO₃ was dissolved in THF. The guanidine solution was added in small portions to the flask of citric acid with stirring. The reaction mixture was refluxed for 1 h. After cooling the reaction mixture to room temperature, CuCl₂ (0.01 mol, 1.45 g) was added with stirring for 3 h. Blue crystals formed were washed with N,N-dimethylformamide followed by methanol and dried at 353 K.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008; molecular graphics: SHELXTL (Sheldrick, 2008; software used to prepare material for publication: SHELXTL (Sheldrick, 2008 and PLATON (Spek, 2009).

Figures top

	Fig. 1. The molecular structure of the title compound with atom labels and 30% probability ellipsoids for non-H atoms. Molecules/atoms with suffix A are generated by the symmetry operation (1-x, 2-y, 1-z). Intramolecular hydrogen bonds are shown as dashed lines.
	Fig. 2. The crystal packing of title compound, viewed down the a axis, showing hydrogen-bonded (dashed lines) three-dimensional framework.

Tetraguanidinium bis[citrato(3-)]cuprate(II) dihydrate top

Crystal data top

(CH₆N₃)₄[Cu(C₆H₅O₇)₂]·2H₂O	Z = 1
M_r = 718.12	F(000) = 375
Triclinic, P1	D_x = 1.508 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 9.0426 (1) Å	Cell parameters from 9680 reflections
b = 9.7763 (2) Å	θ = 2.3–34.9°
c = 10.3366 (2) Å	µ = 0.78 mm⁻¹
α = 96.503 (1)°	T = 296 K
β = 105.441 (1)°	Block, blue
γ = 112.306 (1)°	0.60 × 0.39 × 0.32 mm
V = 791.01 (2) Å³

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	7051 independent reflections
Radiation source: fine-focus sealed tube	6306 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.024
ϕ and ω scans	θ_max = 35.3°, θ_min = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −14→14
T_min = 0.653, T_max = 0.787	k = −15→15
37237 measured reflections	l = −16→16

Refinement top

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.094	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.0533P)² + 0.108P] where P = (F_o² + 2F_c²)/3
7051 reflections	(Δ/σ)_max < 0.001
206 parameters	Δρ_max = 0.44 e Å⁻³
0 restraints	Δρ_min = −0.49 e Å⁻³

Crystal data top

(CH₆N₃)₄[Cu(C₆H₅O₇)₂]·2H₂O	γ = 112.306 (1)°
M_r = 718.12	V = 791.01 (2) Å³
Triclinic, P1	Z = 1
a = 9.0426 (1) Å	Mo Kα radiation
b = 9.7763 (2) Å	µ = 0.78 mm⁻¹
c = 10.3366 (2) Å	T = 296 K
α = 96.503 (1)°	0.60 × 0.39 × 0.32 mm
β = 105.441 (1)°

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	7051 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	6306 reflections with I > 2σ(I)
T_min = 0.653, T_max = 0.787	R_int = 0.024
37237 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.031	0 restraints
wR(F²) = 0.094	H-atom parameters constrained
S = 1.05	Δρ_max = 0.44 e Å⁻³
7051 reflections	Δρ_min = −0.49 e Å⁻³
206 parameters

Special details top

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

	x	y	z	U_iso*/U_eq
Cu1	0.5000	1.0000	0.5000	0.02544 (5)
O1	0.66219 (12)	0.89568 (10)	0.55711 (9)	0.04046 (18)
O2	0.55673 (11)	1.02356 (8)	0.33541 (8)	0.03511 (15)
O3	0.32813 (9)	0.77094 (8)	0.36675 (7)	0.02790 (12)
H1O3	0.2276	0.7661	0.3035	0.042*
O4	0.76260 (15)	0.72314 (13)	0.55564 (10)	0.0536 (3)
O5	0.57936 (15)	0.90234 (12)	0.15326 (10)	0.0506 (2)
O7	0.09687 (12)	0.65390 (12)	−0.05629 (9)	0.04401 (19)
O6	0.10222 (13)	0.74648 (13)	0.15156 (9)	0.0480 (2)
C1	0.66253 (14)	0.77440 (12)	0.49850 (10)	0.03244 (18)
C2	0.53925 (14)	0.68374 (11)	0.35373 (10)	0.03180 (18)
H2A	0.4699	0.5826	0.3601	0.038*
H2B	0.6052	0.6721	0.2966	0.038*
C3	0.42059 (12)	0.74833 (10)	0.27880 (9)	0.02586 (14)
C4	0.52711 (13)	0.90199 (11)	0.25150 (10)	0.02936 (16)
C5	0.29501 (13)	0.63732 (12)	0.14090 (10)	0.03315 (18)
H5A	0.3568	0.6313	0.0784	0.040*
H5B	0.2432	0.5367	0.1567	0.040*
C6	0.15557 (13)	0.68329 (13)	0.07232 (11)	0.03335 (18)
N1	0.33925 (19)	0.13097 (19)	0.12541 (16)	0.0627 (4)
H1N1	0.3944	0.1103	0.0759	0.075*
H2N1	0.3625	0.1237	0.2099	0.075*
N2	0.13528 (17)	0.20918 (16)	0.14703 (11)	0.0503 (3)
H1N2	0.0587	0.2390	0.1118	0.060*
H2N2	0.1577	0.2022	0.2316	0.060*
N3	0.18333 (18)	0.18500 (18)	−0.05808 (13)	0.0548 (3)
H1N3	0.1067	0.2149	−0.0929	0.066*
H2N3	0.2372	0.1622	−0.1078	0.066*
C7	0.21821 (16)	0.17412 (15)	0.07130 (13)	0.0409 (2)
N4	0.86185 (16)	0.53693 (13)	0.28012 (13)	0.0475 (2)
H1N4	0.8743	0.6260	0.3163	0.057*
H2N4	0.8867	0.5223	0.2066	0.057*
N5	0.78586 (17)	0.28597 (12)	0.28065 (14)	0.0506 (3)
H1N5	0.7486	0.2106	0.3171	0.061*
H2N5	0.8111	0.2727	0.2071	0.061*
N6	0.76591 (17)	0.44356 (13)	0.45058 (12)	0.0469 (2)
H1N6	0.7286	0.3687	0.4875	0.056*
H2N6	0.7782	0.5324	0.4872	0.056*
C8	0.80435 (14)	0.42221 (12)	0.33777 (12)	0.03575 (19)
O1W	0.9973 (2)	0.13741 (17)	0.59833 (19)	0.0955 (6)
H1W1	0.9976	0.1225	0.5223	0.143*
H2W1	0.8945	0.0656	0.5902	0.143*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.03201 (8)	0.02210 (7)	0.02568 (7)	0.01325 (6)	0.01258 (6)	0.00553 (5)
O1	0.0452 (4)	0.0371 (4)	0.0360 (4)	0.0230 (3)	0.0056 (3)	−0.0025 (3)
O2	0.0494 (4)	0.0258 (3)	0.0361 (3)	0.0148 (3)	0.0244 (3)	0.0102 (3)
O3	0.0326 (3)	0.0312 (3)	0.0270 (3)	0.0169 (3)	0.0150 (2)	0.0095 (2)
O4	0.0671 (6)	0.0638 (6)	0.0356 (4)	0.0484 (5)	0.0001 (4)	0.0013 (4)
O5	0.0680 (6)	0.0506 (5)	0.0475 (5)	0.0245 (5)	0.0415 (5)	0.0142 (4)
O7	0.0438 (4)	0.0615 (5)	0.0297 (3)	0.0260 (4)	0.0114 (3)	0.0117 (3)
O6	0.0495 (5)	0.0745 (6)	0.0368 (4)	0.0434 (5)	0.0156 (4)	0.0118 (4)
C1	0.0374 (5)	0.0347 (4)	0.0283 (4)	0.0200 (4)	0.0097 (3)	0.0055 (3)
C2	0.0381 (5)	0.0299 (4)	0.0298 (4)	0.0209 (4)	0.0075 (3)	0.0030 (3)
C3	0.0307 (4)	0.0259 (3)	0.0257 (3)	0.0156 (3)	0.0118 (3)	0.0055 (3)
C4	0.0349 (4)	0.0310 (4)	0.0297 (4)	0.0173 (3)	0.0166 (3)	0.0097 (3)
C5	0.0345 (4)	0.0344 (4)	0.0302 (4)	0.0184 (4)	0.0081 (3)	0.0007 (3)
C6	0.0317 (4)	0.0402 (5)	0.0306 (4)	0.0168 (4)	0.0118 (3)	0.0095 (4)
N1	0.0661 (8)	0.0851 (10)	0.0603 (7)	0.0545 (8)	0.0185 (6)	0.0314 (7)
N2	0.0583 (7)	0.0732 (8)	0.0362 (5)	0.0412 (6)	0.0187 (5)	0.0210 (5)
N3	0.0626 (7)	0.0884 (9)	0.0431 (5)	0.0535 (7)	0.0265 (5)	0.0286 (6)
C7	0.0425 (6)	0.0463 (6)	0.0403 (5)	0.0248 (5)	0.0127 (4)	0.0160 (4)
N4	0.0615 (7)	0.0363 (5)	0.0504 (6)	0.0167 (5)	0.0300 (5)	0.0196 (4)
N5	0.0674 (7)	0.0337 (4)	0.0606 (7)	0.0170 (5)	0.0423 (6)	0.0136 (4)
N6	0.0701 (7)	0.0422 (5)	0.0486 (6)	0.0307 (5)	0.0365 (5)	0.0214 (4)
C8	0.0382 (5)	0.0329 (4)	0.0413 (5)	0.0146 (4)	0.0197 (4)	0.0144 (4)
O1W	0.0812 (9)	0.0655 (8)	0.1106 (12)	−0.0041 (7)	0.0578 (9)	−0.0212 (8)

Geometric parameters (Å, º) top

Cu1—O2ⁱ	1.9169 (7)	C5—H5B	0.97
Cu1—O2	1.9169 (7)	N1—C7	1.3292 (16)
Cu1—O1	2.0857 (8)	N1—H1N1	0.86
Cu1—O1ⁱ	2.0857 (8)	N1—H2N1	0.86
Cu1—O3ⁱ	2.2015 (7)	N2—C7	1.3189 (17)
Cu1—O3	2.2016 (7)	N2—H1N2	0.86
O1—C1	1.2704 (12)	N2—H2N2	0.86
O2—C4	1.2798 (12)	N3—C7	1.3162 (16)
O3—C3	1.4401 (11)	N3—H1N3	0.86
O3—H1O3	0.95	N3—H2N3	0.86
O4—C1	1.2432 (13)	N4—C8	1.3255 (14)
O5—C4	1.2286 (12)	N4—H1N4	0.86
O7—C6	1.2464 (13)	N4—H2N4	0.86
O6—C6	1.2678 (13)	N5—C8	1.3232 (15)
C1—C2	1.5261 (14)	N5—H1N5	0.86
C2—C3	1.5273 (13)	N5—H2N5	0.86
C2—H2A	0.97	N6—C8	1.3191 (15)
C2—H2B	0.97	N6—H1N6	0.86
C3—C5	1.5334 (13)	N6—H2N6	0.86
C3—C4	1.5513 (13)	O1W—H1W1	0.78
C5—C6	1.5234 (14)	O1W—H2W1	0.90
C5—H5A	0.97

O2ⁱ—Cu1—O2	179.999 (1)	O5—C4—C3	119.72 (9)
O2ⁱ—Cu1—O1	89.36 (4)	O2—C4—C3	116.95 (8)
O2—Cu1—O1	90.64 (4)	C6—C5—C3	113.23 (8)
O2ⁱ—Cu1—O1ⁱ	90.64 (4)	C6—C5—H5A	108.9
O2—Cu1—O1ⁱ	89.36 (4)	C3—C5—H5A	108.9
O1—Cu1—O1ⁱ	180.00 (3)	C6—C5—H5B	108.9
O2ⁱ—Cu1—O3ⁱ	80.58 (3)	C3—C5—H5B	108.9
O2—Cu1—O3ⁱ	99.42 (3)	H5A—C5—H5B	107.7
O1—Cu1—O3ⁱ	97.62 (3)	O7—C6—O6	123.57 (10)
O1ⁱ—Cu1—O3ⁱ	82.38 (3)	O7—C6—C5	119.46 (10)
O2ⁱ—Cu1—O3	99.42 (3)	O6—C6—C5	116.94 (9)
O2—Cu1—O3	80.58 (3)	C7—N1—H1N1	120.0
O1—Cu1—O3	82.38 (3)	C7—N1—H2N1	120.0
O1ⁱ—Cu1—O3	97.62 (3)	H1N1—N1—H2N1	120.0
O3ⁱ—Cu1—O3	180.0	C7—N2—H1N2	120.0
C1—O1—Cu1	131.70 (7)	C7—N2—H2N2	120.0
C4—O2—Cu1	116.90 (6)	H1N2—N2—H2N2	120.0
C3—O3—Cu1	102.63 (5)	C7—N3—H1N3	120.0
C3—O3—H1O3	103.2	C7—N3—H2N3	120.0
Cu1—O3—H1O3	113.8	H1N3—N3—H2N3	120.0
O4—C1—O1	122.02 (10)	N3—C7—N2	119.75 (11)
O4—C1—C2	116.47 (9)	N3—C7—N1	119.69 (13)
O1—C1—C2	121.51 (9)	N2—C7—N1	120.54 (12)
C1—C2—C3	117.43 (7)	C8—N4—H1N4	120.0
C1—C2—H2A	107.9	C8—N4—H2N4	120.0
C3—C2—H2A	107.9	H1N4—N4—H2N4	120.0
C1—C2—H2B	107.9	C8—N5—H1N5	120.0
C3—C2—H2B	107.9	C8—N5—H2N5	120.0
H2A—C2—H2B	107.2	H1N5—N5—H2N5	120.0
O3—C3—C2	107.59 (7)	C8—N6—H1N6	120.0
O3—C3—C5	109.31 (8)	C8—N6—H2N6	120.0
C2—C3—C5	110.83 (7)	H1N6—N6—H2N6	120.0
O3—C3—C4	110.36 (7)	N6—C8—N5	120.42 (10)
C2—C3—C4	109.34 (8)	N6—C8—N4	120.42 (11)
C5—C3—C4	109.39 (8)	N5—C8—N4	119.15 (11)
O5—C4—O2	123.33 (10)	H1W1—O1W—H2W1	101.6

O2ⁱ—Cu1—O1—C1	118.93 (11)	Cu1—O3—C3—C4	−32.73 (8)
O2—Cu1—O1—C1	−61.07 (11)	C1—C2—C3—O3	−55.52 (11)
O3ⁱ—Cu1—O1—C1	−160.66 (11)	C1—C2—C3—C5	−174.99 (9)
O3—Cu1—O1—C1	19.33 (11)	C1—C2—C3—C4	64.35 (11)
O1—Cu1—O2—C4	58.64 (8)	Cu1—O2—C4—O5	−169.11 (10)
O1ⁱ—Cu1—O2—C4	−121.36 (8)	Cu1—O2—C4—C3	10.43 (12)
O3ⁱ—Cu1—O2—C4	156.47 (8)	O3—C3—C4—O5	−161.50 (10)
O3—Cu1—O2—C4	−23.53 (8)	C2—C3—C4—O5	80.34 (12)
O2ⁱ—Cu1—O3—C3	−149.08 (5)	C5—C3—C4—O5	−41.19 (13)
O2—Cu1—O3—C3	30.92 (5)	O3—C3—C4—O2	18.95 (12)
O1—Cu1—O3—C3	−61.01 (5)	C2—C3—C4—O2	−99.21 (10)
O1ⁱ—Cu1—O3—C3	118.99 (5)	C5—C3—C4—O2	139.26 (9)
Cu1—O1—C1—O4	−173.35 (10)	O3—C3—C5—C6	52.33 (11)
Cu1—O1—C1—C2	6.55 (17)	C2—C3—C5—C6	170.76 (9)
O4—C1—C2—C3	−177.27 (11)	C4—C3—C5—C6	−68.62 (10)
O1—C1—C2—C3	2.83 (16)	C3—C5—C6—O7	147.04 (11)
Cu1—O3—C3—C2	86.49 (7)	C3—C5—C6—O6	−34.97 (14)
Cu1—O3—C3—C5	−153.08 (6)

Symmetry code: (i) −x+1, −y+2, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H1O3···O6	0.95	1.61	2.5034 (13)	154
N1—H1N1···O5ⁱⁱ	0.86	2.44	3.169 (2)	143
N1—H2N1···O2ⁱⁱⁱ	0.86	2.47	3.0810 (19)	129
N1—H2N1···O1^iv	0.86	2.50	3.3243 (18)	161
N2—H1N2···O7^v	0.86	2.06	2.906 (2)	169
N2—H2N2···O4^iv	0.86	2.07	2.8811 (14)	157
N3—H1N3···O6^v	0.86	2.02	2.860 (2)	167
N3—H2N3···O5ⁱⁱ	0.86	2.12	2.937 (2)	157
N4—H1N4···O1W^vi	0.86	2.10	2.916 (2)	157
N4—H2N4···O6^vii	0.86	2.56	3.0760 (18)	119
N4—H2N4···O7ⁱⁱ	0.86	2.26	2.9973 (17)	144
N5—H1N5···O2ⁱⁱⁱ	0.86	2.06	2.8484 (15)	152
N5—H2N5···O7ⁱⁱ	0.86	2.03	2.8273 (17)	153
N6—H1N6···O3^iv	0.86	2.18	3.0140 (14)	164
N6—H2N6···O4	0.86	1.99	2.8387 (18)	170
O1W—H1W1···O4^vi	0.78	2.52	3.032 (2)	124
O1W—H2W1···O1ⁱⁱⁱ	0.90	2.03	2.932 (2)	175

Symmetry codes: (ii) −x+1, −y+1, −z; (iii) x, y−1, z; (iv) −x+1, −y+1, −z+1; (v) −x, −y+1, −z; (vi) −x+2, −y+1, −z+1; (vii) x+1, y, z.

Experimental details

Crystal data
Chemical formula	(CH₆N₃)₄[Cu(C₆H₅O₇)₂]·2H₂O
M_r	718.12
Crystal system, space group	Triclinic, P1
Temperature (K)	296
a, b, c (Å)	9.0426 (1), 9.7763 (2), 10.3366 (2)
α, β, γ (°)	96.503 (1), 105.441 (1), 112.306 (1)
V (Å³)	791.01 (2)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	0.78
Crystal size (mm)	0.60 × 0.39 × 0.32

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2005)
T_min, T_max	0.653, 0.787
No. of measured, independent and observed [I > 2σ(I)] reflections	37237, 7051, 6306
R_int	0.024
(sin θ/λ)_max (Å⁻¹)	0.812

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.031, 0.094, 1.05
No. of reflections	7051
No. of parameters	206
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.44, −0.49

Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXTL (Sheldrick, 2008), SHELXTL (Sheldrick, 2008 and PLATON (Spek, 2009).

Selected bond lengths (Å) top

Cu1—O2	1.9169 (7)	Cu1—O3	2.2016 (7)
Cu1—O1	2.0857 (8)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O3—H1O3···O6	0.95	1.61	2.5034 (13)	154
N1—H1N1···O5ⁱ	0.86	2.44	3.169 (2)	143
N1—H2N1···O2ⁱⁱ	0.86	2.47	3.0810 (19)	129
N1—H2N1···O1ⁱⁱⁱ	0.86	2.50	3.3243 (18)	161
N2—H1N2···O7^iv	0.86	2.06	2.906 (2)	169
N2—H2N2···O4ⁱⁱⁱ	0.86	2.07	2.8811 (14)	157
N3—H1N3···O6^iv	0.86	2.02	2.860 (2)	167
N3—H2N3···O5ⁱ	0.86	2.12	2.937 (2)	157
N4—H1N4···O1W^v	0.86	2.10	2.916 (2)	157
N4—H2N4···O6^vi	0.86	2.56	3.0760 (18)	119
N4—H2N4···O7ⁱ	0.86	2.26	2.9973 (17)	144
N5—H1N5···O2ⁱⁱ	0.86	2.06	2.8484 (15)	152
N5—H2N5···O7ⁱ	0.86	2.03	2.8273 (17)	153
N6—H1N6···O3ⁱⁱⁱ	0.86	2.18	3.0140 (14)	164
N6—H2N6···O4	0.86	1.99	2.8387 (18)	170
O1W—H1W1···O4^v	0.78	2.52	3.032 (2)	124
O1W—H2W1···O1ⁱⁱ	0.90	2.03	2.932 (2)	175

Symmetry codes: (i) −x+1, −y+1, −z; (ii) x, y−1, z; (iii) −x+1, −y+1, −z+1; (iv) −x, −y+1, −z; (v) −x+2, −y+1, −z+1; (vi) x+1, y, z.

Footnotes

‡Thomson Reuters ResearcherID: A-5523-2009.

§Thomson Reuters ResearcherID: A-3561-2009.

Acknowledgements

NM gratefully acknowledges funding from Universiti Sains Malaysia (USM) under the University Research Grant (No. 1001/PFARMASI/815025). HKF thanks USM for the Research University Golden Goose Grant (No. 1001/PFIZIK/811012). CSY thanks USM for the award of a USM Fellowship.

References

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