Bis(biguanido-κ²N,N′)nickel(II) dihydrate

In the title compound, [Ni(C₂H₆N₅)₂]·2H₂O, the Ni cation (site symmetry ) is coordinated by four N atoms from two bidenate ligands in a square-planar arrangement. A network of O—H...N, N—H...N and N—H...O hydrogen bonds helps to consolidate the crystal packing.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](N-C) = 0.004 Å
• R factor = 0.036
• wR factor = 0.086
• Data-to-parameter ratio = 14.6

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT417_ALERT_2_C Short Inter D-H..H-D       H2W    ..  H5A     ..       2.14 Ang.
PLAT420_ALERT_2_C D-H Without Acceptor       N1     -   H1     ...          ?
PLAT420_ALERT_2_C D-H Without Acceptor       N4     -   H4     ...          ?

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL/PC (Sheldrick, 1999); software used to prepare material for publication: SHELXTL/PC.

Bis(biguanido-κ²N,N')nickel(II) dihydrate

Crystal data

[Ni(C2H6N5)2]·2H2O	F(000) = 616
Mr = 294.98	Dx = 1.776 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 1226 reflections
a = 6.964 (5) Å	θ = 4.2–25.2°
b = 7.139 (5) Å	µ = 1.77 mm^−1
c = 22.193 (15) Å	T = 298 K
V = 1103.3 (13) Å^3	Plate, yellow
Z = 4	0.20 × 0.20 × 0.02 mm

Data collection

Bruker SMART 1K CCD area-detector diffractometer	1154 independent reflections
Radiation source: fine-focus sealed tube	761 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.064
φ and ω scans	θmax = 26.9°, θmin = 1.8°
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)	h = −8→7
Tmin = 0.718, Tmax = 0.965	k = −9→8
5222 measured reflections	l = −27→27

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.036	Hydrogen site location: difference Fourier map
wR(F^2) = 0.086	H-atom parameters constrained
S = 0.89	w = 1/[σ^2(Fo^2) + (0.0452P)^2] where P = (Fo^2 + 2Fc^2)/3
1154 reflections	(Δ/σ)max < 0.001
79 parameters	Δρmax = 0.38 e Å^−3
0 restraints	Δρmin = −0.37 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Ni1	0.5000	0.5000	0.0000	0.02020 (18)
N1	0.5673 (3)	0.2643 (3)	0.02866 (11)	0.0251 (5)
H1	0.6211	0.1914	0.0028	0.030*
N2	0.5880 (4)	0.0103 (3)	0.09376 (12)	0.0312 (6)
H2A	0.6309	−0.0593	0.0652	0.037*
H2B	0.5727	−0.0354	0.1293	0.037*
N3	0.4786 (3)	0.2853 (3)	0.13157 (11)	0.0234 (5)
N4	0.4114 (3)	0.5607 (3)	0.07605 (10)	0.0266 (6)
H4	0.3587	0.6693	0.0790	0.032*
N5	0.3609 (3)	0.5446 (3)	0.17889 (11)	0.0305 (6)
H5A	0.3224	0.6590	0.1793	0.037*
H5B	0.3642	0.4812	0.2118	0.037*
C1	0.5444 (4)	0.1931 (4)	0.08282 (13)	0.0211 (6)
C2	0.4167 (4)	0.4636 (3)	0.12614 (13)	0.0221 (6)
O1W	0.6841 (3)	0.8073 (3)	0.21228 (10)	0.0432 (6)
H1W	0.7831	0.7900	0.1948	0.065*
H2W	0.6121	0.7220	0.2047	0.065*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0216 (3)	0.0207 (3)	0.0184 (3)	0.00268 (18)	0.0012 (2)	0.0006 (2)
N1	0.0311 (12)	0.0221 (11)	0.0222 (15)	0.0070 (10)	0.0038 (11)	−0.0015 (10)
N2	0.0420 (15)	0.0217 (11)	0.0297 (17)	0.0077 (10)	0.0095 (13)	0.0031 (10)
N3	0.0264 (13)	0.0222 (11)	0.0215 (14)	0.0032 (9)	0.0018 (10)	0.0006 (10)
N4	0.0322 (14)	0.0229 (11)	0.0247 (16)	0.0096 (11)	0.0043 (11)	−0.0005 (10)
N5	0.0456 (16)	0.0254 (12)	0.0204 (15)	0.0086 (11)	0.0054 (12)	0.0002 (10)
C1	0.0163 (13)	0.0220 (13)	0.0249 (17)	−0.0005 (10)	−0.0011 (11)	0.0009 (12)
C2	0.0186 (13)	0.0250 (13)	0.0226 (17)	0.0001 (11)	0.0004 (12)	−0.0004 (12)
O1W	0.0469 (13)	0.0443 (12)	0.0383 (15)	−0.0059 (10)	0.0080 (11)	−0.0081 (11)

Geometric parameters (Å, º)

Ni1—N4	1.849 (2)	N3—C1	1.347 (4)
Ni1—N4^i	1.849 (2)	N3—C2	1.349 (3)
Ni1—N1^i	1.859 (2)	N4—C2	1.311 (4)
Ni1—N1	1.859 (2)	N4—H4	0.8603
N1—C1	1.315 (4)	N5—C2	1.362 (4)
N1—H1	0.8606	N5—H5A	0.8596
N2—C1	1.362 (3)	N5—H5B	0.8596
N2—H2A	0.8590	O1W—H1W	0.8007
N2—H2B	0.8602	O1W—H2W	0.8066
N4—Ni1—N4^i	180.0	C2—N4—Ni1	129.85 (19)
N4—Ni1—N1^i	90.91 (11)	C2—N4—H4	115.1
N4^i—Ni1—N1^i	89.09 (11)	Ni1—N4—H4	115.0
N4—Ni1—N1	89.09 (11)	C2—N5—H5A	120.1
N4^i—Ni1—N1	90.91 (11)	C2—N5—H5B	120.0
N1^i—Ni1—N1	180.0	H5A—N5—H5B	120.0
C1—N1—Ni1	129.20 (19)	N1—C1—N3	125.9 (2)
C1—N1—H1	115.4	N1—C1—N2	120.4 (3)
Ni1—N1—H1	115.4	N3—C1—N2	113.6 (3)
C1—N2—H2A	120.0	N4—C2—N3	125.7 (3)
C1—N2—H2B	120.0	N4—C2—N5	119.8 (2)
H2A—N2—H2B	120.0	N3—C2—N5	114.5 (3)
C1—N3—C2	119.9 (2)	H1W—O1W—H2W	108.5

Symmetry code: (i) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H2W···N5	0.81	2.23	3.022 (3)	166
O1W—H1W···N3^ii	0.80	2.17	2.958 (3)	167
N5—H5B···O1W^iii	0.86	2.12	2.967 (3)	168
N5—H5A···N3^iv	0.86	2.52	3.106 (3)	127
N2—H2B···O1W^v	0.86	2.29	3.076 (4)	152
N2—H2A···N1^vi	0.86	2.58	3.306 (4)	143

Symmetry codes: (ii) −x+3/2, y+1/2, z; (iii) −x+1, y−1/2, −z+1/2; (iv) −x+1/2, y+1/2, z; (v) x, y−1, z; (vi) −x+3/2, y−1/2, z.