Tris(3,3′-diamino-2,2′-bipyridine)zinc(II) dinitrate

In the title complex, [Zn(C₁₀H₁₀N₄)₃](NO₃)₂, the six-coordin­ate Zn^II atom lies at the inter­section of three twofold axes in a slightly disorted octa­hedral coordination environment. The N atom of a nitrate anion is located on a threefold axis. In the crystal structure, inter­molecular N—H...N and N—H...O hydrogen bonds between cations and anions form a two-dimensional network perpendicular to the c axis.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.038
• wR factor = 0.081
• Data-to-parameter ratio = 13.7

checkCIF/PLATON results

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Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.65
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.13 Ratio

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           25.98
           From the CIF: _reflns_number_total               1072
           Count of symmetry unique reflns          601
           Completeness (_total/calc)            178.37%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       471
           Fraction of Friedel pairs measured     0.784
           Are heavy atom types Z>Si present        yes
PLAT794_ALERT_5_G Check Predicted Bond Valency for Zn1         (2)       1.83

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

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

2,2'-Bipyridine and its derivatives play a pivotal role in the area of modern coordination chemistry. For example, some dye-sensitized solar cells deal with complexes of derivatives of 2,2'-bispyridine as a ligand (Kuang et al., 2006). We have an interest in complexes containing 3,3'-diamino-2,2'-bipyridine and have synthesized the complexes containing Ni^II, Cd^II, Mn^II and Cu^II ions (Shi et al., 2006a,b; Min et al., 2006; Zhang et al., 2007). Here we report the structure of the title complex (Fig. 1).

The Zn^II atom, located on the intersection of a threefold axis and a twofold axis, assumes a slightly distorted octahedral ZnN₆ coordination geometry. The nitrate anion lies on a threefold axis. In the 3,3'-diamino-2,2'-bipyridine ligand, each pyridine ring is essentially planar with a maximum deviation of -0.029 (4) Å for atom C1; the dihedral angle between the two pyridine rings is 34.77 (18), which is larger than that in the Ni(II) complex, but smaller than that in Cd(II) and Mn(II) complexes. Just as with the Ni(II), Mn(II) and Cd(II) complexes the deviation from planarity in the title compound is expected in terms of steric relief. The hydrogen bonds (Table 1) that arise from nitrate anions and amino group result in the connection of the cations and the nitrate anions and contribute to the formation of a supermolecular two-dimensional sheet parallel ab plane, as shown in Fig. 2.

Related literature

For background information see: Kuang et al. (2006). For related structures, see: Shi et al. (2006a,b,c); Zhang et al. (2007).

S2. Experimental

Zn(NO₃)₂·6H₂O (0.0354 g, 0.119 mmol) in H₂O (10 ml) was added to 6,6'-diamino-2,2'-bipyridine (0.0110 g, 0.059 mmol) in acetonitrile (5 ml), and the solution was stirred for a few minutes. Colorless crystals were obtained after allowing the solution to stand at room temperature for one week. The infrared stretching vibrations of pyridine ring and amino groups appeared at 1638 cm^-1, 1465 cm^-1 and 1384 cm^-1.

S3. Refinement

The H atoms were placed in calculated positions and refined as riding, with C—H = 0.93 Å, U_iso(H) = 1.2_eq(C); N—H = 0.86 Å, U_iso(H) = 1.2_eq(N) for amino group.

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXTL (Bruker, 2001); program(s) used to refine structure: SHELXTL (Bruker, 2001); molecular graphics: SHELXTL (Bruker, 2001); software used to prepare material for publication: SHELXTL (Bruker, 2001).

Figures

	Fig. 1. The molecular structure showing the atom numbering scheme with thermal ellipsoids drawn at the 30% probability level. [Symmetry codes: (i) x - y + 1, -y + 2, -z; (ii) -y + 1, x - y + 2, z; (iii) -x + y - 1, -x + 1, z; (iv) y - 1, x + 1, -z; (v) -x, -x + y, -z; (vi) -y + 1, x - y + 1, z; (vii) -x + y, -x + 1, z]. Only one of the two nitrate anions in the formula unit is showm.
	Fig. 2. Part of the crystal structure with hydrogen bonds shown as dashed lines.

Tris(3,3'-diamino-2,2'-bipyridine)zinc(II) bis(nitrate)

Crystal data

[Zn(C10H10N4)3](NO3)2	Dx = 1.527 Mg m^−3
Mr = 748.05	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R32	Cell parameters from 918 reflections
Hall symbol: R 3 2"	θ = 2.2–19.0°
a = 14.6116 (19) Å	µ = 0.82 mm^−1
c = 13.199 (4) Å	T = 298 K
V = 2440.4 (8) Å^3	Prism, colourless
Z = 3	0.20 × 0.14 × 0.10 mm
F(000) = 1158

Data collection

Bruker SMART APEX CCD diffractometer	1072 independent reflections
Radiation source: fine-focus sealed tube	1005 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.051
φ and ω scans	θmax = 26.0°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −18→10
Tmin = 0.853, Tmax = 0.922	k = −15→18
4419 measured reflections	l = −16→15

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.038	H-atom parameters constrained
wR(F^2) = 0.081	w = 1/[σ^2(Fo^2) + (0.0391P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max < 0.001
1072 reflections	Δρmax = 0.49 e Å^−3
78 parameters	Δρmin = −0.18 e Å^−3
0 restraints	Absolute structure: Flack (1983), with 469 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.03 (2)

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
Zn1	0.0000	1.0000	0.0000	0.0332 (2)
N2	0.0862 (2)	0.9399 (2)	0.08301 (16)	0.0354 (6)
C5	0.1754 (2)	0.9566 (2)	0.0369 (2)	0.0363 (7)
C3	0.1693 (4)	0.8141 (4)	0.1330 (2)	0.0585 (9)
H3	0.1969	0.7711	0.1505	0.070*
C1	0.0411 (3)	0.8668 (3)	0.1543 (3)	0.0487 (8)
H1	−0.0206	0.8564	0.1851	0.058*
C2	0.0846 (3)	0.8054 (3)	0.1838 (3)	0.0593 (10)
H2	0.0559	0.7588	0.2380	0.071*
C4	0.2154 (3)	0.8876 (2)	0.0541 (3)	0.0478 (8)
N1	0.3333	0.6667	0.0452 (2)	0.0415 (8)
O1	0.3647 (2)	0.6020 (2)	0.04535 (17)	0.0631 (7)
N3	0.2931 (3)	0.8874 (3)	−0.0037 (3)	0.0721 (10)
H3A	0.3133	0.8425	0.0085	0.087*
H3B	0.3217	0.9323	−0.0522	0.087*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.0295 (3)	0.0295 (3)	0.0407 (4)	0.01473 (14)	0.000	0.000
N2	0.0331 (16)	0.0286 (15)	0.0419 (12)	0.0135 (13)	0.0018 (12)	0.0051 (12)
C5	0.0318 (15)	0.0314 (16)	0.0463 (18)	0.0163 (13)	−0.0014 (13)	−0.0018 (13)
C3	0.065 (3)	0.044 (2)	0.077 (2)	0.0356 (19)	−0.006 (3)	0.011 (2)
C1	0.051 (2)	0.047 (2)	0.0494 (19)	0.0249 (16)	0.0071 (15)	0.0095 (15)
C2	0.073 (3)	0.048 (2)	0.059 (2)	0.031 (2)	−0.0009 (19)	0.0202 (17)
C4	0.0407 (19)	0.0358 (17)	0.069 (2)	0.0204 (15)	−0.0072 (16)	−0.0034 (16)
N1	0.0402 (13)	0.0402 (13)	0.044 (2)	0.0201 (7)	0.000	0.000
O1	0.0538 (17)	0.0466 (17)	0.0985 (16)	0.0322 (15)	0.0023 (13)	0.0010 (13)
N3	0.062 (2)	0.059 (2)	0.116 (3)	0.0456 (18)	0.022 (2)	0.0168 (19)

Geometric parameters (Å, º)

Zn1—N2^i	2.159 (2)	C3—C4	1.404 (5)
Zn1—N2^ii	2.159 (2)	C3—H3	0.9300
Zn1—N2^iii	2.159 (2)	C1—C2	1.390 (5)
Zn1—N2^iv	2.159 (2)	C1—H1	0.9300
Zn1—N2	2.159 (2)	C2—H2	0.9300
Zn1—N2^v	2.159 (2)	C4—N3	1.368 (4)
N2—C1	1.325 (4)	N1—O1^vi	1.239 (2)
N2—C5	1.345 (4)	N1—O1^vii	1.239 (2)
C5—C4	1.414 (4)	N1—O1	1.239 (2)
C5—C5^iii	1.467 (6)	N3—H3A	0.8600
C3—C2	1.357 (5)	N3—H3B	0.8600
N2^i—Zn1—N2^ii	169.86 (16)	C4—C5—C5^iii	124.6 (2)
N2^i—Zn1—N2^iii	96.53 (8)	C2—C3—C4	120.3 (3)
N2^ii—Zn1—N2^iii	91.45 (14)	C2—C3—H3	119.8
N2^i—Zn1—N2^iv	96.53 (8)	C4—C3—H3	119.8
N2^ii—Zn1—N2^iv	76.28 (14)	N2—C1—C2	121.1 (3)
N2^iii—Zn1—N2^iv	96.53 (8)	N2—C1—H1	119.5
N2^i—Zn1—N2	91.45 (14)	C2—C1—H1	119.5
N2^ii—Zn1—N2	96.53 (8)	C3—C2—C1	119.4 (3)
N2^iii—Zn1—N2	76.28 (14)	C3—C2—H2	120.3
N2^iv—Zn1—N2	169.86 (16)	C1—C2—H2	120.3
N2^i—Zn1—N2^v	76.28 (14)	N3—C4—C3	119.5 (3)
N2^ii—Zn1—N2^v	96.53 (8)	N3—C4—C5	123.5 (3)
N2^iii—Zn1—N2^v	169.86 (16)	C3—C4—C5	117.0 (3)
N2^iv—Zn1—N2^v	91.45 (14)	O1^vi—N1—O1^vii	120.000 (2)
N2—Zn1—N2^v	96.53 (8)	O1^vi—N1—O1	120.000 (2)
C1—N2—C5	120.9 (3)	O1^vii—N1—O1	120.000 (3)
C1—N2—Zn1	122.1 (2)	C4—N3—H3A	120.0
C5—N2—Zn1	113.92 (18)	C4—N3—H3B	120.0
N2—C5—C4	120.4 (3)	H3A—N3—H3B	120.0
N2—C5—C5^iii	114.69 (17)
N2^ii—Zn1—N2—C1	101.6 (2)	C5—N2—C1—C2	0.2 (5)
N2^iii—Zn1—N2—C1	−168.5 (3)	Zn1—N2—C1—C2	159.3 (3)
N2^v—Zn1—N2—C1	4.2 (3)	C4—C3—C2—C1	2.7 (6)
N2^ii—Zn1—N2—C5	−98.0 (3)	N2—C1—C2—C3	−5.7 (6)
N2^iii—Zn1—N2—C5	−8.12 (15)	C2—C3—C4—N3	−172.8 (4)
N2^v—Zn1—N2—C5	164.6 (2)	C2—C3—C4—C5	5.2 (6)
C1—N2—C5—C4	8.2 (4)	N2—C5—C4—N3	167.3 (3)
Zn1—N2—C5—C4	−152.5 (2)	C5^iii—C5—C4—N3	−6.8 (5)
C1—N2—C5—C5^iii	−177.2 (3)	N2—C5—C4—C3	−10.7 (5)
Zn1—N2—C5—C5^iii	22.1 (4)	C5^iii—C5—C4—C3	175.2 (4)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3A···O1^vii	0.86	2.14	2.980 (4)	167
N3—H3B···N3^iii	0.86	2.40	2.851 (6)	113

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