Silver(I) sulfate coordination polymers with 4,4′-bipyridazine and pyridazino[4,5-d]pyridazine

Poly[[μ₄-4,4′-bipyridazine-μ₅-sulfato-disilver(I)] mono­hy­drate], {[Ag₂(SO₄)(C₈H₆N₄)]·H₂O}_n, (I), and poly[[aqua-μ₄-­pyridazino[4,5-d]pyridazine-μ₃-sulfato-disilver(I)] mono­hydrate], {[Ag₂(SO₄)(C₆H₄N₄)(H₂O)]·H₂O}_n, (II), possess three- and two-dimensional polymeric structures, respectively, supported by N-tetra­dentate coordination of the organic ligands [Ag—N = 2.208 (3)–2.384 (3) Å] and O-penta­dentate coordination of the sulfate anions [Ag—O = 2.284 (3)–2.700 (2) Å]. Compound (I) is the first structurally examined complex of the new ligand 4,4′-bipyridazine; it is based upon unprecedented centrosymmetric silver–pyridazine tetra­mers with tetra­hedral AgN₂O₂ and trigonal–bipyramidal AgN₂O₃ coordination of two independent Ag^I ions. Compound (II) adopts a typical dimeric silver–pyridazine motif incorporating two kinds of square-pyramidal AgN₂O₃ Ag^I ions. The structure exhibits short anion–π inter­actions involving noncoordinated sulfate O atoms [O...π = 3.041 (3) Å].

S1. Comment

Pyridazine is an efficient bitopic N-donor ligand towards metal ions, yielding a variety of molecular, discrete polynuclear or infinite coordination patterns. Very rich and versatile possibilities for the synthesis of coordination compounds may be found for pyridazine-bridged Cu^I and Ag^I cations, the extremely soft acids favouring coordination to unsaturated N atoms (Munakata et al., 1999). Many characteristic and readily predictable polynuclear (Maekawa et al., 1994), chain-like or helical (Plasseraud et al., 2001) copper(I) and silver(I) pyridazine motifs may be applicable for the development of complicated metal–organic frameworks as simpler subunits of the structure. Therefore, organic ligands combining multiple pyridazine donor groups provide special potential for crystal structure design. Recently, we have reported the utility of condensed pyridazines for the generation of chiral channelled crystals (Solntsev, Sieler, Krautscheid & Domasevitch, 2004), three-dimensional arrays supporting giant cavities (Solntsev, Sieler, Chernega et al., 2004) and frameworks with special anion-binding properties (Gural'skiy, et al., 2006). However, the chemistry of such systems is practically unexplored, although many types of pyridazines are readily available and inexpensive species. In this context, we have prepared two new siver(I) sulfate complexes with illustrative organic connectors, which combine the set of pyridazine donor functions either by coupling [4,4'-bipyridazine, compound (I)] or by annelation [pyridazino[4,5-d]pyridazine, compound (II)].

In compounds (I) and (II), the organic ligands utilize all available N-donor functions for coordination and act entirely as tetradentate bridges. The sulfate anions are pentadentate towards Ag^I ions in both structures, which has only one structural precedent, in the silver sulfate complex with 1,2-di(2-pyridyl)ethylene (Tong et al., 2002).

The metal–organic pattern in the 4,4'-bipyridazine complex, (I), exists as a centrosymmetric tetramer (Fig. 1), which is an unprecedented feature of silver–pyridazine systems. The fourfold nearly tetrahedral coordination environment of the Ag2 atoms is typical. It involves two short Ag—N bonds [2.208 (3) and 2.234 (3) Å] and two longer Ag—O bonds (Table 1), which are characteristic of Ag^I ions coordinated by a set of N,O-donor ligands (Khlobystov et al., 2001). The coordination of the Ag1 atoms is slightly unusual: the shortest bond is Ag1—O1 [2.284 (3) Å versus Ag1—N 2.319 (3) and 2.384 (3) Å)], and two appreciably distal O atoms complete the distorted trigonal–bipyramidal environment (Table 1).

4,4'-Bipyridazine bridges connect the silver tetramers into simple chains along the [111] direction in the crystal structure (distance between the centroids of the tetramers = 11.36 Å) and further aggregation into a three-dimensional structure occurs by means of pentadentate bridging sulfate groups. Sulfate atoms O1 and O2 are coordinated to two Ag^I ions [Ag1 and Ag1(1 - x, -y, 1 - z), and Ag2 and Ag2(1 - x, 1 - y, 1 - z), respectively] and they form centrosymmetric Ag₂O₂ rhombs (Fig. 2) uniting the metal–organic chains into layers. Comparable structural functions of sulfate ions were also observed in the complex with 1,3-dithiane, with Ag—O bond lengths in the range 2.49–2.53 Å (Brammer et al., 2002). Relatively distal secondary interactions connect adjacent layers [Ag1—O3(-x, -y, 1 - z) = 2.598 (3) Å] (Fig. 3). Sulfate atom O4 remains noncoordinated and is involved in strong hydrogen bonding with the solvent water molecules, which results in the formation of very typical aqua–anion dimers (Fig. 3) (Domasevitch & Boldog, 2005). Each of the available CH groups forms additional weak hydrogen bonds (Table 2), while two C1–C4/N1/N2 rings of the organic molecules [related by the symmetry operation (1 - x, -y, -z)] afford slipped π–π stacking, with centroid-to-centroid and interplanar distances of 3.668 (2) and 3.323 (3) Å, respectively, and a slippage angle (angle subtended by the intercentroid vector to the plane normal) of 25.0 (2)° (Janiak, 2000).

In the structure of compound (II), the Ag^I ions and organic ligands are assembled into dimers (Fig. 4). This coordination pattern is very characteristic of pyridazines and has been observed for silver nitrate complexes with pyridazine (Carlucci et al., 1997) and phthalazine (Tsuda et al., 1989) and a silver phthalate complex with phthalazine (Whitcomb & Rogers, 1997). Each of the two unique Ag^I ions forms two short Ag—N bonds [2.270 (2)–2.335 (2) Å; Table 3] and the distorted square-pyramidal fivefold coordination is completed by three longer Ag—O [2.404 (2)–2.700 (2) Å] interactions with sulfate ions (Ag1) and with a sulfate ion and a water molecule (Ag2). The tetradentate bridging function of the ligands results in the formation of infinite metal–organic ribbons along the c axis, which are linked by pentadentate sulfate ions (Fig. 5), yielding layers parallel to the bc plane. Within the coordination layer, two metal–organic ribbons [related by the symmetry operation (-x, 1 - y, 1 - z)] are situated on top of one another and the ligands afford tight π–π stacking (Fig. 6). This interaction occurs with an appreciably short interplanar distance of 3.369 (2) Å [centroid-to-centroid distance 3.6791 (15) Å], but with a relatively high slippage angle of the interacting groups [23.7 (2)°], which is typical for slipped π–π contacts of electron-deficient heteroaromatic rings (Janiak, 2000).

Adjacent layers, which are related by translation along the a axis, are held together by hydrogen bonding involving the sulfate ions and coordinated (O5) and non-coordinated (O6) water molecules. One of these hydrogen bonds is three-centred (Table 4, Fig. 6). Within the set of weak interlayer forces, however, the most notable interaction is a very unusual stacking between the aromatic π-cloud (atoms N3/N4/C6/C3/C2/C5) and sulfate atom O3(1 - x, 1 - y, 1 - z) [group centroid···O distance = 3.041 (3) Å, angle of the O···π axis to the plane of the aromatic cycle = 82.8 (1)°]. A slightly shorter contact of this type was also observed in the zinc(II) and copper(II) nitrate complexes (O···π = 2.83 and 2.87 Å, respectively; Gural'skiy et al., 2006). Such close and directional interaction with a negatively polarized atom clearly reflects the pronounced electron-deficient character of the ligand. Indeed, the bicyclic system of pyridazine rings sharing their d edge even exhibits appreciable azadiene reactivity similar to 1,2,4,5-tetrazine (Haider, 1991). The parameters for the close anion–π interaction in (II) are comparable with those observed for most electron-deficient systems, such as 1,3,5-triazines (Maheswari et al., 2006) and 1,2,4,5-tetrazines (Schottel et al., 2006) [F(O)···π = 2.80–3.20 Å].

It is worth noting that structure (I) displays no anion–π interactions. This may be attributed to the significantly higher lowest unoccupied molecular orbital energy of the pyridazine system compared with pyridazino[4,5-d]pyridazine (-0.288 and -1.591 eV, respectively; Haider, 1991). The structure of the organic ligands in (I) and (II) reveals a somewhat lower delocalization of π-electron density within the frame of condensed pyridazine and an appreciable contribution of the bis(azadiene) resonance structure (e.g. –C═N—N═C–). Thus, the N—N bonds in the molecule of pyridazino[4,5-d]pyridazine are longer than in 4,4'-bipyridazine [1.375 (3) and 1.379 (3) Å versus 1.348 (4) and 1.350 (4) Å], while all C—N bond lengths are shorter [1.305 (3)–1.308 (3) versus 1.324 (4)–1.332 (4) Å]. Coordination to many metal ions is also of importance for the electronic structure of the ligand, since in noncoordinated pyridazino[4,5-d]pyridazine the C—N bonds are certainly longer (1.310 and 1.314 A; Sabelli et al., 1969).

In the molecule of 4,4'-bipyridazine, the C2—C6 bond [1.479 (4) Å] between the rings is characteristic of a single bond between two Csp² atoms and this indicates a lack of conjugation between the pyridazine rings. The molecule is not planar and it possesses a slightly twisted conformation, with a dihedral angle between the two pyridazine rings of 22.3 (3)° [torsion angle C3—C2—C6—C7 = 22.7 (5)°]. The pyridazine rings adopt a cis configuration, which is important for the organization of simpler metal–organic chains instead of the four-connected network.

In conclusion, either condensed pyridazino[4,5-d]pyridazine or 4,4'-bipyridazine reveal a maximal tetradentate function towards Ag^I ions, even in combination with nucleophilic sulfate counteranions. The structures reported in this paper could provide attractive prototypes for the design of solid-state architecture using `double pyridazine' ligands.

Related literature

For related literature, see: Brammer et al. (2002); Carlucci et al. (1997); Domasevitch & Boldog (2005); Gural'skiy, Solntsev, Krautscheid & Domasevitch (2006); Haider (1991); Janiak (2000); Khlobystov et al. (2001); Maekawa et al. (1994); Maheswari et al. (2006); Munakata et al. (1999); Plasseraud et al. (2001); Sabelli et al. (1969); Schottel et al. (2006); Solntsev, Sieler, Chernega, Howard, Gelbrich & Domasevitch (2004); Solntsev, Sieler, Krautscheid & Domasevitch (2004); Tong et al. (2002); Tsuda et al. (1989); Whitcomb & Rogers (1997).

S2. Experimental

Pyridazino[4,5-d]pyridazine was prepared with 1,2,4,5-tetrazine as starting material, in accordance with the literature method of Gural'skiy et al. (2006). For the preparation of complex (I), solid silver sulfate (0.062 g, 0.1 mmol) was added to a solution of 4,4'-bipyridazine (0.032 g, 0.2 mmol) in water (3 ml). The mixture was allowed to stand for 7–8 d until total dissolution of Ag₂SO₄ was observed, which was accompanied by crystallization of complex (I) as yellow prisms (yield 0.078 g, 80%). In the same manner, compound (II) (yellow blocks) was synthesized in 70% yield starting with a solution of pyridazino[4,5-d]pyridazine (0.026 g, 0.2 mmol) in water (3 ml).

S3. Refinement

H atoms were placed in geometrically idealized positions and treated as riding, with O—H = 0.85 Å and C—H = 0.96 Å, and with U_iso(H) = 1.2U_eq(C) or 1.5U_eq(O). [Please check added text]

Computing details

For both compounds, data collection: SMART-NT (Bruker, 1998); cell refinement: SAINT-NT (Bruker, 1999); data reduction: SAINT-NT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Version 1.700.00; Farrugia, 1999).

Figures

	Fig. 1. The structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 45% probability level and H atoms are shown as small spheres of arbitrary radii. Dashed lines indicate hydrogen bonds. [Symmetry codes: (i) -x, 1 - y, -z; (iii) 1 - x, -y, 1 - z; (iv) 1 + x, y - 1, 1 + z; (v) 1 - x, -1 - y, 1 - z.]
	Fig. 2. A view of two metal–organic chains in the structure of (I), showing the bridging function of the sulfate O atoms (O2) between the two silver–bipyridazine tetramers. [Symmetry codes: (iii) 1 - x, -y, 1 - z; (v) 1 - x, -1 - y, 1 - z.]
	Fig. 3. The interconnection of the silver–pyridazine tetramers in the structure of (I) via Ag1—O3^i [Should this be Ag1—O3^ii?] coordination bonds and hydrogen bonding with solvent water molecules. [Symmetry codes: (ii) -x, -y, 1 - z; (iii) 1 - x, -y, 1 - z.] [Symmetry code iii not visible - can it be omitted from the caption?]
	Fig. 4. The structure of (II), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 40% probability level and H atoms are shown as small spheres of arbitrary radii. Dashed lines indicate hydrogen bonds. [Symmetry codes: (i) x, y, 1 + z; (ii) x, y - 1, z.]
	Fig. 5. The coordination environment of the two unique Ag ions and the pentadentate bridging function of the sulfate ions in the structure of (II). [Symmetry codes: (i) x, y, 1 + z; (ii) x, y - 1, z; (iii) -x, 1 - y, 2 - z; (iv) x, 1 + y, z.]
	Fig. 6. Interlayer interactions in the structure of (II), showing the hydrogen-bonding scheme with coordinated (O5) and noncoordinated (O6) water molecules, and the close anion–π interactions of the noncoordinated sulfate O atoms (O3). [Symmetry codes: (ii) x, y - 1, z; (v) 1 - x, 1 - y, 2 - z; (vi) 1 - x, 1 - y, 1 - z.]

(I) Poly[[µ₄-4,4'-bipyridazine-µ₅-sulfato-disilver(I)] monohydrate]

Crystal data

[Ag2(SO4)(C8H4N4)]·H2O	Z = 2
Mr = 487.98	F(000) = 468
Triclinic, P1	Dx = 2.785 Mg m^−3
a = 7.4829 (9) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.4881 (10) Å	Cell parameters from 2629 reflections
c = 10.9267 (10) Å	θ = 3.0–27.5°
α = 67.172 (9)°	µ = 3.57 mm^−1
β = 88.971 (8)°	T = 213 K
γ = 67.092 (8)°	Prism, yellow
V = 581.93 (13) Å^3	0.20 × 0.18 × 0.14 mm

Data collection

Siemens SMART CCD area-detector diffractometer	2629 independent reflections
Radiation source: fine-focus sealed tube	2265 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.022
ω scans	θmax = 27.5°, θmin = 3.0°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −9→9
Tmin = 0.514, Tmax = 0.609	k = −11→11
5496 measured reflections	l = −14→14

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.073	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0459P)^2 + 0.481P] where P = (Fo^2 + 2Fc^2)/3
2629 reflections	(Δ/σ)max = 0.001
181 parameters	Δρmax = 1.17 e Å^−3
0 restraints	Δρmin = −0.98 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
Ag1	0.24328 (5)	0.14112 (4)	0.37790 (3)	0.03080 (10)
Ag2	0.59227 (4)	−0.32127 (4)	0.43271 (2)	0.02725 (10)
S1	0.32180 (12)	−0.24191 (11)	0.66688 (8)	0.01918 (17)
O1	0.3808 (5)	−0.0890 (5)	0.5889 (3)	0.0512 (9)
O2	0.3857 (5)	−0.3841 (5)	0.6118 (3)	0.0419 (7)
O3	0.1108 (5)	−0.1699 (5)	0.6647 (4)	0.0514 (9)
O4	0.4216 (5)	−0.3253 (5)	0.8057 (3)	0.0385 (7)
O5	0.2397 (5)	−0.4842 (5)	1.0060 (3)	0.0407 (7)
H1W	0.3002	−0.4375	0.9456	0.061*
H2W	0.3140	−0.5394	1.0814	0.061*
N1	0.2939 (4)	0.0364 (4)	0.2016 (3)	0.0194 (5)
N2	0.4177 (4)	−0.1429 (4)	0.2298 (3)	0.0191 (5)
N3	−0.0995 (4)	0.5385 (4)	−0.3213 (3)	0.0199 (6)
N4	−0.1510 (4)	0.4752 (4)	−0.4047 (3)	0.0197 (6)
C1	0.1905 (5)	0.1462 (4)	0.0795 (3)	0.0200 (6)
H1	0.1014	0.2726	0.0622	0.024*
C2	0.2035 (5)	0.0883 (4)	−0.0265 (3)	0.0158 (6)
C3	0.3267 (5)	−0.0967 (4)	0.0042 (3)	0.0199 (6)
H3	0.3410	−0.1476	−0.0618	0.024*
C4	0.4299 (5)	−0.2075 (4)	0.1352 (3)	0.0205 (6)
H4	0.5140	−0.3370	0.1581	0.025*
C5	0.0196 (5)	0.4157 (5)	−0.2055 (3)	0.0196 (6)
H5	0.0603	0.4630	−0.1495	0.024*
C6	0.0885 (5)	0.2205 (4)	−0.1616 (3)	0.0166 (6)
C7	0.0423 (5)	0.1582 (4)	−0.2510 (3)	0.0190 (6)
H7	0.0911	0.0265	−0.2299	0.023*
C8	−0.0771 (5)	0.2924 (5)	−0.3726 (3)	0.0208 (6)
H8	−0.1074	0.2504	−0.4362	0.025*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ag1	0.04223 (19)	0.02025 (15)	0.01970 (15)	−0.00635 (12)	−0.00770 (12)	−0.00431 (11)
Ag2	0.02685 (16)	0.02754 (15)	0.01239 (13)	−0.00220 (11)	−0.00765 (10)	−0.00220 (10)
S1	0.0212 (4)	0.0197 (4)	0.0135 (3)	−0.0072 (3)	0.0000 (3)	−0.0048 (3)
O1	0.0448 (19)	0.0458 (18)	0.0402 (17)	−0.0310 (16)	−0.0166 (14)	0.0179 (14)
O2	0.0429 (18)	0.0462 (17)	0.0406 (16)	−0.0090 (14)	0.0045 (13)	−0.0315 (14)
O3	0.0257 (16)	0.058 (2)	0.091 (3)	−0.0164 (15)	0.0140 (16)	−0.052 (2)
O4	0.0548 (19)	0.0538 (18)	0.0120 (11)	−0.0324 (16)	0.0003 (12)	−0.0085 (12)
O5	0.0354 (16)	0.0510 (18)	0.0257 (14)	−0.0213 (14)	0.0027 (12)	−0.0025 (13)
N1	0.0189 (13)	0.0186 (13)	0.0143 (12)	−0.0022 (11)	−0.0016 (10)	−0.0059 (10)
N2	0.0191 (13)	0.0167 (12)	0.0125 (12)	−0.0029 (10)	−0.0026 (10)	−0.0016 (10)
N3	0.0229 (15)	0.0197 (13)	0.0128 (12)	−0.0070 (11)	−0.0032 (10)	−0.0038 (10)
N4	0.0218 (14)	0.0226 (14)	0.0116 (12)	−0.0080 (11)	−0.0010 (10)	−0.0050 (11)
C1	0.0240 (16)	0.0152 (14)	0.0123 (14)	−0.0024 (12)	−0.0025 (12)	−0.0026 (11)
C2	0.0163 (15)	0.0162 (14)	0.0108 (13)	−0.0056 (12)	−0.0029 (11)	−0.0024 (11)
C3	0.0235 (17)	0.0177 (15)	0.0162 (15)	−0.0049 (13)	−0.0012 (12)	−0.0083 (12)
C4	0.0207 (16)	0.0157 (14)	0.0146 (14)	−0.0004 (12)	−0.0042 (12)	−0.0029 (12)
C5	0.0241 (17)	0.0200 (15)	0.0111 (13)	−0.0071 (13)	−0.0048 (12)	−0.0046 (12)
C6	0.0171 (15)	0.0169 (14)	0.0102 (13)	−0.0038 (12)	−0.0005 (11)	−0.0033 (11)
C7	0.0204 (16)	0.0169 (14)	0.0163 (14)	−0.0053 (12)	−0.0012 (12)	−0.0060 (12)
C8	0.0215 (17)	0.0257 (16)	0.0147 (15)	−0.0084 (13)	−0.0010 (12)	−0.0091 (13)

Geometric parameters (Å, º)

Ag1—O1	2.284 (3)	N2—C4	1.332 (4)
Ag1—N3^i	2.319 (3)	N3—C5	1.332 (4)
Ag1—N1	2.385 (3)	N3—N4	1.350 (4)
Ag1—O3^ii	2.598 (3)	N4—C8	1.324 (4)
Ag1—O1^iii	2.680 (3)	C1—C2	1.412 (4)
Ag2—N2	2.208 (3)	C1—H1	0.9600
Ag2—N4^iv	2.234 (3)	C2—C3	1.380 (4)
Ag2—O2	2.495 (3)	C2—C6	1.479 (4)
Ag2—O2^v	2.672 (3)	C3—C4	1.399 (4)
S1—O3	1.451 (3)	C3—H3	0.9600
S1—O2	1.466 (3)	C4—H4	0.9600
S1—O4	1.468 (3)	C5—C6	1.403 (4)
S1—O1	1.476 (3)	C5—H5	0.9600
O5—H1W	0.8500	C6—C7	1.382 (4)
O5—H2W	0.8500	C7—C8	1.392 (4)
N1—C1	1.326 (4)	C7—H7	0.9600
N1—N2	1.348 (4)	C8—H8	0.9600
O1—Ag1—N3^i	125.75 (13)	N1—N2—Ag2	118.7 (2)
O1—Ag1—N1	115.15 (13)	C5—N3—N4	119.5 (3)
N3^i—Ag1—N1	118.59 (9)	C5—N3—Ag1^i	122.2 (2)
O1—Ag1—O3^ii	106.76 (13)	N4—N3—Ag1^i	118.15 (19)
N3^i—Ag1—O3^ii	86.34 (11)	C8—N4—N3	119.6 (3)
N1—Ag1—O3^ii	83.56 (11)	C8—N4—Ag2^vi	121.8 (2)
O1—Ag1—O1^iii	73.57 (12)	N3—N4—Ag2^vi	117.2 (2)
N3^i—Ag1—O1^iii	97.76 (11)	N1—C1—C2	123.9 (3)
N1—Ag1—O1^iii	91.52 (11)	N1—C1—H1	118.0
O3^ii—Ag1—O1^iii	174.71 (11)	C2—C1—H1	118.0
N2—Ag2—N4^iv	160.29 (10)	C3—C2—C1	116.2 (3)
N2—Ag2—O2	112.90 (11)	C3—C2—C6	122.8 (3)
N4^iv—Ag2—O2	85.79 (10)	C1—C2—C6	121.0 (3)
N2—Ag2—O2^v	86.93 (10)	C2—C3—C4	117.6 (3)
N4^iv—Ag2—O2^v	86.32 (10)	C2—C3—H3	121.2
O2—Ag2—O2^v	91.57 (9)	C4—C3—H3	121.2
O3—S1—O2	110.26 (19)	N2—C4—C3	123.6 (3)
O3—S1—O4	109.5 (2)	N2—C4—H4	118.2
O2—S1—O4	109.64 (19)	C3—C4—H4	118.2
O3—S1—O1	111.0 (2)	N3—C5—C6	123.2 (3)
O2—S1—O1	109.5 (2)	N3—C5—H5	118.4
O4—S1—O1	106.83 (18)	C6—C5—H5	118.4
S1—O1—Ag1	127.49 (19)	C7—C6—C5	116.4 (3)
S1—O2—Ag2	112.59 (19)	C7—C6—C2	121.7 (3)
S1—O3—Ag1^ii	156.83 (19)	C5—C6—C2	121.8 (3)
H1W—O5—H2W	108.4	C6—C7—C8	117.9 (3)
C1—N1—N2	119.5 (3)	C6—C7—H7	121.0
C1—N1—Ag1	121.1 (2)	C8—C7—H7	121.0
N2—N1—Ag1	119.15 (19)	N4—C8—C7	123.1 (3)
C4—N2—N1	119.2 (3)	N4—C8—H8	118.5
C4—N2—Ag2	122.0 (2)	C7—C8—H8	118.5
O3—S1—O1—Ag1	−47.7 (4)	O2^v—Ag2—N2—C4	−23.3 (3)
O2—S1—O1—Ag1	74.2 (3)	N4^iv—Ag2—N2—N1	−133.8 (3)
O4—S1—O1—Ag1	−167.1 (3)	O2—Ag2—N2—N1	65.7 (3)
N3^i—Ag1—O1—S1	119.6 (3)	O2^v—Ag2—N2—N1	156.1 (2)
N1—Ag1—O1—S1	−68.8 (3)	C5—N3—N4—C8	−2.4 (5)
O3^ii—Ag1—O1—S1	21.9 (3)	Ag1^i—N3—N4—C8	−177.5 (2)
O1^iii—Ag1—O1—S1	−152.6 (4)	C5—N3—N4—Ag2^vi	164.3 (2)
O3—S1—O2—Ag2	128.7 (2)	Ag1^i—N3—N4—Ag2^vi	−10.8 (3)
O4—S1—O2—Ag2	−110.63 (19)	N2—N1—C1—C2	−1.1 (5)
O1—S1—O2—Ag2	6.3 (2)	Ag1—N1—C1—C2	−175.4 (3)
N2—Ag2—O2—S1	−89.45 (19)	N1—C1—C2—C3	2.7 (5)
N4^iv—Ag2—O2—S1	97.03 (19)	N1—C1—C2—C6	−177.9 (3)
O2^v—Ag2—O2—S1	−176.8 (2)	C1—C2—C3—C4	−1.5 (5)
O2—S1—O3—Ag1^ii	1.5 (7)	C6—C2—C3—C4	179.1 (3)
O4—S1—O3—Ag1^ii	−119.2 (7)	N1—N2—C4—C3	2.9 (5)
O1—S1—O3—Ag1^ii	123.1 (7)	Ag2—N2—C4—C3	−177.7 (3)
O1—Ag1—N1—C1	166.1 (3)	C2—C3—C4—N2	−1.2 (5)
N3^i—Ag1—N1—C1	−21.7 (3)	N4—N3—C5—C6	−3.2 (5)
O3^ii—Ag1—N1—C1	60.6 (3)	Ag1^i—N3—C5—C6	171.8 (2)
O1^iii—Ag1—N1—C1	−121.4 (3)	N3—C5—C6—C7	6.2 (5)
O1—Ag1—N1—N2	−8.2 (3)	N3—C5—C6—C2	−173.5 (3)
N3^i—Ag1—N1—N2	164.0 (2)	C3—C2—C6—C7	22.7 (5)
O3^ii—Ag1—N1—N2	−113.7 (3)	C1—C2—C6—C7	−156.6 (3)
O1^iii—Ag1—N1—N2	64.3 (2)	C3—C2—C6—C5	−157.7 (3)
C1—N1—N2—C4	−1.7 (5)	C1—C2—C6—C5	23.0 (5)
Ag1—N1—N2—C4	172.7 (2)	C5—C6—C7—C8	−3.7 (5)
C1—N1—N2—Ag2	178.9 (2)	C2—C6—C7—C8	175.9 (3)
Ag1—N1—N2—Ag2	−6.7 (3)	N3—N4—C8—C7	4.7 (5)
N4^iv—Ag2—N2—C4	46.8 (5)	Ag2^vi—N4—C8—C7	−161.3 (3)
O2—Ag2—N2—C4	−113.7 (3)	C6—C7—C8—N4	−1.5 (5)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H1W···O4	0.85	1.89	2.737 (4)	177
O5—H2W···O4^vii	0.85	1.99	2.773 (4)	152
C1—H1···O5^ii	0.96	2.40	3.210 (5)	142
C3—H3···O4^viii	0.96	2.39	3.334 (4)	169
C4—H4···O4^v	0.96	2.58	3.462 (5)	153
C5—H5···O5^ix	0.96	2.46	3.395 (5)	166
C7—H7···O3^viii	0.96	2.33	3.120 (4)	139
C8—H8···O2^x	0.96	2.43	3.164 (5)	133

Symmetry codes: (ii) −x, −y, −z+1; (v) −x+1, −y−1, −z+1; (vii) −x+1, −y−1, −z+2; (viii) x, y, z−1; (ix) x, y+1, z−1; (x) −x, −y, −z.

(II) Poly[[aqua-µ₄-pyridazino[4,5-d]pyridazine-µ₃-sulfato-disilver(I)] monohydrate]

Crystal data

[Ag2(SO4)(C6H4N4)(H2O)]·H2O	Z = 2
Mr = 479.96	F(000) = 460
Triclinic, P1	Dx = 2.715 Mg m^−3
a = 8.3733 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.7790 (2) Å	Cell parameters from 3014 reflections
c = 8.9006 (3) Å	θ = 2.4–28.7°
α = 85.927 (1)°	µ = 3.54 mm^−1
β = 74.334 (2)°	T = 273 K
γ = 68.816 (1)°	Block, yellow
V = 587.14 (3) Å^3	0.40 × 0.20 × 0.10 mm

Data collection

Siemens SMART CCD area-detector diffractometer	3014 independent reflections
Radiation source: fine-focus sealed tube	2720 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.018
ω scans	θmax = 28.7°, θmin = 2.4°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −11→11
Tmin = 0.325, Tmax = 0.704	k = −11→11
6007 measured reflections	l = −11→9

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)] = 0.022	H-atom parameters constrained
wR(F^2) = 0.054	w = 1/[σ^2(Fo^2) + (0.0217P)^2 + 0.5168P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max = 0.001
3014 reflections	Δρmax = 0.84 e Å^−3
173 parameters	Δρmin = −0.53 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0031 (5)

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
Ag1	0.07035 (3)	0.18878 (2)	0.94153 (2)	0.03112 (7)
Ag2	0.28240 (3)	0.45723 (2)	0.86663 (2)	0.03751 (8)
S1	0.30795 (8)	0.80639 (7)	0.83821 (7)	0.02769 (13)
O1	0.3774 (3)	0.6877 (3)	0.7081 (3)	0.0680 (8)
O2	0.2782 (4)	0.7169 (4)	0.9820 (4)	0.0780 (9)
O3	0.4309 (3)	0.8861 (3)	0.8432 (3)	0.0570 (7)
O4	0.1358 (3)	0.9262 (2)	0.8268 (3)	0.0419 (5)
O5	0.5196 (3)	0.1639 (3)	0.8348 (3)	0.0444 (5)
H1W	0.4839	0.0839	0.8418	0.067*
H2W	0.5500	0.1697	0.9173	0.067*
O6	0.2345 (4)	0.8173 (3)	0.4422 (3)	0.0604 (6)
H3W	0.2755	0.7989	0.5218	0.091*
H4W	0.3197	0.8088	0.3615	0.091*
N1	0.1473 (3)	0.2654 (3)	0.6831 (2)	0.0276 (4)
N2	0.2176 (3)	0.3877 (2)	0.6554 (2)	0.0256 (4)
N3	0.1374 (3)	0.2687 (2)	0.1496 (2)	0.0264 (4)
N4	0.2034 (3)	0.3934 (2)	0.1233 (2)	0.0258 (4)
C1	0.1206 (4)	0.2018 (3)	0.5682 (3)	0.0283 (5)
H1	0.0779	0.1125	0.5884	0.034*
C2	0.1528 (3)	0.2603 (3)	0.4140 (3)	0.0232 (4)
C3	0.2201 (3)	0.3845 (3)	0.3869 (2)	0.0210 (4)
C4	0.2548 (3)	0.4426 (3)	0.5148 (3)	0.0242 (4)
H4	0.3074	0.5251	0.4975	0.029*
C5	0.1145 (3)	0.2040 (3)	0.2870 (3)	0.0275 (5)
H5	0.0704	0.1156	0.3025	0.033*
C6	0.2440 (3)	0.4481 (3)	0.2353 (3)	0.0246 (4)
H6	0.2916	0.5342	0.2140	0.029*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ag1	0.04510 (12)	0.03571 (11)	0.01835 (10)	−0.02201 (9)	−0.00701 (8)	0.00051 (7)
Ag2	0.06728 (16)	0.03708 (12)	0.02053 (11)	−0.03075 (11)	−0.01571 (9)	0.00535 (7)
S1	0.0303 (3)	0.0251 (3)	0.0298 (3)	−0.0132 (2)	−0.0069 (2)	0.0011 (2)
O1	0.0495 (14)	0.0702 (18)	0.0745 (19)	−0.0075 (12)	−0.0082 (13)	−0.0427 (14)
O2	0.087 (2)	0.090 (2)	0.0684 (19)	−0.0440 (17)	−0.0346 (16)	0.0518 (17)
O3	0.0514 (13)	0.0456 (13)	0.093 (2)	−0.0313 (11)	−0.0302 (13)	0.0052 (12)
O4	0.0390 (11)	0.0334 (10)	0.0556 (13)	−0.0088 (8)	−0.0203 (10)	−0.0053 (9)
O5	0.0535 (12)	0.0426 (11)	0.0416 (12)	−0.0184 (10)	−0.0180 (10)	0.0019 (9)
O6	0.0629 (15)	0.0692 (17)	0.0565 (15)	−0.0333 (13)	−0.0167 (13)	0.0126 (12)
N1	0.0411 (11)	0.0287 (10)	0.0199 (9)	−0.0188 (9)	−0.0108 (8)	0.0046 (7)
N2	0.0352 (10)	0.0254 (9)	0.0211 (9)	−0.0144 (8)	−0.0104 (8)	0.0013 (7)
N3	0.0350 (11)	0.0293 (10)	0.0193 (9)	−0.0159 (8)	−0.0081 (8)	0.0012 (7)
N4	0.0341 (10)	0.0274 (10)	0.0184 (9)	−0.0142 (8)	−0.0068 (8)	0.0023 (7)
C1	0.0423 (13)	0.0285 (11)	0.0208 (11)	−0.0186 (10)	−0.0116 (10)	0.0045 (8)
C2	0.0302 (11)	0.0235 (10)	0.0185 (10)	−0.0116 (9)	−0.0075 (8)	0.0005 (8)
C3	0.0251 (10)	0.0218 (10)	0.0171 (10)	−0.0086 (8)	−0.0068 (8)	0.0002 (7)
C4	0.0312 (11)	0.0257 (11)	0.0202 (10)	−0.0141 (9)	−0.0083 (9)	0.0008 (8)
C5	0.0388 (13)	0.0305 (12)	0.0203 (11)	−0.0197 (10)	−0.0094 (9)	0.0023 (9)
C6	0.0307 (11)	0.0269 (11)	0.0193 (10)	−0.0144 (9)	−0.0062 (9)	0.0016 (8)

Geometric parameters (Å, º)

Ag1—N3^i	2.295 (2)	O6—H3W	0.8500
Ag1—N1	2.335 (2)	O6—H4W	0.8500
Ag1—O4^ii	2.403 (2)	N1—C1	1.304 (3)
Ag1—O2^iii	2.632 (3)	N1—N2	1.379 (3)
Ag1—O4^iii	2.700 (2)	N2—C4	1.307 (3)
Ag1—Ag2	3.3635 (3)	N3—C5	1.307 (3)
Ag2—N2	2.2703 (19)	N3—N4	1.375 (3)
Ag2—N4^i	2.2890 (19)	N4—C6	1.308 (3)
Ag2—O2	2.551 (4)	C1—C2	1.421 (3)
Ag2—O5	2.600 (2)	C1—H1	0.9600
Ag2—O1	2.621 (3)	C2—C3	1.377 (3)
S1—O3	1.449 (2)	C2—C5	1.420 (3)
S1—O1	1.461 (2)	C3—C6	1.415 (3)
S1—O2	1.464 (2)	C3—C4	1.417 (3)
S1—O4	1.471 (2)	C4—H4	0.9600
O5—H1W	0.8500	C5—H5	0.9600
O5—H2W	0.8500	C6—H6	0.9600
N3^i—Ag1—N1	126.39 (7)	Ag2—O5—H1W	117.8
N3^i—Ag1—O4^ii	133.04 (7)	Ag2—O5—H2W	95.3
N1—Ag1—O4^ii	84.30 (8)	H1W—O5—H2W	108.4
N3^i—Ag1—O2^iii	105.18 (9)	H3W—O6—H4W	108.4
N1—Ag1—O2^iii	104.87 (8)	C1—N1—N2	120.0 (2)
O4^ii—Ag1—O2^iii	97.94 (9)	C1—N1—Ag1	122.86 (16)
N3^i—Ag1—O4^iii	81.48 (7)	N2—N1—Ag1	117.06 (14)
N1—Ag1—O4^iii	150.62 (7)	C4—N2—N1	120.26 (19)
O4^ii—Ag1—O4^iii	80.86 (8)	C4—N2—Ag2	125.96 (16)
O2^iii—Ag1—O4^iii	52.93 (7)	N1—N2—Ag2	113.51 (13)
N3^i—Ag1—Ag2	63.80 (5)	C5—N3—N4	120.2 (2)
N1—Ag1—Ag2	62.67 (5)	C5—N3—Ag1^v	123.82 (16)
O4^ii—Ag1—Ag2	132.32 (6)	N4—N3—Ag1^v	115.96 (14)
O2^iii—Ag1—Ag2	122.16 (7)	C6—N4—N3	120.33 (19)
O4^iii—Ag1—Ag2	142.90 (4)	C6—N4—Ag2^v	123.93 (16)
N2—Ag2—N4^i	130.29 (7)	N3—N4—Ag2^v	114.74 (14)
N2—Ag2—O2	136.82 (7)	N1—C1—C2	122.1 (2)
N4^i—Ag2—O2	83.34 (8)	N1—C1—H1	118.9
N2—Ag2—O5	85.30 (7)	C2—C1—H1	118.9
N4^i—Ag2—O5	84.55 (7)	C3—C2—C5	117.6 (2)
O2—Ag2—O5	129.78 (8)	C3—C2—C1	117.8 (2)
N2—Ag2—O1	89.94 (8)	C5—C2—C1	124.6 (2)
N4^i—Ag2—O1	137.17 (8)	C2—C3—C6	117.8 (2)
O2—Ag2—O1	54.11 (8)	C2—C3—C4	117.4 (2)
O5—Ag2—O1	117.25 (7)	C6—C3—C4	124.8 (2)
O3—S1—O1	112.14 (17)	N2—C4—C3	122.3 (2)
O3—S1—O2	109.02 (17)	N2—C4—H4	118.8
O1—S1—O2	107.1 (2)	C3—C4—H4	118.8
O3—S1—O4	111.27 (13)	N3—C5—C2	122.0 (2)
O1—S1—O4	108.93 (14)	N3—C5—H5	119.0
O2—S1—O4	108.18 (16)	C2—C5—H5	119.0
S1—O1—Ag2	96.28 (15)	N4—C6—C3	122.1 (2)
S1—O2—Ag2	99.18 (17)	N4—C6—H6	119.0
S1—O4—Ag1^iv	112.96 (11)	C3—C6—H6	119.0
N3^i—Ag1—Ag2—N2	−179.14 (8)	O2^iii—Ag1—N1—C1	−65.2 (2)
N1—Ag1—Ag2—N2	3.82 (8)	O4^iii—Ag1—N1—C1	−28.3 (3)
O4^ii—Ag1—Ag2—N2	55.37 (9)	Ag2—Ag1—N1—C1	175.9 (2)
O2^iii—Ag1—Ag2—N2	−87.12 (10)	N3^i—Ag1—N1—N2	−9.7 (2)
O4^iii—Ag1—Ag2—N2	−156.68 (9)	O4^ii—Ag1—N1—N2	−150.87 (17)
N3^i—Ag1—Ag2—N4^i	−4.74 (8)	O2^iii—Ag1—N1—N2	112.40 (18)
N1—Ag1—Ag2—N4^i	178.21 (8)	O4^iii—Ag1—N1—N2	149.31 (14)
O4^ii—Ag1—Ag2—N4^i	−130.24 (9)	Ag2—Ag1—N1—N2	−6.46 (14)
O2^iii—Ag1—Ag2—N4^i	87.28 (10)	C1—N1—N2—C4	1.3 (3)
O4^iii—Ag1—Ag2—N4^i	17.71 (9)	Ag1—N1—N2—C4	−176.35 (17)
N3^i—Ag1—Ag2—O2	−43.36 (11)	C1—N1—N2—Ag2	−173.04 (19)
N1—Ag1—Ag2—O2	139.59 (11)	Ag1—N1—N2—Ag2	9.3 (2)
O4^ii—Ag1—Ag2—O2	−168.86 (11)	N4^i—Ag2—N2—C4	173.12 (18)
O2^iii—Ag1—Ag2—O2	48.66 (15)	O2—Ag2—N2—C4	40.2 (3)
O4^iii—Ag1—Ag2—O2	−20.91 (11)	O5—Ag2—N2—C4	−108.1 (2)
N3^i—Ag1—Ag2—O5	87.91 (8)	O1—Ag2—N2—C4	9.3 (2)
N1—Ag1—Ag2—O5	−89.13 (8)	Ag1—Ag2—N2—C4	179.8 (2)
O4^ii—Ag1—Ag2—O5	−37.58 (8)	N4^i—Ag2—N2—N1	−12.9 (2)
O2^iii—Ag1—Ag2—O5	179.93 (9)	O2—Ag2—N2—N1	−145.85 (17)
O4^iii—Ag1—Ag2—O5	110.37 (8)	O5—Ag2—N2—N1	65.87 (16)
N3^i—Ag1—Ag2—O1	−156.75 (13)	O1—Ag2—N2—N1	−176.77 (16)
N1—Ag1—Ag2—O1	26.20 (14)	Ag1—Ag2—N2—N1	−6.27 (14)
O4^ii—Ag1—Ag2—O1	77.75 (14)	C5—N3—N4—C6	0.1 (3)
O2^iii—Ag1—Ag2—O1	−64.73 (14)	Ag1^v—N3—N4—C6	179.44 (17)
O4^iii—Ag1—Ag2—O1	−134.30 (14)	C5—N3—N4—Ag2^v	169.06 (18)
O3—S1—O1—Ag2	136.17 (12)	Ag1^v—N3—N4—Ag2^v	−11.6 (2)
O2—S1—O1—Ag2	16.59 (17)	N2—N1—C1—C2	−3.5 (4)
O4—S1—O1—Ag2	−100.21 (13)	Ag1—N1—C1—C2	174.01 (18)
N2—Ag2—O1—S1	143.13 (13)	N1—C1—C2—C3	2.3 (4)
N4^i—Ag2—O1—S1	−18.70 (19)	N1—C1—C2—C5	−175.3 (2)
O2—Ag2—O1—S1	−11.14 (11)	C5—C2—C3—C6	0.8 (3)
O5—Ag2—O1—S1	−132.19 (11)	C1—C2—C3—C6	−177.0 (2)
Ag1—Ag2—O1—S1	122.76 (11)	C5—C2—C3—C4	178.7 (2)
O3—S1—O2—Ag2	−138.75 (13)	C1—C2—C3—C4	1.0 (3)
O1—S1—O2—Ag2	−17.18 (17)	N1—N2—C4—C3	2.1 (3)
O4—S1—O2—Ag2	100.12 (13)	Ag2—N2—C4—C3	175.69 (16)
N2—Ag2—O2—S1	−28.2 (2)	C2—C3—C4—N2	−3.2 (3)
N4^i—Ag2—O2—S1	−173.97 (16)	C6—C3—C4—N2	174.7 (2)
O5—Ag2—O2—S1	108.84 (14)	N4—N3—C5—C2	1.2 (4)
O1—Ag2—O2—S1	11.20 (12)	Ag1^v—N3—C5—C2	−178.12 (18)
Ag1—Ag2—O2—S1	−139.42 (10)	C3—C2—C5—N3	−1.6 (4)
O3—S1—O4—Ag1^iv	−27.90 (19)	C1—C2—C5—N3	176.0 (2)
O1—S1—O4—Ag1^iv	−152.04 (16)	N3—N4—C6—C3	−0.9 (4)
O2—S1—O4—Ag1^iv	91.82 (18)	Ag2^v—N4—C6—C3	−168.84 (16)
N3^i—Ag1—N1—C1	172.66 (19)	C2—C3—C6—N4	0.5 (4)
O4^ii—Ag1—N1—C1	31.5 (2)	C4—C3—C6—N4	−177.4 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H1W···O3^ii	0.85	1.94	2.785 (3)	173
O5—H2W···O3^vi	0.85	2.19	2.985 (4)	156
O5—H2W···O2^vi	0.85	2.39	3.104 (4)	142
O6—H3W···O1	0.85	2.09	2.914 (4)	164
O6—H4W···O5^vii	0.85	1.96	2.792 (3)	167
C4—H4···O6	0.96	2.46	3.260 (4)	141

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