A host–guest complex of di­aqua­bis­[1-hydroxy-2(1H)-pyridine­thionato-O,S]­magnesium(II) and 2,2′-di­thio­bis­(pyridine N-oxide)

The title compound, [Mg(C₅H₄NOS)₂(H₂O)₂]·C₁₀H₈N₂O₂S₂, is a two-component host–guest material. The 2,2′-di­thio­bis(pyridine N-oxide) molecule has crystallographic twofold symmetry. The metal complex lies on an inversion centre and associates via C—H...S interactions into chains which thread the 2,2′-di­thio­bis­(pyridine N-oxide) lattice in perpendicular directions. Hydro­gen bonds exist between the water mol­ecules of the di­aqua­magnesium units and the N—O groups of the host lattice.

S1. Comment

1-Hydroxy-2(1H)-pyridinethione, pyrithione, has been widely studied as a result of its fungicidal properties (Albert et al., 1956; Chandler & Segal, 1978; Bond & Jones, 1999). Pyrithione is readily oxidized to the disulfide, i.e. 2,2'-dithiobis(pyridine N-oxide) (DTPO), which also displays fungicidal activity (Paulus, 1993). The crystal structure of DTPO consists of a three-dimensional C—H···O-bonded lattice composed of two interpenetrated homochiral networks (Bodige et al., 1997). The DTPO lattice has been shown to be suitable for guest inclusion by the formation of the host–guest complexes [TCNB][DTPO]₂(H₂O)₄ and [PMDA][DTPO]₂, where TCNB and PMDA represent 1,2,4,5-tetracyanobenzene and pyromellitic dianhydride, respectively (Bodige et al., 1997). The title compound, [Mg(C₅H₄NOS)₂(H₂O)₂]^.C₁₀H₈N₂O₂S₂, (I), is a host–guest material in which a diaquamagnesium complex of pyrithione is incorporated into a DTPO lattice.

The Mg atom of the [Mg(C₅H₄NOS)₂(H₂O)₂] unit occupies a centre of symmetry and adopts distorted octahedral coordination via two bidentate pyrithione ligands and two water molecules (Fig. 1). The pyrithione ligands are tilted with respect to the equatorial plane defined by O1, S1, O1ⁱ and S1ⁱ [symmetry code: (i) 0.5 - x, 0.5 - y, -z], forming an angle of 27.5 (1)°. The DTPO molecule is chiral as a result of the fixed C2—S2—S2ⁱⁱ—C2ⁱⁱ torsion angle [symmetry code: (ii) -x, y, 0.5 - z]; both enantiomers are present in the crystal. The magnitude of this torsion angle, 80.3 (1)°, is considerably less than the value of 90.2 (2)° observed in DTPO itself, showing the DTPO lattice to be distorted significantly on incorporation of the [Mg(C₅H₄NOS)₂(H₂O)₂] guest.

The [Mg(C₅H₄NOS)₂(H₂O)₂] units in (I) are linked via C—H···S interactions [C4···S1ⁱⁱⁱ 3.565 (2) Å and C4—H4···S1ⁱⁱⁱ 147.6°; symmetry code: (iii) -0.5 + x, -0.5 + y, z] into chains running parallel to [110] and [110]. The C—H···O network observed in DTPO is disrupted by guest insertion and the dominant interactions in (I) are hydrogen bonds between the water molecules of the diaquamagnesium units and the N—O groups of the DTPO lattice [H100···O2^iv 1.91 (2) Å and O3—H100···O2^iv 174 (2)°; H101···O2^v 2.02 (2) Å and O3—H101···O2^v 160 (2)°; symmetry codes: (iv) 0.5 + x, 0.5 - y, -0.5 + z; (v) 0.5 - x, -0.5 + y, 0.5 - z] (Fig. 2).

The structure of (I) may be related to that of [PMDA][DTPO]₂ in which PMDA molecules associate via C—H···O interactions to yield chains similar to the [Mg(C₅H₄NOS)₂(H₂O)₂]_n chains in (I). These thread the DTPO lattice in one direction giving rise to a solid-state polypseudorotaxane structure. The planar nature of the PMDA chains allows for face-to-face aromatic interactions between the PMDA molecules and the DTPO lattice. In (I), however, the diaquamagnesium unit introduces water molecules above and below the plane of the [Mg(C₅H₄NOS)₂(H₂O)₂]_n chains, facilitating additional hydrogen-bond interactions with the DTPO lattice and giving rise to the new three-dimensional architecture.

S2. Experimental

C₅H₅NOS and Mg(OAc)₂ were dissolved in an EtOH/H₂O mixture with stirring. The solvent was removed by evaporation and the resulting powder was recrystallized from EtOH to yield single crystals of (I).

S3. Refinement

The water H atoms, H100 and H101, were located in a difference Fourier map and refined with a fixed isotropic displacement parameter of 0.05 Ų and a restrained O—H distance of 0.82 (2) Å.

Computing details

Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1998); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997b); molecular graphics: XP in SHELXTL/PC (Sheldrick, 1994) and CAMERON (Pearce et al., 1993); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The molecular units in (I) showing displacement ellipsoids at 50% probability [symmetry codes: (i) -x, y, 0.5 - z; (ii) 0.5 - x, 0.5 - y, -z]. H atoms have been omitted.
	Fig. 2. View of (I) parallel to [110] with the DTPO lattice shaded grey. [Mg(C5H4NOS)2(H2O)2]n chains run vertically and normal to the plane of the page. O—H···O and C—H···S interactions are indicated by dotted lines.

[diaquabis(1-hydroxy-2(1H)-pyridinethiolato)magnesium(II)] [2,2'-dithiobis(pyridine-N-oxide)]

Crystal data

[Mg(C5H4NOS)2(H2O)2]·C10H8N2O2S2	F(000) = 1168
Mr = 564.95	Dx = 1.583 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 8.101 (2) Å	Cell parameters from 25 reflections
b = 13.564 (3) Å	θ = 12.5–15.0°
c = 21.573 (4) Å	µ = 0.47 mm^−1
β = 91.13 (3)°	T = 296 K
V = 2370.1 (8) Å^3	Block, colourless
Z = 4	0.6 × 0.3 × 0.3 mm

Data collection

Rigaku AFC7R four-circle diffractometer	2179 reflections with I > 2σ(I)
Radiation source: rotating anode	Rint = 0.065
Graphite monochromator	θmax = 27.5°, θmin = 2.9°
ω–2θ scans	h = 0→10
Absorption correction: ψ scan (North et al., 1968)	k = 0→17
Tmin = 0.840, Tmax = 0.867	l = −28→28
2910 measured reflections	3 standard reflections every 200 reflections
2721 independent reflections	intensity decay: none

Refinement

Refinement on F^2	2 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.036	w = 1/[σ^2(Fo^2) + (0.0371P)^2 + 1.5439P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.096	(Δ/σ)max = 0.017
S = 1.02	Δρmax = 0.25 e Å^−3
2721 reflections	Δρmin = −0.30 e Å^−3
166 parameters

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.

All H atoms on the aromatic rings were positioned geometrically with C—H distances of 0.93 Å and refined using a riding model with the U_iso values for each H atom taken as 1.2U_eq of the carrier atoms.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Mg1	0.2500	0.2500	0.0000	0.0299 (2)
S1	0.23314 (6)	0.24485 (4)	0.11963 (2)	0.03627 (14)
S2	−0.00484 (7)	0.49278 (4)	0.29740 (3)	0.04457 (15)
O1	0.03055 (17)	0.18163 (11)	0.01296 (6)	0.0417 (4)
O2	0.0750 (2)	0.45559 (13)	0.41489 (7)	0.0595 (5)
O3	0.3774 (2)	0.11631 (12)	0.00599 (8)	0.0535 (4)
H100	0.438 (3)	0.0984 (18)	−0.0224 (10)	0.050*
H101	0.380 (3)	0.0789 (16)	0.0348 (9)	0.050*
N1	0.01097 (19)	0.12713 (11)	0.06377 (7)	0.0319 (3)
N2	0.1532 (2)	0.39038 (14)	0.38050 (8)	0.0427 (4)
C1	0.0965 (2)	0.14896 (13)	0.11756 (8)	0.0296 (4)
C2	0.0642 (3)	0.08833 (16)	0.16857 (10)	0.0411 (5)
H2	0.1199	0.1002	0.2059	0.049*
C3	−0.0462 (3)	0.01244 (16)	0.16508 (11)	0.0488 (5)
H3	−0.0655	−0.0265	0.1997	0.059*
C4	−0.1295 (3)	−0.00609 (16)	0.10948 (11)	0.0486 (6)
H4	−0.2055	−0.0573	0.1063	0.058*
C5	−0.0981 (3)	0.05200 (15)	0.05976 (10)	0.0422 (5)
H5	−0.1529	0.0398	0.0222	0.051*
C6	0.1301 (2)	0.39582 (15)	0.31852 (9)	0.0359 (4)
C7	0.2058 (3)	0.32885 (16)	0.28043 (10)	0.0424 (5)
H7	0.1896	0.3321	0.2377	0.051*
C8	0.3057 (3)	0.25690 (19)	0.30630 (13)	0.0554 (6)
H8	0.3583	0.2116	0.2811	0.066*
C9	0.3273 (3)	0.2526 (2)	0.36959 (14)	0.0621 (7)
H9	0.3941	0.2042	0.3875	0.074*
C10	0.2503 (3)	0.3196 (2)	0.40594 (12)	0.0581 (7)
H10	0.2647	0.3166	0.4488	0.070*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mg1	0.0363 (5)	0.0264 (4)	0.0271 (4)	−0.0043 (4)	0.0031 (3)	0.0027 (3)
S1	0.0434 (3)	0.0366 (3)	0.0288 (2)	−0.0137 (2)	0.00074 (19)	−0.00224 (18)
S2	0.0504 (3)	0.0377 (3)	0.0458 (3)	0.0043 (2)	0.0053 (2)	−0.0092 (2)
O1	0.0452 (8)	0.0500 (8)	0.0295 (7)	−0.0170 (7)	−0.0057 (6)	0.0108 (6)
O2	0.0820 (12)	0.0559 (10)	0.0413 (9)	−0.0246 (9)	0.0167 (8)	−0.0212 (8)
O3	0.0789 (12)	0.0392 (9)	0.0433 (9)	0.0184 (8)	0.0220 (8)	0.0140 (7)
N1	0.0341 (8)	0.0314 (8)	0.0303 (8)	−0.0070 (6)	0.0028 (6)	0.0012 (6)
N2	0.0458 (10)	0.0493 (10)	0.0330 (9)	−0.0173 (8)	0.0016 (7)	−0.0086 (8)
C1	0.0316 (9)	0.0285 (9)	0.0288 (9)	−0.0002 (7)	0.0031 (7)	−0.0001 (7)
C2	0.0448 (11)	0.0449 (11)	0.0336 (10)	−0.0058 (9)	0.0009 (8)	0.0075 (9)
C3	0.0582 (14)	0.0429 (12)	0.0455 (12)	−0.0110 (10)	0.0077 (10)	0.0133 (10)
C4	0.0584 (14)	0.0353 (11)	0.0527 (13)	−0.0199 (10)	0.0126 (11)	−0.0025 (9)
C5	0.0458 (11)	0.0418 (11)	0.0392 (11)	−0.0171 (9)	0.0029 (9)	−0.0061 (9)
C6	0.0343 (10)	0.0401 (10)	0.0334 (9)	−0.0071 (8)	0.0009 (8)	−0.0055 (8)
C7	0.0418 (11)	0.0466 (12)	0.0389 (11)	0.0031 (9)	0.0021 (8)	−0.0038 (9)
C8	0.0411 (12)	0.0572 (14)	0.0680 (16)	0.0075 (11)	0.0050 (11)	0.0049 (12)
C9	0.0403 (12)	0.0689 (17)	0.0765 (18)	0.0001 (12)	−0.0105 (12)	0.0191 (14)
C10	0.0572 (15)	0.0729 (17)	0.0437 (13)	−0.0210 (13)	−0.0164 (11)	0.0122 (12)

Geometric parameters (Å, º)

Mg1—O1	2.0294 (14)	C1—C2	1.403 (3)
Mg1—O1^i	2.0294 (14)	C2—C3	1.365 (3)
Mg1—O3	2.0895 (16)	C2—H2	0.9300
Mg1—O3^i	2.0895 (16)	C3—C4	1.388 (3)
Mg1—S1^i	2.5881 (7)	C3—H3	0.9300
Mg1—S1	2.5881 (7)	C4—C5	1.359 (3)
S1—C1	1.7080 (18)	C4—H4	0.9300
S2—C6	1.764 (2)	C5—H5	0.9300
S2—S2^ii	2.0480 (12)	C6—C7	1.377 (3)
O1—N1	1.3341 (19)	C7—C8	1.379 (3)
O2—N2	1.324 (2)	C7—H7	0.9300
O3—H100	0.827 (16)	C8—C9	1.374 (4)
O3—H101	0.801 (16)	C8—H8	0.9300
N1—C5	1.351 (2)	C9—C10	1.359 (4)
N1—C1	1.372 (2)	C9—H9	0.9300
N2—C6	1.349 (3)	C10—H10	0.9300
N2—C10	1.351 (3)
O1—Mg1—O1^i	180.00 (10)	C2—C1—S1	123.83 (15)
O1—Mg1—O3	91.60 (7)	C3—C2—C1	122.1 (2)
O1^i—Mg1—O3	88.40 (7)	C3—C2—H2	119.0
O1—Mg1—O3^i	88.40 (7)	C1—C2—H2	119.0
O1^i—Mg1—O3^i	91.60 (7)	C2—C3—C4	119.4 (2)
O3—Mg1—O3^i	180.00 (14)	C2—C3—H3	120.3
O1—Mg1—S1^i	102.32 (5)	C4—C3—H3	120.3
O1^i—Mg1—S1^i	77.68 (5)	C5—C4—C3	118.8 (2)
O3—Mg1—S1^i	92.83 (5)	C5—C4—H4	120.6
O3^i—Mg1—S1^i	87.17 (5)	C3—C4—H4	120.6
O1—Mg1—S1	77.68 (5)	N1—C5—C4	121.3 (2)
O1^i—Mg1—S1	102.32 (5)	N1—C5—H5	119.4
O3—Mg1—S1	87.17 (5)	C4—C5—H5	119.4
O3^i—Mg1—S1	92.83 (5)	N2—C6—C7	120.0 (2)
S1^i—Mg1—S1	180.00 (3)	N2—C6—S2	111.73 (15)
C1—S1—Mg1	92.37 (6)	C7—C6—S2	128.21 (16)
C6—S2—S2^ii	102.84 (7)	C6—C7—C8	119.4 (2)
N1—O1—Mg1	119.02 (11)	C6—C7—H7	120.3
Mg1—O3—H100	120.5 (17)	C8—C7—H7	120.3
Mg1—O3—H101	127.0 (18)	C9—C8—C7	119.6 (2)
H100—O3—H101	112 (2)	C9—C8—H8	120.2
O1—N1—C5	116.99 (16)	C7—C8—H8	120.2
O1—N1—C1	120.60 (14)	C10—C9—C8	119.6 (2)
C5—N1—C1	122.40 (16)	C10—C9—H9	120.2
O2—N2—C6	117.39 (19)	C8—C9—H9	120.2
O2—N2—C10	121.9 (2)	N2—C10—C9	120.7 (2)
C6—N2—C10	120.7 (2)	N2—C10—H10	119.6
N1—C1—C2	115.99 (17)	C9—C10—H10	119.6
N1—C1—S1	120.18 (13)
O1—Mg1—S1—C1	22.07 (8)	S1—C1—C2—C3	179.87 (17)
O1^i—Mg1—S1—C1	−157.93 (8)	C1—C2—C3—C4	0.2 (4)
O3—Mg1—S1—C1	−70.19 (8)	C2—C3—C4—C5	0.2 (4)
O3^i—Mg1—S1—C1	109.81 (8)	O1—N1—C5—C4	−178.4 (2)
S1^i—Mg1—S1—C1	68 (100)	C1—N1—C5—C4	0.3 (3)
O1^i—Mg1—O1—N1	−170 (62)	C3—C4—C5—N1	−0.5 (4)
O3—Mg1—O1—N1	56.80 (14)	O2—N2—C6—C7	−178.80 (18)
O3^i—Mg1—O1—N1	−123.20 (14)	C10—N2—C6—C7	0.0 (3)
S1^i—Mg1—O1—N1	150.04 (12)	O2—N2—C6—S2	0.0 (2)
S1—Mg1—O1—N1	−29.96 (12)	C10—N2—C6—S2	178.76 (16)
Mg1—O1—N1—C5	−152.28 (14)	S2^ii—S2—C6—N2	173.81 (13)
Mg1—O1—N1—C1	29.0 (2)	S2^ii—S2—C6—C7	−7.5 (2)
O1—N1—C1—C2	178.71 (17)	N2—C6—C7—C8	−0.3 (3)
C5—N1—C1—C2	0.1 (3)	S2—C6—C7—C8	−178.94 (17)
O1—N1—C1—S1	−1.5 (2)	C6—C7—C8—C9	0.5 (4)
C5—N1—C1—S1	179.89 (15)	C7—C8—C9—C10	−0.3 (4)
Mg1—S1—C1—N1	−17.75 (15)	O2—N2—C10—C9	179.0 (2)
Mg1—S1—C1—C2	162.04 (17)	C6—N2—C10—C9	0.3 (3)
N1—C1—C2—C3	−0.3 (3)	C8—C9—C10—N2	−0.1 (4)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4···S1^iii	0.93	2.74	3.565 (2)	148
O3—H100···O2^iv	0.83 (2)	1.91 (2)	2.739 (2)	174 (2)
O3—H101···O2^v	0.80 (2)	2.02 (2)	2.791 (2)	160 (2)

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