Poly[[[tri(urea-κO)manganese(II)]-μ-thiocyanato-κ²N:S-mercury(II)]-tri-μ-tetrathiocyanato]

The title complex, [MnHg(SCN)₄(CH₄N₂O)₃]_n, consists of slightly distorted octahedral MnN₃O₃ and tetrahedral HgS₄ units. The Mn^II atom is coordinated by the O atoms of three urea mol­ecules and by the N atoms of three SCN⁻ ions; Hg^II is coordinated by four S atoms from SCN⁻ ions. Each pair of Mn^II and Hg^II atoms is connected by an –SCN– bridge, forming infinite two-dimensional –Mn—NCS—Hg– networks.

S1. Comment

Owing to the diverse applications of coordination compounds in chemistry-physics and technology, there exists continuing interest in the synthesis and characterization of compounds especially those of transition metals. In these studies, supramolecular architecture of multi-dimensional networks is one of the most attractive field from the technological point of view because these networks may have electronic, magnetic, optical or catalytic applications (Batten & Robson, 1998). For designing infinite inorganic and organic frameworks, various pseudohalide and pseudochalocogenide ions, such as CN^-, OCN^-, SCN^-, SeCN^-, CNO^-, N₃^-, CN₂^2-, SN₂^2- and complementary ligands are used (Kitazawa et al., 1994; Cortes et al., 1997; Munno et al., 1997; Wang et al., 2000; Nandibewoor et al., 2000; Thirumaran & Ramalingam, 2000; Becker & Jansen, 2001). Due to their versatility in acting as monodentate, bidentate or bridging ligands, multi-dimensional framework structures linking alternately one metal atom M to another M' could be built by using pseudohalide or pseudochalocogenide ions.

Coordination chemistries of transition metals have been extensively studied from a chemical and structural point of view, mainly due to the capability of theirs to adopt different modes of coordination determined by considerations of size, as well as electrostatic and covalent bonding forces. The presence of pseudohalide and pseudochalocogenide ions introduces some additional degrees of freedom.

As a part of these investigations, the title compound (I), the urea adduct of manganese mercury thiocyanate, MnHg(SCN)₄ (Yan et al., 1999) has been prepared, which has been introduced SCN^-ions as bridging ligands [linking manganese(II) and mercury(II)] and urea as complementary ligands.

According to the hard and soft acid and bases (HSAB) concept (Pearson, 1966; Balarew & Duhlew, 1984), the harder metals show a pronounced affinity for coordination with harder ligands while softer metals prefer coordination with softer ligands. In this structure, each harder Mn^II is hexa-coordinated via harder 3 N(SCN)3O(urea) and in a slightly distorted octahedral geometry; and each softer Hg^II is tetracoordinated via softer 4S(SCN) and in a slightly distorted tetragonal geometry.

Each Mn^II is bound to three N atoms belonging to SCN groups and three O atoms to urea ligands. The resulting of hexa-coordinated Mn^II surrounding exhibits slight distortions from the ideal octahedron. The bond lengths of Mn—N [range 2.225 (5)–2.243 (5) Å] and those of Mn—O [range 2.152 (3)–2.197 (4) Å] are both much longer than the sum of Shannon's ionic radii, 2.13 and 2.02 Å (Shannon, 1976), respectively. This is probably because the assumed valences of the N and O atoms are not appropriated, for the charges on the SCN^- ions and urea molecules are much delocalized. The bond angles for N—Mn—N, O—Mn—N and O—Mn—O (between adjacent atoms) range 87.2 (2)–88.7 (2), 88.2 (2)–94.8 (2) and 86.18 (14)–91.71 (13)° with the average values 87.95, 90.82 and 88.95°, respectively, which are somewhat different from the typical octahedral angles, 90°.

Each Hg^II, coordinated with four SCN S atoms, is in tetrahedral geometry. The tetrahedron is also slightly deformed. The Hg—S bond lengths are in the range 2.4865 (14)–2.6035 (15) Å, on the average 2.5473 Å, are much shorter than the sum of the Shannon ionic radii, 2.80 Å (Shannon, 1976), which all the more exhibits considerable delocaization of the charges on the SCN^- ions. The bond angles for S—Hg—S [range 101.84 (5)–126.91 (6)°] are distinctly deviated from the typical tetrahedral angle.

Among the C—S—Hg angles, the bond angle of C1—S1—Hg1 is much larger than that of the rest. Although the bond angles of C2—N2—Mn1 [172.0 (4)°] and C3—N3—Mn1 [178.2 (4)°] are both close to 180.0°, however, that of C1—N1—Mn1 [159.1 (4)°] is obviously smaller and exhibit a significant bending. The SCN groups are quasi-linear [the N—C—S angles range 175.9 (5)–178.4 (5)°], which is the striking feature of these kinds of complexes: the –SCN– bridges, which connect bimetals forming infinite two- or three-dimensional networks (three-dimensional networks formed in this complex).

S2. Experimental

MnHg(SCN)₄ was prepared by the reaction of MnX₂, HgX₂ (where X = Cl, NO₃ or CH₃COO) and ASCN (where A = K, Na, or NH₄) (molar ratio 1:1:4) in water. The crystalline powders of MnHg(SCN)₄ and urea were dissolved into water according to the stoichiometric proportion. The mixture was then left standing for several days, thereby crystals of (I) were obtained.

S3. Refinement

The N7 and N8 atoms were disordered. The N7, N7', N8 and N8' atoms were refined isotropically, and their site-occupation factors were 0.59, 0.41, 0.69 and 0.31, respectively. The positions of all H atoms were placed geometrically (N—H = 0.86 Å) and refined using a riding model, with U_iso=1.2U_eq(parent atom).

Computing details

Data collection: XSCANS (Bruker, 1996); cell refinement: XSCANS (Bruker, 1996); data reduction: XSCANS (Bruker, 1996); program(s) used to solve structure: SHELXTL (Bruker, 1997); program(s) used to refine structure: SHELXL93 (Sheldrick, 1993); molecular graphics: SHELXTL (Bruker, 1997).

Figures

	Fig. 1. The molecular structure of (I) showing 50% probability displacement ellipsoids. The hydrogen atoms are omitted for clarity.
	Fig. 2. Packing diagram for (I) showing the three-dimensional network.

(I)

Crystal data

C7H12HgMnN10O3S4	Z = 2
Mr = 668.04	F(000) = 634
Triclinic, P1	Dx = 2.191 Mg m^−3
a = 7.5210 (7) Å	Mo Kα radiation, λ = 0.71073 Å
b = 10.6669 (9) Å	Cell parameters from 53 reflections
c = 13.3202 (9) Å	θ = 4.7–14.5°
α = 80.185 (6)°	µ = 8.64 mm^−1
β = 82.009 (7)°	T = 293 K
γ = 75.147 (7)°	Prism, pale green
V = 1012.69 (14) Å^3	0.31 × 0.21 × 0.20 mm

Data collection

Bruker P4 diffractometer	3229 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.017
Graphite monochromator	θmax = 25.0°, θmin = 2.0°
θ/2θ scans	h = −8→1
Absorption correction: ψ scan XSCANS (Bruker,1996)	k = −12→12
Tmin = 0.125, Tmax = 0.179	l = −15→15
4448 measured reflections	3 standard reflections every 97 reflections
3561 independent reflections	intensity decay: none

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)] = 0.027	H-atom parameters constrained
wR(F^2) = 0.065	w = 1/[σ^2(Fo^2) + (0.0255P)^2 + 2.0461P] where P = (Fo^2 + 2Fc^2)/3
S = 1.02	(Δ/σ)max = −0.002
3558 reflections	Δρmax = 0.84 e Å^−3
236 parameters	Δρmin = −0.81 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0064 (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.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Hg1	0.11801 (3)	0.83307 (2)	0.33629 (2)	0.05191 (11)
Mn1	−0.25073 (10)	0.40068 (7)	0.25381 (5)	0.0377 (2)
S1	0.1281 (2)	0.60520 (15)	0.42110 (13)	0.0633 (4)
S2	0.2927 (3)	0.8242 (2)	0.15528 (14)	0.0843 (6)
S3	0.2131 (3)	1.00831 (15)	0.4057 (2)	0.0757 (5)
S4	−0.2341 (2)	0.92646 (14)	0.32078 (12)	0.0537 (3)
C1	0.0023 (7)	0.5626 (5)	0.3463 (4)	0.0426 (11)
C2	−0.5556 (8)	0.6837 (6)	0.1825 (4)	0.0477 (12)
C3	0.0579 (7)	0.1353 (5)	0.3532 (4)	0.0466 (12)
C4	−0.2257 (8)	0.9276 (5)	0.1956 (5)	0.0546 (14)
C5	−0.0190 (7)	0.3072 (5)	0.0498 (4)	0.0415 (11)
C6	−0.5371 (8)	0.2842 (6)	0.1620 (5)	0.063 (2)
C7	−0.4855 (6)	0.3153 (5)	0.4589 (4)	0.0377 (10)
N1	−0.0825 (6)	0.5254 (4)	0.2972 (3)	0.0487 (10)
N2	−0.4482 (7)	0.5861 (5)	0.1990 (4)	0.0545 (11)
N3	−0.0486 (7)	0.2241 (4)	0.3189 (4)	0.0503 (11)
N4	−0.2178 (9)	0.9340 (6)	0.1084 (5)	0.077 (2)
N5	0.0874 (8)	0.3334 (5)	−0.0354 (4)	0.0654 (15)
H5A	0.1088 (8)	0.4101 (5)	−0.0522 (4)	0.078*
H5B	0.1350 (8)	0.2737 (5)	−0.0739 (4)	0.078*
N6	−0.0369 (8)	0.1857 (4)	0.0764 (4)	0.0616 (14)
H6A	−0.0975 (8)	0.1643 (4)	0.1337 (4)	0.074*
H6B	0.0120 (8)	0.1279 (4)	0.0365 (4)	0.074*
N9	−0.5002 (8)	0.2071 (5)	0.4287 (4)	0.0602 (13)
H9A	−0.4580 (8)	0.1910 (5)	0.3677 (4)	0.072*
H9B	−0.5521 (8)	0.1527 (5)	0.4701 (4)	0.072*
N10	−0.5469 (6)	0.3337 (4)	0.5555 (3)	0.0498 (11)
H10A	−0.5354 (6)	0.4017 (4)	0.5781 (3)	0.060*
H10B	−0.5980 (6)	0.2775 (4)	0.5951 (3)	0.060*
O1	−0.0878 (5)	0.3948 (3)	0.1055 (3)	0.0483 (9)
O2	−0.3973 (5)	0.2729 (4)	0.2029 (3)	0.0511 (9)
O3	−0.4110 (5)	0.3965 (3)	0.4008 (3)	0.0462 (8)
N7	−0.5441 (17)	0.2077 (11)	0.0933 (12)	0.066 (4)*	0.59 (3)
H7A	−0.4480 (17)	0.1484 (11)	0.0768 (12)	0.079*	0.59 (3)
H7B	−0.6446 (17)	0.2180 (11)	0.0657 (12)	0.079*	0.59 (3)
N8	−0.6875 (12)	0.3780 (8)	0.1862 (6)	0.069 (3)*	0.69 (2)
H8A	−0.6836 (12)	0.4282 (8)	0.2296 (6)	0.083*	0.69 (2)
H8B	−0.7875 (12)	0.3877 (8)	0.1583 (6)	0.083*	0.69 (2)
N7'	−0.5834 (19)	0.1797 (14)	0.1369 (14)	0.052 (4)*	0.41 (3)
H7'A	−0.5134 (19)	0.1025 (14)	0.1497 (14)	0.062*	0.41 (3)
H7'B	−0.6829 (19)	0.1906 (14)	0.1082 (14)	0.062*	0.41 (3)
N8'	−0.616 (4)	0.409 (3)	0.100 (3)	0.135 (13)*	0.31 (2)
H8'A	−0.563 (4)	0.474 (3)	0.092 (3)	0.162*	0.31 (2)
H8'B	−0.715 (4)	0.418 (3)	0.071 (3)	0.162*	0.31 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Hg1	0.04664 (14)	0.03664 (13)	0.0745 (2)	−0.01145 (9)	−0.00442 (10)	−0.01239 (9)
Mn1	0.0394 (4)	0.0344 (4)	0.0385 (4)	−0.0095 (3)	0.0019 (3)	−0.0069 (3)
S1	0.0744 (10)	0.0502 (8)	0.0743 (10)	−0.0304 (8)	−0.0330 (8)	0.0108 (7)
S2	0.0779 (12)	0.0730 (11)	0.0658 (10)	0.0234 (9)	0.0074 (9)	0.0145 (8)
S3	0.0701 (10)	0.0381 (7)	0.129 (2)	−0.0079 (7)	−0.0553 (11)	−0.0108 (8)
S4	0.0410 (7)	0.0533 (8)	0.0657 (9)	−0.0089 (6)	0.0015 (6)	−0.0142 (7)
C1	0.041 (3)	0.030 (2)	0.055 (3)	−0.010 (2)	0.001 (2)	−0.002 (2)
C2	0.046 (3)	0.054 (3)	0.040 (3)	−0.010 (3)	0.003 (2)	−0.006 (2)
C3	0.045 (3)	0.039 (3)	0.060 (3)	−0.012 (2)	−0.009 (2)	−0.012 (2)
C4	0.047 (3)	0.036 (3)	0.080 (4)	−0.004 (2)	−0.002 (3)	−0.019 (3)
C5	0.045 (3)	0.039 (3)	0.042 (3)	−0.012 (2)	0.000 (2)	−0.008 (2)
C6	0.048 (3)	0.056 (4)	0.089 (5)	−0.004 (3)	−0.018 (3)	−0.026 (3)
C7	0.035 (2)	0.036 (2)	0.043 (3)	−0.009 (2)	0.001 (2)	−0.007 (2)
N1	0.050 (3)	0.043 (2)	0.056 (3)	−0.015 (2)	−0.002 (2)	−0.011 (2)
N2	0.051 (3)	0.050 (3)	0.055 (3)	−0.002 (2)	0.003 (2)	−0.010 (2)
N3	0.054 (3)	0.037 (2)	0.059 (3)	−0.008 (2)	−0.011 (2)	−0.005 (2)
N4	0.086 (4)	0.061 (3)	0.079 (4)	0.002 (3)	−0.007 (3)	−0.026 (3)
N5	0.097 (4)	0.044 (3)	0.053 (3)	−0.022 (3)	0.026 (3)	−0.018 (2)
N6	0.087 (4)	0.041 (2)	0.056 (3)	−0.023 (2)	0.021 (3)	−0.017 (2)
N9	0.091 (4)	0.049 (3)	0.050 (3)	−0.037 (3)	0.007 (3)	−0.010 (2)
N10	0.064 (3)	0.043 (2)	0.045 (2)	−0.024 (2)	0.013 (2)	−0.010 (2)
O1	0.062 (2)	0.039 (2)	0.043 (2)	−0.017 (2)	0.012 (2)	−0.0108 (15)
O2	0.049 (2)	0.053 (2)	0.058 (2)	−0.017 (2)	−0.009 (2)	−0.014 (2)
O3	0.057 (2)	0.038 (2)	0.045 (2)	−0.019 (2)	0.009 (2)	−0.0090 (15)

Geometric parameters (Å, º)

Hg1—S1	2.4865 (14)	C6—N7	1.341 (12)
Hg1—S3	2.514 (2)	C6—N8	1.346 (10)
Hg1—S2	2.585 (2)	C6—N7'	1.354 (14)
Hg1—S4	2.6035 (15)	C6—N8'	1.48 (3)
Mn1—O3	2.152 (3)	C7—O3	1.250 (6)
Mn1—O1	2.176 (3)	C7—N9	1.320 (6)
Mn1—O2	2.197 (4)	C7—N10	1.335 (6)
Mn1—N3	2.225 (5)	N5—H5A	0.86
Mn1—N2	2.226 (5)	N5—H5B	0.86
Mn1—N1	2.243 (5)	N6—H6A	0.86
S1—C1	1.653 (6)	N6—H6B	0.86
S2—C2^i	1.653 (6)	N9—H9A	0.86
S3—C3^ii	1.667 (6)	N9—H9B	0.86
S4—C4	1.658 (7)	N10—H10A	0.86
C1—N1	1.152 (7)	N10—H10B	0.86
C2—N2	1.151 (7)	N7—H7A	0.86
C2—S2^iii	1.653 (6)	N7—H7B	0.86
C3—N3	1.146 (7)	N8—H8A	0.86
C3—S3^iv	1.667 (6)	N8—H8B	0.86
C4—N4	1.146 (8)	N7'—H7'A	0.86
C5—O1	1.254 (6)	N7'—H7'B	0.86
C5—N6	1.321 (6)	N8'—H8'A	0.86
C5—N5	1.327 (7)	N8'—H8'B	0.86
C6—O2	1.220 (7)
S1—Hg1—S3	126.91 (6)	O2—C6—N8'	119.5 (14)
S1—Hg1—S2	108.63 (6)	N7'—C6—N8'	113.6 (15)
S3—Hg1—S2	105.24 (8)	O3—C7—N9	121.7 (4)
S1—Hg1—S4	101.84 (5)	O3—C7—N10	120.4 (4)
S3—Hg1—S4	103.95 (5)	N9—C7—N10	117.8 (4)
S2—Hg1—S4	109.38 (6)	C1—N1—Mn1	159.1 (4)
O3—Mn1—O1	177.20 (13)	C2—N2—Mn1	172.0 (4)
O3—Mn1—O2	91.71 (13)	C3—N3—Mn1	178.2 (4)
O1—Mn1—O2	86.18 (14)	C5—N5—H5A	120.0 (3)
O3—Mn1—N3	88.2 (2)	C5—N5—H5B	120.0 (3)
O1—Mn1—N3	89.9 (2)	H5A—N5—H5B	120.0
O2—Mn1—N3	89.5 (2)	C5—N6—H6A	120.0 (3)
O3—Mn1—N2	89.3 (2)	C5—N6—H6B	120.0 (3)
O1—Mn1—N2	92.8 (2)	H6A—N6—H6B	120.0
O2—Mn1—N2	94.8 (2)	C7—N9—H9A	120.0 (3)
N3—Mn1—N2	175.1 (2)	C7—N9—H9B	120.0 (3)
O3—Mn1—N1	92.27 (15)	H9A—N9—H9B	120.0
O1—Mn1—N1	89.8 (2)	C7—N10—H10A	120.0 (3)
O2—Mn1—N1	175.6 (2)	C7—N10—H10B	120.0 (3)
N3—Mn1—N1	88.7 (2)	H10A—N10—H10B	120.0
N2—Mn1—N1	87.2 (2)	C5—O1—Mn1	134.5 (3)
C1—S1—Hg1	99.2 (2)	C6—O2—Mn1	138.0 (4)
C2^i—S2—Hg1	97.1 (2)	C7—O3—Mn1	135.7 (3)
C3^ii—S3—Hg1	97.0 (2)	C6—N7—H7A	120.0 (5)
C4—S4—Hg1	97.0 (2)	C6—N7—H7B	120.0 (5)
N1—C1—S1	175.9 (5)	H7A—N7—H7B	120.0
N2—C2—S2^iii	178.3 (5)	C6—N8—H8A	120.0 (4)
N3—C3—S3^iv	178.4 (5)	C6—N8—H8B	120.0 (5)
N4—C4—S4	176.7 (6)	H8A—N8—H8B	120.0
O1—C5—N6	122.3 (5)	C6—N7'—H7'A	120.0 (6)
O1—C5—N5	119.6 (5)	C6—N7'—H7'B	120.0 (6)
N6—C5—N5	117.9 (5)	H7'A—N7'—H7'B	120.0
O2—C6—N7	122.0 (7)	C6—N8'—H8'A	120.0 (13)
O2—C6—N8	118.5 (6)	C6—N8'—H8'B	120.0 (13)
N7—C6—N8	119.5 (7)	H8'A—N8'—H8'B	120.0
O2—C6—N7'	122.0 (7)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N10—H10A···O3^v	0.86	2.15	2.964 (5)	159

Symmetry code: (v) −x−1, −y+1, −z+1.