The title complex, [MnHg(NCS)4(C2H5NO)2]n, consists of slightly distorted MnN4O2 octahedra and HgS4 tetrahedra. Each MnII cation is bound to four N atoms of the NCS groups and two O atoms of the N-methylformamide (NMF) ligands in a cis configuration. Each HgII cation is coordinated to four S atoms of NCS groups. Each pair of MnII and HgII cations is connected by an –NCS– bridge, forming an infinite three-dimensional –Mn—NCS—Hg– network.
Supporting information
CCDC reference: 275498
An NMF solution (5 ml) of MMTC (4.41 g, 9 mmol) was added slowly to water (25 ml) with stirring at room temperature. After a while, compound (I) was precipitated. The crystals used for the X-ray structure analysis were obtained from a mixed solvent of NMF and water (1:3, v/v) using a temperature-lowering method.
All H atoms were placed in calculated positions, with C—H distances of 0.93 or 0.96 Å and N—H distances of 0.86 Å [Please check added text], and refined using a riding model, with Uiso(H) values of 1.2Ueq(C,N), or 1.5Ueq(C) for CH3 groups.
Data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS; data reduction: SHELXTL (Bruker, 1997); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: Please provide missing details.
Poly[(µ-thiocyanato-1:2
κ2S:
N)bis(thiocyanato-2
κN)bis(
N-methylformamide- 2
κO)manganese(II)mercury(II)]
top
Crystal data top
[MnHg(C2H5NO)2(SCN)4] | Dx = 2.121 Mg m−3 |
Mr = 605.99 | Mo Kα radiation, λ = 0.71069 Å |
Orthorhombic, Pna21 | Cell parameters from 43 reflections |
a = 16.1203 (15) Å | θ = 6.4–12.5° |
b = 7.7373 (7) Å | µ = 9.20 mm−1 |
c = 15.2135 (18) Å | T = 293 K |
V = 1897.5 (3) Å3 | Prism, colourless |
Z = 4 | 0.23 × 0.18 × 0.13 mm |
F(000) = 1140 | |
Data collection top
Bruker P4 diffractometer | 1656 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.030 |
Graphite monochromator | θmax = 27.5°, θmin = 2.5° |
ω scans | h = −1→20 |
Absorption correction: ψ scan (XSCANS; Siemens, 1996) | k = −1→10 |
Tmin = 0.10, Tmax = 0.30 | l = −19→1 |
2951 measured reflections | 3 standard reflections every 97 reflections |
2417 independent reflections | intensity decay: none |
Refinement top
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.040 | w = 1/[σ2(Fo2) + (0.0304P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.077 | (Δ/σ)max = 0.001 |
S = 0.98 | Δρmax = 0.68 e Å−3 |
2417 reflections | Δρmin = −0.56 e Å−3 |
203 parameters | Extinction correction: SHELXTL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
1 restraint | Extinction coefficient: 0.00286 (17) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), 162 Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: 0.12 (2) |
Crystal data top
[MnHg(C2H5NO)2(SCN)4] | V = 1897.5 (3) Å3 |
Mr = 605.99 | Z = 4 |
Orthorhombic, Pna21 | Mo Kα radiation |
a = 16.1203 (15) Å | µ = 9.20 mm−1 |
b = 7.7373 (7) Å | T = 293 K |
c = 15.2135 (18) Å | 0.23 × 0.18 × 0.13 mm |
Data collection top
Bruker P4 diffractometer | 1656 reflections with I > 2σ(I) |
Absorption correction: ψ scan (XSCANS; Siemens, 1996) | Rint = 0.030 |
Tmin = 0.10, Tmax = 0.30 | 3 standard reflections every 97 reflections |
2951 measured reflections | intensity decay: none |
2417 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.040 | H-atom parameters constrained |
wR(F2) = 0.077 | Δρmax = 0.68 e Å−3 |
S = 0.98 | Δρmin = −0.56 e Å−3 |
2417 reflections | Absolute structure: Flack (1983), 162 Friedel pairs |
203 parameters | Absolute structure parameter: 0.12 (2) |
1 restraint | |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
C1 | 0.7531 (8) | 0.3591 (16) | 0.6134 (9) | 0.063 (4) | |
C2 | 0.9972 (7) | 0.1733 (16) | 0.4615 (9) | 0.053 (3) | |
C3 | 0.9924 (8) | 0.6752 (18) | 0.6124 (10) | 0.063 (4) | |
C4 | 0.9914 (7) | 0.6918 (18) | 0.2928 (8) | 0.054 (3) | |
C5 | 0.8091 (10) | 0.893 (2) | 0.4438 (12) | 0.073 (4) | |
H5A | 0.8643 | 0.9196 | 0.4325 | 0.088* | |
C6 | 0.6709 (13) | 0.989 (2) | 0.466 (2) | 0.142 (10) | |
H6A | 0.6374 | 1.0731 | 0.4363 | 0.214* | |
H6B | 0.6608 | 0.9965 | 0.5284 | 0.214* | |
H6C | 0.6568 | 0.8754 | 0.4458 | 0.214* | |
C7 | 0.7269 (10) | 0.457 (2) | 0.3243 (12) | 0.061 (4) | |
H7 | 0.7099 | 0.5657 | 0.3439 | 0.074* | |
C8 | 0.7017 (12) | 0.229 (3) | 0.2256 (15) | 0.161 (11) | |
H8A | 0.7024 | 0.2442 | 0.1630 | 0.242* | |
H8B | 0.6615 | 0.1426 | 0.2409 | 0.242* | |
H8C | 0.7556 | 0.1935 | 0.2453 | 0.242* | |
N1 | 0.7936 (7) | 0.3996 (14) | 0.5555 (8) | 0.065 (3) | |
N2 | 0.9499 (7) | 0.2800 (16) | 0.4477 (9) | 0.072 (3) | |
N3 | 0.9536 (7) | 0.6263 (16) | 0.5552 (9) | 0.074 (3) | |
N4 | 0.9507 (7) | 0.6468 (16) | 0.3485 (7) | 0.062 (3) | |
N5 | 0.7558 (11) | 1.0222 (17) | 0.4492 (16) | 0.101 (5) | |
H5B | 0.7727 | 1.1267 | 0.4422 | 0.121* | |
N6 | 0.6807 (7) | 0.3838 (18) | 0.2655 (9) | 0.082 (4) | |
H6D | 0.6351 | 0.4332 | 0.2505 | 0.098* | |
O1 | 0.7911 (5) | 0.7407 (12) | 0.4526 (8) | 0.071 (3) | |
O2 | 0.7906 (6) | 0.3990 (12) | 0.3568 (6) | 0.063 (3) | |
S1 | 0.6957 (2) | 0.2982 (6) | 0.6976 (3) | 0.0829 (12) | |
Mn1 | 0.87366 (12) | 0.5179 (2) | 0.45198 (15) | 0.0525 (5) | |
Hg1 | 0.56627 (3) | 0.45301 (6) | 0.64685 (5) | 0.06246 (18) | |
S2 | 1.0660 (3) | 0.0241 (5) | 0.4798 (3) | 0.0734 (11) | |
S3 | 1.0456 (3) | 0.7393 (6) | 0.6995 (3) | 0.0876 (13) | |
S4 | 1.0481 (2) | 0.7590 (5) | 0.2100 (3) | 0.0665 (10) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.057 (7) | 0.050 (7) | 0.081 (11) | −0.003 (6) | −0.007 (7) | 0.019 (8) |
C2 | 0.057 (7) | 0.050 (7) | 0.052 (7) | 0.002 (7) | 0.008 (7) | −0.007 (7) |
C3 | 0.058 (7) | 0.059 (8) | 0.072 (11) | 0.005 (7) | 0.001 (7) | 0.012 (8) |
C4 | 0.049 (7) | 0.072 (10) | 0.040 (7) | 0.014 (7) | −0.001 (6) | 0.004 (7) |
C5 | 0.069 (10) | 0.065 (10) | 0.085 (12) | 0.005 (9) | 0.003 (10) | −0.016 (10) |
C6 | 0.132 (19) | 0.075 (13) | 0.22 (3) | 0.030 (12) | 0.02 (2) | −0.019 (17) |
C7 | 0.073 (10) | 0.050 (10) | 0.062 (9) | 0.002 (9) | 0.014 (8) | 0.020 (9) |
C8 | 0.138 (17) | 0.16 (2) | 0.18 (2) | 0.053 (17) | −0.055 (16) | −0.124 (19) |
N1 | 0.064 (6) | 0.074 (8) | 0.057 (6) | −0.003 (6) | 0.002 (6) | 0.006 (7) |
N2 | 0.078 (8) | 0.061 (7) | 0.078 (8) | 0.015 (7) | 0.014 (8) | −0.002 (7) |
N3 | 0.079 (8) | 0.072 (8) | 0.072 (8) | −0.024 (6) | −0.018 (7) | −0.001 (7) |
N4 | 0.069 (7) | 0.072 (8) | 0.046 (6) | 0.005 (6) | −0.006 (6) | 0.005 (6) |
N5 | 0.093 (11) | 0.048 (8) | 0.161 (15) | −0.015 (8) | −0.001 (12) | 0.003 (12) |
N6 | 0.063 (7) | 0.110 (11) | 0.073 (8) | 0.004 (7) | −0.024 (7) | −0.025 (9) |
O1 | 0.070 (6) | 0.051 (6) | 0.092 (7) | −0.003 (5) | −0.005 (6) | −0.002 (6) |
O2 | 0.068 (6) | 0.056 (6) | 0.066 (6) | 0.003 (5) | −0.021 (5) | −0.008 (5) |
S1 | 0.061 (2) | 0.107 (3) | 0.081 (2) | 0.017 (2) | 0.011 (2) | 0.040 (3) |
Mn1 | 0.0554 (10) | 0.0506 (11) | 0.0514 (10) | −0.0027 (9) | −0.0033 (9) | −0.0002 (10) |
Hg1 | 0.0621 (3) | 0.0680 (3) | 0.0573 (2) | 0.0089 (3) | −0.0029 (5) | 0.0093 (5) |
S2 | 0.088 (2) | 0.077 (2) | 0.0551 (19) | 0.030 (2) | 0.003 (2) | −0.0005 (19) |
S3 | 0.120 (3) | 0.070 (2) | 0.072 (2) | −0.017 (2) | −0.041 (3) | 0.009 (2) |
S4 | 0.0521 (18) | 0.074 (2) | 0.073 (2) | 0.0007 (17) | 0.0102 (19) | 0.009 (2) |
Geometric parameters (Å, º) top
C1—N1 | 1.140 (15) | C8—H8A | 0.9600 |
C1—S1 | 1.649 (14) | C8—H8B | 0.9600 |
C2—N2 | 1.144 (14) | C8—H8C | 0.9600 |
C2—S2 | 1.625 (13) | N1—Mn1 | 2.233 (12) |
C3—N3 | 1.136 (16) | N2—Mn1 | 2.214 (12) |
C3—S3 | 1.655 (15) | N3—Mn1 | 2.199 (12) |
C4—N4 | 1.127 (15) | N4—Mn1 | 2.240 (12) |
C4—S4 | 1.641 (14) | N5—H5B | 0.8600 |
C5—O1 | 1.218 (17) | N6—H6D | 0.8600 |
C5—N5 | 1.32 (2) | O1—Mn1 | 2.178 (9) |
C5—H5A | 0.9300 | O2—Mn1 | 2.176 (9) |
C6—N5 | 1.42 (2) | S1—Hg1 | 2.526 (4) |
C6—H6A | 0.9600 | Hg1—S3i | 2.534 (5) |
C6—H6B | 0.9600 | Hg1—S2ii | 2.548 (4) |
C6—H6C | 0.9600 | Hg1—S4iii | 2.563 (4) |
C7—O2 | 1.226 (17) | S2—Hg1iv | 2.548 (4) |
C7—N6 | 1.30 (2) | S3—Hg1v | 2.534 (5) |
C7—H7 | 0.9300 | S4—Hg1vi | 2.563 (4) |
C8—N6 | 1.38 (2) | | |
| | | |
N1—C1—S1 | 179.0 (13) | C7—N6—H6D | 118.6 |
N2—C2—S2 | 178.8 (13) | C8—N6—H6D | 118.6 |
N3—C3—S3 | 176.7 (13) | C5—O1—Mn1 | 128.2 (10) |
N4—C4—S4 | 178.1 (12) | C7—O2—Mn1 | 128.9 (10) |
O1—C5—N5 | 124.7 (16) | C1—S1—Hg1 | 95.2 (5) |
O1—C5—H5A | 117.7 | O2—Mn1—O1 | 87.8 (4) |
N5—C5—H5A | 117.7 | O2—Mn1—N3 | 176.0 (4) |
N5—C6—H6A | 109.5 | O1—Mn1—N3 | 93.0 (4) |
N5—C6—H6B | 109.5 | O2—Mn1—N2 | 88.3 (4) |
H6A—C6—H6B | 109.5 | O1—Mn1—N2 | 175.8 (4) |
N5—C6—H6C | 109.5 | N3—Mn1—N2 | 90.7 (5) |
H6A—C6—H6C | 109.5 | O2—Mn1—N1 | 86.6 (4) |
H6B—C6—H6C | 109.5 | O1—Mn1—N1 | 88.2 (4) |
O2—C7—N6 | 126.6 (16) | N3—Mn1—N1 | 89.5 (5) |
O2—C7—H7 | 116.7 | N2—Mn1—N1 | 90.0 (4) |
N6—C7—H7 | 116.7 | O2—Mn1—N4 | 93.5 (4) |
N6—C8—H8A | 109.5 | O1—Mn1—N4 | 89.3 (4) |
N6—C8—H8B | 109.5 | N3—Mn1—N4 | 90.4 (4) |
H8A—C8—H8B | 109.5 | N2—Mn1—N4 | 92.4 (4) |
N6—C8—H8C | 109.5 | N1—Mn1—N4 | 177.5 (4) |
H8A—C8—H8C | 109.5 | S1—Hg1—S3i | 117.21 (16) |
H8B—C8—H8C | 109.5 | S1—Hg1—S2ii | 109.83 (15) |
C1—N1—Mn1 | 171.3 (12) | S3i—Hg1—S2ii | 104.46 (15) |
C2—N2—Mn1 | 164.8 (12) | S1—Hg1—S4iii | 101.65 (14) |
C3—N3—Mn1 | 175.5 (12) | S3i—Hg1—S4iii | 109.72 (16) |
C4—N4—Mn1 | 171.5 (13) | S2ii—Hg1—S4iii | 114.40 (14) |
C5—N5—C6 | 120.2 (15) | C2—S2—Hg1iv | 97.1 (5) |
C5—N5—H5B | 119.9 | C3—S3—Hg1v | 95.5 (5) |
C6—N5—H5B | 119.9 | C4—S4—Hg1vi | 94.2 (4) |
C7—N6—C8 | 122.9 (15) | | |
| | | |
S1—C1—N1—Mn1 | −117 (83) | C3—N3—Mn1—N4 | −169 (16) |
S2—C2—N2—Mn1 | −87 (72) | C2—N2—Mn1—O2 | −168 (4) |
S3—C3—N3—Mn1 | −5 (40) | C2—N2—Mn1—O1 | −146 (6) |
S4—C4—N4—Mn1 | 104 (44) | C2—N2—Mn1—N3 | 8 (4) |
O1—C5—N5—C6 | 0 (4) | C2—N2—Mn1—N1 | −81 (4) |
O2—C7—N6—C8 | −5 (3) | C2—N2—Mn1—N4 | 99 (4) |
N5—C5—O1—Mn1 | −176.5 (16) | C1—N1—Mn1—O2 | −134 (7) |
N6—C7—O2—Mn1 | 177.6 (12) | C1—N1—Mn1—O1 | −46 (7) |
N1—C1—S1—Hg1 | −168 (86) | C1—N1—Mn1—N3 | 47 (7) |
C7—O2—Mn1—O1 | 0.8 (12) | C1—N1—Mn1—N2 | 138 (7) |
C7—O2—Mn1—N3 | 103 (6) | C1—N1—Mn1—N4 | −41 (14) |
C7—O2—Mn1—N2 | 179.3 (13) | C4—N4—Mn1—O2 | −61 (7) |
C7—O2—Mn1—N1 | 89.2 (12) | C4—N4—Mn1—O1 | −149 (7) |
C7—O2—Mn1—N4 | −88.4 (13) | C4—N4—Mn1—N3 | 118 (7) |
C5—O1—Mn1—O2 | −130.0 (15) | C4—N4—Mn1—N2 | 28 (7) |
C5—O1—Mn1—N3 | 53.9 (16) | C4—N4—Mn1—N1 | −153 (9) |
C5—O1—Mn1—N2 | −152 (6) | C1—S1—Hg1—S3i | −90.6 (5) |
C5—O1—Mn1—N1 | 143.3 (15) | C1—S1—Hg1—S2ii | 28.3 (5) |
C5—O1—Mn1—N4 | −36.5 (15) | C1—S1—Hg1—S4iii | 149.8 (5) |
C3—N3—Mn1—O2 | 0 (21) | N2—C2—S2—Hg1iv | 122 (71) |
C3—N3—Mn1—O1 | 102 (16) | N3—C3—S3—Hg1v | −144 (25) |
C3—N3—Mn1—N2 | −76 (16) | N4—C4—S4—Hg1vi | 20 (45) |
C3—N3—Mn1—N1 | 14 (16) | | |
Symmetry codes: (i) x−1/2, −y+3/2, z; (ii) x−1/2, −y+1/2, z; (iii) −x+3/2, y−1/2, z+1/2; (iv) x+1/2, −y+1/2, z; (v) x+1/2, −y+3/2, z; (vi) −x+3/2, y+1/2, z−1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N5—H5B···O2vii | 0.86 | 2.49 | 3.285 (19) | 154 |
Symmetry code: (vii) x, y+1, z. |
Experimental details
Crystal data |
Chemical formula | [MnHg(C2H5NO)2(SCN)4] |
Mr | 605.99 |
Crystal system, space group | Orthorhombic, Pna21 |
Temperature (K) | 293 |
a, b, c (Å) | 16.1203 (15), 7.7373 (7), 15.2135 (18) |
V (Å3) | 1897.5 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 9.20 |
Crystal size (mm) | 0.23 × 0.18 × 0.13 |
|
Data collection |
Diffractometer | Bruker P4 diffractometer |
Absorption correction | ψ scan (XSCANS; Siemens, 1996) |
Tmin, Tmax | 0.10, 0.30 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2951, 2417, 1656 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.650 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.040, 0.077, 0.98 |
No. of reflections | 2417 |
No. of parameters | 203 |
No. of restraints | 1 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.68, −0.56 |
Absolute structure | Flack (1983), 162 Friedel pairs |
Absolute structure parameter | 0.12 (2) |
Selected geometric parameters (Å, º) topC1—N1 | 1.140 (15) | N2—Mn1 | 2.214 (12) |
C1—S1 | 1.649 (14) | N3—Mn1 | 2.199 (12) |
C2—N2 | 1.144 (14) | N4—Mn1 | 2.240 (12) |
C2—S2 | 1.625 (13) | O1—Mn1 | 2.178 (9) |
C3—N3 | 1.136 (16) | O2—Mn1 | 2.176 (9) |
C3—S3 | 1.655 (15) | S1—Hg1 | 2.526 (4) |
C4—N4 | 1.127 (15) | S2—Hg1i | 2.548 (4) |
C4—S4 | 1.641 (14) | S3—Hg1ii | 2.534 (5) |
N1—Mn1 | 2.233 (12) | S4—Hg1iii | 2.563 (4) |
| | | |
N1—C1—S1 | 179.0 (13) | N3—Mn1—N1 | 89.5 (5) |
N2—C2—S2 | 178.8 (13) | N2—Mn1—N1 | 90.0 (4) |
N3—C3—S3 | 176.7 (13) | O2—Mn1—N4 | 93.5 (4) |
N4—C4—S4 | 178.1 (12) | O1—Mn1—N4 | 89.3 (4) |
C1—N1—Mn1 | 171.3 (12) | N3—Mn1—N4 | 90.4 (4) |
C2—N2—Mn1 | 164.8 (12) | N2—Mn1—N4 | 92.4 (4) |
C3—N3—Mn1 | 175.5 (12) | N1—Mn1—N4 | 177.5 (4) |
C4—N4—Mn1 | 171.5 (13) | S1—Hg1—S3iv | 117.21 (16) |
C1—S1—Hg1 | 95.2 (5) | S1—Hg1—S2v | 109.83 (15) |
O2—Mn1—O1 | 87.8 (4) | S3iv—Hg1—S2v | 104.46 (15) |
O2—Mn1—N3 | 176.0 (4) | S1—Hg1—S4vi | 101.65 (14) |
O1—Mn1—N3 | 93.0 (4) | S3iv—Hg1—S4vi | 109.72 (16) |
O2—Mn1—N2 | 88.3 (4) | S2v—Hg1—S4vi | 114.40 (14) |
O1—Mn1—N2 | 175.8 (4) | C2—S2—Hg1i | 97.1 (5) |
N3—Mn1—N2 | 90.7 (5) | C3—S3—Hg1ii | 95.5 (5) |
O2—Mn1—N1 | 86.6 (4) | C4—S4—Hg1iii | 94.2 (4) |
O1—Mn1—N1 | 88.2 (4) | | |
Symmetry codes: (i) x+1/2, −y+1/2, z; (ii) x+1/2, −y+3/2, z; (iii) −x+3/2, y+1/2, z−1/2; (iv) x−1/2, −y+3/2, z; (v) x−1/2, −y+1/2, z; (vi) −x+3/2, y−1/2, z+1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N5—H5B···O2vii | 0.86 | 2.49 | 3.285 (19) | 154 |
Symmetry code: (vii) x, y+1, z. |
Versatile and efficient sources of blue–violet or UV light are of fundamental importance for many applications, such as high-density optical data storage, medical diagnosis, photolithography, underwater communications and laser displays. Second-order nonlinear optical (SONLO) materials capable of efficient frequency conversion of IR or visible laser radiation to visible or UV wavelengths are of considerable interest in these fields (Zhang et al., 2004). Materials with large second-order optical nonlinearities, transparency at all wavelengths involved and stable physicochemical performance (thermal and temporal stability) are needed in order to realise many of these applications. Manganese mercury thiocyanate (MMTC; Yan et al., 1999) and quite a few of its Lewis-base adducts (Wang, Yu, Xu, Lu & Yuan, 2000; Wang, Yu, Xu, Lu, Yuan & Lu, 2000; Wang, Yu, Xu, Lu, Yuan, Liu & Lu, 2000; Yu et al., 2001) have been found to crystallize in acentric structures. All of them exhibit good SONLO effects and a wide transparency wavelength region. To continue this work, a novel compound, the title complex, (I), the N-methylformamide (NMF) adduct of MMTC, has been prepared. The crystal structure of the NMF adduct of cobalt mercury thiocyante, bis(N-methylformamide)tetrakis(thiocyanato)cobalt(II)mercury(II), was reported nearly 20 years ago (Kinoshita & Ouchi, 1986). It crystallizes in a non-centrosymmetric space group, but unfortunately the low-energy d–d transitions present in this compound because of the Co2+ ion are normally observed in the visible light region, which limits its SONLO usefulness. This compound is isostructural with (I). However, (I) has many better characteristics. It possesses a high SONLO effect and a wide optical transparency range. Furthermore, it is very easy to grow large single crystals of high optical quality.
According to the hard and soft acids and bases (HSAB) concept (Pearson, 1966; Balarew & Duhlew, 1984), harder metals show a pronounced affinity for coordination with harder ligands, while softer metals prefer coordination with softer ligands. In the structure of (I), each hard MnII cation is six-coordinated by four hard SCN ligands via their N atoms and two hard NMF ligands via their O atoms in a slightly distorted octahedral geometry; the HgII cation is four-coordinated by four soft SCN ligands via their S atoms in a slightly distorted tetrahedral geometry.
In (I), the two O atoms of the NMF ligands coordinate to the MnII cation in a cis conformation. However, in the similar structure of the DMSO adduct (Wang, Yu, Xu, Lu & Yuan, 2000), two O atoms of the DMSO ligands coordinate to the MnII cation in a trans conformation. This difference is due to the smaller size of NMF molecules compared with DMSO molecules. In (I), the Mn—N [2.199 (12)–2.240 (12) Å] and Mn—O [2.178 (9) and 2.176 (9) Å] bond lengths are all much larger than the sums of the ionic radii (2.13 and 2.02 Å, respectively; Shannon, 1976). The Hg—S bond lengths are in the range 2.526 (4)–2.563 (4) Å, with an average of 2.543 Å, a little larger than the sum of the single-bond covalent radii (2.52 Å; Pauling, 1960). The S—Hg—S bond angles [101.65 (14)–117.21 (16)°] deviate markedly from the typical tetrahedral angle.
The C—N—Mn angles [164.8 (12)–175.5 (12)°] are close to 180°, while the C—S—Hg angles [94.2 (4)–97.1 (5)°] are much smaller than 180° and exhibit significant bending. The C—N and C—S bond lengths are slightly smaller than the accepted triple-bond length of 1.16 Å and the normal single C—S bond length of 1.81 Å, respectively (Reference for standard values?). The SCN groups are quasi-linear [N—C—S angles 176.7 (13)–179.0 (13)°].
The striking feature of this type of complex is the –SCN– bridge, which connects the two metals to form infinite two- or three-dimensional networks; a three-dimensional network is formed in (I).
The macroscopic nonlinear susceptibility of the crystal of (I) may be related to the microscopic hyperpolarizabilities of the dipolar SCN− ions, and to the octupolar distorted MnN4O2 octahedra and HgS4 tetrahedra (Zyss & Ledoux, 1994). The second-harmonic generation (SHG) effect of the crystals has been studied (Kurtz & Perry, 1968) and found to be nearly the same as that of urea. The optical transmission of a crystal of (I) was measured by a Hitachi U-3500 spectrophotometer; it was found that the transparency range is 365–2920 nm.