Retracted: Tetra­kis(pyridine-κN)bis­(thio­cyanato-κN)­chromium(II)

In the mol­ecule of the title complex, [Cr(NCS)₂(C₅H₅N)₄], the Cr^II atom is bonded in a distorted octa­hedral arrangement to two N atoms of two SCN⁻ ligands and four N atoms of four pyridine ligands. The Cr atom is located on a centre of inversion. In the crystal structure, C—H...N hydrogen bonds result in the formation of a supra­molecular network structure.

Key indicators

• Single-crystal X-ray study
• T = 273 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.047
• wR factor = 0.161
• Data-to-parameter ratio = 15.3

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low .......       0.96
PLAT232_ALERT_2_B Hirshfeld Test Diff (M-X)  Cr1    -   N2      ..      11.23 su
PLAT232_ALERT_2_B Hirshfeld Test Diff (M-X)  Cr1    -   N3      ..      12.79 su

Alert level C
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Cr1    -   N1      ..       9.97 su
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         N3
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Cr1
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C11

Alert level G
PLAT794_ALERT_5_G Check Predicted Bond Valency for Cr1         (3)       2.55

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

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

---

S1. Comment

In recent years, interest in the chemistry of metal-oxygen clusters has grown because of their applications in areas including catalysis, materials, chemistry and biochemistry (Pope & Müller, 2001). Aromatic polycyclic compounds, such as pyridine, phenanthroline, quinoline and benzimidazole, have commonly shown π-π stacking in metal complexes (Wu et al., 2003; Pan & Xu, 2004; Liu et al., 2004; Li et al., 2005; Zhong et al., 2007a,b). We herein report the crystal structure of the title compound, (I).

In the molecule of (I), (Fig. 1) the ligand bond lengths and angles are within normal ranges (Allen et al., 1987). The two N atoms of two SCN^- and four N atoms of four pyridine ligands are coordinated to the Cr atom, in a distorted octahedral arrangement (Table 1). The Cr—N distances for the SCN^- and pyridine ligand are 2.057 (2)Å and in the range of [2.161 (2)–2.172 (2) Å], respectively (Table 1).

In the crystal structure, the C—H···N hydrogen bonds result in the formation of a supramolecular network structure (Fig. 2).

Related literature

For related literature, see: Allen et al. (1987); Li et al. (2005); Liu et al. (2004); Pan & Xu (2004); Pope & Müller (2001); Wu et al. (2003); Zhong et al. (2007a,b).

S2. Experimental

Crystals of the title compound were synthesized using hydrothermal method in a Teflon-lined Parr bomb (23 ml), which was then sealed. Lanthanum (III) nitrate hexahydrate (216.4 mg, 0.5 mmol), chromium(II) acetate dihydrate (103.1 mg, 0.5 mmol), potassium thiocyanate (97.1 mg, 1 mmol), pyridine (4 ml), and distilled water (6 g) were placed into the bomb and sealed. The bomb was heated under autogenous pressure for 7 d at 453 K and allowed to cool at room temperature for 24 h. Upon opening the bomb, a clear colourless solution was decanted from small brown crystals. These crystals were washed with distilled water followed by ethanol, and allowed to air-dry at room temperature.

S3. Refinement

H atoms were positioned geometrically, with C—H = 0.93 Å for aromatic H and constrained to ride on their parent atoms, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Siemens, 1996); software used to prepare material for publication: SHELXTL (Siemens, 1996).

Figures

	Fig. 1. The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level [symmetry code (A): 3/2 - x, 3/2 - y, 1 - z].
	Fig. 2. A packing diagram for (I).

Tetrakis(pyridine-κN)bis(thiocyanato-κN)chromium(II)

Crystal data

[Cr(NCS)2(C5H5N)4]	F(000) = 1000
Mr = 484.56	Dx = 1.386 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 4510 reflections
a = 12.4232 (11) Å	θ = 2.3–28.2°
b = 12.9354 (12) Å	µ = 0.69 mm^−1
c = 15.1331 (14) Å	T = 273 K
β = 107.313 (1)°	Block, colourless
V = 2321.7 (4) Å^3	0.31 × 0.30 × 0.16 mm
Z = 4

Data collection

Bruker APEXII area-detector diffractometer	2187 independent reflections
Radiation source: fine-focus sealed tube	1843 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.019
φ and ω scans	θmax = 26.0°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −15→15
Tmin = 0.814, Tmax = 0.897	k = −15→15
7288 measured reflections	l = −18→18

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)] = 0.047	H-atom parameters constrained
wR(F^2) = 0.161	w = 1/[σ^2(Fo^2) + (0.1244P)^2 + 0.7474P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max < 0.001
2187 reflections	Δρmax = 0.93 e Å^−3
143 parameters	Δρmin = −0.51 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: 0.0134 (19)

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
Cr1	0.7500	0.7500	0.5000	0.0358 (3)
S1	1.07279 (8)	0.64366 (7)	0.41890 (7)	0.0776 (4)
N1	0.7869 (2)	0.68986 (19)	0.63983 (16)	0.0552 (6)
N2	0.6398 (2)	0.62220 (19)	0.44152 (16)	0.0560 (6)
N3	0.8863 (2)	0.6721 (2)	0.48200 (18)	0.0608 (6)
C1	0.8410 (3)	0.6007 (3)	0.6647 (2)	0.0666 (8)
H1	0.8658	0.5655	0.6207	0.080*
C2	0.8626 (3)	0.5571 (3)	0.7514 (3)	0.0792 (10)
H2	0.8993	0.4938	0.7648	0.095*
C3	0.8289 (3)	0.6094 (4)	0.8169 (3)	0.0857 (11)
H3	0.8432	0.5830	0.8764	0.103*
C4	0.7737 (4)	0.7014 (4)	0.7931 (3)	0.0848 (11)
H4	0.7504	0.7386	0.8368	0.102*
C5	0.7525 (4)	0.7389 (3)	0.7047 (3)	0.0697 (9)
H5	0.7129	0.8005	0.6892	0.084*
C6	0.6747 (3)	0.5247 (3)	0.4543 (2)	0.0703 (9)
H6	0.7499	0.5122	0.4866	0.084*
C7	0.6049 (4)	0.4405 (3)	0.4222 (3)	0.0861 (11)
H7	0.6319	0.3733	0.4342	0.103*
C8	0.4946 (4)	0.4591 (3)	0.3720 (3)	0.0916 (13)
H8	0.4457	0.4046	0.3483	0.110*
C9	0.4583 (4)	0.5597 (3)	0.3577 (3)	0.0896 (12)
H9	0.3840	0.5744	0.3245	0.108*
C10	0.5323 (3)	0.6375 (3)	0.3926 (3)	0.0708 (9)
H10	0.5066	0.7052	0.3818	0.085*
C11	0.9642 (2)	0.65943 (19)	0.45611 (19)	0.0519 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cr1	0.0318 (4)	0.0365 (4)	0.0401 (4)	0.00192 (18)	0.0124 (2)	−0.00210 (18)
S1	0.0726 (6)	0.0752 (6)	0.1001 (7)	0.0086 (4)	0.0488 (5)	−0.0010 (5)
N1	0.0513 (12)	0.0607 (14)	0.0531 (13)	−0.0014 (11)	0.0149 (10)	−0.0013 (10)
N2	0.0524 (13)	0.0544 (13)	0.0624 (14)	−0.0017 (10)	0.0191 (11)	−0.0037 (10)
N3	0.0533 (13)	0.0643 (14)	0.0680 (15)	0.0041 (11)	0.0229 (12)	−0.0020 (12)
C1	0.0653 (18)	0.0713 (19)	0.0633 (18)	0.0078 (16)	0.0193 (15)	0.0058 (15)
C2	0.070 (2)	0.091 (2)	0.075 (2)	0.0073 (18)	0.0195 (17)	0.0213 (19)
C3	0.073 (2)	0.119 (3)	0.062 (2)	−0.006 (2)	0.0160 (17)	0.023 (2)
C4	0.084 (3)	0.111 (3)	0.064 (2)	−0.005 (2)	0.0297 (19)	−0.009 (2)
C5	0.070 (2)	0.080 (2)	0.061 (2)	−0.0007 (16)	0.0203 (17)	−0.0114 (15)
C6	0.072 (2)	0.0583 (18)	0.083 (2)	−0.0016 (15)	0.0270 (17)	−0.0089 (15)
C7	0.096 (3)	0.061 (2)	0.109 (3)	−0.0131 (19)	0.042 (3)	−0.0133 (19)
C8	0.096 (3)	0.081 (3)	0.104 (3)	−0.038 (2)	0.040 (2)	−0.026 (2)
C9	0.071 (2)	0.094 (3)	0.097 (3)	−0.019 (2)	0.014 (2)	−0.020 (2)
C10	0.0581 (17)	0.071 (2)	0.080 (2)	−0.0016 (15)	0.0146 (16)	−0.0034 (16)
C11	0.0547 (15)	0.0450 (14)	0.0553 (15)	0.0041 (11)	0.0150 (13)	−0.0006 (11)

Geometric parameters (Å, º)

Cr1—N1	2.172 (2)	C2—H2	0.9300
Cr1—N1^i	2.172 (2)	C3—C4	1.368 (7)
Cr1—N2^i	2.161 (2)	C3—H3	0.9300
Cr1—N2	2.161 (2)	C4—C5	1.373 (5)
Cr1—N3^i	2.057 (2)	C4—H4	0.9300
Cr1—N3	2.057 (2)	C5—H5	0.9300
S1—C11	1.622 (3)	C6—C7	1.387 (5)
N1—C1	1.332 (4)	C6—H6	0.9300
N1—C5	1.341 (4)	C7—C8	1.375 (7)
N2—C6	1.330 (4)	C7—H7	0.9300
N2—C10	1.335 (4)	C8—C9	1.373 (6)
N3—C11	1.159 (4)	C8—H8	0.9300
C1—C2	1.379 (5)	C9—C10	1.359 (5)
C1—H1	0.9300	C9—H9	0.9300
C2—C3	1.365 (6)	C10—H10	0.9300
N1—Cr1—N1^i	180	C2—C3—C4	118.6 (3)
N1^i—Cr1—N2	87.17 (9)	C2—C3—H3	120.7
N1—Cr1—N2	92.83 (9)	C4—C3—H3	120.7
N1^i—Cr1—N2^i	92.83 (9)	C3—C4—C5	119.9 (4)
N1^i—Cr1—N3	89.43 (10)	C3—C4—H4	120.0
N1—Cr1—N3	90.57 (10)	C5—C4—H4	120.0
N1^i—Cr1—N3^i	90.57 (10)	N1—C5—C4	122.5 (4)
N2^i—Cr1—N2	180	N1—C5—H5	118.8
N2^i—Cr1—N3^i	90.97 (10)	C4—C5—H5	118.8
N2—Cr1—N3^i	89.03 (10)	N2—C6—C7	123.4 (4)
N2—Cr1—N3	90.97 (10)	N2—C6—H6	118.3
N3^i—Cr1—N3	180	C7—C6—H6	118.3
C1—N1—C5	116.6 (3)	C8—C7—C6	118.3 (4)
C1—N1—Cr1	121.8 (2)	C8—C7—H7	120.9
C5—N1—Cr1	121.5 (2)	C6—C7—H7	120.9
C6—N2—C10	116.8 (3)	C9—C8—C7	118.6 (4)
C6—N2—Cr1	121.8 (2)	C9—C8—H8	120.7
C10—N2—Cr1	121.4 (2)	C7—C8—H8	120.7
C11—N3—Cr1	156.5 (2)	C10—C9—C8	119.2 (4)
N1—C1—C2	124.1 (3)	C10—C9—H9	120.4
N1—C1—H1	117.9	C8—C9—H9	120.4
C2—C1—H1	117.9	N2—C10—C9	123.7 (4)
C3—C2—C1	118.3 (4)	N2—C10—H10	118.1
C3—C2—H2	120.8	C9—C10—H10	118.1
C1—C2—H2	120.8	N3—C11—S1	179.0 (3)

Symmetry code: (i) −x+3/2, −y+3/2, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···N3^i	0.93	2.54	3.063 (5)	116
C1—H1···N3	0.93	2.59	3.120 (4)	117

Symmetry code: (i) −x+3/2, −y+3/2, −z+1.