trans-Dichloridotetra­pyrazine­ruthenium(II) dichloro­methane disolvate

In the title compound, [RuCl₂(C₄H₄N₂)₄]·2CH₂Cl₂, the Ru^II atom occupies a position of 222 symmetry and the C atom of the solvent mol­ecule occupies a site with twofold symmetry. The Ru^II atom has a slightly distorted octa­hedral geometry. The pyrazine rings are propeller-like and rotated 45.1 (1)° from the RuN₄ plane. In the crystal, the complex and solvent mol­ecules are bridged by weak C—H...N hydrogen bonds along the c axis. Weak inter­molecular C—H...Cl contacts link the complexes in the ab plane, forming a network.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.016
• wR factor = 0.040
• Data-to-parameter ratio = 17.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.68
PLAT480_ALERT_4_C Long H...A H-Bond Reported H3A    ..  CL1     ..       2.88 Ang.

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.04
           From the CIF: _reflns_number_total               1399
           Count of symmetry unique reflns          890
           Completeness (_total/calc)            157.19%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       509
           Fraction of Friedel pairs measured     0.572
           Are heavy atom types Z>Si present        yes
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT152_ALERT_1_G The Supplied and Calc. Volume s.u. Differ by ...          2 Units
PLAT164_ALERT_4_G Nr. of Refined C-H H-Atoms in Heavy-Atom Struct.          1
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  Ru1    --  N1      ..        5.3 su

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   2 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   5 ALERT level G = General information/check it is not something unexpected

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

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S1. Comment

The pyrazine ligands are rotated 45.1 (1)° from the N—Ru—N plane (Fig. 1) consistent with other propeller-like structures (Coe et al., 1995 and references therein). The terminal chloride atoms on the Ru(pz)₄Cl₂ complexes are 2.86 - 2.94 Å from the four hydrogen atoms belonging to neighboring pyrazine groups (Fig. 2). This additional interaction enhances the stability of the propeller-like structure.

The Ru—Cl bond length is 2.3920 (5) Å and the Ru—N bond length is 2.0620 (14) Å. These distances are on the low side of the narrow range of bond lengths when this complex is used in supramolecular assemblies (Carlucci et al., 2002), indicating very little influence on bond distance upon further coordination of this metal-based building block. Ru—N distances in tetrakis(pyridine)RuL₂, are 2.09 Å (L = 2-chlorophenylcyanamide) (Desjardins, et al., 1999), or 2.08 Å (L = one chloride and one benzonitrile) (Coe et al., 1995).

H-bonds and intermolecular contacts form a network in the crystal. Atom Cl1 has an intermolecular contact with a hydrogen atom on two pyrazine ligands on a neighboring complex (Fig. 3 and Table 1). At the same time, the hydrogen atoms of the dichloromethane solvate have weak hydrogen bonds between two terminal N-atoms on the pyrazine ligands of two separate Ru(pz)₄Cl₂ complexes (Fig. 4 and Table 1). Additionally, the solvent chloride atom is 3.383 (3) Å from the C2 atom near the uncoordinated nitrogen on the pyrazine ligand.

Related literature

The synthesis of the title complex and its use as a building block in coordination networks are described by Carlucci et al. (2002) and Coe (2004). For related structures using pyridine and varying trans ligands, see: Coe et al. (1995); Desjardins et al. (1999).

S2. Experimental

The ruthenium complex was synthesized by the student co-authors in the laboratory component of Austin College's advanced inorganic course according to procedures by Carlucci et al. (2002) and Coe (2004). Crystals of the title compound were grown from a slow diffusion of hexanes into a solution of the ruthenium complex dissolved in dichloromethane.

S3. Refinement

The H atoms attached to C atoms of the pyrazine molecules were placed in idealized positions (C—H = 0.95 Å) and allowed to ride on their parent atoms. Their positions were constrained so that the U_iso(H) was equal to 1.2U_eq of their respective parent atoms. The solvent molecule, CH₂Cl₂, occupies a special position in the unit cell so the H atom was located using a difference map and was refined with a constrained U_iso(H) equal to 1.2U_eq of its parent atom.

The maximum and minimum residual electron density peaks of 1.01 and 0.37 eÅ^-3, respectively, were located 1.44 Å and 0.76 Å from the H4A and Ru1 atoms, respectively, with the large residue most likely due to imperfect absorption corrections frequently encountered in heavy-metal atom structures.

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. View of the title compound with 50% probability displacement ellipsoids.
	Fig. 2. View of the title compound showing intramolecular Cl···H contacts.
	Fig. 3. Fragment of the crystal packing of the compound along a c axis (dashed lines are Cl···H contacts).
	Fig. 4. Fragment of the crystal packing of the compound along an a axis (dashed lines are C—H···N H-bonds).

trans-Dichloridotetrapyrazineruthenium(II) dichloromethane disolvate

Crystal data

[RuCl2(C4H4N2)4]·2CH2Cl2	Dx = 1.740 Mg m^−3
Mr = 662.19	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, I4122	Cell parameters from 8671 reflections
Hall symbol: I 4bw 2bw	θ = 2.8–27.0°
a = 7.3059 (2) Å	µ = 1.28 mm^−1
c = 47.3659 (16) Å	T = 100 K
V = 2528.21 (14) Å^3	Plate, black
Z = 4	0.10 × 0.10 × 0.08 mm
F(000) = 1320

Data collection

Bruker APEXII CCD diffractometer	1399 independent reflections
Radiation source: fine-focus sealed tube	1363 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.030
ω scans	θmax = 27.0°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Bruker, 1996)	h = −9→9
Tmin = 0.882, Tmax = 0.908	k = −9→9
15409 measured reflections	l = −60→60

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)] = 0.016	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.040	w = 1/[σ^2(Fo^2) + (0.022P)^2 + 2.540P] where P = (Fo^2 + 2Fc^2)/3
S = 1.03	(Δ/σ)max = 0.001
1399 reflections	Δρmax = 1.01 e Å^−3
81 parameters	Δρmin = −0.38 e Å^−3
0 restraints	Absolute structure: Flack (1983), 508 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.26 (4)

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
Ru1	1.0000	0.5000	0.2500	0.01016 (7)
Cl1	0.76849 (5)	0.26849 (5)	0.2500	0.01419 (11)
N1	0.8611 (2)	0.6437 (2)	0.21927 (3)	0.0125 (3)
C1	0.9492 (2)	0.7136 (2)	0.19664 (3)	0.0140 (3)
H1A	1.0775	0.6961	0.1949	0.017*
Cl2	0.74959 (8)	0.41921 (8)	0.141441 (10)	0.02798 (12)
N2	0.6770 (2)	0.8453 (2)	0.17735 (3)	0.0194 (3)
C2	0.8562 (2)	0.8101 (2)	0.17601 (4)	0.0163 (4)
H2A	0.9230	0.8534	0.1601	0.020*
C3	0.5910 (3)	0.7769 (3)	0.19991 (4)	0.0178 (4)
H3A	0.4634	0.7987	0.2019	0.021*
C4	0.6795 (3)	0.6757 (2)	0.22056 (3)	0.0146 (3)
H4A	0.6108	0.6279	0.2359	0.018*
C5	0.6136 (4)	0.2500	0.1250	0.0271 (6)
H5A	0.546 (3)	0.309 (3)	0.1112 (4)	0.033*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ru1	0.00969 (8)	0.00969 (8)	0.01110 (12)	0.00041 (10)	0.000	0.000
Cl1	0.01315 (16)	0.01315 (16)	0.0163 (2)	−0.0024 (2)	−0.00218 (17)	0.00218 (17)
N1	0.0128 (8)	0.0111 (7)	0.0134 (6)	0.0000 (5)	0.0006 (6)	−0.0012 (6)
C1	0.0121 (8)	0.0141 (8)	0.0159 (8)	−0.0009 (6)	0.0015 (6)	−0.0008 (7)
Cl2	0.0296 (3)	0.0277 (3)	0.0266 (3)	−0.0024 (2)	−0.0107 (2)	−0.0016 (2)
N2	0.0207 (8)	0.0184 (8)	0.0191 (7)	0.0031 (6)	−0.0011 (7)	0.0044 (6)
C2	0.0187 (9)	0.0150 (9)	0.0153 (8)	−0.0017 (7)	0.0023 (7)	0.0015 (7)
C3	0.0133 (9)	0.0194 (9)	0.0207 (9)	0.0024 (7)	0.0013 (7)	0.0011 (7)
C4	0.0135 (9)	0.0147 (9)	0.0157 (7)	0.0000 (6)	0.0011 (7)	0.0005 (7)
C5	0.0182 (14)	0.0382 (19)	0.0249 (14)	0.000	0.000	−0.0117 (14)

Geometric parameters (Å, º)

Ru1—N1	2.0620 (14)	Cl2—C5	1.7668 (17)
Ru1—N1^i	2.0620 (14)	N2—C2	1.336 (2)
Ru1—N1^ii	2.0620 (14)	N2—C3	1.337 (2)
Ru1—N1^iii	2.0620 (14)	C2—H2A	0.9500
Ru1—Cl1^iii	2.3920 (5)	C3—C4	1.386 (3)
Ru1—Cl1	2.3920 (5)	C3—H3A	0.9500
N1—C4	1.349 (2)	C4—H4A	0.9500
N1—C1	1.351 (2)	C5—Cl2^iv	1.7668 (17)
C1—C2	1.383 (2)	C5—H5A	0.92 (2)
C1—H1A	0.9500
N1—Ru1—N1^i	89.82 (8)	C1—N1—Ru1	121.20 (12)
N1—Ru1—N1^ii	178.62 (9)	N1—C1—C2	121.29 (16)
N1^i—Ru1—N1^ii	90.20 (7)	N1—C1—H1A	119.4
N1—Ru1—N1^iii	90.20 (7)	C2—C1—H1A	119.4
N1^i—Ru1—N1^iii	178.62 (9)	C2—N2—C3	115.27 (16)
N1^ii—Ru1—N1^iii	89.82 (7)	N2—C2—C1	123.07 (17)
N1—Ru1—Cl1^iii	89.31 (5)	N2—C2—H2A	118.5
N1^i—Ru1—Cl1^iii	90.69 (5)	C1—C2—H2A	118.5
N1^ii—Ru1—Cl1^iii	89.31 (5)	N2—C3—C4	122.98 (17)
N1^iii—Ru1—Cl1^iii	90.69 (5)	N2—C3—H3A	118.5
N1—Ru1—Cl1	90.69 (5)	C4—C3—H3A	118.5
N1^i—Ru1—Cl1	89.31 (5)	N1—C4—C3	121.27 (16)
N1^ii—Ru1—Cl1	90.69 (5)	N1—C4—H4A	119.4
N1^iii—Ru1—Cl1	89.31 (5)	C3—C4—H4A	119.4
Cl1^iii—Ru1—Cl1	180.0	Cl2—C5—Cl2^iv	111.58 (16)
C4—N1—C1	116.08 (15)	Cl2—C5—H5A	106.7 (15)
C4—N1—Ru1	122.71 (12)	Cl2^iv—C5—H5A	108.1 (15)

Symmetry codes: (i) −y+3/2, −x+3/2, −z+1/2; (ii) y+1/2, x−1/2, −z+1/2; (iii) −x+2, −y+1, z; (iv) x, −y+1/2, −z+1/4.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3A···Cl1^v	0.95	2.88	3.555 (2)	129
C5—H5A···N2^vi	0.92 (2)	2.46 (2)	3.338 (2)	158 (2)

Symmetry codes: (v) −x+1, −y+1, z; (vi) −x+1, y−1/2, −z+1/4.