Crystal structure of a low-spin poly[di-μ₃-cyanido-di-μ₂-cyanido-bis­(μ₂-2-ethyl­pyrazine)­dicopper(I)iron(II)]

In the title compound, {Fe(Etpz)₂[Cu(CN)₂]₂}_n, where Etpz is 2-ethyl­pyrazine, the low-spin Fe^II atom lies on an inversion centre and has an elongated octa­hedral [FeN₆] coordination environment, where the axial positions are occupied by two 2-ethyl­pyrazine ligands and the equatorial positions are occupied by two pairs of symmetry-related cyanido groups. Each Cu₂(CN)₂ unit is connected to six Fe^II centres via two bridging 2-ethyl­pyrazine mol­ecules and four cyanido groups, resulting in the formation of a polymeric three-dimensional bimetallic metal–organic framework, additionally stabilized by Cu...Cu contacts.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.030
• wR factor = 0.065
• Data-to-parameter ratio = 16.3

checkCIF/PLATON results

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Datablock: I


Alert level C
PLAT911_ALERT_3_C Missing FCF Refl Between Thmin & STh/L=    0.600          2 Report
PLAT978_ALERT_2_C Number C-C Bonds with Positive Residual Density.          0 Info

Alert level G
PLAT004_ALERT_5_G Polymeric Structure Found with Maximum Dimension          3 Info
PLAT005_ALERT_5_G No Embedded Refinement Details Found  in the CIF     Please Do !
PLAT042_ALERT_1_G Calc. and Reported MoietyFormula Strings  Differ     Please Check
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  Fe1      --N1       .        7.5 s.u.
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  Fe1      --N2       .        6.9 s.u.
PLAT343_ALERT_2_G Unusual sp?      Angle Range in Main Residue for         C2 Check
PLAT794_ALERT_5_G Tentative Bond Valency for Fe1       (III)     .       3.98 Info

   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
   7 ALERT level G = General information/check it is not something unexpected

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 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
   3 ALERT type 5 Informative message, check

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Computing details

Data collection: SAINT (Bruker, 2013); cell refinement: APEX (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

poly[di-µ₃-cyanido-di-µ₂-cyanido-bis(µ₂-2-ethylpyrazine)dicopper(I)iron(II)]

Crystal data

[Cu2Fe(CN)4](C6H8N2)2	F(000) = 1008
Mr = 503.30	Dx = 1.977 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 13.1997 (17) Å	Cell parameters from 1806 reflections
b = 9.2923 (11) Å	θ = 2.7–27.8°
c = 13.8010 (17) Å	µ = 3.36 mm^−1
β = 92.399 (2)°	T = 173 K
V = 1691.3 (4) Å^3	Plate, brown
Z = 4	0.17 × 0.14 × 0.06 mm

Data collection

Bruker SMART diffractometer	1594 reflections with I > 2σ(I)
ω scan	Rint = 0.065
Absorption correction: multi-scan (SADABS; Bruker, 2013)	θmax = 27.9°, θmin = 2.7°
Tmin = 0.614, Tmax = 0.746	h = −17→17
5344 measured reflections	k = −11→12
2022 independent reflections	l = −17→18

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.030	H-atom parameters constrained
wR(F^2) = 0.065	w = 1/[σ^2(Fo^2) + (0.0096P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.93	(Δ/σ)max = 0.001
2022 reflections	Δρmax = 0.71 e Å^−3
124 parameters	Δρmin = −0.47 e Å^−3
0 restraints

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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

	x	y	z	Uiso*/Ueq
Fe1	0.750000	0.250000	0.500000	0.00838 (13)
N3	0.67750 (17)	0.4182 (2)	0.55164 (15)	0.0112 (5)
C6	0.6721 (2)	0.4390 (3)	0.64784 (18)	0.0130 (6)
H6	0.690965	0.363327	0.691266	0.016*
Cu1	0.56898 (3)	−0.12263 (4)	0.69244 (2)	0.01200 (10)
C5	0.6397 (2)	0.5687 (3)	0.68428 (19)	0.0149 (6)
H5	0.636763	0.579116	0.752586	0.018*
N4	0.61203 (18)	0.6806 (2)	0.62788 (16)	0.0123 (5)
C4	0.6133 (2)	0.6591 (3)	0.53050 (18)	0.0116 (6)
C3	0.6452 (2)	0.5271 (3)	0.49461 (18)	0.0126 (6)
H3	0.644046	0.513708	0.426328	0.015*
C7	0.5820 (3)	0.7817 (3)	0.46507 (19)	0.0193 (7)
H7A	0.621459	0.868000	0.485232	0.023*
H7B	0.509562	0.802998	0.474233	0.023*
C8	0.5965 (3)	0.7554 (3)	0.35783 (19)	0.0205 (7)
H8A	0.574269	0.840394	0.320653	0.031*
H8B	0.668292	0.736985	0.347349	0.031*
H8C	0.556167	0.671850	0.336328	0.031*
N2	0.64347 (17)	0.2077 (2)	0.40162 (15)	0.0104 (5)
C2	0.5888 (2)	0.1671 (3)	0.33956 (19)	0.0123 (6)
N1	0.68194 (18)	0.1220 (2)	0.59018 (15)	0.0121 (5)
C1	0.6394 (2)	0.0361 (3)	0.63471 (18)	0.0130 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Fe1	0.0087 (3)	0.0087 (3)	0.0077 (3)	−0.0002 (2)	−0.00018 (19)	0.0000 (2)
N3	0.0117 (12)	0.0109 (12)	0.0109 (11)	0.0007 (9)	0.0009 (9)	0.0007 (9)
C6	0.0172 (14)	0.0111 (13)	0.0106 (13)	0.0016 (12)	0.0010 (11)	0.0027 (11)
Cu1	0.01269 (17)	0.01261 (18)	0.01078 (17)	−0.00052 (14)	0.00136 (12)	0.00098 (14)
C5	0.0177 (14)	0.0178 (14)	0.0093 (13)	0.0025 (13)	0.0016 (11)	0.0004 (12)
N4	0.0130 (12)	0.0123 (12)	0.0117 (11)	0.0021 (10)	0.0022 (9)	−0.0024 (10)
C4	0.0107 (13)	0.0145 (14)	0.0098 (12)	0.0021 (11)	−0.0001 (10)	0.0002 (11)
C3	0.0138 (13)	0.0154 (15)	0.0087 (13)	−0.0003 (12)	0.0004 (10)	−0.0001 (11)
C7	0.0274 (17)	0.0183 (15)	0.0123 (14)	0.0081 (14)	0.0019 (12)	0.0020 (12)
C8	0.0327 (18)	0.0182 (15)	0.0107 (14)	0.0073 (14)	0.0009 (12)	0.0008 (12)
N2	0.0108 (11)	0.0102 (11)	0.0105 (11)	0.0006 (9)	0.0045 (9)	0.0028 (9)
C2	0.0142 (14)	0.0093 (13)	0.0132 (13)	−0.0001 (11)	−0.0016 (11)	−0.0012 (11)
N1	0.0108 (11)	0.0130 (12)	0.0122 (11)	0.0011 (10)	−0.0020 (9)	−0.0039 (10)
C1	0.0118 (13)	0.0163 (15)	0.0110 (13)	0.0022 (12)	0.0013 (10)	−0.0025 (11)

Geometric parameters (Å, º)

Fe1—N3	1.981 (2)	C5—H5	0.9500
Fe1—N3^i	1.981 (2)	C5—N4	1.340 (3)
Fe1—N2	1.953 (2)	N4—C4	1.360 (3)
Fe1—N2^i	1.953 (2)	C4—C3	1.394 (4)
Fe1—N1^i	1.966 (2)	C4—C7	1.501 (4)
Fe1—N1	1.966 (2)	C3—H3	0.9500
N3—C6	1.346 (3)	C7—H7A	0.9900
N3—C3	1.341 (3)	C7—H7B	0.9900
C6—H6	0.9500	C7—C8	1.520 (4)
C6—C5	1.381 (4)	C8—H8A	0.9800
Cu1—Cu1^ii	2.4662 (7)	C8—H8B	0.9800
Cu1—N4^iii	2.122 (2)	C8—H8C	0.9800
Cu1—C2^iv	2.151 (3)	N2—C2	1.160 (3)
Cu1—C2^v	2.078 (3)	N1—C1	1.166 (3)
Cu1—C1	1.933 (3)
N3^i—Fe1—N3	180.0	C6—C5—H5	118.4
N2—Fe1—N3^i	86.31 (9)	N4—C5—C6	123.1 (2)
N2^i—Fe1—N3^i	93.69 (9)	N4—C5—H5	118.4
N2—Fe1—N3	93.69 (9)	C5—N4—Cu1^vi	119.72 (18)
N2^i—Fe1—N3	86.31 (9)	C5—N4—C4	116.5 (2)
N2—Fe1—N2^i	180.0	C4—N4—Cu1^vi	123.81 (18)
N2—Fe1—N1^i	90.94 (9)	N4—C4—C3	119.8 (2)
N2—Fe1—N1	89.06 (9)	N4—C4—C7	118.0 (2)
N2^i—Fe1—N1	90.94 (9)	C3—C4—C7	122.2 (2)
N2^i—Fe1—N1^i	89.06 (9)	N3—C3—C4	123.3 (2)
N1^i—Fe1—N3	89.48 (9)	N3—C3—H3	118.4
N1^i—Fe1—N3^i	90.51 (9)	C4—C3—H3	118.4
N1—Fe1—N3	90.52 (9)	C4—C7—H7A	108.5
N1—Fe1—N3^i	89.48 (9)	C4—C7—H7B	108.5
N1^i—Fe1—N1	180.0	C4—C7—C8	114.9 (2)
C6—N3—Fe1	120.93 (19)	H7A—C7—H7B	107.5
C3—N3—Fe1	122.06 (18)	C8—C7—H7A	108.5
C3—N3—C6	116.2 (2)	C8—C7—H7B	108.5
N3—C6—H6	119.5	C7—C8—H8A	109.5
N3—C6—C5	120.9 (3)	C7—C8—H8B	109.5
C5—C6—H6	119.5	C7—C8—H8C	109.5
N4^iii—Cu1—Cu1^ii	119.23 (6)	H8A—C8—H8B	109.5
N4^iii—Cu1—C2^iv	91.28 (10)	H8A—C8—H8C	109.5
C2^v—Cu1—Cu1^ii	55.71 (8)	H8B—C8—H8C	109.5
C2^iv—Cu1—Cu1^ii	52.95 (7)	C2—N2—Fe1	170.6 (2)
C2^v—Cu1—N4^iii	102.36 (10)	Cu1^vii—C2—Cu1^iv	71.33 (8)
C2^v—Cu1—C2^iv	104.11 (10)	N2—C2—Cu1^vii	146.7 (2)
C1—Cu1—Cu1^ii	130.26 (8)	N2—C2—Cu1^iv	141.4 (2)
C1—Cu1—N4^iii	110.04 (10)	C1—N1—Fe1	172.3 (2)
C1—Cu1—C2^iv	122.70 (11)	N1—C1—Cu1	172.0 (2)
C1—Cu1—C2^v	120.75 (11)
Fe1—N3—C6—C5	167.2 (2)	C5—N4—C4—C3	−1.9 (4)
Fe1—N3—C3—C4	−166.3 (2)	C5—N4—C4—C7	179.5 (3)
N3—C6—C5—N4	−0.1 (5)	N4—C4—C3—N3	−1.4 (4)
C6—N3—C3—C4	3.8 (4)	N4—C4—C7—C8	173.5 (3)
C6—C5—N4—Cu1^vi	−177.6 (2)	C3—N3—C6—C5	−3.1 (4)
C6—C5—N4—C4	2.7 (4)	C3—C4—C7—C8	−5.0 (4)
Cu1^vi—N4—C4—C3	178.3 (2)	C7—C4—C3—N3	177.1 (3)
Cu1^vi—N4—C4—C7	−0.2 (4)

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