Crystal structure of di-μ-iodido-bis{[bis(piperidin-1-yl)methane-κ²N,N′]copper(I)}

The title compound, [Cu₂I₂(C₁₁H₂₂N₂)₂], crystallizes as a symmetric dimer with one quarter of the mol­ecule in the asymmetric unit. The copper(I) atom, the iodine atom and the central methyl­ene C atom of the di(piperidin-1-yl)methane ligand lie on a mirror plane and the complete molecule exhibits point group symmetry 2/m. To the best of our knowledge it is the first di­amine copper(I) complex containing a four-membered chelate ring. Compared to other di­amine copper(I) iodide dimers, the title compound has a short Cu...Cu distance of 2.5137 (11) Å, but a long Cu—N bond length of 2.213 (3) Å. The I—Cu—I angle [121.84 (2)°] is large, and the N—Cu—N angle = 66.61 (13)° is the smallest one found for copper(I) di­amine complexes. As a result of the four-membered ring, the ligands around the copper(I) atom have an extremely distorted tetra­hedral arrangement. In the crystal, there are no significant inter­molecular inter­actions present.

Key indicators

• Single-crystal X-ray study
• T = 173 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.032
• wR factor = 0.070
• Data-to-parameter ratio = 23.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.28 Report
PLAT906_ALERT_3_C Large K value in the Analysis of Variance ......      2.484 Check

Alert level G
PLAT066_ALERT_1_G Predicted and Reported Tmin&Tmax Range Identical          ? Check
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  I1     --  Cu1     ..        7.3 su
PLAT764_ALERT_4_G Overcomplete CIF Bond List Detected (Rep/Expd) .       1.27 Ratio
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600         10 Note

   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
   4 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
   1 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Synthesis and crystallization

The title compound was prepared by dissolving 98 mg (0.51 mmol) of CuI in 2 ml acetone under an inert argon atmosphere. Then 151 mg (0.83 mmol) of di(piperidin-1-yl)methane was added to this solution with stirring. After one week colourless crystals of the title compound were obtained.

S2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The C-bound H atoms were included in calculated positions and treated as riding atoms: C—H = 0.99 Å with U_iso(H) = 1.2U_eq(C).

Related literature

To the best of our knowledge no related diamine complexes with four-membered chelate rings are known. For diamine complexes with five-membered chelate rings, see: Haitko (1984); Garbauskas et al. (1986). For a bipyridine complex containing a copper(I) iodide dimer, see: Huang et al. (2013). For the crystal structure of the µ,µ'-diiodido-bridged dimer, with four-coordinate copper(I), viz. [(py)₂CuI₂Cu(py)₂], see: Dyason et al. (1984).

Structure description

To the best of our knowledge no related diamine complexes with four-membered chelate rings are known. For diamine complexes with five-membered chelate rings, see: Haitko (1984); Garbauskas et al. (1986). For a bipyridine complex containing a copper(I) iodide dimer, see: Huang et al. (2013). For the crystal structure of the µ,µ'-diiodido-bridged dimer, with four-coordinate copper(I), viz. [(py)₂CuI₂Cu(py)₂], see: Dyason et al. (1984).

Synthesis and crystallization

The title compound was prepared by dissolving 98 mg (0.51 mmol) of CuI in 2 ml acetone under an inert argon atmosphere. Then 151 mg (0.83 mmol) of di(piperidin-1-yl)methane was added to this solution with stirring. After one week colourless crystals of the title compound were obtained.

Refinement details

Crystal data, data collection and structure refinement details are summarized in Table 2. The C-bound H atoms were included in calculated positions and treated as riding atoms: C—H = 0.99 Å with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: APEX2 (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014/6 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) and publCIF (Westrip, 2010).

Figures

	Fig. 1. Molecular structure of the title compound, with atom labelling. The displacement ellipsoids are drawn at the 50% probability level.
	Fig. 2. Crystal packing of the title compound viewed along b axis. H-atoms have been omitted for clarity.

Di-µ-iodido-bis{[bis(piperidin-1-yl)methane-κ²N,N']copper(I)}

Crystal data

[Cu2I2(C11H22N2)2]	Dx = 1.841 Mg m^−3
Mr = 745.49	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Cmce	Cell parameters from 38065 reflections
a = 18.718 (4) Å	θ = 2.2–28.2°
b = 8.4175 (15) Å	µ = 3.89 mm^−1
c = 17.074 (3) Å	T = 173 K
V = 2690.1 (8) Å^3	Block, colourless
Z = 4	0.4 × 0.3 × 0.2 mm
F(000) = 1472

Data collection

Bruker APEXII CCD diffractometer	1349 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.096
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	θmax = 28.2°, θmin = 2.2°
Tmin = 0.256, Tmax = 0.459	h = −24→24
38065 measured reflections	k = −11→11
1704 independent reflections	l = −22→22

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.032	H-atom parameters constrained
wR(F^2) = 0.070	w = 1/[σ^2(Fo^2) + (0.0354P)^2 + 0.6685P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
1704 reflections	Δρmax = 0.99 e Å^−3
73 parameters	Δρmin = −0.44 e Å^−3

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
I1	0.5000	0.70816 (3)	0.58360 (2)	0.03716 (12)
Cu1	0.5000	0.40635 (6)	0.55733 (3)	0.03283 (16)
N1	0.56490 (13)	0.2603 (3)	0.63824 (16)	0.0259 (5)
C1	0.5000	0.1792 (5)	0.6679 (3)	0.0299 (10)
H1A	0.5000	0.0670	0.6505	0.036*
H1B	0.5000	0.1806	0.7259	0.036*
C2	0.60139 (18)	0.3498 (4)	0.70093 (19)	0.0333 (7)
H2A	0.6165	0.2756	0.7427	0.040*
H2B	0.5677	0.4274	0.7241	0.040*
C3	0.66608 (19)	0.4367 (4)	0.6694 (2)	0.0444 (9)
H3A	0.6504	0.5176	0.6310	0.053*
H3B	0.6905	0.4924	0.7129	0.053*
C4	0.7177 (2)	0.3238 (5)	0.6306 (3)	0.0497 (10)
H4A	0.7382	0.2510	0.6702	0.060*
H4B	0.7573	0.3844	0.6064	0.060*
C5	0.6785 (2)	0.2285 (5)	0.5680 (2)	0.0460 (9)
H5A	0.6628	0.3006	0.5255	0.055*
H5B	0.7114	0.1490	0.5451	0.055*
C6	0.61428 (18)	0.1448 (4)	0.60214 (19)	0.0333 (8)
H6A	0.5891	0.0858	0.5603	0.040*
H6B	0.6302	0.0674	0.6421	0.040*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
I1	0.0678 (3)	0.02108 (15)	0.02262 (17)	0.000	0.000	−0.00298 (11)
Cu1	0.0540 (4)	0.0219 (3)	0.0225 (3)	0.000	0.000	0.0030 (2)
N1	0.0293 (13)	0.0222 (11)	0.0262 (13)	0.0010 (10)	0.0021 (11)	−0.0001 (10)
C1	0.032 (3)	0.028 (2)	0.029 (3)	0.000	0.000	0.0092 (18)
C2	0.0359 (19)	0.0369 (17)	0.0271 (17)	0.0032 (14)	−0.0048 (14)	−0.0078 (14)
C3	0.040 (2)	0.041 (2)	0.052 (2)	−0.0066 (16)	−0.0035 (17)	−0.0046 (17)
C4	0.036 (2)	0.051 (2)	0.062 (3)	−0.0062 (17)	0.0047 (19)	0.0075 (19)
C5	0.043 (2)	0.047 (2)	0.048 (2)	0.0054 (18)	0.0177 (17)	0.0000 (18)
C6	0.040 (2)	0.0289 (16)	0.0314 (18)	0.0033 (14)	0.0023 (15)	−0.0046 (13)

Geometric parameters (Å, º)

Cu1—Cu1^i	2.5137 (11)	C2—H2A	0.9900
I1—Cu1	2.5798 (8)	C2—H2B	0.9900
I1—Cu1^i	2.5922 (7)	C3—C4	1.509 (5)
Cu1—N1	2.213 (3)	C3—H3A	0.9900
Cu1—N1^ii	2.213 (3)	C3—H3B	0.9900
Cu1—I1^i	2.5922 (7)	C4—C5	1.526 (6)
N1—C6	1.476 (4)	C4—H4A	0.9900
N1—C2	1.477 (4)	C4—H4B	0.9900
N1—C1	1.483 (3)	C5—C6	1.509 (5)
C1—N1^ii	1.483 (3)	C5—H5A	0.9900
C1—H1A	0.9900	C5—H5B	0.9900
C1—H1B	0.9900	C6—H6A	0.9900
C2—C3	1.513 (5)	C6—H6B	0.9900
Cu1—I1—Cu1^i	58.16 (2)	C3—C2—H2B	109.4
N1—Cu1—N1^ii	66.61 (13)	H2A—C2—H2B	108.0
N1—Cu1—Cu1^i	146.59 (7)	C4—C3—C2	111.4 (3)
N1^ii—Cu1—Cu1^i	146.59 (7)	C4—C3—H3A	109.4
N1—Cu1—I1	116.02 (7)	C2—C3—H3A	109.4
N1^ii—Cu1—I1	116.01 (7)	C4—C3—H3B	109.4
Cu1^i—Cu1—I1	61.17 (2)	C2—C3—H3B	109.4
N1—Cu1—I1^i	111.90 (7)	H3A—C3—H3B	108.0
N1^ii—Cu1—I1^i	111.90 (7)	C3—C4—C5	109.3 (3)
Cu1^i—Cu1—I1^i	60.67 (3)	C3—C4—H4A	109.8
I1—Cu1—I1^i	121.84 (2)	C5—C4—H4A	109.8
C6—N1—C2	110.4 (2)	C3—C4—H4B	109.8
C6—N1—C1	110.6 (3)	C5—C4—H4B	109.8
C2—N1—C1	111.5 (3)	H4A—C4—H4B	108.3
C6—N1—Cu1	116.7 (2)	C6—C5—C4	111.0 (3)
C2—N1—Cu1	115.02 (19)	C6—C5—H5A	109.4
C1—N1—Cu1	91.11 (18)	C4—C5—H5A	109.4
N1^ii—C1—N1	110.0 (3)	C6—C5—H5B	109.4
N1^ii—C1—H1A	109.7	C4—C5—H5B	109.4
N1—C1—H1A	109.7	H5A—C5—H5B	108.0
N1^ii—C1—H1B	109.7	N1—C6—C5	110.6 (3)
N1—C1—H1B	109.7	N1—C6—H6A	109.5
H1A—C1—H1B	108.2	C5—C6—H6A	109.5
N1—C2—C3	111.0 (3)	N1—C6—H6B	109.5
N1—C2—H2A	109.4	C5—C6—H6B	109.5
C3—C2—H2A	109.4	H6A—C6—H6B	108.1
N1—C2—H2B	109.4
C6—N1—C1—N1^ii	−128.9 (3)	C2—C3—C4—C5	54.5 (4)
C2—N1—C1—N1^ii	107.7 (3)	C3—C4—C5—C6	−55.1 (4)
Cu1—N1—C1—N1^ii	−9.8 (3)	C2—N1—C6—C5	−59.2 (4)
C6—N1—C2—C3	58.5 (3)	C1—N1—C6—C5	176.9 (3)
C1—N1—C2—C3	−178.0 (3)	Cu1—N1—C6—C5	74.6 (3)
Cu1—N1—C2—C3	−76.1 (3)	C4—C5—C6—N1	57.9 (4)
N1—C2—C3—C4	−56.9 (4)

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