Dichloro­[cyclo­prop­yl(2-pyridylmethyl­ene)amino]copper(II)

The title compound, [CuCl₂(C₉H₁₀N₂)], is a mononuclear copper(II) complex. The Cu^II ion is coordinated by two N atoms of the Schiff base ligand and by two terminal Cl anions in a distorted tetra­hedral geometry. In the crystal structure, the mol­ecules are linked through inter­molecular C—H...Cl hydrogen bonds, forming chains running along the b axis.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.034
• wR factor = 0.085
• Data-to-parameter ratio = 20.7

checkCIF/PLATON results

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Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.98
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.95
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Cu1    -   Cl1     ..       5.32 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Cu1    -   Cl2     ..       5.64 su

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

   0 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
   1 ALERT type 4 Improvement, methodology, query or suggestion

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S1. Comment

In the past few years there has been a burgeoning effort to identify the biological role of copper, primarily through techniques associated with the interface of biology/biochemistry/coordination chemistry (Collinson & Fenton, 1996; Hossain et al., 1996; Tarafder et al., 2002). It appears that the biological role of copper is primarily in redox reactions and as a biological catalyst, although much remains to be understood (Musie et al., 2003; García-Raso et al., 2003). An extensive effort has been made to prepare and characterize a variety of copper(II) coordination complexes in an attempt to model the physical and chemical behaviour of copper-containing enzymes (Reddy et al., 2000). The peculiarity of copper lies in its ability to form complexes with coordination number four, five and six (Ray et al., 2003; Arnold et al., 2003; Raptopoulou et al., 1998). As part of the investigations in this area, the author reports here a new mononuclear copper(II) complex, (I) (Fig. 1).

The Cu^II ion in (I) is four-coordinated by two N atoms of a Schiff base ligand and by two terminal Cl anions. This CuN₂Cl₂ coordination forms a distorted tetrahedral geometry, with angles subtended at the Cu atom in the range 80.81 (9)–115.94 (3)° (Table 1). The N1—Cu1—N2 bond angle [80.81 (9)°] is much smaller than the other angles around the Cu atom owing to the strain created by the five-membered chelate ring Cu1/N1/C1/C6/N2. All the bond lengths are comparable to those of other Schiff base copper(II) complexes (Pal et al., 2005; Colacio et al., 1998; Shii et al., 1999). The dihedral angle between the pyridine ring and the cyclopropane ring is 85.5 (2)°.

In the crystal structure, the molecules are linked through intermolecular C6—H6···Cl1 hydrogen bonds, forming chains running along the b axis (Table 2 and Fig. 2).

S2. Experimental

Pyridine-2-carboxaldehyde (0.1 mmol, 10.7 mg) and cyclopropylamine (0.1 mmol, 5.7 mg) were dissolved in MeOH (10 ml). The mixture was stirred for 1 h to give a yellow solution, which was added to a stirred aqueous solution (5 ml) of CuCl₂·2H₂O (0.1 mmol, 17.0 mg). The mixture was stirred at room temperature for 30 min and then filtered. The filtrate was kept in air for 18 d, and blue block-shaped crystals formed. The crystals were isolated, washed three times with MeOH and dried in a vacuum desiccator containing anhydrous CaCl₂. Yield 71.2%. Analysis calculated for C₉H₁₀Cl₂N₂Cu: C 38.52, H 3.59, N 9.98%; found: C 38.39, H 3.66, N 10.03%.

S3. Refinement

All H atoms were placed in idealized positions and constrained to ride on their parent atoms, with C—H distances in the range 0.93–0.98 Å and with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. The crystal packing of (I). Intermolecular hydrogen bonds are shown as dashed lines. H atoms not involved in hydrogen bonding have been omitted for clarity.

Dichloro[cyclopropyl(2-pyridylmethylene)amino]copper(II)

Crystal data

[CuCl2(C9H10N2)]	Z = 2
Mr = 280.63	F(000) = 282
Triclinic, P1	Dx = 1.589 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.691 (2) Å	Cell parameters from 5165 reflections
b = 8.730 (2) Å	θ = 2.3–28.4°
c = 8.959 (2) Å	µ = 2.28 mm^−1
α = 98.69 (1)°	T = 298 K
β = 99.18 (1)°	Block, blue
γ = 91.19 (1)°	0.32 × 0.28 × 0.22 mm
V = 586.4 (2) Å^3

Data collection

Bruker SMART CCD area-detector diffractometer	2627 independent reflections
Radiation source: fine-focus sealed tube	2542 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.061
ω scans	θmax = 27.5°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
Tmin = 0.529, Tmax = 0.634	k = −11→11
6677 measured reflections	l = −11→11

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.085	H-atom parameters constrained
S = 1.16	w = 1/[σ^2(Fo^2) + (0.0286P)^2 + 0.2104P] where P = (Fo^2 + 2Fc^2)/3
2627 reflections	(Δ/σ)max < 0.001
127 parameters	Δρmax = 0.36 e Å^−3
0 restraints	Δρmin = −0.43 e Å^−3

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
Cu1	0.17038 (3)	0.24955 (3)	0.86083 (3)	0.03896 (11)
Cl1	0.27626 (10)	0.04620 (8)	0.73185 (9)	0.05968 (19)
Cl2	0.19125 (11)	0.46970 (8)	0.77169 (10)	0.0671 (2)
N1	0.2560 (3)	0.2601 (2)	1.0922 (2)	0.0435 (4)
N2	−0.0681 (2)	0.2068 (2)	0.9287 (2)	0.0418 (4)
C1	0.1231 (3)	0.2318 (3)	1.1668 (3)	0.0420 (5)
C2	0.1483 (4)	0.2354 (4)	1.3228 (3)	0.0592 (7)
H2	0.0541	0.2158	1.3718	0.071*
C3	0.3157 (4)	0.2685 (4)	1.4054 (3)	0.0664 (8)
H3	0.3359	0.2717	1.5110	0.080*
C4	0.4526 (4)	0.2966 (4)	1.3295 (4)	0.0616 (7)
H4	0.5667	0.3182	1.3828	0.074*
C5	0.4174 (3)	0.2920 (3)	1.1734 (3)	0.0529 (6)
H5	0.5097	0.3120	1.1224	0.063*
C6	−0.0515 (3)	0.2013 (3)	1.0706 (3)	0.0438 (5)
H6	−0.1492	0.1782	1.1138	0.053*
C7	−0.2413 (3)	0.1859 (3)	0.8373 (3)	0.0504 (6)
H7	−0.3337	0.1395	0.8822	0.060*
C8	−0.2962 (4)	0.3088 (4)	0.7417 (4)	0.0695 (9)
H8A	−0.4185	0.3368	0.7309	0.083*
H8B	−0.2118	0.3936	0.7440	0.083*
C9	−0.2570 (4)	0.1525 (4)	0.6684 (4)	0.0666 (8)
H9A	−0.1490	0.1421	0.6255	0.080*
H9B	−0.3555	0.0853	0.6124	0.080*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.03951 (16)	0.04364 (17)	0.03519 (17)	0.00016 (11)	0.01141 (11)	0.00550 (11)
Cl1	0.0708 (4)	0.0491 (3)	0.0646 (4)	0.0042 (3)	0.0333 (3)	0.0029 (3)
Cl2	0.0804 (5)	0.0492 (4)	0.0793 (5)	0.0038 (3)	0.0277 (4)	0.0192 (3)
N1	0.0428 (10)	0.0487 (11)	0.0394 (10)	0.0032 (8)	0.0080 (8)	0.0062 (8)
N2	0.0374 (9)	0.0420 (10)	0.0461 (11)	0.0025 (7)	0.0093 (8)	0.0044 (8)
C1	0.0475 (12)	0.0400 (11)	0.0410 (12)	0.0066 (9)	0.0108 (9)	0.0100 (9)
C2	0.0662 (17)	0.0723 (18)	0.0451 (14)	0.0057 (14)	0.0162 (12)	0.0211 (12)
C3	0.0750 (19)	0.084 (2)	0.0405 (15)	0.0078 (16)	0.0026 (13)	0.0178 (14)
C4	0.0553 (15)	0.0718 (18)	0.0521 (16)	0.0079 (13)	−0.0072 (12)	0.0085 (13)
C5	0.0448 (13)	0.0615 (15)	0.0514 (15)	0.0021 (11)	0.0063 (11)	0.0074 (11)
C6	0.0414 (11)	0.0460 (12)	0.0479 (13)	0.0030 (9)	0.0155 (10)	0.0105 (9)
C7	0.0405 (12)	0.0537 (13)	0.0548 (15)	−0.0008 (10)	0.0059 (10)	0.0040 (11)
C8	0.0592 (16)	0.0563 (16)	0.084 (2)	0.0035 (13)	−0.0150 (15)	0.0093 (15)
C9	0.0626 (17)	0.0752 (19)	0.0534 (17)	0.0024 (14)	−0.0039 (13)	−0.0029 (14)

Geometric parameters (Å, º)

Cu1—N1	2.060 (2)	C3—H3	0.9300
Cu1—N2	2.066 (2)	C4—C5	1.376 (4)
Cu1—Cl2	2.2022 (9)	C4—H4	0.9300
Cu1—Cl1	2.2114 (10)	C5—H5	0.9300
N1—C5	1.336 (3)	C6—H6	0.9300
N1—C1	1.345 (3)	C7—C9	1.482 (4)
N2—C6	1.265 (3)	C7—C8	1.497 (4)
N2—C7	1.441 (3)	C7—H7	0.9800
C1—C2	1.375 (4)	C8—C9	1.481 (4)
C1—C6	1.471 (3)	C8—H8A	0.9700
C2—C3	1.380 (4)	C8—H8B	0.9700
C2—H2	0.9300	C9—H9A	0.9700
C3—C4	1.378 (5)	C9—H9B	0.9700
N1—Cu1—N2	80.81 (9)	N1—C5—C4	122.6 (3)
N1—Cu1—Cl2	115.60 (7)	N1—C5—H5	118.7
N2—Cu1—Cl2	114.61 (6)	C4—C5—H5	118.7
N1—Cu1—Cl1	110.24 (7)	N2—C6—C1	119.7 (2)
N2—Cu1—Cl1	114.76 (6)	N2—C6—H6	120.2
Cl2—Cu1—Cl1	115.94 (3)	C1—C6—H6	120.2
C5—N1—C1	118.4 (2)	N2—C7—C9	118.8 (2)
C5—N1—Cu1	129.76 (18)	N2—C7—C8	116.7 (2)
C1—N1—Cu1	111.87 (16)	C9—C7—C8	59.6 (2)
C6—N2—C7	119.1 (2)	N2—C7—H7	116.5
C6—N2—Cu1	112.30 (16)	C9—C7—H7	116.5
C7—N2—Cu1	128.56 (17)	C8—C7—H7	116.5
N1—C1—C2	122.2 (2)	C9—C8—C7	59.7 (2)
N1—C1—C6	115.3 (2)	C9—C8—H8A	117.8
C2—C1—C6	122.5 (2)	C7—C8—H8A	117.8
C1—C2—C3	118.9 (3)	C9—C8—H8B	117.8
C1—C2—H2	120.6	C7—C8—H8B	117.8
C3—C2—H2	120.6	H8A—C8—H8B	114.9
C4—C3—C2	119.2 (3)	C8—C9—C7	60.7 (2)
C4—C3—H3	120.4	C8—C9—H9A	117.7
C2—C3—H3	120.4	C7—C9—H9A	117.7
C5—C4—C3	118.8 (3)	C8—C9—H9B	117.7
C5—C4—H4	120.6	C7—C9—H9B	117.7
C3—C4—H4	120.6	H9A—C9—H9B	114.8
N2—Cu1—N1—C5	−177.4 (2)	C6—C1—C2—C3	−178.5 (3)
Cl2—Cu1—N1—C5	−64.5 (2)	C1—C2—C3—C4	−0.1 (5)
Cl1—Cu1—N1—C5	69.4 (2)	C2—C3—C4—C5	0.6 (5)
N2—Cu1—N1—C1	1.46 (16)	C1—N1—C5—C4	0.2 (4)
Cl2—Cu1—N1—C1	114.43 (15)	Cu1—N1—C5—C4	179.0 (2)
Cl1—Cu1—N1—C1	−111.65 (15)	C3—C4—C5—N1	−0.6 (5)
N1—Cu1—N2—C6	−2.36 (17)	C7—N2—C6—C1	−176.3 (2)
Cl2—Cu1—N2—C6	−116.39 (16)	Cu1—N2—C6—C1	2.9 (3)
Cl1—Cu1—N2—C6	105.79 (16)	N1—C1—C6—N2	−1.7 (3)
N1—Cu1—N2—C7	176.7 (2)	C2—C1—C6—N2	176.6 (2)
Cl2—Cu1—N2—C7	62.7 (2)	C6—N2—C7—C9	−164.6 (3)
Cl1—Cu1—N2—C7	−75.2 (2)	Cu1—N2—C7—C9	16.4 (3)
C5—N1—C1—C2	0.2 (4)	C6—N2—C7—C8	127.1 (3)
Cu1—N1—C1—C2	−178.8 (2)	Cu1—N2—C7—C8	−52.0 (3)
C5—N1—C1—C6	178.6 (2)	N2—C7—C8—C9	109.4 (3)
Cu1—N1—C1—C6	−0.5 (2)	N2—C7—C9—C8	−105.8 (3)
N1—C1—C2—C3	−0.3 (4)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C6—H6···Cl1^i	0.93	2.81	3.573 (2)	140

Symmetry code: (i) −x, −y, −z+2.