Bis{2-[(2-pyrid­yl)imino­meth­yl]phenolato}copper(II)

Abstract

In the title compound, [Cu(C₁₂H₉N₂O)₂], the Cu^II atom lies on a crystallographic inversion center and has a nearly square-planar geometry. The Cu^II center coordinates to the phenolic O and azomethine N atoms of the two symmetry-related 2-[(2-pyrid­yl)imino­meth­yl]phenolate ligands. The pyridyl N atoms do not coordinate to the Cu^II atom but participate in intra­molecular C—H⋯N hydrogen bonding. π–π stacking between the benzene rings and between the pyridyl rings [centroid–centroid distances 3.8142 (5) and 3.8142 (5) Å, respectively] links the mol­ecules into a chain propagating parallel to [100].

Related literature

For the preparation of the title compound by an electrochemical method, see: Castineiras et al. (1989 ▶), and by a solution method, see: Parashar et al. (1988 ▶). For the crystal structures of related compounds, see: Castineiras et al. (1989 ▶).

Experimental

Crystal data

• [Cu(C₁₂H₉N₂O)₂]

• M _r = 457.96

• Triclinic,

• a = 3.8142 (5) Å

• b = 11.217 (1) Å

• c = 11.9001 (12) Å

• α = 106.884 (2)°

• β = 90.374 (1)°

• γ = 90.289 (1)°

• V = 487.16 (9) ų

• Z = 1

• Mo Kα radiation

• μ = 1.15 mm⁻¹

• T = 298 K

• 0.41 × 0.17 × 0.15 mm

Data collection

• Bruker SMART 1000 CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.650, T _max = 0.846

• 2547 measured reflections

• 1695 independent reflections

• 1481 reflections with I > 2σ(I)

• R _int = 0.015

Refinement

• R[F ² > 2σ(F ²)] = 0.033

• wR(F ²) = 0.077

• S = 1.07

• 1695 reflections

• 142 parameters

• H-atom parameters constrained

• Δρ_max = 0.27 e Å⁻³

• Δρ_min = −0.29 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; 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.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯N1	0.93	2.29	2.684 (3)	105

supplementary crystallographic information

Comment

The Schiff base, N-salicylidene 2-aminopyridine, has been widely studied as a potential tridentate ligand. The title compound has been prepared using an electrochemical method by Castineiras et al. (1989) starting from N-salicylidene 2-aminopyridine and copper. Parashar et al. (1988) reported that refluxing a mixture of Cu(OAc)₂ (OAc = acetato) and N-salicylidene 2-aminopyridine in a 1:2 molar ratio resulted in a green complex having the same formula but with an octahedral geometry deduced from spectroscopic properties. We have found that a simple method of solution diffusion produces the brown title compound.

As shown in Fig. 1, the copper atom lies on a crystallographic inversion center and has a square planar geometry. The copper center coordinates to the phenolic oxygen and the azomethine nitrogen atoms of the two symmetry related groups. The pyridyl nitrogen atoms do not coordinate to the copper. The Cu—O bond lengths are 1.9212 (17) Å, and the Cu—N bond lengths are 2.0216 (19) Å, respectively, all similar to those reported in the related structures (Castineiras et al., 1989).

The interplane dihedral angles are found to be as follows: 31.60 (7)° between the N₂O₂ plane and the benzene ring, 54.28 (7)° between the N₂O₂ plane and the pyridyl ring, and 22.75 (9)° between the benzene and the pyridyl ring. The intramolecular hydrogen bond C1—H1···N1 (2.684 (3) Å, 105°, Table 1) further stabilizes the whole structure. The π-π stacking between the benzene rings (centroid to centroid, 3.8142 (5) Å) and the pyridyl rings (centroid to centroid, 3.8142 (5) Å) links the molecules into a one-dimensional chain (Fig. 2).

Experimental

To a green solution of salicylaldehyde (23 mg, 0.19 mmol) and Cu(OAc)₂.H₂O (11 mg, 0.05 mmol) in ethanol (7 ml) was added slowly a solution of 2-aminopyridine (21 mg, 0.22 mmol) in ethanol (1 ml). The resulting mixture was allowed to stand still and brown crystalline needles were grown after 1 day. IR (KBr): v = 3435, 1611, 1444, 1326, 1187 cm ^-1.

Refinement

All H-atoms were positioned geometrically and refined using a riding model with d(C—H) = 0.93 Å, U_iso=1.2U_eq (C).

Figures

Fig. 1.

The molecular structure, with atom labels and 25% probability thermal ellipsoids.

Fig. 2.

The one-dimensional chain constructed by the π-π stacking.

Crystal data

[Cu(C12H9N2O)2]	Z = 1
Mr = 457.96	F(000) = 235
Triclinic, P1	Dx = 1.561 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 3.8142 (5) Å	Cell parameters from 1475 reflections
b = 11.217 (1) Å	θ = 2.2–27.5°
c = 11.9001 (12) Å	µ = 1.15 mm−1
α = 106.884 (2)°	T = 298 K
β = 90.374 (1)°	Needle, brown
γ = 90.289 (1)°	0.41 × 0.17 × 0.15 mm
V = 487.16 (9) Å3

Data collection

Bruker SMART 1000 CCD area-detector diffractometer	1695 independent reflections
Radiation source: fine-focus sealed tube	1481 reflections with I > 2σ(I)
graphite	Rint = 0.015
φ and ω scans	θmax = 25.0°, θmin = 1.8°
Absorption correction: multi-scan (SADABS; Bruker, 2001)	h = −4→4
Tmin = 0.650, Tmax = 0.846	k = −13→13
2547 measured reflections	l = −9→14

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.077	H-atom parameters constrained
S = 1.07	w = 1/[σ2(Fo2) + (0.0266P)2 + 0.355P] where P = (Fo2 + 2Fc2)/3
1695 reflections	(Δ/σ)max < 0.001
142 parameters	Δρmax = 0.27 e Å−3
0 restraints	Δρmin = −0.29 e Å−3

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

	x	y	z	Uiso*/Ueq
Cu1	0.5000	0.5000	0.5000	0.03882 (17)
N1	0.2225 (6)	0.15806 (19)	0.55001 (19)	0.0400 (5)
N2	0.4891 (5)	0.31537 (17)	0.48298 (17)	0.0305 (5)
O1	0.8250 (5)	0.46999 (15)	0.37229 (15)	0.0413 (5)
C1	0.5395 (7)	0.2344 (2)	0.3821 (2)	0.0331 (6)
H1	0.4927	0.1517	0.3774	0.040*
C2	0.6590 (7)	0.2583 (2)	0.2773 (2)	0.0325 (6)
C3	0.7979 (7)	0.3757 (2)	0.2770 (2)	0.0326 (6)
C4	0.9196 (7)	0.3865 (3)	0.1691 (2)	0.0389 (6)
H4	1.0121	0.4623	0.1658	0.047*
C5	0.9057 (7)	0.2886 (3)	0.0689 (2)	0.0459 (7)
H5	0.9870	0.2994	−0.0010	0.055*
C6	0.7726 (8)	0.1734 (3)	0.0696 (2)	0.0494 (7)
H6	0.7657	0.1072	0.0011	0.059*
C7	0.6524 (8)	0.1595 (2)	0.1727 (2)	0.0427 (7)
H7	0.5635	0.0825	0.1738	0.051*
C8	0.4001 (6)	0.2651 (2)	0.5769 (2)	0.0316 (6)
C9	0.5106 (7)	0.3277 (3)	0.6892 (2)	0.0412 (6)
H9	0.6317	0.4030	0.7045	0.049*
C10	0.4374 (8)	0.2761 (3)	0.7780 (3)	0.0494 (7)
H10	0.5085	0.3160	0.8547	0.059*
C11	0.2574 (8)	0.1647 (3)	0.7520 (3)	0.0509 (8)
H11	0.2045	0.1278	0.8105	0.061*
C12	0.1583 (8)	0.1094 (3)	0.6381 (3)	0.0491 (8)
H12	0.0394	0.0335	0.6208	0.059*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Cu1	0.0584 (3)	0.0241 (2)	0.0318 (3)	−0.0022 (2)	0.0154 (2)	0.00443 (18)
N1	0.0457 (14)	0.0298 (11)	0.0452 (13)	−0.0023 (10)	0.0071 (11)	0.0116 (10)
N2	0.0343 (12)	0.0261 (10)	0.0306 (11)	−0.0019 (9)	0.0037 (9)	0.0073 (9)
O1	0.0597 (13)	0.0304 (9)	0.0301 (10)	−0.0079 (9)	0.0143 (9)	0.0029 (8)
C1	0.0363 (15)	0.0233 (12)	0.0375 (14)	0.0001 (10)	0.0005 (11)	0.0054 (11)
C2	0.0341 (14)	0.0286 (13)	0.0312 (13)	0.0052 (11)	0.0027 (11)	0.0030 (10)
C3	0.0335 (14)	0.0330 (13)	0.0290 (13)	0.0046 (11)	0.0036 (11)	0.0051 (11)
C4	0.0384 (16)	0.0444 (15)	0.0339 (14)	−0.0010 (12)	0.0047 (12)	0.0112 (12)
C5	0.0437 (17)	0.065 (2)	0.0258 (14)	0.0025 (14)	0.0037 (12)	0.0081 (13)
C6	0.0526 (19)	0.0517 (18)	0.0318 (15)	0.0027 (14)	0.0007 (13)	−0.0071 (13)
C7	0.0480 (17)	0.0340 (14)	0.0391 (15)	0.0012 (12)	0.0020 (13)	−0.0006 (12)
C8	0.0324 (14)	0.0280 (12)	0.0363 (14)	0.0036 (10)	0.0045 (11)	0.0120 (11)
C9	0.0401 (16)	0.0438 (16)	0.0404 (16)	−0.0012 (12)	−0.0032 (12)	0.0136 (13)
C10	0.0501 (18)	0.064 (2)	0.0370 (16)	0.0118 (15)	0.0021 (13)	0.0186 (14)
C11	0.0545 (19)	0.0555 (19)	0.0544 (19)	0.0185 (15)	0.0182 (15)	0.0336 (16)
C12	0.0541 (19)	0.0367 (15)	0.063 (2)	0.0027 (13)	0.0179 (15)	0.0240 (14)

Geometric parameters (Å, °)

Cu1—O1	1.9212 (17)	C4—H4	0.9300
Cu1—O1i	1.9212 (17)	C5—C6	1.388 (4)
Cu1—N2i	2.0216 (19)	C5—H5	0.9300
Cu1—N2	2.0216 (19)	C6—C7	1.363 (4)
N1—C8	1.330 (3)	C6—H6	0.9300
N1—C12	1.339 (3)	C7—H7	0.9300
N2—C1	1.294 (3)	C8—C9	1.379 (4)
N2—C8	1.433 (3)	C9—C10	1.373 (4)
O1—C3	1.310 (3)	C9—H9	0.9300
C1—C2	1.426 (3)	C10—C11	1.376 (4)
C1—H1	0.9300	C10—H10	0.9300
C2—C7	1.406 (3)	C11—C12	1.366 (4)
C2—C3	1.419 (3)	C11—H11	0.9300
C3—C4	1.406 (3)	C12—H12	0.9300
C4—C5	1.366 (4)
O1—Cu1—O1i	180.000 (1)	C4—C5—H5	119.4
O1—Cu1—N2i	90.50 (8)	C6—C5—H5	119.4
O1i—Cu1—N2i	89.50 (7)	C7—C6—C5	118.6 (3)
O1—Cu1—N2	89.50 (7)	C7—C6—H6	120.7
O1i—Cu1—N2	90.50 (8)	C5—C6—H6	120.7
N2i—Cu1—N2	180.000 (1)	C6—C7—C2	121.8 (3)
C8—N1—C12	116.8 (2)	C6—C7—H7	119.1
C1—N2—C8	115.7 (2)	C2—C7—H7	119.1
C1—N2—Cu1	120.87 (16)	N1—C8—C9	123.6 (2)
C8—N2—Cu1	123.30 (15)	N1—C8—N2	117.7 (2)
C3—O1—Cu1	123.48 (16)	C9—C8—N2	118.7 (2)
N2—C1—C2	127.1 (2)	C10—C9—C8	118.3 (3)
N2—C1—H1	116.4	C10—C9—H9	120.9
C2—C1—H1	116.4	C8—C9—H9	120.9
C7—C2—C3	119.6 (2)	C9—C10—C11	119.2 (3)
C7—C2—C1	118.2 (2)	C9—C10—H10	120.4
C3—C2—C1	122.1 (2)	C11—C10—H10	120.4
O1—C3—C4	120.4 (2)	C12—C11—C10	118.4 (3)
O1—C3—C2	122.7 (2)	C12—C11—H11	120.8
C4—C3—C2	116.9 (2)	C10—C11—H11	120.8
C5—C4—C3	121.8 (3)	N1—C12—C11	123.8 (3)
C5—C4—H4	119.1	N1—C12—H12	118.1
C3—C4—H4	119.1	C11—C12—H12	118.1
C4—C5—C6	121.3 (3)
O1—Cu1—N2—C1	−29.5 (2)	C3—C4—C5—C6	−0.5 (4)
O1i—Cu1—N2—C1	150.5 (2)	C4—C5—C6—C7	0.5 (4)
O1—Cu1—N2—C8	155.47 (19)	C5—C6—C7—C2	0.2 (4)
O1i—Cu1—N2—C8	−24.53 (19)	C3—C2—C7—C6	−0.8 (4)
N2i—Cu1—O1—C3	−138.9 (2)	C1—C2—C7—C6	−177.8 (3)
N2—Cu1—O1—C3	41.1 (2)	C12—N1—C8—C9	−1.5 (4)
C8—N2—C1—C2	−174.2 (2)	C12—N1—C8—N2	176.5 (2)
Cu1—N2—C1—C2	10.4 (4)	C1—N2—C8—N1	−30.6 (3)
N2—C1—C2—C7	−171.7 (3)	Cu1—N2—C8—N1	144.60 (19)
N2—C1—C2—C3	11.3 (4)	C1—N2—C8—C9	147.5 (2)
Cu1—O1—C3—C4	149.6 (2)	Cu1—N2—C8—C9	−37.2 (3)
Cu1—O1—C3—C2	−32.7 (3)	N1—C8—C9—C10	0.8 (4)
C7—C2—C3—O1	−177.1 (2)	N2—C8—C9—C10	−177.2 (2)
C1—C2—C3—O1	−0.2 (4)	C8—C9—C10—C11	−0.1 (4)
C7—C2—C3—C4	0.7 (4)	C9—C10—C11—C12	0.0 (4)
C1—C2—C3—C4	177.6 (2)	C8—N1—C12—C11	1.5 (4)
O1—C3—C4—C5	177.8 (2)	C10—C11—C12—N1	−0.8 (5)
C2—C3—C4—C5	−0.1 (4)

Symmetry codes: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···N1	0.93	2.29	2.684 (3)	105