Bis(2-{1-[(2,4,6-tri­methyl­phen­yl)imino]­eth­yl}pyrrol-1-ido-κ²N,N′)nickel(II): a supra­molecular structure formed by C—H...π(arene) hydrogen bonds

<!?tlsb=-0.2pt>Nitro­gen-based polydentate ligands are of interest owing to their flexible com­plexation to transition metal atoms. For the title compound, [Ni(C₁₅H₁₇N₂)₂], a transition metal complex formed by the coordination of two identical N,N′-bi­dentate mono(imino)­pyrrolyl ligands to an Ni^II centre, an X-ray crystal diffraction study indicates that the two ligands show an inverted arrangement with respect to one another around the Ni^II centre, which is located on a crystallographic inversion centre. The planes of the aromatic substituents at the imine N atoms of the ligands show dihedral angles of 85.91 (5)° with respect to the NiN₄ plane. The Ni—N bond lengths are in the range 1.9072 (15)–1.9330 (15) Å and the N_imino—Ni—N_pyrrole bite angles are 83.18 (6)°. The Ni—N_pyrrole bond is substanti­ally shorter than the Ni—N_imino bond. Mol­ecules are linked into an extensive network by means of inter­molecular C—H...π(arene) hydrogen bonds in which every mol­ecule acts both as hydrogen-bond donor and acceptor. The supra­molecular assembly takes the form of an infinite two-dimensional sheet.

S1. Introduction

There has been considerable research work on nitro­gen-based polydentate ligands owing to their flexible complexation to transition metal atoms (Small et al., 1998; Gibson et al., 1998; Britovsek et al., 2003; Tenza et al., 2009). One of these studies focused on the syntheses of transition metal complexes with a variety of imino–pyrrolyl ligands (Mashima & Tsurugi, 2005). However, in contrast to the considerable work on symmetric bis­(imino)­pyrrole, there was broader research on the synthesis and the application of asymmetric mono(imino)­pyrrolyl ligands and their transition metal complexes due to the structural diversity of these complexes. In the reported cases, most substituents at the iminic C atom of the mono(imino)­pyrrolyl unit were H atoms (Dawson et al., 2000; Anderson et al., 2006; Carabineiro et al., 2007; Pérez-Puente et al., 2008; Imhof, 2012, 2013). Moreover, the synthetic strategy towards these mono(imino)­pyrrolyl transition metal complexes inevitably employed deprotonation of the pyrrole N—H group (Mashima & Tsurugi, 2005; Tenza et al., 2009). We have made two significant improvements to the previous cases: (i) using a methyl substituent instead of the H atom for the preparation of new mono(imino)­pyrrole compounds; (ii) proposing a simple synthetic route avoiding deprotonation for this kind of mono(imino)­pyrrolyl Ni^II complex (see Scheme).

S2. Experimental

S2.1. Synthesis and crystallization

2,4,6-Tri­methyl-N-[1-(1H-pyrrol-2-yl)ethyl­idene]aniline, (I) (0.100 g, 0.442 mmol), synthesized according to the reported method of Su et al., 2012), was dissolved in methanol (10 ml) in a 50 ml flask. A methanol solution of NiCl₂.6H₂O (0.105 g, 0.442 mmol) was added dropwise to the methanol solution of the above ligand. The mixed solution was stirred at room temperature for 3 h. The red-brown precipitate which formed was filtered off and washed with hexane. The solid was dried under vacuum to yield a red powder. A mixture of chloro­form and acetone (1:1 v:v) was used to dissolve the red powder (methanol and a small amount of water proved to be poor solvents), and pale-red–brown crystals suitable for X-ray diffraction analysis was obtained using the liquid phase diffusion method (yield 69.2%). Analysis calculated for C₃₀H₃₄N₄Ni: C 70.75, H 6.73, N 11.00%; found: C 70.25, H 6.96, N 11.13%. MS (EI): m/z 507 (M⁺). IR (KBr): ν_C═N 1662 cm^-1.

S2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. All H atoms were positioned geometrically and treated using a riding model, with C—H = 0.93 and 0.96 Å for aromatic and methyl H atoms, respectively, and with U_iso(H) = 1.2U_eq(C) and 1.5U_eq(C) for aromatic and methyl H atoms, respectively.

S3. Results and discussion

\ In the title nickel(II) complex, (II), the Ni^II atom is tetra­coordinated by two imine N atoms and two pyrrole N atoms from two N,N'-bidentate mono(imino)­pyrrolyl ligands, namely 2-{1-[(2,4,6-tri­methyl­phenyl)­imino]­ethyl}­pyrrol-1-ide, as shown in Fig. 1. These two ligands show an inverted arrangement with respect to each other. The Ni^II atom is located on a crystallographic inversion centre, meaning that the sum of the angles around this atom is 360°. The pyrrole rings and the imine groups lie trans with respect to each other. The planes of the two benzene rings at the imine N atoms both show dihedral angles of 85.91 (5)° with respect to the NiN₄ square plane and are parallel to each other (0°). The five-membered Ni1/N1/C10/C11/N2 chelate ring is essentially planar, and the maximum deviation from the plane is -0.0288 (11) Å for atom N1. In addition, we notice that Ni—N_imine bond [1.9330 (15) Å] is substanti­ally longer than the Ni—N_pyrrole bond [1.9072 (15) Å] in (II) due to the anionic nature of the pyrrole N atom and the steric bulk of the 2,4,6-tri­methyl­phenyl group. A similar trend was observed in several structures of analogous metal complexes (Anderson et al., 2006; Carabineiro et al., 2007; Imhof, 2012, 2013). The M—N bond lengths in these examples reveal that the M—N_imino bonds are ca 0.01–0.05 Å longer than the corresponding M—N_pyrrole bonds within each metal bidentate chelate unit. The same trend can also be found in the analogue bis­{2-[1-(phenyl­imino)­ethyl]-1H-pyrrol-1-ido-κ²N,N'}\ nickel(II), (III) (Su et al., 2013), with an Ni—N_imine bond length of 1.939 (2) Å and an Ni—N_pyrrole bond length of 1.894 (3) Å. As the Ni—N bond lengths between different complexes are compared, some inter­esting conclusions can be obtained. It is found that the Ni—N_imine distance in complex (II) is slightly shorter than that in (III), while Ni—N_pyrrole are dramatically longer that the latter. This may be because of the introduction of three methyl groups on the benzene ring in complex (II), resulting in a rise in electron density of the iminic N atom and a shortening of the Ni—N_imine bond length, which leads to a increase of the Ni—N_pyrrole bond length and the N_imino—Ni—N_pyrrole angle with the dragging of the Ni—N_imine bond in the five-membered chelate ring. As far as bis­[N,N'-bis­(pyrrolidin-2-yl­methyl)­tetra­methyl­disiloxane-1,3-\ bis­(amino­propyl)]nickel(II), (IV) (Vlad et al., 2012), is concerned, the lower steric hindrance effect of the aliphatic chain becomes a key factor in making the coordination between the Ni^II atom and the N₄ donor set tight; as a result, the Ni—N_imine [1.916 (2) Å] and Ni—N_pyrrole [1.901 (7) Å] bond lengths in this complex are shorter than those in complex (II). Compared with bis­[2-(N-aryl­imino-κN-methyl)­pyrrolide-κN]nickel(II) (Pérez-Puente et al., 2008), the extra methyl groups at the 4-position of the benzene ring and at the iminic C atom in complex (II) also result in dramatic changes in the Ni—N bond lengths. Due to the fact that the electron-donating effect of the methyl group at the 4-position of the benzene ring is stronger than the delocalization effect of lone-pair electron on the iminic N atom, which is caused by a p–π conjugative effect between the methyl group on the iminic C atom and the C═N group in complex (II), the Ni—N_imine bond length becomes longer and the Ni—N_pyrrole distance becomes shorter compared with those in (IV) [Ni—N_imine = 1.93 (8) Å and Ni—N_pyrrole = 1.915 (2) Å]. It is worth mentioning that the above values are all averages.

Comparising the data for the free molecule, i.e. 2-{1-[(2,4,6-tri­methyl­phenyl)­imino]­ethyl}-1H-pyrrole, (I) (Su et al., 2012), and its Ni^II complex also emphasizes some structural differences. The first feature to note is that the N_imino—Ni—N_pyrrole bite angles of the mono(imino)­pyrrolyl ligand are very acute, at 83.18 (6)°, leading to decreases in the N1—C10—C11 and N2—C11—C10 angles [122.9 (2) and 119.2 (2)°, respectively [115.09 (17) and 115.67 (17) in CIF???]] in relation to those observed in free molecule (I) [123.0 (2) and 119.2 (2)°, respectively]. Also, the angles at the pyrrole N atom (C—N_pyrrole—C) decrease upon coordination, which is compensated for by increases of the angles at the C atoms bound to pyrrole N atom. The angle at the imine N atom (C11—N2—C1) decreases and the imine double bonds (C11═N2 and N2═ C1) increase upon coordination, indicating that π-back-donation from the Ni^II centre to the imine fragment is relatively strong.

As depicted in Fig. 2, no classical hydrogen bonds are found in the molecule of complex (II), but it is possible to observe the existence of two inter­molecular C—H···π^ii,iii inter­actions that explain the packing found in the crystal structure (see Table 3). In one of the inter­actions, pyrrole atom C7 acts as the donor, while in the other, pyrrole atom C8 acts as the donor. The molecules are linked into an extensive network by means of inter­molecular C—H···π(arene) hydrogen bonds in which every molecule acts as both a hydrogen-bond donor and acceptor, and the supra­molecular assembly takes the form of infinite two-dimensional sheets. The H···Cg1 (Cg1 is the centroid of the C1–C6 phenyl ring) distances are 2.55 and 2.88 Å, and the C—H···π angles are 151 and 147° for the two types of bonds, respectively. The angles of approach of the H···Cg1 vector to the plane of the aromatic ring are 70.63 and 82.02°, respectively, and the perpendicular projections of the H atoms onto the pyrrole ring plane are 0.84 and 0.40 Å, respectively, from the centroid of the ring. In the former inter­action, the H atom lies above the centre of the ring, with the C—H bond pointing towards a phenyl-ring C atom. This corresponds to a type III inter­action according to the classification of Malone et al. (1997). The latter inter­action corresponds to a type I inter­action, showing the classical T-shaped geometry. Furthermore, it has been acknowledged that these weak C—H···π inter­actions can have a profound effect on the conformations of organic molecules (Umezawa et al., 1999). Due to the supra­molecular inter­actions described above, the crystal packing shows a zigzag arrangement when viewed along the [2, 0, 10] direction, as depicted in Fig. 3.

Computing details

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); 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: publCIF (Westrip, 2010) and PLATON (Spek, 2009).

Figures

	Fig. 1. The molecular structure of complex (II), showing the atom-numbering scheme. Displacement ellipsiods are drawn at 30% probability level. H atoms are presented as small spheres of arbitrary radius. The dashed lines indicate C—H···π interactions. [Symmetry code: (A) -x, -y+2, -z+1.]
	Fig. 2. A view of the unit-cell packing in complex (II), view along a, with the C—H···π hydrogen-bonding scheme shown as dashed lines. H atoms not participating in the C—H···π interactions have been omitted for clarity. The largest spheres indicate the centroids of the C1–C6 rings (Cg1). See Table 3 for symmetry codes.
	Fig. 3. The packing of the crystal structure of complex (II), showing the supramolecular arrangement of the complexes in a zigzag fashion. Dashed lines represent intermolecular C—H···π interactions.

Bis(2-{1-[(2,4,6-trimethylphenyl)imino]ethyl}pyrrol-1-ido-\ κ²N,N')nickel(II)

Crystal data

[Ni(C15H17N2)2]	F(000) = 540
Mr = 509.32	Dx = 1.286 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2440 reflections
a = 7.2045 (10) Å	θ = 3.1–25.7°
b = 15.049 (2) Å	µ = 0.76 mm^−1
c = 12.1405 (16) Å	T = 296 K
β = 91.650 (2)°	Needle, brown
V = 1315.8 (3) Å^3	0.35 × 0.27 × 0.15 mm
Z = 2

Data collection

Bruker APEXII CCD diffractometer	3224 independent reflections
Radiation source: fine-focus sealed tube	2432 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.026
φ and ω scans	θmax = 28.4°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −9→9
Tmin = 0.776, Tmax = 0.894	k = −16→20
8109 measured reflections	l = −15→14

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)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.105	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0536P)^2 + 0.2522P] where P = (Fo^2 + 2Fc^2)/3
3224 reflections	(Δ/σ)max = 0.001
164 parameters	Δρmax = 0.26 e Å^−3
0 restraints	Δρmin = −0.28 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
C1	0.1659 (3)	0.81395 (12)	0.49531 (16)	0.0310 (4)
C2	0.3251 (3)	0.79752 (14)	0.55920 (18)	0.0384 (5)
C3	0.3498 (3)	0.71268 (15)	0.60256 (17)	0.0423 (5)
H3	0.4572	0.7004	0.6442	0.051*
C4	0.2200 (3)	0.64593 (14)	0.58586 (18)	0.0420 (5)
C5	0.0621 (3)	0.66564 (14)	0.52419 (18)	0.0380 (5)
H5	−0.0274	0.6217	0.5134	0.046*
C6	0.0315 (3)	0.74881 (13)	0.47742 (16)	0.0341 (4)
C7	0.0235 (3)	1.12117 (14)	0.29535 (17)	0.0412 (5)
H7	−0.0500	1.1693	0.3142	0.049*
C8	0.1136 (3)	1.11272 (14)	0.19650 (17)	0.0431 (5)
H8	0.1105	1.1531	0.1385	0.052*
C9	0.2082 (3)	1.03369 (15)	0.20042 (17)	0.0418 (5)
H9	0.2827	1.0103	0.1463	0.050*
C10	0.1704 (3)	0.99548 (12)	0.30128 (17)	0.0346 (4)
C11	0.2118 (3)	0.91352 (13)	0.35052 (17)	0.0365 (5)
C12	0.3273 (4)	0.84598 (15)	0.2926 (2)	0.0548 (7)
H12A	0.4375	0.8336	0.3363	0.082*
H12B	0.3614	0.8689	0.2222	0.082*
H12C	0.2570	0.7923	0.2823	0.082*
C13	−0.1434 (3)	0.76671 (17)	0.4117 (2)	0.0527 (6)
H13A	−0.2002	0.8200	0.4381	0.079*
H13B	−0.2273	0.7177	0.4194	0.079*
H13C	−0.1148	0.7739	0.3355	0.079*
C14	0.2499 (4)	0.55426 (17)	0.6339 (3)	0.0686 (8)
H14A	0.1340	0.5228	0.6335	0.103*
H14B	0.2977	0.5594	0.7083	0.103*
H14C	0.3372	0.5224	0.5905	0.103*
C15	0.4628 (4)	0.87030 (17)	0.5855 (2)	0.0605 (7)
H15A	0.5620	0.8471	0.6315	0.091*
H15B	0.4020	0.9175	0.6235	0.091*
H15C	0.5122	0.8927	0.5184	0.091*
N1	0.0570 (2)	1.04990 (10)	0.36059 (13)	0.0332 (4)
N2	0.1386 (2)	0.89975 (10)	0.44626 (13)	0.0330 (4)
Ni1	0.0000	1.0000	0.5000	0.02970 (12)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0378 (11)	0.0256 (9)	0.0300 (9)	0.0059 (8)	0.0070 (8)	−0.0003 (7)
C2	0.0395 (11)	0.0373 (11)	0.0384 (11)	0.0017 (9)	0.0029 (9)	−0.0047 (9)
C3	0.0424 (12)	0.0450 (13)	0.0392 (12)	0.0126 (10)	−0.0016 (9)	0.0039 (10)
C4	0.0540 (14)	0.0343 (11)	0.0380 (11)	0.0116 (10)	0.0077 (10)	0.0047 (9)
C5	0.0454 (12)	0.0303 (10)	0.0388 (11)	−0.0014 (9)	0.0072 (9)	−0.0003 (8)
C6	0.0387 (11)	0.0325 (10)	0.0314 (10)	0.0038 (8)	0.0062 (8)	−0.0004 (8)
C7	0.0581 (14)	0.0302 (10)	0.0359 (11)	0.0055 (9)	0.0098 (10)	0.0031 (8)
C8	0.0636 (15)	0.0322 (11)	0.0341 (11)	−0.0020 (10)	0.0123 (10)	0.0058 (9)
C9	0.0540 (13)	0.0371 (11)	0.0352 (11)	−0.0015 (10)	0.0173 (10)	−0.0007 (9)
C10	0.0401 (11)	0.0309 (10)	0.0333 (10)	0.0020 (9)	0.0114 (8)	0.0006 (8)
C11	0.0406 (12)	0.0326 (10)	0.0369 (11)	0.0036 (9)	0.0119 (9)	−0.0011 (9)
C12	0.0717 (17)	0.0424 (13)	0.0518 (14)	0.0173 (12)	0.0287 (13)	0.0052 (11)
C13	0.0467 (14)	0.0550 (15)	0.0556 (15)	−0.0001 (11)	−0.0098 (11)	0.0070 (12)
C14	0.080 (2)	0.0443 (15)	0.081 (2)	0.0118 (13)	0.0019 (16)	0.0215 (14)
C15	0.0502 (15)	0.0569 (16)	0.0737 (19)	−0.0089 (12)	−0.0079 (13)	−0.0072 (13)
N1	0.0415 (9)	0.0280 (8)	0.0307 (8)	0.0034 (7)	0.0098 (7)	0.0020 (7)
N2	0.0402 (9)	0.0263 (8)	0.0328 (9)	0.0035 (7)	0.0075 (7)	0.0016 (7)
Ni1	0.0379 (2)	0.02358 (18)	0.02805 (19)	0.00279 (14)	0.00890 (13)	0.00134 (14)

Geometric parameters (Å, º)

C1—C2	1.388 (3)	C10—C11	1.399 (3)
C1—C6	1.391 (3)	C11—N2	1.307 (2)
C1—N2	1.433 (2)	C11—C12	1.501 (3)
C2—C3	1.391 (3)	C12—H12A	0.9600
C2—C15	1.506 (3)	C12—H12B	0.9600
C3—C4	1.384 (3)	C12—H12C	0.9600
C3—H3	0.9300	C13—H13A	0.9600
C4—C5	1.376 (3)	C13—H13B	0.9600
C4—C14	1.511 (3)	C13—H13C	0.9600
C5—C6	1.389 (3)	C14—H14A	0.9600
C5—H5	0.9300	C14—H14B	0.9600
C6—C13	1.496 (3)	C14—H14C	0.9600
C7—N1	1.351 (2)	C15—H15A	0.9600
C7—C8	1.387 (3)	C15—H15B	0.9600
C7—H7	0.9300	C15—H15C	0.9600
C8—C9	1.371 (3)	N1—Ni1	1.9072 (15)
C8—H8	0.9300	N2—Ni1	1.9330 (15)
C9—C10	1.387 (3)	Ni1—N1^i	1.9072 (16)
C9—H9	0.9300	Ni1—N2^i	1.9330 (15)
C10—N1	1.375 (2)
C2—C1—C6	121.48 (18)	H12A—C12—H12B	109.5
C2—C1—N2	119.61 (18)	C11—C12—H12C	109.5
C6—C1—N2	118.92 (18)	H12A—C12—H12C	109.5
C1—C2—C3	118.0 (2)	H12B—C12—H12C	109.5
C1—C2—C15	121.2 (2)	C6—C13—H13A	109.5
C3—C2—C15	120.7 (2)	C6—C13—H13B	109.5
C4—C3—C2	122.2 (2)	H13A—C13—H13B	109.5
C4—C3—H3	118.9	C6—C13—H13C	109.5
C2—C3—H3	118.9	H13A—C13—H13C	109.5
C5—C4—C3	117.91 (19)	H13B—C13—H13C	109.5
C5—C4—C14	120.9 (2)	C4—C14—H14A	109.5
C3—C4—C14	121.2 (2)	C4—C14—H14B	109.5
C4—C5—C6	122.4 (2)	H14A—C14—H14B	109.5
C4—C5—H5	118.8	C4—C14—H14C	109.5
C6—C5—H5	118.8	H14A—C14—H14C	109.5
C5—C6—C1	118.0 (2)	H14B—C14—H14C	109.5
C5—C6—C13	120.1 (2)	C2—C15—H15A	109.5
C1—C6—C13	121.90 (19)	C2—C15—H15B	109.5
N1—C7—C8	110.75 (18)	H15A—C15—H15B	109.5
N1—C7—H7	124.6	C2—C15—H15C	109.5
C8—C7—H7	124.6	H15A—C15—H15C	109.5
C9—C8—C7	107.11 (18)	H15B—C15—H15C	109.5
C9—C8—H8	126.4	C7—N1—C10	105.35 (16)
C7—C8—H8	126.4	C7—N1—Ni1	142.51 (14)
C8—C9—C10	106.29 (18)	C10—N1—Ni1	112.13 (13)
C8—C9—H9	126.9	C11—N2—Ni1	113.71 (13)
C10—C9—H9	126.9	C1—N2—Ni1	128.98 (12)
N1—C10—C9	110.49 (18)	N1—Ni1—N1^i	180.00 (9)
N1—C10—C11	115.09 (17)	N1—Ni1—N2^i	96.82 (6)
C9—C10—C11	134.26 (19)	N1^i—Ni1—N2^i	83.18 (6)
N2—C11—C10	115.67 (17)	N1—Ni1—N2	83.18 (6)
N2—C11—C12	123.54 (19)	N1^i—Ni1—N2	96.82 (6)
C10—C11—C12	120.75 (18)	N2^i—Ni1—N2	180.000 (1)
C11—C12—H12A	109.5	C11—N2—C1	117.28 (16)
C11—C12—H12B	109.5
C6—C1—C2—C3	1.9 (3)	C9—C10—C11—C12	2.5 (4)
N2—C1—C2—C3	−177.96 (18)	C8—C7—N1—C10	−0.1 (3)
C6—C1—C2—C15	−175.2 (2)	C8—C7—N1—Ni1	−178.66 (18)
N2—C1—C2—C15	4.9 (3)	C9—C10—N1—C7	0.7 (2)
C1—C2—C3—C4	−1.4 (3)	C11—C10—N1—C7	−175.4 (2)
C15—C2—C3—C4	175.7 (2)	C9—C10—N1—Ni1	179.74 (15)
C2—C3—C4—C5	−0.1 (3)	C11—C10—N1—Ni1	3.7 (2)
C2—C3—C4—C14	−180.0 (2)	C10—C11—N2—C1	175.27 (18)
C3—C4—C5—C6	1.1 (3)	C12—C11—N2—C1	−2.4 (3)
C14—C4—C5—C6	−179.0 (2)	C10—C11—N2—Ni1	−3.1 (2)
C4—C5—C6—C1	−0.6 (3)	C12—C11—N2—Ni1	179.26 (18)
C4—C5—C6—C13	−179.6 (2)	C2—C1—N2—C11	86.3 (2)
C2—C1—C6—C5	−1.0 (3)	C6—C1—N2—C11	−93.6 (2)
N2—C1—C6—C5	178.95 (17)	C2—C1—N2—Ni1	−95.6 (2)
C2—C1—C6—C13	178.0 (2)	C6—C1—N2—Ni1	84.5 (2)
N2—C1—C6—C13	−2.1 (3)	C7—N1—Ni1—N2^i	−5.6 (3)
N1—C7—C8—C9	−0.5 (3)	C10—N1—Ni1—N2^i	175.89 (14)
C7—C8—C9—C10	0.9 (3)	C7—N1—Ni1—N2	174.4 (3)
C8—C9—C10—N1	−1.0 (3)	C10—N1—Ni1—N2	−4.11 (14)
C8—C9—C10—C11	174.0 (3)	C11—N2—Ni1—N1	4.03 (15)
N1—C10—C11—N2	−0.4 (3)	C1—N2—Ni1—N1	−174.07 (18)
C9—C10—C11—N2	−175.3 (2)	C11—N2—Ni1—N1^i	−175.97 (15)
N1—C10—C11—C12	177.3 (2)	C1—N2—Ni1—N1^i	5.93 (18)

Symmetry code: (i) −x, −y+2, −z+1.

Hydrogen-bond geometry (Å, º)

Cg1 is the centroid of the C1–C6 ring.

D—H···A	D—H	H···A	D···A	D—H···A
C7—H7···Cg1^ii	0.93	2.55	3.394 (4)	151
C8—H8···Cg1^iii	0.93	2.88	3.692 (9)	147

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