[Bis(3,5-dimethyl­pyrazol-1-yl-κN²)hydro­(pyrazol-1-yl-κN²)borato][(3,5-dimethyl­pyrazol-1-yl-κN²)dihydro(pyrazol-1-yl-κN²)borato]nickel(II)

The title compound, [Ni(C₈H₁₂BN₄)(C₁₃H₁₈BN₆)] or Bp′Tp′Ni^II, where Bp′ is (3,5-dimethyl­pyrazol-1-yl)dihydro(pyrazol-1-yl)borate and Tp′ is bis­(3,5-dimethyl­pyrazol-1-yl)hydro­(pyrazol-1-yl)borate, contains a divalent Ni^II centre bound by the chelating N atoms of the polysubstituted pyrazolylborate ligands. It is shown to lack a strong agostic B—H...Ni inter­action, implying that the sixth coordination site is unoccupied in the solid state. This square-pyramidal complex is the only known crystal structure where the Ni^II centre is penta­coordinated while bonded exclusively to pyrazolyl units. This is of inter­est with respect to electrochemical and catalytic properties.

S1. Comment

Polypyrazolyl borate ligands, also known as scorpionate ligands, are a unique class of ligands that have been extensively studied, in part because they are known to adopt multiple bonding configurations. The most common ones are the bidentate κ²-N,N' and the tridentate κ³-N,N',N'' types, while κ¹-N, κ²-H,N and κ³-H,N,N' are also known (Belderraín et al., 2002). Our interest in this class of compounds lies in the change in coordination geometry that can be induced through oxidation of the central ion (Connelly et al., 2001; Geiger et al., 2003). Specifically, this structural change may be exploited to modify the potential difference between subsequent oxidation states, thereby in theory yielding access to the coveted two-electron transfer. The nomenclature adopted here is as recommended by Trofimenko (1999). Thus, bis- and tris(homopyrazolyl)borate ligands are represented by the abbreviation Bp and Tp, respectively. The 3- and 5-alkyl substituents located on the pyrazolyl rings are listed in this order as superscripts, unless otherwise specified {e.g. Bp^4CN = [H₂B(4-cyanopyrazolyl)₂]^-}. In addition, the abbreviations py = pyrazolyl, dmpz = 3,5-dimethylpyrazolyl and dppz = 3,5-diphenylpyrazolyl are used.

The title compound, (I) (Fig. 1), was isolated while attempting to prepare the Tp''₂Ni scorpionate complex, where Tp'' is [(3,5-dimethylpyrazolyl)(pyrazolyl)₂BH]^-. Compound (I), generated in situ alongside the known orange-coloured Bp'₂Ni^II complex (Frauendorfer & Agrifoglio, 1982), consists of a pentahedral Ni^II centre bound by the five pyrazolyl moieties of the combined Bp' and Tp' ligands. The mechanism driving the in situ rearrangement of Tp'' to form the Bp' and Tp' ligands in the presence of nickel is still under investigation. Hence, it will not be considered here.

A survey of the literature revealed (I) to be the only structurally characterized example of a mixed Bp–Tp-type nickel complex. However, analogue cobalt(II) complexes have been shown to adopt either a pentahedral {e.g. [Tp^CHPh2][Ph₂Bp]Co (Rheingold et al., 2004), [Tp^i-Pr,4Br][Ph₂Bp]Co (Calabrese et al., 1990) and [Bp^4CN][Tp^Np]Co (Rheingold et al., 2000)} or an octahedral {e.g. [Tp^CHPh2][Bp^Ph]Co (Rheingold et al., 2004), [Tp^i-Pr,4Br][Bp^Ph]Co (Calabrese et al., 1990), [Bp^Ph,Ph][HB(3,5-dmpz)₂(3,5-dppz)]Co (Ruman et al., 2001) and [Bp^Ph,Ph][HB(3,5-dppz)₂(3,5-dmpz)]Co (Ruman et al., 2002)} geometry, depending on their ability to form a κ³-N,N,H agostic interaction. Exceptionally, [Bp^4CN][Tp^Cy]Co is pentahedral in solution, but octahedral when crystallized from a dimethylformamide solution (Rheingold et al., 2000). Moreover, Jezorek & McCurdy (1975) found that octahedral [Bp₃Ni]^- could be isolated from solutions kept meticulously anhydrous, whereas any exposure to moisture reverts the complex to the common Bp₂Ni form that contains no metal-coordinated water. Combined, these results illustrate the delicate energy differences that exists between the different coordination modes of Bp- and Tp-type ligands. In turn, it is the possibility of controlling this energy by judicious choice of ligand geometry that makes this class of compounds ideal for the design of redox-dependent coordination geometries. To this end, the detailed geometry of (I) is crucial.

The shortest Ni—N bond length (Table 1) of (I) was found to be the apical dmpz moiety of the Tp' ligand (i.e. Ni1—N6), whereas the other Ni—N bonds, which define the square plane, are of similar length (~2.06 Å) within the range of experimental error (3σ). These values are slightly shorter than the Ni—N bonds found in the octahedral Tp₂Ni^II complex [2.087 (2)–2.104 (3) Å (Bandoli et al., 1979)], but considerably longer than the Ni—N bonds of the square planar trans-Bp'₂Ni^II complex [1.894 (2) and 1.883 (3) Å (Kokusen et al., 1996)]. This suggests an important steric/electronic effect by the apical dmpz unit in (I). In addition, the Ni^II ion is found to be ~0.2 Å above the square plane defined by atoms N2, N4, N8 and N10, indicating an attraction to the apical dmpz moiety.

Determining whether or not an agostic B—H···Ni bond is present in (I) is important, since the absence of such implies that one coordination site remains open for reaction. Belderraín et al. (2002) found that the length of the B—H bond of Ni[Bp^t-Bu]₂ implicated in the agostic interaction [1.26 (5) Å] is slightly longer than that of the uncoordinated B—H bond [1.15 (5) Å]. A similar length differential is observed between bonds B2—H2A and B2—H2B of (I) (Table 1). However, the (B)H···Ni distance in (I) is 2.59 Å, considerably longer than those found in complexes with confirmed agostic-type interactions, e.g. [Ni(NCBH₃)₂(2,2',2''-triaminotriethylamine)]₂²⁺ [2.145 (26) Å (Segal & Lippard, 2002)] and Ni[Bp^t-Bu]₂ [1.86 (5) Å (Belderraín et al., 2002]. To examine this effect further, the B···Ni distance is analysed. This distance is an indirect measure of the agostic interaction, since H···Ni bonding requires the approach of the BH unit to the central Ni atom, thereby inducing strain in the N—Ni bond due to the rigid nature of the pyrazolyl unit. Comparison of the B···Ni distance in (I) (3.00 Å) with that observed in compounds exhibiting and devoid of agostic interactions, e.g. Ni[Bp^t-Bu]₂ (2.54 Å) (Belderraín et al., 2002) and Bp'₂Ni (3.05 Å) (Kokusen et al., 1996), respectively, suggests that the (B)H···Ni bond is very weak or possibly absent in (I).

The encapsulation of the metal ion by ligands provides it with the steric restraint to avoid unwanted dissociation, substitution and dimerization reactions often seen during redox and/or catalytic cycling. Conversely, a totally impenetrable capsule renders the central ion chemically inert. A quantitative measure by which to compare the degree of enclosure of different coordination and organotransition metal complexes is the wedge angle (Bondi, 1964). This defines the unoccupied space around the metal core accessible to an approaching solvent or substrate molecule and takes into account the van der Waals radii of the selected atoms. An appropriate measure is to determine both the widest and the narrowest wedge angles. The former, the wedge angle between the Tp'-bound B atom, the Ni core and the closest Bp'-bound H atom (i.e. B1—Ni1—H2B), is 87°. The latter, the wedge angle between the 3'-Me group of the Tp'-bound pyrazolyl ligand, the Ni core and the 3'-H atom of the adjacent unsubstituted Tp'-bound pyrazolyl ligand (i.e. H1C—Ni1—H6), is 68°. To provide a base for comparison, the related wedge angles of the trans-Bp'₂Ni^II complex (Kokusen et al., 1996) were calculated to 112 and 59°, respectively. Note that in the latter case these wedge angles can be measured from both top and bottom hemispheres.

The wedge angle is of further importance here, as the introduction of a highly nucleophilic ligand opposite the apical dmpz unit should weaken the Ni1—N6 bond, as is the case in the classical Tp₂Ni complex. In the extreme case, where this ligand addition leads to cleavage of the Ni1—N6 bond, a pendent pyrazolyl unit is formed. Upon oxidation, this unit will be prone to (re)coordination with the central Ni^II ion. The addition of a ligand in the vacant sixth coordination site would therefore be a route towards complexes that exhibit redox-dependent coordination geometry. This approach is currently under study in our laboratory.

In summary, our study reports the geometric parameters of the first pentahedral mixed Bp'–Tp' nickel coordination complex. We find no evidence for a strong agostic B—H···Ni interaction, hence conserving a free coordination site in the solid state despite the absence of large substituents on the pyrazolyl units. A measure of the wedge angles indicates that, similar to Bp₂Ni-type complexes but to a lesser degree, the Ni core is exposed. This offers a lead for further modification of this class of complexes.

S2. Experimental

The NaTp'' complex was synthesized in a stepwise fashion by the condensation of an equimolar amount of 3,5-dimethylpyrazole with pure NaBp in refluxing anisole. The progress of the reaction was monitored by measuring the volume of dihydrogen gas that was evolved. Once completed, the product was used for complexation without further purification.

The dropwise addition of a lime-green aqueous solution (10 ml) of NiCl₂(H₂O)₆ (0.357 g, 1.50 mmol) to a stirred colourless heterogeneous solution composed of H₂O (10 ml), dichloromethane (20 ml) and NaTp'' complex (0.792 g, 3.00 mmol) resulted in the formation of a red mixture. Following 10 min of further stirring, the organic phase was isolated and the aqueous phase was washed with three portions of dichloromethane (10 ml). The combined organic extracts were dried over MgSO₄, filtered and slowly concentrated under reduced pressure. During this time, an orange precipitate gradually appeared and the resulting mother liquor progressively turned a pale-violet colour. Filtration and complete evaporation of the solvent produced a violet crystalline solid. This crude material was further purified from the orange Bp'₂Ni^II by-product by flash chromatography using silica gel and an eluent mixture of 10% ethyl acetate in hexanes. Nevertheless, ¹H NMR and liquid chromatography–high-resolution mass spectroscopy suggested that more than one species was present in the isolated band. Pale-pink (almost colourless) crystals of (I) were obtained by allowing a dichloromethane solution of the violet product to evaporate slowly (ca 3 d) at ambient temperature.

S3. Refinement

H atoms bonded to C atoms were treated as riding, with C—H = 0.93–0.97 Å, and with U_iso(H) = kU_eq(C), where k = 1.5 for the methyl groups, which were permitted to rotate but not to tilt, and 1.2 otherwise. The coordinates of the H atoms bonded to B atoms were refined freely, with U_iso(H) = 1.2U_eq(B), giving B—H distances in the range 1.10 (3)–1.26 (3) Å. A slightly unusual orientation was observed for the displacement ellipsoids along the C15–C16 bond. This effect diminishes at lower temperature. The displacement parameter U_eq takes the values 0.069, 0.070 and 0.068 Ų for atoms C14, C15 and C16, respectively. Since all of these atoms are part of a preformed pyrazolyl unit, an incorrect atom assignment seems improbable.

Computing details

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: UdMX (Maris, 2004).

Figures

Fig. 1. The molecular structure of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. Carbon-bound H atoms have been omitted for clarity.

[Bis(3,5-dimethylpyrazol-1-yl-κN²)hydro(pyrazol-1-yl- κN²)borato][(3,5-dimethylpyrazol-1-yl-κN²)dihydro(pyrazol- 1-yl-κN²)borato]nickel(II)

Crystal data

[Ni(C8H12BN4)(C13H18BN6)]	F(000) = 1056
Mr = 502.86	Dx = 1.330 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: -P 2ybc	Cell parameters from 9026 reflections
a = 15.1899 (3) Å	θ = 3.0–62.6°
b = 9.8327 (2) Å	µ = 1.35 mm^−1
c = 17.1131 (4) Å	T = 298 K
β = 100.780 (1)°	Block, pale pink
V = 2510.87 (9) Å^3	0.30 × 0.10 × 0.05 mm
Z = 4

Data collection

Bruker Microstar diffractometer	4574 independent reflections
Radiation source: Rotating anode	3344 reflections with I > 2σ(I)
Helios optics monochromator	Rint = 0.063
Detector resolution: 8.3 pixels mm^-1	θmax = 68.1°, θmin = 3.0°
ω scans	h = −18→18
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −11→11
Tmin = 0.758, Tmax = 0.935	l = −20→20
41333 measured reflections

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)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.142	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0976P)^2] where P = (Fo^2 + 2Fc^2)/3
4574 reflections	(Δ/σ)max = 0.001
322 parameters	Δρmax = 0.53 e Å^−3
0 restraints	Δρmin = −0.23 e Å^−3

Special details

Experimental. X-ray crystallographic data for I were collected from a single-crystal sample, which was mounted on a loop fiber. Data were collected using a Bruker microstar diffractometer equiped with a Platinum 135 CCD Detector, a Helios optics and a Kappa goniometer. The crystal-to-detector distance was 4.0 cm, and the data collection was carried out in 512 x 512 pixel mode. The initial unit-cell parameters were determined by a least-squares fit of the angular setting of strong reflections, collected by a 10.0 degree scan in 33 frames over three different parts of the reciprocal space (99 frames total).

Geometry. All e.s.d.'s (except the e.s.d.'s 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
Ni1	0.24497 (3)	0.07922 (4)	0.52931 (2)	0.05256 (17)
N1	0.08558 (13)	0.1717 (2)	0.41746 (12)	0.0555 (5)
N2	0.12208 (13)	0.0563 (2)	0.45630 (12)	0.0549 (5)
N3	0.14441 (14)	0.3331 (2)	0.52913 (12)	0.0576 (5)
N4	0.19163 (13)	0.2426 (2)	0.58012 (12)	0.0569 (5)
N5	0.22530 (14)	0.3036 (2)	0.41580 (11)	0.0560 (5)
N6	0.28772 (14)	0.2117 (2)	0.45279 (11)	0.0560 (5)
N7	0.37186 (14)	−0.0401 (2)	0.66030 (12)	0.0602 (5)
N8	0.35415 (16)	0.0798 (2)	0.62188 (13)	0.0633 (6)
N9	0.31458 (14)	−0.1993 (2)	0.54855 (13)	0.0615 (6)
N10	0.28944 (15)	−0.1023 (2)	0.49110 (12)	0.0591 (5)
B1	0.1317 (2)	0.3092 (3)	0.43856 (18)	0.0587 (7)
H1	0.094 (2)	0.398 (3)	0.4114 (17)	0.070*
B2	0.3069 (2)	−0.1588 (4)	0.6351 (2)	0.0697 (9)
H2A	0.231 (2)	−0.105 (3)	0.6332 (18)	0.084*
H2B	0.3191 (19)	−0.251 (3)	0.6750 (18)	0.084*
C1	0.0846 (2)	−0.1882 (3)	0.45915 (19)	0.0746 (8)
H1A	0.1199	−0.2356	0.4268	0.112*
H1B	0.0284	−0.2342	0.4567	0.112*
H1C	0.1163	−0.1860	0.5132	0.112*
C2	0.06792 (17)	−0.0467 (3)	0.42924 (15)	0.0583 (6)
C3	−0.00271 (18)	0.0008 (3)	0.37230 (16)	0.0655 (7)
H3	−0.0496	−0.0506	0.3442	0.079*
C4	0.00959 (17)	0.1365 (3)	0.36536 (15)	0.0643 (7)
C5	−0.0457 (2)	0.2398 (3)	0.31308 (19)	0.0831 (9)
H5A	−0.0694	0.3048	0.3456	0.125*
H5B	−0.0942	0.1949	0.2787	0.125*
H5C	−0.0089	0.2858	0.2816	0.125*
C6	0.19428 (19)	0.2913 (3)	0.65333 (15)	0.0679 (7)
H6	0.2224	0.2486	0.6999	0.082*
C7	0.1496 (2)	0.4136 (3)	0.65032 (19)	0.0814 (9)
H7	0.1418	0.4685	0.6928	0.098*
C8	0.1189 (2)	0.4368 (3)	0.57024 (18)	0.0715 (8)
H8	0.0860	0.5120	0.5486	0.086*
C9	0.44194 (19)	0.1474 (3)	0.44964 (18)	0.0763 (8)
H9A	0.4797	0.1932	0.4930	0.114*
H9B	0.4738	0.1359	0.4066	0.114*
H9C	0.4253	0.0599	0.4671	0.114*
C10	0.36156 (17)	0.2281 (3)	0.42263 (14)	0.0594 (7)
C11	0.3455 (2)	0.3294 (3)	0.36446 (15)	0.0674 (8)
H11	0.3856	0.3606	0.3336	0.081*
C12	0.25966 (19)	0.3742 (3)	0.36133 (14)	0.0626 (7)
C13	0.2064 (2)	0.4813 (3)	0.31058 (18)	0.0824 (9)
H13A	0.2404	0.5153	0.2728	0.124*
H13B	0.1933	0.5546	0.3437	0.124*
H13C	0.1514	0.4426	0.2828	0.124*
C14	0.4214 (2)	0.1650 (3)	0.65009 (16)	0.0706 (8)
H14	0.4257	0.2544	0.6335	0.085*
C15	0.4832 (2)	0.1005 (3)	0.70748 (17)	0.0697 (8)
H15	0.5359	0.1364	0.7367	0.084*
C16	0.45037 (19)	−0.0266 (4)	0.71173 (15)	0.0689 (8)
H16	0.4779	−0.0948	0.7453	0.083*
C17	0.2752 (2)	−0.0824 (3)	0.34507 (17)	0.0809 (9)
H17A	0.2253	−0.0238	0.3475	0.121*
H17B	0.2590	−0.1461	0.3023	0.121*
H17C	0.3253	−0.0289	0.3361	0.121*
C18	0.30025 (18)	−0.1577 (3)	0.42169 (16)	0.0646 (7)
C19	0.33355 (18)	−0.2881 (3)	0.43566 (18)	0.0714 (8)
H19	0.3482	−0.3479	0.3980	0.086*
C20	0.34091 (18)	−0.3128 (3)	0.51550 (18)	0.0677 (7)
C21	0.3716 (2)	−0.4371 (3)	0.5623 (2)	0.0913 (10)
H21A	0.4259	−0.4175	0.5992	0.137*
H21B	0.3825	−0.5083	0.5269	0.137*
H21C	0.3262	−0.4657	0.5910	0.137*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0439 (3)	0.0702 (3)	0.0420 (2)	0.00233 (18)	0.00402 (18)	0.00118 (17)
N1	0.0416 (11)	0.0718 (13)	0.0495 (11)	−0.0009 (9)	−0.0013 (9)	−0.0049 (10)
N2	0.0444 (12)	0.0673 (13)	0.0510 (11)	−0.0004 (9)	0.0039 (9)	−0.0010 (9)
N3	0.0460 (12)	0.0714 (13)	0.0515 (11)	0.0009 (10)	−0.0007 (9)	−0.0049 (10)
N4	0.0484 (12)	0.0727 (13)	0.0470 (11)	0.0019 (10)	0.0024 (9)	0.0002 (10)
N5	0.0500 (12)	0.0703 (13)	0.0435 (10)	−0.0044 (10)	−0.0021 (9)	0.0029 (9)
N6	0.0420 (11)	0.0766 (14)	0.0474 (11)	−0.0021 (10)	0.0035 (9)	0.0000 (10)
N7	0.0548 (13)	0.0783 (14)	0.0463 (11)	0.0105 (11)	0.0067 (10)	−0.0004 (10)
N8	0.0627 (14)	0.0764 (15)	0.0479 (12)	0.0103 (11)	0.0028 (10)	0.0022 (10)
N9	0.0499 (12)	0.0755 (14)	0.0572 (12)	0.0077 (10)	0.0049 (10)	−0.0020 (11)
N10	0.0487 (12)	0.0783 (14)	0.0497 (12)	0.0020 (10)	0.0078 (9)	−0.0022 (10)
B1	0.0454 (16)	0.0746 (19)	0.0514 (16)	0.0007 (14)	−0.0029 (13)	0.0022 (14)
B2	0.067 (2)	0.085 (2)	0.0574 (18)	0.0103 (17)	0.0139 (15)	0.0055 (16)
C1	0.0696 (19)	0.0793 (19)	0.0761 (19)	−0.0104 (15)	0.0170 (15)	−0.0036 (15)
C2	0.0468 (14)	0.0746 (17)	0.0542 (14)	−0.0065 (12)	0.0118 (12)	−0.0080 (12)
C3	0.0487 (15)	0.0821 (19)	0.0626 (16)	−0.0094 (13)	0.0028 (12)	−0.0144 (14)
C4	0.0455 (15)	0.091 (2)	0.0516 (14)	0.0011 (14)	−0.0025 (12)	−0.0086 (14)
C5	0.0649 (19)	0.099 (2)	0.0735 (18)	0.0017 (16)	−0.0182 (15)	−0.0063 (17)
C6	0.0669 (18)	0.088 (2)	0.0468 (14)	0.0038 (15)	0.0046 (12)	−0.0071 (13)
C7	0.083 (2)	0.096 (2)	0.0606 (17)	0.0157 (17)	0.0008 (15)	−0.0211 (15)
C8	0.0638 (18)	0.0741 (18)	0.0706 (18)	0.0116 (14)	−0.0027 (14)	−0.0130 (14)
C9	0.0543 (17)	0.103 (2)	0.0735 (19)	0.0001 (16)	0.0168 (14)	−0.0111 (17)
C10	0.0445 (14)	0.0846 (18)	0.0490 (13)	−0.0084 (12)	0.0084 (11)	−0.0089 (12)
C11	0.0654 (18)	0.092 (2)	0.0460 (14)	−0.0211 (15)	0.0134 (12)	−0.0027 (13)
C12	0.0636 (18)	0.0790 (17)	0.0407 (13)	−0.0145 (14)	−0.0016 (12)	0.0004 (12)
C13	0.084 (2)	0.094 (2)	0.0610 (17)	−0.0153 (18)	−0.0071 (15)	0.0126 (16)
C14	0.0656 (18)	0.0864 (19)	0.0539 (15)	−0.0054 (15)	−0.0041 (13)	−0.0081 (14)
C15	0.0582 (17)	0.089 (2)	0.0568 (16)	0.0028 (15)	−0.0022 (13)	−0.0087 (14)
C16	0.0567 (16)	0.101 (2)	0.0429 (13)	0.0251 (16)	−0.0050 (12)	−0.0054 (14)
C17	0.078 (2)	0.111 (3)	0.0535 (16)	−0.0101 (17)	0.0116 (15)	−0.0143 (15)
C18	0.0485 (15)	0.090 (2)	0.0541 (15)	−0.0086 (14)	0.0069 (12)	−0.0138 (13)
C19	0.0510 (16)	0.085 (2)	0.0769 (19)	−0.0004 (14)	0.0094 (14)	−0.0262 (16)
C20	0.0486 (15)	0.0746 (17)	0.0764 (19)	0.0008 (13)	0.0029 (13)	−0.0141 (15)
C21	0.079 (2)	0.083 (2)	0.104 (3)	0.0107 (17)	−0.002 (2)	−0.0099 (18)

Geometric parameters (Å, º)

Ni1—N2	2.055 (2)	C5—H5A	0.9600
Ni1—N4	2.063 (2)	C5—H5B	0.9600
Ni1—N6	2.038 (2)	C5—H5C	0.9600
Ni1—N8	2.068 (2)	C6—C7	1.378 (4)
Ni1—N10	2.058 (2)	C6—H6	0.9300
N1—C4	1.365 (3)	C7—C8	1.381 (4)
N1—N2	1.377 (3)	C7—H7	0.9300
N1—B1	1.534 (4)	C8—H8	0.9300
N2—C2	1.333 (3)	C9—C10	1.457 (4)
N3—C8	1.337 (4)	C9—H9A	0.9600
N3—N4	1.354 (3)	C9—H9B	0.9600
N3—B1	1.544 (4)	C9—H9C	0.9600
N4—C6	1.335 (3)	C10—C11	1.398 (4)
N5—C12	1.344 (3)	C11—C12	1.367 (4)
N5—N6	1.375 (3)	C11—H11	0.9300
N5—B1	1.544 (4)	C12—C13	1.502 (4)
N6—C10	1.329 (3)	C13—H13A	0.9600
N7—C16	1.350 (3)	C13—H13B	0.9600
N7—N8	1.352 (3)	C13—H13C	0.9600
N7—B2	1.538 (5)	C14—C15	1.380 (4)
N8—C14	1.339 (4)	C14—H14	0.9300
N9—C20	1.345 (3)	C15—C16	1.352 (4)
N9—N10	1.372 (3)	C15—H15	0.9300
N9—B2	1.559 (4)	C16—H16	0.9300
N10—C18	1.344 (3)	C17—C18	1.492 (4)
B1—H1	1.10 (3)	C17—H17A	0.9600
B2—H2A	1.26 (3)	C17—H17B	0.9600
B2—H2B	1.13 (3)	C17—H17C	0.9600
C1—C2	1.487 (4)	C18—C19	1.383 (4)
C1—H1A	0.9600	C19—C20	1.371 (4)
C1—H1B	0.9600	C19—H19	0.9300
C1—H1C	0.9600	C20—C21	1.488 (4)
C2—C3	1.389 (4)	C21—H21A	0.9600
C3—C4	1.355 (4)	C21—H21B	0.9600
C3—H3	0.9300	C21—H21C	0.9600
C4—C5	1.503 (4)
N2—Ni1—N4	87.58 (8)	C4—C5—H5A	109.5
N2—Ni1—N6	92.39 (8)	C4—C5—H5B	109.5
N2—Ni1—N8	166.66 (9)	H5A—C5—H5B	109.5
N2—Ni1—N10	91.53 (9)	C4—C5—H5C	109.5
N4—Ni1—N8	89.83 (8)	H5A—C5—H5C	109.5
N4—Ni1—N6	88.31 (9)	H5B—C5—H5C	109.5
N4—Ni1—N10	170.87 (9)	N4—C6—C7	110.5 (3)
N6—Ni1—N8	100.62 (9)	N4—C6—H6	124.8
N6—Ni1—N10	100.80 (9)	C7—C6—H6	124.8
N8—Ni1—N10	88.97 (9)	C6—C7—C8	104.7 (3)
C4—N1—N2	108.7 (2)	C6—C7—H7	127.6
C4—N1—B1	132.1 (2)	C8—C7—H7	127.6
N2—N1—B1	119.15 (19)	N3—C8—C7	108.6 (3)
C2—N2—N1	106.97 (19)	N3—C8—H8	125.7
C2—N2—Ni1	136.55 (17)	C7—C8—H8	125.7
N1—N2—Ni1	116.17 (14)	C10—C9—H9A	109.5
C8—N3—N4	109.5 (2)	C10—C9—H9B	109.5
C8—N3—B1	130.6 (2)	H9A—C9—H9B	109.5
N4—N3—B1	119.9 (2)	C10—C9—H9C	109.5
C6—N4—N3	106.8 (2)	H9A—C9—H9C	109.5
C6—N4—Ni1	136.86 (18)	H9B—C9—H9C	109.5
N3—N4—Ni1	116.26 (15)	N6—C10—C11	108.3 (2)
C12—N5—N6	109.6 (2)	N6—C10—C9	121.9 (3)
C12—N5—B1	130.7 (2)	C11—C10—C9	129.7 (3)
N6—N5—B1	119.7 (2)	C12—C11—C10	107.2 (2)
C10—N6—N5	107.5 (2)	C12—C11—H11	126.4
C10—N6—Ni1	136.06 (19)	C10—C11—H11	126.4
N5—N6—Ni1	116.14 (15)	N5—C12—C11	107.3 (2)
C16—N7—N8	107.6 (2)	N5—C12—C13	121.8 (3)
C16—N7—B2	134.5 (3)	C11—C12—C13	130.9 (3)
N8—N7—B2	117.8 (2)	C12—C13—H13A	109.5
C14—N8—N7	107.5 (2)	C12—C13—H13B	109.5
C14—N8—Ni1	136.55 (19)	H13A—C13—H13B	109.5
N7—N8—Ni1	115.36 (17)	C12—C13—H13C	109.5
C20—N9—N10	109.9 (2)	H13A—C13—H13C	109.5
C20—N9—B2	133.8 (3)	H13B—C13—H13C	109.5
N10—N9—B2	116.3 (2)	N8—C14—C15	109.9 (3)
C18—N10—N9	106.7 (2)	N8—C14—H14	125.0
C18—N10—Ni1	137.2 (2)	C15—C14—H14	125.0
N9—N10—Ni1	116.05 (16)	C16—C15—C14	104.7 (3)
N1—B1—N3	109.7 (2)	C16—C15—H15	127.7
N1—B1—N5	108.1 (2)	C14—C15—H15	127.7
N3—B1—N5	108.1 (2)	N7—C16—C15	110.2 (3)
N1—B1—H1	115.0 (15)	N7—C16—H16	124.9
N3—B1—H1	105.1 (15)	C15—C16—H16	124.9
N5—B1—H1	110.6 (16)	C18—C17—H17A	109.5
N7—B2—N9	107.6 (2)	C18—C17—H17B	109.5
N7—B2—H2A	103.0 (14)	H17A—C17—H17B	109.5
N9—B2—H2A	108.2 (14)	C18—C17—H17C	109.5
N7—B2—H2B	114.6 (15)	H17A—C17—H17C	109.5
N9—B2—H2B	109.6 (15)	H17B—C17—H17C	109.5
H2A—B2—H2B	113 (2)	N10—C18—C19	108.9 (3)
C2—C1—H1A	109.5	N10—C18—C17	121.5 (3)
C2—C1—H1B	109.5	C19—C18—C17	129.6 (3)
H1A—C1—H1B	109.5	C20—C19—C18	107.2 (3)
C2—C1—H1C	109.5	C20—C19—H19	126.4
H1A—C1—H1C	109.5	C18—C19—H19	126.4
H1B—C1—H1C	109.5	N9—C20—C19	107.3 (3)
N2—C2—C3	109.5 (2)	N9—C20—C21	122.9 (3)
N2—C2—C1	122.5 (2)	C19—C20—C21	129.8 (3)
C3—C2—C1	128.0 (3)	C20—C21—H21A	109.5
C4—C3—C2	107.0 (2)	C20—C21—H21B	109.5
C4—C3—H3	126.5	H21A—C21—H21B	109.5
C2—C3—H3	126.5	C20—C21—H21C	109.5
C3—C4—N1	107.8 (2)	H21A—C21—H21C	109.5
C3—C4—C5	130.3 (2)	H21B—C21—H21C	109.5
N1—C4—C5	121.9 (3)
C4—N1—N2—C2	−1.2 (3)	C8—N3—B1—N1	−125.2 (3)
B1—N1—N2—C2	177.8 (2)	N4—N3—B1—N1	58.0 (3)
C4—N1—N2—Ni1	173.46 (17)	C8—N3—B1—N5	117.1 (3)
B1—N1—N2—Ni1	−7.5 (3)	N4—N3—B1—N5	−59.6 (3)
N6—Ni1—N2—C2	134.6 (3)	C12—N5—B1—N1	115.4 (3)
N10—Ni1—N2—C2	33.8 (3)	N6—N5—B1—N1	−62.7 (3)
N4—Ni1—N2—C2	−137.1 (3)	C12—N5—B1—N3	−126.0 (3)
N8—Ni1—N2—C2	−58.2 (5)	N6—N5—B1—N3	56.0 (3)
N6—Ni1—N2—N1	−37.95 (17)	C16—N7—B2—N9	−108.8 (3)
N10—Ni1—N2—N1	−138.83 (17)	N8—N7—B2—N9	66.5 (3)
N4—Ni1—N2—N1	50.26 (17)	C20—N9—B2—N7	117.1 (3)
N8—Ni1—N2—N1	129.2 (4)	N10—N9—B2—N7	−63.4 (3)
C8—N3—N4—C6	0.5 (3)	N1—N2—C2—C3	0.8 (3)
B1—N3—N4—C6	177.8 (2)	Ni1—N2—C2—C3	−172.21 (19)
C8—N3—N4—Ni1	−176.24 (18)	N1—N2—C2—C1	−178.5 (2)
B1—N3—N4—Ni1	1.1 (3)	Ni1—N2—C2—C1	8.4 (4)
N6—Ni1—N4—C6	−129.8 (3)	N2—C2—C3—C4	−0.2 (3)
N2—Ni1—N4—C6	137.7 (3)	C1—C2—C3—C4	179.2 (3)
N8—Ni1—N4—C6	−29.2 (3)	C2—C3—C4—N1	−0.6 (3)
N6—Ni1—N4—N3	45.58 (17)	C2—C3—C4—C5	−180.0 (3)
N2—Ni1—N4—N3	−46.88 (17)	N2—N1—C4—C3	1.1 (3)
N8—Ni1—N4—N3	146.21 (18)	B1—N1—C4—C3	−177.7 (3)
C12—N5—N6—C10	1.6 (3)	N2—N1—C4—C5	−179.4 (3)
B1—N5—N6—C10	−180.0 (2)	B1—N1—C4—C5	1.7 (5)
C12—N5—N6—Ni1	−173.57 (16)	N3—N4—C6—C7	−0.4 (3)
B1—N5—N6—Ni1	4.9 (3)	Ni1—N4—C6—C7	175.3 (2)
N2—Ni1—N6—C10	−134.2 (2)	N4—C6—C7—C8	0.2 (4)
N10—Ni1—N6—C10	−42.2 (2)	N4—N3—C8—C7	−0.4 (3)
N4—Ni1—N6—C10	138.3 (2)	B1—N3—C8—C7	−177.3 (3)
N8—Ni1—N6—C10	48.7 (2)	C6—C7—C8—N3	0.1 (4)
N2—Ni1—N6—N5	39.10 (17)	N5—N6—C10—C11	−1.3 (3)
N10—Ni1—N6—N5	131.11 (16)	Ni1—N6—C10—C11	172.43 (18)
N4—Ni1—N6—N5	−48.40 (16)	N5—N6—C10—C9	179.2 (2)
N8—Ni1—N6—N5	−137.91 (16)	Ni1—N6—C10—C9	−7.1 (4)
C16—N7—N8—C14	−0.2 (3)	N6—C10—C11—C12	0.6 (3)
B2—N7—N8—C14	−176.6 (2)	C9—C10—C11—C12	−179.9 (3)
C16—N7—N8—Ni1	172.69 (17)	N6—N5—C12—C11	−1.2 (3)
B2—N7—N8—Ni1	−3.7 (3)	B1—N5—C12—C11	−179.4 (2)
N6—Ni1—N8—C14	24.5 (3)	N6—N5—C12—C13	179.3 (2)
N2—Ni1—N8—C14	−142.5 (4)	B1—N5—C12—C13	1.1 (4)
N10—Ni1—N8—C14	125.3 (3)	C10—C11—C12—N5	0.4 (3)
N4—Ni1—N8—C14	−63.8 (3)	C10—C11—C12—C13	179.8 (3)
N6—Ni1—N8—N7	−145.59 (18)	N7—N8—C14—C15	−0.2 (3)
N2—Ni1—N8—N7	47.5 (5)	Ni1—N8—C14—C15	−170.8 (2)
N10—Ni1—N8—N7	−44.80 (18)	N8—C14—C15—C16	0.4 (3)
N4—Ni1—N8—N7	126.16 (18)	N8—N7—C16—C15	0.4 (3)
C20—N9—N10—C18	0.2 (3)	B2—N7—C16—C15	176.0 (3)
B2—N9—N10—C18	−179.4 (2)	C14—C15—C16—N7	−0.5 (3)
C20—N9—N10—Ni1	179.18 (17)	N9—N10—C18—C19	−1.0 (3)
B2—N9—N10—Ni1	−0.5 (3)	Ni1—N10—C18—C19	−179.6 (2)
N6—Ni1—N10—C18	−34.1 (3)	N9—N10—C18—C17	177.2 (2)
N2—Ni1—N10—C18	58.6 (3)	Ni1—N10—C18—C17	−1.4 (4)
N8—Ni1—N10—C18	−134.7 (3)	N10—C18—C19—C20	1.4 (3)
N6—Ni1—N10—N9	147.40 (17)	C17—C18—C19—C20	−176.6 (3)
N2—Ni1—N10—N9	−119.88 (18)	N10—N9—C20—C19	0.6 (3)
N8—Ni1—N10—N9	46.78 (18)	B2—N9—C20—C19	−179.8 (3)
C4—N1—B1—N3	125.0 (3)	N10—N9—C20—C21	−179.5 (3)
N2—N1—B1—N3	−53.7 (3)	B2—N9—C20—C21	0.0 (5)
C4—N1—B1—N5	−117.4 (3)	C18—C19—C20—N9	−1.2 (3)
N2—N1—B1—N5	63.9 (3)	C18—C19—C20—C21	178.9 (3)