Crystal structure of trans-(1,8-dibutyl-1,3,6,8,10,13-hexa­aza­cyclo­tetra­decane-κ⁴N³,N⁶,N¹⁰,N¹³)bis­(5-methyltetra­zolato-κN)nickel(II) from synchrotron data

The Ni^II ion in the title compound shows a slightly distorted octa­hedral coordination geometry with four N atoms of the aza­macrocylic ligand and two N atoms of the 5-methyl-1H-tetra­zolate ions. In the crystal, mol­ecules are connected by an N—H...N hydrogen bond, forming a supra­molecular sheet structure.

Key indicators

• Single-crystal synchrotron study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.032
• wR factor = 0.090
• Data-to-parameter ratio = 23.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT220_ALERT_2_C Large Non-Solvent  C     Ueq(max)/Ueq(min) Range        3.5 Ratio
PLAT222_ALERT_3_C Large Non-Solvent  H     Uiso(max)/Uiso(min) ...        5.6 Ratio
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          2 Report
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          2 Note

Alert level G
ABSMU01_ALERT_1_G  Calculation of _exptl_absorpt_correction_mu
                not performed for this radiation type.
PLAT007_ALERT_5_G Number of Unrefined Donor-H Atoms ..............          2 Report
PLAT066_ALERT_1_G Predicted and Reported Tmin&Tmax Range Identical          ? Check
PLAT793_ALERT_4_G The Model has Chirality at N1      (Centro SPGR)          R Verify
PLAT793_ALERT_4_G The Model has Chirality at N2      (Centro SPGR)          S Verify
PLAT910_ALERT_3_G Missing # of FCF Reflection(s) Below Th(Min) ...          1 Report
PLAT984_ALERT_1_G The Ni-f'=     0.352 Deviates from the B&C-Value      0.339 Check

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   4 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   7 ALERT level G = General information/check it is not something unexpected

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

---

S1. Chemical context

Coordination compounds with macrocyclic ligands have been studied widely in chemistry, metalloenzymes and materials science (Lehn, 1995). In particular, Ni^II macrocyclic complexes having vacant sites in the axial positions are good building blocks for assembling supra­molecular frameworks (Min & Suh, 2001), with potential applications in gas adsorption/desorption (Lee & Suh, 2004), carbon dioxide reduction (Froehlich & Kubiak, 2012) and chiral separation (Ryoo et al., 2010). For example, Ni^II complexes with tetra-aza­macrocyclic ligands have been studied as catalysts for water oxidation at neutral pH (Zhang et al., 2014) and their magnetic properties have been investigated with various auxiliary anionic moieties such as azide, dicyanamide and ferricyanide (Yuan et al., 2011). Moreover, tetra­zole derivatives are versatile anions which can easily bridge to transition metal ions, thus allowing the assembly of multi-dimensional compounds (Zhao et al., 2008). Here, we report the synthesis and crystal structure of an Ni^II aza­macrocyclic complex with two tetra­zole derivatives, trans-(1,8-di­butyl-1,3,6,8,10,13-hexa­aza­cyclo­tetra­decane-κ⁴N³,N⁶,N¹⁰,N¹³)bis­(5- methyl­tetra­zolato-κN)nickel(II) (I).

S2. Structural commentary

In the title compound, the coordination environment around the Ni^II ion, in which the Ni^II ion lies on an inversion center, has a tetra­gonally distorted o­cta­hedral geometry. The Ni^II ion is bonded to four secondary N atoms of the aza­macrocyclic ligand in a square-planar fashion in the equatorial plane, and to two N atoms from the 5-methyl­tetra­zolate anions at the axial positions, as shown in Fig. 1. The average Ni—N_eq bond length and the Ni—N_ax length are 2.060 (2) and 2.2183 (11) Å, respectively. The axial bond lengths are much longer than the equatorial bond lengths, which can be attributed to a rather large Jahn–Teller distortion of the Ni^II ion and/or ring contraction of the aza­macrocyclic ligand (Halcrow, 2013). The six-membered chelate rings adopt chair conformations and the five-membered chelate rings assume gauche conformations (Min & Suh, 2001). The N—N bond lengths in the 5-methyl­tetra­zolate ion range from 1.3182 (15) to 1.3543 (16) Å, indicating that the tetra­zolate ring is fully delocalized. An intra­molecular N—H···N hydrogen bond between the secondary amine group of the macrocyclic ligand and the N atom of the 5-methyl­tetra­zolate ion stabilizes the molecular structure (Fig. 1 and Table 1).

S3. Supra­molecular features

The packing in the structure involves an inter­molecular N—H···N hydrogen bond between the secondary amine group of the macrocyclic ligand and the non-coordinating N atom of the 5-methyl­tetra­zolate ion (Table 1), which forms a rigid supra­molecular two-dimensional sheet structure parallel to the bc plane (Fig. 2).

S4. Database survey

A search of the Cambridge Structural Database (Version 5.35, May 2014 with 3 updates; Groom & Allen, 2014) indicated that 71 Ni^II aza­macrocyclic complexes with alkyl pendant groups have been reported. These complexes with various alkyl pendant groups were investigated as good building blocks for supra­molecular chemistry and also studied for their magnetic properties and gas sorption abilities due to the anions such as cyanido groups and carb­oxy­lic acid derivatives (Hyun et al., 2013; Shen et al., 2012). No corresponding Ni^II aza­macrocyclic complex with a butyl pendant group and tetra­zole derivatives has been reported, and the title compound was newly synthesized for this research.

S5. Synthesis and crystallization

The title compound (I) was prepared as follows. The starting complex, [Ni(C₁₆H₃₈N₆)(ClO₄)₂], was prepared by a slightly modification of the reported method (Jung et al., 1989). To an MeCN (10 ml) solution of [Ni(C₁₆H₃₈N₆)(ClO₄)₂] (0.10 g, 0.17 mmol) was slowly added an MeCN solution (5 ml) containing 5-methyl-1H-tetra­zole (0.029 g, 0.34 mmol) and excess tri­ethyl­amine (0.04 g, 0.40 mmol) at room temperature. The color of the solution turned from yellow to pale pink and a pale-pink precipitate was formed, which was filtered off, washed with MeCN, and di­ethyl ether, and dried in air. Single crystals of the title compound were obtained by layering of the MeCN solution of 5-methyl-1H-tetra­zole on the MeCN solution of [Ni(C₁₆H₃₈N₆)(ClO₄)₂] for several days. Yield: 0.057 g (62%). FT–IR (ATR, cm^-1): 3215, 2954, 1590, 1488, 1457, 1376, 1237, 1019, 933.

Safety note: Although we have experienced no problem with the compounds reported in this study, perchlorate salts of metal complexes are often explosive and should be handled with great caution.

S6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C—H = 0.98–0.99 Å and N—H = 1.00 Å, and with U_iso(H) values of 1.2 or 1.5U_eq of the parent atoms.

Related literature

For related literature, see: Froehlich & Kubiak (2012); Groom & Allen (2014); Halcrow (2013); Hyun, –M, Kim, Kim, Moon & Moon (2013); Jung et al. (1989); Lee & Suh (2004); Lehn (1995); Min & Suh (2001); Ryoo et al. (2010); Shen et al. (2012); Steed & Atwood (2009); Yuan, –H, Qian, –Y, Liu, –Y, Zhou & Song (2011); Zhang et al. (2014); Zhao et al. (2008).

Computing details

Data collection: PAL ADSC Quantum-210 ADX (Arvai & Nielsen, 1983); cell refinement: HKL3000sm (Otwinowski & Minor, 1997); data reduction: HKL3000sm (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXT2014/5 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014/7 (Sheldrick, 2008, 2015b); molecular graphics: DIAMOND4 (Putz & Brandenburg, 2014); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. View of the molecular structure of the title compound, showing the atom-labelling scheme, with displacement ellipsoids drawn at the 50% probability level. H atoms bonded to C atoms have been omitted for clarity. Intramolecular N—H···N hydrogen bonds are shown as green dashed lines. [Symmetry code: (i) -x + 1/2, -y + 3/2, -z + 1.]
	Fig. 2. View of the crystal packing of the title compound, with N—H···N hydrogen bonds drawn as green (intramolecular) and red (intermolecular) dashed lines.

trans-(1,8-Dibutyl-1,3,6,8,10,13-hexaazacyclotetradecane-κ⁴N³,N⁶,N¹⁰,N¹³)bis(5-methyltetrazolato-κN²)nickel(II)

Crystal data

[Ni(C2H3N4)2(C16H38N6)]	F(000) = 1160
Mr = 539.40	Dx = 1.339 Mg m^−3
Monoclinic, C2/c	Synchrotron radiation, λ = 0.62998 Å
a = 24.040 (5) Å	Cell parameters from 25946 reflections
b = 12.923 (3) Å	θ = 0.4–33.6°
c = 8.7170 (17) Å	µ = 0.55 mm^−1
β = 98.94 (3)°	T = 100 K
V = 2675.1 (9) Å^3	Block, pink
Z = 4	0.05 × 0.04 × 0.04 mm

Data collection

ADSC Q210 CCD area-detector diffractometer	3150 reflections with I > 2σ(I)
Radiation source: PLSII 2D bending magent	Rint = 0.042
ω scan	θmax = 26.0°, θmin = 1.6°
Absorption correction: empirical (using intensity measurements) (HKL3000sm SCALEPACK; Otwinowski & Minor, 1997)	h = −33→33
Tmin = 0.973, Tmax = 0.978	k = −17→17
12808 measured reflections	l = −12→12
3761 independent reflections

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) = 0.090	w = 1/[σ^2(Fo^2) + (0.0565P)^2 + 0.106P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max < 0.001
3761 reflections	Δρmax = 0.32 e Å^−3
162 parameters	Δρmin = −0.79 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.

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

	x	y	z	Uiso*/Ueq
Ni1	0.2500	0.7500	0.5000	0.00596 (8)
N1	0.31782 (5)	0.83411 (8)	0.60560 (11)	0.0073 (2)
H1	0.3488	0.7841	0.6424	0.009*
N2	0.28136 (5)	0.73476 (8)	0.29352 (12)	0.0076 (2)
H2	0.3095	0.6773	0.3067	0.009*
N3	0.35616 (5)	0.86428 (8)	0.36376 (12)	0.0095 (2)
C1	0.29951 (5)	0.88036 (9)	0.74420 (13)	0.0094 (2)
H1A	0.2752	0.9411	0.7137	0.011*
H1B	0.3327	0.9038	0.8177	0.011*
C2	0.34005 (6)	0.90993 (9)	0.50278 (14)	0.0097 (2)
H2A	0.3110	0.9634	0.4716	0.012*
H2B	0.3733	0.9448	0.5621	0.012*
C3	0.31026 (6)	0.82902 (9)	0.24815 (14)	0.0096 (2)
H3A	0.3251	0.8147	0.1505	0.011*
H3B	0.2823	0.8854	0.2270	0.011*
C4	0.23296 (6)	0.70064 (10)	0.17841 (14)	0.0095 (2)
H4A	0.2464	0.6706	0.0864	0.011*
H4B	0.2083	0.7603	0.1441	0.011*
C5	0.40350 (6)	0.79167 (10)	0.39114 (15)	0.0119 (2)
H5A	0.4070	0.7560	0.2926	0.014*
H5B	0.3955	0.7386	0.4666	0.014*
C6	0.45926 (6)	0.84385 (12)	0.45282 (18)	0.0188 (3)
H6A	0.4686	0.8939	0.3747	0.023*
H6B	0.4553	0.8829	0.5483	0.023*
C7	0.50699 (7)	0.76635 (13)	0.4891 (2)	0.0237 (3)
H7A	0.5101	0.7263	0.3940	0.028*
H7B	0.4977	0.7172	0.5685	0.028*
C8	0.56368 (7)	0.81669 (16)	0.5480 (2)	0.0334 (4)
H8A	0.5737	0.8641	0.4688	0.050*
H8B	0.5926	0.7630	0.5696	0.050*
H8C	0.5612	0.8554	0.6434	0.050*
N4	0.30074 (5)	0.61260 (8)	0.58628 (12)	0.0100 (2)
N5	0.29007 (5)	0.51298 (9)	0.56721 (14)	0.0156 (2)
N6	0.33266 (5)	0.45876 (9)	0.64836 (16)	0.0185 (3)
N7	0.35088 (5)	0.62585 (9)	0.67914 (13)	0.0146 (2)
C9	0.36869 (6)	0.52976 (10)	0.71493 (17)	0.0157 (3)
C10	0.42228 (7)	0.50538 (13)	0.8200 (2)	0.0298 (4)
H10A	0.4139	0.4869	0.9230	0.045*
H10B	0.4470	0.5661	0.8285	0.045*
H10C	0.4411	0.4472	0.7773	0.045*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.00867 (12)	0.00459 (12)	0.00474 (11)	−0.00101 (8)	0.00141 (8)	−0.00027 (7)
N1	0.0102 (5)	0.0052 (5)	0.0069 (4)	−0.0004 (4)	0.0021 (4)	−0.0002 (4)
N2	0.0092 (5)	0.0077 (5)	0.0061 (4)	−0.0007 (4)	0.0016 (4)	−0.0005 (4)
N3	0.0085 (5)	0.0105 (5)	0.0097 (5)	−0.0006 (4)	0.0024 (4)	0.0003 (4)
C1	0.0120 (6)	0.0083 (5)	0.0080 (5)	−0.0012 (4)	0.0016 (4)	−0.0031 (4)
C2	0.0114 (6)	0.0068 (5)	0.0115 (5)	−0.0016 (4)	0.0032 (4)	0.0001 (4)
C3	0.0112 (6)	0.0095 (6)	0.0084 (5)	−0.0012 (4)	0.0026 (4)	0.0022 (4)
C4	0.0112 (6)	0.0109 (6)	0.0062 (5)	0.0000 (5)	0.0012 (4)	−0.0009 (4)
C5	0.0099 (6)	0.0126 (6)	0.0136 (6)	0.0010 (5)	0.0029 (5)	0.0006 (5)
C6	0.0117 (7)	0.0189 (7)	0.0250 (7)	−0.0002 (5)	0.0008 (5)	−0.0032 (6)
C7	0.0128 (7)	0.0257 (8)	0.0316 (8)	0.0019 (6)	−0.0001 (6)	0.0016 (6)
C8	0.0139 (8)	0.0426 (10)	0.0409 (10)	0.0023 (7)	−0.0038 (7)	−0.0053 (8)
N4	0.0123 (5)	0.0071 (5)	0.0108 (5)	−0.0002 (4)	0.0024 (4)	0.0009 (4)
N5	0.0149 (6)	0.0081 (5)	0.0233 (6)	0.0003 (4)	0.0017 (5)	0.0026 (4)
N6	0.0129 (6)	0.0099 (5)	0.0323 (7)	0.0017 (4)	0.0025 (5)	0.0051 (5)
N7	0.0134 (6)	0.0110 (5)	0.0180 (5)	0.0013 (4)	−0.0016 (4)	0.0027 (4)
C9	0.0127 (6)	0.0113 (6)	0.0233 (7)	0.0019 (5)	0.0028 (5)	0.0060 (5)
C10	0.0194 (8)	0.0199 (7)	0.0460 (10)	0.0024 (6)	−0.0079 (7)	0.0092 (7)

Geometric parameters (Å, º)

Ni1—N1	2.0543 (12)	C5—C6	1.522 (2)
Ni1—N2	2.0661 (11)	C5—H5A	0.9900
Ni1—N4	2.2183 (11)	C5—H5B	0.9900
N1—C1	1.4752 (15)	C6—C7	1.519 (2)
N1—C2	1.4826 (15)	C6—H6A	0.9900
N1—H1	1.0000	C6—H6B	0.9900
N2—C4	1.4807 (17)	C7—C8	1.525 (2)
N2—C3	1.4860 (16)	C7—H7A	0.9900
N2—H2	1.0000	C7—H7B	0.9900
N3—C3	1.4474 (17)	C8—H8A	0.9800
N3—C2	1.4535 (16)	C8—H8B	0.9800
N3—C5	1.4657 (17)	C8—H8C	0.9800
C1—C4^i	1.5244 (17)	N4—N5	1.3182 (15)
C1—H1A	0.9900	N4—N7	1.3543 (16)
C1—H1B	0.9900	N5—N6	1.3469 (17)
C2—H2A	0.9900	N6—C9	1.3314 (19)
C2—H2B	0.9900	N7—C9	1.3347 (17)
C3—H3A	0.9900	C9—C10	1.494 (2)
C3—H3B	0.9900	C10—H10A	0.9800
C4—C1^i	1.5244 (17)	C10—H10B	0.9800
C4—H4A	0.9900	C10—H10C	0.9800
C4—H4B	0.9900
N1^i—Ni1—N1	180.0	H3A—C3—H3B	107.6
N1^i—Ni1—N2	86.04 (4)	N2—C4—C1^i	107.88 (10)
N1—Ni1—N2	93.96 (4)	N2—C4—H4A	110.1
N1^i—Ni1—N2^i	93.96 (4)	C1^i—C4—H4A	110.1
N1—Ni1—N2^i	86.04 (4)	N2—C4—H4B	110.1
N2—Ni1—N2^i	180.0	C1^i—C4—H4B	110.1
N1^i—Ni1—N4^i	85.15 (4)	H4A—C4—H4B	108.4
N1—Ni1—N4^i	94.86 (4)	N3—C5—C6	113.12 (11)
N2—Ni1—N4^i	92.11 (4)	N3—C5—H5A	109.0
N2^i—Ni1—N4^i	87.89 (4)	C6—C5—H5A	109.0
N1^i—Ni1—N4	94.86 (4)	N3—C5—H5B	109.0
N1—Ni1—N4	85.14 (4)	C6—C5—H5B	109.0
N2—Ni1—N4	87.89 (4)	H5A—C5—H5B	107.8
N2^i—Ni1—N4	92.11 (4)	C7—C6—C5	112.13 (12)
N4^i—Ni1—N4	180.0	C7—C6—H6A	109.2
C1—N1—C2	114.13 (10)	C5—C6—H6A	109.2
C1—N1—Ni1	105.32 (8)	C7—C6—H6B	109.2
C2—N1—Ni1	114.48 (8)	C5—C6—H6B	109.2
C1—N1—H1	107.5	H6A—C6—H6B	107.9
C2—N1—H1	107.5	C6—C7—C8	113.29 (14)
Ni1—N1—H1	107.5	C6—C7—H7A	108.9
C4—N2—C3	114.49 (10)	C8—C7—H7A	108.9
C4—N2—Ni1	105.31 (8)	C6—C7—H7B	108.9
C3—N2—Ni1	113.75 (7)	C8—C7—H7B	108.9
C4—N2—H2	107.7	H7A—C7—H7B	107.7
C3—N2—H2	107.7	C7—C8—H8A	109.5
Ni1—N2—H2	107.7	C7—C8—H8B	109.5
C3—N3—C2	115.80 (10)	H8A—C8—H8B	109.5
C3—N3—C5	113.60 (10)	C7—C8—H8C	109.5
C2—N3—C5	115.15 (10)	H8A—C8—H8C	109.5
N1—C1—C4^i	108.83 (10)	H8B—C8—H8C	109.5
N1—C1—H1A	109.9	N5—N4—N7	109.66 (11)
C4^i—C1—H1A	109.9	N5—N4—Ni1	130.78 (9)
N1—C1—H1B	109.9	N7—N4—Ni1	119.52 (8)
C4^i—C1—H1B	109.9	N4—N5—N6	108.96 (11)
H1A—C1—H1B	108.3	C9—N6—N5	105.08 (11)
N3—C2—N1	113.80 (10)	C9—N7—N4	104.21 (11)
N3—C2—H2A	108.8	N6—C9—N7	112.09 (13)
N1—C2—H2A	108.8	N6—C9—C10	124.23 (13)
N3—C2—H2B	108.8	N7—C9—C10	123.67 (13)
N1—C2—H2B	108.8	C9—C10—H10A	109.5
H2A—C2—H2B	107.7	C9—C10—H10B	109.5
N3—C3—N2	114.21 (10)	H10A—C10—H10B	109.5
N3—C3—H3A	108.7	C9—C10—H10C	109.5
N2—C3—H3A	108.7	H10A—C10—H10C	109.5
N3—C3—H3B	108.7	H10B—C10—H10C	109.5
N2—C3—H3B	108.7
C2—N1—C1—C4^i	168.66 (10)	C2—N3—C5—C6	−68.36 (14)
Ni1—N1—C1—C4^i	42.26 (11)	N3—C5—C6—C7	176.68 (12)
C3—N3—C2—N1	70.86 (14)	C5—C6—C7—C8	178.80 (14)
C5—N3—C2—N1	−65.05 (14)	N7—N4—N5—N6	0.63 (15)
C1—N1—C2—N3	−177.96 (10)	Ni1—N4—N5—N6	−177.06 (9)
Ni1—N1—C2—N3	−56.49 (12)	N4—N5—N6—C9	−0.27 (16)
C2—N3—C3—N2	−71.26 (14)	N5—N4—N7—C9	−0.72 (15)
C5—N3—C3—N2	65.32 (14)	Ni1—N4—N7—C9	177.28 (9)
C4—N2—C3—N3	177.73 (10)	N5—N6—C9—N7	−0.20 (17)
Ni1—N2—C3—N3	56.58 (12)	N5—N6—C9—C10	178.68 (15)
C3—N2—C4—C1^i	−167.67 (10)	N4—N7—C9—N6	0.56 (16)
Ni1—N2—C4—C1^i	−41.97 (10)	N4—N7—C9—C10	−178.32 (14)
C3—N3—C5—C6	154.78 (11)

Symmetry code: (i) −x+1/2, −y+3/2, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N7	1.00	2.07	2.8508 (16)	133
N2—H2···N6^ii	1.00	2.35	3.1403 (16)	135

Symmetry code: (ii) x, −y+1, z−1/2.