cis-Bis(tricyano­methanido-κN)[tris­(2-amino­ethyl)amine-κ⁴N]nickel(II)

The crystal structure of the title complex, [Ni(C₄N₃)₂(C₆H₁₈N₄)], is made up of neutral mononuclear [Ni(tren){C(CN)₃}₂] units [tren = tris­(2-amino­ethyl)amine] which are linked through van der Waals inter­actions and N—H...N hydrogen bonds. The Ni atom has a distorted octa­hedral coordination environment, bonded to the four tren N atoms [average Ni—N = 2.096 (17) Å] and the two cis-positioned C(CN)₃ N atoms [Ni—N = 2.045 (4) and 2.118 (4) Å].

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.041
• wR factor = 0.091
• Data-to-parameter ratio = 15.5

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       3.16 Ratio
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C5     -   C8      ..       5.06 su
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for        C21

Alert level G
ABSTY01_ALERT_1_G  Extra text has been found in the _exptl_absorpt_correction_type
            field, which should be only a single keyword. A literature
            citation should be included in the _exptl_absorpt_process_details
            field.
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           25.99
           From the CIF: _reflns_number_total               3504
           Count of symmetry unique reflns         2016
           Completeness (_total/calc)            173.81%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1488
           Fraction of Friedel pairs measured     0.738
           Are heavy atom types Z>Si present        yes
PLAT794_ALERT_5_G Check Predicted Bond Valency for Ni1         (2)       2.09

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

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

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S1. Comment

The title compound [Ni(tren){C(CN)₃}₂] (I) has been prepared by a chance during our attempts to prepare compounds suitable for magnetic studies containing a binuclear [Ni(tren)-µ-{C(CN)₃}₂(tren)Ni]²⁺ cation. The structure of (I) is made up of neutral [Ni(tren){C(CN)₃}₂] mononuclear units (Fig. 1). The nickel atom is six-coordinated: six nitrogen atoms from a tetradentate tren ligand and from two monodentate C(CN)₃ anionic ligands form a distorted octahedron around the metal atom. The Ni—N(tren) bond lengths [2.096 (17) Å on average] are very close to that of Ni—N(tren) found in other [Ni(tren)X₂] complexes with NiN₆ chromophore, where X is N(CN)₂ [2.11 (3) Å] (Březina et al., 1999), X is NO₂ [2.10 (3) Å] (Wen et al., 1998) and X is NCS [2.12 (3) Å] (Santarsiero & Schomaker, 1983) but are shorter than in the first report on this structure [2.18 (5) Å] (Rasmussen, 1959). The N4—Ni1—N1 angle which involves nitrogen atoms from two C(CN)₃ anions is nearly 90° but the angles around the nickel atom involving at least one nitrogen atom from the tren are much more deviated from the ideal values because of steric hindrances within the tren ligand.

The molecules of (I) are linked through van der Waals interactions and N—H···N hydrogen bonds involving all amine hydrogen atoms and uncoordinated nitrogen atoms of C(CN)₃; those with an N—H···N angle greater than 120° and an H···N distance less than 2.6 Å are given in Table. Through these hydrogen bonds, molecules are interconnected to form a three-dimensional structure as shown in Fig. 2.

Related literature

Thr first report on the title structure was by Rasmussen (1959). For related [Ni(tren)X₂] complexes, see: X = N(CN)₂ (Březina et al., 1999); X = NO₂ (Wen et al., 1998); X = NCS (Santarsiero & Schomaker, 1983).

S2. Experimental

The title compound [Ni(tren){C(CN)₃}₂] (I) has been prepared by a chance during our attempts to prepare compounds suitable for magnetic studies containing a binuclear [Ni(tren)-µ-{C(CN)₃}₂(tren)Ni]²⁺ cation. Crystals of (I) were prepared by mixing a 0.1 M aqueous solution of NiSO₄ (5 ml) with a 0.45 M aqueous solution of tren (1.2 ml). To the resulting violet solution, 64.6 mg of KC(CN)₃ (0.5 mmol) in 20 ml of water was added. Red-violet crystals of (I) appeared after 1 week. The crystals suitable for X-ray analysis were recrystallized from water and were filtered off and dried in air.

S3. Refinement

The structure was solved by direct method and subsequent Fourier syntheses. Anisotropic thermal parameters were refined for all non-H atoms. All H atoms positions were calculated using the appropriate riding model with isotropic temperature factors being 1.2 times larger than temperature factors of their parent carbon atoms.

Computing details

Data collection: COLLECT (Nonius, 1998) and DENZO (Otwinowski & Minor, 1997); cell refinement: COLLECT and DENZO; data reduction: COLLECT and DENZO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 2000); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The structure of (I) with the atom-labelling scheme. Displacement ellipsoids are drawn at the 40% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. Hydrogen bond system (dashed lines) in (I) viewed along the c axis. Methylene groups from the tren ligand are omitted because of clarity.

cis-Bis(tricyanomethanido-κN)[tris(2-aminoethyl)amine-κ⁴N]nickel(II))

Crystal data

[Ni(C4N3)2(C6H18N4)]	F(000) = 800
Mr = 385.07	Dx = 1.433 Mg m^−3
Orthorhombic, P21212	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2 2ab	Cell parameters from 13020 reflections
a = 14.4376 (11) Å	θ = 1–27.5°
b = 15.2861 (12) Å	µ = 1.11 mm^−1
c = 8.0888 (6) Å	T = 150 K
V = 1785.2 (2) Å^3	Block, red-violet
Z = 4	0.47 × 0.44 × 0.39 mm

Data collection

Nonius KappaCCD area-detector diffractometer	3504 independent reflections
Radiation source: fine-focus sealed tube	2761 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.077
Detector resolution: 9.091 pixels mm^-1	θmax = 26.0°, θmin = 1.9°
φ and ω scans to fill the Ewald sphere	h = −17→17
Absorption correction: gaussian integration (Coppens, 1970)	k = −18→18
Tmin = 0.589, Tmax = 0.672	l = −9→9
12191 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.041	H-atom parameters constrained
wR(F^2) = 0.091	w = 1/[σ^2(Fo^2) + (0.0365P)^2 + 0.6801P] where P = (Fo^2 + 2Fc^2)/3
S = 1.10	(Δ/σ)max < 0.001
3504 reflections	Δρmax = 0.34 e Å^−3
226 parameters	Δρmin = −0.66 e Å^−3
0 restraints	Absolute structure: Flack (1983), with how many Friedel pairs?
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.005 (19)

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 > 2σ(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
N6	0.2534 (3)	0.9161 (2)	0.9706 (4)	0.0416 (9)
Ni1	0.08457 (3)	0.76671 (3)	0.31260 (6)	0.02371 (13)
N30	0.21241 (19)	0.75188 (17)	0.1877 (4)	0.0340 (7)
H30A	0.2321	0.8043	0.1511	0.041*
H30B	0.2552	0.7305	0.2577	0.041*
N20	0.0409 (2)	0.8673 (2)	0.1579 (4)	0.0374 (9)
H20A	−0.0103	0.8924	0.2000	0.045*
H20B	0.0853	0.9083	0.1508	0.045*
N1	0.1272 (2)	0.6611 (2)	0.4640 (5)	0.0364 (9)
N4	0.1296 (2)	0.8525 (2)	0.4893 (4)	0.0325 (8)
N10	−0.0475 (2)	0.7439 (2)	0.4137 (4)	0.0412 (9)
H10A	−0.0420	0.7159	0.5111	0.049*
H10B	−0.0764	0.7951	0.4317	0.049*
C4	0.1484 (3)	0.9043 (2)	0.5869 (5)	0.0246 (8)
C5	0.1504 (2)	1.0555 (2)	0.6838 (6)	0.0278 (8)
N40	0.0362 (3)	0.6867 (2)	0.1225 (4)	0.0384 (9)
C6	0.2168 (3)	0.9393 (2)	0.8519 (5)	0.0292 (9)
N5	0.1342 (2)	1.1284 (2)	0.6661 (5)	0.0396 (8)
C1	0.1529 (3)	0.6058 (3)	0.5481 (6)	0.0288 (9)
C8	0.1717 (2)	0.9662 (2)	0.7062 (5)	0.0264 (8)
C3	0.2745 (3)	0.5457 (2)	0.7152 (5)	0.0312 (9)
C7	0.1853 (2)	0.5385 (2)	0.6483 (4)	0.0250 (9)
N2	0.0849 (3)	0.4021 (2)	0.6862 (6)	0.0684 (13)
C2	0.1307 (3)	0.4627 (3)	0.6701 (6)	0.0371 (10)
N3	0.3479 (3)	0.5551 (2)	0.7663 (5)	0.0498 (11)
C22	−0.0020 (3)	0.7412 (3)	−0.0137 (6)	0.0605 (14)
H22A	0.0209	0.7189	−0.1182	0.073*
H22B	−0.0689	0.7354	−0.0144	0.073*
C12	−0.0379 (3)	0.6326 (3)	0.1968 (7)	0.0486 (12)
H12A	−0.0106	0.5884	0.2676	0.058*
H12B	−0.0723	0.6031	0.1101	0.058*
C31	0.2008 (3)	0.6913 (3)	0.0461 (6)	0.0490 (12)
H31A	0.2556	0.6551	0.0354	0.059*
H31B	0.1938	0.7248	−0.0549	0.059*
C32	0.1169 (3)	0.6337 (3)	0.0701 (6)	0.0493 (13)
H32A	0.1026	0.6039	−0.0326	0.059*
H32B	0.1302	0.5898	0.1533	0.059*
C11	−0.1030 (3)	0.6896 (3)	0.2970 (7)	0.0506 (12)
H11A	−0.1384	0.7272	0.2239	0.061*
H11B	−0.1460	0.6532	0.3583	0.061*
C21	0.0215 (5)	0.8334 (4)	−0.0015 (7)	0.0778 (19)
H21A	0.0751	0.8439	−0.0709	0.093*
H21B	−0.0295	0.8668	−0.0477	0.093*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N6	0.054 (2)	0.044 (2)	0.027 (2)	0.0077 (18)	0.0011 (18)	0.0044 (17)
Ni1	0.0241 (2)	0.0228 (2)	0.0243 (2)	0.00161 (19)	−0.0009 (2)	−0.0035 (2)
N30	0.0366 (16)	0.0288 (19)	0.0366 (18)	0.0020 (12)	0.0076 (16)	0.0033 (18)
N20	0.0310 (17)	0.0383 (19)	0.043 (2)	0.0058 (15)	−0.0072 (16)	0.0025 (18)
N1	0.0317 (19)	0.033 (2)	0.044 (2)	−0.0041 (15)	0.0032 (17)	0.0078 (19)
N4	0.0374 (19)	0.0265 (19)	0.034 (2)	−0.0008 (15)	−0.0053 (16)	0.0011 (17)
N10	0.0303 (16)	0.040 (2)	0.054 (2)	−0.0032 (14)	0.0055 (16)	−0.0206 (18)
C4	0.026 (2)	0.025 (2)	0.023 (2)	0.0014 (15)	0.0001 (16)	0.0043 (18)
C5	0.0276 (18)	0.035 (2)	0.021 (2)	−0.0020 (15)	0.0008 (19)	−0.001 (2)
N40	0.045 (2)	0.038 (2)	0.032 (2)	0.0013 (16)	−0.0033 (16)	−0.0131 (16)
C6	0.033 (2)	0.027 (2)	0.027 (3)	0.0026 (16)	0.0073 (17)	−0.0027 (17)
N5	0.051 (2)	0.0295 (19)	0.038 (2)	0.0038 (16)	−0.0027 (18)	0.0054 (18)
C1	0.028 (2)	0.030 (2)	0.028 (2)	−0.0051 (17)	0.0049 (18)	−0.003 (2)
C8	0.037 (2)	0.0220 (19)	0.020 (2)	0.0016 (14)	−0.0013 (18)	0.0022 (18)
C3	0.044 (3)	0.028 (2)	0.022 (2)	−0.0044 (17)	0.007 (2)	0.0047 (18)
C7	0.033 (2)	0.0234 (19)	0.019 (2)	−0.0063 (15)	0.0000 (16)	0.0016 (16)
N2	0.086 (3)	0.055 (2)	0.064 (3)	−0.038 (2)	−0.035 (3)	0.031 (3)
C2	0.051 (2)	0.037 (2)	0.023 (2)	−0.0095 (19)	−0.016 (2)	0.011 (2)
N3	0.042 (2)	0.053 (2)	0.054 (3)	−0.0079 (18)	−0.0077 (18)	0.0130 (19)
C22	0.071 (3)	0.068 (4)	0.042 (3)	0.010 (3)	−0.024 (2)	−0.013 (3)
C12	0.044 (2)	0.039 (2)	0.062 (3)	−0.0110 (19)	0.000 (3)	−0.023 (3)
C31	0.058 (3)	0.047 (3)	0.042 (3)	0.009 (2)	0.022 (2)	−0.004 (2)
C32	0.070 (3)	0.041 (3)	0.037 (3)	0.004 (2)	0.011 (2)	−0.022 (2)
C11	0.028 (2)	0.052 (3)	0.072 (4)	−0.0100 (17)	0.005 (2)	−0.019 (3)
C21	0.109 (5)	0.068 (4)	0.057 (4)	−0.019 (3)	−0.052 (3)	0.018 (3)

Geometric parameters (Å, º)

Ni1—N4	2.045 (4)	N6—C6	1.152 (5)
Ni1—N20	2.080 (3)	C6—C8	1.408 (6)
Ni1—N40	2.085 (3)	C1—C7	1.391 (6)
Ni1—N10	2.104 (3)	C3—N3	1.146 (5)
Ni1—N30	2.116 (3)	C3—C7	1.401 (6)
Ni1—N1	2.118 (4)	C7—C2	1.413 (5)
N30—C31	1.482 (5)	N2—C2	1.145 (5)
N30—H30A	0.9000	C22—C21	1.453 (7)
N30—H30B	0.9000	C22—H22A	0.9700
N20—C21	1.418 (6)	C22—H22B	0.9700
N20—H20A	0.9000	C12—C11	1.517 (6)
N20—H20B	0.9000	C12—H12A	0.9700
N1—C1	1.146 (5)	C12—H12B	0.9700
N4—C4	1.151 (5)	C31—C32	1.509 (6)
N10—C11	1.490 (5)	C31—H31A	0.9700
N10—H10A	0.9000	C31—H31B	0.9700
N10—H10B	0.9000	C32—H32A	0.9700
C4—C8	1.393 (6)	C32—H32B	0.9700
C5—N5	1.148 (4)	C11—H11A	0.9700
C5—C8	1.411 (5)	C11—H11B	0.9700
N40—C12	1.479 (6)	C21—H21A	0.9700
N40—C32	1.482 (5)	C21—H21B	0.9700
N40—C22	1.488 (6)
N4—Ni1—N20	92.46 (14)	C4—C8—C6	119.5 (3)
N4—Ni1—N40	176.02 (14)	C4—C8—C5	121.1 (4)
N20—Ni1—N40	83.56 (14)	C6—C8—C5	119.4 (4)
N4—Ni1—N10	97.05 (13)	N3—C3—C7	176.9 (4)
N20—Ni1—N10	94.67 (14)	C1—C7—C3	118.4 (3)
N40—Ni1—N10	83.42 (14)	C1—C7—C2	119.5 (3)
N4—Ni1—N30	97.20 (13)	C3—C7—C2	122.0 (3)
N20—Ni1—N30	93.24 (13)	N2—C2—C7	178.6 (5)
N40—Ni1—N30	82.96 (13)	C21—C22—N40	114.0 (4)
N10—Ni1—N30	163.37 (12)	C21—C22—H22A	108.8
N4—Ni1—N1	89.55 (13)	N40—C22—H22A	108.8
N20—Ni1—N1	177.99 (14)	C21—C22—H22B	108.8
N40—Ni1—N1	94.43 (14)	N40—C22—H22B	108.8
N10—Ni1—N1	84.97 (14)	H22A—C22—H22B	107.7
N30—Ni1—N1	86.61 (12)	N40—C12—C11	110.1 (3)
C31—N30—Ni1	109.7 (2)	N40—C12—H12A	109.6
C31—N30—H30A	109.7	C11—C12—H12A	109.6
Ni1—N30—H30A	109.7	N40—C12—H12B	109.6
C31—N30—H30B	109.7	C11—C12—H12B	109.6
Ni1—N30—H30B	109.7	H12A—C12—H12B	108.2
H30A—N30—H30B	108.2	N30—C31—C32	110.9 (4)
C21—N20—Ni1	109.7 (3)	N30—C31—H31A	109.5
C21—N20—H20A	109.7	C32—C31—H31A	109.5
Ni1—N20—H20A	109.7	N30—C31—H31B	109.5
C21—N20—H20B	109.7	C32—C31—H31B	109.5
Ni1—N20—H20B	109.7	H31A—C31—H31B	108.1
H20A—N20—H20B	108.2	N40—C32—C31	110.4 (4)
C1—N1—Ni1	177.5 (3)	N40—C32—H32A	109.6
C4—N4—Ni1	174.6 (3)	C31—C32—H32A	109.6
C11—N10—Ni1	109.5 (2)	N40—C32—H32B	109.6
C11—N10—H10A	109.8	C31—C32—H32B	109.6
Ni1—N10—H10A	109.8	H32A—C32—H32B	108.1
C11—N10—H10B	109.8	N10—C11—C12	109.0 (3)
Ni1—N10—H10B	109.8	N10—C11—H11A	109.9
H10A—N10—H10B	108.2	C12—C11—H11A	109.9
N4—C4—C8	179.4 (4)	N10—C11—H11B	109.9
N5—C5—C8	179.1 (4)	C12—C11—H11B	109.9
C12—N40—C32	112.3 (3)	H11A—C11—H11B	108.3
C12—N40—C22	110.3 (4)	N20—C21—C22	117.5 (4)
C32—N40—C22	112.7 (4)	N20—C21—H21A	107.9
C12—N40—Ni1	105.7 (3)	C22—C21—H21A	107.9
C32—N40—Ni1	105.5 (3)	N20—C21—H21B	107.9
C22—N40—Ni1	110.0 (3)	C22—C21—H21B	107.9
N6—C6—C8	179.0 (4)	H21A—C21—H21B	107.2
N1—C1—C7	179.1 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N30—H30A···N6^i	0.90	2.27	3.119 (5)	158
N30—H30B···N5^ii	0.90	2.32	3.141 (4)	152
N20—H20A···N3^iii	0.90	2.22	3.090 (5)	164
N20—H20B···N3^iv	0.90	2.53	3.347 (5)	151
N10—H10A···N2^v	0.90	2.38	3.183 (6)	149
N10—H10B···N5^vi	0.90	2.38	3.090 (5)	136

Symmetry codes: (i) x, y, z−1; (ii) −x+1/2, y−1/2, −z+1; (iii) x−1/2, −y+3/2, −z+1; (iv) −x+1/2, y+1/2, −z+1; (v) −x, −y+1, z; (vi) −x, −y+2, z.