trans-Bis­(diethano­lamine)­bis­(iso­thio­cyanato)­nickel(II)

In the neutral title complex, trans-bis(2,2'-imino­di­ethanol-N,O)­bis­(iso­thio­cyanato)­nickel(II), [Ni(NCS)₂(C₄H₁₁NO₂)₂], the iso­thio­cyanate ions and the di­ethanol­amine mol­ecules act as mono­dentate and bi­dentate ligands, respectively. The Ni^II ion exhibits a distorted octahedral configuration with crystallographically imposed inversion symmetry and N_NCS-Ni-N_amine and N_NCS-Ni-O_amine bond angles of 88.78 (10) and 89.44 (10)°, respectively. The Ni-N bond distances are in the range 2.069 (3)-2.096 (2) Å. The mol­ecules are linked by hydrogen bonds to form a three-dimensional infinite lattice.

S1. Comment

As part of our study on the synthesis and spectral and thermal analysis of transition metal complexes of ethanolamines (İçbudak et al., 1995; Karada\-g & Yilmaz, 2000), we describe here the structure of the title complex, (I), resulting from the reaction of diethanolamine with KSCN and NiSO₄^.6 H₂O. \sch

The Ni^II ion is octahedrally coordinated by the two mutually trans diethanolamine molecules and the two mutually trans isocyanate ions. Each diethanolamine acts as bidentate donor, through one N atom and one O atom (O1); the other ethanolic group containing O2 does not participate in coordination. The coordinating N and O atoms of diethanolamine are positioned in the equatorial plane of the octahedron, while the monodentate isothiocyanate ions occupy the axial positions (Fig. 1). The Ni—N_amine bonds [2.096 (3) Å] are somewhat longer than the Ni—N _{isothiocyanate} bonds [2.069 (3) Å] and these Ni—N bond distances are comparable with the those found in the monoethanolamine analogous to the Ni^II complex [2.085 (5) and 2.065 (5) Å, respectively (Hursthouse et al., 1990)]. The Ni—O distances in the title complex are 2.076 (2) Å and also comparable with those in related di- and triethanolamine complexes of Ni^II reported by Hursthouse et al.(1990) and İçbudak et al. (1995) of 2.094 (4) and 2.068 (1) Å, respectively.

The N_{isothiocyanate}—Ni—N_amine, N_{isothiocyanate}—Ni—O and N _amine—Ni—O bond angles of 91.22 (10), 89.44 (10) and 83.16 (9)°, respectively, indicate significant distortion from ideally octahedral of the coordination geometry around Ni^II.

The NCS groups are almost linear, but significant bending is observed in the Ni—N—C(—S) linkage [Ni—N1—C1, 173.4 (3)]. The NCS, NH and free OH groups are involved in intermolecular hydrogen bonding. The H atoms of the NH and uncoordinated OH groups form hydrogen bonds with the S atom of adjacent molecules and the H atoms of coordinated OH groups also participate in hydrogen bonding with the H atom of the free OH groups of other molecules. The individual molecules are thus linked by hydrogen bonds to form a three-dimensional infinite network, part of which is shown in Fig. 2. Similar hydrogen bonding has been reported for other ethanolamine compounds (Yilmaz et al., 1996; Yilmaz et al., 1997).

S2. Experimental

Solid KSCN (1.94 g, 20 mmol) was added slowly and with continuous stirring to a solution of NiSO₄·6H₂O (2.63 g, 10 mmol) in distilled water (15 ml). Diethanolamine (2.10 g, 20 mmol) was dissolved in distilled water (20 ml) and the two solutions mixed and stirred for 2 h. A pale green polycrystalline precipitate was filtered off and blue crystals suitable for X-ray diffraction analysis were obtained by slow evaporation from the resulting solution at room temperature.

S3. Refinement

Hydrogen atoms bonded to O and N were identified from difference syntheses and refined freely. Other H were included using a riding model (Sheldrick, 1997). The crystal is a non-merohedral twin. The twin-matrix was determined as (100/010/3/401) and the refined value of −0.7592 rather than −0.75 was derived from XPREP using the equation c(new) = (2c cos β)/a − c(old) to obtain the exact cell parameters. Reflections with h = 4 and 8 show partial overlapping and are therefore omitted. Reflections with h = 0 are split into two components with a refined BASF value of 0.216 (4). The resulting data set was read using HKLF 5 (Sheldrick, 1997).

Computing details

Data collection: XSCANS (Fait, 1991); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Siemens, 1994b); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The structure of the title complex with the atom-numbering scheme. Displacement ellipsoids are shown at the 50% probability level. H atoms are omitted for clarity. Symmetry code: (i) −x, 1 − y, 1 − z.
	Fig. 2. A view along the b direction showing hydrogen bonding. H atoms not involved in hydrogen bonding are omitted.

Bis(2,2\'-iminodiethanol)bis(isothiocyanato)nickel(II)

Crystal data

[Ni(SCN)2(C4H11NO2)2]	Dx = 1.550 Mg m^−3
Mr = 385.15	Melting point: 476 K
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 6.8157 (8) Å	Cell parameters from 62 reflections
b = 8.3508 (10) Å	θ = 4–12.5°
c = 14.725 (2) Å	µ = 1.45 mm^−1
β = 100.119 (10)°	T = 173 K
V = 825.08 (18) Å^3	Square prism, blue
Z = 2	0.30 × 0.16 × 0.14 mm
F(000) = 404

Data collection

Siemens P4 diffractometer	1072 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.000
Graphite monochromator	θmax = 27.5°, θmin = 3.1°
ω–scans	h = −7→7
Absorption correction: psi-scan (XEMP; Siemens 1994a)	k = −10→10
Tmin = 0.773, Tmax = 0.798	l = −18→18
1568 measured reflections	3 standard reflections every 247 reflections
1568 independent reflections	intensity decay: none

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.071	H atoms treated by a mixture of independent and constrained refinement
S = 0.93	w = 1/[σ^2(Fo^2) + (0.0316P)^2] where P = (Fo^2 + 2Fc^2)/3
1568 reflections	(Δ/σ)max < 0.001
110 parameters	Δρmax = 0.35 e Å^−3
0 restraints	Δρmin = −0.36 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.

The crystal is a non-merohedral twin. The twin-matrix was determined as 1 0 0 0 − 1 0 − 0.75 0 − 1 and the refined value of −0.7592 was derived from XPREP using the equation c(new) = (2c cos β)/a − c(old) to obtain the exact cell parameters. Reflections with h = 4 and 8 show partial overlapping and are therefore omitted. Reflections with h = 0 are split into two components with a refined BASF value of 0.21564 (416). The complete refinement was performed using HKLF 5.

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

	x	y	z	Uiso*/Ueq
Ni1	0.0000	0.5000	0.5000	0.01420 (14)
S1	0.22997 (14)	0.15137 (11)	0.27554 (6)	0.0283 (2)
O1	0.2858 (3)	0.5809 (3)	0.55181 (15)	0.0193 (5)
H1	0.294 (6)	0.606 (4)	0.599 (3)	0.033 (12)*
N2	−0.0050 (4)	0.6987 (3)	0.41268 (16)	0.0170 (6)
H2	0.036 (5)	0.661 (3)	0.364 (2)	0.018 (8)*
N1	0.1135 (4)	0.3647 (3)	0.40347 (16)	0.0201 (6)
C1	0.1627 (5)	0.2782 (4)	0.35009 (19)	0.0170 (7)
C21	−0.2004 (5)	0.7761 (4)	0.3828 (2)	0.0208 (7)
H21A	−0.2393	0.8307	0.4366	0.025*
H21B	−0.3007	0.6917	0.3626	0.025*
C12	0.1540 (5)	0.8078 (4)	0.4576 (2)	0.0225 (7)
H12A	0.1085	0.8666	0.5085	0.027*
H12B	0.1862	0.8870	0.4124	0.027*
C22	−0.2075 (5)	0.8970 (4)	0.3053 (2)	0.0246 (8)
H22A	−0.3434	0.9423	0.2894	0.030*
H22B	−0.1138	0.9858	0.3257	0.030*
C11	0.3379 (5)	0.7089 (4)	0.4952 (2)	0.0239 (7)
H11A	0.3951	0.6640	0.4434	0.029*
H11B	0.4398	0.7781	0.5322	0.029*
O2	−0.1544 (4)	0.8212 (3)	0.22578 (15)	0.0344 (7)
H3	−0.033 (6)	0.805 (5)	0.233 (3)	0.044 (12)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0146 (3)	0.0177 (3)	0.0105 (2)	−0.0007 (3)	0.00266 (19)	−0.0007 (3)
S1	0.0324 (5)	0.0274 (5)	0.0295 (4)	−0.0063 (4)	0.0179 (4)	−0.0111 (4)
O1	0.0195 (12)	0.0240 (13)	0.0140 (10)	−0.0031 (11)	0.0019 (10)	0.0011 (9)
N2	0.0171 (14)	0.0220 (15)	0.0126 (11)	0.0002 (13)	0.0046 (11)	0.0013 (10)
N1	0.0219 (15)	0.0232 (15)	0.0163 (12)	−0.0016 (13)	0.0065 (11)	0.0013 (11)
C1	0.0151 (15)	0.0206 (17)	0.0155 (13)	−0.0012 (14)	0.0027 (12)	0.0022 (13)
C21	0.0199 (16)	0.0221 (18)	0.0201 (14)	0.0027 (15)	0.0026 (13)	0.0015 (13)
C12	0.0240 (18)	0.0218 (18)	0.0205 (14)	−0.0059 (16)	0.0005 (14)	0.0050 (13)
C22	0.0208 (18)	0.0294 (19)	0.0231 (15)	0.0010 (16)	0.0022 (14)	0.0070 (14)
C11	0.0177 (16)	0.0298 (19)	0.0231 (15)	−0.0081 (16)	0.0008 (13)	0.0058 (14)
O2	0.0238 (14)	0.0579 (19)	0.0205 (11)	0.0124 (14)	0.0015 (11)	0.0128 (11)

Geometric parameters (Å, º)

Ni1—N1	2.069 (3)	O1—C11	1.438 (4)
Ni1—N1^i	2.069 (3)	N2—C21	1.476 (4)
Ni1—N2	2.096 (2)	N2—C12	1.480 (4)
Ni1—O1^i	2.076 (2)	N1—C1	1.159 (4)
Ni1—O1	2.076 (2)	C21—C22	1.518 (4)
Ni1—N2^i	2.096 (2)	C12—C11	1.522 (4)
S1—C1	1.647 (3)	C22—O2	1.432 (4)
N1—Ni1—N1^i	180.00 (9)	O1—Ni1—N2^i	96.84 (9)
N1—Ni1—N2	88.78 (10)	N2—Ni1—N2^i	180.000 (1)
N1—Ni1—O1^i	90.56 (10)	Ni1—O1—C11	109.89 (18)
N1^i—Ni1—O1^i	89.44 (10)	C21—N2—C12	114.5 (3)
N1—Ni1—O1	89.44 (10)	Ni1—N2—C21	116.5 (2)
N1^i—Ni1—O1	90.56 (10)	Ni1—N2—C12	106.34 (18)
O1^i—Ni1—O1	180.0	Ni1—N1—C1	173.4 (3)
N1^i—Ni1—N2	91.22 (10)	N1—C1—S1	178.5 (3)
O1^i—Ni1—N2	96.84 (9)	N2—C21—C22	115.0 (3)
N2—Ni1—O1	83.16 (9)	N2—C12—C11	108.7 (3)
N1—Ni1—N2^i	91.22 (10)	O2—C22—C21	110.0 (3)
N1^i—Ni1—N2^i	88.78 (10)	O1—C11—C12	110.0 (3)
O1^i—Ni1—N2^i	83.16 (9)
N1—Ni1—O1—C11	80.9 (2)	N2^i—Ni1—N2—C12	6 (100)
N1^i—Ni1—O1—C11	−99.1 (2)	N1^i—Ni1—N1—C1	117 (100)
O1^i—Ni1—O1—C11	104 (100)	O1^i—Ni1—N1—C1	−33 (2)
N2—Ni1—O1—C11	−8.0 (2)	O1—Ni1—N1—C1	147 (2)
N2^i—Ni1—O1—C11	172.0 (2)	N2—Ni1—N1—C1	−130 (2)
N1—Ni1—N2—C21	121.7 (2)	N2^i—Ni1—N1—C1	50 (2)
N1^i—Ni1—N2—C21	−58.3 (2)	Ni1—N1—C1—S1	−26 (13)
O1^i—Ni1—N2—C21	31.3 (2)	C12—N2—C21—C22	66.8 (3)
O1—Ni1—N2—C21	−148.7 (2)	Ni1—N2—C21—C22	−168.2 (2)
N2^i—Ni1—N2—C21	−123 (100)	C21—N2—C12—C11	173.0 (2)
N1—Ni1—N2—C12	−109.3 (2)	Ni1—N2—C12—C11	42.9 (3)
N1^i—Ni1—N2—C12	70.7 (2)	N2—C21—C22—O2	59.0 (4)
O1^i—Ni1—N2—C12	160.3 (2)	Ni1—O1—C11—C12	33.9 (3)
O1—Ni1—N2—C12	−19.7 (2)	N2—C12—C11—O1	−52.3 (3)

Symmetry code: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O2^ii	0.72 (4)	1.93 (4)	2.651 (3)	174 (5)
N2—H2···S1^iii	0.88 (3)	2.81 (3)	3.630 (3)	156 (3)
O2—H3···S1^iii	0.83 (4)	2.45 (4)	3.225 (3)	156 (4)

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