[N-(2-Hydroxy­ethyl)ethyl­enediamine-κ³N,N′,O]-cis-bis(isothio­cyanato-κN)copper(II)

In the novel transition metal isothio­cyanate complex of N-(2-hydroxy­ethyl)ethyl­enediamine (hydet-en) with copper, [Cu(NCS)₂(C₄H₁₂N₂O)], the Cu atom lies in a distorted square-pyramidal environment, coordinated by four N atoms in the basal plane and an apical O atom. The hydet-en ligand is N,N,O-tridentate, in contrast to the disposition in previously studied complexes, while the isothio­cyanate ions act as N-atom donor ligands. The monomeric units are linked to one another by hydrogen bonds.

S1. Comment

Studies of the syntheses, structures and properties of metal complexes containing ambidentate ligands are of interest for a number of reasons, some of which involve controlling the reactivities of the coordination sites in the metal complexes. Many transition metal complexes of this type have been synthesized, and their structures and physical properties, as well as the linkage isomerization reactions of the ambidentate units, have been investigated (Kabesova et al., 1995; Buckingham, 1994; Burmeister, 1990). The coordination mode of an ambidentate ligand depends strongly on the nature of the central metal and the adjacent ligands. In this context, we have undertaken a study of the effect of the ligand N-(2-hydroxyethyl)ethylenediamine (hydet-en) on the coordination behaviour of thiocyanate ions in copper complexes. Hydet-en, with three donor sites, has been the subject of few studies (Yılmaz et al., 2002; Karadaǧ et al., 2004), and its coordination behaviour is, therefore, not well characterized. The present paper reports the synthesis and crystal structure determination of the compound [Cu(hydet-en)(SCN)₂], (I).

An ORTEPIII (Burnett & Johnson, 1996) view of the molecular structure of (I) is shown in Fig. 1. The structure consists of monomeric units, which are connected by hydrogen bonds.

Each Cu^II ion has square-pyramidal geometry and is coordinated by one hydet-en ligand and two isothiocyanate ions, which are mutually cis. The hydet-en ligand chelates through its two amine N atoms and the O atom of the ethanol group, an arrangement that is different from those observed in the copper and cadmium saccharin complexes with the hydet-en ligand (Yılmaz et al., 2002), the cyano-bridged Zn^II/Ni^II complex (Karadaǧ et al., unpublished results) and the nickel isothiocyanate complex (Karadaǧ et al., 2004).

A topological ambiguity exists in the structure, in that it would have been possible to assign atoms N4 and O1 as shown in Fig. 1 or with their identities reversed. The possibility of disorder also had to be considered. However, since N4 donates two hydrogen bonds, while O1 donates one, the correct assignment was clear.

The square-pyramidal coordination shell consists of two chelated five-membered rings, A (Cu1/O1/C3/C4/N3) and B (Cu1/N3/C5/C6/N4), with a dihedral angle between the mean planes through A and B of 70.20 (11)°. The isothiocyanate ions act as N-atom donor ligands, as reported in related studies (Xu et al., 2003; Yılmaz et al., 2000). The coordinated amine N atoms of the hydet-en ligands and the N atoms of two isothiocyanate ions form the basal plane (N1–N4), while the O atom of the ethanol group of the hydet-en ligand is located in the axial position. The Cu—N distances are comparable to those in a previously reported Cu–hydet-en complex (Yılmaz et al., 2002). The bite angles of rings A and B are 77.70 (14) and 83.84 (15)°, respectively. The other cis angles around the Cu atom deviate slightly from 90°, completing the basal plane along with the bite angle of ring A. The isothiocyanate groups are almost linear; the S—C and C—N distances (Table 1) agree with the values in the literature (Yılmaz et al., 2000). Other than the chelate bite angles, the bond angles around the Cu^II center deviate only slightly from the ideal angles for square-pyramidal geometry.

The molecule, which constitutes the asymmetric unit, is linked by hydrogen bonds to surrounding molecules (N3—H6···S1ⁱ, N4—H11···S1ⁱⁱ, N4—H12···S2ⁱⁱⁱ and O1—H1···S1^iv; symmetry operations as in Table 2). The crystal packing is shown in Fig. 2.

S2. Experimental

CuCl₂·H₂ O (0.17 gr, 1 mmol) in water (10 ml) was mixed with KSCN (0.197 gr, 2 mmol) for 5 min. hydet-en (0.105 gr, 1 mmol) in ethanol (10 ml) was added to the mixture, which was stirred well at room temparature. On slow evaporation of the resulting violet solution, single crystals suitable for X-ray diffraction analysis were obtained within a week and were separed by filtration, washed and air dried.

S3. Refinement

All of the H atoms, except H1, were placed in calculated positions and refined as riding atoms [C—H = 0.97 Å, N—H = 0.90–0.91 Å and U_iso(H) = 1.2U_eq(C,N)]. Treatment of atom H1? The absolute structure was established by refining the Flack parameter (Flack, 1983).

Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. The molecular structure of (I). Displacement ellipsoids are shown at the ??% probability level.
	Fig. 2. A packing diagram of (I). Hydrogen bonds are shown as dashed lines.

[N-(2-hydroxyethyl)ethylendiamine-κ³N,N',O] cis-bis(isothiocyanato-κN)copper(II)

Crystal data

[Cu(C4H12N2O)(CNS)2]	F(000) = 580
Mr = 283.86	Dx = 1.607 Mg m^−3
Monoclinic, Cc	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: C -2yc	Cell parameters from 10025 reflections
a = 7.312 (5) Å	θ = 2.8–26.3°
b = 14.774 (5) Å	µ = 2.19 mm^−1
c = 10.902 (5) Å	T = 293 K
β = 95.076 (5)°	Prism, violet
V = 1173.1 (10) Å^3	0.40 × 0.35 × 0.28 mm
Z = 4

Data collection

Stoe IPDS-II diffractometer	2231 independent reflections
Radiation source: fine-focus sealed tube	1795 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.067
Detector resolution: 6.67 pixels mm^-1	θmax = 26.0°, θmin = 2.8°
ω scans	h = −9→9
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)	k = −18→18
Tmin = 0.433, Tmax = 0.541	l = −13→12
7769 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)] = 0.031	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.059	w = 1/[σ^2(Fo^2) + (0.0234P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.90	(Δ/σ)max = 0.001
2231 reflections	Δρmax = 0.30 e Å^−3
131 parameters	Δρmin = −0.27 e Å^−3
2 restraints	Absolute structure: Flack (1983), 1074 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.014 (16)

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
Cu1	0.04410 (5)	0.15925 (3)	0.71828 (4)	0.03682 (13)
S1	−0.36734 (15)	−0.05230 (9)	0.86694 (11)	0.0542 (3)
S2	0.13872 (16)	0.24779 (11)	1.13431 (11)	0.0647 (4)
C1	−0.2344 (6)	0.0189 (3)	0.8038 (4)	0.0344 (10)
O1	0.2768 (5)	0.0510 (3)	0.7305 (3)	0.0601 (10)
C2	0.1066 (6)	0.2209 (3)	0.9910 (4)	0.0420 (10)
N3	0.0369 (5)	0.1146 (3)	0.5434 (3)	0.0444 (9)
H6	−0.0831	0.1123	0.5133	0.053*
N4	0.1621 (5)	0.2685 (2)	0.6510 (3)	0.0483 (9)
H11	0.1231	0.3188	0.6872	0.058*
H12	0.2849	0.2651	0.6663	0.058*
C5	0.1292 (7)	0.1802 (4)	0.4677 (4)	0.0644 (15)
H7	0.0742	0.1780	0.3834	0.077*
H8	0.2579	0.1645	0.4675	0.077*
C4	0.1111 (7)	0.0216 (4)	0.5392 (4)	0.0576 (13)
H4	0.0258	−0.0202	0.5722	0.069*
H5	0.1234	0.0050	0.4542	0.069*
N1	−0.1373 (5)	0.0695 (3)	0.7616 (3)	0.0489 (10)
C6	0.1122 (6)	0.2726 (4)	0.5170 (4)	0.0655 (16)
H9	0.1937	0.3136	0.4786	0.079*
H10	−0.0127	0.2943	0.5003	0.079*
N2	0.0843 (6)	0.2014 (3)	0.8882 (4)	0.0590 (11)
C3	0.2913 (8)	0.0142 (5)	0.6104 (5)	0.0660 (17)
H3	0.3284	−0.0488	0.6169	0.079*
H2	0.3830	0.0472	0.5694	0.079*
H1	0.374 (6)	0.042 (3)	0.773 (4)	0.044 (14)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0425 (2)	0.0394 (2)	0.0298 (2)	−0.0054 (3)	0.01068 (16)	0.0026 (3)
S1	0.0428 (6)	0.0581 (7)	0.0624 (8)	−0.0081 (6)	0.0074 (5)	0.0240 (6)
S2	0.0588 (8)	0.0985 (11)	0.0382 (6)	−0.0161 (7)	0.0128 (5)	−0.0182 (7)
C1	0.032 (2)	0.037 (3)	0.033 (2)	0.002 (2)	−0.0037 (19)	0.003 (2)
O1	0.046 (2)	0.090 (3)	0.0424 (19)	0.025 (2)	−0.0044 (16)	−0.0074 (19)
C2	0.044 (2)	0.047 (3)	0.037 (2)	−0.007 (2)	0.0115 (19)	−0.0005 (19)
N3	0.0356 (19)	0.066 (3)	0.0313 (18)	−0.0040 (17)	−0.0006 (14)	−0.0010 (18)
N4	0.047 (2)	0.044 (2)	0.056 (2)	−0.0040 (17)	0.0171 (18)	0.0023 (18)
C5	0.072 (3)	0.093 (4)	0.029 (2)	−0.019 (3)	0.007 (2)	0.011 (2)
C4	0.068 (3)	0.065 (3)	0.040 (3)	0.000 (3)	0.005 (2)	−0.018 (2)
N1	0.043 (2)	0.055 (3)	0.049 (2)	−0.0060 (19)	0.0034 (18)	0.015 (2)
C6	0.048 (3)	0.084 (4)	0.065 (3)	0.002 (3)	0.013 (3)	0.045 (3)
N2	0.078 (3)	0.057 (3)	0.044 (2)	−0.013 (2)	0.016 (2)	−0.004 (2)
C3	0.061 (4)	0.084 (5)	0.054 (3)	0.020 (3)	0.013 (3)	−0.014 (3)

Geometric parameters (Å, º)

Cu1—N2	1.952 (4)	N4—C6	1.475 (5)
Cu1—N1	1.963 (4)	N4—H11	0.9000
Cu1—N4	2.000 (3)	N4—H12	0.9000
Cu1—N3	2.013 (3)	C5—C6	1.476 (8)
Cu1—O1	2.331 (4)	C5—H7	0.9700
S1—C1	1.626 (5)	C5—H8	0.9700
S2—C2	1.608 (4)	C4—C3	1.473 (7)
C1—N1	1.154 (6)	C4—H4	0.9700
O1—C3	1.429 (6)	C4—H5	0.9700
O1—H1	0.82 (4)	C6—H9	0.9700
C2—N2	1.155 (5)	C6—H10	0.9700
N3—C5	1.475 (6)	C3—H3	0.9700
N3—C4	1.479 (6)	C3—H2	0.9700
N3—H6	0.9100
N2—Cu1—N1	92.02 (17)	N3—C5—C6	110.3 (4)
N2—Cu1—N4	93.29 (16)	N3—C5—H7	109.6
N1—Cu1—N4	162.99 (15)	C6—C5—H7	109.6
N2—Cu1—N3	172.84 (17)	N3—C5—H8	109.6
N1—Cu1—N3	92.59 (15)	C6—C5—H8	109.6
N4—Cu1—N3	83.84 (15)	H7—C5—H8	108.1
N2—Cu1—O1	96.70 (16)	C3—C4—N3	111.5 (5)
N1—Cu1—O1	91.62 (15)	C3—C4—H4	109.3
N4—Cu1—O1	103.77 (15)	N3—C4—H4	109.3
N3—Cu1—O1	77.70 (14)	C3—C4—H5	109.3
N1—C1—S1	178.3 (4)	N3—C4—H5	109.3
C3—O1—Cu1	108.8 (3)	H4—C4—H5	108.0
C3—O1—H1	109 (3)	C1—N1—Cu1	170.5 (4)
Cu1—O1—H1	137 (3)	N4—C6—C5	107.6 (4)
N2—C2—S2	179.6 (5)	N4—C6—H9	110.2
C5—N3—C4	113.9 (4)	C5—C6—H9	110.2
C5—N3—Cu1	109.9 (3)	N4—C6—H10	110.2
C4—N3—Cu1	110.8 (3)	C5—C6—H10	110.2
C5—N3—H6	107.3	H9—C6—H10	108.5
C4—N3—H6	107.3	C2—N2—Cu1	175.8 (4)
Cu1—N3—H6	107.3	O1—C3—C4	108.6 (4)
C6—N4—Cu1	108.6 (3)	O1—C3—H3	110.0
C6—N4—H11	110.0	C4—C3—H3	110.0
Cu1—N4—H11	110.0	O1—C3—H2	110.0
C6—N4—H12	110.0	C4—C3—H2	110.0
Cu1—N4—H12	110.0	H3—C3—H2	108.3
H11—N4—H12	108.3

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N3—H6···S1^i	0.91	2.66	3.505 (4)	155
N4—H11···S1^ii	0.90	2.73	3.562 (4)	155
N4—H12···S2^iii	0.90	2.65	3.514 (4)	162
O1—H1···S1^iv	0.82 (4)	2.49 (5)	3.260 (4)	155 (4)

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