Bis­(ethyl­enedi­amine)copper(II) bis(O,O'-diethyl di­thio­phosphate)

In the structure of the title compound, [Cu^II­(en)₂][(EtO)₂P(S)S]₂ (en is ethyl­ene­di­amine) or [Cu(C₂H₈N₂)₂](C₄H₁₀O₂PS₂)₂, the Cu atom lies on a center of inversion and is coordinated in a slightly distorted square coordination geometry by four N atoms from two ethyl­enedi­amine mol­ecules. The diethyl di­thio­phosphate moieties, (EtO)₂P(S)S^-, act as counter-anions.

S1. Comment

Compounds of bivalent copper exhibit different coordination arrangements, some being apparently four-coordinate, whereas others are generally five- and occasionally six-coordinate. The ligand-field strength of the donors is an important factor; weaker ligands may lead to an increased coordination number (Baker et al., 1970). Usually, the donor capacity of the ligands decreases in the following order en > phen > dmp (Kudrev, 1994).

Dialkyl dithiophosphates have extensive applications, such as antioxidants and antiwear additives in the rubber industry and in lubrication engineering (Kovtun et al., 1992; Harrison & Kikabhai, 1987), as well as flotation agents for mineral ores and solvent extraction reagents for metals (Haiduc et al., 1995; Rickelton & Boyle, 1990).

The reactions of copper(II) with the (RO)₂P(S)S^- ion and nitrogen base ligands have been investigated (Lawton et al., 1972; Yordanov et al., 1993; Drew et al., 1987). These copper(II) complexes can cause DNA damage in the presence of H₂O₂. It was reported that Cu^II(en)₂ (en is ethylenediamine) and hydrogen peroxide at physiological conditions could cause the DNA strand to break (Ozawa et al., 1993). Additionally, Cu^II(en)₂ complexes may be used as good catalysts for all oxidizers, and the catalytic activities for all oxidizers decreased in the order Cu > Ni> Cd >> Zn (Sinditskii et al., 1994).

In order to investigate the properties of the (EtO)₂P(S)S^- ion complexed with Cu^II(en)₂, the title complex, (I), was synthesized and an X-ray crystal structure analysis undertaken.

The asymmetric unit of (I) consists one half of the complex molecule, and the unit cell contains two complexes. One half of the complex is related to the other by an inversion center at the Cu atom. The Cu atom is coordinated by four N atoms in a slightly distorted square coordination geometry. The Cu—N bond lengths are 2.016 (2) and 2.019 (2) Å, and the N—Cu—N bond angles are 84.6 (1) and 95.3 (1)°. The Cu—N values are normal for primary amines (Allen et al., 1987). The bond lengths and angles of the title complex are comparable with those in a previous report of the same complex (Pervukhina & Podbereskaya, 1985), but the structure was solved in the wrong space group, P2₁. However, intensity statistics, as well as systematic extinctions, clearly indicate the space group to be P2₁/c. The Cu—N bond lengths are in good agreement with those observed in Cu(en)[N(NO₂)CH₃]₂ [Cu—N = 2.019 (3) Å] (Palopoli et al., 1988), while the N—Cu—N angles are slightly outside the bite-angle range for ethylenediamine in Cu^II complexes, typically 85–86° (Palopoli et al., 1988).

The Cu^II–ethylenediamine complex molecule is not planar and adopts a twisted conformation. Atoms N1, N4, C2 and C3 deviate by 0.160 (2), -0.126 (2), -0.286 (3) and 0.267 (4) Å, respectively, from the mean plane of the Cu^II–ethylenediamine moiety, while the dihedral angle between the Cu1/N1/C2 and Cu1/N4/C3 planes is 19.5 (2)°.

In the (EtO)₂P(S)S^- anion, the P atom is coordinated tetrahedrally by two S atoms and two O atoms. The bond lengths around the P atom correspond to a P═S double bond and the P—O bond of an alkoxy O atom. The angles around the P atom are in the range 102.84 (11)–119.03 (5)°, implying a distorted tetrahedral coordination geometry for the P atom. The two ethoxy groups attached to the P atoms are nearly planar and make a dihedral angle of 86.3 (2)° with one another.

The crystal structure of the title complex is built from alternating molecular layers of Cu^II–ethylenediamine and (EtO)₂P(S)S^- stacked along the c axis. Atoms S1 and S2 are involved in intermolecular interactions with the amine groups. These interactions link the molecular layers into a three-dimensional arrangement.

S2. Experimental

The preparation of the title complex was divided into two steps. The first step was the preparation of Cu[(EtO)₂PS₂]₂, which followed the method of Drew et al. (1987). Cu[(EtO)₂PS₂]₂ was obtained as a brown solid and 5 mmol was dissolved in of ethanol (20 ml). The second step was the preparation of [Cu^IIen₂][(EtO)₂P(S)S–]₂. En (10 mmol) was added with stirring to an ethanol solution of Cu[(EtO)₂PS₂]₂. A deep-blue solution formed immediately. As the EtOH evaporated slowly, purple single crystals of [Cu^IIen₂][(EtO)₂P(S)S]₂ suitable for X-ray analysis were obtained.

S3. Refinement

After checking their presence in the difference map, all H atoms were fixed geometrically and allowed to ride on their parent C and N atoms in the refinement.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995) and PLATON (Spek, 1990).

Figures

Fig. 1. The structure of the title complex showing 50% probability displacement ellipsoids and the atom-numbering scheme.

Bis(ethylenediamine)copper(II) bis(O,O'-diethyl dithiophosphato-S,S')

Crystal data

[Cu(C2H8N2)](C4H10O2PS2)2	F(000) = 582
Mr = 554.22	Dx = 1.426 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
a = 14.6683 (3) Å	Cell parameters from 5321 reflections
b = 6.9409 (1) Å	θ = 1.5–28.3°
c = 13.5889 (1) Å	µ = 1.32 mm^−1
β = 111.157 (1)°	T = 293 K
V = 1290.25 (3) Å^3	Slab, purple
Z = 2	0.36 × 0.14 × 0.12 mm

Data collection

Siemens SMART CCD area-detector diffractometer	3144 independent reflections
Radiation source: fine-focus sealed tube	2125 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.089
Detector resolution: 8.33 pixels mm^-1	θmax = 28.3°, θmin = 1.5°
ω scans	h = −19→11
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	k = −9→9
Tmin = 0.649, Tmax = 0.858	l = −15→18
8941 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) = 0.106	H-atom parameters constrained
S = 0.92	w = 1/[σ^2(Fo^2) + (0.0254P)^2] where P = (Fo^2 + 2Fc^2)/3
3144 reflections	(Δ/σ)max < 0.001
126 parameters	Δρmax = 0.55 e Å^−3
0 restraints	Δρmin = −1.14 e Å^−3

Special details

Experimental. The data collection covered over a hemisphere of reciprocal space by a combination of three sets of exposures; each set had a different ϕ angle (0, 88 and 180°) for the crystal and each exposure of 10 s covered 0.3° in ω. The crystal-to-detector distance was 4 cm and the detector swing angle was -35°. Crystal decay was monitored by repeating fifty initial frames at the end of data collection and analysing the intensity of duplicate reflections, and was found to be negligible.

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	0.0000	0.5000	0.0000	0.03526 (16)
P1	−0.21830 (5)	0.17834 (10)	0.02951 (6)	0.02969 (18)
S1	−0.11126 (6)	0.13620 (10)	−0.02282 (6)	0.0376 (2)
S2	−0.19133 (6)	0.31888 (11)	0.16269 (6)	0.0423 (2)
O1	−0.30857 (15)	0.2898 (3)	−0.05542 (15)	0.0394 (5)
O2	−0.26241 (15)	−0.0331 (3)	0.03245 (16)	0.0381 (5)
N1	0.03236 (19)	0.4767 (3)	0.15711 (18)	0.0413 (6)
H1A	0.0566	0.5888	0.1892	0.050*
H1B	−0.0218	0.4479	0.1705	0.050*
N4	0.1241 (2)	0.3484 (3)	0.0280 (2)	0.0420 (6)
H4A	0.1097	0.2279	0.0028	0.050*
H4B	0.1608	0.4046	−0.0046	0.050*
C2	0.1057 (3)	0.3217 (4)	0.1968 (3)	0.0486 (8)
H2B	0.0742	0.1966	0.1811	0.058*
H2A	0.1383	0.3327	0.2726	0.058*
C3	0.1782 (3)	0.3431 (5)	0.1430 (3)	0.0510 (9)
H3B	0.2153	0.4610	0.1658	0.061*
H3A	0.2234	0.2354	0.1609	0.061*
C7	−0.3500 (3)	0.2163 (5)	−0.1622 (2)	0.0528 (9)
H7A	−0.3744	0.0865	−0.1621	0.063*
H7B	−0.3007	0.2134	−0.1943	0.063*
C8	−0.4318 (3)	0.3484 (7)	−0.2227 (3)	0.0767 (13)
H8A	−0.4590	0.3073	−0.2949	0.115*
H8B	−0.4073	0.4774	−0.2195	0.115*
H8C	−0.4816	0.3452	−0.1923	0.115*
C5	−0.3477 (3)	−0.0558 (5)	0.0606 (3)	0.0540 (9)
H5A	−0.3992	0.0297	0.0183	0.065*
H5B	−0.3318	−0.0231	0.1343	0.065*
C6	−0.3810 (3)	−0.2565 (6)	0.0422 (4)	0.0790 (13)
H6A	−0.4420	−0.2693	0.0526	0.119*
H6B	−0.3331	−0.3390	0.0907	0.119*
H6C	−0.3895	−0.2925	−0.0288	0.119*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0420 (3)	0.0313 (3)	0.0356 (3)	0.0067 (2)	0.0178 (2)	−0.0020 (2)
P1	0.0313 (4)	0.0268 (3)	0.0340 (4)	0.0026 (3)	0.0154 (3)	0.0006 (3)
S1	0.0373 (4)	0.0298 (4)	0.0547 (5)	−0.0046 (3)	0.0273 (4)	−0.0086 (3)
S2	0.0510 (5)	0.0449 (4)	0.0357 (4)	0.0019 (4)	0.0213 (4)	−0.0054 (3)
O1	0.0394 (13)	0.0429 (11)	0.0358 (10)	0.0125 (10)	0.0134 (10)	0.0038 (9)
O2	0.0365 (12)	0.0320 (10)	0.0549 (12)	−0.0029 (9)	0.0276 (11)	0.0013 (9)
N1	0.0425 (16)	0.0434 (14)	0.0406 (14)	−0.0102 (12)	0.0182 (13)	−0.0078 (11)
N4	0.0443 (16)	0.0292 (12)	0.0570 (16)	0.0009 (11)	0.0236 (14)	−0.0004 (11)
C2	0.053 (2)	0.0439 (18)	0.0410 (17)	−0.0068 (16)	0.0069 (16)	0.0037 (14)
C3	0.0383 (19)	0.0412 (17)	0.064 (2)	0.0024 (15)	0.0076 (18)	0.0003 (15)
C7	0.049 (2)	0.064 (2)	0.0410 (18)	−0.0030 (18)	0.0111 (17)	−0.0003 (16)
C8	0.048 (2)	0.121 (4)	0.053 (2)	0.006 (2)	0.007 (2)	0.025 (2)
C5	0.046 (2)	0.060 (2)	0.071 (2)	−0.0054 (17)	0.039 (2)	0.0034 (18)
C6	0.053 (3)	0.064 (2)	0.130 (4)	−0.014 (2)	0.045 (3)	0.013 (3)

Geometric parameters (Å, º)

Cu1—N4^i	2.016 (2)	C2—H2B	0.9700
Cu1—N4	2.016 (2)	C2—H2A	0.9700
Cu1—N1	2.019 (2)	C3—H3B	0.9700
Cu1—N1^i	2.019 (2)	C3—H3A	0.9700
P1—O1	1.606 (2)	C7—C8	1.498 (5)
P1—O2	1.6098 (19)	C7—H7A	0.9700
P1—S1	1.9652 (10)	C7—H7B	0.9700
P1—S2	1.9664 (10)	C8—H8A	0.9600
O1—C7	1.449 (4)	C8—H8B	0.9600
O2—C5	1.442 (3)	C8—H8C	0.9600
N1—C2	1.478 (4)	C5—C6	1.467 (5)
N1—H1A	0.9000	C5—H5A	0.9700
N1—H1B	0.9000	C5—H5B	0.9700
N4—C3	1.477 (4)	C6—H6A	0.9600
N4—H4A	0.9000	C6—H6B	0.9600
N4—H4B	0.9000	C6—H6C	0.9600
C2—C3	1.500 (5)
N4^i—Cu1—N4	180.0	H2B—C2—H2A	108.5
N4^i—Cu1—N1	95.33 (10)	N4—C3—C2	108.3 (3)
N4—Cu1—N1	84.67 (10)	N4—C3—H3B	110.0
N4^i—Cu1—N1^i	84.67 (10)	C2—C3—H3B	110.0
N4—Cu1—N1^i	95.33 (10)	N4—C3—H3A	110.0
N1—Cu1—N1^i	180.00 (13)	C2—C3—H3A	110.0
O1—P1—O2	102.84 (11)	H3B—C3—H3A	108.4
O1—P1—S1	111.76 (8)	O1—C7—C8	107.3 (3)
O2—P1—S1	104.72 (8)	O1—C7—H7A	110.3
O1—P1—S2	105.20 (8)	C8—C7—H7A	110.3
O2—P1—S2	112.24 (8)	O1—C7—H7B	110.3
S1—P1—S2	119.03 (5)	C8—C7—H7B	110.3
C7—O1—P1	119.28 (19)	H7A—C7—H7B	108.5
C5—O2—P1	120.08 (19)	C7—C8—H8A	109.5
C2—N1—Cu1	107.85 (18)	C7—C8—H8B	109.5
C2—N1—H1A	110.1	H8A—C8—H8B	109.5
Cu1—N1—H1A	110.1	C7—C8—H8C	109.5
C2—N1—H1B	110.1	H8A—C8—H8C	109.5
Cu1—N1—H1B	110.1	H8B—C8—H8C	109.5
H1A—N1—H1B	108.4	O2—C5—C6	109.0 (3)
C3—N4—Cu1	108.47 (19)	O2—C5—H5A	109.9
C3—N4—H4A	110.0	C6—C5—H5A	109.9
Cu1—N4—H4A	110.0	O2—C5—H5B	109.9
C3—N4—H4B	110.0	C6—C5—H5B	109.9
Cu1—N4—H4B	110.0	H5A—C5—H5B	108.3
H4A—N4—H4B	108.4	C5—C6—H6A	109.5
N1—C2—C3	107.5 (2)	C5—C6—H6B	109.5
N1—C2—H2B	110.2	H6A—C6—H6B	109.5
C3—C2—H2B	110.2	C5—C6—H6C	109.5
N1—C2—H2A	110.2	H6A—C6—H6C	109.5
C3—C2—H2A	110.2	H6B—C6—H6C	109.5
O2—P1—O1—C7	−59.5 (2)	N1—Cu1—N4—C3	−12.11 (19)
S1—P1—O1—C7	52.3 (2)	N1^i—Cu1—N4—C3	167.89 (19)
S2—P1—O1—C7	−177.2 (2)	Cu1—N1—C2—C3	41.7 (3)
O1—P1—O2—C5	−58.8 (3)	Cu1—N4—C3—C2	38.3 (3)
S1—P1—O2—C5	−175.8 (2)	N1—C2—C3—N4	−53.3 (3)
S2—P1—O2—C5	53.7 (2)	P1—O1—C7—C8	−179.9 (2)
N4^i—Cu1—N1—C2	163.41 (19)	P1—O2—C5—C6	171.7 (3)
N4—Cu1—N1—C2	−16.59 (19)

Symmetry code: (i) −x, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···S2^ii	0.90	2.76	3.599 (2)	155
N1—H1B···S2	0.90	2.61	3.486 (3)	165
N4—H4A···S1^iii	0.90	2.54	3.368 (2)	153

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