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The title centrosymmetric CuII binuclear complex, bis([mu]-N,N-diethyl-1,1-di­seleno­carbamato-Se,Se':Se)­bis­[(N,N-diethyl-1,1-di­seleno­carbamato-Se,Se')copper(II)], [Cu(Se2CNEt2)2]2 or [Cu2(C5H10NSe2)4], is built from two symmetry-related [Cu{Se2CN(Et)2}2] units by pairs of Cu-Se bonds. The coordination geometry at the unique Cu atom is distorted square pyramidal, with Cu-Se distances in the range 2.4091 (11)-2.9095 (10) Å.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100005503/qb0207sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270100005503/qb0207Isup2.hkl
Contains datablock I

Comment top

In sharp contrast to many studies on the chemistry of metal complexes with 1,1-dithiolate ligands, the chemistry of metal complexes with 1,1-diselenolate ligands has received scant attention. Although the 2,2-dicyanoethylence-1,1-diselenolate and N,N-diethyl-1,1-diselenocarbamate ligands were prepared many years ago (Jensen & Henriksen, 1970; Barnard et al., 1961), to our surprise, there are very few papers referring to such diselenolate ligands, among which the investigation was focused on the spectroscopic properties (Jensen & Krishnan, 1970), and very few crystal structures, such as bis(tetra-n-butylammonium) bis(2,2-dicyanoethylene-1,1-diselenolato)selenium(II) (Hummel et al., 1992) and selenium bis(1-pyrrolidinecarbodiselenoate) (Esperas et al., 1975), have been determined.

Current research interest is directed towards the understanding of the activation and cleavage of C—S and C—Se bonds in transition metal complexes featuring thiolate ligands (Hong et al., 1998; Cao et al., 1994; Jiang et al., 1993). In an attempt to observe how the C—Se bonds were activated by transition metal active centers, we prepared a series of complex containing N,N-diethyl-1,1-diselenocarbamate ligands. Herein we report a centrosymmetric binuclear CuII complex, [Cu{Se2CN(Et)2}2]2, which was prepared from the reaction of CuSO4 and Se[{Se2CN(Et)2}2]2 in THF. Each bivalent Cu atom in the complex is coordinated by two N,N-diethyl-1,1-diselenocarbamate ligands in a distorted square-planar geometry forming a [Cu{Se2CN(Et)2}2] unit. Two such units are linked by Cu—Se bonds to form the binuclear complex. Thus, the coordination geometry of each Cu atom is distorted square pyramidal with CuSe5. N,N-Diethyl-1,1-diselenocarbamate acts as a chelating ligand to coordinate the Cu atom with an Se—Cu—Se angle of 79.04 (5)°. Two kinds of Cu—Se bonds are present in the complex: the shorter are in the range 2.4091 (11)–2.4455 (8) Å (average 2.428 Å) and the longer is 2.9095 (10) Å. The shorter average is compatible withthose found in the related compounds of bis(tetra-n-butyl) bis(1,1-dicyanoethene-2,2-diselenolato-Se,Se')nitridotechnetium(V) (Abram et al., 1991) and bis(tetraphenylarsonium) tris(2,2-diselenido-1,1-ethylenedicarbonitrile)nickel(IV) (Kaiser at al., 1980)

Experimental top

The title compound was obtained from the reaction of CuSO4 and and Se[{Se2CN(Et)2}2]2 (molar ratio 1:1) in THF. To a solution of Se[{Se2CN(Et)2}2]2 (0.69 g, 1 mmol) in THF (20 ml) was added solid CuSO4 (0.15 g, 1 mmol). The reaction solution turned brown–red gradually. After stirring for 2 h, the brown–red solution was filtered. The filtrate was kept in an icebox for one week to yield brown–red prisms of the title complex. Crystals suitable for X-ray diffraction analysis were obtained by recrystallization from THF/hexane at room temperature.

Computing details top

Data collection: SMART CCD Software (Siemens, 1994); cell refinement: SMART CCD Software; data reduction: SMART CCD Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); software used to prepare material for publication: SHELXL97.

(I) top
Crystal data top
[Cu2(C5H10NSe2)4]F(000) = 1036
Mr = 1095.32Dx = 2.158 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 9.825 (2) ÅCell parameters from 397 reflections
b = 10.904 (2) Åθ = 12.6–19.8°
c = 16.051 (3) ŵ = 9.92 mm1
β = 101.44 (3)°T = 293 K
V = 1685.4 (6) Å3Prism, brown–red
Z = 20.29 × 0.24 × 0.22 mm
Data collection top
SMART CCD
diffractometer
2929 independent reflections
Radiation source: fine-focus sealed tube2474 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.036
ω scansθmax = 25.0°, θmin = 2.3°
Absorption correction: empirical (using intensity measurements)
empirical (using intensity measurements) from equivalent reflections (XEMP in SHELXTL; Sheldrick, 1994)
h = 1011
Tmin = 0.168, Tmax = 0.269k = 712
7952 measured reflectionsl = 1916
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.032H-atom parameters constrained
wR(F2) = 0.086 w = 1/[σ2(Fo2) + (0.0439P)2 + 0.5791P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max = 0.001
2929 reflectionsΔρmax = 1.10 e Å3
155 parametersΔρmin = 0.71 e Å3
0 restraintsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0090 (4)
Crystal data top
[Cu2(C5H10NSe2)4]V = 1685.4 (6) Å3
Mr = 1095.32Z = 2
Monoclinic, P21/nMo Kα radiation
a = 9.825 (2) ŵ = 9.92 mm1
b = 10.904 (2) ÅT = 293 K
c = 16.051 (3) Å0.29 × 0.24 × 0.22 mm
β = 101.44 (3)°
Data collection top
SMART CCD
diffractometer
2929 independent reflections
Absorption correction: empirical (using intensity measurements)
empirical (using intensity measurements) from equivalent reflections (XEMP in SHELXTL; Sheldrick, 1994)
2474 reflections with I > 2σ(I)
Tmin = 0.168, Tmax = 0.269Rint = 0.036
7952 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0320 restraints
wR(F2) = 0.086H-atom parameters constrained
S = 1.08Δρmax = 1.10 e Å3
2929 reflectionsΔρmin = 0.71 e Å3
155 parameters
Special details top

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 structure was solved by direct methods. All non-H atoms were refined with anisotropic displacement parameters. The positions of all hydrogen atoms were generated geometrically (C—H bond fixed at 0.96 Å), assigned isotropic thermal parameters, and allowed to ride on their respective parent C atoms before the final cycle of least-squares refinement. All calculations were performed on an HP586 computer with SHELXTL-PC program package.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Se10.31466 (6)1.03643 (5)0.04538 (4)0.0489 (2)
Se20.04096 (5)1.16813 (4)0.03164 (3)0.03191 (17)
Se30.00877 (5)0.94118 (4)0.20712 (3)0.03416 (17)
Se40.23439 (6)0.78374 (5)0.11099 (3)0.03993 (18)
Cu0.12829 (6)0.96820 (5)0.06600 (4)0.03389 (19)
N10.2442 (4)1.2686 (4)0.1006 (3)0.0315 (9)
N20.0955 (5)0.7344 (4)0.2780 (3)0.0395 (10)
C110.2063 (5)1.1761 (4)0.0490 (3)0.0281 (10)
C120.3773 (6)1.2730 (5)0.1600 (3)0.0436 (13)
H12A0.41381.35480.16150.080*
H12B0.44151.21950.13990.080*
C130.3664 (7)1.2375 (6)0.2470 (4)0.0650 (18)
H13A0.45631.24150.28370.080*
H13B0.30381.29180.26780.080*
H13C0.33181.15510.24600.080*
C140.1531 (6)1.3751 (5)0.1030 (4)0.0463 (14)
H14A0.16201.40240.16070.080*
H14B0.05861.35040.08270.080*
C150.1873 (8)1.4802 (6)0.0509 (5)0.077 (2)
H15A0.12631.54830.05320.080*
H15B0.28161.50520.07180.080*
H15C0.17731.45280.00690.080*
C210.1053 (5)0.8055 (4)0.2113 (3)0.0321 (11)
C220.1843 (7)0.6236 (5)0.2760 (4)0.0556 (16)
H22A0.27260.63890.23960.080*
H22B0.19960.60580.33200.080*
C230.1207 (7)0.5152 (5)0.2410 (5)0.0667 (19)
H23A0.17820.44370.23900.080*
H23B0.10630.53350.18480.080*
H23C0.03280.50020.27790.080*
C240.0027 (6)0.7576 (5)0.3582 (4)0.0540 (16)
H24A0.08320.79910.34680.080*
H24B0.03220.68090.38520.080*
C250.0599 (8)0.8345 (7)0.4181 (4)0.074 (2)
H25A0.00530.84880.47020.080*
H25B0.08820.91160.39130.080*
H25C0.13980.79250.43010.080*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Se10.0473 (4)0.0337 (3)0.0542 (4)0.0133 (2)0.0179 (3)0.0155 (2)
Se20.0382 (3)0.0273 (3)0.0264 (3)0.0043 (2)0.0029 (2)0.00270 (18)
Se30.0430 (3)0.0273 (3)0.0290 (3)0.0050 (2)0.0005 (2)0.00396 (19)
Se40.0419 (3)0.0379 (3)0.0374 (3)0.0110 (2)0.0014 (2)0.0057 (2)
Cu0.0425 (4)0.0274 (4)0.0280 (3)0.0042 (3)0.0022 (3)0.0070 (2)
N10.032 (2)0.027 (2)0.034 (2)0.0019 (17)0.0022 (18)0.0060 (17)
N20.047 (3)0.035 (3)0.037 (2)0.004 (2)0.010 (2)0.0083 (19)
C110.033 (3)0.025 (3)0.024 (2)0.003 (2)0.001 (2)0.0009 (18)
C120.039 (3)0.041 (3)0.046 (3)0.008 (2)0.002 (3)0.015 (2)
C130.067 (4)0.077 (5)0.043 (4)0.007 (4)0.007 (3)0.008 (3)
C140.048 (3)0.034 (3)0.056 (4)0.007 (3)0.007 (3)0.016 (3)
C150.071 (5)0.039 (4)0.115 (7)0.003 (3)0.006 (4)0.006 (4)
C210.040 (3)0.023 (3)0.035 (3)0.005 (2)0.013 (2)0.006 (2)
C220.068 (4)0.046 (4)0.057 (4)0.016 (3)0.021 (3)0.020 (3)
C230.081 (5)0.034 (4)0.081 (5)0.014 (3)0.007 (4)0.009 (3)
C240.060 (4)0.055 (4)0.041 (3)0.002 (3)0.005 (3)0.022 (3)
C250.097 (6)0.087 (6)0.040 (4)0.013 (4)0.017 (4)0.002 (3)
Geometric parameters (Å, º) top
Se1—C111.866 (5)N1—C111.311 (6)
Se1—Cu2.4091 (11)N1—C121.458 (6)
Se2—C111.867 (5)N1—C141.472 (6)
Se2—Cu2.4455 (8)N2—C211.310 (6)
Se2—Cui2.9095 (10)N2—C241.470 (7)
Se3—C211.865 (5)N2—C221.487 (7)
Se3—Cu2.4127 (11)C12—C131.474 (8)
Se4—C211.856 (5)C14—C151.496 (9)
Se4—Cu2.4397 (8)C22—C231.498 (9)
Cu—Se2i2.9095 (10)C24—C251.496 (8)
C11—Se1—Cu85.45 (14)C11—N1—C12122.9 (4)
C11—Se2—Cu84.37 (14)C11—N1—C14121.7 (4)
C11—Se2—Cui99.31 (14)C12—N1—C14115.3 (4)
Cu—Se2—Cui85.96 (3)C21—N2—C24122.9 (4)
C21—Se3—Cu84.43 (15)C21—N2—C22121.1 (5)
C21—Se4—Cu83.84 (14)C24—N2—C22116.0 (4)
Se1—Cu—Se3159.22 (4)N1—C11—Se1123.7 (4)
Se1—Cu—Se499.65 (3)N1—C11—Se2124.9 (4)
Se3—Cu—Se479.23 (3)Se1—C11—Se2111.3 (2)
Se1—Cu—Se278.84 (3)N1—C12—C13112.8 (5)
Se3—Cu—Se299.51 (3)N1—C14—C15112.6 (5)
Se4—Cu—Se2172.43 (3)N2—C21—Se4124.0 (4)
Se1—Cu—Se2i100.93 (3)N2—C21—Se3123.5 (4)
Se3—Cu—Se2i99.85 (3)Se4—C21—Se3112.5 (2)
Se4—Cu—Se2i93.53 (3)N2—C22—C23111.3 (5)
Se2—Cu—Se2i94.04 (3)N2—C24—C25112.2 (5)
Symmetry code: (i) x, y+2, z.

Experimental details

Crystal data
Chemical formula[Cu2(C5H10NSe2)4]
Mr1095.32
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)9.825 (2), 10.904 (2), 16.051 (3)
β (°) 101.44 (3)
V3)1685.4 (6)
Z2
Radiation typeMo Kα
µ (mm1)9.92
Crystal size (mm)0.29 × 0.24 × 0.22
Data collection
DiffractometerSMART CCD
diffractometer
Absorption correctionEmpirical (using intensity measurements)
empirical (using intensity measurements) from equivalent reflections (XEMP in SHELXTL; Sheldrick, 1994)
Tmin, Tmax0.168, 0.269
No. of measured, independent and
observed [I > 2σ(I)] reflections
7952, 2929, 2474
Rint0.036
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.032, 0.086, 1.08
No. of reflections2929
No. of parameters155
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)1.10, 0.71

Computer programs: SMART CCD Software (Siemens, 1994), SMART CCD Software, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXL97.

Selected geometric parameters (Å, º) top
Se1—C111.866 (5)Se3—C211.865 (5)
Se1—Cu2.4091 (11)Se3—Cu2.4127 (11)
Se2—C111.867 (5)Se4—C211.856 (5)
Se2—Cu2.4455 (8)Se4—Cu2.4397 (8)
Se2—Cui2.9095 (10)Cu—Se2i2.9095 (10)
C11—Se1—Cu85.45 (14)Se1—Cu—Se278.84 (3)
C11—Se2—Cu84.37 (14)Se3—Cu—Se299.51 (3)
C11—Se2—Cui99.31 (14)Se4—Cu—Se2172.43 (3)
Cu—Se2—Cui85.96 (3)Se1—Cu—Se2i100.93 (3)
C21—Se3—Cu84.43 (15)Se3—Cu—Se2i99.85 (3)
C21—Se4—Cu83.84 (14)Se4—Cu—Se2i93.53 (3)
Se1—Cu—Se3159.22 (4)Se2—Cu—Se2i94.04 (3)
Se1—Cu—Se499.65 (3)Se1—C11—Se2111.3 (2)
Se3—Cu—Se479.23 (3)Se4—C21—Se3112.5 (2)
Symmetry code: (i) x, y+2, z.
 

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