A centrosymmetric hydro­xo bridged penta­methyl­di­ethyl­enetri­amine copper(II) complex, {[(pmdeta)Cu(OH)]2}2+·2Br−·2MeCN

Acta Cryst.(2001). E57, m365±m367 DOI: 10.1107/S1600536801011928 Guido Kickelbick [Cu₂(OH)₂(C₉H₂₃N₃)₂]Br₂2C₂H₃N

m365

metal-organic papers

Acta Crystallographica Section E

Structure Reports Online

ISSN 1600-5368

A centrosymmetric hydroxo-bridged

pentamethyl-diethylenetriamine copper(II) complex,

{[(pmdeta)-Cu(OH)]

}

2Br

2MeCN

Guido Kickelbick

Institut fuÈr Anorganische Chemie, Technische UniversitaÈt Wien, Getreidemarkt 9/153, A-1060 Wien, Austria

Correspondence e-mail: kickelgu@mail.zserv.tuwien.ac.at

Key indicators

Single-crystal X-ray study T= 293 K

Mean(C±C) = 0.006 AÊ Rfactor = 0.031 wRfactor = 0.080

Data-to-parameter ratio = 17.3

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

#2001 International Union of Crystallography Printed in Great Britain ± all rights reserved

The title compound, di-

-hydroxo-bis[(1,1,4,7,7-pentamethyl-diethylenetriamine)copper(II)] dibromide acetonitrile disol-vate, [Cu2(OH)2(C9H23N3)2]Br22CH3CN, is the reaction

product of CuBr with 1,1,4,7,7-pentamethyldiethylenetri-amine (pmdeta) in water-containing acetonitrile. The cation is the dimer of an asymmetrically hydroxo-bridged complex of copper(II) coordinated by 1,1,4,7,7-pentamethyldiethylenetri-amine. The centrosymmetric structure contains distorted square-pyramidally coordinated Cu atoms.

Comment

Di--hydroxo-bridged complexes of transition metals are a

widely known structural type. Due to the rather small bridging ligands, there is often the possibility of a metal±metal inter-action. If this takes place, a spin±spin interaction is possible when unpaired electrons are present, which makes such mol-ecules interesting model compounds for spin-coupling phenomena.

The complex described in this study, (I) has two CuII_centers

with a separation of 3.0022 (7) AÊ. The asymmetric unit of the crystal contains only half of the cation. Therefore, a centro-symmetric dimeric structure is obtained (Fig. 1). The bromide counter-ions as well as the acetonitrile molecules included in the crystal do not show any interactions with the copper centers, as illustrated in the packing diagram (Fig. 2).

Although the compound was synthesized from a CuI_halide,

the structure contains CuII_{ions. A possible explanation for the}

oxidation process is a disproportionation reaction which is

known for CuI_{amine complexes. This structure is related to}

another (pmdeta)CuII _{compound bridged by two hydroxo}

ligands, which contains perchlorate as the anion (Scottet al., 1995). This related complex also shows a distorted square pyramidal coordination sphere around the Cu atoms and two hydroxo bridges with CuÐO distances [1.964 (4) and 1.893 (5) AÊ] similar to those in the present structure [1.904 (2)

metal-organic papers

m366

and 1.988 (2) AÊ]. This bonding situation seems to be common

in this type of CuII _{complex and was also observed in the}

hydroxo-bridged cyclic triamine CuII _{compounds N,N}0_,N00

-trimethyl-1,4,7-triazacyclononane [CuÐO 1.936 (4) and 1.939 (4) AÊ; Chaudhuri et al., 1985], N -4-but-1-ene-1,4,7-tri-azacyclononane [CuÐO 1.929 (2) AÊ; Farrugiaet al., 1996] and other triazacyclononane complexes with different substitution patterns (Mahapatraet al., 1996). A special feature of the title

compound is its distortion of the square-pyramidal coordina-tion sphere. None of the above related structures displays such large differences in the equatorial CuÐN distances [CuÐ Nequatorial 2.040 (3) and 2.137 (3) AÊ; CuÐNaxial 2.340 (2) AÊ].

While usually the equatorial N atoms have the same distances to the Cu atom (within experimental uncertainties), the difference of the CuÐN distances in the title compound is nearly 0.1 AÊ.

Experimental

CuBr (4.53 g, 0.0316 mol) was suspended under stirring in water-saturated acetonitrile (50 ml) under an argon atmosphere in a Schlenk ¯ask. Pentamethlyethylenediamine (5.48 g, 0.0316 mol) was slowly added and the mixture was heated to 323 K for 15 min. The solution was cooled to room temperature and was allowed to stand for two weeks. The solvent was evaporated and dark-green crystals were isolated.

Crystal data

[Cu2(OH)2(C9H23N3)2]Br22C2H3N

Mr= 749.64

Monoclinic,P21/c

a= 9.2580 (5) AÊ

b= 10.9165 (6) AÊ

c= 16.4073 (8) AÊ = 91.543 (1) V= 1657.60 (15) AÊ3

Z= 2

Dx= 1.502 Mg mÿ3

MoKradiation Cell parameters from 5499

re¯ections = 2.7±24.2

= 3.72 mmÿ1

T= 293 (2) K Irregular, green 0.280.240.18 mm Data collection

Siemens SMART CCD area-detector diffractometer !scans

Absorption correction: multi-scan (SADABS; Sheldrick, 1996)

Tmin= 0.390,Tmax= 0.512 4696 measured re¯ections

2820 independent re¯ections 2389 re¯ections withI> 2(I)

Rint= 0.030 max= 24.7

h=ÿ10!10

k=ÿ12!12

l=ÿ19!19 Re®nement

Re®nement onF2

R[F2_{> 2(F}2_{)] = 0.031}

wR(F2_{) = 0.080}

S= 1.07 2820 re¯ections 163 parameters

H-atom parameters constrained

w= 1/[2_(F

o2) + (0.0471P)2

+ 0.5272P]

whereP= (Fo2+ 2Fc2)/3

(/)max= 0.001

max= 0.49 e AÊÿ3

min=ÿ0.56 e AÊÿ3

Table 1

Selected geometric parameters (AÊ,_).

Cu1ÐO1 1.904 (2) Cu1ÐO1i _{1.988 (2)} Cu1ÐN4 2.040 (3)

Cu1ÐN7 2.137 (3) Cu1ÐN1 2.340 (2) Cu1ÐCu1i _{3.0022 (7)}

O1ÐCu1ÐO1i _{79.06 (9)} O1ÐCu1ÐN4 174.48 (9) O1i_{ÐCu1ÐN4 97.15 (9)} O1ÐCu1ÐN7 100.16 (9) O1i_{ÐCu1ÐN7 146.06 (9)} N4ÐCu1ÐN7 85.23 (10)

O1ÐCu1ÐN1 95.09 (9) O1i_{ÐCu1ÐN1 103.15 (9)} N4ÐCu1ÐN1 81.80 (10) N7ÐCu1ÐN1 110.67 (9) Cu1ÐO1ÐCu1i _{100.94 (9)}

Symmetry code: (i) 1ÿx;1ÿy;1ÿz.

H atoms were located by difference Fourier maps and re®ned with a riding model.

Data collection:SMART(Bruker, 1997); cell re®nement:SAINT

(Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne

Figure 2

Projection of the structure along [100], showing ellipsoids at the 50% probability level. For clarity, H atoms have been omitted.

Figure 1

structure: SHELXL97 (Sheldrick, 1997); molecular graphics:

SHELXTL (Bruker, 1998); software used to prepare material for publication:SHELXL97.

References

Bruker (1997).SMARTandSAINT. Bruker AXS Inc., Madison, Wisconsin, USA.

Bruker (1998). SHELXTL. Version 5.1. Bruker AXS Inc., Madison, Wisconsin, USA.

Chaudhuri, P., Ventur, D., Wieghardt, K., Peters, E.-M., Peters, K. & Simon A. (1985).Angew. Chem. Int. Ed. Engl.24, 57±58.

Farrugia, L. J., Lovatt, P. A. & Peacock, R. D. (1996).Inorg. Chim. Acta,246, 343±348.

Mahapatra, S., Halfen, J. A., Wilkinson, E. C., Pan, G.-F., Wang, X.-D., Young, V. G. Jr, Cramer, C. J., Que, L. Jr & Tolman, W. B. (1996).J. Am. Chem. Soc. 118, 11555±11574.

Scott, M. J., Zhang, H. H., Lee, S. C., Hedman, B., Hodgson, K. O. & Holm, R. H. (1995).J. Am. Chem. Soc.117, 568±569.

Sheldrick, G. M. (1996).SADABS. University of GoÈttingen, Germany. Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of

GoÈttingen, Germany.

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Acta Cryst. (2001). E57, m365–m367 [doi:10.1107/S1600536801011928]

A centrosymmetric hydroxo-bridged pentamethyldiethylenetriamine copper(II)

complex, {[(pmdeta)Cu(OH)]

}

·

2Br

·

2MeCN

Guido Kickelbick

S1. Comment

Di-µ-hydroxo-bridged complexes of transition metals are a widely known structural type. Due to the rather small

bridging ligands, there is often the possibility of a metal–metal interaction. If this takes place, a spin–spin interaction is

possible when unpaired electrons are present, which makes such molecules interesting model compounds for

spin-coupling phenomena.

The complex described in this study, (I) has two CuII _{centers with a separation of 3.0022 (7) Å. The asymmetric unit of}

the crystal contains only half of the cation. Therefore, a centrosymmetric dimeric structure is obtained (Fig. 1). The

bromide counter-ions as well as the acetonitrile molecules included in the crystal do not show any interactions with the

copper centers, as illustrated in the packing diagram (Fig. 2). Although the compound was synthesized from a CuI _halide,

the structure contains CuII _{ions. A possible explanation for the oxidation process is a disproportionation reaction which is}

known for CuI _{amine complexes. This structure is related to another (pmdeta)Cu}II _{compound bridged by two hydroxo}

ligands, which contains perchlorate as the anion (Scott et al., 1995). This related complex also shows a distorted square

pyramidal coordination sphere around the Cu atoms and two hydroxo bridges with similar Cu—O distances [1.964 (4)

and 1.893 (5) Å] to those in the present structure [1.904 (2) and 1.988 (2) Å]. This bonding situation seems to be common

in this type of CuII _{complex and was also observed in the hydroxo-bridged cyclic triamine Cu}II _{compoounds N,N′,N}

′′-tri-methyl-1,4,7-triazacyclononane [Cu—O 1.936 (4) and 1.939 (4) Å] (Chaudhuri et al., 1985), N

-4-but-1-ene-1,4,7-triaza-cyclononane [Cu—O 1.929 (2) Å; Farrugia et al., 1996] and other triazacyclononane complexes with different

substitution patterns (Mahapatra et al., 1996). A special feature of the title compound is its distortion of the

square-pyramidal coordination sphere. None of the above related structures displays such large differences in the equatorial Cu

—N distances [Cu—Nequatorial 2.040 (3) and 2.137 (3) Å; Cu—Naxial 2.340 (2) Å]. While usually the equatorial N atoms

have the same distances to the Cu atom (within experimental uncertainties), the difference of the Cu—N distances in the

title compound is nearly 0.1 Å.

S2. Experimental

CuBr (4.53 g, 0.0316 mol) was suspended under stirring in water-saturated acetonitrile (50 ml) under an argon

atmosphere in a Schlenk flask. Pentamethlyethylenediamine (5.48 g, 0.0316 mol) was slowly added and the mixture was

heated to 323 K for 15 min. The solution was cooled to room temperature and was allowed to stand for two weeks. The

solvent was evaporated and dark-green crystals were isolated.

S3. Refinement

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Figure 1

The structure of the dimeric cation with ellipsoids at the 50% probability level. The asymmetric unit contains also one Br

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Figure 2

Projection of the structure along [100], showing ellipsoids at the 50% probability level. For clarity, H atoms have been

omitted.

Di-µ-hydroxo-bis[(1,1,4,7,7-pentamethyldiethylenetriamine)copper(II)] dibromide acetonitrile solvate

Crystal data

[Cu2(OH)2(C9H23N3)2]Br2·2C2H3N

Mr = 749.64 Monoclinic, P21/c

a = 9.2580 (5) Å b = 10.9165 (6) Å c = 16.4073 (8) Å β = 91.543 (1)° V = 1657.60 (15) Å3

Z = 2

F(000) = 772 Dx = 1.502 Mg m−3

Mo Kα radiation, λ = 0.71073 Å Cell parameters from 5499 reflections θ = 2.7–24.2°

µ = 3.72 mm−1

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Data collection

Siemens SMART CCD area-detector diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

ω scans

Absorption correction: multi-scan (SADABS; Sheldrick, 1996) Tmin = 0.390, Tmax = 0.512

4696 measured reflections 2820 independent reflections 2389 reflections with I > 2σ(I) Rint = 0.030

θmax = 24.7°, θmin = 2.2°

h = −10→10 k = −12→12 l = −19→19

Refinement Refinement on F2 Least-squares matrix: full R[F2 _{> 2σ(F}2_{)] = 0.031}

wR(F2_{) = 0.080}

S = 1.07 2820 reflections 163 parameters 0 restraints

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

Hydrogen site location: inferred from neighbouring sites

H-atom parameters constrained w = 1/[σ2_(F

o2) + (0.0471P)2 + 0.5272P] where P = (Fo2 + 2Fc2)/3

(Δ/σ)max = 0.001 Δρmax = 0.49 e Å−3 Δρmin = −0.56 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 F}2_, conventional R-factors R are based on F, with F set to zero for negative F2_{. The threshold expression of F}2 _{> σ(F}2_{) 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 (Å2₎

x y z Uiso*/Ueq

Cu1 0.46441 (4) 0.39316 (3) 0.55344 (2) 0.02289 (12)

Br1 0.18594 (4) 0.35368 (3) 0.302589 (19) 0.03915 (13)

O1 0.5469 (2) 0.5525 (2) 0.56219 (12) 0.0288 (5)

H1 0.5827 0.5937 0.6081 0.035*

N1 0.2395 (3) 0.4504 (2) 0.60299 (15) 0.0287 (6)

C2 0.1529 (3) 0.3378 (3) 0.5993 (2) 0.0372 (8)

H2A 0.0520 0.3587 0.5901 0.045*

H2B 0.1619 0.2951 0.6511 0.045*

C3 0.2014 (3) 0.2548 (3) 0.5320 (2) 0.0355 (8)

H3A 0.1494 0.1778 0.5349 0.043*

H3B 0.1775 0.2923 0.4798 0.043*

N4 0.3605 (3) 0.2298 (2) 0.53732 (14) 0.0273 (6)

C5 0.3971 (4) 0.1528 (3) 0.6091 (2) 0.0358 (8)

H5A 0.3767 0.0675 0.5967 0.043*

H5B 0.3388 0.1769 0.6547 0.043*

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H6A 0.5775 0.1215 0.6807 0.045*

H6B 0.6128 0.1359 0.5880 0.045*

N7 0.5894 (3) 0.2993 (2) 0.64528 (15) 0.0297 (6)

C8 0.2346 (4) 0.5087 (4) 0.6837 (2) 0.0525 (10)

H8A 0.2926 0.5816 0.6840 0.079*

H8B 0.2714 0.4530 0.7244 0.079*

H8C 0.1365 0.5297 0.6952 0.079*

C9 0.1864 (4) 0.5409 (3) 0.5434 (2) 0.0381 (8)

H9A 0.1885 0.5063 0.4896 0.057*

H9B 0.2467 0.6123 0.5460 0.057*

H9C 0.0890 0.5632 0.5555 0.057*

C10 0.4042 (4) 0.1670 (3) 0.4617 (2) 0.0381 (8)

H10A 0.3800 0.2175 0.4154 0.057*

H10B 0.3544 0.0902 0.4567 0.057*

H10C 0.5066 0.1528 0.4639 0.057*

C11 0.5478 (4) 0.3389 (4) 0.7273 (2) 0.0434 (9)

H11A 0.4452 0.3304 0.7323 0.065*

H11B 0.5745 0.4231 0.7353 0.065*

H11C 0.5965 0.2891 0.7676 0.065*

C12 0.7476 (3) 0.3144 (3) 0.6404 (2) 0.0375 (8)

H12A 0.7781 0.2894 0.5875 0.056*

H12B 0.7949 0.2649 0.6814 0.056*

H12C 0.7724 0.3989 0.6492 0.056*

N30 0.8180 (5) 0.1151 (4) 0.4675 (3) 0.0782 (13)

C31 0.8957 (5) 0.0926 (4) 0.4187 (3) 0.0498 (10)

C32 0.9964 (5) 0.0606 (5) 0.3563 (3) 0.0697 (14)

H31A 0.9487 0.0100 0.3160 0.105*

H31B 1.0766 0.0168 0.3805 0.105*

H31C 1.0307 0.1339 0.3309 0.105*

Atomic displacement parameters (Å2₎

U11 _U22 _U33 _U12 _U13 _U23

Cu1 0.0180 (2) 0.0242 (2) 0.0265 (2) −0.00388 (14) 0.00106 (14) 0.00275 (15) Br1 0.0412 (2) 0.0443 (2) 0.03174 (19) −0.00103 (15) −0.00168 (14) −0.00340 (14) O1 0.0307 (12) 0.0293 (12) 0.0263 (10) −0.0101 (9) −0.0027 (9) 0.0004 (9) N1 0.0195 (13) 0.0356 (16) 0.0312 (13) 0.0002 (11) 0.0032 (10) −0.0001 (12)

C2 0.0212 (17) 0.045 (2) 0.0455 (19) −0.0008 (14) 0.0048 (14) 0.0112 (16)

C3 0.0234 (17) 0.039 (2) 0.0436 (19) −0.0115 (14) −0.0014 (14) 0.0021 (16)

N4 0.0256 (14) 0.0276 (14) 0.0287 (13) −0.0041 (11) 0.0013 (11) 0.0033 (11) C5 0.0390 (19) 0.0301 (18) 0.0383 (18) −0.0062 (15) −0.0004 (15) 0.0052 (15)

C6 0.0332 (19) 0.0302 (19) 0.048 (2) −0.0003 (14) −0.0020 (15) 0.0111 (15)

N7 0.0238 (14) 0.0303 (15) 0.0350 (14) −0.0028 (11) −0.0014 (11) 0.0051 (12)

C8 0.047 (2) 0.067 (3) 0.044 (2) 0.014 (2) 0.0021 (17) −0.0119 (19)

C9 0.0249 (17) 0.038 (2) 0.051 (2) 0.0033 (14) 0.0054 (14) 0.0062 (17)

C10 0.048 (2) 0.0298 (19) 0.0362 (18) −0.0031 (15) 0.0049 (15) −0.0047 (15)

C11 0.038 (2) 0.057 (2) 0.0355 (19) 0.0033 (17) 0.0023 (15) 0.0035 (17)

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N30 0.074 (3) 0.069 (3) 0.093 (3) −0.015 (2) 0.032 (2) −0.024 (2)

C31 0.048 (2) 0.043 (2) 0.058 (2) −0.0175 (19) 0.004 (2) −0.009 (2)

C32 0.072 (3) 0.082 (3) 0.056 (3) −0.028 (3) 0.019 (2) −0.019 (2)

Geometric parameters (Å, º)

Cu1—O1 1.904 (2) C2—C3 1.506 (5)

Cu1—O1i _{1.988 (2) C3—N4 1.498 (4)}

Cu1—N4 2.040 (3) N4—C5 1.480 (4)

Cu1—N7 2.137 (3) N4—C10 1.484 (4)

Cu1—N1 2.340 (2) C5—C6 1.503 (5)

Cu1—Cu1i _{3.0022 (7) C6—N7 1.487 (4)}

O1—Cu1i _{1.988 (2) N7—C11 1.474 (4)}

N1—C9 1.466 (4) N7—C12 1.478 (4)

N1—C2 1.468 (4) N30—C31 1.119 (5)

N1—C8 1.471 (4) C31—C32 1.446 (6)

O1—Cu1—O1i _{79.06 (9) C2—N1—Cu1 104.63 (19)}

O1—Cu1—N4 174.48 (9) C8—N1—Cu1 118.6 (2)

O1i_{—Cu1—N4 97.15 (9) N1—C2—C3 111.1 (3)}

O1—Cu1—N7 100.16 (9) N4—C3—C2 112.3 (3)

O1i_{—Cu1—N7 146.06 (9) C5—N4—C10 110.0 (3)}

N4—Cu1—N7 85.23 (10) C5—N4—C3 110.7 (2)

O1—Cu1—N1 95.09 (9) C10—N4—C3 109.0 (2)

O1i_{—Cu1—N1 103.15 (9) C5—N4—Cu1 107.25 (18)}

N4—Cu1—N1 81.80 (10) C10—N4—Cu1 111.95 (19)

N7—Cu1—N1 110.67 (9) C3—N4—Cu1 107.94 (19)

O1—Cu1—Cu1i _{40.55 (6) N4—C5—C6 109.4 (3)}

O1i_—Cu1—Cu1i _{38.51 (6) N7—C6—C5 110.3 (3)}

N4—Cu1—Cu1i _{135.53 (7) C11—N7—C12 107.5 (3)}

N7—Cu1—Cu1i _{131.39 (7) C11—N7—C6 111.2 (3)}

N1—Cu1—Cu1i _{101.94 (7) C12—N7—C6 108.1 (3)}

Cu1—O1—Cu1i _{100.94 (9) C11—N7—Cu1 110.6 (2)}

C9—N1—C2 111.3 (2) C12—N7—Cu1 115.3 (2)

C9—N1—C8 106.9 (3) C6—N7—Cu1 104.17 (19)

C2—N1—C8 111.7 (3) N30—C31—C32 178.6 (5)

C9—N1—Cu1 103.54 (18)