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The crystal structure of the title compound, [Cu2(C2F3O2)2(C10H8N3O)2]·2CH3CN, contains discrete [Cu2(CF3COO)2(O-dpa)2] mol­ecules (O-dpaH is di-2-pyridyl­amine 1-oxide) which have imposed crystallographic twofold symmetry and an aceto­nitrile mol­ecule of solvation. The O-dpa ligand is both bidentate and bridging, linking two Cu atoms with a separation of 3.4270 (11) Å. Each Cu atom is surrounded by four coordinated atoms that are almost coplanar, with dimensions Cu—N = 1.940 (2) and 1.984 (3) Å, and Cu—O = 1.912 (2) and 1.945 (2) Å.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010302064X/de1219sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S010827010302064X/de1219Isup2.hkl
Contains datablock I

CCDC reference: 226116

Comment top

In attempts to develop polynuclear compounds of transition metals using multidentate N-donor groups as ligands (Shieh et al., 1997; Wang et al., 1998; Chang et al., 1999; Peng et al., 2000), we have noticed the behavior of the polypyridylamine N-oxides, because N-oxides offer functional group manipulation and structural modification possibilities that are not usually accessible by other methods (Cope & Ciganek, 1963). In our research system, 2-(2-pyridylamino)pyridine 1-oxide [O-dpaH; dpa is the di(2-pyridyl)amide anion and H represents the dissociable amine H atom] is the simplest multipyridylamine oxide. The O-dpaH frame is stable in air but, to the best of our knowledge, no transition metal complexes of O-dpaH have been reported. We report here the synthesis and structure of the title dinuclear CuII complex, (I).

As shown in Fig. 1, the complex has crystallographically imposed twofold symmetry and the O-dpaH ligand is both bidentate and bridging, linking two Cu atoms with a separation of 3.4270 (11) Å. The O-dpaH ligand takes the syn form, with each Cu atom coordinated to four atoms, viz. an amide N atom, an N-oxide O atom of one O-dpa anion, with a bite angle O1—Cu1—N2 of 83.09 (10)°, a pyridine N atom of another O-dpa anion, and an O atom of a trifluoroacetate group. The Cu1 atom is 0.1648 (10) Å from the best plane of the CuN2O2 moiety. Although this compound can be considered as basically four-coordinate, atoms N2a and O3 (see Fig. 1) occupy possible fifth and sixth coordination sites, with Cu1···N2a = 2.904 (3) Å (N2 is at the equivalent position −x, y, 1/2 − z) and Cu1···O3 = 3.103 (3) Å. This type of coordination is perhaps best described as intermediate between square-planar four-coordination and distorted octahedral geometry. The eight-membered Cu1—N3A—C6A—N2A—Cu1A—N3—C6—N2 chelate ring (Fig. 1) adopts a boat conformation. The individual pyridyl rings are essentially planar [the maximum deviation from the plane is 0.008 (2) Å for atom C5]. In the O-dpa ligand the pyridyl ring planes form a dihedral angle of 55.11 (12)°. There is no H atom on amide atom N2; the original amide H atom is eliminated rather than being transferred to the N atom of a pyridine ring. The N2—C6 bond length [1.404 (4) Å] is almost equal to that in the free ligand [1.395 (2) Å], while the N2—C(5) bond length is apparently shortened from 1.367 (2) Å in the free ligand to 1.347 (4) Å in the complex (Thellend et al., 1997; Bergstad & Backvall, 1998; Jiao & Yu, 2001). The suggested mechanism is illustrated in the reastion scheme above (Wu et al., 1990). The dehydrogenation in (I) only occurs as a consequence of the oxidation of CuI to CuII in the presence of air and traces of water.

Experimental top

A batch of O-dpaH (0.1 g, 0.535 mmol) was dissolved in acetonitrile (20 ml), and copper(I) trifluoroacetate (CuCF3COO; 0.1 g, 0.568 mmol) was added. The resulting solution was stirred for 10 h in air at room temperature. The mixture was filtered and the filtrate was crystallized by diffusion of ether at room temperature. After several days, green single crystals of (I) were obtained. IR (cm−1): 3441.92, 3092.32, 1695.85, 1508.49, 1477.03, 1384.88, 1189.8, 1139.58, 753.28.

Refinement top

In the refinement, H atoms were allowed for as riding atoms, with C—H distances of 0.93 and 0.96 Å.

Computing details top

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek 2003); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. The complex molecule of (I). The `a' suffixes in the atom labels refer to atoms at equivalent position (-x, y, 1/2 − z). Displacement ellipsoids are drawn at the 30% probability level and, for clarity, the acetonitrile molecule of solvation and the H atoms have been omitted.
Bis(µ-di-2-pyridylamine 1-oxide)bis[(trifluoroacetato)copper(II)] acetonitrile disolvate top
Crystal data top
[Cu2(C2F3O2)2(C10H8N3O)2]·C2H3NF(000) = 1624
Mr = 807.62Dx = 1.619 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 2991 reflections
a = 21.203 (4) Åθ = 2.0–25.0°
b = 7.468 (2) ŵ = 1.37 mm1
c = 22.123 (5) ÅT = 293 K
β = 108.947 (15)°Prism, green
V = 3313.2 (13) Å30.38 × 0.25 × 0.22 mm
Z = 4
Data collection top
Enraf-Nonius TurboCAD-4
diffractometer
2106 reflections with I > 2σ(I)
Radiation source: Enraf Nonius FR590Rint = 0.031
Graphite monochromatorθmax = 25.0°, θmin = 2.0°
non–profiled ω/2θ scansh = 250
Absorption correction: ψ scan
(North et al., 1968)
k = 80
Tmin = 0.675, Tmax = 0.738l = 2426
2991 measured reflections3 standard reflections every 60 min
2905 independent reflections intensity decay: 4%
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.033Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.095H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0434P)2 + 4.4467P]
where P = (Fo2 + 2Fc2)/3
2905 reflections(Δ/σ)max < 0.001
226 parametersΔρmax = 0.38 e Å3
0 restraintsΔρmin = 0.31 e Å3
Crystal data top
[Cu2(C2F3O2)2(C10H8N3O)2]·C2H3NV = 3313.2 (13) Å3
Mr = 807.62Z = 4
Monoclinic, C2/cMo Kα radiation
a = 21.203 (4) ŵ = 1.37 mm1
b = 7.468 (2) ÅT = 293 K
c = 22.123 (5) Å0.38 × 0.25 × 0.22 mm
β = 108.947 (15)°
Data collection top
Enraf-Nonius TurboCAD-4
diffractometer
2106 reflections with I > 2σ(I)
Absorption correction: ψ scan
(North et al., 1968)
Rint = 0.031
Tmin = 0.675, Tmax = 0.7383 standard reflections every 60 min
2991 measured reflections intensity decay: 4%
2905 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0330 restraints
wR(F2) = 0.095H-atom parameters constrained
S = 1.02Δρmax = 0.38 e Å3
2905 reflectionsΔρmin = 0.31 e Å3
226 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cu10.077921 (19)0.82944 (5)0.242472 (18)0.03412 (14)
F10.05215 (19)0.8688 (7)0.03118 (14)0.1504 (18)
F20.15263 (18)0.8393 (6)0.04244 (14)0.1319 (15)
F30.0981 (2)0.6210 (5)0.05413 (15)0.1387 (16)
O10.13687 (12)0.6448 (3)0.28787 (11)0.0464 (6)
O20.08703 (13)0.7495 (3)0.16202 (11)0.0503 (6)
O30.16304 (15)0.9529 (4)0.15950 (15)0.0755 (9)
N10.14496 (13)0.6511 (4)0.35119 (13)0.0395 (6)
N20.06414 (12)0.8649 (3)0.32414 (11)0.0340 (6)
N30.02915 (12)1.0443 (3)0.30153 (12)0.0340 (6)
C10.18989 (18)0.5407 (5)0.39069 (18)0.0512 (9)
H10.21420.46190.37430.061*
C20.19980 (19)0.5444 (6)0.45463 (19)0.0591 (10)
H20.23110.46910.48220.071*
C30.1629 (2)0.6614 (5)0.47816 (18)0.0548 (10)
H30.16910.66430.52170.066*
C40.11725 (18)0.7727 (5)0.43759 (16)0.0453 (8)
H40.09230.85020.45380.054*
C50.10760 (15)0.7712 (4)0.37165 (15)0.0359 (7)
C60.03541 (15)1.0238 (4)0.33689 (14)0.0339 (7)
C70.06964 (17)1.1575 (4)0.37807 (16)0.0431 (8)
H70.11381.14080.40320.052*
C80.03727 (19)1.3151 (5)0.38110 (19)0.0507 (9)
H80.05901.40490.40930.061*
C90.02822 (19)1.3394 (5)0.34179 (19)0.0529 (9)
H90.05031.44710.34180.063*
C100.05926 (18)1.2014 (4)0.30325 (18)0.0463 (9)
H100.10311.21680.27700.056*
C110.12250 (18)0.8387 (5)0.13665 (16)0.0443 (8)
C120.1063 (2)0.7924 (7)0.0655 (2)0.0651 (12)
N210.2152 (3)1.0812 (8)0.3520 (4)0.151 (3)
C210.2817 (2)0.8861 (7)0.3010 (2)0.0771 (14)
H21A0.25220.83860.26170.116*
H21B0.30180.78940.32930.116*
H21C0.31580.95600.29240.116*
C220.2448 (2)0.9968 (7)0.3302 (3)0.0775 (14)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0416 (2)0.0280 (2)0.0355 (2)0.00198 (18)0.01635 (16)0.00041 (17)
F10.127 (3)0.249 (5)0.0600 (18)0.080 (3)0.0104 (18)0.019 (2)
F20.137 (3)0.207 (4)0.080 (2)0.034 (3)0.075 (2)0.003 (2)
F30.253 (5)0.104 (3)0.081 (2)0.035 (3)0.083 (3)0.042 (2)
O10.0577 (14)0.0426 (14)0.0423 (13)0.0188 (12)0.0209 (11)0.0026 (11)
O20.0802 (18)0.0338 (12)0.0479 (14)0.0057 (13)0.0358 (13)0.0016 (11)
O30.080 (2)0.068 (2)0.088 (2)0.0229 (18)0.0405 (17)0.0217 (18)
N10.0421 (15)0.0333 (15)0.0432 (16)0.0060 (12)0.0142 (12)0.0055 (12)
N20.0389 (14)0.0308 (15)0.0327 (14)0.0052 (11)0.0123 (12)0.0006 (11)
N30.0372 (14)0.0276 (14)0.0386 (14)0.0026 (11)0.0141 (12)0.0028 (11)
C10.047 (2)0.042 (2)0.061 (2)0.0118 (17)0.0136 (18)0.0081 (18)
C20.052 (2)0.054 (2)0.059 (2)0.007 (2)0.0024 (19)0.017 (2)
C30.063 (2)0.054 (2)0.0392 (19)0.009 (2)0.0050 (17)0.0071 (18)
C40.055 (2)0.041 (2)0.0392 (19)0.0032 (17)0.0148 (17)0.0021 (16)
C50.0388 (17)0.0289 (17)0.0414 (18)0.0018 (14)0.0150 (15)0.0018 (14)
C60.0432 (18)0.0302 (16)0.0318 (15)0.0011 (14)0.0171 (14)0.0014 (13)
C70.0452 (19)0.040 (2)0.0436 (19)0.0040 (16)0.0133 (15)0.0070 (16)
C80.062 (2)0.0342 (19)0.059 (2)0.0067 (18)0.0225 (19)0.0137 (17)
C90.062 (2)0.0287 (18)0.075 (3)0.0041 (17)0.032 (2)0.0093 (18)
C100.045 (2)0.037 (2)0.057 (2)0.0064 (16)0.0175 (17)0.0009 (17)
C110.056 (2)0.0371 (19)0.0447 (19)0.0072 (18)0.0231 (17)0.0015 (17)
C120.080 (3)0.072 (3)0.053 (2)0.008 (2)0.035 (2)0.010 (2)
N210.124 (4)0.101 (4)0.275 (8)0.014 (4)0.130 (5)0.056 (5)
C210.059 (3)0.075 (3)0.103 (4)0.006 (2)0.034 (3)0.004 (3)
C220.056 (3)0.059 (3)0.128 (4)0.006 (2)0.043 (3)0.005 (3)
Geometric parameters (Å, º) top
Cu1—O11.912 (2)C2—C31.383 (6)
Cu1—N21.940 (2)C2—H20.93
Cu1—O21.945 (2)C3—C41.367 (5)
Cu1—N3i1.984 (3)C3—H30.93
Cu1—N2i2.904 (3)C4—C51.406 (4)
Cu1—O33.103 (3)C4—H40.93
F1—C121.287 (5)C6—C71.387 (4)
F2—C121.292 (5)C7—C81.375 (5)
F3—C121.305 (6)C7—H70.93
O1—N11.356 (3)C8—C91.390 (5)
O2—C111.265 (4)C8—H80.93
O3—C111.200 (4)C9—C101.363 (5)
N1—C11.345 (4)C9—H90.93
N1—C51.367 (4)C10—H100.93
N2—C51.347 (4)C11—C121.539 (5)
N2—C61.404 (4)N21—C221.105 (6)
N3—C101.343 (4)C21—C221.428 (6)
N3—C61.347 (4)C21—H21A0.96
N3—Cu1i1.984 (3)C21—H21B0.96
C1—C21.361 (5)C21—H21C0.96
C1—H10.93
O1—Cu1—N283.09 (10)N3—C6—C7121.1 (3)
O1—Cu1—O290.97 (10)N3—C6—N2113.9 (3)
N2—Cu1—O2169.65 (11)C7—C6—N2124.9 (3)
O1—Cu1—N3i171.23 (11)C8—C7—C6119.0 (3)
N2—Cu1—N3i97.73 (10)C8—C7—H7120.5
O2—Cu1—N3i89.44 (11)C6—C7—H7120.5
N1—O1—Cu1111.06 (17)C7—C8—C9119.6 (3)
C11—O2—Cu1119.6 (2)C7—C8—H8120.2
C1—N1—O1118.4 (3)C9—C8—H8120.2
C1—N1—C5123.4 (3)C10—C9—C8118.3 (3)
O1—N1—C5118.2 (2)C10—C9—H9120.9
C5—N2—C6120.9 (3)C8—C9—H9120.9
C5—N2—Cu1112.6 (2)N3—C10—C9122.8 (3)
C6—N2—Cu1120.59 (19)N3—C10—H10118.6
C10—N3—C6119.1 (3)C9—C10—H10118.6
C10—N3—Cu1i122.9 (2)O3—C11—O2129.5 (3)
C6—N3—Cu1i117.6 (2)O3—C11—C12118.8 (4)
N1—C1—C2120.0 (3)O2—C11—C12111.6 (3)
N1—C1—H1120.0F1—C12—F2107.1 (4)
C2—C1—H1120.0F1—C12—F3106.5 (5)
C1—C2—C3119.3 (3)F2—C12—F3105.2 (4)
C1—C2—H2120.4F1—C12—C11111.3 (4)
C3—C2—H2120.4F2—C12—C11113.4 (4)
C4—C3—C2120.2 (4)F3—C12—C11112.9 (3)
C4—C3—H3119.9C22—C21—H21A109.5
C2—C3—H3119.9C22—C21—H21B109.5
C3—C4—C5120.7 (3)H21A—C21—H21B109.5
C3—C4—H4119.7C22—C21—H21C109.5
C5—C4—H4119.7H21A—C21—H21C109.5
N2—C5—N1113.9 (3)H21B—C21—H21C109.5
N2—C5—C4129.6 (3)N21—C22—C21178.6 (7)
N1—C5—C4116.3 (3)
N2—Cu1—O1—N18.1 (2)C3—C4—C5—N2177.5 (3)
O2—Cu1—O1—N1179.6 (2)C3—C4—C5—N11.4 (5)
O1—Cu1—O2—C11104.9 (3)C10—N3—C6—C74.4 (4)
N2—Cu1—O2—C11159.7 (5)Cu1i—N3—C6—C7168.3 (2)
N3i—Cu1—O2—C1166.3 (3)C10—N3—C6—N2171.1 (3)
Cu1—O1—N1—C1173.8 (2)Cu1i—N3—C6—N216.2 (3)
Cu1—O1—N1—C55.3 (3)C5—N2—C6—N3141.4 (3)
O1—Cu1—N2—C59.9 (2)Cu1—N2—C6—N367.7 (3)
O2—Cu1—N2—C565.3 (7)C5—N2—C6—C743.3 (4)
N3i—Cu1—N2—C5161.3 (2)Cu1—N2—C6—C7107.6 (3)
O1—Cu1—N2—C6163.1 (2)N3—C6—C7—C81.9 (5)
O2—Cu1—N2—C6141.6 (5)N2—C6—C7—C8173.0 (3)
N3i—Cu1—N2—C68.1 (2)C6—C7—C8—C91.8 (5)
O1—N1—C1—C2179.4 (3)C7—C8—C9—C102.9 (6)
C5—N1—C1—C20.3 (5)C6—N3—C10—C93.3 (5)
N1—C1—C2—C30.5 (6)Cu1i—N3—C10—C9169.0 (3)
C1—C2—C3—C40.4 (6)C8—C9—C10—N30.4 (6)
C2—C3—C4—C50.6 (6)Cu1—O2—C11—O315.3 (5)
C6—N2—C5—N1162.6 (3)Cu1—O2—C11—C12161.9 (2)
Cu1—N2—C5—N19.6 (3)O3—C11—C12—F199.8 (5)
C6—N2—C5—C421.1 (5)O2—C11—C12—F177.7 (5)
Cu1—N2—C5—C4174.2 (3)O3—C11—C12—F221.1 (6)
C1—N1—C5—N2178.0 (3)O2—C11—C12—F2161.4 (4)
O1—N1—C5—N22.9 (4)O3—C11—C12—F3140.6 (4)
C1—N1—C5—C41.3 (5)O2—C11—C12—F341.9 (5)
O1—N1—C5—C4179.6 (3)
Symmetry code: (i) x, y, z+1/2.

Experimental details

Crystal data
Chemical formula[Cu2(C2F3O2)2(C10H8N3O)2]·C2H3N
Mr807.62
Crystal system, space groupMonoclinic, C2/c
Temperature (K)293
a, b, c (Å)21.203 (4), 7.468 (2), 22.123 (5)
β (°) 108.947 (15)
V3)3313.2 (13)
Z4
Radiation typeMo Kα
µ (mm1)1.37
Crystal size (mm)0.38 × 0.25 × 0.22
Data collection
DiffractometerEnraf-Nonius TurboCAD-4
diffractometer
Absorption correctionψ scan
(North et al., 1968)
Tmin, Tmax0.675, 0.738
No. of measured, independent and
observed [I > 2σ(I)] reflections
2991, 2905, 2106
Rint0.031
(sin θ/λ)max1)0.594
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.033, 0.095, 1.02
No. of reflections2905
No. of parameters226
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.38, 0.31

Computer programs: CAD-4 EXPRESS (Enraf-Nonius, 1994), CAD-4 EXPRESS, XCAD4 (Harms & Wocadlo, 1995), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON (Spek 2003), WinGX (Farrugia, 1999).

Selected geometric parameters (Å, º) top
Cu1—O11.912 (2)O1—N11.356 (3)
Cu1—N21.940 (2)N1—C11.345 (4)
Cu1—O21.945 (2)N1—C51.367 (4)
Cu1—N3i1.984 (3)N2—C51.347 (4)
Cu1—N2i2.904 (3)N2—C61.404 (4)
Cu1—O33.103 (3)
O1—Cu1—N283.09 (10)O1—N1—C5118.2 (2)
O1—Cu1—O290.97 (10)C5—N2—C6120.9 (3)
N2—Cu1—N3i97.73 (10)C5—N2—Cu1112.6 (2)
O2—Cu1—N3i89.44 (11)C6—N2—Cu1120.59 (19)
Symmetry code: (i) x, y, z+1/2.
 

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