The title complex, [Cu
4(C
11H
10N
3O
4)
2(C
6H
6N
4S
2)
2](C
6H
2N
3O
7)
2, consists of a circular tetracopper(II) cation with an embedded inversion centre and two uncoordinated picrate (2,4,6-trinitrophenolate) anions. The Cu
II cations at the inner sites of
N-(2-aminoethyl)-
N′-(2-carboxylatophenyl)oxamidate(3−) (oxbe) have square-planar environments and those at the outer sites are in square-pyramidal geometries. The separations of pairs of Cu
II cations bridged by
cis-oxamide and carboxylate groups are 5.2217 (5) and 5.2871 (5) Å, respectively. The tetracopper(II) cations and picrate anions are connected by N—H
O hydrogen bonds into a two-dimensional network parallel to the (010) plane, and these two-dimensional networks are assembled by two types of π–π stacking interactions into a three-dimensional supramolecular structure.
Supporting information
CCDC reference: 757227
All reagents were of analytical reagent grade. The Na[Cu(oxbe)] ligand was
prepared according to the method of Tao, Zang, Mei et al. (2003). The
title complex, [Cu4(oxbe)2(dabt)2](pic)2, (II), was obtained as
follows. A methanol solution (5 ml) of Cu(pic)2.6H2O (0.0628 g, 0.1 mmol)
was added dropwise to an aqueous solution (5 ml) of Na[Cu(oxbe)] (0.0335 g,
0.1 mmol) with continuous stirring. The mixture was stirred quickly for 1 h
and then dabt (0.0199 g, 0.1 mmol) in methanol (5 ml) was further added
dropwise. The solution obtained was stirred at 333 K for 6 h. The resulting
solution was then filtered and the filtrate allowed to stand at room
temperature for two weeks to give well shaped green crystals of (II) suitable
for X-ray analysis (yield 69%). Analysis, calculated for
C46H36Cu4N20O22S4: C 34.46, H 2.26, N 17.47%; found: C 34.61, H
2.18, N 17.71%.
H atoms on primary amine N atom were found in a difference Fourier map. All
other H atoms were placed in calculated positions, with N—H = 0.86 Å and
C—H = 0.93 (aromatic) or 0.97 Å (methylene). All H atoms were refined in
riding mode, with Uiso(H) = 1.2Ueq(parent atom).
Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP (Siemens, 1994) and CAMERON (Watkin et al., 1993); software used to prepare material for publication: WinGX (Farrugia, 1999).
[µ
3-
cis-
N-(2-Aminoethyl)-
N'-(2-
carboxylatophenyl)oxamidato(3-)]bis(2,2'-diamino-4,4'-
bithiazole)tetracopper(II) bis(2,4,6-trinitrophenolate)
top
Crystal data top
[Cu4(C11H10N3O4)2(C6H6N4S2)2](C6H2N3O7)2 | Z = 1 |
Mr = 1603.34 | F(000) = 1616 |
Triclinic, P1 | Dx = 1.895 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 10.5528 (2) Å | Cell parameters from 4260 reflections |
b = 10.9391 (2) Å | θ = 2.2–27.3° |
c = 13.1938 (2) Å | µ = 1.74 mm−1 |
α = 102.367 (1)° | T = 296 K |
β = 98.134 (1)° | Block, green |
γ = 105.059 (1)° | 0.15 × 0.13 × 0.11 mm |
V = 1404.91 (4) Å3 | |
Data collection top
Bruker APEX area-detector diffractometer | 6527 independent reflections |
Radiation source: fine-focus sealed tube | 4897 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.021 |
ϕ and ω scans | θmax = 27.7°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | h = −12→13 |
Tmin = 0.780, Tmax = 0.831 | k = −14→13 |
13345 measured reflections | l = −17→17 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.039 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.103 | H-atom parameters constrained |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0478P)2 + 0.7576P] where P = (Fo2 + 2Fc2)/3 |
6527 reflections | (Δ/σ)max = 0.001 |
433 parameters | Δρmax = 0.69 e Å−3 |
0 restraints | Δρmin = −0.50 e Å−3 |
Crystal data top
[Cu4(C11H10N3O4)2(C6H6N4S2)2](C6H2N3O7)2 | γ = 105.059 (1)° |
Mr = 1603.34 | V = 1404.91 (4) Å3 |
Triclinic, P1 | Z = 1 |
a = 10.5528 (2) Å | Mo Kα radiation |
b = 10.9391 (2) Å | µ = 1.74 mm−1 |
c = 13.1938 (2) Å | T = 296 K |
α = 102.367 (1)° | 0.15 × 0.13 × 0.11 mm |
β = 98.134 (1)° | |
Data collection top
Bruker APEX area-detector diffractometer | 6527 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 4897 reflections with I > 2σ(I) |
Tmin = 0.780, Tmax = 0.831 | Rint = 0.021 |
13345 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.039 | 0 restraints |
wR(F2) = 0.103 | H-atom parameters constrained |
S = 1.04 | Δρmax = 0.69 e Å−3 |
6527 reflections | Δρmin = −0.50 e Å−3 |
433 parameters | |
Special details top
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are
estimated using the full covariance matrix. The cell esds are taken into
account individually in the estimation of esds in distances, angles and
torsion angles; correlations between esds in cell parameters are only used
when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell esds is used for estimating esds 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 | x | y | z | Uiso*/Ueq | |
Cu1 | 0.22895 (3) | 0.41106 (4) | 0.46732 (3) | 0.03526 (11) | |
Cu2 | −0.26026 (3) | 0.14071 (3) | 0.26626 (3) | 0.03419 (11) | |
S1 | −0.38321 (9) | −0.14325 (8) | −0.06068 (6) | 0.0467 (2) | |
S2 | −0.66596 (9) | −0.03211 (9) | 0.33423 (7) | 0.0524 (2) | |
O1 | 0.3204 (2) | 0.5277 (2) | 0.59916 (16) | 0.0448 (5) | |
O2 | 0.3329 (2) | 0.6768 (2) | 0.74471 (16) | 0.0429 (5) | |
O3 | −0.16820 (18) | 0.2453 (2) | 0.41578 (15) | 0.0365 (5) | |
O4 | −0.08239 (19) | 0.1913 (2) | 0.23957 (16) | 0.0436 (5) | |
N1 | 0.0520 (2) | 0.3633 (2) | 0.50777 (18) | 0.0309 (5) | |
N2 | 0.1319 (2) | 0.3107 (3) | 0.32969 (19) | 0.0417 (6) | |
N3 | 0.3836 (3) | 0.4377 (3) | 0.3888 (2) | 0.0512 (7) | |
H3A | 0.4063 | 0.5176 | 0.3702 | 0.061* | |
H3B | 0.4597 | 0.4374 | 0.4203 | 0.061* | |
N4 | −0.3270 (2) | 0.0126 (2) | 0.12505 (18) | 0.0345 (5) | |
N5 | −0.4364 (2) | 0.0505 (2) | 0.28938 (18) | 0.0347 (5) | |
N6 | −0.1632 (3) | 0.0623 (3) | 0.0255 (2) | 0.0637 (9) | |
H6A | −0.1139 | 0.1286 | 0.0760 | 0.076* | |
H6B | −0.1374 | 0.0428 | −0.0333 | 0.076* | |
N7 | −0.4540 (3) | 0.1706 (3) | 0.4526 (2) | 0.0573 (8) | |
H7A | −0.3737 | 0.2221 | 0.4633 | 0.069* | |
H7B | −0.5021 | 0.1817 | 0.4992 | 0.069* | |
C1 | 0.2701 (3) | 0.5724 (3) | 0.6772 (2) | 0.0354 (6) | |
C2 | 0.1346 (3) | 0.4971 (3) | 0.6914 (2) | 0.0340 (6) | |
C3 | 0.0312 (3) | 0.4010 (3) | 0.6121 (2) | 0.0315 (6) | |
C4 | −0.0898 (3) | 0.3456 (3) | 0.6401 (2) | 0.0404 (7) | |
H4 | −0.1579 | 0.2808 | 0.5891 | 0.049* | |
C5 | −0.1106 (4) | 0.3848 (3) | 0.7415 (3) | 0.0488 (8) | |
H5 | −0.1930 | 0.3487 | 0.7575 | 0.059* | |
C6 | −0.0090 (4) | 0.4775 (3) | 0.8191 (3) | 0.0515 (9) | |
H6 | −0.0217 | 0.5031 | 0.8878 | 0.062* | |
C7 | 0.1106 (3) | 0.5314 (3) | 0.7936 (2) | 0.0452 (8) | |
H7 | 0.1787 | 0.5934 | 0.8464 | 0.054* | |
C8 | −0.0429 (3) | 0.2918 (3) | 0.4250 (2) | 0.0307 (6) | |
C9 | 0.0062 (3) | 0.2619 (3) | 0.3221 (2) | 0.0346 (6) | |
C10 | 0.2024 (3) | 0.2938 (4) | 0.2424 (3) | 0.0550 (9) | |
H10A | 0.1735 | 0.2028 | 0.2015 | 0.066* | |
H10B | 0.1846 | 0.3474 | 0.1956 | 0.066* | |
C11 | 0.3447 (3) | 0.3347 (4) | 0.2907 (3) | 0.0665 (12) | |
H11A | 0.3686 | 0.2591 | 0.3046 | 0.080* | |
H11B | 0.3958 | 0.3648 | 0.2404 | 0.080* | |
C12 | −0.2785 (3) | −0.0093 (3) | 0.0381 (2) | 0.0396 (7) | |
C13 | −0.4978 (3) | −0.1673 (3) | 0.0187 (2) | 0.0433 (7) | |
H13 | −0.5796 | −0.2331 | −0.0006 | 0.052* | |
C14 | −0.4525 (3) | −0.0777 (3) | 0.1124 (2) | 0.0330 (6) | |
C15 | −0.5151 (3) | −0.0528 (3) | 0.2039 (2) | 0.0349 (6) | |
C16 | −0.6385 (3) | −0.1089 (3) | 0.2153 (3) | 0.0462 (8) | |
H16 | −0.7012 | −0.1801 | 0.1656 | 0.055* | |
C17 | −0.5034 (3) | 0.0742 (3) | 0.3645 (2) | 0.0383 (7) | |
O5 | 0.4570 (3) | 0.2887 (3) | 0.6403 (2) | 0.0698 (8) | |
O6 | 0.6094 (3) | 0.4168 (3) | 0.8458 (3) | 0.1073 (13) | |
O7 | 0.4962 (3) | 0.5427 (3) | 0.9042 (2) | 0.0782 (9) | |
O8 | 0.0844 (3) | 0.2525 (3) | 0.9667 (2) | 0.0783 (9) | |
O9 | −0.0432 (3) | 0.0973 (3) | 0.8332 (2) | 0.0737 (8) | |
O10 | 0.1325 (4) | −0.0136 (3) | 0.5140 (2) | 0.0843 (9) | |
O11 | 0.2391 (4) | 0.1629 (3) | 0.4759 (2) | 0.0838 (10) | |
N8 | 0.5042 (3) | 0.4390 (3) | 0.8536 (3) | 0.0607 (8) | |
N9 | 0.0618 (3) | 0.1872 (3) | 0.8752 (2) | 0.0554 (8) | |
N10 | 0.1995 (4) | 0.1024 (3) | 0.5396 (2) | 0.0585 (8) | |
C18 | 0.3652 (4) | 0.2681 (3) | 0.6916 (3) | 0.0480 (8) | |
C19 | 0.3788 (3) | 0.3362 (3) | 0.8004 (3) | 0.0479 (8) | |
C20 | 0.2815 (3) | 0.3142 (3) | 0.8582 (3) | 0.0462 (8) | |
H20 | 0.2953 | 0.3647 | 0.9275 | 0.055* | |
C21 | 0.1621 (3) | 0.2159 (3) | 0.8123 (3) | 0.0438 (7) | |
C22 | 0.1367 (3) | 0.1444 (3) | 0.7084 (3) | 0.0442 (7) | |
H22 | 0.0561 | 0.0785 | 0.6781 | 0.053* | |
C23 | 0.2344 (4) | 0.1732 (3) | 0.6502 (2) | 0.0456 (8) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cu1 | 0.02283 (18) | 0.0445 (2) | 0.03250 (19) | 0.00595 (14) | 0.00735 (14) | 0.00180 (15) |
Cu2 | 0.02342 (18) | 0.0438 (2) | 0.02905 (19) | 0.00451 (14) | 0.00783 (13) | 0.00173 (15) |
S1 | 0.0491 (5) | 0.0471 (4) | 0.0360 (4) | 0.0111 (4) | 0.0119 (3) | −0.0038 (3) |
S2 | 0.0407 (5) | 0.0534 (5) | 0.0584 (5) | 0.0015 (4) | 0.0287 (4) | 0.0084 (4) |
O1 | 0.0260 (10) | 0.0541 (13) | 0.0408 (12) | 0.0039 (9) | 0.0078 (9) | −0.0063 (10) |
O2 | 0.0362 (11) | 0.0421 (12) | 0.0383 (11) | 0.0051 (9) | 0.0001 (9) | −0.0015 (9) |
O3 | 0.0229 (10) | 0.0512 (12) | 0.0305 (10) | 0.0062 (9) | 0.0069 (8) | 0.0059 (9) |
O4 | 0.0252 (10) | 0.0616 (14) | 0.0316 (11) | 0.0042 (9) | 0.0078 (8) | −0.0037 (10) |
N1 | 0.0254 (11) | 0.0371 (12) | 0.0285 (12) | 0.0078 (10) | 0.0080 (9) | 0.0057 (10) |
N2 | 0.0251 (12) | 0.0612 (16) | 0.0310 (13) | 0.0060 (11) | 0.0105 (10) | 0.0015 (12) |
N3 | 0.0270 (13) | 0.0674 (18) | 0.0454 (16) | 0.0026 (12) | 0.0130 (11) | −0.0035 (14) |
N4 | 0.0300 (12) | 0.0385 (13) | 0.0305 (12) | 0.0067 (10) | 0.0099 (10) | 0.0020 (10) |
N5 | 0.0295 (12) | 0.0407 (13) | 0.0337 (13) | 0.0091 (10) | 0.0109 (10) | 0.0079 (11) |
N6 | 0.0458 (17) | 0.083 (2) | 0.0380 (16) | −0.0101 (15) | 0.0216 (13) | −0.0073 (15) |
N7 | 0.0395 (15) | 0.078 (2) | 0.0417 (16) | 0.0036 (14) | 0.0208 (12) | −0.0022 (14) |
C1 | 0.0288 (14) | 0.0422 (16) | 0.0335 (15) | 0.0117 (12) | 0.0007 (12) | 0.0089 (13) |
C2 | 0.0336 (15) | 0.0371 (15) | 0.0331 (15) | 0.0118 (12) | 0.0077 (12) | 0.0108 (12) |
C3 | 0.0305 (14) | 0.0354 (14) | 0.0297 (14) | 0.0110 (12) | 0.0078 (11) | 0.0087 (12) |
C4 | 0.0371 (16) | 0.0421 (16) | 0.0360 (16) | 0.0020 (13) | 0.0118 (13) | 0.0072 (13) |
C5 | 0.050 (2) | 0.0526 (19) | 0.0434 (18) | 0.0067 (16) | 0.0236 (15) | 0.0130 (15) |
C6 | 0.064 (2) | 0.056 (2) | 0.0331 (17) | 0.0116 (17) | 0.0213 (16) | 0.0083 (15) |
C7 | 0.0485 (19) | 0.0480 (18) | 0.0321 (16) | 0.0088 (15) | 0.0055 (14) | 0.0046 (14) |
C8 | 0.0247 (13) | 0.0367 (15) | 0.0325 (14) | 0.0108 (11) | 0.0089 (11) | 0.0088 (12) |
C9 | 0.0263 (14) | 0.0429 (16) | 0.0308 (14) | 0.0085 (12) | 0.0071 (11) | 0.0038 (12) |
C10 | 0.0306 (16) | 0.081 (3) | 0.0408 (18) | 0.0077 (16) | 0.0154 (14) | −0.0033 (17) |
C11 | 0.0335 (18) | 0.097 (3) | 0.048 (2) | 0.0007 (19) | 0.0191 (15) | −0.010 (2) |
C12 | 0.0390 (17) | 0.0456 (17) | 0.0292 (15) | 0.0094 (14) | 0.0092 (12) | 0.0024 (13) |
C13 | 0.0413 (17) | 0.0368 (16) | 0.0447 (18) | 0.0067 (13) | 0.0112 (14) | 0.0009 (14) |
C14 | 0.0283 (14) | 0.0323 (14) | 0.0378 (15) | 0.0079 (11) | 0.0102 (12) | 0.0075 (12) |
C15 | 0.0330 (15) | 0.0313 (14) | 0.0403 (16) | 0.0068 (12) | 0.0119 (12) | 0.0098 (12) |
C16 | 0.0415 (18) | 0.0398 (17) | 0.0498 (19) | 0.0007 (14) | 0.0176 (15) | 0.0053 (14) |
C17 | 0.0315 (15) | 0.0486 (17) | 0.0388 (16) | 0.0129 (13) | 0.0146 (12) | 0.0140 (14) |
O5 | 0.0757 (19) | 0.0700 (17) | 0.0762 (18) | 0.0212 (14) | 0.0547 (16) | 0.0204 (15) |
O6 | 0.0511 (19) | 0.089 (2) | 0.163 (4) | 0.0109 (17) | 0.036 (2) | −0.002 (2) |
O7 | 0.094 (2) | 0.0533 (16) | 0.080 (2) | 0.0110 (15) | 0.0258 (17) | 0.0089 (15) |
O8 | 0.0647 (18) | 0.116 (2) | 0.0380 (14) | 0.0047 (16) | 0.0253 (13) | 0.0044 (15) |
O9 | 0.0419 (15) | 0.111 (2) | 0.0522 (15) | −0.0015 (15) | 0.0178 (12) | 0.0139 (15) |
O10 | 0.107 (3) | 0.073 (2) | 0.0594 (18) | 0.0158 (18) | 0.0294 (17) | −0.0030 (15) |
O11 | 0.146 (3) | 0.087 (2) | 0.0523 (16) | 0.063 (2) | 0.0524 (19) | 0.0327 (16) |
N8 | 0.058 (2) | 0.0536 (19) | 0.070 (2) | 0.0095 (16) | 0.0299 (17) | 0.0153 (16) |
N9 | 0.0442 (17) | 0.088 (2) | 0.0411 (16) | 0.0198 (16) | 0.0196 (13) | 0.0255 (16) |
N10 | 0.079 (2) | 0.062 (2) | 0.0513 (18) | 0.0397 (18) | 0.0318 (17) | 0.0152 (16) |
C18 | 0.059 (2) | 0.0466 (18) | 0.055 (2) | 0.0263 (17) | 0.0319 (17) | 0.0216 (16) |
C19 | 0.0467 (19) | 0.0477 (18) | 0.057 (2) | 0.0178 (15) | 0.0217 (16) | 0.0186 (16) |
C20 | 0.050 (2) | 0.056 (2) | 0.0396 (17) | 0.0214 (16) | 0.0183 (15) | 0.0141 (15) |
C21 | 0.0417 (18) | 0.061 (2) | 0.0398 (17) | 0.0218 (16) | 0.0201 (14) | 0.0222 (15) |
C22 | 0.0460 (18) | 0.0529 (19) | 0.0416 (17) | 0.0198 (15) | 0.0168 (14) | 0.0176 (15) |
C23 | 0.062 (2) | 0.0520 (19) | 0.0364 (17) | 0.0306 (17) | 0.0228 (15) | 0.0152 (15) |
Geometric parameters (Å, º) top
Cu1—O1 | 1.876 (2) | C2—C3 | 1.414 (4) |
Cu1—N1 | 1.985 (2) | C3—C4 | 1.400 (4) |
Cu1—N2 | 1.894 (2) | C4—C5 | 1.382 (4) |
Cu1—N3 | 2.045 (2) | C4—H4 | 0.9300 |
Cu2—O2i | 2.341 (2) | C5—C6 | 1.381 (5) |
Cu2—O3 | 2.0145 (19) | C5—H5 | 0.9300 |
Cu2—O4 | 1.919 (2) | C6—C7 | 1.368 (5) |
Cu2—N4 | 1.982 (2) | C6—H6 | 0.9300 |
Cu2—N5 | 1.964 (2) | C7—H7 | 0.9300 |
C8—O3 | 1.265 (3) | C10—C11 | 1.456 (5) |
C8—N1 | 1.313 (3) | C10—H10A | 0.9700 |
C8—C9 | 1.522 (4) | C10—H10B | 0.9700 |
C9—O4 | 1.278 (3) | C11—H11A | 0.9700 |
C9—N2 | 1.275 (4) | C11—H11B | 0.9700 |
S1—C13 | 1.715 (3) | C13—C14 | 1.337 (4) |
S1—C12 | 1.732 (3) | C13—H13 | 0.9300 |
S2—C16 | 1.715 (3) | C14—C15 | 1.465 (4) |
S2—C17 | 1.739 (3) | C15—C16 | 1.332 (4) |
O1—C1 | 1.285 (3) | C16—H16 | 0.9300 |
O2—C1 | 1.242 (3) | O5—C18 | 1.259 (4) |
N1—C3 | 1.415 (3) | O6—N8 | 1.210 (4) |
N2—C10 | 1.462 (4) | O7—N8 | 1.217 (4) |
N3—C11 | 1.448 (4) | O8—N9 | 1.218 (4) |
N3—H3A | 0.9381 | O9—N9 | 1.236 (4) |
N3—H3B | 0.8517 | O10—N10 | 1.228 (4) |
N4—C12 | 1.323 (4) | O11—N10 | 1.230 (4) |
N4—C14 | 1.394 (3) | N8—C19 | 1.461 (5) |
N5—C17 | 1.317 (4) | N9—C21 | 1.447 (4) |
N5—C15 | 1.393 (4) | N10—C23 | 1.443 (4) |
N6—C12 | 1.319 (4) | C18—C19 | 1.437 (5) |
N6—H6A | 0.8600 | C18—C23 | 1.442 (5) |
N6—H6B | 0.8600 | C19—C20 | 1.367 (4) |
N7—C17 | 1.324 (4) | C20—C21 | 1.383 (5) |
N7—H7A | 0.8600 | C20—H20 | 0.9300 |
N7—H7B | 0.8600 | C21—C22 | 1.376 (4) |
C1—C2 | 1.513 (4) | C22—C23 | 1.382 (4) |
C2—C7 | 1.397 (4) | C22—H22 | 0.9300 |
| | | |
O1—Cu1—N1 | 95.46 (9) | C6—C7—H7 | 118.7 |
N1—Cu1—N2 | 84.42 (10) | C2—C7—H7 | 118.7 |
N2—Cu1—N3 | 81.51 (10) | O3—C8—N1 | 131.1 (3) |
O3—Cu2—O4 | 83.44 (8) | O3—C8—C9 | 114.5 (2) |
N4—Cu2—N5 | 82.54 (9) | N1—C8—C9 | 114.4 (2) |
O2i—Cu2—O4 | 102.56 (9) | N2—C9—O4 | 128.2 (3) |
O2i—Cu2—N5 | 89.85 (9) | N2—C9—C8 | 115.2 (2) |
O2i—Cu2—N4 | 107.11 (9) | O4—C9—C8 | 116.6 (2) |
O2i—Cu2—O3 | 85.08 (8) | C11—C10—N2 | 106.4 (3) |
C1—O1—Cu1 | 127.92 (18) | C11—C10—H10A | 110.5 |
C1—O2—Cu2i | 116.40 (19) | N2—C10—H10A | 110.5 |
O1—Cu1—N2 | 173.15 (11) | C11—C10—H10B | 110.5 |
O1—Cu1—N3 | 98.33 (9) | N2—C10—H10B | 110.5 |
N1—Cu1—N3 | 165.85 (10) | H10A—C10—H10B | 108.6 |
O4—Cu2—N5 | 167.33 (10) | N3—C11—C10 | 114.3 (3) |
O4—Cu2—N4 | 91.25 (9) | N3—C11—H11A | 108.7 |
N5—Cu2—O3 | 100.37 (9) | C10—C11—H11A | 108.7 |
N4—Cu2—O3 | 167.55 (9) | N3—C11—H11B | 108.7 |
C13—S1—C12 | 90.33 (14) | C10—C11—H11B | 108.7 |
C16—S2—C17 | 89.88 (15) | H11A—C11—H11B | 107.6 |
C8—O3—Cu2 | 111.99 (17) | N6—C12—N4 | 124.6 (3) |
C9—O4—Cu2 | 113.42 (17) | N6—C12—S1 | 122.4 (2) |
C8—N1—C3 | 124.6 (2) | N4—C12—S1 | 113.0 (2) |
C8—N1—Cu1 | 111.00 (18) | C14—C13—S1 | 110.2 (2) |
C3—N1—Cu1 | 124.39 (18) | C14—C13—H13 | 124.9 |
C9—N2—C10 | 125.2 (3) | S1—C13—H13 | 124.9 |
C9—N2—Cu1 | 114.98 (19) | C13—C14—N4 | 115.7 (3) |
C10—N2—Cu1 | 119.81 (19) | C13—C14—C15 | 131.0 (3) |
C11—N3—Cu1 | 108.12 (19) | N4—C14—C15 | 113.2 (2) |
C11—N3—H3A | 106.7 | C16—C15—N5 | 115.2 (3) |
Cu1—N3—H3A | 115.1 | C16—C15—C14 | 129.7 (3) |
C11—N3—H3B | 106.8 | N5—C15—C14 | 114.9 (2) |
Cu1—N3—H3B | 117.9 | C15—C16—S2 | 110.7 (2) |
H3A—N3—H3B | 101.5 | C15—C16—H16 | 124.6 |
C12—N4—C14 | 110.8 (2) | S2—C16—H16 | 124.6 |
C12—N4—Cu2 | 134.5 (2) | N5—C17—N7 | 123.8 (3) |
C14—N4—Cu2 | 114.69 (18) | N5—C17—S2 | 112.8 (2) |
C17—N5—C15 | 111.4 (2) | N7—C17—S2 | 123.4 (2) |
C17—N5—Cu2 | 133.8 (2) | O6—N8—O7 | 123.7 (4) |
C15—N5—Cu2 | 114.45 (18) | O6—N8—C19 | 118.9 (3) |
C12—N6—H6A | 120.0 | O7—N8—C19 | 117.4 (3) |
C12—N6—H6B | 120.0 | O8—N9—O9 | 123.1 (3) |
H6A—N6—H6B | 120.0 | O8—N9—C21 | 118.7 (3) |
C17—N7—H7A | 120.0 | O9—N9—C21 | 118.2 (3) |
C17—N7—H7B | 120.0 | O10—N10—O11 | 123.7 (3) |
H7A—N7—H7B | 120.0 | O10—N10—C23 | 118.9 (3) |
O2—C1—O1 | 121.0 (3) | O11—N10—C23 | 117.4 (3) |
O2—C1—C2 | 118.0 (3) | O5—C18—C19 | 123.7 (3) |
O1—C1—C2 | 121.0 (2) | O5—C18—C23 | 125.0 (3) |
C7—C2—C3 | 118.2 (3) | C19—C18—C23 | 111.3 (3) |
C7—C2—C1 | 115.0 (3) | C20—C19—C18 | 124.8 (3) |
C3—C2—C1 | 126.8 (3) | C20—C19—N8 | 116.8 (3) |
C4—C3—C2 | 118.3 (3) | C18—C19—N8 | 118.4 (3) |
C4—C3—N1 | 121.9 (2) | C19—C20—C21 | 119.0 (3) |
C2—C3—N1 | 119.8 (2) | C19—C20—H20 | 120.5 |
C5—C4—C3 | 121.6 (3) | C21—C20—H20 | 120.5 |
C5—C4—H4 | 119.2 | C22—C21—C20 | 121.5 (3) |
C3—C4—H4 | 119.2 | C22—C21—N9 | 119.3 (3) |
C6—C5—C4 | 119.9 (3) | C20—C21—N9 | 119.2 (3) |
C6—C5—H5 | 120.0 | C21—C22—C23 | 118.1 (3) |
C4—C5—H5 | 120.0 | C21—C22—H22 | 120.9 |
C7—C6—C5 | 119.2 (3) | C23—C22—H22 | 120.9 |
C7—C6—H6 | 120.4 | C22—C23—C18 | 125.0 (3) |
C5—C6—H6 | 120.4 | C22—C23—N10 | 116.1 (3) |
C6—C7—C2 | 122.7 (3) | C18—C23—N10 | 118.8 (3) |
| | | |
Cu1—O1—C1—O2 | −157.0 (2) | C4—C5—C6—C7 | 1.3 (5) |
Cu2i—O2—C1—O1 | 104.8 (3) | C5—C6—C7—C2 | 0.4 (5) |
O1—C1—C2—C3 | −22.1 (5) | C3—C2—C7—C6 | −1.1 (5) |
O1—C1—C2—C7 | 160.2 (3) | C1—C2—C7—C6 | 176.8 (3) |
O2—C1—C2—C3 | 159.8 (3) | Cu2—O3—C8—N1 | −179.3 (3) |
O2—C1—C2—C7 | −17.9 (4) | Cu2—O3—C8—C9 | 1.9 (3) |
O6—N8—C19—C18 | −47.5 (5) | C3—N1—C8—O3 | 2.7 (5) |
O6—N8—C19—C20 | 133.9 (4) | Cu1—N1—C8—O3 | −177.5 (3) |
O7—N8—C19—C18 | 133.0 (4) | C3—N1—C8—C9 | −178.5 (2) |
O7—N8—C19—C20 | −45.6 (5) | Cu1—N1—C8—C9 | 1.3 (3) |
O8—N9—C21—C20 | 1.5 (5) | C10—N2—C9—O4 | −0.7 (6) |
O8—N9—C21—C22 | −178.8 (3) | Cu1—N2—C9—O4 | 179.6 (3) |
O9—N9—C21—C20 | −178.7 (3) | C10—N2—C9—C8 | 179.0 (3) |
O9—N9—C21—C22 | 1.0 (5) | Cu1—N2—C9—C8 | −0.6 (4) |
O10—N10—C23—C18 | 142.4 (4) | Cu2—O4—C9—N2 | −179.7 (3) |
O10—N10—C23—C22 | −38.3 (5) | Cu2—O4—C9—C8 | 0.5 (3) |
O11—N10—C23—C18 | −37.8 (5) | O3—C8—C9—N2 | 178.4 (3) |
O11—N10—C23—C22 | 141.6 (3) | N1—C8—C9—N2 | −0.6 (4) |
N1—Cu1—O1—C1 | −10.6 (3) | O3—C8—C9—O4 | −1.7 (4) |
N3—Cu1—O1—C1 | 166.2 (3) | N1—C8—C9—O4 | 179.3 (3) |
O4—Cu2—O3—C8 | −1.4 (2) | C9—N2—C10—C11 | −165.2 (3) |
N5—Cu2—O3—C8 | 166.41 (19) | Cu1—N2—C10—C11 | 14.4 (4) |
N4—Cu2—O3—C8 | 63.9 (5) | Cu1—N3—C11—C10 | 34.3 (4) |
O2i—Cu2—O3—C8 | −104.6 (2) | N2—C10—C11—N3 | −31.6 (5) |
N5—Cu2—O4—C9 | −108.0 (4) | C14—N4—C12—N6 | 178.2 (3) |
N4—Cu2—O4—C9 | −168.3 (2) | Cu2—N4—C12—N6 | −3.0 (5) |
O3—Cu2—O4—C9 | 0.4 (2) | C14—N4—C12—S1 | −1.4 (3) |
O2i—Cu2—O4—C9 | 83.8 (2) | Cu2—N4—C12—S1 | 177.46 (17) |
O1—Cu1—N1—C8 | 171.8 (2) | C13—S1—C12—N6 | −178.3 (3) |
N2—Cu1—N1—C8 | −1.3 (2) | C13—S1—C12—N4 | 1.2 (3) |
N3—Cu1—N1—C8 | 4.8 (6) | C12—S1—C13—C14 | −0.7 (3) |
O1—Cu1—N1—C3 | −8.4 (2) | S1—C13—C14—N4 | 0.1 (4) |
N2—Cu1—N1—C3 | 178.5 (2) | S1—C13—C14—C15 | 176.5 (3) |
N3—Cu1—N1—C3 | −175.4 (4) | C12—N4—C14—C13 | 0.8 (4) |
N1—Cu1—N2—C9 | 1.0 (2) | Cu2—N4—C14—C13 | −178.2 (2) |
N3—Cu1—N2—C9 | −177.5 (3) | C12—N4—C14—C15 | −176.2 (3) |
N1—Cu1—N2—C10 | −178.6 (3) | Cu2—N4—C14—C15 | 4.7 (3) |
N3—Cu1—N2—C10 | 2.9 (3) | C17—N5—C15—C16 | −1.8 (4) |
O1—Cu1—N3—C11 | 167.3 (3) | Cu2—N5—C15—C16 | −175.4 (2) |
N2—Cu1—N3—C11 | −19.7 (3) | C17—N5—C15—C14 | 174.5 (3) |
N1—Cu1—N3—C11 | −25.8 (6) | Cu2—N5—C15—C14 | 0.9 (3) |
O4—Cu2—N4—C12 | −13.3 (3) | C13—C14—C15—C16 | −4.6 (6) |
N5—Cu2—N4—C12 | 177.8 (3) | N4—C14—C15—C16 | 171.9 (3) |
O3—Cu2—N4—C12 | −77.7 (5) | C13—C14—C15—N5 | 179.9 (3) |
O2i—Cu2—N4—C12 | 90.3 (3) | N4—C14—C15—N5 | −3.6 (4) |
O4—Cu2—N4—C14 | 165.5 (2) | N5—C15—C16—S2 | 1.6 (4) |
N5—Cu2—N4—C14 | −3.4 (2) | C14—C15—C16—S2 | −174.0 (3) |
O3—Cu2—N4—C14 | 101.1 (4) | C17—S2—C16—C15 | −0.7 (3) |
O2i—Cu2—N4—C14 | −90.9 (2) | C15—N5—C17—N7 | −177.2 (3) |
O4—Cu2—N5—C17 | 128.4 (4) | Cu2—N5—C17—N7 | −5.3 (5) |
N4—Cu2—N5—C17 | −170.4 (3) | C15—N5—C17—S2 | 1.1 (3) |
O3—Cu2—N5—C17 | 21.8 (3) | Cu2—N5—C17—S2 | 173.04 (16) |
O2i—Cu2—N5—C17 | −63.1 (3) | C16—S2—C17—N5 | −0.2 (3) |
O4—Cu2—N5—C15 | −59.9 (5) | C16—S2—C17—N7 | 178.1 (3) |
N4—Cu2—N5—C15 | 1.3 (2) | O5—C18—C19—C20 | −178.9 (3) |
O3—Cu2—N5—C15 | −166.4 (2) | C23—C18—C19—C20 | 0.4 (5) |
O2i—Cu2—N5—C15 | 108.6 (2) | O5—C18—C19—N8 | 2.5 (5) |
Cu2i—O2—C1—C2 | −77.1 (3) | C23—C18—C19—N8 | −178.1 (3) |
Cu1—O1—C1—C2 | 25.0 (4) | C18—C19—C20—C21 | 3.0 (5) |
C7—C2—C3—C4 | 0.2 (4) | N8—C19—C20—C21 | −178.5 (3) |
C1—C2—C3—C4 | −177.5 (3) | C19—C20—C21—C22 | −3.3 (5) |
C7—C2—C3—N1 | −179.8 (3) | C19—C20—C21—N9 | 176.5 (3) |
C1—C2—C3—N1 | 2.6 (4) | C20—C21—C22—C23 | 0.1 (5) |
C8—N1—C3—C4 | 11.6 (4) | N9—C21—C22—C23 | −179.6 (3) |
Cu1—N1—C3—C4 | −168.2 (2) | C21—C22—C23—C18 | 3.7 (5) |
C8—N1—C3—C2 | −168.5 (3) | C21—C22—C23—N10 | −175.6 (3) |
Cu1—N1—C3—C2 | 11.8 (4) | O5—C18—C23—C22 | 175.5 (3) |
C2—C3—C4—C5 | 1.5 (5) | C19—C18—C23—C22 | −3.8 (5) |
N1—C3—C4—C5 | −178.6 (3) | O5—C18—C23—N10 | −5.2 (5) |
C3—C4—C5—C6 | −2.2 (5) | C19—C18—C23—N10 | 175.5 (3) |
Symmetry code: (i) −x, −y+1, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3B···O1ii | 0.85 | 2.31 | 3.025 (3) | 141 |
N3—H3A···O5ii | 0.94 | 2.28 | 3.161 (4) | 157 |
N6—H6A···O4 | 0.86 | 2.07 | 2.772 (3) | 138 |
N6—H6B···O9iii | 0.86 | 2.25 | 3.043 (4) | 152 |
N7—H7A···O3 | 0.86 | 2.31 | 3.050 (3) | 145 |
N7—H7B···O5iv | 0.86 | 2.14 | 2.932 (3) | 153 |
Symmetry codes: (ii) −x+1, −y+1, −z+1; (iii) x, y, z−1; (iv) x−1, y, z. |
Experimental details
Crystal data |
Chemical formula | [Cu4(C11H10N3O4)2(C6H6N4S2)2](C6H2N3O7)2 |
Mr | 1603.34 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 296 |
a, b, c (Å) | 10.5528 (2), 10.9391 (2), 13.1938 (2) |
α, β, γ (°) | 102.367 (1), 98.134 (1), 105.059 (1) |
V (Å3) | 1404.91 (4) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 1.74 |
Crystal size (mm) | 0.15 × 0.13 × 0.11 |
|
Data collection |
Diffractometer | Bruker APEX area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) |
Tmin, Tmax | 0.780, 0.831 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 13345, 6527, 4897 |
Rint | 0.021 |
(sin θ/λ)max (Å−1) | 0.654 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.039, 0.103, 1.04 |
No. of reflections | 6527 |
No. of parameters | 433 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.69, −0.50 |
Selected geometric parameters (Å, º) topCu1—O1 | 1.876 (2) | Cu2—O3 | 2.0145 (19) |
Cu1—N1 | 1.985 (2) | Cu2—O4 | 1.919 (2) |
Cu1—N2 | 1.894 (2) | Cu2—N4 | 1.982 (2) |
Cu1—N3 | 2.045 (2) | Cu2—N5 | 1.964 (2) |
Cu2—O2i | 2.341 (2) | | |
| | | |
O1—Cu1—N1 | 95.46 (9) | O2i—Cu2—O3 | 85.08 (8) |
N1—Cu1—N2 | 84.42 (10) | O1—Cu1—N2 | 173.15 (11) |
N2—Cu1—N3 | 81.51 (10) | O1—Cu1—N3 | 98.33 (9) |
O3—Cu2—O4 | 83.44 (8) | N1—Cu1—N3 | 165.85 (10) |
N4—Cu2—N5 | 82.54 (9) | O4—Cu2—N5 | 167.33 (10) |
O2i—Cu2—O4 | 102.56 (9) | O4—Cu2—N4 | 91.25 (9) |
O2i—Cu2—N5 | 89.85 (9) | N5—Cu2—O3 | 100.37 (9) |
O2i—Cu2—N4 | 107.11 (9) | N4—Cu2—O3 | 167.55 (9) |
Symmetry code: (i) −x, −y+1, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3B···O1ii | 0.85 | 2.31 | 3.025 (3) | 141.3 |
N3—H3A···O5ii | 0.94 | 2.28 | 3.161 (4) | 156.8 |
N6—H6A···O4 | 0.86 | 2.07 | 2.772 (3) | 138.4 |
N6—H6B···O9iii | 0.86 | 2.25 | 3.043 (4) | 152.3 |
N7—H7A···O3 | 0.86 | 2.31 | 3.050 (3) | 144.7 |
N7—H7B···O5iv | 0.86 | 2.14 | 2.932 (3) | 153.2 |
Symmetry codes: (ii) −x+1, −y+1, −z+1; (iii) x, y, z−1; (iv) x−1, y, z. |
The geometric parameters of the π–π stacking interactions in (II) topFirst ring | Second ring | Cg—Cg | α | β | Separation |
R1 | R1v | 3.4785 (17) | 0 | 13.78 | C13v[3.375 (4)], C14v[3.378 (3)] |
R1 | R2vi | 3.7852 (18) | 5.70 (16) | 21.55 | C20vi[3.436 (4)], C21vi[3.529 (4)] |
Notes:
R1 denotes the thiazole ring consisting of atoms N4/C12/S1/C13/C14. R2 is
the C18–C23 benzene ring.
Cg—Cg, α and β denote the centroid-to-centroid separation, the
dihedral angle between the ring planes and the offset angle, respectively.
The separation is the perpendicular distance of the specified atom of the
second ring from the plane of the first ring.
Symmetry codes: (v) -x - 1, -y, -z; (vi) -x, -y, 1 - z. |
Many studies have been devoted to the crystal engineering of metal coordination complexes with supramolecular architectures formed through relatively weak interactions such as hydrogen bonds and π–π stacking interactions (Blake et al., 1999; Lin et al., 2003). N,N'-Bis(substituted)oxamides, which can afford symmetric and asymmetric oxamidate bridges by the cis–trans conformational change (Ojima & Nonoyama, 1988; Ruiz et al., 1999), have a typical ability to form three-dimensional supramolecular architectures (Zhang et al., 2001; Delgado et al., 2006; Sun et al., 2007, 2008). Compared with studies dealing with symmetric N,N'-bis(substituted)oxamide polynuclear systems (Nakatani et al., 1991; Lloret et al., 1992; Santana et al., 2004; Tang et al., 2005), relatively few studies of asymmetric N,N'-bis(substituted)oxamide polynuclear complexes have been reported to date, owing to difficulties in their synthesis (Matović et al., 2005; Zang et al., 2003). However, polynuclear complexes bridged by asymmetric N,N'-bis(substituted)oxamide ligands containing aromatic groups are characterized by connecting into a three-dimensional supramolecular structure via hydrogen bonds and π–π stacking, while they have shown outstanding properties [What sorts of properties?] (Yu et al., 1989, 1991; Larionova et al., 1997; Zang et al., 2003; Tao, Zang, Cheng et al., 2003; Tao, Zang, Hu et al., 2003; Tao, Zang, Mei et al., 2003; Tao et al., 2004; Matović et al., 2005; Zhu et al., 2007), which prompted us to design and synthesize this type of polynuclear complex to explore their particular structures and functionalities.
Recently, we first reported the crystal structure of a cyclic tetracopper(II) complex bridged by the N-benzoato-N'-(2-amino-2-methylethyl)oxamide (H3oxbm) ligand and end-capped with 2,2'-bipyridine (bpy), namely, [Cu2(oxbm)(bpy)Cl]2.2H2O, (I). That study revealed that the terminal ligands (bpy) and counterions (Cl-) played a dominant role in the construction of the three-dimensional supramolecular structure (Gu et al., 2009). In order to understand better the influence of terminal ligands and counterions on the crystal structure of these compounds, it was found necessary to synthesize a series of tetranuclear compexes of essentially analogous skeletal structure except for the terminal ligands and counterions. As an extension of our work, in this paper the title novel tetranuclear copper(II) complex, [Cu2(oxbe)(dabt)]2.(pic)2, (II), has been synthesized using sodium N-benzoato-N'-(2-aminoethyl)oxamidocopper(II), {Na[Cu(oxbe)]} as a bridging ligand, and 2,2'-diamino-4,4'-bithiazole (dabt) and picrate anions (pic-) as terminal ligands and counterions, respectively, and its crystal structure is reported here.
A perspective view of (II) is depicted in Fig. 1, and selected bond distances and angles are listed in Table 1. The molecular structure of (II) consists of a circular tetranuclear copper(II) cation, [Cu2(oxbe)(dabt)]22+, located on an inversion centre and two uncoordinated symmetrically related pic- anions. The tetracopper(II) cation can be considered as a pair of cis-oxamidate-bridged dinuclear copper(II) complexes assembled through carboxyl bridges to form an end-to-end circular system. The separations of the CuII cations through the oxamide and carboxyl bridges are 5.2217 (5) and 5.2871 (5) Å, respectively. The oxamide group chelates to atoms Cu1 and Cu2 with the usual bite angles of 84.42 (10) and 83.44 (8)°, respectively. The carboxyl group bridges the CuII cations in a skew–skew fashion, with torsion angles of Cu1—O1—C1—O2 = -157.0 (2)° and Cu2i—O2—C1—O1 = 104.8 (3)° [symmetry code: (i) -x, 1 - y, 1 - z], which are similar to those found in other related complexes (Duan et al., 2006; Tong et al., 1997; Gu et al., 2009).
In complex (II), the two CuII cations are in different coordination environments, which are distinct from those in complex (I). Atom Cu1, at the inner site of oxbe3- ligand, has a distorted square-planar geometry formed by atoms N1, N2, N3 and O1, of which the maximum displacement from the coordination plane is 0.0401 (15) Å for atom N2. Atom Cu1 is displaced only 0.0770 (14) Å from the plane towards atom O11, with a Cu1···O11 distance of 2.770 (3) Å. Such a distance is too long to be considered a coordination bond. Furthermore, the bond valences (Shields et al., 2000) around atom Cu1 are 0.550, 0.468, 0.598 and 0.467 for atoms O1, N1, N2 and N3, respectively, with a sum of 2.083. In comparison, atom O11 only contributes 0.049 to the bond valence, less than 3% of the total Cu1 valence, and can thus be reasonably ignored. In complex (I), instead, atom Cu1 has a square-pyramidal geometry and the corresponding displacement from the basal plane is 0.2403 (13) Å, with an axial Cu—Cl bond of 2.6832 (16) Å. The bond valence of the apical Cl atom is 0.158. In complex (II), the environment around atom Cu2 can be best described as a distorted square-pyramidal geometry, similar to that in complex (I), with τ values of 0.12 (Addison et al., 1984). Atom Cu2 is coordinated by the exo O atoms (O3 and O4) of the oxamide group and atoms N4 and N5 of the dabt molecule, which define the basal plane with deviations in the range 0.0037 (11)–0.0041 (12) Å. Atom Cu2 is displaced 0.2004 (12) Å out of the basal plane towards apical carboxyl atom O2i, with a Cu2—O2i bond length of 2.341 (2) Å [symmetry code: (i) ? Please complete].
The oxbe3- ligand coordinates atoms Cu1 with a six-membered and two five-membered chelate rings. The Cu1/N2/C10/C11/N3 five-membered ring has a twist conformation, with puckering parameters (Cremer & Pople, 1975) of Q = 0.302 (4) Å and ϕ = 122.0 (6)°, and the remaining Cu1/N1/C8/C9/N2 five-membered ring is almost planar, as expected. The puckering parameters of the Cu1/O1/C1–C3/N1 six-membered ring are Q = 0.205 (3) Å, θ = 78.1 (8)° and ϕ = 112.4 (7)°. The Cu1—N3 bond [2.045 (2) Å] is longer than the Cu1—N1 [1.985 (2) Å] and Cu1—N2 bonds [1.894 (2) Å], which is consistent with the stronger donor abilities of the deprotonated amide N atoms compared with the primary amine N atoms (Jubert et al., 2002).
Comparison of complex (II) with the previously reported complex (I) shows that they share the same metal ion and an analogous oxamidate-bridged skeletal structure. The main differences between them are the terminal ligands and the counterions [dabt and pic- in (II) and bpy and Cl- in (I)]. The substitution of Cl- by pic- contributes not only to changing the coordination geometries of the CuII cations (due to the larger space occupied by pic-) but also affects the intermolecular interactions. The picrate anions and dabt terminal ligands are better hydrogen-bond acceptors and donors than chloride anions and bpy ligands, which results in a stronger two-dimensional network formed by N—H···O hydrogen bonds, parallel to the (010) plane (Fig. 2 and Table 2). Furthermore, there are two kinds of offset π–π stacking interactions in complex (II) (Table 3 and Fig. 3). One is observed between the two thiazole rings containing atoms S1 and S1v [symmetry code: (v) -1 - x, -y, -z], with a closest separation of 3.375 (4) Å (C13v). The other is between the S1 thiazole ring and the picratevi benzene ring [symmetry code: (vi) -x, -y, 1 - z]; the closest distance between atom C20vi and the thiazole plane is 3.436 (4) Å. These stackings form stronger interlayer interactions than those in complex (I), where only one kind of π–π stacking occurs with a nearest separation of 3.421 (4) Å. These stacking interactions assemble the hydrogen-bonded layers into a three-dimensional supramolecular structure.
It is clear from the above discussion that terminal ligands and counterions play an important role in the construction of the three-dimensional supramolecular structures of these compounds, and further investigations involving different sets are in progress in our laboratory.