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In the title salt, catena-poly[[[aqua­copper(II)]-μ-3-(2-pyri­dyl­methyl­eneamino)propanoato-κ4N,N′,O:O′] perchlorate], {[Cu(C9H9N2O2)(H2O)]ClO4}n, the monomeric unit contains a square-based pyramidal CuII centre. The four basal positions are occupied by a tridentate anionic Schiff base ligand which furnishes an NNO-donor set, with the fourth basal position being occupied by an O-donor atom from the carboxyl­ate group of an adjacent Schiff base ligand. The coordination sphere is completed by a water mol­ecule at the apical position. Inter­estingly, each carboxyl­ate group in the ligand forms a syn–anti-configured bridge between two CuII centres, leading to left-handed chiral helicity. The framework also exhibits O—H...O hydrogen bonds involving the water mol­ecules and an O atom of the perchlorate anion.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010902575X/bm3081sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S010827010902575X/bm3081Isup2.hkl
Contains datablock I

CCDC reference: 746038

Comment top

Well defined chiral metal complexes and metal-containing helical species have attracted much interest in coordination chemistry and materials science (Albrecht, 2001; Erxleben, 2001; Ezuhara et al., 1999), due to their importance in biological systems, asymmetric catalysis, enantioselective separation and nonlinear optical material. The design and synthesis of chiral helical structure are challenging because the chirality must be achieved in the extended crystal structure (Coronado et al., 2003; Imai et al., 2004). In most cases, self-assembly of metal ions and multidentate ligands results in the formation of covalently bonded single-, double-, triple- and even quadruple-stranded metal helicates (Lehn, 1995; Piguet et al., 1997; Williams, 1997), in which left-handed and right-handed helical chains alternate in the lattices, resulting in optically inactive racemic crystals. However, metal-containing chiral helical complexes derived from achiral ligands have received less attention (Biradha et al., 1999; Colacio et al., 1992; Studer et al., 1989). Here we report the preparation of a novel, chiral, single-stranded helical CuII coordination polymer, (I), using a tridentate Schiff base carboxylate-containing ligand derived from the condensation of 2-pyridinecarboxaldehyde with β-alanine.

The structure of (I) consists of helical chains of {[Cu(C9H9N2O2)(H2O)]n+ and of ClO4- anions as shown in Fig. 1. The copper(II) complex exhibits a CuN2O3 square-based-pyramidal coordination environment, with the three donor atoms of the ligand and one O atom belonging to the carboxylate group of an adjacent molecule occupying the four basal positions, while an O atom from a water molecule coordinates in the apical position. The Cu atom is displaced by 0.149 (2) Å from the mean basal plane towards the axial donor. Each carboxylate group bridges two CuII ions in a syn-anti fashion: the intrachain Cu···Cu distance is 4.938 (1) Å, and left-handed chiral helices run parallel to the crystallographic a axis (Fig. 2). While the Cu1—O1 distance of 1.959 (4) Å is comparable to the commonly observed bond lengths between bridging carboxylate O and CuII (Colacio et al., 2000; Studer et al., 1989), the Cu1—O1W distance is somewhat longer. The shortest Cu···O distance between CuII ions and ClO4- anions [Cu1···O6 = 3.305 (2) Å] indicates that such contacts are not significant. One water H atom (H1WB) participates in an intrachain O—H···O hydrogen bond with the carboxylate O1 atom [O1W···O1 2.730 (6) Å, H1WB···O1 2.12 Å, and O1W—H1WB···O1 129°], but there are no significant hydrogen-bonding contacts between the helical chains due to the nearest interchain separation of 2.85 Å [H8B—C3i, (i) = -x + 3/2, -y + 1, z + 1/2] being somewhat longer. However, there are O–H···O hydrogen bonds between the water molecules and the O3 atoms of the perchlorate anions (Table 2, Fig. 1).

Treatment of copper(II) perchlorate with an equimolar amount of the same ligand as (I) in methanol/H2O (3:1 v/v), yields blue crystals of poly[[µ -N-(2-pyridylmethylene)-2-carboxyethylamine)-aqua-copper(II)] perchlorate dihydrate], (II), (Colacio et al., 2000), which has a similar structure to (I). Both complexes exhibit approximately square-based-pyramidal CuII ions which are bridged by syn-anti carboxylate groups to form helical chains. In the lattice of (II), however, left-handed and right-handed helical chains alternate, resulting in optically inactive racemic crystals. The structural differences between (I) and (II) suggest that the solvent molecules exert an influence on the spontaneous resolution of left- and right-handed helices; this opens up the possibility of controlling the formation of the chiral helical structures by varying the nature of the solvent used.

Related literature top

For literaure on metal complexes of N-(2-pyridylmethylene)- 2-carboxyethylamine ligands, see: Colacio et al., 2000.

Experimental top

To a solution of β-alanine (0.080 g, 1.0 mmol) in methanol (10 ml) containing KOH (0.050 g, 1.0 mmol) was added 2-pyridinecarboxaldehyde (0.100 g, 1.0 mmol) in methanol (10 ml). The solution was refluxed with stirring for 2 h. To the cold, filtered solution was added a solution of copper(II) perchlorate (0.350 g, 1.0 mmol) in DMF [N,N-dimethylformamide?] (5 ml) and the mixture stirred for 2 h. After filtration, the filtrate was left to stand at room temperature for one month and blue block-like crystals of the title salt appeared in a yield of 0.11 g (22%).

Refinement top

The water H atoms were located in a difference Fourier map and refined with O–H distances restrained to 0.85 (1) Å and Uiso(H) =1.5Ueq(O). Other H atoms were placed at geometrically calculated positions (C—H = 0.93 Å or 0.97 Å) and refined as riding, with Uiso(H) = 1.2Ueq(C).

Computing details top

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: SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg & Berndt, 2005); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A view of the title salt showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 25% probability level, and intramolecular and intermolecular hydrogen bonds are shown as dashed lines. Symmetry code: A, x - 1/2, -y + 3/2, -z + 2.
[Figure 2] Fig. 2. A ball-and-stick diagram of two parallel neighbouring helical strands. Only the —Cu—OCO—Cu— backbone is shown for clarity.
catena-poly[[[aquacopper(II)]-µ-3-(2-pyridylmethyleneamino)propanoato- κ4N,N',O:O'] perchlorate] top
Crystal data top
[Cu(C9H9N2O2)(H2O)]ClO4F(000) = 724
Mr = 358.19Dx = 1.823 Mg m3
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 1230 reflections
a = 7.9552 (13) Åθ = 2.3–22.3°
b = 11.6740 (19) ŵ = 1.91 mm1
c = 14.050 (2) ÅT = 295 K
V = 1304.8 (4) Å3Block, blue
Z = 40.14 × 0.12 × 0.10 mm
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2457 independent reflections
Radiation source: sealed tube2092 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.034
ϕ and ω scansθmax = 26.0°, θmin = 2.3°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 98
Tmin = 0.776, Tmax = 0.832k = 1414
5173 measured reflectionsl = 517
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)] = 0.054H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.129 w = 1/[σ2(Fo2) + (0.0694P)2]
where P = (Fo2 + 2Fc2)/3
S = 1.01(Δ/σ)max < 0.001
2457 reflectionsΔρmax = 0.48 e Å3
182 parametersΔρmin = 0.34 e Å3
0 restraintsAbsolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.02 (3)
Crystal data top
[Cu(C9H9N2O2)(H2O)]ClO4V = 1304.8 (4) Å3
Mr = 358.19Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 7.9552 (13) ŵ = 1.91 mm1
b = 11.6740 (19) ÅT = 295 K
c = 14.050 (2) Å0.14 × 0.12 × 0.10 mm
Data collection top
Bruker SMART APEX CCD area-detector
diffractometer
2457 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
2092 reflections with I > 2σ(I)
Tmin = 0.776, Tmax = 0.832Rint = 0.034
5173 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.054H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.129Δρmax = 0.48 e Å3
S = 1.01Δρmin = 0.34 e Å3
2457 reflectionsAbsolute structure: Flack (1983)
182 parametersAbsolute structure parameter: 0.02 (3)
0 restraints
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cu10.80083 (9)0.64574 (5)0.94224 (5)0.0439 (2)
O11.0294 (5)0.6929 (3)0.9762 (3)0.0483 (14)
O1W0.7201 (6)0.6400 (4)1.1065 (3)0.0657 (16)
O21.2467 (5)0.6917 (3)1.0726 (3)0.0493 (14)
N10.5962 (7)0.5794 (4)0.8811 (3)0.0483 (17)
N20.8664 (6)0.4825 (4)0.9459 (4)0.0507 (16)
C10.6040 (9)0.4641 (6)0.8758 (4)0.0517 (19)
C20.4783 (10)0.4004 (6)0.8334 (4)0.063 (3)
C30.3409 (11)0.4559 (8)0.7964 (5)0.073 (3)
C40.3310 (9)0.5737 (7)0.8026 (4)0.065 (3)
C50.4637 (8)0.6324 (7)0.8454 (4)0.058 (2)
C60.7563 (8)0.4143 (5)0.9142 (4)0.053 (2)
C71.0267 (8)0.4425 (5)0.9810 (5)0.059 (2)
C81.0949 (8)0.5176 (5)1.0593 (5)0.054 (2)
C91.1272 (7)0.6422 (5)1.0337 (4)0.0407 (17)
Cl10.5922 (2)0.34785 (15)1.17237 (12)0.0586 (5)
O30.5761 (11)0.4523 (6)1.2184 (5)0.131 (3)
O40.7570 (9)0.3329 (8)1.1422 (6)0.139 (4)
O50.4878 (11)0.3482 (7)1.0954 (6)0.136 (3)
O60.5478 (11)0.2652 (7)1.2362 (7)0.158 (4)
H1WB0.632200.680301.114300.0990*
H20.486500.321000.830000.0760*
H1WA0.700100.571301.122900.0990*
H30.255300.414500.767300.0870*
H40.238300.612900.778800.0780*
H50.458700.711900.848900.0690*
H60.772500.335400.915500.0640*
H7A1.106600.440700.928900.0710*
H7B1.014100.364901.004700.0710*
H8A1.199600.484501.081600.0650*
H8B1.016300.515601.112100.0650*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0351 (4)0.0385 (3)0.0581 (4)0.0027 (3)0.0004 (4)0.0005 (4)
O10.036 (2)0.044 (2)0.065 (3)0.0028 (19)0.003 (2)0.0063 (19)
O1W0.065 (3)0.055 (2)0.077 (3)0.013 (3)0.020 (2)0.011 (2)
O20.039 (2)0.0418 (19)0.067 (3)0.0003 (18)0.005 (2)0.003 (2)
N10.048 (3)0.053 (3)0.044 (3)0.011 (3)0.007 (3)0.005 (2)
N20.045 (3)0.045 (2)0.062 (3)0.001 (2)0.011 (3)0.011 (3)
C10.056 (4)0.058 (3)0.041 (3)0.016 (3)0.010 (3)0.006 (3)
C20.068 (5)0.067 (4)0.055 (4)0.023 (4)0.008 (4)0.012 (3)
C30.070 (6)0.096 (6)0.052 (4)0.029 (5)0.004 (4)0.013 (4)
C40.043 (4)0.097 (6)0.055 (4)0.015 (4)0.006 (3)0.005 (4)
C50.046 (4)0.074 (4)0.053 (3)0.007 (4)0.007 (3)0.005 (4)
C60.050 (4)0.044 (3)0.065 (4)0.012 (3)0.011 (3)0.007 (3)
C70.047 (4)0.044 (3)0.086 (5)0.001 (3)0.009 (4)0.001 (3)
C80.049 (4)0.045 (3)0.067 (4)0.006 (3)0.001 (4)0.007 (3)
C90.037 (3)0.041 (3)0.044 (3)0.005 (3)0.007 (2)0.005 (3)
Cl10.0587 (10)0.0531 (9)0.0653 (9)0.0075 (9)0.0086 (8)0.0059 (9)
O30.158 (7)0.100 (5)0.135 (5)0.024 (5)0.042 (6)0.046 (5)
O40.084 (5)0.183 (8)0.154 (6)0.047 (5)0.052 (4)0.055 (6)
O50.140 (6)0.138 (6)0.134 (6)0.018 (5)0.054 (5)0.012 (5)
O60.144 (7)0.127 (6)0.204 (8)0.049 (6)0.092 (6)0.100 (6)
Geometric parameters (Å, º) top
Cu1—O11.959 (4)C1—C61.448 (9)
Cu1—O2i1.957 (4)C1—C21.381 (10)
Cu1—O1W2.397 (4)C2—C31.373 (11)
Cu1—N11.997 (5)C3—C41.380 (12)
Cu1—N21.976 (5)C4—C51.395 (10)
Cl1—O41.390 (8)C7—C81.508 (9)
Cl1—O51.369 (9)C8—C91.520 (8)
Cl1—O31.387 (7)C2—H20.9300
Cl1—O61.364 (9)C3—H30.9300
O1—C91.268 (7)C4—H40.9300
O2—C91.240 (7)C5—H50.9300
O1W—H1WB0.8500C6—H60.9300
O1W—H1WA0.8500C7—H7A0.9700
N1—C11.350 (8)C7—H7B0.9700
N1—C51.321 (8)C8—H8B0.9700
N2—C61.265 (8)C8—H8A0.9700
N2—C71.445 (8)
O1—Cu1—O1W91.26 (17)C1—C2—C3119.1 (7)
O1—Cu1—N1166.05 (18)C2—C3—C4119.5 (7)
O1—Cu1—N291.13 (18)C3—C4—C5118.3 (7)
O1—Cu1—O2i87.57 (16)N1—C5—C4122.5 (7)
O1W—Cu1—N1100.66 (17)N2—C6—C1117.3 (6)
O1W—Cu1—N291.1 (2)C9—C8—C7116.4 (5)
O1W—Cu1—O2i94.06 (17)O2—C9—C8118.1 (5)
N1—Cu1—N281.5 (2)O1—C9—C8119.6 (5)
O2i—Cu1—N198.68 (18)O1—C9—O2122.3 (5)
O2i—Cu1—N2174.7 (2)N2—C7—C8112.3 (5)
O3—Cl1—O6107.2 (5)C1—C2—H2121.00
O4—Cl1—O5109.1 (5)C3—C2—H2120.00
O4—Cl1—O6110.8 (5)C4—C3—H3120.00
O5—Cl1—O6111.6 (5)C2—C3—H3120.00
O3—Cl1—O5108.1 (5)C3—C4—H4121.00
O3—Cl1—O4110.1 (5)C5—C4—H4121.00
Cu1—O1—C9126.4 (4)N1—C5—H5119.00
Cu1ii—O2—C9125.0 (4)C4—C5—H5119.00
Cu1—O1W—H1WB109.00C1—C6—H6121.00
Cu1—O1W—H1WA110.00N2—C6—H6121.00
H1WB—O1W—H1WA109.00C7—C8—H8A108.00
C1—N1—C5118.9 (6)C9—C8—H8B108.00
Cu1—N1—C5129.2 (5)C9—C8—H8A108.00
Cu1—N1—C1111.9 (4)C7—C8—H8B108.00
Cu1—N2—C6114.5 (4)H7A—C7—H7B108.00
Cu1—N2—C7123.6 (4)H8A—C8—H8B107.00
C6—N2—C7121.9 (5)N2—C7—H7A109.00
C2—C1—C6123.4 (6)N2—C7—H7B109.00
N1—C1—C6114.7 (6)C8—C7—H7A109.00
N1—C1—C2121.8 (6)C8—C7—H7B109.00
O1W—Cu1—O1—C953.8 (5)Cu1ii—O2—C9—C8175.1 (4)
N2—Cu1—O1—C937.3 (5)Cu1—N1—C1—C2177.9 (5)
O2i—Cu1—O1—C9147.8 (5)Cu1—N1—C1—C60.4 (6)
O1W—Cu1—N1—C188.0 (4)C5—N1—C1—C20.6 (9)
O1W—Cu1—N1—C593.6 (5)C5—N1—C1—C6178.2 (5)
N2—Cu1—N1—C11.5 (4)Cu1—N1—C5—C4178.5 (4)
N2—Cu1—N1—C5176.9 (5)C1—N1—C5—C40.2 (8)
O2i—Cu1—N1—C1176.2 (4)Cu1—N2—C6—C13.1 (7)
O2i—Cu1—N1—C52.2 (5)C7—N2—C6—C1176.6 (6)
O1—Cu1—N2—C6170.6 (5)Cu1—N2—C7—C831.6 (7)
O1—Cu1—N2—C79.0 (5)C6—N2—C7—C8148.8 (6)
O1W—Cu1—N2—C698.1 (5)N1—C1—C2—C30.6 (9)
O1W—Cu1—N2—C782.3 (5)C6—C1—C2—C3178.0 (6)
N1—Cu1—N2—C62.5 (5)N1—C1—C6—N21.8 (8)
N1—Cu1—N2—C7177.1 (5)C2—C1—C6—N2175.7 (6)
O1—Cu1—O2i—C9i127.5 (5)C1—C2—C3—C40.2 (10)
O1W—Cu1—O2i—C9i36.4 (5)C2—C3—C4—C51.0 (10)
N1—Cu1—O2i—C9i65.1 (5)C3—C4—C5—N11.0 (9)
Cu1—O1—C9—O2158.6 (4)C7—C8—C9—O135.6 (8)
Cu1—O1—C9—C819.2 (7)C7—C8—C9—O2146.6 (6)
Cu1ii—O2—C9—O12.7 (8)C9—C8—C7—N260.4 (7)
Symmetry codes: (i) x1/2, y+3/2, z+2; (ii) x+1/2, y+3/2, z+2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1WB···O1i0.852.122.730 (6)129
O1W—H1WA···O30.852.172.928 (9)149
Symmetry code: (i) x1/2, y+3/2, z+2.

Experimental details

Crystal data
Chemical formula[Cu(C9H9N2O2)(H2O)]ClO4
Mr358.19
Crystal system, space groupOrthorhombic, P212121
Temperature (K)295
a, b, c (Å)7.9552 (13), 11.6740 (19), 14.050 (2)
V3)1304.8 (4)
Z4
Radiation typeMo Kα
µ (mm1)1.91
Crystal size (mm)0.14 × 0.12 × 0.10
Data collection
DiffractometerBruker SMART APEX CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.776, 0.832
No. of measured, independent and
observed [I > 2σ(I)] reflections
5173, 2457, 2092
Rint0.034
(sin θ/λ)max1)0.617
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.054, 0.129, 1.01
No. of reflections2457
No. of parameters182
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.48, 0.34
Absolute structureFlack (1983)
Absolute structure parameter0.02 (3)

Computer programs: SMART (Bruker, 2002), SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg & Berndt, 2005), SHELXTL (Sheldrick, 2008).

Selected geometric parameters (Å, º) top
Cu1—O11.959 (4)O1—C91.268 (7)
Cu1—O2i1.957 (4)O2—C91.240 (7)
Cu1—O1W2.397 (4)N2—C61.265 (8)
Cu1—N11.997 (5)N2—C71.445 (8)
Cu1—N21.976 (5)
O1—Cu1—O1W91.26 (17)O1W—Cu1—N291.1 (2)
O1—Cu1—N1166.05 (18)O1W—Cu1—O2i94.06 (17)
O1—Cu1—N291.13 (18)N1—Cu1—N281.5 (2)
O1—Cu1—O2i87.57 (16)O2i—Cu1—N198.68 (18)
O1W—Cu1—N1100.66 (17)O2i—Cu1—N2174.7 (2)
Symmetry code: (i) x1/2, y+3/2, z+2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1W—H1WB···O1i0.852.122.730 (6)129
O1W—H1WA···O30.852.172.928 (9)149
Symmetry code: (i) x1/2, y+3/2, z+2.
 

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