Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270112028442/bg3151sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270112028442/bg3151Isup2.hkl |
CCDC reference: 899053
The title compound, (I), was synthesized by solution reaction of Cu2(OH)2CO3 (23 mg, 0.1 mmol), H2IDA (27 mg, 0.2 mmol) and HTMA (29 mg, 0.2 mmol) in water (15 ml) at room temperature. The subsequent solution was filtered and left to evaporate. After several days, blue crystals of (I) were obtained in a yield of 93% (65.6 mg). Suitable samples for single-crystal X-ray diffraction were selected directly from the obtained crop.
All H atoms bounded to C and N atoms were added at calculated positions, with C—H = 0.99 Å and C—N = 0.93 Å, and refined using a riding model, with Uiso = 1.2Ueq(C,N). Water H atoms were located from difference Fourier peaks and refined isotropically, with a restrained O—H distance of 0.82 (2) Å.
Data collection: PROCESS-AUTO (Rigaku, 1998); cell refinement: PROCESS-AUTO (Rigaku, 1998); data reduction: CrystalStructure (Rigaku/MSC, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
[Cu(C4H5NO4)(C6H12N4)(H2O)] | F(000) = 732 |
Mr = 352.84 | Dx = 1.821 Mg m−3 |
Orthorhombic, Pca21 | Mo Kα radiation, λ = 0.71075 Å |
Hall symbol: P 2c -2ac | Cell parameters from 3918 reflections |
a = 9.800 (2) Å | θ = 2.1–27.5° |
b = 19.039 (4) Å | µ = 1.73 mm−1 |
c = 6.8975 (15) Å | T = 130 K |
V = 1286.9 (5) Å3 | Plate, blue |
Z = 4 | 0.32 × 0.16 × 0.07 mm |
Rigaku R-AXIS RAPID diffractometer | 2760 independent reflections |
Radiation source: fine-focus sealed tube | 2546 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.032 |
Detector resolution: 14.6306 pixels mm-1 | θmax = 27.5°, θmin = 2.3° |
CCD profile fitting scans | h = −12→12 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −24→24 |
Tmin = 0.607, Tmax = 0.889 | l = −8→7 |
9636 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.026 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.061 | w = 1/[σ2(Fo2) + (0.0332P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max = 0.001 |
2760 reflections | Δρmax = 0.27 e Å−3 |
198 parameters | Δρmin = −0.31 e Å−3 |
3 restraints | Absolute structure: Flack (1983), with 1156 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.004 (15) |
[Cu(C4H5NO4)(C6H12N4)(H2O)] | V = 1286.9 (5) Å3 |
Mr = 352.84 | Z = 4 |
Orthorhombic, Pca21 | Mo Kα radiation |
a = 9.800 (2) Å | µ = 1.73 mm−1 |
b = 19.039 (4) Å | T = 130 K |
c = 6.8975 (15) Å | 0.32 × 0.16 × 0.07 mm |
Rigaku R-AXIS RAPID diffractometer | 2760 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 2546 reflections with I > 2σ(I) |
Tmin = 0.607, Tmax = 0.889 | Rint = 0.032 |
9636 measured reflections |
R[F2 > 2σ(F2)] = 0.026 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.061 | Δρmax = 0.27 e Å−3 |
S = 1.01 | Δρmin = −0.31 e Å−3 |
2760 reflections | Absolute structure: Flack (1983), with 1156 Friedel pairs |
198 parameters | Absolute structure parameter: 0.004 (15) |
3 restraints |
Experimental. Analysis, calculated for C10H19CuN5O5 (%): C 34.04, H 5.43, N 19.85, O 22.67; found: C 34.87, H 5.01, N 19.12, O 23.11. IR (KBr, ν, cm-1): 3234 s, 2958 m, 2543 w, 1616 s, 1384 s, 1256 s, 1227 s, 1062 s, 997 s, 911 s, 824 ms, 786 ms, 664 ms, 585 m, 502 m. |
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. |
x | y | z | Uiso*/Ueq | ||
Cu1 | 0.00027 (2) | 0.197212 (12) | 0.39193 (10) | 0.00979 (8) | |
N1 | −0.02127 (17) | 0.09581 (10) | 0.4529 (3) | 0.0112 (4) | |
H1 | 0.0133 | 0.0879 | 0.5765 | 0.013* | |
N2 | 0.00598 (16) | 0.29694 (10) | 0.2881 (3) | 0.0085 (4) | |
N3 | −0.1040 (2) | 0.37629 (10) | 0.0535 (3) | 0.0158 (4) | |
N4 | −0.02168 (18) | 0.42196 (10) | 0.3641 (4) | 0.0140 (5) | |
N5 | 0.1408 (2) | 0.38550 (10) | 0.1147 (3) | 0.0140 (4) | |
C1 | 0.1937 (2) | 0.10073 (12) | 0.2734 (4) | 0.0137 (5) | |
C2 | 0.0652 (2) | 0.05800 (11) | 0.3128 (4) | 0.0128 (5) | |
H2A | 0.0144 | 0.0507 | 0.1904 | 0.015* | |
H2B | 0.0903 | 0.0114 | 0.3657 | 0.015* | |
C3 | −0.1665 (2) | 0.07701 (11) | 0.4530 (4) | 0.0121 (5) | |
H3A | −0.1888 | 0.0524 | 0.5754 | 0.014* | |
H3B | −0.1849 | 0.0443 | 0.3444 | 0.014* | |
C4 | −0.2576 (2) | 0.14163 (11) | 0.4328 (3) | 0.0119 (5) | |
C5 | −0.1031 (2) | 0.30530 (11) | 0.1353 (4) | 0.0148 (5) | |
H5A | −0.0872 | 0.2709 | 0.0301 | 0.018* | |
H5B | −0.1934 | 0.2952 | 0.1933 | 0.018* | |
C6 | −0.0202 (2) | 0.35078 (13) | 0.4425 (4) | 0.0137 (5) | |
H6A | −0.1091 | 0.3409 | 0.5049 | 0.016* | |
H6B | 0.0516 | 0.3473 | 0.5430 | 0.016* | |
C7 | 0.1404 (2) | 0.31484 (11) | 0.1963 (4) | 0.0127 (5) | |
H7A | 0.2135 | 0.3111 | 0.2949 | 0.015* | |
H7B | 0.1603 | 0.2805 | 0.0923 | 0.015* | |
C8 | 0.1109 (2) | 0.43607 (12) | 0.2700 (4) | 0.0156 (5) | |
H8A | 0.1101 | 0.4841 | 0.2151 | 0.019* | |
H8B | 0.1842 | 0.4339 | 0.3686 | 0.019* | |
C9 | −0.1278 (2) | 0.42641 (12) | 0.2116 (4) | 0.0161 (5) | |
H9A | −0.2182 | 0.4170 | 0.2701 | 0.019* | |
H9B | −0.1292 | 0.4746 | 0.1580 | 0.019* | |
C10 | 0.0303 (2) | 0.39039 (13) | −0.0297 (4) | 0.0170 (5) | |
H10A | 0.0305 | 0.4381 | −0.0871 | 0.020* | |
H10B | 0.0481 | 0.3564 | −0.1353 | 0.020* | |
O1 | 0.18308 (15) | 0.16815 (8) | 0.2986 (3) | 0.0134 (3) | |
O2 | 0.29669 (15) | 0.07122 (8) | 0.2125 (3) | 0.0181 (4) | |
O3 | −0.38293 (15) | 0.13328 (8) | 0.4293 (3) | 0.0202 (4) | |
O4 | −0.19778 (15) | 0.20125 (7) | 0.4182 (3) | 0.0143 (4) | |
O5 | 0.05476 (18) | 0.22227 (9) | 0.7116 (3) | 0.0147 (3) | |
H52 | 0.126 (2) | 0.2055 (14) | 0.727 (5) | 0.031 (10)* | |
H51 | −0.001 (2) | 0.2024 (14) | 0.778 (5) | 0.021 (10)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cu1 | 0.00771 (12) | 0.00726 (12) | 0.01439 (14) | 0.00032 (9) | 0.00182 (11) | 0.00077 (16) |
N1 | 0.0117 (9) | 0.0115 (10) | 0.0104 (11) | −0.0005 (7) | −0.0004 (7) | −0.0005 (8) |
N2 | 0.0083 (9) | 0.0083 (10) | 0.0090 (11) | 0.0004 (6) | 0.0010 (8) | −0.0010 (8) |
N3 | 0.0171 (10) | 0.0134 (10) | 0.0170 (11) | −0.0001 (8) | −0.0040 (9) | 0.0023 (9) |
N4 | 0.0176 (10) | 0.0102 (9) | 0.0141 (15) | −0.0013 (7) | 0.0033 (10) | −0.0035 (9) |
N5 | 0.0132 (10) | 0.0131 (10) | 0.0156 (11) | 0.0014 (8) | 0.0031 (9) | 0.0032 (9) |
C1 | 0.0133 (11) | 0.0158 (11) | 0.0119 (12) | 0.0010 (9) | 0.0028 (10) | 0.0030 (10) |
C2 | 0.0111 (11) | 0.0097 (10) | 0.0175 (12) | 0.0004 (8) | 0.0040 (10) | −0.0028 (9) |
C3 | 0.0091 (10) | 0.0118 (11) | 0.0153 (13) | −0.0008 (8) | 0.0025 (9) | 0.0013 (9) |
C4 | 0.0103 (9) | 0.0138 (10) | 0.0115 (13) | 0.0015 (8) | 0.0009 (10) | 0.0015 (9) |
C5 | 0.0153 (12) | 0.0110 (11) | 0.0183 (14) | −0.0004 (9) | −0.0089 (11) | 0.0021 (10) |
C6 | 0.0179 (11) | 0.0130 (11) | 0.0103 (14) | 0.0001 (8) | 0.0028 (9) | −0.0010 (9) |
C7 | 0.0107 (11) | 0.0132 (11) | 0.0144 (13) | 0.0010 (8) | 0.0033 (10) | 0.0019 (10) |
C8 | 0.0137 (11) | 0.0106 (11) | 0.0223 (15) | −0.0028 (9) | −0.0015 (11) | 0.0025 (10) |
C9 | 0.0153 (11) | 0.0108 (11) | 0.0222 (14) | 0.0038 (9) | 0.0021 (11) | 0.0063 (11) |
C10 | 0.0211 (12) | 0.0176 (13) | 0.0123 (12) | 0.0031 (10) | 0.0004 (10) | 0.0062 (10) |
O1 | 0.0113 (8) | 0.0102 (8) | 0.0188 (9) | 0.0011 (6) | 0.0016 (7) | 0.0021 (7) |
O2 | 0.0123 (8) | 0.0151 (8) | 0.0269 (10) | 0.0035 (6) | 0.0067 (8) | 0.0023 (8) |
O3 | 0.0093 (7) | 0.0177 (8) | 0.0336 (12) | −0.0006 (6) | −0.0010 (8) | 0.0045 (8) |
O4 | 0.0092 (7) | 0.0120 (7) | 0.0218 (10) | 0.0009 (5) | 0.0039 (8) | 0.0012 (7) |
O5 | 0.0110 (8) | 0.0157 (8) | 0.0174 (9) | 0.0015 (7) | 0.0007 (8) | 0.0018 (8) |
Cu1—O4 | 1.9508 (15) | C1—C2 | 1.523 (3) |
Cu1—O1 | 1.9824 (16) | C2—H2A | 0.9900 |
Cu1—N1 | 1.987 (2) | C2—H2B | 0.9900 |
Cu1—N2 | 2.030 (2) | C3—C4 | 1.527 (3) |
Cu1—O5 | 2.318 (2) | C3—H3A | 0.9900 |
N1—C2 | 1.473 (3) | C3—H3B | 0.9900 |
N1—C3 | 1.467 (3) | C4—O3 | 1.238 (3) |
N1—H1 | 0.9300 | C4—O4 | 1.282 (2) |
N2—C7 | 1.501 (3) | C5—H5A | 0.9900 |
N2—C6 | 1.500 (3) | C5—H5B | 0.9900 |
N2—C5 | 1.510 (3) | C6—H6A | 0.9900 |
N3—C10 | 1.461 (3) | C6—H6B | 0.9900 |
N3—C5 | 1.464 (3) | C7—H7A | 0.9900 |
N3—C9 | 1.468 (3) | C7—H7B | 0.9900 |
N4—C6 | 1.459 (3) | C8—H8A | 0.9900 |
N4—C8 | 1.477 (3) | C8—H8B | 0.9900 |
N4—C9 | 1.482 (3) | C9—H9A | 0.9900 |
N5—C7 | 1.458 (3) | C9—H9B | 0.9900 |
N5—C8 | 1.470 (3) | C10—H10A | 0.9900 |
N5—C10 | 1.474 (3) | C10—H10B | 0.9900 |
C1—O2 | 1.229 (3) | O5—H52 | 0.773 (17) |
C1—O1 | 1.299 (3) | O5—H51 | 0.805 (17) |
O4—Cu1—O1 | 160.08 (8) | H3A—C3—H3B | 107.9 |
O4—Cu1—N1 | 85.01 (7) | O3—C4—O4 | 124.47 (19) |
O1—Cu1—N1 | 83.89 (7) | O3—C4—C3 | 118.60 (19) |
O4—Cu1—N2 | 91.33 (6) | O4—C4—C3 | 116.93 (18) |
O1—Cu1—N2 | 96.98 (7) | N3—C5—N2 | 111.75 (19) |
N1—Cu1—N2 | 170.50 (9) | N3—C5—H5A | 109.3 |
O4—Cu1—O5 | 97.63 (8) | N2—C5—H5A | 109.3 |
O1—Cu1—O5 | 99.11 (7) | N3—C5—H5B | 109.3 |
N1—Cu1—O5 | 91.33 (8) | N2—C5—H5B | 109.3 |
N2—Cu1—O5 | 97.86 (8) | H5A—C5—H5B | 107.9 |
C2—N1—C3 | 116.04 (19) | N4—C6—N2 | 111.9 (2) |
C2—N1—Cu1 | 105.96 (14) | N4—C6—H6A | 109.2 |
C3—N1—Cu1 | 109.89 (14) | N2—C6—H6A | 109.2 |
C2—N1—H1 | 108.2 | N4—C6—H6B | 109.2 |
C3—N1—H1 | 108.2 | N2—C6—H6B | 109.2 |
Cu1—N1—H1 | 108.2 | H6A—C6—H6B | 107.9 |
C7—N2—C6 | 107.13 (17) | N5—C7—N2 | 112.00 (18) |
C7—N2—C5 | 107.6 (2) | N5—C7—H7A | 109.2 |
C6—N2—C5 | 107.60 (17) | N2—C7—H7A | 109.2 |
C7—N2—Cu1 | 112.67 (13) | N5—C7—H7B | 109.2 |
C6—N2—Cu1 | 112.59 (16) | N2—C7—H7B | 109.2 |
C5—N2—Cu1 | 109.00 (13) | H7A—C7—H7B | 107.9 |
C10—N3—C5 | 108.40 (19) | N5—C8—N4 | 112.11 (19) |
C10—N3—C9 | 108.41 (19) | N5—C8—H8A | 109.2 |
C5—N3—C9 | 108.3 (2) | N4—C8—H8A | 109.2 |
C6—N4—C8 | 108.84 (17) | N5—C8—H8B | 109.2 |
C6—N4—C9 | 108.84 (17) | N4—C8—H8B | 109.2 |
C8—N4—C9 | 107.1 (2) | H8A—C8—H8B | 107.9 |
C7—N5—C8 | 108.81 (19) | N3—C9—N4 | 112.26 (19) |
C7—N5—C10 | 108.51 (19) | N3—C9—H9A | 109.2 |
C8—N5—C10 | 107.76 (19) | N4—C9—H9A | 109.2 |
O2—C1—O1 | 124.2 (2) | N3—C9—H9B | 109.2 |
O2—C1—C2 | 119.7 (2) | N4—C9—H9B | 109.2 |
O1—C1—C2 | 115.96 (18) | H9A—C9—H9B | 107.9 |
N1—C2—C1 | 109.35 (18) | N3—C10—N5 | 112.6 (2) |
N1—C2—H2A | 109.8 | N3—C10—H10A | 109.1 |
C1—C2—H2A | 109.8 | N5—C10—H10A | 109.1 |
N1—C2—H2B | 109.8 | N3—C10—H10B | 109.1 |
C1—C2—H2B | 109.8 | N5—C10—H10B | 109.1 |
H2A—C2—H2B | 108.3 | H10A—C10—H10B | 107.8 |
N1—C3—C4 | 111.77 (18) | C1—O1—Cu1 | 113.03 (13) |
N1—C3—H3A | 109.3 | C4—O4—Cu1 | 115.32 (13) |
C4—C3—H3A | 109.3 | Cu1—O5—H52 | 105 (3) |
N1—C3—H3B | 109.3 | Cu1—O5—H51 | 107 (2) |
C4—C3—H3B | 109.3 | H52—O5—H51 | 109 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H51···O3i | 0.81 (2) | 2.03 (2) | 2.821 (3) | 167 (3) |
O5—H52···O1ii | 0.77 (2) | 2.06 (2) | 2.832 (2) | 173 (3) |
N1—H1···O2ii | 0.93 | 2.11 | 2.876 (3) | 139 |
C3—H3B···O2iii | 0.99 | 2.39 | 3.293 (3) | 152 |
C8—H8B···N5ii | 0.99 | 2.58 | 3.536 (3) | 162 |
Symmetry codes: (i) −x−1/2, y, z+1/2; (ii) −x+1/2, y, z+1/2; (iii) x−1/2, −y, z. |
Experimental details
Crystal data | |
Chemical formula | [Cu(C4H5NO4)(C6H12N4)(H2O)] |
Mr | 352.84 |
Crystal system, space group | Orthorhombic, Pca21 |
Temperature (K) | 130 |
a, b, c (Å) | 9.800 (2), 19.039 (4), 6.8975 (15) |
V (Å3) | 1286.9 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.73 |
Crystal size (mm) | 0.32 × 0.16 × 0.07 |
Data collection | |
Diffractometer | Rigaku R-AXIS RAPID diffractometer |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.607, 0.889 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9636, 2760, 2546 |
Rint | 0.032 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.026, 0.061, 1.01 |
No. of reflections | 2760 |
No. of parameters | 198 |
No. of restraints | 3 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.27, −0.31 |
Absolute structure | Flack (1983), with 1156 Friedel pairs |
Absolute structure parameter | 0.004 (15) |
Computer programs: PROCESS-AUTO (Rigaku, 1998), CrystalStructure (Rigaku/MSC, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
Cu1—O4 | 1.9508 (15) | Cu1—N2 | 2.030 (2) |
Cu1—O1 | 1.9824 (16) | Cu1—O5 | 2.318 (2) |
Cu1—N1 | 1.987 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
O5—H51···O3i | 0.805 (17) | 2.030 (18) | 2.821 (3) | 167 (3) |
O5—H52···O1ii | 0.773 (17) | 2.063 (18) | 2.832 (2) | 173 (3) |
N1—H1···O2ii | 0.93 | 2.11 | 2.876 (3) | 138.9 |
C3—H3B···O2iii | 0.99 | 2.39 | 3.293 (3) | 151.7 |
C8—H8B···N5ii | 0.99 | 2.58 | 3.536 (3) | 161.5 |
Symmetry codes: (i) −x−1/2, y, z+1/2; (ii) −x+1/2, y, z+1/2; (iii) x−1/2, −y, z. |
Second-order nonlinear optical (NLO) compounds are usually materials with advanced functionality, which must crystallize in a noncentrosymmetric space group (Chai et al., 2010a; Bella, 2001; Kanis et al., 1994). Due to the rapid development of laser techniques in recent decades, these materials have attracted more and more attention for their applications in second-harmonic generation (SHG), wave-mixing effects, optical parametric oscillator (OPO) processes and so on. There are currently two types of inorganic second-order NLO crystal materials which have been developed into commercial products (Shen, 2002; Boyd, 2008). The first corresponds to oxide-type crystals, for instance potassium dihydrogen phosphate (KDP), ammonium dihydrogen phosphate (ADP), barium metaborate (β-BBO), lithium triborate (LBO) etc. These types of crystal are suitable for working in the visible and near-IR regions. The second type of inorganic second-order NLO materials corresponds to semiconductor crystals, for example tellurium, reddish silver (Ag3AsS3) etc. This type of material is suitable for working in the far-IR region.
However, these inorganic second-order NLO crystals can still not meet the various needs of optical signal processing. Thus, new second-order NLO materials of coordinated compounds have attracted widespread attention and made great developments in the last 20 years (Nalwa & Miyata, 1997). For this type of second-order NLO material, intramolecular charge transfer, i.e. metal-to-ligand charge transfer (MLCT), ligand-to-metal charge transfer (LMCT) or intra-ligand charge transfer (ILCT), are key factors (Frazier et al., 1986; Qin et al., 1994), while the noncentrosymmetric character of the space group in which the coordinated compound crystallizes is an inescapable prerequisite for the possible existence of its second-order NLO properties. The controlled synthesis of noncentrosymmetric crystals is still a significant challenge, although many noncentrosymmetric coordinated compounds of this sort have been obtained so far (Bella, 2001; Kanis et al., 1994). According to reports in the available literature, the cage-like hexamethylenetetramine ligand (HMTA) may easily form noncentrosymmetric coordinated crystal structures with metal cations (Chen et al., 2005; Banerjee et al., 2010; Guo et al., 2010; Sun et al., 2011). In addition, the iminodiacetate anion (IDA-) is a good tridentate chelating ligand for coordinating to copper(II) in order to form a [Cu(IDA)(H2O)2]n polymeric structure (Roman-Alpiste et al., 1999), which would allow interruption by N-heterocyclic donors (the auxiliary ligand) to form an asymmetric mononuclear molecule. In this work, we utilized HMTA and IDA- to assemble with a copper(II) salt, and successfully obtained the title mixed-ligand coordinated compound, (I), which crystallizes in the noncentrosymmetric space group Pca21.
Compound (I) consists of a mononuclear neutral molecule (Fig. 1), made up of one HMTA and one IDA- ligand, one coordinated water molecule, and one CuII cation, which exhibits a distorted square-pyramidal coordination geometry constructed from two O atoms and one N atom from the IDA ligand, one N atom from the HTMA ligand and another O atom from the water molecule. Within this CuO3N2 square pyramid, the bond lengths (Table 1) are similar to those in analogous structures (Roman-Alpiste et al., 1999; Kundu et al., 2005; Chen et al., 1990; Zhang et al., 2008; Yang et al., 2011). The IDA ligand adopts a three-coordinated terminal binding mode, and the fact that it does not exhibit a bridging mode, as in some previously reported polymeric structures containing the ligand (Roman-Alpiste et al., 1999; Podder et al., 1979), could be attributed to the steric blocking effect of the large HTMA terminal ligand.
The mononuclear molecules of (I) are connected to each other to form a two-dimensional supramolecular layered structure, mainly by virtue of two pairs of O—H···O hydrogen bonds and one N—H···O hydrogen bond (Table 2). As shown in Fig. 2, adjacent molecules are connected (entries 1–3 in Table 2) to form supramolecular layers. From a topological point of view, the molecular centres can be regarded as supramolecular 4-connected nodes and the hydrogen-bonding interactions as linkages, thus defining a (4,4) supramocular network structure. These layers stack with their c-glide related neighbours in an alternating ···ABABA··· fashion along the b axis (Fig 3).
The UV–VIS diffuse-reflectance spectrum of (I) was measured on a powder sample previously examined by powder X-ray diffraction, and is plotted in Fig. 4 as F(R)2 versus wavelength, according to the Kubelka–Munk function (Chai et al., 2007a,b). As can be seen, there are two obvious absorption bands in the spectrum. One strong band, located in the region of about 200–350 nm, is due to the transition of ligands between different energy levels. The other, very weak, band at about 550–800 nm is due either to a d–d transition of the copper(II) centre or to an LMCT mechanism. That is to say, (I) absorbs very few photons in the visible region, so this region is a suitable window for SHG. Thus, (I) may be investigated as a potential second-order NLO material.