A second polymorph of aqua­(2,9-di­methyl-1,10-phenanthroline-κ2 N,N′)bis­(formato-κO)copper(II)

Jian-Li Lin; Wei Xu; Hong-Zhen Xie

doi:10.1107/S1600536808022812

. 2008 Jul 26;64(Pt 8):m1062. doi: 10.1107/S1600536808022812

A second polymorph of aqua(2,9-dimethyl-1,10-phenanthroline-κ² N,N′)bis(formato-κO)copper(II)

Jian-Li Lin ^a,^*, Wei Xu ^a, Hong-Zhen Xie ^a

PMCID: PMC2961975 PMID: 21203045

Abstract

A new monoclinic polymorphic form of the title compound, [Cu(HCO₂)₂(C₁₄H₁₂N₂)(H₂O)], is described. It differs from the first orthorhombic polymorph [Pan, Lin & Zheng (2005 ▶). Z. Kristallogr. New Cryst. Struct. 220, 495–496] in the deviation of the Cu atom relative to the plane of the 2,9-dimethyl-1,10-phenanthroline (dmp) ligand. In the present structure, the Cu atom is shifted from the mean plane of the dmp ligand by only 0.005 (1) Å, compared with 0.318 (6) Å in the orthorhombic form. Hydrogen-bonding and π–π stacking interactions (mean interplanar distance of 3.59 Å in the title compound) in the two different polymorphs are both essential to the supramolecular assembly.

Related literature

For the orthorhombic polymorph, see: Pan et al. (2005 ▶).

Experimental

Crystal data

[Cu(HCO₂)₂(C₁₄H₁₂N₂)(H₂O)]
M _r = 379.85
Monoclinic,
a = 10.669 (2) Å
b = 7.7677 (16) Å
c = 19.338 (4) Å
β = 94.22 (3)°
V = 1598.3 (6) Å³
Z = 4
Mo Kα radiation
μ = 1.40 mm⁻¹
T = 295 (2) K
0.26 × 0.17 × 0.09 mm

Data collection

Bruker P4 diffractometer
Absorption correction: multi-scan (XSCANS; Siemens, 1996 ▶) T _min = 0.749, T _max = 0.879
15099 measured reflections
3632 independent reflections
3202 reflections with I > 2σ(I)
R _int = 0.019
3 standard reflections every 97 reflections intensity decay: none

Refinement

R[F ² > 2σ(F ²)] = 0.026
wR(F ²) = 0.072
S = 1.06
3632 reflections
219 parameters
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.22 e Å⁻³

Data collection: XSCANS (Siemens, 1996 ▶); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXL97; software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808022812/fj2128sup1.cif

e-64-m1062-sup1.cif^{(18.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808022812/fj2128Isup2.hkl

e-64-m1062-Isup2.hkl^{(178.1KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected geometric parameters (Å, °).

Cu—O1	1.9450 (12)
Cu—O3	1.9546 (12)
Cu—O5	1.9726 (12)
Cu—N1	2.0328 (13)
Cu—N2	2.2801 (15)

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O1—Cu—O3	95.53 (6)
O1—Cu—O5	87.40 (6)
O1—Cu—N1	174.06 (6)
O1—Cu—N2	107.40 (6)
O3—Cu—O5	167.05 (6)
O3—Cu—N1	86.33 (5)
O3—Cu—N2	95.28 (6)
O5—Cu—N1	89.57 (5)
O5—Cu—N2	95.87 (5)
N1—Cu—N2	77.98 (6)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O5—H5C⋯O2ⁱ	0.88	1.86	2.714 (2)	166
O5—H5B⋯O4ⁱⁱ	0.89	1.72	2.605 (2)	175

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

This project was sponsored by the K. C. Wong Magna Fund in Ningbo University, the Expert Project of Key Basic Research of the Ministry of Science and Technology of China (grant No. 2003CCA00800), and the Ningbo Municipal Natural Science Foundation (grant No. 2006 A610061).

supplementary crystallographic information

Comment

We reported a structure of the copper-dmp complex aqua-(2,9-dimethyl-1,10-phenanthroline-κ²N:N')-diromato-copper(II) previously, which crystallizes in space group Pna2₁ (Pan, et al.,2005). On repeating the experiment recently, to our surprise, we found a new polyporph, (I), that had crystallized in the space group P2₁/c.

The crystal structure of the title compound is very similar to the previously reported complex, built up by the [Cu(dmp)(H₂O)(HCOO)₂] complex molecules. The Cu atoms are each square pyramidally coordinated by two N atoms of one dmp ligand, three O atoms of two formate anions and one water molecule with the N2 atom of the dmp ligand at the apical position. The apical and basal Cu—N bond distances are 2.280 (1) and 2.033 (2) Å, respectively. The Cu—O bond distances to the formate anions are 1.945 (1) and 1.955 (1) Å, slightly longer than that to the water molecule (1.973 (1) Å). Suggesting that the formate anions possess better coordinating capability to the water molecule in the structure, which also show no significant difference from the isomer crystal structure that reported by us. The Cu atom is shifted by 0.153 (1) Å from the equatorial plane through N1, O1, O3 and O5 atoms towards the apical N2 atom. Through the intermolecular hydrogen bond the complex molecules are link into double chains with the chelating dmp ligands extending parallelly on one side along [010]. The substituted phenanthroline ligands of one double chain protrude into the grooves between adjacent aromatic planes of the neighboring double chain, yielding two-dimensional layers parallel to (100). It is found that the assembly of the double chains is due to interchain π-π stacking interactions between the dmp ligands (mean interplanar distance: 3.59 Å).

Experimental

Dropwise addition of 2.0 ml (1.0 M) Na₂CO₃ to an aqueous solution of 0.075 g (0.442 mmol) CuCl₂.2H₂O in 5.0 ml H₂O yielded pale blue deposit, which was separated by centrifugation and washed with doubly distilled water until no Cl^- anions are detectable in the supernatant. The precipitate was then added to a solution of 0.100 g (0.442 mmol) 2,9-dimethyl-1,10-phenanthroline in a mixed solvent consisting of 15 ml H₂O and 15 ml me thanol. To the mixture 1.77 ml (1.0 M) formic acid was dropped and the precipitate was slowly dissolved under continuous stirring. The resulting blue solution was allowed to stand at room temperature, and slow evaporation for 10 days afforded blue plate crystals.