Poly[methyl­amine-μ-oxalato-copper(II)]

Keene, T.D.; Hursthouse, M.B.; Price, D.J.

doi:10.1107/S1600536806016679

metal-organic compounds

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ISSN: 2056-9890

Volume 62| Part 6| June 2006| Pages m1373-m1375

https://doi.org/10.1107/S1600536806016679

Poly[methylamine-μ-oxalato-copper(II)]

Tony D. Keene,^a Michael B. Hursthouse ^b and Daniel J. Price ^a ^*

^aWestCHEM, Department of Chemistry, University of Glasgow, University Avenue, Glasgow G12 8QQ, Scotland, and ^bSchool of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, England
^*Correspondence e-mail: danielp@chem.gla.ac.uk

(Received 2 May 2006; accepted 5 May 2006; online 24 May 2006)

The six-coordinate copper(II) ions in the title compound, [Cu(C₂O₄)(CH₅N)], experience a Jahn–Teller distortion. The structure is a two-dimensional coordination network, with three crystallographically independent oxalate ions, two of them centrosymmetric, bridging Cu^II ions in three different coordination modes. Each Cu ion is also coordinated by methylamine which is involved in both intra- and interlayer hydrogen bonding.

Comment

The oxalate ligand is known for its chelating and bridging coordination modes. It is used by magnetochemists to mediate significant exchange interactions and can result in magnetically ordered materials (Coronado et al., 2000 ; Decurtins et al., 1993 ; Demunno et al., 1995 ; Hursthouse et al., 2004 ; Julve et al., 1984 ; Keene et al., 2004 ; Mathoniere et al., 1996 ; Price et al., 2001 ). We present here the structure of [Cu(ox)(CH₃NH₂)] (ox = oxalate), (I).

The asymmetric unit of (I) contains two Cu atoms, two methylamine molecules, and one complete and two halves of oxalate anions (Fig. 1). The Cu^II cations each have a CuNO₅ coordination and show a large Jahn–Teller-induced tetragonal elongation. While the coordination environment of each Cu^II ion is very similar (Table 1), the coordination of the three oxalate ions differs significantly (Fig. 2). The structure of (I) is a complex two-dimensional coordination network that can best be viewed by initially considering only the short Cu—O/N contacts (<2.05 Å). The structure is built from two distinct copper oxalate chains. Chain A (Fig. 3) is formed from Cu1 and the oxalate containing C1 and C2; it consists of a simple alternation of these components, with a |–Cu1–oxB|_n repeat unit and a Cu⋯Cu separation of 5.530 (3) Å. Chain B (Fig. 3) is built from Cu2 and the crystallographically centrosymmetric oxalate anions containing C3 and C4. It has a more complex topology with a |–Cu2–oxA–Cu2–oxC–|_n repeat unit and alternating Cu⋯Cu separations of 5.537 (9) and 5.192 (9) Å. The longer Cu—O interactions link neighbouring chains into a corrugated two-dimensional structure in the bc plane (Fig. 4). The coordinated methylamine displays both intra- and interlayer hydrogen bonding (Table 2).

Surprisingly, there are very few structures that contain copper and either methyl- or ethylamine. Chemically, the most similar compound with a known structure is [Cu(NH₃)(ox)] (Cavalca et al., 1972 ). Indeed, the structure of this compound shows remarkable similarity to that of (I). [Cu(NH₃)(ox)] also has a two-dimensional character, being built from Cu(ox) chains with the type B structure described above. Here, neighbouring chains are linked through the long Cu—O interactions into a two-dimensional sheet structure, with a topology that is different from that seen in (I).

Figure 1
Fig. 1

. The asymmetric unit of (I)

and selected symmetry-equivalent atoms, showing the coordination of both metal ions and ligands. Displacement ellipsoids are drawn at the 40% probability level and H atoms have been omitted for clarity. [Symmetry codes: (i) 1 − x, −y, −z; (ii) 1 − x, −y, 1 − z; (iii) x, $[{1\over 2}]$ − y, $[{1\over 2}]$ + z; (iv) x, $[{1\over 2}]$ − y, − $[{1\over 2}]$ + z].

Figure 2
Schematic illustration of the three oxalate coordination modes seen in (I)

Figure 3
Two types of copper oxalate chain (A top and B bottom) from which the extended structure is built.

Figure 4
The complex two-dimensional Cu(ox) network, viewed along the a axis.

Experimental

Single crystals of (I) were synthesized by dissolving synthetic mooloolite, viz. [Cu(ox)]·0.33H₂O (1.000 g, 6.35 mmol), in an aqueous methylamine solution (20 ml, 40% w/w). The resultant dark-blue solution was further diluted with distilled water to a volume of 100 ml and left to evaporate. Blue crystals of (I) formed as a minor product amongst a large proportion of finely divided [Cu(ox)]·0.33H₂O.

Crystal data

[Cu(C₂O₄)(CH₅N)]
M_r = 365.24
Monoclinic, P 2₁ /c
a = 9.421 (8) Å
b = 12.668 (12) Å
c = 9.392 (7) Å
β = 102.53 (7)°
V = 1094.1 (16) Å³
Z = 4
D_x = 2.217 Mg m⁻³
Mo Kα radiation
μ = 3.92 mm⁻¹
T = 293 (2) K
Block, blue
0.04 × 0.03 × 0.03 mm

Data collection

Nonius KappaCCD diffractometer
φ and ω scans
Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ) T_min = 0.859, T_max = 0.891
11196 measured reflections
2525 independent reflections
1816 reflections with I > 2σ(I)
R_int = 0.076
θ_max = 27.7°

Refinement

Refinement on F²
R[F² > 2σ(F²)] = 0.057
wR(F²) = 0.130
S = 1.08
2525 reflections
163 parameters
H-atom parameters constrained
w = 1/[σ²(F_o²) + (0.0482P)² + 2.4064P] where P = (F_o² + 2F_c²)/3
(Δ/σ)_max < 0.001
Δρ_max = 0.53 e Å⁻³
Δρ_min = −0.79 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Cu1—O1	1.955 (4)
Cu1—N1	1.992 (5)
Cu1—O4ⁱ	2.004 (4)
Cu1—O3	2.025 (4)
Cu1—O2ⁱ	2.307 (4)
Cu2—O7	1.967 (4)
Cu2—N2	1.974 (5)
Cu2—O5	1.994 (4)
Cu2—O6ⁱⁱ	2.002 (4)
Cu2—O8ⁱⁱⁱ	2.311 (4)

O1—Cu1—N1	91.98 (18)
N1—Cu1—O4ⁱ	91.02 (17)
O1—Cu1—O3	83.91 (15)
O4ⁱ—Cu1—O3	93.74 (15)
O1—Cu1—O2ⁱ	97.03 (15)
N1—Cu1—O2ⁱ	98.67 (18)
O4ⁱ—Cu1—O2ⁱ	78.06 (15)
O3—Cu1—O2ⁱ	89.74 (16)
O7—Cu2—N2	92.53 (19)
O7—Cu2—O5	93.08 (16)
N2—Cu2—O6ⁱⁱ	90.85 (18)
O5—Cu2—O6ⁱⁱ	84.50 (16)
O7—Cu2—O8ⁱⁱⁱ	78.20 (15)
N2—Cu2—O8ⁱⁱⁱ	100.3 (2)
O5—Cu2—O8ⁱⁱⁱ	89.80 (18)
O6ⁱⁱ—Cu2—O8ⁱⁱⁱ	95.65 (16)
Symmetry codes: (i) $[x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]$ ; (ii) -x+1, -y, -z; (iii) -x+1, -y, -z+1; (iv) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ .

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯O1^v	0.9	2.22	3.042 (7)	153
N1—H1B⋯O6^vi	0.9	2.39	3.256 (7)	161
N2—H2B⋯O4	0.9	2.42	3.137 (7)	137
Symmetry codes: (v) -x, -y, -z+1; (vi) x, y, z+1.

H atoms were positioned geometrically, with N—H = 0.90 Å for amine H and C—H = 0.96 Å for methyl H atoms, and were constrained to ride on their parent atoms, with U_iso(H) = xU_eq(C,N), where x = 1.2 for amine H and x = 1.5 for methyl H atoms.

Data collection: DENZO (Otwinowski & Minor, 1997 ) and COLLECT (Hooft, 1998 ); cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SIR92 (Altomare et al., 1993 ) in WinGX (Farrugia, 1999 ); program(s) used to refine structure: SHELXS97 (Sheldrick, 1997 ) in WinGX; molecular graphics: DIAMOND (Brandenburg, 1999 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536806016679/hk2039sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536806016679/hk2039Isup2.hkl

Computing details top

Data collection: DENZO (Otwinowski & Minor, 1997); cell refinement: DENZO and COLLECT (Hooft, 1998); data reduction: DENZO and COLLECT; program(s) used to solve structure: SIR92 (Altomare et al., 1993) in WinGX (Farrugia, 1999)'; program(s) used to refine structure: SHELXS97 (Sheldrick, 1997) in WinGX'; molecular graphics: DIAMOND (Brandenburg, 1999).

Poly[methylamine-µ₃-oxalato-copper(II)] top

Crystal data top

[Cu(C₂O₄)(CH₅N)]	F(000) = 728
M_r = 365.24	D_x = 2.217 Mg m⁻³
Monoclinic, P2₁/c	Melting point: N/A K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 9.421 (8) Å	Cell parameters from 3698 reflections
b = 12.668 (12) Å	θ = 2.9–27.5°
c = 9.392 (7) Å	µ = 3.92 mm⁻¹
β = 102.53 (7)°	T = 566 K
V = 1094.1 (16) Å³	Block, blue
Z = 4	0.04 × 0.03 × 0.03 mm

Data collection top

Nonius KappaCCD diffractometer	1816 reflections with I > 2σ(I)
φ and ω scans	R_int = 0.076
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	θ_max = 27.7°, θ_min = 3.2°
T_min = 0.859, T_max = 0.891	h = −10→12
11196 measured reflections	k = −16→14
2525 independent reflections	l = −10→12

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.057	w = 1/[σ²(F_o²) + (0.0482P)² + 2.4064P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.130	(Δ/σ)_max < 0.001
S = 1.08	Δρ_max = 0.53 e Å⁻³
2525 reflections	Δρ_min = −0.79 e Å⁻³
163 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Cu1	0.19173 (7)	0.14720 (5)	0.67560 (7)	0.0302 (2)
Cu2	0.49291 (8)	0.10215 (6)	0.23795 (7)	0.0328 (2)
O1	0.0744 (4)	0.1432 (3)	0.4765 (4)	0.0332 (9)
O2	0.0588 (4)	0.2250 (3)	0.2635 (4)	0.0368 (9)
O3	0.3028 (4)	0.2615 (3)	0.5955 (4)	0.0318 (9)
O4	0.3051 (4)	0.3347 (3)	0.3809 (4)	0.0308 (9)
O5	0.3811 (4)	−0.0131 (3)	0.1192 (4)	0.0347 (9)
O6	0.3845 (4)	−0.0980 (3)	−0.0886 (4)	0.0347 (9)
O7	0.3817 (4)	0.0902 (3)	0.3919 (4)	0.0346 (9)
O8	0.3739 (4)	0.0225 (3)	0.6094 (4)	0.0414 (10)
N1	0.0929 (5)	0.0199 (4)	0.7323 (5)	0.0349 (11)
H1A	0.0647	−0.0205	0.6523	0.042*
H1B	0.159	−0.0174	0.7963	0.042*
N2	0.5906 (5)	0.2327 (4)	0.3227 (5)	0.0410 (12)
H2A	0.5823	0.2806	0.2506	0.049*
H2B	0.5412	0.2579	0.3873	0.049*
C1	0.1168 (6)	0.2084 (4)	0.3928 (6)	0.0278 (11)
C2	0.2527 (6)	0.2730 (4)	0.4620 (6)	0.0289 (12)
C3	0.4327 (6)	−0.0315 (4)	0.0094 (6)	0.0288 (12)
C4	0.4293 (6)	0.0320 (4)	0.5010 (6)	0.0312 (12)
C5	−0.0350 (9)	0.0366 (7)	0.7974 (10)	0.082 (3)
H5A	−0.0722	−0.0305	0.8199	0.123*
H5B	−0.109	0.0737	0.7293	0.123*
H5C	−0.0069	0.0774	0.8851	0.123*
C6	0.7426 (9)	0.2267 (7)	0.3953 (11)	0.091 (3)
H6A	0.7761	0.2954	0.4308	0.137*
H6B	0.7985	0.2025	0.3275	0.137*
H6C	0.754	0.1783	0.4756	0.137*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.0351 (4)	0.0295 (4)	0.0264 (4)	−0.0041 (3)	0.0077 (3)	0.0003 (3)
Cu2	0.0383 (4)	0.0320 (4)	0.0306 (4)	−0.0011 (3)	0.0132 (3)	−0.0022 (3)
O1	0.032 (2)	0.033 (2)	0.033 (2)	−0.0071 (18)	0.0063 (16)	0.0037 (16)
O2	0.042 (2)	0.039 (2)	0.028 (2)	−0.0024 (19)	0.0053 (17)	0.0027 (17)
O3	0.037 (2)	0.033 (2)	0.025 (2)	−0.0045 (17)	0.0043 (16)	0.0024 (16)
O4	0.034 (2)	0.030 (2)	0.027 (2)	−0.0002 (16)	0.0045 (16)	0.0014 (15)
O5	0.041 (2)	0.037 (2)	0.030 (2)	−0.0049 (19)	0.0163 (17)	−0.0047 (17)
O6	0.042 (2)	0.036 (2)	0.028 (2)	−0.0060 (18)	0.0129 (17)	−0.0022 (17)
O7	0.041 (2)	0.035 (2)	0.030 (2)	0.0112 (18)	0.0115 (17)	0.0070 (16)
O8	0.046 (3)	0.046 (2)	0.037 (2)	0.013 (2)	0.0203 (19)	0.0100 (19)
N1	0.040 (3)	0.033 (3)	0.032 (2)	−0.005 (2)	0.009 (2)	0.000 (2)
N2	0.045 (3)	0.033 (3)	0.047 (3)	−0.002 (2)	0.015 (2)	−0.007 (2)
C1	0.029 (3)	0.027 (3)	0.029 (3)	0.001 (2)	0.010 (2)	0.001 (2)
C2	0.031 (3)	0.029 (3)	0.029 (3)	0.003 (2)	0.011 (2)	0.000 (2)
C3	0.034 (3)	0.027 (3)	0.025 (3)	0.003 (2)	0.007 (2)	0.005 (2)
C4	0.033 (3)	0.029 (3)	0.032 (3)	0.001 (2)	0.007 (2)	0.000 (2)
C5	0.091 (6)	0.059 (5)	0.119 (7)	−0.023 (5)	0.071 (6)	−0.024 (5)
C6	0.041 (5)	0.076 (6)	0.150 (9)	−0.003 (4)	0.004 (5)	−0.044 (6)

Geometric parameters (Å, º) top

Cu1—O1	1.955 (4)	C1—O1	1.264 (6)
Cu1—N1	1.992 (5)	C2—O3	1.249 (6)
Cu1—O4ⁱ	2.004 (4)	C2—O4	1.265 (6)
Cu1—O3	2.025 (4)	C2—C1	1.539 (8)
Cu1—O2ⁱ	2.307 (4)	C3—O5	1.254 (6)
Cu2—O7	1.967 (4)	C3—O6	1.258 (6)
Cu2—N2	1.974 (5)	C3—C3ⁱⁱ	1.541 (11)
Cu2—O5	1.994 (4)	C4—O8	1.247 (6)
Cu2—O6ⁱⁱ	2.002 (4)	C4—O7	1.262 (6)
Cu2—O8ⁱⁱⁱ	2.311 (4)	C4—C4ⁱⁱⁱ	1.564 (11)
O2—Cu1^iv	2.307 (4)	C5—N1	1.480 (9)
O4—Cu1^iv	2.004 (4)	C5—H5A	0.96
O6—Cu2ⁱⁱ	2.002 (4)	C5—H5B	0.96
O8—Cu2ⁱⁱⁱ	2.311 (4)	C5—H5C	0.96
N1—H1A	0.9	C6—N2	1.448 (9)
N1—H1B	0.9	C6—H6A	0.96
N2—H2A	0.9	C6—H6B	0.96
N2—H2B	0.9	C6—H6C	0.96
C1—O2	1.237 (6)

O1—Cu1—N1	91.98 (18)	Cu1—N1—H1B	107.9
O1—Cu1—O4ⁱ	174.59 (16)	H1A—N1—H1B	107.2
N1—Cu1—O4ⁱ	91.02 (17)	C6—N2—Cu2	118.2 (5)
O1—Cu1—O3	83.91 (15)	C6—N2—H2A	107.8
N1—Cu1—O3	171.04 (17)	Cu2—N2—H2A	107.8
O4ⁱ—Cu1—O3	93.74 (15)	C6—N2—H2B	107.8
O1—Cu1—O2ⁱ	97.03 (15)	Cu2—N2—H2B	107.8
N1—Cu1—O2ⁱ	98.67 (18)	H2A—N2—H2B	107.1
O4ⁱ—Cu1—O2ⁱ	78.06 (15)	O2—C1—O1	126.1 (5)
O3—Cu1—O2ⁱ	89.74 (16)	O2—C1—C2	118.3 (5)
O7—Cu2—N2	92.53 (19)	O1—C1—C2	115.5 (5)
O7—Cu2—O5	93.08 (16)	O3—C2—O4	124.4 (5)
N2—Cu2—O5	169.25 (19)	O3—C2—C1	117.5 (5)
O7—Cu2—O6ⁱⁱ	173.43 (16)	O4—C2—C1	118.2 (5)
N2—Cu2—O6ⁱⁱ	90.85 (18)	O5—C3—O6	125.7 (5)
O5—Cu2—O6ⁱⁱ	84.50 (16)	O5—C3—C3ⁱⁱ	118.3 (6)
O7—Cu2—O8ⁱⁱⁱ	78.20 (15)	O6—C3—C3ⁱⁱ	116.0 (6)
N2—Cu2—O8ⁱⁱⁱ	100.3 (2)	O8—C4—O7	125.5 (5)
O5—Cu2—O8ⁱⁱⁱ	89.80 (18)	O8—C4—C4ⁱⁱⁱ	117.9 (6)
O6ⁱⁱ—Cu2—O8ⁱⁱⁱ	95.65 (16)	O7—C4—C4ⁱⁱⁱ	116.5 (6)
C1—O1—Cu1	112.9 (3)	N1—C5—H5A	109.5
C1—O2—Cu1^iv	108.2 (3)	N1—C5—H5B	109.5
C2—O3—Cu1	110.0 (3)	H5A—C5—H5B	109.5
C2—O4—Cu1^iv	117.0 (3)	N1—C5—H5C	109.5
C3—O5—Cu2	110.1 (3)	H5A—C5—H5C	109.5
C3—O6—Cu2ⁱⁱ	111.0 (3)	H5B—C5—H5C	109.5
C4—O7—Cu2	119.3 (4)	N2—C6—H6A	109.5
C4—O8—Cu2ⁱⁱⁱ	107.8 (3)	N2—C6—H6B	109.5
C5—N1—Cu1	117.7 (4)	H6A—C6—H6B	109.5
C5—N1—H1A	107.9	N2—C6—H6C	109.5
Cu1—N1—H1A	107.9	H6A—C6—H6C	109.5
C5—N1—H1B	107.9	H6B—C6—H6C	109.5

Symmetry codes: (i) x, −y+1/2, z+1/2; (ii) −x+1, −y, −z; (iii) −x+1, −y, −z+1; (iv) x, −y+1/2, z−1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O1^v	0.9	2.22	3.042 (7)	153
N1—H1B···O6^vi	0.9	2.39	3.256 (7)	161
N2—H2B···O4	0.9	2.42	3.137 (7)	137

Symmetry codes: (v) −x, −y, −z+1; (vi) x, y, z+1.

Acknowledgements

The authors are grateful to the EPSRC, the University of Glasgow and the University of Southampton for financial support.

References

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