Diethyl 2,2′-bi­pyridine-4,4′-di­carboxyl­ate

Rillema, D.P.; Moore, C.; KomReddy, V.

doi:10.1107/S2414314616015479

organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 10| October 2016| x161547

https://doi.org/10.1107/S2414314616015479

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Diethyl 2,2′-bipyridine-4,4′-dicarboxylate

D. Paul Rillema,^a ^* Curtis Moore ^b and Venugopal KomReddy ^a

^aDepartment of Chemistry, Wichita State University, Wichita, KS 67260, USA, and ^bCrystallographic laboratory, University of California, San Diego, LaJolla, CA 92093, USA
^*Correspondence e-mail: paul.rillema@wichita.edu

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 20 September 2016; accepted 3 October 2016; online 4 October 2016)

The title bipyridine derivative, C₁₆H₁₆N₂O₄, crystallized with two half molecules in the asymmetric unit. The whole molecules (A and B) are generated by inversion symmetry with the mid-points of the bridging C—C bonds of the bipyridine units being located on crystallographic inversion centers. In the crystal, molecules are linked by C—H⋯O hydrogen bonds, forming sheets parallel to (120). The sheets are linked by C—H⋯N hydrogen bonds, forming a three-dimensional framework.

Keywords: crystal structure; bipyridine; dicarboxylate; hydrogen bonding; bidentate ligand; electron-withdrawing group.

CCDC reference: 1507876

Structure description

Dimmine ligands, such as the title compound, have been used to coordinate to transition metals, viz. Ru²⁺, Pt²⁺, and Re¹⁺, for use in solar energy conversion studies due to their excellent electronic properties (Cruz et al., 2010 ; Rillema et al., 2015 ; Villegas et al., 2005 ). Upon photoexcitation, electrons are channeled from the metal center to the diimmine ligand on its pathway to the ground state.

The molecular structure of the two independent molecules of the title compound (A and B) are illustrated in Fig. 1. In both molecules, the two pyridine rings are arranged such that the pyridine N atoms are trans to one another. Molecule A is more planar than molecule B, with the ethyl carboxylate group [C—C—O—C(=O)] being inclined to the pyridine ring by 2.11 (15)° in A, and 5.69 (15)° in B.

Figure 1
The molecular structure of the two independent molecules (A and B) of the title compound, showing the atom labeling [the unlabeled atoms are related to the labeled atoms by the symmetry code (−x + 1, −y, −z) for molecule A, and (−x + 1, −y + 1, −z + 1) for molecule B]. Displacement ellipsoids are drawn at the 50% probability level.

The bond lengths and bond angles of the title free ligand are basically the same as those observed for the coordinated ligand in Pt(bph)(4,4′-diethoxycarbonyl-2,2′-bipyridine) (Rillema et al., 2015). Upon coordination to transition metals, the two pyridine rings have the pyridine N atoms cis to one another, resulting in π–π delocalization over the whole ligand.

In the crystal, molecules are linked by C—H⋯O hydrogen bonds (Table 1), forming sheets parallel to (120), as illustrated in Fig. 2. The sheets are linked by C—H⋯N hydrogen bonds, forming a three-dimensional framework (Table 1 and Fig. 3).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯O1′ⁱ	0.95	2.49	3.421 (3)	167
C8—H8B⋯O1′ⁱⁱ	0.98	2.52	3.465 (3)	161
C5′—H5′⋯O1ⁱⁱⁱ	0.95	2.47	3.404 (3)	167
C8′—H8′A⋯O1^iv	0.98	2.58	3.518 (3)	161
C7—H7B⋯N1′	0.99	2.58	3.565 (4)	172
Symmetry codes: (i) x+1, y-1, z; (ii) -x, -y+1, -z+1; (iii) x+1, y, z; (iv) -x, -y+1, -z.

Figure 2
A view normal to plane (120) of the crystal packing of the title compound (molecule A is blue and molecule B is red). The hydrogen bonds are shown as dashed lines (see Table 1

), and, for clarity, only the H atoms involved in hydrogen bonding have been included.

Figure 3
A view along the c axis of the crystal packing of the title compound (molecule A is blue and molecule B is red). The hydrogen bonds are shown as dashed lines (see Table 1

), and, for clarity, only the H atoms involved in hydrogen bonding have been included.

Synthesis and crystallization

The title compound was prepared in two steps according to previously published procedures. In step one, 4,4′-dimethyl-2,2′-bipyridine, purchased commercially, was oxidized forming 4,4′-dicarboxy-2,2′-bipyridine (Oki et al., 1995 ). In step two, the dicarboxy compound was converted to the diethoxycarbonyl derivative (Ciana et al., 1990 ). The vapor diffusion technique was used to obtain single crystals of the title compound. It was dissolved in dichloromethane and placed in a center vial, while the outer vial contained methanol.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₆H₁₆N₂O₄
M_r	300.31
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	100
a, b, c (Å)	3.9059 (8), 13.493 (3), 13.767 (3)
α, β, γ (°)	92.212 (7), 93.163 (7), 93.016 (7)
V (Å³)	722.8 (3)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.10
Crystal size (mm)	0.13 × 0.08 × 0.06

Data collection
Diffractometer	Bruker APEXII Ultra
Absorption correction	Multi-scan (SADABS; Bruker, 2013 )
T_min, T_max	0.066, 0.092
No. of measured, independent and observed [I > 2σ(I)] reflections	10150, 2664, 1699
R_int	0.054
(sin θ/λ)_max (Å⁻¹)	0.603

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.057, 0.141, 1.02
No. of reflections	2664
No. of parameters	201
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.59, −0.26
Computer programs: APEX2 and SAINT (Bruker, 2013), SHEXLS2014 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), OLEX2 (Dolomanov et al., 2009 ) and Mercury (Macrae et al., 2008 ).

Structural data

CCDC reference: 1507876

Crystal structure: contains datablocks I, Global. DOI: https://doi.org/10.1107/S2414314616015479/su4079sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314616015479/su4079Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2414314616015479/su4079Isup3.cml

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2013); cell refinement: SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHEXLS2014 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009) and Mercury (Macrae et al., 2008); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

Diethyl 2,2'-bipyridine-4,4'-dicarboxylate top

Crystal data top

C₁₆H₁₆N₂O₄	Z = 2
M_r = 300.31	F(000) = 316
Triclinic, P1	D_x = 1.380 Mg m⁻³
a = 3.9059 (8) Å	Mo Kα radiation, λ = 0.71073 Å
b = 13.493 (3) Å	Cell parameters from 2248 reflections
c = 13.767 (3) Å	θ = 3.0–25.0°
α = 92.212 (7)°	µ = 0.10 mm⁻¹
β = 93.163 (7)°	T = 100 K
γ = 93.016 (7)°	Plate, colorless
V = 722.8 (3) Å³	0.13 × 0.08 × 0.06 mm

Data collection top

Bruker APEXII Ultra diffractometer	2664 independent reflections
Radiation source: Micro Focus Rotating Anode, Bruker TXS	1699 reflections with I > 2σ(I)
Double Bounce Multilayer Mirrors monochromator	R_int = 0.054
Detector resolution: 7.9 pixels mm^-1	θ_max = 25.4°, θ_min = 1.5°
ω and φ scans	h = −4→4
Absorption correction: multi-scan (SADABS; Bruker, 2013)	k = −16→16
T_min = 0.066, T_max = 0.092	l = −16→16
10150 measured reflections

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)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.141	H-atom parameters constrained
S = 1.02	w = 1/[σ²(F_o²) + (0.0623P)² + 0.352P] where P = (F_o² + 2F_c²)/3
2664 reflections	(Δ/σ)_max < 0.001
201 parameters	Δρ_max = 0.59 e Å⁻³
0 restraints	Δρ_min = −0.26 e Å⁻³

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.

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

	x	y	z	U_iso*/U_eq
N1	0.6443 (6)	−0.08269 (16)	0.09213 (16)	0.0229 (6)
O1	0.1227 (5)	0.21648 (14)	0.24091 (14)	0.0322 (5)
O2	0.2666 (5)	0.12418 (13)	0.36775 (13)	0.0267 (5)
C1	0.5052 (6)	−0.00246 (18)	0.05424 (19)	0.0213 (6)
C2	0.3798 (7)	0.0728 (2)	0.1117 (2)	0.0227 (6)
H2	0.2878	0.1291	0.0827	0.027*
C3	0.3909 (7)	0.06454 (19)	0.2116 (2)	0.0230 (7)
C4	0.5353 (7)	−0.0181 (2)	0.2512 (2)	0.0250 (7)
H4	0.5496	−0.0255	0.3196	0.030*
C5	0.6573 (7)	−0.0889 (2)	0.1889 (2)	0.0243 (7)
H5	0.7558	−0.1452	0.2163	0.029*
C6	0.2460 (7)	0.1439 (2)	0.2732 (2)	0.0238 (7)
C7	0.1308 (7)	0.1979 (2)	0.43362 (19)	0.0268 (7)
H7A	−0.1157	0.2057	0.4167	0.032*
H7B	0.2562	0.2631	0.4290	0.032*
C8	0.1788 (8)	0.1608 (2)	0.5350 (2)	0.0322 (8)
H8A	0.0535	0.0963	0.5385	0.048*
H8B	0.0904	0.2084	0.5817	0.048*
H8C	0.4237	0.1535	0.5508	0.048*
N1'	0.6531 (6)	0.41872 (16)	0.40638 (16)	0.0225 (6)
O1'	0.1233 (5)	0.71739 (14)	0.26347 (13)	0.0307 (5)
O2'	0.2484 (5)	0.62205 (13)	0.13410 (13)	0.0257 (5)
C1'	0.5100 (6)	0.49830 (18)	0.44587 (19)	0.0210 (6)
C2'	0.3829 (7)	0.57364 (19)	0.39046 (19)	0.0214 (6)
H2'	0.2889	0.6296	0.4209	0.026*
C3'	0.3960 (7)	0.56565 (19)	0.2899 (2)	0.0213 (6)
C4'	0.5453 (7)	0.4843 (2)	0.2487 (2)	0.0231 (7)
H4'	0.5623	0.4774	0.1803	0.028*
C5'	0.6691 (7)	0.4135 (2)	0.3096 (2)	0.0241 (7)
H5'	0.7713	0.3580	0.2810	0.029*
C6'	0.2446 (7)	0.6440 (2)	0.2295 (2)	0.0219 (6)
C7'	0.0956 (8)	0.6935 (2)	0.0684 (2)	0.0325 (7)
H7'A	0.2167	0.7597	0.0789	0.039*
H7'B	−0.1497	0.6999	0.0808	0.039*
C8'	0.1316 (9)	0.6543 (2)	−0.0342 (2)	0.0401 (8)
H8'A	0.0362	0.7007	−0.0802	0.060*
H8'B	0.0070	0.5894	−0.0441	0.060*
H8'C	0.3750	0.6473	−0.0452	0.060*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.0252 (13)	0.0172 (12)	0.0269 (14)	0.0071 (10)	0.0006 (10)	0.0006 (10)
O1	0.0430 (13)	0.0242 (11)	0.0301 (12)	0.0145 (10)	−0.0005 (10)	−0.0027 (9)
O2	0.0306 (11)	0.0268 (11)	0.0235 (11)	0.0094 (9)	0.0026 (8)	−0.0026 (8)
C1	0.0165 (14)	0.0190 (15)	0.0278 (15)	0.0007 (12)	−0.0008 (12)	−0.0017 (12)
C2	0.0215 (15)	0.0172 (14)	0.0293 (17)	0.0037 (12)	−0.0014 (12)	0.0005 (12)
C3	0.0185 (15)	0.0202 (15)	0.0301 (17)	0.0034 (12)	−0.0001 (12)	−0.0015 (12)
C4	0.0248 (16)	0.0262 (16)	0.0246 (16)	0.0055 (13)	0.0021 (13)	0.0008 (13)
C5	0.0242 (15)	0.0193 (15)	0.0305 (17)	0.0093 (12)	0.0016 (12)	0.0038 (12)
C6	0.0201 (15)	0.0250 (16)	0.0258 (17)	0.0035 (13)	−0.0015 (12)	−0.0023 (13)
C7	0.0290 (16)	0.0262 (15)	0.0255 (16)	0.0089 (13)	0.0022 (12)	−0.0072 (12)
C8	0.0318 (18)	0.0359 (18)	0.0294 (18)	0.0072 (14)	0.0050 (13)	−0.0032 (14)
N1'	0.0224 (13)	0.0187 (12)	0.0264 (14)	0.0045 (10)	0.0011 (10)	−0.0022 (10)
O1'	0.0428 (13)	0.0249 (11)	0.0259 (12)	0.0169 (10)	0.0033 (9)	−0.0007 (9)
O2'	0.0327 (11)	0.0242 (11)	0.0206 (11)	0.0105 (9)	−0.0005 (8)	−0.0023 (8)
C1'	0.0195 (15)	0.0157 (15)	0.0278 (15)	0.0015 (12)	0.0021 (12)	−0.0021 (12)
C2'	0.0220 (15)	0.0157 (14)	0.0269 (17)	0.0057 (12)	0.0047 (12)	−0.0030 (12)
C3'	0.0176 (14)	0.0177 (14)	0.0282 (17)	0.0015 (12)	0.0024 (12)	−0.0046 (12)
C4'	0.0235 (15)	0.0240 (15)	0.0221 (15)	0.0053 (13)	0.0010 (12)	−0.0006 (13)
C5'	0.0228 (15)	0.0184 (14)	0.0312 (18)	0.0066 (12)	0.0033 (12)	−0.0067 (12)
C6'	0.0194 (15)	0.0208 (15)	0.0252 (17)	0.0008 (12)	0.0003 (12)	−0.0004 (12)
C7'	0.0352 (18)	0.0308 (17)	0.0319 (18)	0.0045 (14)	0.0061 (14)	−0.0019 (14)
C8'	0.044 (2)	0.047 (2)	0.0287 (19)	0.0099 (16)	0.0006 (15)	−0.0062 (15)

Geometric parameters (Å, º) top

N1—C1	1.347 (3)	N1'—C1'	1.346 (3)
N1—C5	1.336 (3)	N1'—C5'	1.336 (3)
O1—C6	1.203 (3)	O1'—C6'	1.209 (3)
O2—C6	1.338 (3)	O2'—C6'	1.336 (3)
O2—C7	1.460 (3)	O2'—C7'	1.474 (3)
C1—C1ⁱ	1.496 (5)	C1'—C1'ⁱⁱ	1.496 (5)
C1—C2	1.389 (4)	C1'—C2'	1.390 (4)
C2—H2	0.9500	C2'—H2'	0.9500
C2—C3	1.382 (4)	C2'—C3'	1.388 (4)
C3—C4	1.392 (4)	C3'—C4'	1.386 (4)
C3—C6	1.494 (4)	C3'—C6'	1.496 (4)
C4—H4	0.9500	C4'—H4'	0.9500
C4—C5	1.381 (4)	C4'—C5'	1.384 (4)
C5—H5	0.9500	C5'—H5'	0.9500
C7—H7A	0.9900	C7'—H7'A	0.9900
C7—H7B	0.9900	C7'—H7'B	0.9900
C7—C8	1.507 (4)	C7'—C8'	1.505 (4)
C8—H8A	0.9800	C8'—H8'A	0.9800
C8—H8B	0.9800	C8'—H8'B	0.9800
C8—H8C	0.9800	C8'—H8'C	0.9800

C5—N1—C1	117.6 (2)	C5'—N1'—C1'	117.3 (2)
C6—O2—C7	115.9 (2)	C6'—O2'—C7'	116.5 (2)
N1—C1—C1ⁱ	116.4 (3)	N1'—C1'—C1'ⁱⁱ	116.4 (3)
N1—C1—C2	122.5 (2)	N1'—C1'—C2'	122.8 (2)
C2—C1—C1ⁱ	121.1 (3)	C2'—C1'—C1'ⁱⁱ	120.8 (3)
C1—C2—H2	120.4	C1'—C2'—H2'	120.6
C3—C2—C1	119.1 (2)	C3'—C2'—C1'	118.8 (2)
C3—C2—H2	120.4	C3'—C2'—H2'	120.6
C2—C3—C4	118.6 (2)	C2'—C3'—C6'	119.1 (2)
C2—C3—C6	119.1 (2)	C4'—C3'—C2'	118.7 (2)
C4—C3—C6	122.3 (3)	C4'—C3'—C6'	122.1 (2)
C3—C4—H4	120.7	C3'—C4'—H4'	120.8
C5—C4—C3	118.5 (3)	C5'—C4'—C3'	118.5 (3)
C5—C4—H4	120.7	C5'—C4'—H4'	120.8
N1—C5—C4	123.5 (2)	N1'—C5'—C4'	123.8 (3)
N1—C5—H5	118.2	N1'—C5'—H5'	118.1
C4—C5—H5	118.2	C4'—C5'—H5'	118.1
O1—C6—O2	124.3 (3)	O1'—C6'—O2'	123.9 (2)
O1—C6—C3	123.6 (3)	O1'—C6'—C3'	123.6 (2)
O2—C6—C3	112.1 (2)	O2'—C6'—C3'	112.4 (2)
O2—C7—H7A	110.3	O2'—C7'—H7'A	110.3
O2—C7—H7B	110.3	O2'—C7'—H7'B	110.3
O2—C7—C8	106.9 (2)	O2'—C7'—C8'	107.2 (2)
H7A—C7—H7B	108.6	H7'A—C7'—H7'B	108.5
C8—C7—H7A	110.3	C8'—C7'—H7'A	110.3
C8—C7—H7B	110.3	C8'—C7'—H7'B	110.3
C7—C8—H8A	109.5	C7'—C8'—H8'A	109.5
C7—C8—H8B	109.5	C7'—C8'—H8'B	109.5
C7—C8—H8C	109.5	C7'—C8'—H8'C	109.5
H8A—C8—H8B	109.5	H8'A—C8'—H8'B	109.5
H8A—C8—H8C	109.5	H8'A—C8'—H8'C	109.5
H8B—C8—H8C	109.5	H8'B—C8'—H8'C	109.5

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···O1′ⁱⁱⁱ	0.95	2.49	3.421 (3)	167
C8—H8B···O1′^iv	0.98	2.52	3.465 (3)	161
C5′—H5′···O1^v	0.95	2.47	3.404 (3)	167
C8′—H8′A···O1^vi	0.98	2.58	3.518 (3)	161
C7—H7B···N1′	0.99	2.58	3.565 (4)	172

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

Acknowledgements

We are grateful for support from the National Science Foundation (EPSCOR), the Wichita State University Office of Research, and the Department of Energy.

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