organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

Redetermined crystal structure of N-(β-carb­­oxy­eth­yl)-α-isoleucine

CROSSMARK_Color_square_no_text.svg

aDepartment of Physics, Thiagarajar College, Madurai 625 009, Tamil Nadu, India
*Correspondence e-mail: mailtorvkk@yahoo.com

Edited by R. F. Baggio, Comisión Nacional de Energía Atómica, Argentina (Received 28 July 2015; accepted 31 July 2015; online 22 August 2015)

Redetermination of the crystal structure of N-(β-carb­oxy­eth­yl)-α-isoleucine, C9H18N2O3, reported earlier by Nehls et al. [Acta Cryst. (2013), E69, o172–o173], was undertaken in which the ionization state assigned to the mol­ecule as unionized has been modified as zwitterionic in the present work. Single-crystal X-ray intensity data obtained from freshly grown crystals and freely refining the amino H atoms provide enhanced refinement and structural parameters, particularly the hydrogen-bonding scheme. N—H⋯O hydrogen bonds dominate the inter­molecular inter­actions along with a C—H⋯O hydrogen bond. The inter­molecular inter­action pattern is a three-dimensional network. The structure was refined as a two-component perfect inversion twin.

1. Related literature

For earlier work on the crystal structure of N-(β-carb­oxy­eth­yl)-α-isoleucine, see: Nehls et al. (2013[Nehls, I., Hanebeck, O., Becker, R. & Emmerling, F. (2013). Acta Cryst. E69, o172-o173.]). For the crystal structure of L-isoleucine and its indolylacetyl derivative, respectively, see Görbitz & Dalhus (1996[Görbitz, C. H. & Dalhus, B. (1996). Acta Cryst. C52, 1464-1466.]); Kojić-Prodić et al. (1991[Kojić-Prodić, B., Nigović, B., Horvatić, D., Ružić-Toroš, Ž., Magnus, V., Duax, W. L., Stezowski, J. J. & Bresciani-Pahor, N. (1991). Acta Cryst. B47, 107-115.]). For the importance of freely refining the positions of amino-group H atoms, see: Görbitz (2014[Görbitz, C. H. (2014). Acta Cryst. E70, 341-343.]). For absolute configuration and structure parameters, see Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.]); Flack & Bernardinelli (2000[Flack, H. D. & Bernardinelli, G. (2000). J. Appl. Cryst. 33, 1143-1148.]); Hooft et al. (2008[Hooft, R. W. W., Straver, L. H. & Spek, A. L. (2008). J. Appl. Cryst. 41, 96-103.]); Spek (2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); Parsons et al. (2013[Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249-259.]). For chiral and achiral crystal structures, see Flack (2003[Flack, H. D. (2003). Helv. Chim. Acta, 86, 905-921.]).

[Scheme 1]

2. Experimental

2.1. Crystal data

  • C9H18N2O3

  • Mr = 202.25

  • Orthorhombic, P 21 21 21

  • a = 5.2996 (5) Å

  • b = 9.0053 (7) Å

  • c = 23.211 (2) Å

  • V = 1107.75 (17) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.09 mm−1

  • T = 293 K

  • 0.26 × 0.18 × 0.10 mm

2.2. Data collection

  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.97, Tmax = 0.99

  • 22904 measured reflections

  • 3127 independent reflections

  • 2538 reflections with I > 2σ(I)

  • Rint = 0.036

2.3. Refinement

  • R[F2 > 2σ(F2)] = 0.042

  • wR(F2) = 0.102

  • S = 1.08

  • 3127 reflections

  • 146 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.30 e Å−3

  • Δρmin = −0.19 e Å−3

  • Absolute structure: refined as a perfect inversion twin.

  • Absolute structure parameter: fixed at 0.5 and not refined

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N1—H1N1⋯O2i 0.89 (2) 1.96 (2) 2.7772 (19) 152 (2)
N1—H2N1⋯O1ii 0.88 (2) 1.83 (2) 2.7047 (19) 174 (2)
N2—H1N2⋯O3iii 0.90 (3) 2.11 (3) 2.970 (3) 161 (3)
N2—H2N2⋯O3ii 0.84 (3) 2.34 (3) 3.092 (3) 149 (2)
C2—H2⋯O1iv 0.98 2.53 3.469 (2) 160
Symmetry codes: (i) [-x+1, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]; (ii) x+1, y, z; (iii) [x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+2]; (iv) [-x+1, y+{\script{1\over 2}}, -z+{\script{3\over 2}}].

Data collection: APEX2 (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2009[Bruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS2013 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]); molecular graphics: PLATON (Spek, 2009[Spek, A. L. (2009). Acta Cryst. D65, 148-155.]); software used to prepare material for publication: SHELXL2014.

Supporting information


Introduction top

Amino acids in their free form exist as 'zwitterions' in their crystals with a deprotonated carboxyl group (COO–) and a protonated NH3+ group (NH2+ in proline). Any deviation from this general preferences of amino acids is worth careful considerations. The motivation for the present work is the unionized state reported by Nehls et al., 2013, for the title compound in contrast to the usually preferred 'zwitterionic' state. In this context, redetermination of the crystal structure of the title compouned was undertaken.

Experimental top

Synthesis and crystallization top

For crystallization details, see Nehls et al. (2013).

Refinement top

Coordinates were refined for amino H atoms; other H atoms were positioned with idealized geometry, with fixed C— H = 0.98 (methyl), 0.99 (methyl­ene) or 1.00 Å (methine). Uiso(H) values were set at 1.2Ueq of the carrier atom or at 1.5Ueq for methyl and amino groups. The absolute configuration could not be determined by anomalous-dispersion effects in the X-ray diffraction measurements of the crystal, but assigned as L- based on an unchanged chiral centre in the synthetic procedure. The absoulte structure was refined as a perfect inversion twin.

Results and discussion top

Nehls et al., (2013) seem to have presumed an unionized state for the title compound with an undissociated carboxyl (COOH) and a deprotonated amino (NH) group. A scrutiny of the work by Nehls et al. revealed that all the H-atoms, including the donor group H atoms were assigned an idealized geometry and refined as riding on their respective non-H atoms to which they are attached. Redetermination of the crystal structure carried out by measuring X-ray intensity data from freshly grown crystals and freely refining the amino-H atoms clearly indicate that the title compound indeed exist as a zwitterion. The correct assignment of the ionized state provided enhanced refinement and structural parameters. Thus, the present redtermination demonstrates the importance of freely refining donor group hydrogens. The S,S (equivalently L-) absolute configuration is deduced from the synthetic pathway as the starting material involved L-isoleucine. The absoulte structure was refined as a perfect inversion twin in order that the Flack x (Flack, 1983; Flack & Bernardinelli, 2000; Parsons et al., 2013) and Hooft y parameters (Spek, 2009) showed good agreement.

The correct assignment of the ionization state to the title compound as 'zwitterion' presents an acceptable description of the inter­molecular inter­action patterns with all the amino-H atoms participating in them. The carboxyl­ate O1 atom of the amino acid derivative participates in a strong head-to-tail N—H···O hydrogen bond characteristic of amino acids, in addition to a C—H···O hydrogen-bond as acceptor. This has consequently resulted in the lengthening of the C6—O1[1.253 (2)Å] bond compared to its counterpart C6—O2[1.234 (2)Å]. The carbamoyl group N2 and O3 form N—H···O hydrogen-bonds within themselves leading to C32(8) chains linking screw related molecules along the shortest a-axis. The respective amino and carboxyl­ate group N and O atoms form characteristic head-to-tail hydrogen-bonds leading to a layers parallel to the ab-plane. The inter­molecular inter­action pattern is a three-dimensional network dominated by N—H···O hydrogen bonds, in addition to a C—H···O hydrogen-bond involving the α-carbon atom (C2) as donor and the carboxyl­ate O1 as acceptor.

Related literature top

For earlier work on the crystal structure of N-(β-carboxyethyl)-α-isoleucine, see: Nehls et al. (2013). For the crystal structure of L-isoleucine and its indolylacetyl derivative, respectively, see Görbitz & Dalhus (1996); Kojić-Prodić et al. (1991). For the importance of freely refining the positions of amino-group H atoms, see: Görbitz (2014). For absolute configuration and structure parameters, see Flack (1983); Flack & Bernardinelli (2000); Hooft et al. (2008); Spek (2009); Parsons et al. (2013). For chiral and achiral crystal structures, see Flack (2003).

Structure description top

Amino acids in their free form exist as 'zwitterions' in their crystals with a deprotonated carboxyl group (COO–) and a protonated NH3+ group (NH2+ in proline). Any deviation from this general preferences of amino acids is worth careful considerations. The motivation for the present work is the unionized state reported by Nehls et al., 2013, for the title compound in contrast to the usually preferred 'zwitterionic' state. In this context, redetermination of the crystal structure of the title compouned was undertaken.

Nehls et al., (2013) seem to have presumed an unionized state for the title compound with an undissociated carboxyl (COOH) and a deprotonated amino (NH) group. A scrutiny of the work by Nehls et al. revealed that all the H-atoms, including the donor group H atoms were assigned an idealized geometry and refined as riding on their respective non-H atoms to which they are attached. Redetermination of the crystal structure carried out by measuring X-ray intensity data from freshly grown crystals and freely refining the amino-H atoms clearly indicate that the title compound indeed exist as a zwitterion. The correct assignment of the ionized state provided enhanced refinement and structural parameters. Thus, the present redtermination demonstrates the importance of freely refining donor group hydrogens. The S,S (equivalently L-) absolute configuration is deduced from the synthetic pathway as the starting material involved L-isoleucine. The absoulte structure was refined as a perfect inversion twin in order that the Flack x (Flack, 1983; Flack & Bernardinelli, 2000; Parsons et al., 2013) and Hooft y parameters (Spek, 2009) showed good agreement.

The correct assignment of the ionization state to the title compound as 'zwitterion' presents an acceptable description of the inter­molecular inter­action patterns with all the amino-H atoms participating in them. The carboxyl­ate O1 atom of the amino acid derivative participates in a strong head-to-tail N—H···O hydrogen bond characteristic of amino acids, in addition to a C—H···O hydrogen-bond as acceptor. This has consequently resulted in the lengthening of the C6—O1[1.253 (2)Å] bond compared to its counterpart C6—O2[1.234 (2)Å]. The carbamoyl group N2 and O3 form N—H···O hydrogen-bonds within themselves leading to C32(8) chains linking screw related molecules along the shortest a-axis. The respective amino and carboxyl­ate group N and O atoms form characteristic head-to-tail hydrogen-bonds leading to a layers parallel to the ab-plane. The inter­molecular inter­action pattern is a three-dimensional network dominated by N—H···O hydrogen bonds, in addition to a C—H···O hydrogen-bond involving the α-carbon atom (C2) as donor and the carboxyl­ate O1 as acceptor.

For earlier work on the crystal structure of N-(β-carboxyethyl)-α-isoleucine, see: Nehls et al. (2013). For the crystal structure of L-isoleucine and its indolylacetyl derivative, respectively, see Görbitz & Dalhus (1996); Kojić-Prodić et al. (1991). For the importance of freely refining the positions of amino-group H atoms, see: Görbitz (2014). For absolute configuration and structure parameters, see Flack (1983); Flack & Bernardinelli (2000); Hooft et al. (2008); Spek (2009); Parsons et al. (2013). For chiral and achiral crystal structures, see Flack (2003).

Synthesis and crystallization top

For crystallization details, see Nehls et al. (2013).

Refinement details top

Coordinates were refined for amino H atoms; other H atoms were positioned with idealized geometry, with fixed C— H = 0.98 (methyl), 0.99 (methyl­ene) or 1.00 Å (methine). Uiso(H) values were set at 1.2Ueq of the carrier atom or at 1.5Ueq for methyl and amino groups. The absolute configuration could not be determined by anomalous-dispersion effects in the X-ray diffraction measurements of the crystal, but assigned as L- based on an unchanged chiral centre in the synthetic procedure. The absoulte structure was refined as a perfect inversion twin.

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS2013 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

Figures top
[Figure 1] Fig. 1. Thermal ellipsoid plot of the title compound, showing the atom numbering scheme.
[Figure 2] Fig. 2. The characteristic head-to-tail N—H···O hydrogen bonds involving the carboxylate and the amino groups. Non pariticipating N-carboxyethl group atoms have been omitted for clarity.
[Figure 3] Fig. 3. Carbamoyl group N2 and O3 forming N—H···O hydrogen-bonds within themselves leading to C32(8) chains linking screw related molecules along the a axis.
(2S,3S)-2-[(2-Carbamoylethyl)azaniumyl]-3-methylpentanoate top
Crystal data top
C9H18N2O3F(000) = 440
Mr = 202.25Dx = 1.213 Mg m3
Dm = 1.21 Mg m3
Dm measured by floatation method
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
a = 5.2996 (5) ŵ = 0.09 mm1
b = 9.0053 (7) ÅT = 293 K
c = 23.211 (2) ÅNeedle, colourless
V = 1107.75 (17) Å30.26 × 0.18 × 0.10 mm
Z = 4
Data collection top
Bruker APEXII CCD
diffractometer
2538 reflections with I > 2σ(I)
ω and φ scansRint = 0.036
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
θmax = 29.9°, θmin = 2.4°
Tmin = 0.97, Tmax = 0.99h = 77
22904 measured reflectionsk = 1211
3127 independent reflectionsl = 3132
Refinement top
Refinement on F2Hydrogen site location: mixed
Least-squares matrix: fullH atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.042 w = 1/[σ2(Fo2) + (0.0479P)2 + 0.1014P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.102(Δ/σ)max < 0.001
S = 1.08Δρmax = 0.30 e Å3
3127 reflectionsΔρmin = 0.19 e Å3
146 parametersAbsolute structure: Refined as a perfect inversion twin.
0 restraintsAbsolute structure parameter: 0.5
Crystal data top
C9H18N2O3V = 1107.75 (17) Å3
Mr = 202.25Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 5.2996 (5) ŵ = 0.09 mm1
b = 9.0053 (7) ÅT = 293 K
c = 23.211 (2) Å0.26 × 0.18 × 0.10 mm
Data collection top
Bruker APEXII CCD
diffractometer
3127 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2009)
2538 reflections with I > 2σ(I)
Tmin = 0.97, Tmax = 0.99Rint = 0.036
22904 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.042H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.102Δρmax = 0.30 e Å3
S = 1.08Δρmin = 0.19 e Å3
3127 reflectionsAbsolute structure: Refined as a perfect inversion twin.
146 parametersAbsolute structure parameter: 0.5
0 restraints
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.

Refinement. Refined as a 2-component perfect inversion twin.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.2868 (2)0.54162 (13)0.74549 (7)0.0379 (4)
O20.2473 (3)0.77532 (13)0.71778 (7)0.0383 (4)
O30.6665 (3)0.6614 (2)0.94137 (7)0.0550 (5)
N10.7861 (3)0.57896 (16)0.76272 (6)0.0213 (3)
N21.0857 (4)0.6555 (3)0.95384 (9)0.0475 (5)
C50.7705 (8)0.7167 (5)0.55526 (12)0.0942 (12)
H5A0.94720.73570.56060.141*
H5B0.70170.78840.52900.141*
H5C0.74790.61880.53980.141*
C40.6370 (5)0.7281 (3)0.61215 (10)0.0506 (6)
H4A0.45840.71010.60620.061*
H4B0.65550.82850.62670.061*
C30.7352 (4)0.6194 (2)0.65736 (8)0.0329 (4)
H30.91990.62350.65580.040*
C60.6603 (6)0.4612 (3)0.64363 (10)0.0571 (7)
H6A0.72320.39610.67310.086*
H6B0.73040.43300.60710.086*
H6C0.47970.45400.64200.086*
C20.6583 (3)0.66957 (19)0.71782 (7)0.0224 (4)
H20.71230.77290.72270.027*
C10.3732 (3)0.66295 (19)0.72788 (8)0.0244 (4)
C70.7684 (4)0.6481 (2)0.82050 (8)0.0297 (4)
H7A0.59260.65360.83190.036*
H7B0.83400.74850.81870.036*
C80.9134 (4)0.5614 (2)0.86493 (8)0.0354 (5)
H8A1.09120.56110.85510.042*
H8B0.85470.45940.86550.042*
C90.8776 (4)0.6301 (2)0.92372 (8)0.0348 (4)
H1N10.723 (4)0.488 (2)0.7648 (9)0.029 (5)*
H2N10.947 (4)0.568 (2)0.7544 (9)0.027 (5)*
H2N21.228 (6)0.631 (3)0.9411 (11)0.051 (7)*
H1N21.082 (6)0.697 (3)0.9890 (13)0.064 (9)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0150 (6)0.0337 (7)0.0651 (10)0.0005 (5)0.0039 (6)0.0146 (6)
O20.0213 (7)0.0261 (6)0.0675 (10)0.0044 (6)0.0089 (7)0.0012 (6)
O30.0324 (8)0.0925 (14)0.0400 (9)0.0071 (9)0.0034 (7)0.0200 (8)
N10.0129 (6)0.0224 (7)0.0287 (8)0.0001 (5)0.0007 (5)0.0012 (6)
N20.0339 (11)0.0737 (15)0.0348 (10)0.0011 (10)0.0030 (8)0.0149 (10)
C50.101 (3)0.142 (3)0.0405 (15)0.019 (3)0.0009 (16)0.0249 (17)
C40.0549 (15)0.0597 (14)0.0371 (11)0.0110 (12)0.0076 (11)0.0114 (11)
C30.0225 (9)0.0464 (11)0.0299 (9)0.0034 (9)0.0010 (8)0.0003 (8)
C60.080 (2)0.0488 (14)0.0423 (13)0.0016 (14)0.0050 (13)0.0135 (11)
C20.0141 (7)0.0235 (8)0.0296 (8)0.0012 (6)0.0007 (6)0.0019 (7)
C10.0142 (7)0.0270 (8)0.0319 (9)0.0006 (7)0.0014 (7)0.0027 (7)
C70.0266 (9)0.0320 (9)0.0305 (9)0.0073 (8)0.0013 (7)0.0079 (7)
C80.0320 (11)0.0428 (11)0.0313 (10)0.0088 (9)0.0057 (8)0.0070 (9)
C90.0319 (10)0.0430 (11)0.0295 (9)0.0018 (9)0.0019 (9)0.0027 (8)
Geometric parameters (Å, º) top
O1—C11.253 (2)C4—H4B0.9700
O2—C11.234 (2)C3—C61.513 (3)
O3—C91.224 (3)C3—C21.530 (2)
N1—C71.481 (2)C3—H30.9800
N1—C21.487 (2)C6—H6A0.9600
N1—H1N10.89 (2)C6—H6B0.9600
N1—H2N10.88 (2)C6—H6C0.9600
N2—C91.326 (3)C2—C11.530 (2)
N2—H2N20.84 (3)C2—H20.9800
N2—H1N20.90 (3)C7—C81.504 (3)
C5—C41.502 (4)C7—H7A0.9700
C5—H5A0.9600C7—H7B0.9700
C5—H5B0.9600C8—C91.510 (3)
C5—H5C0.9600C8—H8A0.9700
C4—C31.527 (3)C8—H8B0.9700
C4—H4A0.9700
C7—N1—C2112.03 (13)H6A—C6—H6B109.5
C7—N1—H1N1108.3 (13)C3—C6—H6C109.5
C2—N1—H1N1111.9 (14)H6A—C6—H6C109.5
C7—N1—H2N1107.9 (14)H6B—C6—H6C109.5
C2—N1—H2N1110.4 (14)N1—C2—C3111.07 (14)
H1N1—N1—H2N1106.1 (19)N1—C2—C1108.74 (14)
C9—N2—H2N2121.0 (18)C3—C2—C1113.06 (15)
C9—N2—H1N2122 (2)N1—C2—H2107.9
H2N2—N2—H1N2117 (3)C3—C2—H2107.9
C4—C5—H5A109.5C1—C2—H2107.9
C4—C5—H5B109.5O2—C1—O1125.42 (16)
H5A—C5—H5B109.5O2—C1—C2118.20 (15)
C4—C5—H5C109.5O1—C1—C2116.38 (15)
H5A—C5—H5C109.5N1—C7—C8111.73 (14)
H5B—C5—H5C109.5N1—C7—H7A109.3
C5—C4—C3113.6 (2)C8—C7—H7A109.3
C5—C4—H4A108.9N1—C7—H7B109.3
C3—C4—H4A108.9C8—C7—H7B109.3
C5—C4—H4B108.9H7A—C7—H7B107.9
C3—C4—H4B108.9C7—C8—C9110.04 (16)
H4A—C4—H4B107.7C7—C8—H8A109.7
C6—C3—C4111.70 (19)C9—C8—H8A109.7
C6—C3—C2113.68 (17)C7—C8—H8B109.7
C4—C3—C2110.48 (17)C9—C8—H8B109.7
C6—C3—H3106.9H8A—C8—H8B108.2
C4—C3—H3106.9O3—C9—N2122.98 (19)
C2—C3—H3106.9O3—C9—C8120.75 (18)
C3—C6—H6A109.5N2—C9—C8116.27 (19)
C3—C6—H6B109.5
C5—C4—C3—C671.2 (3)N1—C2—C1—O2144.24 (16)
C5—C4—C3—C2161.2 (2)C3—C2—C1—O291.9 (2)
C7—N1—C2—C3165.30 (14)N1—C2—C1—O136.3 (2)
C7—N1—C2—C169.67 (18)C3—C2—C1—O187.5 (2)
C6—C3—C2—N162.6 (2)C2—N1—C7—C8176.01 (15)
C4—C3—C2—N1170.95 (17)N1—C7—C8—C9176.58 (17)
C6—C3—C2—C160.0 (2)C7—C8—C9—O348.8 (3)
C4—C3—C2—C166.5 (2)C7—C8—C9—N2130.4 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N1···O2i0.89 (2)1.96 (2)2.7772 (19)152 (2)
N1—H2N1···O1ii0.88 (2)1.83 (2)2.7047 (19)174 (2)
N2—H1N2···O3iii0.90 (3)2.11 (3)2.970 (3)161 (3)
N2—H2N2···O3ii0.84 (3)2.34 (3)3.092 (3)149 (2)
C2—H2···O1iv0.982.533.469 (2)160
Symmetry codes: (i) x+1, y1/2, z+3/2; (ii) x+1, y, z; (iii) x+1/2, y+3/2, z+2; (iv) x+1, y+1/2, z+3/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H1N1···O2i0.89 (2)1.96 (2)2.7772 (19)152 (2)
N1—H2N1···O1ii0.88 (2)1.83 (2)2.7047 (19)174 (2)
N2—H1N2···O3iii0.90 (3)2.11 (3)2.970 (3)161 (3)
N2—H2N2···O3ii0.84 (3)2.34 (3)3.092 (3)149 (2)
C2—H2···O1iv0.982.533.469 (2)160.4
Symmetry codes: (i) x+1, y1/2, z+3/2; (ii) x+1, y, z; (iii) x+1/2, y+3/2, z+2; (iv) x+1, y+1/2, z+3/2.
 

Acknowledgements

The authors thank the Sophisticated Analytical Instrumentation Facility (SAIF), Indian Institue of Technology, Chennai, for the data collection.

References

First citationBruker (2009). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationFlack, H. D. (1983). Acta Cryst. A39, 876–881.  CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationFlack, H. D. (2003). Helv. Chim. Acta, 86, 905–921.  Web of Science CrossRef CAS Google Scholar
First citationFlack, H. D. & Bernardinelli, G. (2000). J. Appl. Cryst. 33, 1143–1148.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationGörbitz, C. H. (2014). Acta Cryst. E70, 341–343.  CSD CrossRef IUCr Journals Google Scholar
First citationGörbitz, C. H. & Dalhus, B. (1996). Acta Cryst. C52, 1464–1466.  CSD CrossRef Web of Science IUCr Journals Google Scholar
First citationHooft, R. W. W., Straver, L. H. & Spek, A. L. (2008). J. Appl. Cryst. 41, 96–103.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationKojić-Prodić, B., Nigović, B., Horvatić, D., Ružić-Toroš, Ž., Magnus, V., Duax, W. L., Stezowski, J. J. & Bresciani-Pahor, N. (1991). Acta Cryst. B47, 107–115.  CSD CrossRef IUCr Journals Google Scholar
First citationNehls, I., Hanebeck, O., Becker, R. & Emmerling, F. (2013). Acta Cryst. E69, o172–o173.  CSD CrossRef IUCr Journals Google Scholar
First citationParsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
First citationSpek, A. L. (2009). Acta Cryst. D65, 148–155.  Web of Science CrossRef CAS IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds