5-Ethyl L-glutamate

In the title compound, C₇H₁₃NO₄, there are two independent mol­ecules in the asymmetric unit. All bond lengths and angles in the mol­ecules are in normal ranges. The ψ¹ and ψ² torsion angles are 159.9 (4) and −23.4 (5)°, respectively, in the first molecule, and the ψ³ and ψ⁴ torsion angles 157.7 (4) and −26.7 (5)°, respectively, in the second. Each of the independent mol­ecules has a different comformation. The translationally and screw-related mol­ecules are connected by N—H...O hydrogen bonds, forming a two-dimensional network parallel to the ac plane.

Key indicators

• Single-crystal X-ray study
• T = 273 K
• Mean [sigma](C-C) = 0.008 Å
• R factor = 0.060
• wR factor = 0.178
• Data-to-parameter ratio = 8.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.09
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       3.40 Ratio
PLAT220_ALERT_2_C Large Non-Solvent    O     Ueq(max)/Ueq(min) ...       2.84 Ratio
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.68 Ratio
PLAT220_ALERT_2_C Large Non-Solvent    O     Ueq(max)/Ueq(min) ...       2.65 Ratio
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.98 Ratio
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.18 Ratio
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C5
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C12
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.17
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          8

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           26.00
           From the CIF: _reflns_number_total               1927
           Count of symmetry unique reflns         1943
           Completeness (_total/calc)             99.18%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         0
           Fraction of Friedel pairs measured     0.000
           Are heavy atom types Z>Si present         no

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
  12 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   8 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: APEX (Bruker, 2001); cell refinement: SAINT-Plus (Bruker, 2001); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL-NT (Bruker, 2001); software used to prepare material for publication: SHELXTL-NT.

5-Ethyl L-glutamate

Crystal data

C7H13NO4	F(000) = 376
Mr = 175.18	Dx = 1.319 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2yb	Cell parameters from 1376 reflections
a = 9.691 (3) Å	θ = 3.1–21.6°
b = 5.2631 (17) Å	µ = 0.11 mm^−1
c = 17.297 (6) Å	T = 273 K
β = 90.752 (5)°	Plate, colorless
V = 882.2 (5) Å^3	0.50 × 0.49 × 0.02 mm
Z = 4

Data collection

Bruker SMART-APEX CCD area-detector diffractometer	1927 independent reflections
Radiation source: fine-focus sealed tube	1546 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.027
φ and ω scans	θmax = 26.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→11
Tmin = 0.948, Tmax = 0.998	k = −6→5
5098 measured reflections	l = −21→20

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.060	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.178	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.0984P)^2 + 0.2865P] where P = (Fo^2 + 2Fc^2)/3
1927 reflections	(Δ/σ)max < 0.001
221 parameters	Δρmax = 0.50 e Å^−3
2 restraints	Δρmin = −0.24 e Å^−3

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.7724 (4)	−0.0270 (8)	0.5897 (2)	0.0336 (9)
C2	0.6316 (4)	−0.1298 (8)	0.6153 (2)	0.0355 (9)
H2	0.5601	−0.0151	0.5951	0.043*
C3	0.6165 (5)	−0.1438 (10)	0.7029 (3)	0.0539 (12)
H3A	0.7005	−0.2124	0.7258	0.065*
H3B	0.5411	−0.2571	0.7154	0.065*
C4	0.5885 (6)	0.1205 (12)	0.7366 (3)	0.0652 (14)
H4A	0.6702	0.2248	0.7308	0.078*
H4B	0.5141	0.1996	0.7073	0.078*
C5	0.5520 (6)	0.1137 (13)	0.8168 (4)	0.0680 (15)
C6	0.4263 (7)	0.3222 (14)	0.9150 (3)	0.088 (2)
H6A	0.5059	0.3626	0.9473	0.106*
H6B	0.3865	0.1646	0.9333	0.106*
C7	0.3237 (7)	0.5285 (15)	0.9193 (5)	0.114 (3)
H7A	0.2434	0.4833	0.8892	0.171*
H7B	0.3627	0.6823	0.8992	0.171*
H7C	0.2981	0.5540	0.9721	0.171*
C8	0.7212 (4)	0.8910 (8)	0.3978 (2)	0.0354 (9)
C9	0.8542 (4)	0.7526 (8)	0.3775 (2)	0.0372 (9)
H9	0.9323	0.8696	0.3836	0.045*
C10	0.8450 (4)	0.6629 (10)	0.2931 (2)	0.0487 (11)
H10A	0.7639	0.5565	0.2867	0.058*
H10B	0.8333	0.8099	0.2598	0.058*
C11	0.9692 (5)	0.5170 (13)	0.2678 (3)	0.0631 (15)
H11A	0.9766	0.3629	0.2984	0.076*
H11B	1.0510	0.6182	0.2781	0.076*
C12	0.9650 (5)	0.4466 (13)	0.1833 (3)	0.0615 (14)
C13	1.0697 (6)	0.1975 (16)	0.0882 (3)	0.0791 (19)
H13A	1.0952	0.3434	0.0572	0.095*
H13B	0.9827	0.1315	0.0684	0.095*
C14	1.1764 (7)	0.0022 (17)	0.0839 (4)	0.095 (2)
H14A	1.1447	−0.1498	0.1087	0.143*
H14B	1.2588	0.0615	0.1096	0.143*
H14C	1.1959	−0.0333	0.0307	0.143*
N1	0.6080 (3)	−0.3841 (7)	0.5805 (2)	0.0414 (9)
H1A	0.6709	−0.4926	0.5988	0.062*
H1B	0.6149	−0.3736	0.5293	0.062*
H1C	0.5240	−0.4388	0.5925	0.062*
N2	0.8749 (3)	0.5308 (7)	0.43012 (19)	0.0352 (8)
H2A	0.8158	0.4082	0.4172	0.053*
H2B	0.8605	0.5786	0.4787	0.053*
H2C	0.9609	0.4734	0.4258	0.053*
O1	0.7927 (3)	0.2056 (6)	0.5943 (2)	0.0522 (9)
O2	0.8608 (2)	−0.1875 (6)	0.56902 (16)	0.0397 (7)
O3	0.5922 (6)	−0.0364 (12)	0.8655 (3)	0.113 (2)
O4	0.4675 (4)	0.2946 (10)	0.8362 (2)	0.0795 (13)
O5	0.7104 (3)	1.1172 (6)	0.3778 (2)	0.0554 (9)
O6	0.6278 (2)	0.7623 (6)	0.42901 (17)	0.0426 (8)
O7	0.8926 (5)	0.5428 (12)	0.1356 (2)	0.112 (2)
O8	1.0561 (4)	0.2709 (9)	0.16801 (19)	0.0755 (13)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0214 (16)	0.037 (2)	0.042 (2)	−0.0026 (17)	0.0025 (14)	0.0027 (18)
C2	0.0216 (16)	0.032 (2)	0.053 (2)	0.0031 (16)	0.0046 (15)	0.0030 (19)
C3	0.060 (3)	0.048 (3)	0.054 (3)	−0.006 (2)	0.012 (2)	0.004 (2)
C4	0.074 (3)	0.060 (3)	0.062 (3)	0.001 (3)	0.006 (3)	0.001 (3)
C5	0.061 (3)	0.058 (3)	0.085 (4)	0.009 (3)	0.011 (3)	−0.007 (3)
C6	0.089 (4)	0.095 (5)	0.083 (4)	0.002 (4)	0.026 (3)	−0.019 (4)
C7	0.099 (5)	0.114 (7)	0.130 (6)	−0.011 (5)	0.047 (5)	−0.044 (6)
C8	0.0260 (18)	0.033 (2)	0.047 (2)	0.0059 (17)	−0.0028 (16)	−0.0060 (18)
C9	0.0238 (17)	0.037 (2)	0.051 (2)	0.0047 (17)	0.0038 (16)	−0.0004 (19)
C10	0.037 (2)	0.059 (3)	0.049 (2)	0.013 (2)	0.0036 (17)	−0.003 (2)
C11	0.055 (3)	0.082 (4)	0.053 (3)	0.023 (3)	0.002 (2)	−0.011 (3)
C12	0.051 (3)	0.082 (4)	0.052 (3)	0.016 (3)	0.006 (2)	−0.005 (3)
C13	0.073 (4)	0.108 (5)	0.056 (3)	0.013 (4)	0.007 (3)	−0.019 (4)
C14	0.079 (4)	0.100 (5)	0.107 (5)	0.004 (4)	0.023 (4)	−0.041 (5)
N1	0.0219 (15)	0.046 (2)	0.057 (2)	−0.0117 (16)	0.0005 (14)	0.0060 (18)
N2	0.0219 (14)	0.0352 (18)	0.0486 (18)	0.0067 (13)	0.0026 (13)	−0.0040 (15)
O1	0.0417 (17)	0.0298 (17)	0.085 (2)	−0.0054 (13)	0.0095 (15)	−0.0027 (16)
O2	0.0211 (12)	0.0390 (16)	0.0593 (17)	−0.0041 (12)	0.0058 (11)	−0.0111 (14)
O3	0.159 (5)	0.109 (4)	0.072 (3)	0.063 (4)	0.019 (3)	0.016 (3)
O4	0.079 (3)	0.097 (3)	0.062 (2)	0.029 (3)	0.0120 (19)	−0.009 (2)
O5	0.0422 (17)	0.0332 (18)	0.091 (2)	0.0096 (14)	−0.0055 (16)	0.0040 (16)
O6	0.0211 (12)	0.0472 (18)	0.0595 (17)	0.0039 (13)	0.0045 (12)	−0.0009 (15)
O7	0.122 (4)	0.155 (6)	0.060 (2)	0.080 (4)	−0.018 (2)	−0.018 (3)
O8	0.068 (2)	0.103 (4)	0.056 (2)	0.033 (3)	0.0055 (17)	−0.013 (2)

Geometric parameters (Å, º)

C1—O1	1.243 (5)	C9—N2	1.492 (5)
C1—O2	1.258 (5)	C9—C10	1.537 (6)
C1—C2	1.538 (5)	C9—H9	0.9800
C2—N1	1.484 (6)	C10—C11	1.498 (6)
C2—C3	1.526 (6)	C10—H10A	0.9700
C2—H2	0.9800	C10—H10B	0.9700
C3—C4	1.534 (8)	C11—C12	1.507 (7)
C3—H3A	0.9700	C11—H11A	0.9700
C3—H3B	0.9700	C11—H11B	0.9700
C4—C5	1.437 (8)	C12—O7	1.190 (6)
C4—H4A	0.9700	C12—O8	1.308 (7)
C4—H4B	0.9700	C13—O8	1.442 (6)
C5—O3	1.215 (8)	C13—C14	1.461 (10)
C5—O4	1.303 (7)	C13—H13A	0.9700
C6—O4	1.432 (6)	C13—H13B	0.9700
C6—C7	1.475 (5)	C14—H14A	0.9600
C6—H6A	0.9700	C14—H14B	0.9600
C6—H6B	0.9700	C14—H14C	0.9600
C7—H7A	0.9600	N1—H1A	0.8900
C7—H7B	0.9600	N1—H1B	0.8900
C7—H7C	0.9600	N1—H1C	0.8900
C8—O5	1.244 (6)	N2—H2A	0.8900
C8—O6	1.257 (5)	N2—H2B	0.8900
C8—C9	1.526 (5)	N2—H2C	0.8900
O1—C1—O2	124.9 (4)	C8—C9—H9	109.2
O1—C1—C2	117.9 (4)	C10—C9—H9	109.2
O2—C1—C2	117.1 (4)	C11—C10—C9	113.4 (4)
N1—C2—C3	110.0 (3)	C11—C10—H10A	108.9
N1—C2—C1	109.5 (3)	C9—C10—H10A	108.9
C3—C2—C1	113.6 (3)	C11—C10—H10B	108.9
N1—C2—H2	107.9	C9—C10—H10B	108.9
C3—C2—H2	107.9	H10A—C10—H10B	107.7
C1—C2—H2	107.9	C10—C11—C12	113.4 (4)
C2—C3—C4	110.7 (4)	C10—C11—H11A	108.9
C2—C3—H3A	109.5	C12—C11—H11A	108.9
C4—C3—H3A	109.5	C10—C11—H11B	108.9
C2—C3—H3B	109.5	C12—C11—H11B	108.9
C4—C3—H3B	109.5	H11A—C11—H11B	107.7
H3A—C3—H3B	108.1	O7—C12—O8	123.6 (5)
C5—C4—C3	113.1 (5)	O7—C12—C11	125.2 (5)
C5—C4—H4A	109.0	O8—C12—C11	111.2 (4)
C3—C4—H4A	109.0	O8—C13—C14	108.1 (5)
C5—C4—H4B	109.0	O8—C13—H13A	110.1
C3—C4—H4B	109.0	C14—C13—H13A	110.1
H4A—C4—H4B	107.8	O8—C13—H13B	110.1
O3—C5—O4	119.6 (6)	C14—C13—H13B	110.1
O3—C5—C4	127.2 (6)	H13A—C13—H13B	108.4
O4—C5—C4	113.2 (6)	C13—C14—H14A	109.5
O4—C6—C7	108.6 (6)	C13—C14—H14B	109.5
O4—C6—H6A	110.0	H14A—C14—H14B	109.5
C7—C6—H6A	110.0	C13—C14—H14C	109.5
O4—C6—H6B	110.0	H14A—C14—H14C	109.5
C7—C6—H6B	110.0	H14B—C14—H14C	109.5
H6A—C6—H6B	108.3	C2—N1—H1A	109.5
C6—C7—H7A	109.5	C2—N1—H1B	109.5
C6—C7—H7B	109.5	H1A—N1—H1B	109.5
H7A—C7—H7B	109.5	C2—N1—H1C	109.5
C6—C7—H7C	109.5	H1A—N1—H1C	109.5
H7A—C7—H7C	109.5	H1B—N1—H1C	109.5
H7B—C7—H7C	109.5	C9—N2—H2A	109.5
O5—C8—O6	125.3 (4)	C9—N2—H2B	109.5
O5—C8—C9	117.4 (4)	H2A—N2—H2B	109.5
O6—C8—C9	117.2 (4)	C9—N2—H2C	109.5
N2—C9—C8	109.9 (3)	H2A—N2—H2C	109.5
N2—C9—C10	110.2 (3)	H2B—N2—H2C	109.5
C8—C9—C10	109.0 (3)	C5—O4—C6	120.2 (5)
N2—C9—H9	109.2	C12—O8—C13	117.0 (5)
O1—C1—C2—N1	159.9 (4)	O6—C8—C9—C10	94.1 (4)
O2—C1—C2—N1	−23.4 (5)	N2—C9—C10—C11	−57.5 (5)
O1—C1—C2—C3	−76.8 (5)	C8—C9—C10—C11	−178.2 (4)
O2—C1—C2—C3	100.0 (4)	C9—C10—C11—C12	−175.5 (5)
N1—C2—C3—C4	−159.6 (4)	C10—C11—C12—O7	17.9 (10)
C1—C2—C3—C4	77.3 (5)	C10—C11—C12—O8	−164.6 (5)
C2—C3—C4—C5	170.8 (4)	O3—C5—O4—C6	2.3 (10)
C3—C4—C5—O3	32.3 (10)	C4—C5—O4—C6	−176.9 (6)
C3—C4—C5—O4	−148.6 (5)	C7—C6—O4—C5	−176.0 (6)
O5—C8—C9—N2	157.7 (4)	O7—C12—O8—C13	1.5 (10)
O6—C8—C9—N2	−26.7 (5)	C11—C12—O8—C13	−176.0 (5)
O5—C8—C9—C10	−81.5 (5)	C14—C13—O8—C12	179.6 (6)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O5^i	0.89	1.96	2.840 (5)	170
N2—H2B···O2^ii	0.89	1.99	2.828 (4)	157
N2—H2C···O2^iii	0.89	1.93	2.807 (4)	170
N1—H1A···O1^i	0.89	1.98	2.813 (5)	155
N1—H1B···O6^i	0.89	1.88	2.741 (4)	161
N1—H1C···O6^iv	0.89	2.18	2.950 (4)	144
N1—H1C···O5^iv	0.89	2.35	3.178 (4)	154

Symmetry codes: (i) x, y−1, z; (ii) x, y+1, z; (iii) −x+2, y+1/2, −z+1; (iv) −x+1, y−3/2, −z+1.