Crystal structures of the isomeric dipeptides L-glycyl-L-me­thio­nine and L-me­thionyl-L-glycine

The zwitterionic, isomeric, title compounds, Gly-Met and Met-Gly are me­thio­nine-containing dipeptides, which show very different conformations in the solid state.

Computing details

L-Glycyl-L-methionine (Gly-Met)

Crystal data

C7H14N2O3S	F(000) = 220
Mr = 206.26	Dx = 1.369 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
a = 6.2517 (2) Å	Cell parameters from 5067 reflections
b = 5.4935 (2) Å	θ = 2.8–40.1°
c = 14.5686 (6) Å	µ = 0.30 mm^−1
β = 91.147 (4)°	T = 90 K
V = 500.24 (3) Å^3	Plate, colourless
Z = 2	0.38 × 0.29 × 0.03 mm

Data collection

Bruker Kappa APEXII DUO CCD diffractometer	5922 independent reflections
Radiation source: fine-focus sealed tube	5356 reflections with I > 2σ(I)
TRIUMPH curved graphite monochromator	Rint = 0.026
φ and ω scans	θmax = 40.3°, θmin = 2.8°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −9→11
Tmin = 0.836, Tmax = 0.991	k = −9→9
11393 measured reflections	l = −26→26

Refinement

Refinement on F^2	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.033	w = 1/[σ^2(Fo^2) + (0.0417P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.079	(Δ/σ)max = 0.001
S = 1.04	Δρmax = 0.53 e Å^−3
5922 reflections	Δρmin = −0.30 e Å^−3
131 parameters	Absolute structure: Flack x determined using 2141 quotients [(I^+)-(I^-)]/[(I^+)+(I^-)] Parsons et al. (2013)
1 restraint	Absolute structure parameter: 0.02 (2)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
S1	−0.20146 (4)	0.44474 (6)	0.42848 (2)	0.01468 (6)
O1	0.69310 (13)	0.51962 (16)	0.16278 (6)	0.01361 (15)
O2	0.19251 (13)	0.15688 (15)	0.17287 (6)	0.01189 (14)
O3	0.17853 (13)	0.50896 (16)	0.09597 (6)	0.01188 (13)
N1	0.87880 (15)	0.89936 (16)	0.08355 (7)	0.00999 (15)
H11N	0.913 (3)	0.757 (4)	0.0948 (13)	0.015*
H12N	0.981 (3)	0.994 (4)	0.1072 (12)	0.015*
H13N	0.865 (3)	0.912 (4)	0.0257 (13)	0.015*
N2	0.42247 (14)	0.73584 (17)	0.22578 (7)	0.00962 (14)
H2N	0.353 (3)	0.863 (4)	0.2171 (13)	0.012*
C1	0.67091 (16)	0.9440 (2)	0.12752 (8)	0.01317 (16)
H1D	0.563279	0.995080	0.080609	0.016*
H1E	0.686342	1.076254	0.173329	0.016*
C2	0.59716 (16)	0.71258 (19)	0.17425 (7)	0.00938 (15)
C3	0.30874 (16)	0.51654 (19)	0.25172 (7)	0.00890 (15)
H3	0.410296	0.406010	0.285399	0.011*
C4	0.22080 (16)	0.38311 (18)	0.16587 (7)	0.00835 (15)
C5	0.12523 (18)	0.5846 (2)	0.31603 (8)	0.01112 (17)
H5A	0.184307	0.675550	0.369448	0.013*
H5B	0.023082	0.692558	0.282903	0.013*
C6	0.00678 (19)	0.3600 (2)	0.34991 (8)	0.01315 (18)
H6A	0.109333	0.249024	0.381309	0.016*
H6B	−0.057507	0.272165	0.296822	0.016*
C7	−0.3286 (2)	0.1514 (2)	0.43812 (9)	0.0175 (2)
H7A	−0.381335	0.098919	0.377488	0.026*
H7B	−0.448752	0.163281	0.480064	0.026*
H7C	−0.224743	0.032488	0.462053	0.026*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.01416 (11)	0.01407 (11)	0.01605 (12)	−0.00108 (10)	0.00637 (8)	−0.00091 (10)
O1	0.0117 (3)	0.0077 (3)	0.0216 (4)	0.0011 (3)	0.0036 (3)	0.0016 (3)
O2	0.0114 (3)	0.0072 (3)	0.0170 (4)	−0.0006 (2)	−0.0009 (3)	−0.0006 (3)
O3	0.0144 (3)	0.0112 (3)	0.0100 (3)	0.0016 (3)	−0.0009 (2)	0.0005 (3)
N1	0.0094 (3)	0.0088 (4)	0.0118 (4)	−0.0009 (3)	0.0007 (3)	0.0011 (3)
N2	0.0087 (3)	0.0068 (3)	0.0133 (4)	−0.0008 (3)	0.0007 (3)	0.0006 (3)
C1	0.0119 (4)	0.0079 (3)	0.0199 (4)	0.0005 (4)	0.0050 (3)	0.0024 (4)
C2	0.0085 (4)	0.0074 (3)	0.0121 (4)	−0.0012 (3)	−0.0009 (3)	0.0003 (3)
C3	0.0086 (3)	0.0077 (3)	0.0104 (4)	−0.0009 (3)	0.0001 (3)	0.0014 (3)
C4	0.0068 (3)	0.0076 (3)	0.0107 (4)	0.0006 (3)	0.0011 (3)	−0.0006 (3)
C5	0.0121 (4)	0.0104 (4)	0.0110 (4)	−0.0013 (3)	0.0021 (3)	−0.0007 (3)
C6	0.0141 (4)	0.0113 (4)	0.0142 (4)	−0.0011 (3)	0.0054 (3)	−0.0003 (3)
C7	0.0147 (5)	0.0183 (5)	0.0194 (5)	−0.0046 (4)	0.0030 (4)	0.0025 (4)

Geometric parameters (Å, º)

S1—C7	1.8037 (13)	C1—H1D	0.9900
S1—C6	1.8114 (11)	C1—H1E	0.9900
O1—C2	1.2310 (13)	C3—C4	1.5415 (15)
O2—C4	1.2598 (13)	C3—C5	1.5417 (15)
O3—C4	1.2546 (13)	C3—H3	1.0000
N1—C1	1.4809 (14)	C5—C6	1.5262 (16)
N1—H11N	0.83 (2)	C5—H5A	0.9900
N1—H12N	0.886 (19)	C5—H5B	0.9900
N1—H13N	0.849 (19)	C6—H6A	0.9900
N2—C2	1.3437 (14)	C6—H6B	0.9900
N2—C3	1.4527 (14)	C7—H7A	0.9800
N2—H2N	0.832 (19)	C7—H7B	0.9800
C1—C2	1.5181 (16)	C7—H7C	0.9800
C7—S1—C6	98.22 (6)	C4—C3—H3	108.8
C1—N1—H11N	107.2 (13)	C5—C3—H3	108.8
C1—N1—H12N	111.5 (12)	O3—C4—O2	125.57 (10)
H11N—N1—H12N	107.1 (19)	O3—C4—C3	117.55 (9)
C1—N1—H13N	110.1 (12)	O2—C4—C3	116.86 (9)
H11N—N1—H13N	107.3 (19)	C6—C5—C3	111.85 (9)
H12N—N1—H13N	113.3 (18)	C6—C5—H5A	109.2
C2—N2—C3	118.29 (9)	C3—C5—H5A	109.2
C2—N2—H2N	115.1 (13)	C6—C5—H5B	109.2
C3—N2—H2N	118.5 (13)	C3—C5—H5B	109.2
N1—C1—C2	109.41 (9)	H5A—C5—H5B	107.9
N1—C1—H1D	109.8	C5—C6—S1	110.86 (8)
C2—C1—H1D	109.8	C5—C6—H6A	109.5
N1—C1—H1E	109.8	S1—C6—H6A	109.5
C2—C1—H1E	109.8	C5—C6—H6B	109.5
H1D—C1—H1E	108.2	S1—C6—H6B	109.5
O1—C2—N2	124.15 (10)	H6A—C6—H6B	108.1
O1—C2—C1	120.47 (9)	S1—C7—H7A	109.5
N2—C2—C1	115.37 (9)	S1—C7—H7B	109.5
N2—C3—C4	110.59 (8)	H7A—C7—H7B	109.5
N2—C3—C5	109.33 (9)	S1—C7—H7C	109.5
C4—C3—C5	110.53 (8)	H7A—C7—H7C	109.5
N2—C3—H3	108.8	H7B—C7—H7C	109.5
C3—N2—C2—O1	−15.40 (16)	C5—C3—C4—O3	93.47 (11)
C3—N2—C2—C1	163.44 (9)	N2—C3—C4—O2	153.99 (9)
N1—C1—C2—O1	−8.46 (15)	C5—C3—C4—O2	−84.80 (11)
N1—C1—C2—N2	172.66 (9)	N2—C3—C5—C6	−176.94 (9)
C2—N2—C3—C4	−62.19 (12)	C4—C3—C5—C6	61.10 (12)
C2—N2—C3—C5	175.89 (9)	C3—C5—C6—S1	177.94 (8)
N2—C3—C4—O3	−27.75 (13)	C7—S1—C6—C5	171.26 (9)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H11N···O3^i	0.83 (2)	2.15 (2)	2.8513 (13)	143.0 (18)
N1—H11N···O1	0.83 (2)	2.15 (2)	2.6619 (13)	120.1 (16)
N1—H12N···O2^ii	0.886 (19)	1.850 (19)	2.7275 (12)	170.7 (18)
N1—H13N···O3^iii	0.849 (19)	1.86 (2)	2.7006 (13)	168 (2)
N2—H2N···O2^iv	0.832 (19)	2.000 (19)	2.8225 (12)	170.0 (18)

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

L-Methionyl-L-glycine (Met-Gly)

Crystal data

C7H14N2O3S	Dx = 1.382 Mg m^−3
Mr = 206.26	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121	Cell parameters from 9827 reflections
a = 5.2521 (3) Å	θ = 3.0–40.2°
b = 11.4126 (7) Å	µ = 0.31 mm^−1
c = 16.5403 (10) Å	T = 90 K
V = 991.43 (10) Å^3	Needle fragment, colourless
Z = 4	0.25 × 0.24 × 0.17 mm
F(000) = 440

Data collection

Bruker Kappa APEXII DUO CCD diffractometer	6231 independent reflections
Radiation source: fine-focus sealed tube	5939 reflections with I > 2σ(I)
TRIUMPH curved graphite monochromator	Rint = 0.030
φ and ω scans	θmax = 40.3°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −8→9
Tmin = 0.872, Tmax = 0.950	k = −20→20
33593 measured reflections	l = −30→30

Refinement

Refinement on F^2	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.023	w = 1/[σ^2(Fo^2) + (0.0356P)^2 + 0.0451P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.061	(Δ/σ)max = 0.001
S = 1.06	Δρmax = 0.44 e Å^−3
6231 reflections	Δρmin = −0.20 e Å^−3
131 parameters	Absolute structure: Flack x determined using 2494 quotients [(I^+)-(I^-)]/[(I^+)+(I^-)] Parsons et al. (2013)
0 restraints	Absolute structure parameter: 0.011 (11)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
S1	0.29353 (4)	0.65791 (2)	0.59184 (2)	0.01687 (4)
O1	0.56607 (10)	0.47315 (6)	0.32954 (3)	0.01617 (10)
O2	−0.07675 (10)	0.65590 (6)	0.16589 (4)	0.01625 (10)
O3	0.24892 (10)	0.71309 (4)	0.08834 (3)	0.01128 (8)
N1	0.29316 (11)	0.32887 (5)	0.42498 (3)	0.00925 (8)
H11N	0.230 (3)	0.2667 (12)	0.4002 (8)	0.014*
H12N	0.280 (3)	0.3155 (11)	0.4782 (8)	0.014*
H13N	0.461 (3)	0.3287 (11)	0.4122 (7)	0.014*
N2	0.21065 (12)	0.55612 (5)	0.27617 (3)	0.01213 (9)
H2N	0.044 (3)	0.5631 (11)	0.2749 (8)	0.015*
C1	0.37117 (14)	0.56727 (6)	0.50511 (4)	0.01293 (10)
H1D	0.471236	0.613218	0.465519	0.016*
H1E	0.475036	0.499402	0.522492	0.016*
C2	0.12412 (13)	0.52445 (6)	0.46605 (4)	0.01108 (9)
H2A	0.028903	0.593014	0.445308	0.013*
H2B	0.017812	0.486494	0.507971	0.013*
C3	0.16563 (12)	0.43738 (5)	0.39633 (3)	0.00966 (9)
H3	−0.003367	0.416245	0.372606	0.012*
C4	0.33345 (12)	0.48982 (6)	0.32997 (4)	0.01035 (9)
C5	0.34421 (13)	0.61524 (6)	0.21120 (4)	0.01259 (10)
H5A	0.459462	0.559260	0.183793	0.015*
H5B	0.448980	0.679543	0.233724	0.015*
C6	0.15608 (12)	0.66476 (6)	0.15042 (3)	0.00962 (9)
C7	0.59992 (18)	0.66260 (8)	0.64043 (6)	0.02365 (16)
H7A	0.662481	0.582565	0.648561	0.035*
H7B	0.584132	0.701884	0.692882	0.035*
H7C	0.719997	0.705915	0.606324	0.035*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
S1	0.01555 (8)	0.01596 (7)	0.01911 (8)	0.00057 (6)	0.00040 (6)	−0.00632 (6)
O1	0.00866 (19)	0.0242 (2)	0.0157 (2)	0.00274 (18)	0.00070 (17)	0.00795 (19)
O2	0.00915 (19)	0.0230 (2)	0.0166 (2)	−0.00048 (18)	0.00041 (16)	0.01047 (19)
O3	0.0129 (2)	0.01408 (18)	0.00689 (15)	−0.00366 (14)	0.00063 (14)	0.00177 (14)
N1	0.00953 (18)	0.01015 (17)	0.00807 (17)	0.00097 (16)	−0.00063 (15)	0.00075 (14)
N2	0.0095 (2)	0.0172 (2)	0.00969 (19)	0.00194 (19)	0.00069 (17)	0.00605 (17)
C1	0.0123 (2)	0.0118 (2)	0.0147 (2)	−0.0001 (2)	0.0012 (2)	−0.00119 (19)
C2	0.0104 (2)	0.0112 (2)	0.0117 (2)	0.00167 (18)	0.00146 (18)	0.00075 (18)
C3	0.0085 (2)	0.0115 (2)	0.0090 (2)	0.00079 (17)	−0.00053 (16)	0.00217 (16)
C4	0.0096 (2)	0.0131 (2)	0.00842 (19)	0.00101 (18)	−0.00038 (17)	0.00254 (17)
C5	0.0094 (2)	0.0181 (3)	0.0103 (2)	0.0009 (2)	0.00068 (18)	0.00519 (19)
C6	0.0102 (2)	0.0109 (2)	0.00774 (19)	−0.00110 (18)	−0.00008 (16)	0.00155 (17)
C7	0.0228 (4)	0.0199 (3)	0.0283 (4)	−0.0025 (3)	−0.0075 (3)	−0.0061 (3)

Geometric parameters (Å, º)

S1—C7	1.7995 (9)	C1—H1D	0.9900
S1—C1	1.8150 (7)	C1—H1E	0.9900
O1—C4	1.2365 (8)	C2—C3	1.5379 (9)
O2—C6	1.2534 (9)	C2—H2A	0.9900
O3—C6	1.2635 (8)	C2—H2B	0.9900
N1—C3	1.4855 (8)	C3—C4	1.5297 (9)
N1—H11N	0.885 (14)	C3—H3	1.0000
N1—H12N	0.896 (13)	C5—C6	1.5186 (9)
N1—H13N	0.907 (14)	C5—H5A	0.9900
N2—C4	1.3342 (8)	C5—H5B	0.9900
N2—C5	1.4499 (9)	C7—H7A	0.9800
N2—H2N	0.879 (15)	C7—H7B	0.9800
C1—C2	1.5296 (10)	C7—H7C	0.9800
C7—S1—C1	99.74 (4)	N1—C3—C2	111.31 (5)
C3—N1—H11N	110.5 (9)	C4—C3—C2	111.53 (5)
C3—N1—H12N	114.9 (8)	N1—C3—H3	108.9
H11N—N1—H12N	106.8 (12)	C4—C3—H3	108.9
C3—N1—H13N	111.5 (8)	C2—C3—H3	108.9
H11N—N1—H13N	105.0 (12)	O1—C4—N2	124.13 (6)
H12N—N1—H13N	107.6 (12)	O1—C4—C3	120.88 (6)
C4—N2—C5	121.62 (6)	N2—C4—C3	114.95 (6)
C4—N2—H2N	123.3 (8)	N2—C5—C6	110.43 (6)
C5—N2—H2N	115.0 (8)	N2—C5—H5A	109.6
C2—C1—S1	108.98 (5)	C6—C5—H5A	109.6
C2—C1—H1D	109.9	N2—C5—H5B	109.6
S1—C1—H1D	109.9	C6—C5—H5B	109.6
C2—C1—H1E	109.9	H5A—C5—H5B	108.1
S1—C1—H1E	109.9	O2—C6—O3	125.28 (6)
H1D—C1—H1E	108.3	O2—C6—C5	118.01 (5)
C1—C2—C3	113.76 (6)	O3—C6—C5	116.70 (6)
C1—C2—H2A	108.8	S1—C7—H7A	109.5
C3—C2—H2A	108.8	S1—C7—H7B	109.5
C1—C2—H2B	108.8	H7A—C7—H7B	109.5
C3—C2—H2B	108.8	S1—C7—H7C	109.5
H2A—C2—H2B	107.7	H7A—C7—H7C	109.5
N1—C3—C4	107.17 (5)	H7B—C7—H7C	109.5
C7—S1—C1—C2	165.35 (5)	C2—C3—C4—O1	93.98 (8)
S1—C1—C2—C3	−174.71 (4)	N1—C3—C4—N2	154.05 (6)
C1—C2—C3—N1	62.23 (7)	C2—C3—C4—N2	−83.89 (7)
C1—C2—C3—C4	−57.41 (7)	C4—N2—C5—C6	169.26 (6)
C5—N2—C4—O1	0.09 (11)	N2—C5—C6—O2	4.52 (9)
C5—N2—C4—C3	177.89 (6)	N2—C5—C6—O3	−176.26 (6)
N1—C3—C4—O1	−28.08 (9)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H11N···O2^i	0.885 (14)	1.854 (14)	2.7290 (8)	169.5 (13)
N1—H11N···O3^i	0.885 (14)	2.593 (15)	3.1465 (8)	121.4 (11)
N1—H12N···O3^ii	0.896 (13)	1.857 (13)	2.7531 (7)	179.6 (14)
N1—H13N···O3^iii	0.907 (14)	2.015 (14)	2.7529 (8)	137.5 (11)
N1—H13N···O1	0.907 (14)	2.211 (13)	2.6940 (8)	112.7 (10)
N2—H2N···O2	0.879 (15)	2.185 (13)	2.6273 (8)	110.6 (10)

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