L-Prolinium tri­chloro­acetate at 105 K

In the title compound, C₅H₁₀NO₂⁺·C₂Cl₃O₂⁻, the proline mol­ecule exists as a cation with a positively charged amino group and a neutral carboxyl­ic acid group. The tri­chloro­acetic acid mol­ecule is in the anionic state. The 3₁-screw-related proline cations and tri­chloro­acetate anions are linked by N—H...O and O—H...O hydrogen bonds to form molecular columns along the c axis. No head-to-tail hydrogen bonds are observed.

Key indicators

• Single-crystal X-ray study
• T = 105 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.026
• wR factor = 0.069
• Data-to-parameter ratio = 24.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes



REFLT_03
         From the CIF: _diffrn_reflns_theta_max           35.03
         From the CIF: _reflns_number_total               4363
         Count of symmetry unique reflns         2447
         Completeness (_total/calc)            178.30%
         TEST3: Check Friedels for noncentro structure
         Estimate of Friedel pairs measured      1916
         Fraction of Friedel pairs measured     0.783
         Are heavy atom types Z>Si present          yes
          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.

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Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1999); software used to prepare material for publication: SHELXL97.

L-prolinium trichloroacetate

Crystal data

C5H10NO2^+·C2Cl3O2^−	Dx = 1.669 Mg m^−3 Dm = 1.65 Mg m^−3 Dm measured by flotation in a mixture of xylene and bromoform
Mr = 278.51	Mo Kα radiation, λ = 0.71073 Å
Trigonal, P31	Cell parameters from 1024 reflections
Hall symbol: P 31	θ = 3–35°
a = 9.7541 (14) Å	µ = 0.82 mm^−1
c = 10.089 (2) Å	T = 105 K
V = 831.3 (2) Å^3	Prismatic, colourless
Z = 3	0.5 × 0.4 × 0.3 mm
F(000) = 426

Data collection

Bruker SMART diffractometer	4363 independent reflections
Radiation source: fine-focus sealed tube	4258 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.021
Detector resolution: 8 pixels mm^-1	θmax = 35.0°, θmin = 2.4°
ω scans	h = −14→15
Absorption correction: multi-scan (SADABS; Bruker, 1998)	k = −15→15
Tmin = 0.664, Tmax = 0.782	l = −15→16
13374 measured reflections

Refinement

Refinement on F^2	Hydrogen site location: difference Fourier map
Least-squares matrix: full	All H-atom parameters refined
R[F^2 > 2σ(F^2)] = 0.026	w = 1/[σ^2(Fo^2) + (0.041P)^2 + 0.1873P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.069	(Δ/σ)max < 0.001
S = 1.02	Δρmax = 0.45 e Å^−3
4363 reflections	Δρmin = −0.42 e Å^−3
177 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.008 (2)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 1915 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.00 (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
Cl1	0.15562 (4)	0.58351 (4)	0.80263 (4)	0.03181 (8)
Cl2	−0.14731 (4)	0.56751 (4)	0.79662 (4)	0.03248 (8)
Cl3	−0.02231 (6)	0.50100 (4)	0.56123 (3)	0.03624 (10)
N1	0.21536 (11)	0.16603 (11)	0.62088 (9)	0.01506 (14)
O1	0.11683 (13)	0.33330 (12)	0.34074 (9)	0.02341 (17)
O2	0.13140 (13)	0.11106 (11)	0.36345 (9)	0.02372 (17)
O3	0.19102 (12)	0.89718 (10)	0.75413 (9)	0.02275 (17)
O4	0.06676 (13)	0.83180 (11)	0.55830 (9)	0.02325 (17)
C1	0.14132 (13)	0.23136 (12)	0.40733 (10)	0.01616 (16)
C2	0.19069 (13)	0.28623 (12)	0.54964 (10)	0.01583 (16)
C3	0.35348 (17)	0.43601 (14)	0.55455 (13)	0.0242 (2)
C4	0.46725 (15)	0.37208 (17)	0.53572 (13)	0.0265 (2)
C5	0.38786 (15)	0.21247 (15)	0.60752 (15)	0.0244 (2)
C6	0.10354 (13)	0.80177 (12)	0.66771 (11)	0.01622 (16)
C7	0.02752 (13)	0.62085 (12)	0.70449 (11)	0.01681 (17)
H1O	0.111 (3)	0.314 (3)	0.254 (3)	0.046 (7)*
H1N	0.158 (3)	0.080 (3)	0.595 (2)	0.029 (5)*
H2N	0.192 (2)	0.167 (2)	0.704 (2)	0.019 (4)*
H2	0.112 (3)	0.298 (3)	0.588 (2)	0.034 (6)*
H3A	0.364 (3)	0.508 (3)	0.485 (3)	0.037 (6)*
H3B	0.358 (3)	0.480 (3)	0.638 (3)	0.039 (6)*
H4A	0.483 (3)	0.356 (3)	0.444 (3)	0.042 (7)*
H4B	0.565 (3)	0.437 (3)	0.572 (2)	0.036 (6)*
H5A	0.394 (3)	0.130 (3)	0.559 (2)	0.034 (6)*
H5B	0.433 (3)	0.220 (3)	0.703 (3)	0.042 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.02881 (15)	0.02128 (13)	0.0471 (2)	0.01383 (12)	−0.01275 (13)	0.00373 (12)
Cl2	0.02354 (13)	0.02782 (15)	0.04450 (19)	0.01165 (11)	0.01497 (12)	0.01044 (12)
Cl3	0.0649 (3)	0.02013 (13)	0.02403 (13)	0.02154 (15)	−0.00642 (14)	−0.00640 (10)
N1	0.0163 (4)	0.0132 (3)	0.0158 (3)	0.0074 (3)	0.0017 (3)	0.0012 (3)
O1	0.0358 (5)	0.0252 (4)	0.0156 (3)	0.0201 (4)	−0.0036 (3)	−0.0010 (3)
O2	0.0339 (5)	0.0168 (3)	0.0197 (4)	0.0121 (3)	−0.0028 (3)	−0.0036 (3)
O3	0.0321 (4)	0.0146 (3)	0.0155 (3)	0.0071 (3)	−0.0023 (3)	0.0006 (3)
O4	0.0321 (5)	0.0187 (4)	0.0184 (3)	0.0122 (3)	−0.0054 (3)	0.0009 (3)
C1	0.0166 (4)	0.0146 (4)	0.0154 (4)	0.0064 (3)	0.0003 (3)	0.0004 (3)
C2	0.0202 (4)	0.0148 (4)	0.0143 (4)	0.0102 (3)	0.0007 (3)	0.0001 (3)
C3	0.0288 (6)	0.0126 (4)	0.0243 (5)	0.0052 (4)	−0.0067 (4)	−0.0008 (4)
C4	0.0167 (4)	0.0259 (6)	0.0269 (6)	0.0032 (4)	0.0016 (4)	0.0031 (4)
C5	0.0176 (5)	0.0214 (5)	0.0357 (6)	0.0109 (4)	0.0022 (4)	0.0016 (4)
C6	0.0185 (4)	0.0136 (4)	0.0166 (4)	0.0081 (3)	0.0014 (3)	0.0012 (3)
C7	0.0172 (4)	0.0141 (4)	0.0188 (4)	0.0076 (3)	0.0000 (3)	0.0010 (3)

Geometric parameters (Å, º)

Cl1—C7	1.7689 (12)	C1—C2	1.5238 (15)
Cl2—C7	1.7764 (12)	C2—C3	1.5292 (17)
Cl3—C7	1.7674 (11)	C2—H2	0.92 (2)
N1—C2	1.4938 (14)	C3—C4	1.532 (2)
N1—C5	1.5139 (16)	C3—H3A	0.96 (3)
N1—H1N	0.79 (2)	C3—H3B	0.94 (3)
N1—H2N	0.87 (2)	C4—C5	1.5305 (19)
O1—C1	1.3171 (14)	C4—H4A	0.97 (3)
O1—H1O	0.89 (3)	C4—H4B	0.92 (3)
O2—C1	1.2118 (14)	C5—H5A	0.96 (3)
O3—C6	1.2491 (14)	C5—H5B	1.05 (3)
O4—C6	1.2402 (14)	C6—C7	1.5790 (15)
C2—N1—C5	108.27 (9)	C5—C4—C3	104.72 (10)
C2—N1—H1N	111.9 (17)	C5—C4—H4A	109.4 (16)
C5—N1—H1N	112.0 (17)	C3—C4—H4A	112.8 (17)
C2—N1—H2N	107.6 (14)	C5—C4—H4B	109.5 (16)
C5—N1—H2N	110.2 (14)	C3—C4—H4B	113.1 (16)
H1N—N1—H2N	107 (2)	H4A—C4—H4B	107 (2)
C1—O1—H1O	111.1 (18)	N1—C5—C4	105.54 (10)
O2—C1—O1	126.00 (10)	N1—C5—H5A	108.5 (15)
O2—C1—C2	122.85 (10)	C4—C5—H5A	113.3 (14)
O1—C1—C2	111.12 (9)	N1—C5—H5B	107.5 (16)
N1—C2—C1	108.92 (8)	C4—C5—H5B	112.4 (16)
N1—C2—C3	103.68 (9)	H5A—C5—H5B	109 (2)
C1—C2—C3	111.15 (9)	O4—C6—O3	128.01 (11)
N1—C2—H2	111.7 (15)	O4—C6—C7	116.33 (10)
C1—C2—H2	107.6 (15)	O3—C6—C7	115.64 (9)
C3—C2—H2	113.8 (16)	C6—C7—Cl3	111.54 (7)
C2—C3—C4	102.98 (9)	C6—C7—Cl1	112.11 (7)
C2—C3—H3A	110.8 (16)	Cl3—C7—Cl1	108.09 (6)
C4—C3—H3A	112.2 (15)	C6—C7—Cl2	107.21 (7)
C2—C3—H3B	104.8 (16)	Cl3—C7—Cl2	109.14 (6)
C4—C3—H3B	115.0 (17)	Cl1—C7—Cl2	108.68 (6)
H3A—C3—H3B	111 (2)
C5—N1—C2—C1	91.81 (11)	C2—N1—C5—C4	4.64 (13)
C5—N1—C2—C3	−26.62 (11)	C3—C4—C5—N1	19.21 (13)
O2—C1—C2—N1	−2.43 (15)	O4—C6—C7—Cl3	25.75 (13)
O1—C1—C2—N1	179.46 (9)	O3—C6—C7—Cl3	−155.70 (9)
O2—C1—C2—C3	111.19 (13)	O4—C6—C7—Cl1	147.12 (9)
O1—C1—C2—C3	−66.92 (13)	O3—C6—C7—Cl1	−34.32 (13)
N1—C2—C3—C4	37.96 (11)	O4—C6—C7—Cl2	−93.68 (11)
C1—C2—C3—C4	−78.91 (11)	O3—C6—C7—Cl2	84.87 (11)
C2—C3—C4—C5	−35.30 (13)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···O4^i	0.79 (2)	2.15 (2)	2.8987 (14)	159 (2)
O1—H1O···O3^ii	0.89 (3)	1.69 (3)	2.5775 (13)	175 (3)
N1—H2N···O4^iii	0.87 (2)	2.06 (2)	2.9043 (14)	164 (2)

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