L-Methioninium chloride and L-seleno­methioninium chloride at 103 K

The crystal structures of the title compounds, (S)-1-carboxy-3-(methyl­sulfanyl)­propanaminium chloride, C₅H₁₂NO₂S⁺·Cl^-, and (S)-1-carboxy-3-(methyl­selanyl)­propanaminium chloride, C₅H₁₂NO₂Se⁺·Cl^-, are isomorphous. The proton­ated L-methionine and L-seleno­methionine mol­ecules have almost identical conformations and create very similar contacts with the Cl^- anions in the crystal structures of both compounds. The amino acid cations and the Cl^- anions are linked viaN-H...Cl^- and O-H...Cl^- hydrogen bonds.

S1. Comment

L-Methionine (Met) is an essential amino acid, and in human and animal organisms is involved in many very important processes, such as initiation of translation of messenger RNA, transfer of methyl groups and sulfur metabolism. A naturally occurring Se analogue of methionine is L-selenomethionine (SeMet). Although SeMet is toxic, it is also one of the most important nutritional sources of selenium. L-Selenomethionine is extensively used in protein crystallography for solving the phase problem: incorporation of SeMet into proteins allows the use of single- or multi-wavelength anomalous dispersion methods (Hendrickson, 1991; Hendrickson & Ogata, 1997), since, usually, substitution of Met by SeMet does not change the three-dimensional structure of a protein and such labelling is more effective than other methods of protein derivatization.

In this study, the structures of L-methioninium chloride, (I), and L-selenomethioninium chloride, (II), at 103 K are reported (Fig. 1), this being a similar temperature to that used during X-ray data collection on protein crystals. Geometrical data obtained from SeMet may be applied to refinement and/or comparison with the geometry of SeMet incorporated into proteins. The crystal structure of L-methioninium chloride has previously been determined at 295 K (di Blasio et al., 1977), but the structure of L-selenomethioninium chloride has not been reported to date. The structure of DL-selenomethionine is known (Rajeswaran & Parthasarathy, 1984) and is the only Se analogue of Met reported in the Cambridge Structural Database (CSD, November 2003 version; Allen, 2002; Bruno et al., 2002). \sch

The crystal structures of (I) at 103 K (this work) and 295 K (di Blasio et al., 1977), and the structure of (II) at 103 K (this work), are isomorphous. Both (I) and (II) crystallize in space group P2₁2₁2₁ with very similar unit-cell parameters. For the low-temperature structures, the c parameter is slightly different, at 24.2330 (7) and 25.0978 (12) Å for (I) and (II), respectively. Equivalent bonds in both structures have very similar lengths; only the C—Se distances (C4—Se and C5—Se) are longer than the C—S distances (Tables 1 and3).

Not only is the intramolecular geometry of the methioninium and selenomethioninium cations similar, but also the contacts between the cations and Cl⁻ anions present in both structures are identical. The Cl⁻ ions are acceptors in N—H···Cl⁻ and O—H···Cl⁻ hydrogen bonds, which are the most important interactions for structure stability. H atoms from four different amino acid residues surround every Cl⁻ ion. The distances between N atoms and Cl⁻ ions are around 3.2 Å (Tables 2 and 4), and the distance between Cl⁻ and O1 is shorter [3.0239 (10) Å in (I) and 3.0309 (16) Å in (II)]. The arrangement of donors around the Cl⁻ ion may be described as highly distorted from tetrahedral,with the angles in (II), defined by the donors and the Cl⁻ ion, being N···Cl···O1ⁱ 89.09 (4), N···Cl···Nⁱⁱ 96.80 (3), N···Cl···Nⁱⁱⁱ 108.28 (5), Nⁱⁱ···Cl···Nⁱⁱⁱ 105.52 (3), Nⁱⁱ···Cl···O1ⁱ 84.85 (4) and Nⁱⁱⁱ···Cl···O1ⁱ 158.12 (5)° [symmetry codes: (i) x, y − 1, z; (ii) 1 − x, y − 1/2, 1/2 − z; (iii) x − 1, y, z]. The coordination of the Cl⁻ in (I) is very similar and the Nⁱⁱⁱ···Cl···O1ⁱ angle is also strongly distorted [158.61 (3)°].

In the structures of (I) and (II) reported here, both hydrophobic and hydrophilic layers are present (Fig. 2). The hydrophobic layers consist of methionine or selenomethionine side chains, while the hydrophilic layers contain the Cl⁻ ions, amino and carboxylic groups.

Atom O2, in both structures, is involved in short contacts. Firstly, it is an acceptor for a hydrogen bond in which an H atom is donated by atom C2. Secondly, it also participates in an interesting short contact with an N atom, with O2···N(1 − x, y + 1/2, 1/2 − z) 2.9554 (12) Å in (I) and 2.9721 (21) Å in (II). In this type of contact, atom O2 points to the middle of a triangle with corners defined by H atoms from amino groups. O2···H distances are in the range 2.6–3.0 Å and O2···H—N angles are in the range 85–105°. An interaction of this type is not very common: in the CSD (November 2003 version), only ten crystal structures have contacts between an O atom and protonated amino groups with geometries similar to those reported here for (I) and (II).

Rajeswaran & Parthasarathy (1984) noticed that the conformations of methionine and selenomethionine are almost identical and there should be no conformational reason for selecting SeMet over Met in proteins. The conformations of protonated SeMet and Met molecules, in the reported structures of (I) and (II), are also very similar (Tables 1 and 3). From the point of view of conformational flexibility, SeMet incorporated into a protein should behave similarly to Met. The larger size of Se compared with S is probably the most important factor that may influence the interactions and conformations of amino acids in a labelled protein. In order to compare the conformation of the selenomethionine side chain in (II) with the conformations of SeMet in protein molecules, the Protein Data Bank (PDB, August 2004; Berman et al., 2000) was searched. Only SeMet residues having one well defined conformation and derived from structures refined with resolution higher than 1.4 Å were taken into account. Overall, 89 residues were analyzed. The results are presented in Fig. 3. Surprisingly, torsion angles similar to those reported in Table 3 are rarely (3 of 89) observed in protein structures. This may be related to the packing observed in the present structure. Also, in proteins, the conformation of a residue is restrained by covalent bonds in the polypeptide chain. For the C1—C2—C3—C4 and N1—C2—C3—C4 angles, values close to 60 and 180°, or 180 and −60°, respectively, are mostly observed. In the case of the angles C2—C3—C4—Se and C3—C4—Se—C5, the conformational flexibility is higher, but combinations of values close to −60, 60 and 180° occur most often.

S2. Experimental

L-Selenomethionine hydrochloride, (II), was crystallized at room temperature by slow evaporation from an aqueous solution of L-selenomethionine (25 mg ml⁻¹) and 0.1M HCl in a 1:1 ratio. The same procedure was used to crystallize L-methionine hydrochloride, (I), but the concentration of L-Met was 50 mg ml⁻¹. Both L-Met and L-SeMet were purchased from Sigma. Crystals were needle-shaped and were cut to a smaller size for data collection. The absolute structures of both compounds were determined unambiguously by successful refinement of the Flack parameter (Flack, 1983) and the subsequent observation that the error in the Flack parameter was small, specifically 0.05 in the case of (I) and 0.007 in the case of (II).

S3. Refinement

All H atoms in (I) and most of those in (II) were located in the difference Fourier map and refined freely. The methyl and carboxylic acid H atoms of (II) were placed in geometric positions and treated as riding, with C—H = 0.96 and O—H = 0.82 Å, and with U_iso(H) = 1.5U_eq(C,O). Please check added text.

Computing details

For both compounds, data collection: HKL-2000 (Otwinowski & Minor, 1997); cell refinement: HKL-2000; data reduction: HKL-2000; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997) and HKL-2000; molecular graphics: ORTEPIII (Burnett & Johnson, 1996), ORTEP-3 (Farrugia, 1997) and HKL-2000; software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. The molecular structures of (a) (I) and (b) (II), with the atom-numbering schemes. Displacement ellipsoids are drawn at the 50% probability level and H atoms are drawn as small spheres of arbitrary radii.
	Fig. 2. A stereoview of the crystal packing of (II). Cl^− ions and Se atoms are shown as the largest spheres. H atoms have been omitted. Hydrogen bonds are indicated by single dashed lines, and short contacts between atom O2 and N atoms are indicated by double dashed lines.
	Fig. 3. The SeMet torsion angles reported in a subset of the PDB. (a) C1—C2—C3—C4 versus. N—C2—C3—C4. (b) C2—C3—C4—Se versus. C3—C4—Se—C5. Angles derived from protein structures are marked as open diamonds. The solid diamond represents the dihedral angles describing the conformation of selenomethionine in (II).

(I) (S)-1-Carboxy-3-(methylsulfanyl)propanaminium chloride

Crystal data

C5H12NO2S^+·Cl^−	F(000) = 392
Mr = 185.67	Dx = 1.374 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 9199 reflections
a = 5.2740 (1) Å	θ = 3.0–27.5°
b = 7.0220 (2) Å	µ = 0.61 mm^−1
c = 24.2330 (7) Å	T = 103 K
V = 897.45 (4) Å^3	Prism, colourless
Z = 4	0.20 × 0.05 × 0.05 mm

Data collection

Rigaku R-AXIS RAPID diffractometer	2058 independent reflections
Radiation source: fine-focus sealed tube	2009 reflections with I > −3σ(I)
Graphite monochromator	Rint = 0.029
Detector resolution: 10.00 pixels mm^-1	θmax = 27.5°, θmin = 3.0°
ω scan with χ offset	h = −6→6
Absorption correction: multi-scan (Software?; Otwinowski et al., 2003)	k = −8→9
Tmin = 0.932, Tmax = 0.970	l = −26→31
9199 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.019	All H-atom parameters refined
wR(F^2) = 0.050	w = 1/[σ^2(Fo^2) + (0.0266P)^2 + 0.0878P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
2058 reflections	Δρmax = 0.25 e Å^−3
140 parameters	Δρmin = −0.20 e Å^−3
0 restraints	Absolute structure: Flack (1983), with how many Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.01 (5)

Special details

Experimental. During data processing, Bijvoet pairs were scaled separately.

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
Cl	0.21708 (5)	0.42706 (4)	0.185389 (10)	0.01872 (8)
S	0.72352 (6)	0.57178 (4)	0.012965 (10)	0.01995 (8)
O1	0.54662 (19)	1.11990 (13)	0.13534 (4)	0.0275 (2)
O2	0.35613 (15)	0.93707 (12)	0.19910 (3)	0.01988 (17)
N	0.73304 (19)	0.68603 (13)	0.20450 (4)	0.01713 (19)
C1	0.5318 (2)	0.97109 (16)	0.16865 (5)	0.0170 (2)
C2	0.7683 (2)	0.84908 (15)	0.16576 (4)	0.0160 (2)
C3	0.8382 (2)	0.78231 (16)	0.10745 (4)	0.0163 (2)
C4	0.6411 (2)	0.65166 (18)	0.08158 (4)	0.0194 (2)
C5	0.9830 (3)	0.4133 (2)	0.02809 (6)	0.0306 (3)
H1N1	0.588 (3)	0.616 (2)	0.1977 (7)	0.038 (4)*
H1	0.435 (4)	1.192 (3)	0.1449 (8)	0.055 (6)*
H1C3	0.475 (3)	0.722 (2)	0.0769 (6)	0.031 (4)*
H1C4	0.862 (3)	0.893 (2)	0.0848 (6)	0.020 (3)*
H1C5	1.012 (3)	0.343 (2)	−0.0039 (7)	0.037 (4)*
H2N1	0.860 (3)	0.603 (2)	0.2012 (6)	0.023 (4)*
H2C3	1.003 (3)	0.7131 (19)	0.1085 (6)	0.022 (3)*
H2C4	0.610 (3)	0.535 (2)	0.1043 (6)	0.023 (3)*
H2C5	0.949 (4)	0.328 (3)	0.0550 (8)	0.049 (5)*
H3N1	0.735 (3)	0.731 (2)	0.2407 (6)	0.029 (4)*
H3C5	1.134 (4)	0.479 (3)	0.0389 (7)	0.043 (5)*
H1C2	0.909 (3)	0.9242 (18)	0.1790 (5)	0.018 (3)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl	0.01828 (13)	0.01879 (13)	0.01908 (12)	0.00435 (11)	0.00143 (9)	0.00149 (9)
S	0.02143 (15)	0.02275 (14)	0.01566 (13)	0.00009 (13)	0.00003 (10)	−0.00360 (9)
O1	0.0318 (5)	0.0209 (5)	0.0297 (5)	0.0102 (4)	0.0116 (4)	0.0065 (4)
O2	0.0162 (4)	0.0214 (4)	0.0221 (4)	0.0017 (3)	0.0024 (3)	−0.0003 (3)
N	0.0171 (5)	0.0194 (5)	0.0149 (4)	0.0033 (4)	0.0003 (4)	0.0004 (3)
C1	0.0188 (5)	0.0177 (5)	0.0146 (5)	0.0007 (4)	−0.0012 (4)	−0.0028 (4)
C2	0.0146 (5)	0.0176 (5)	0.0159 (4)	0.0000 (5)	0.0006 (4)	−0.0006 (4)
C3	0.0154 (5)	0.0183 (5)	0.0153 (5)	0.0016 (4)	0.0023 (4)	−0.0012 (4)
C4	0.0177 (6)	0.0244 (5)	0.0160 (5)	−0.0014 (5)	0.0023 (4)	−0.0018 (4)
C5	0.0269 (7)	0.0294 (7)	0.0354 (7)	0.0078 (7)	−0.0030 (6)	−0.0103 (6)

Geometric parameters (Å, º)

S—C5	1.8013 (14)	C2—C3	1.5338 (14)
S—C4	1.8078 (11)	C2—H1C2	0.965 (14)
O1—C1	1.3228 (14)	C3—C4	1.5217 (17)
O1—H1	0.81 (2)	C3—H1C4	0.960 (14)
O2—C1	1.2084 (14)	C3—H2C3	0.994 (15)
N—C2	1.4922 (14)	C4—H1C3	1.011 (17)
N—H1N1	0.924 (18)	C4—H2C4	1.000 (15)
N—H2N1	0.890 (16)	C5—H1C5	0.930 (16)
N—H3N1	0.932 (14)	C5—H2C5	0.91 (2)
C1—C2	1.5147 (16)	C5—H3C5	0.956 (19)
C5—S—C4	100.79 (6)	C4—C3—H1C4	110.1 (8)
C1—O1—H1	106.0 (14)	C2—C3—H1C4	108.0 (8)
C2—N—H1N1	113.6 (10)	C4—C3—H2C3	108.1 (8)
C2—N—H2N1	110.6 (10)	C2—C3—H2C3	109.7 (8)
H1N1—N—H2N1	105.0 (13)	H1C4—C3—H2C3	107.2 (12)
C2—N—H3N1	109.2 (9)	C3—C4—S	113.68 (8)
H1N1—N—H3N1	110.8 (14)	C3—C4—H1C3	110.0 (8)
H2N1—N—H3N1	107.5 (13)	S—C4—H1C3	104.8 (8)
O2—C1—O1	125.03 (11)	C3—C4—H2C4	112.3 (8)
O2—C1—C2	123.22 (10)	S—C4—H2C4	107.0 (8)
O1—C1—C2	111.72 (9)	H1C3—C4—H2C4	108.6 (12)
N—C2—C1	107.59 (9)	S—C5—H1C5	106.4 (10)
N—C2—C3	112.02 (9)	S—C5—H2C5	114.0 (13)
C1—C2—C3	114.41 (9)	H1C5—C5—H2C5	106.4 (13)
N—C2—H1C2	107.8 (8)	S—C5—H3C5	112.8 (11)
C1—C2—H1C2	107.9 (8)	H1C5—C5—H3C5	110.2 (14)
C3—C2—H1C2	106.8 (8)	H2C5—C5—H3C5	106.9 (15)
C4—C3—C2	113.56 (9)
O2—C1—C2—N	1.99 (15)	N—C2—C3—C4	58.93 (13)
O1—C1—C2—N	−179.94 (9)	C1—C2—C3—C4	−63.86 (12)
O2—C1—C2—C3	127.14 (12)	C2—C3—C4—S	−179.73 (8)
O1—C1—C2—C3	−54.78 (13)	C5—S—C4—C3	70.14 (10)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N—H1N1···Cl	0.924 (18)	2.383 (19)	3.3054 (10)	176.7 (15)
N—H2N1···Cl^i	0.890 (16)	2.286 (16)	3.1683 (10)	171.1 (13)
N—H3N1···Cl^ii	0.932 (14)	2.273 (15)	3.1709 (10)	161.5 (13)
O1—H1···Cl^iii	0.81 (2)	2.24 (2)	3.0239 (10)	164 (2)
C2—H1C2···O2^i	0.965 (14)	2.410 (14)	3.2627 (14)	147.1 (10)

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

(II) (S)-1-Carboxy-3-(methylselanyl)propanaminium chloride

Crystal data

C5H12NO2Se^+·Cl^−	F(000) = 464
Mr = 232.57	Dx = 1.663 Mg m^−3
Orthorhombic, P212121	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2ab	Cell parameters from 18743 reflections
a = 5.2370 (5) Å	θ = 3.0–31.5°
b = 7.0660 (3) Å	µ = 4.28 mm^−1
c = 25.0960 (12) Å	T = 103 K
V = 928.67 (11) Å^3	Prism, colourless
Z = 4	0.40 × 0.10 × 0.10 mm

Data collection

Rigaku R-AXIS RAPID diffractometer	3082 independent reflections
Radiation source: fine-focus sealed tube	2934 reflections with I > −3σ(I)
Graphite monochromator	Rint = 0.060
Detector resolution: 10.00 pixels mm^-1	θmax = 31.5°, θmin = 3.0°
ω scan with χ offset	h = −7→7
Absorption correction: multi-scan (Software?; Otwinowski et al., 2003)	k = −9→10
Tmin = 0.592, Tmax = 0.652	l = −36→36
18743 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.026	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.069	w = 1/[σ^2(Fo^2) + (0.0322P)^2 + 0.0408P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.002
3082 reflections	Δρmax = 0.89 e Å^−3
125 parameters	Δρmin = −0.87 e Å^−3
0 restraints	Absolute structure: Flack (1983), with how many Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.000 (7)

Special details

Experimental. During data processing, Bijvoet pairs were scaled separately.

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
Se	0.71402 (4)	0.57507 (3)	0.017152 (7)	0.02378 (7)
Cl	0.21581 (8)	0.44426 (6)	0.188426 (17)	0.01971 (9)
O1	0.5460 (3)	1.1378 (2)	0.13950 (6)	0.0294 (3)
H1	0.4310	1.2125	0.1465	0.044*
O2	0.3523 (2)	0.9557 (2)	0.20089 (5)	0.0205 (3)
N	0.7315 (3)	0.7051 (2)	0.20536 (6)	0.0186 (3)
C1	0.5298 (3)	0.9897 (3)	0.17127 (7)	0.0181 (3)
C2	0.7659 (3)	0.8655 (3)	0.16786 (7)	0.0177 (3)
C3	0.8299 (3)	0.7981 (3)	0.11150 (7)	0.0181 (3)
C4	0.6225 (4)	0.6758 (3)	0.08678 (7)	0.0209 (3)
C5	0.9736 (5)	0.3972 (4)	0.04151 (10)	0.0360 (5)
H5A	1.0436	0.3311	0.0114	0.054*
H5B	0.8978	0.3079	0.0656	0.054*
H5C	1.1071	0.4650	0.0595	0.054*
H1C3	0.852 (4)	0.902 (4)	0.0899 (9)	0.015 (5)*
H1C4	0.481 (6)	0.746 (4)	0.0792 (10)	0.034 (7)*
H2N	0.855 (5)	0.613 (4)	0.2032 (11)	0.028 (6)*
H2C3	0.977 (5)	0.726 (4)	0.1119 (9)	0.024 (6)*
H2C4	0.586 (5)	0.571 (4)	0.1072 (10)	0.025 (6)*
H3N	0.751 (5)	0.751 (5)	0.2421 (11)	0.037 (7)*
H1C2	0.919 (5)	0.939 (4)	0.1832 (11)	0.031 (7)*
H1N	0.605 (7)	0.654 (5)	0.1965 (12)	0.047 (9)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Se	0.02651 (10)	0.02612 (12)	0.01871 (9)	−0.00204 (7)	0.00173 (6)	−0.00497 (7)
Cl	0.01778 (15)	0.0197 (2)	0.02165 (18)	0.00465 (16)	0.00117 (13)	0.00137 (14)
O1	0.0337 (7)	0.0209 (8)	0.0335 (8)	0.0107 (6)	0.0142 (6)	0.0069 (6)
O2	0.0149 (5)	0.0216 (7)	0.0249 (6)	0.0018 (4)	0.0031 (4)	0.0000 (5)
N	0.0159 (6)	0.0213 (8)	0.0187 (6)	0.0037 (6)	−0.0003 (5)	−0.0003 (5)
C1	0.0170 (7)	0.0193 (9)	0.0180 (7)	0.0021 (6)	0.0004 (6)	−0.0028 (6)
C2	0.0145 (7)	0.0195 (8)	0.0190 (7)	0.0014 (6)	0.0011 (5)	−0.0009 (6)
C3	0.0158 (7)	0.0210 (9)	0.0175 (7)	0.0021 (6)	0.0028 (5)	−0.0007 (6)
C4	0.0193 (7)	0.0260 (10)	0.0174 (8)	−0.0022 (6)	0.0015 (6)	−0.0027 (7)
C5	0.0343 (10)	0.0306 (13)	0.0432 (13)	0.0058 (9)	−0.0024 (9)	−0.0104 (10)

Geometric parameters (Å, º)

Se—C4	1.9467 (18)	C2—C3	1.530 (2)
Se—C5	1.950 (2)	C2—H1C2	1.03 (3)
O1—C1	1.319 (2)	C3—C4	1.520 (3)
O1—H1	0.8200	C3—H1C3	0.92 (2)
O2—C1	1.214 (2)	C3—H2C3	0.92 (3)
N—C2	1.484 (2)	C4—H1C4	0.91 (3)
N—H2N	0.92 (3)	C4—H2C4	0.92 (3)
N—H3N	0.98 (3)	C5—H5A	0.9600
N—H1N	0.79 (3)	C5—H5B	0.9600
C1—C2	1.518 (2)	C5—H5C	0.9600
C4—Se—C5	97.24 (9)	C4—C3—H1C3	107.6 (14)
C1—O1—H1	109.5	C2—C3—H1C3	108.8 (14)
C2—N—H2N	114.6 (18)	C4—C3—H2C3	106.6 (17)
C2—N—H3N	109.4 (19)	C2—C3—H2C3	110.1 (14)
H2N—N—H3N	102 (2)	H1C3—C3—H2C3	110 (2)
C2—N—H1N	106 (2)	C3—C4—Se	113.47 (12)
H2N—N—H1N	105 (3)	C3—C4—H1C4	110.8 (18)
H3N—N—H1N	120 (3)	Se—C4—H1C4	102.2 (16)
O2—C1—O1	125.20 (17)	C3—C4—H2C4	112.2 (16)
O2—C1—C2	122.94 (17)	Se—C4—H2C4	105.0 (17)
O1—C1—C2	111.84 (15)	H1C4—C4—H2C4	113 (2)
N—C2—C1	107.88 (13)	Se—C5—H5A	109.5
N—C2—C3	112.01 (15)	Se—C5—H5B	109.5
C1—C2—C3	114.23 (14)	H5A—C5—H5B	109.5
N—C2—H1C2	104.0 (16)	Se—C5—H5C	109.5
C1—C2—H1C2	108.9 (16)	H5A—C5—H5C	109.5
C3—C2—H1C2	109.4 (15)	H5B—C5—H5C	109.5
C4—C3—C2	113.45 (14)
O2—C1—C2—N	0.7 (2)	N—C2—C3—C4	61.1 (2)
O1—C1—C2—N	179.19 (16)	C1—C2—C3—C4	−61.9 (2)
O2—C1—C2—C3	125.94 (19)	C2—C3—C4—Se	−175.86 (13)
O1—C1—C2—C3	−55.6 (2)	C5—Se—C4—C3	70.09 (16)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N—H1N···Cl	0.79 (3)	2.53 (3)	3.2974 (17)	166 (3)
N—H2N···Cl^i	0.92 (3)	2.26 (3)	3.1638 (16)	166 (2)
N—H3N···Cl^ii	0.98 (3)	2.22 (3)	3.1681 (17)	161 (3)
O1—H1···Cl^iii	0.82	2.25	3.0309 (16)	160
C2—H1C2···O2^i	1.03 (3)	2.32 (3)	3.244 (2)	149 (2)

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