Supra­molecular architectures in cytosinium 6-chloro­nicotinate monohydrate and 5-bromo-6-methyl­isocytosinium hydrogen sulfate

Amino­pyrimidine derivatives are biologically important as they are components of nucleic acids and drugs. The crystals of two new salts, namely cytosinium 6-chloro­nicotinate monohydrate, C₄H₆N₃O⁺·C₆H₃ClNO₂⁻·H₂O, (I), and 5-bromo-6-methyl­isocytosinium hydrogen sulfate (or 2-amino-5-bromo-4-oxo-6-methyl­pyrimidinium hydrogen sulfate), C₅H₇BrN₃O⁺·HSO₄⁻, (II), have been prepared and characterized by single-crystal X-ray diffraction. The pyrimidine ring of both compounds is protonated at the imine N atom. In hydrated salt (I), the primary R₂²(8) ring motif (supra­molecular heterosynthon) is formed via a pair of N—H...O(carboxyl­ate) hydrogen bonds. The cations, anions and water mol­ecule are hydrogen bonded through N—H...O, N—H...N, O—H...O and C—H...O hydrogen bonds, forming R₂²(8), R₃²(7) and R₅⁵(21) motifs, leading to a hydrogen-bonded supra­molecular sheet structure. The supra­molecular double sheet structure is formed via water–carboxylate O—H...O hydrogen bonds and π–π inter­actions between the anions and the cations. In salt (II), the hydrogen sulfate ions are linked via O—H...O hydrogen bonds to generate zigzag chains. The amino­pyrimidinium cations are embedded between these zigzag chains. Each hydrogen sulfate ion bridges two cations via pairs of N—H...O hydrogen bonds and vice versa, generating two R₂²(8) ring motifs (supra­molecular heterosynthon). The cations also inter­act with one another via halogen–halogen (Br...Br) and halogen–oxygen (Br...O) inter­actions.

Computing details

For both structures, data collection: CrysAlis PRO (Agilent, 2013); cell refinement: CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis PRO (Agilent, 2013). Program(s) used to solve structure: SHELXS2013 (Sheldrick, 2015a) for (I); SHELX2014/7 (Sheldrick, 2015) for (II). Program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b) for (I); SHELX2014/7 (Sheldrick, 2015) for (II). Molecular graphics: ORTEP-3 for Windows (Farrugia, 2012), PLATON (Spek, 2009) and Mercury (Macrae et al., 2008) for (I); PLATON (Spek, 2009), Mercury (Macrae et al., 2008) for (II). Software used to prepare material for publication: PLATON (Spek, 2009) and publCIF (Westrip, 2010) for (I); PLATON (Spek, 2009) for (II).

Cytosinium 6-chloropyridine-3-carboxylate (I)

Crystal data

C4H6N3O^+·C6H3ClNO2^−·H2O	Dx = 1.562 Mg m^−3
Mr = 286.68	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pccn	Cell parameters from 2286 reflections
a = 19.5314 (12) Å	θ = 3.8–29.4°
b = 12.7103 (10) Å	µ = 0.33 mm^−1
c = 9.8189 (5) Å	T = 293 K
V = 2437.5 (3) Å^3	Plate, colorless
Z = 8	0.30 × 0.25 × 0.08 mm
F(000) = 1184

Data collection

Agilent SuperNova Dual Source diffractometer with an Atlas detector	2800 independent reflections
Radiation source: SuperNova (Mo) X-ray Source	1688 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.047
Detector resolution: 10.4933 pixels mm^-1	θmax = 27.5°, θmin = 2.8°
ω scans	h = −23→25
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013)	k = −14→16
Tmin = 0.409, Tmax = 1.000	l = −12→11
10045 measured reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.061	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.184	w = 1/[σ^2(Fo^2) + (0.0845P)^2 + 1.0271P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max < 0.001
2800 reflections	Δρmax = 0.49 e Å^−3
178 parameters	Δρmin = −0.30 e Å^−3

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
Cl1	0.67574 (4)	0.36365 (8)	−0.49716 (9)	0.0525 (3)
O3	0.48180 (11)	0.36704 (18)	0.0450 (2)	0.0467 (6)
O4	0.57869 (11)	0.4109 (2)	0.1506 (2)	0.0508 (7)
C7	0.54367 (15)	0.3756 (2)	−0.2072 (3)	0.0361 (7)
H7	0.4962	0.3726	−0.2010	0.043*
C8	0.58057 (14)	0.3855 (2)	−0.0889 (3)	0.0322 (7)
C9	0.65089 (15)	0.3901 (3)	−0.0985 (3)	0.0406 (8)
H9	0.6774	0.3980	−0.0206	0.049*
C10	0.68162 (16)	0.3828 (3)	−0.2246 (3)	0.0437 (8)
H10	0.7290	0.3847	−0.2340	0.052*
C11	0.63964 (15)	0.3728 (2)	−0.3353 (3)	0.0334 (7)
C12	0.54426 (16)	0.3880 (2)	0.0465 (3)	0.0379 (7)
O2	0.31280 (11)	0.35833 (18)	0.1369 (2)	0.0478 (6)
N1	0.30134 (13)	0.3640 (2)	0.3669 (3)	0.0404 (7)
H1	0.2574	0.3658	0.3609	0.048*
N3	0.40838 (11)	0.36435 (19)	0.2674 (2)	0.0336 (6)
H3	0.4337	0.3643	0.1957	0.040*
N4	0.50634 (12)	0.3757 (2)	0.3939 (3)	0.0397 (7)
H4A	0.5294	0.3787	0.3194	0.048*
H4B	0.5271	0.3779	0.4710	0.048*
N5	0.57245 (12)	0.3700 (2)	−0.3318 (2)	0.0358 (6)
C2	0.33890 (15)	0.3610 (2)	0.2500 (3)	0.0357 (7)
C4	0.43982 (15)	0.3677 (2)	0.3899 (3)	0.0310 (6)
C5	0.39817 (16)	0.3645 (2)	0.5086 (3)	0.0396 (7)
H5	0.4177	0.3627	0.5949	0.047*
C6	0.33059 (16)	0.3641 (2)	0.4930 (3)	0.0396 (8)
H6	0.3027	0.3640	0.5697	0.048*
O1W	0.65468 (14)	0.6049 (2)	0.1498 (3)	0.0567 (8)
H1W	0.639 (2)	0.545 (4)	0.155 (5)	0.085*
H2W	0.649 (3)	0.618 (3)	0.068 (5)	0.085*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0402 (5)	0.0800 (7)	0.0372 (5)	−0.0020 (4)	0.0133 (3)	−0.0096 (4)
O3	0.0303 (12)	0.0814 (17)	0.0284 (12)	−0.0066 (10)	0.0049 (9)	−0.0019 (11)
O4	0.0437 (13)	0.0857 (18)	0.0230 (12)	−0.0129 (12)	−0.0008 (9)	0.0003 (11)
C7	0.0254 (15)	0.0528 (19)	0.0299 (16)	−0.0020 (13)	0.0015 (11)	−0.0001 (14)
C8	0.0276 (14)	0.0457 (18)	0.0233 (15)	−0.0020 (12)	0.0016 (11)	0.0035 (12)
C9	0.0305 (16)	0.059 (2)	0.0322 (18)	−0.0016 (14)	−0.0053 (13)	0.0001 (14)
C10	0.0223 (15)	0.070 (2)	0.0388 (18)	0.0015 (14)	0.0008 (12)	0.0000 (16)
C11	0.0280 (15)	0.0437 (18)	0.0287 (16)	−0.0001 (12)	0.0056 (12)	−0.0014 (13)
C12	0.0363 (17)	0.051 (2)	0.0262 (15)	0.0019 (13)	0.0047 (13)	0.0042 (14)
O2	0.0334 (12)	0.0722 (17)	0.0379 (13)	0.0008 (11)	−0.0085 (9)	−0.0055 (11)
N1	0.0234 (12)	0.0526 (17)	0.0453 (16)	−0.0017 (11)	0.0046 (11)	−0.0009 (13)
N3	0.0243 (12)	0.0520 (16)	0.0244 (13)	−0.0031 (10)	0.0022 (9)	−0.0006 (11)
N4	0.0252 (12)	0.0698 (19)	0.0241 (14)	−0.0017 (11)	−0.0004 (10)	0.0027 (12)
N5	0.0281 (13)	0.0541 (16)	0.0252 (14)	0.0004 (11)	0.0014 (10)	−0.0002 (11)
C2	0.0314 (15)	0.0415 (18)	0.0341 (18)	−0.0012 (13)	−0.0005 (12)	−0.0024 (14)
C4	0.0289 (14)	0.0390 (17)	0.0249 (15)	0.0006 (12)	−0.0003 (11)	0.0030 (12)
C5	0.0341 (16)	0.058 (2)	0.0271 (16)	0.0029 (14)	0.0046 (12)	0.0061 (15)
C6	0.0359 (17)	0.0506 (19)	0.0323 (17)	0.0010 (14)	0.0103 (13)	0.0045 (14)
O1W	0.0455 (14)	0.084 (2)	0.0406 (15)	−0.0126 (13)	−0.0057 (12)	−0.0027 (15)

Geometric parameters (Å, º)

Cl1—C11	1.742 (3)	N1—C6	1.364 (4)
O3—C12	1.249 (4)	N1—H1	0.8600
O4—C12	1.257 (4)	N3—C4	1.351 (3)
C7—N5	1.349 (4)	N3—C2	1.368 (4)
C7—C8	1.373 (4)	N3—H3	0.8600
C7—H7	0.9300	N4—C4	1.304 (4)
C8—C9	1.378 (4)	N4—H4A	0.8600
C8—C12	1.507 (4)	N4—H4B	0.8600
C9—C10	1.379 (4)	C4—C5	1.422 (4)
C9—H9	0.9300	C5—C6	1.329 (4)
C10—C11	1.368 (4)	C5—H5	0.9300
C10—H10	0.9300	C6—H6	0.9300
C11—N5	1.313 (4)	O1W—H1W	0.82 (5)
O2—C2	1.222 (4)	O1W—H2W	0.82 (5)
N1—C2	1.363 (4)
N5—C7—C8	123.6 (3)	C4—N3—C2	124.2 (2)
N5—C7—H7	118.2	C4—N3—H3	117.9
C8—C7—H7	118.2	C2—N3—H3	117.9
C7—C8—C9	118.0 (3)	C4—N4—H4A	120.0
C7—C8—C12	120.1 (3)	C4—N4—H4B	120.0
C9—C8—C12	121.9 (3)	H4A—N4—H4B	120.0
C8—C9—C10	119.5 (3)	C11—N5—C7	116.0 (2)
C8—C9—H9	120.2	O2—C2—N1	122.8 (3)
C10—C9—H9	120.2	O2—C2—N3	121.9 (3)
C11—C10—C9	117.3 (3)	N1—C2—N3	115.3 (3)
C11—C10—H10	121.3	N4—C4—N3	118.8 (3)
C9—C10—H10	121.3	N4—C4—C5	123.2 (3)
N5—C11—C10	125.5 (3)	N3—C4—C5	118.0 (3)
N5—C11—Cl1	115.2 (2)	C6—C5—C4	118.3 (3)
C10—C11—Cl1	119.2 (2)	C6—C5—H5	120.9
O3—C12—O4	125.6 (3)	C4—C5—H5	120.9
O3—C12—C8	116.4 (3)	C5—C6—N1	121.4 (3)
O4—C12—C8	118.0 (3)	C5—C6—H6	119.3
C2—N1—C6	122.6 (3)	N1—C6—H6	119.3
C2—N1—H1	118.7	H1W—O1W—H2W	101 (4)
C6—N1—H1	118.7
N5—C7—C8—C9	0.1 (5)	Cl1—C11—N5—C7	179.2 (2)
N5—C7—C8—C12	−178.2 (3)	C8—C7—N5—C11	1.1 (4)
C7—C8—C9—C10	−1.1 (5)	C6—N1—C2—O2	178.2 (3)
C12—C8—C9—C10	177.1 (3)	C6—N1—C2—N3	−3.6 (4)
C8—C9—C10—C11	0.9 (5)	C4—N3—C2—O2	179.8 (3)
C9—C10—C11—N5	0.4 (5)	C4—N3—C2—N1	1.6 (4)
C9—C10—C11—Cl1	179.8 (3)	C2—N3—C4—N4	−176.8 (3)
C7—C8—C12—O3	9.0 (4)	C2—N3—C4—C5	1.9 (4)
C9—C8—C12—O3	−169.2 (3)	N4—C4—C5—C6	175.1 (3)
C7—C8—C12—O4	−170.9 (3)	N3—C4—C5—C6	−3.6 (4)
C9—C8—C12—O4	10.9 (5)	C4—C5—C6—N1	1.7 (5)
C10—C11—N5—C7	−1.4 (5)	C2—N1—C6—C5	2.0 (5)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1W^i	0.86	2.04	2.896 (4)	171
O1W—H1W···O4	0.82 (5)	2.07 (5)	2.878 (4)	166 (4)
O1W—H2W···O2^ii	0.83 (5)	2.17 (5)	2.923 (4)	152 (6)
N3—H3···O3	0.86	1.75	2.613 (3)	177
N4—H4A···O4	0.86	1.96	2.811 (3)	170
N4—H4B···N5^iii	0.86	2.13	2.988 (4)	174
C6—H6···O2^iv	0.93	2.35	3.138 (4)	142

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

2-amino-5-bromo-4-oxy-6-methylpyrimidinium hydrogensulfate (II)

Crystal data

C5H7BrN3O·HO4S	F(000) = 600
Mr = 302.11	Dx = 2.117 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54184 Å
a = 16.1671 (4) Å	Cell parameters from 2315 reflections
b = 4.8786 (1) Å	θ = 3.6–74.6°
c = 12.0863 (3) Å	µ = 8.13 mm^−1
β = 96.026 (2)°	T = 150 K
V = 948.01 (4) Å^3	Prism, colorless
Z = 4	0.40 × 0.35 × 0.20 mm

Data collection

Agilent SuperNova Dual Source diffractometer with an Atlas detector	1781 independent reflections
Radiation source: SuperNova (Cu) X-ray Source	1710 reflections with I > 2σ(I)
Mirror monochromator	Rint = 0.033
Detector resolution: 10.4933 pixels mm^-1	θmax = 70.1°, θmin = 5.5°
ω scans	h = −19→17
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013)	k = −5→5
Tmin = 0.431, Tmax = 1.000	l = −14→11
3324 measured reflections

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.040	w = 1/[σ^2(Fo^2) + (0.0783P)^2 + 1.515P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.109	(Δ/σ)max = 0.001
S = 1.06	Δρmax = 0.77 e Å^−3
1781 reflections	Δρmin = −1.38 e Å^−3
139 parameters	Extinction correction: SHELXL-2014/7 (Sheldrick, 2015), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0044 (4)

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
Br1	0.96681 (2)	1.14944 (7)	0.63903 (3)	0.0147 (2)
S1	0.60155 (4)	0.23576 (15)	0.71074 (6)	0.0059 (2)
O1	0.85408 (14)	0.7141 (5)	0.73247 (19)	0.0122 (5)
O2	0.69097 (13)	0.2886 (5)	0.72425 (19)	0.0108 (5)
O3	0.55917 (15)	0.3378 (5)	0.6078 (2)	0.0136 (5)
O4	0.56372 (14)	0.3299 (5)	0.80906 (19)	0.0101 (5)
O5	0.59581 (13)	−0.0835 (5)	0.70865 (19)	0.0093 (5)
H5	0.5457	−0.1313	0.7046	0.014*
N1	0.74531 (16)	1.0117 (6)	0.4460 (2)	0.0100 (6)
H1	0.7197	1.0760	0.3836	0.012*
N2	0.63331 (17)	0.7267 (6)	0.4640 (2)	0.0125 (6)
H2A	0.6076	0.7918	0.4017	0.015*
H2B	0.6094	0.5998	0.5014	0.015*
N3	0.74822 (16)	0.7180 (6)	0.5950 (2)	0.0079 (5)
H3	0.7245	0.5830	0.6282	0.010*
C2	0.7071 (2)	0.8186 (7)	0.5010 (3)	0.0083 (6)
C4	0.82565 (19)	0.8106 (7)	0.6444 (3)	0.0083 (6)
C5	0.86285 (18)	1.0192 (7)	0.5796 (2)	0.0074 (6)
C6	0.8233 (2)	1.1151 (7)	0.4828 (3)	0.0097 (6)
C7	0.8550 (2)	1.3261 (7)	0.4091 (3)	0.0124 (7)
H7A	0.8780	1.2359	0.3467	0.019*
H7B	0.8986	1.4339	0.4515	0.019*
H7C	0.8093	1.4473	0.3807	0.019*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Br1	0.0094 (3)	0.0184 (3)	0.0163 (3)	−0.00367 (12)	0.00175 (16)	−0.00200 (13)
S1	0.0049 (4)	0.0042 (4)	0.0089 (4)	−0.0008 (3)	0.0024 (3)	−0.0003 (3)
O1	0.0112 (11)	0.0154 (12)	0.0097 (11)	0.0008 (10)	0.0000 (9)	0.0036 (10)
O2	0.0044 (11)	0.0123 (11)	0.0163 (11)	−0.0016 (9)	0.0038 (8)	0.0009 (10)
O3	0.0133 (12)	0.0136 (12)	0.0131 (12)	−0.0018 (9)	−0.0025 (10)	0.0037 (9)
O4	0.0092 (11)	0.0108 (12)	0.0114 (11)	0.0014 (8)	0.0058 (9)	−0.0042 (8)
O5	0.0076 (10)	0.0041 (11)	0.0168 (12)	−0.0014 (8)	0.0042 (8)	−0.0009 (9)
N1	0.0080 (13)	0.0129 (14)	0.0089 (13)	−0.0007 (11)	0.0000 (9)	0.0040 (11)
N2	0.0100 (13)	0.0181 (15)	0.0088 (13)	−0.0056 (12)	−0.0012 (10)	0.0044 (12)
N3	0.0066 (13)	0.0088 (13)	0.0089 (12)	−0.0018 (10)	0.0032 (10)	0.0027 (11)
C2	0.0092 (15)	0.0089 (15)	0.0077 (15)	0.0009 (12)	0.0047 (12)	−0.0007 (11)
C4	0.0061 (15)	0.0069 (14)	0.0124 (15)	0.0008 (12)	0.0036 (12)	−0.0028 (12)
C5	0.0034 (13)	0.0091 (15)	0.0103 (14)	−0.0009 (11)	0.0029 (10)	−0.0028 (12)
C6	0.0068 (15)	0.0085 (15)	0.0148 (16)	0.0007 (11)	0.0067 (12)	−0.0014 (13)
C7	0.0121 (16)	0.0126 (16)	0.0134 (16)	−0.0022 (13)	0.0060 (12)	0.0019 (13)

Geometric parameters (Å, º)

Br1—C5	1.868 (3)	N2—H2A	0.8800
S1—O3	1.445 (2)	N2—H2B	0.8800
S1—O2	1.461 (2)	N3—C2	1.347 (4)
S1—O4	1.466 (2)	N3—C4	1.404 (4)
S1—O5	1.560 (2)	N3—H3	0.8800
O1—C4	1.210 (4)	C4—C5	1.452 (4)
O5—H5	0.8400	C5—C6	1.357 (5)
N1—C2	1.340 (4)	C6—C7	1.487 (5)
N1—C6	1.387 (4)	C7—H7A	0.9800
N1—H1	0.8800	C7—H7B	0.9800
N2—C2	1.309 (4)	C7—H7C	0.9800
O3—S1—O2	114.20 (14)	N2—C2—N3	121.0 (3)
O3—S1—O4	112.95 (14)	N1—C2—N3	117.5 (3)
O2—S1—O4	110.26 (14)	O1—C4—N3	119.3 (3)
O3—S1—O5	107.93 (13)	O1—C4—C5	127.3 (3)
O2—S1—O5	103.56 (13)	N3—C4—C5	113.4 (3)
O4—S1—O5	107.25 (13)	C6—C5—C4	121.5 (3)
S1—O5—H5	109.5	C6—C5—Br1	122.5 (2)
C2—N1—C6	123.2 (3)	C4—C5—Br1	116.0 (2)
C2—N1—H1	118.4	C5—C6—N1	118.8 (3)
C6—N1—H1	118.4	C5—C6—C7	126.5 (3)
C2—N2—H2A	120.0	N1—C6—C7	114.8 (3)
C2—N2—H2B	120.0	C6—C7—H7A	109.5
H2A—N2—H2B	120.0	C6—C7—H7B	109.5
C2—N3—C4	125.5 (3)	H7A—C7—H7B	109.5
C2—N3—H3	117.3	C6—C7—H7C	109.5
C4—N3—H3	117.3	H7A—C7—H7C	109.5
N2—C2—N1	121.5 (3)	H7B—C7—H7C	109.5
C6—N1—C2—N2	179.7 (3)	O1—C4—C5—Br1	0.7 (4)
C6—N1—C2—N3	−1.6 (5)	N3—C4—C5—Br1	−179.2 (2)
C4—N3—C2—N2	−176.9 (3)	C4—C5—C6—N1	0.5 (5)
C4—N3—C2—N1	4.3 (5)	Br1—C5—C6—N1	−178.5 (2)
C2—N3—C4—O1	175.8 (3)	C4—C5—C6—C7	−179.6 (3)
C2—N3—C4—C5	−4.4 (5)	Br1—C5—C6—C7	1.4 (5)
O1—C4—C5—C6	−178.4 (3)	C2—N1—C6—C5	−0.7 (5)
N3—C4—C5—C6	1.8 (4)	C2—N1—C6—C7	179.4 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O2^i	0.88	2.04	2.900 (3)	165
N2—H2A···O4^i	0.88	2.24	3.002 (4)	145
N2—H2A···O5^ii	0.88	2.53	3.160 (3)	129
N2—H2B···O3	0.88	2.04	2.915 (4)	172
N3—H3···O2	0.88	1.96	2.827 (4)	169
O5—H5···O4^iii	0.84	1.77	2.600 (3)	170

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