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In catena-poly[[[diaqua­nickel(II)]-di-μ-glycine] dibromide], {[Ni(C2H5NO2)2(H2O)2]Br2}n, (I), the Ni atom is located on an inversion centre. In catena-poly[[[tetra­aqua­magnesium(II)]-μ-glycine] dichloride], {[Mg(C2H5NO2)(H2O)4]Cl2}n, (II), the Mg atom and the non-H atoms of the glycine mol­ecule are located on a mirror plane. All other atoms are located on general positions. The atomic arrangements of both compounds are characterized by [MO6] octa­hedra (M = Ni or Mg) connected by glycine mol­ecules, with the halogenide ions in the inter­stices. In (I), four of the coordinating O atoms are from glycine and two are from water mol­ecules, building layers of octa­hedra and organic mol­ecules. In (II), two of the coordinating O atoms are from glycine and four are from water mol­ecules. The octa­hedra and organic mol­ecules form chains.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270105023619/jz1726sup1.cif
Contains datablocks global, I, II

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270105023619/jz1726Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270105023619/jz1726IIsup3.hkl
Contains datablock II

CCDC references: 285641; 285642

Comment top

For glycine complexes of divalent metal halogenides, 15 structurally characterized compounds are known, which crystallize in 13 different structural types (Table 1). In the course of our studies of compounds of glycine and inorganic salts, we have found two new examples, namely bis(glycine)nickel(II) dibromide dihydrate, (I), and glycine magnesium(II) dichloride tetrahydrate, (II).

The main features of both structures are the coordination polyhedra of the metal cations. These are slightly distorted octahedra, in which all ligands are O atoms. In compound (I), the NiII atom is located on a centre of symmetry. Four of the ligand atoms (O1, O2 and their equivalents) belong to the carboxylate groups of the glycine molecules, and the remaining two to water molecules. The Ni—O distances range from 2.033 (2) to 2.086 (2) Å, with the shortest to the water molecules. In compound (II), the octahedra display mirror symmetry, and the ligands are four O atoms from water molecules and two carboxylate O atoms (O1 and O2). The Mg—O distances range from 2.016 (1) to 2.062 (1) Å, but here those to the water molecules are the longest. All these distances are in good agreement with usual values for Mg—O and Ni—O ionic bonds (Shannon, 1976). The observed coordination of metal cations solely with oxygen is not common to all the glycine complexes in Table 1; the halogen atoms can also form part of the coordination sphere, as in glycine manganese(II) dichloride dihydrate (Clegg et al., 1987), where two adjacent vertices of the strongly distorted octahedral [MnO4Cl2] unit are Cl atoms.

In both compounds, the glycine molecules exist in the zwitterionic form, NH3+CH2COO, which is normal for compounds of amino acids with inorganic salts. However, there are also many examples in the literature of glycinium or glycinate compounds, e.g. lithium glycinate (Müller et al., 1994) or glycinium chloride (Di Blasio et al., 1977). In compound (I), the glycine ligands are nearly planar, the O1—C1—C2—N torsion angle being −171.03 (1)°. Within the carboxylate groups, both C—O distances are similar [O1—C1 1.251 (3) Å and O2—C1 1.256 (3) Å], which is an expected consequence of delocalization of the electrons in the carboxlate group. The geometry of the glycine molecules in compound (II) is unusual. The molecules (atoms O1, O2, C1, C2, N) are located in a mirror plane. Although stereochemically possible, this symmetry seems to occur very rarely (other amino acid molecules cannot have symmetries other than 1). To the best of our knowledge, this is the first example of symmetry m for a glycine molecule (zwitterion) in a glycine complex of an inorganic salt. Since all non-H atoms lie in the same plane, the O1—C1—C2—N torsion angle is 180°. Even the terminal H atoms of the amino group match this symmetry well. A refinement in the corresponding non-centrosymmetric space group resulted in the same positions, but with very large displacement parameters. Also, a check of this lower symmetry structure with the programme PLATON (Spek, 2003) indicated a 100% probability of the higher symmetry, i.e. Pnma. The C—O distances in the carboxylate groups are 1.242 (1) (O1—C1) and 1.247 (1) Å (O2—C1).

The major structural difference of the two compounds correlates with the different stoichiometries. In compound (I), the ratio of organic molecules to cations is 2:1, and in compound (II) it is 1:1. Since in both compounds the glycine molecules act as bridging ligands, the connectivity of the octahedra via glycine molecules follows the stoichiometry: each octahedron in compound (I) is connected to four adjacent octahedra, and each in compound (II) to two. Consequently, this results in the formation of infinte layers in (I) and of infinite chains in (II). These ratios are also expressed in the degree of hydration, since the remaining apices of the octahedra are O atoms of water molecules. Neither structure contains non-coordinated water molecules. The [Ni(H2O)2(C2H5NO2)2] layers in (I) are oriented parallel to (100), with the glycine molecules essentially perpendicular to the layers and the amino groups facing away from the layers (Figs. 3 and 4). The [Mg(H2O)4(C2H5NO2)] chains in (II) are parallel to [100]. The glycine molecules are oriented nearly perpendicular to the polyhedra chain axis, alternating up and down in the [001] direction, thus giving the chains a zigzag appearance. The symmetry of the chains is 2/m, with the chain axis lying in the mirror plane (Fig. 5). Note that the terms `layer' and `chain' refer to the connectivity resulting from strong interactions, i.e. ionic or covalent bonds.

In both structures, the halogenide ions are located in the interstices between the glycine molecules. In compound (I), each Br anion accepts three hydrogen bonds from amino groups and one from a water molecule. One bond, namely N—H1N···Br, is an inter-layer bond, while the three other bonds exist within the layer. In addition, there is another intra-layer hydrogen bond, namely O1W—H2W···O1. In compound (II), the Cl anions are located in the interstices between the chains and each anion accepts five hydrogen bonds, four from water molecules and one from an amino group. All four water molecules that act as donors are part of different octahedra. Details of the hydrogen bonds are given in Tables 2 and 3.

The 17 known glycine complexes of divalent metal halogenides are summarized in Table 1. An examination of the unit-cell parameters and symmetries of these compounds indicates that most of the structures differ from each other. The only group of isostructural compounds are the bis(glycine) MII dibromide dihydrates, [MIIBr2(C2H5NO2)2]·2H2O (MII = Ni, Co, Mn or Mg). Compound (I) belongs to this group. For the manganese compound (Głowiak & Ciunik, 1978), no H-atom positions were determined, and thus no definitive comparison with the hydrogen-bonding systems in compound (I) can be made. (The authors mention only three hydrogen bonds which are in agreement with the bonds of the title compounds, but no information about the remaining two hydrogen bonds is given.)

It is interesting to note a structural similarity between compound (I), [NiBr2(C2H5NO2)2]·2H2O, and bis(glycine) cobalt dichloride dihydrate, [CoCl2(C2H5NO2)2]·2H2O (Stenzel & Fleck, 2004). Both compounds possess a glycine–metal ratio of 2:1. In both structures the coordination polyhedra and their connection via glycine molecules, as well as the location and intra-layer bonding of the halogenide ions, are nearly identical. When examining diagrams of both structures viewed along the monoclinic axis, they appear to be identical (Fig. 3). However, in the bromide compound, the [Ni(H2O)2(C2H5NO2)2] layers are mutually shifted by 1/2 along the c axis compared with the [Co(H2O)2(C2H5NO2)2] layers of the chloride compound. This can be seen in Fig. 3 when comparing the orientation of the octahedra (note the positions of the apical water molecules: they face alternately `left' and `right'. A view of one layer is given in Fig. 4. This structural relation is also expressed in the unit-cell parameters: the lengths of the b and c axes are similar (see Table 1), as are the distances between the layers (a × sin β), and, consequently, the unit-cell volumes V [a × sin β = 10.970 (Br) or 10.564 Å (Cl), and V = 577.9 (2) Å3 (Br) or 559.4 (2) Å3 (Cl)].

In contrast with the large number (more than 30%) of non-centrosymmetric crystals among structurally characterized glycine compounds [Cambridge Structural Database (Version?; Allen, 2002) and the present compounds], only three out of 17 glycine metal halogenides crystallize non-centrosymmetrically. Groups of spherical symmetry, such as halogenide anions, apparently promote the formation of centrosymmetric crystals. A paper reviewing these structures and discussing the correlation between composition and symmetry of compounds of glycine with inorganic compounds is in preparation (Fleck, unpublished).

Experimental top

Aqueous solutions of glycine and NiBr2 in the molar ratio 1:0.83 for (I), and of glycine and MgCl2 in the molar ratio 1:0.71 for (II), were slowly evaporated at a temperature of approximately 295 K. Over a period of several weeks, small green tabular crystals up to 0.2 mm of compound (I), and colourless elongated crystals up to 0.3 mm of compound (II), were formed.

Computing details top

For both compounds, data collection: COLLECT (Bruker Nonius, 2003); cell refinement: HKL SCALEPACK (Otwinowski & Minor 1997); data reduction: HKL DENZO (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Version 2.1; Bergerhoff et al., 1996); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The connectivity in compound (I) (ORTEP-3; Farrugia, 1997), shown with displacement ellipsoids at the 50% probability level. [Symmetry codes: (i) −x, y + 1/2, 1/2 − z; (ii) −x, −y, −z; (iii) x, 1/2 − y, z + 1/2.]
[Figure 2] Fig. 2. The connectivity in compound (II) (ORTEP-3; Farrugia, 1997), shown with displacement ellipsoids at the 50% probability level. [Symmetry codes: (i) x, 1/2 − y, z; (ii) x + 1/2, y, 1/2 − z.]
[Figure 3] Fig. 3. A packing diagram (DIAMOND; Bergerhoff et al., 1996) for bis(glycine) nickel(II) dibromide dihydrate, [NiBr2(C2H5NO2)2]·2H2O (left), compared with bis(glycine) cobalt dichloride dihydrate, [CoCl2(C2H5NO2)2]·2H2O (right). Both structures are viewed along [010]. The layers are oriented vertically. For the purposes of comparison, the unit cell of the bromide structure is superimposed on the chloride structure (grey lines). To observe the difference between the two compounds notice the orientation of the octahedra.
[Figure 4] Fig. 4. A view (DIAMOND; Bergerhoff et al., 1996) of one layer in bis(glycine) nickel(II) dibromide dihydrate, [NiBr2(C2H5NO2)2]·2H2O, parallel to (100).
[Figure 5] Fig. 5. A packing diagram (DIAMOND; Bergerhoff et al., 1996) for glycine magnesium(II) dichloride tetrahydrate, [MgCl2(C2H5NO2)]·4H2O, viewed along [001]. The chains are oriented horizontally, with the glycine molecules facing away from and towards the viewer.
(I) catena-poly[[[diaquanickel(II)]-di-µ-glycine] dibromide] top
Crystal data top
[NiBr2(C2H5NO2)2(H2O)2]Dx = 2.326 Mg m3
Mr = 404.70Melting point: not determined K
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 11.805 (2) ÅCell parameters from 1569 reflections
b = 6.021 (1) Åθ = 4.1–30.0°
c = 8.749 (2) ŵ = 8.60 mm1
β = 111.63 (3)°T = 293 K
V = 578.1 (2) Å3Prism, green
Z = 20.15 × 0.10 × 0.10 mm
F(000) = 396
Data collection top
Nonius KappaCCD area-detector
diffractometer
1593 independent reflections
Radiation source: fine-focus sealed tube1363 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.026
Detector resolution: 9 pixels mm-1θmax = 30.0°, θmin = 4.2°
ϕ and ω scansh = 1516
Absorption correction: multi-scan
(DENZO-SMN; Otwinowski & Minor, 1997)
k = 88
Tmin = 0.310, Tmax = 0.423l = 129
3883 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.026All H-atom parameters refined
wR(F2) = 0.055 w = 1/[σ2(Fo2) + (0.0083P)2 + 0.67P]
where P = (Fo2 + 2Fc2)/3
S = 1.08(Δ/σ)max = 0.001
1593 reflectionsΔρmax = 0.78 e Å3
99 parametersΔρmin = 0.76 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0065 (8)
Crystal data top
[NiBr2(C2H5NO2)2(H2O)2]V = 578.1 (2) Å3
Mr = 404.70Z = 2
Monoclinic, P21/cMo Kα radiation
a = 11.805 (2) ŵ = 8.60 mm1
b = 6.021 (1) ÅT = 293 K
c = 8.749 (2) Å0.15 × 0.10 × 0.10 mm
β = 111.63 (3)°
Data collection top
Nonius KappaCCD area-detector
diffractometer
1593 independent reflections
Absorption correction: multi-scan
(DENZO-SMN; Otwinowski & Minor, 1997)
1363 reflections with I > 2σ(I)
Tmin = 0.310, Tmax = 0.423Rint = 0.026
3883 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0260 restraints
wR(F2) = 0.055All H-atom parameters refined
S = 1.08Δρmax = 0.78 e Å3
1593 reflectionsΔρmin = 0.76 e Å3
99 parameters
Special details top

Experimental. Single-crystal X-ray intensity data were collected at 293 K on a Nonius Kappa diffractometer with CCD area detector, using 448 frames with ϕ- and ω increments of 1° and a counting time of 40 s per frame. The crystal-to-detector-distance was 25 mm. The whole Ewald sphere was measured. The reflection data were processed with the Nonius program suite DENZO-SMN and corrected for Lorentz, polarization, background and absorption effects (Otwinowski & Minor, 1997). The crystal structure was determined by direct methods (SHELXS97; Sheldrick, 1997) and subsequent Fourier and difference Fourier syntheses, followed by full-matrix least-squares refinements on F2 (SHELXL97; Sheldrick, 1997). All H atoms were refined freely. Using anisotropic treatment of the non-H atoms and unrestrained isotropic treatment of the H atoms, the refinement converged at R values of 0.026.

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 (Å2) top
xyzUiso*/Ueq
Ni0.00000.00000.00000.01559 (12)
Br0.61040 (2)0.30093 (4)0.15240 (4)0.03038 (11)
O10.04785 (16)0.3295 (3)0.2773 (2)0.0261 (4)
O20.14349 (15)0.1270 (3)0.0527 (2)0.0209 (4)
C10.1412 (2)0.2469 (4)0.1713 (3)0.0174 (5)
C20.2619 (2)0.2863 (5)0.1893 (3)0.0250 (5)
H1C0.273 (3)0.427 (6)0.206 (4)0.038 (9)*
H2C0.261 (3)0.198 (5)0.281 (5)0.041 (9)*
N0.3666 (2)0.2119 (4)0.0448 (3)0.0250 (5)
H1N0.435 (4)0.213 (5)0.075 (4)0.041 (9)*
H2N0.353 (3)0.086 (7)0.008 (4)0.045 (10)*
H3N0.382 (3)0.311 (5)0.035 (4)0.035 (9)*
O1W0.1026 (2)0.2680 (3)0.1100 (3)0.0328 (5)
H1W0.170 (4)0.281 (6)0.125 (4)0.040 (10)*
H2W0.083 (4)0.297 (7)0.191 (5)0.062 (13)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ni0.0129 (2)0.0204 (2)0.0147 (2)0.00003 (16)0.00647 (16)0.00087 (16)
Br0.02489 (17)0.02756 (15)0.04247 (18)0.00105 (10)0.01683 (13)0.00135 (12)
O10.0189 (9)0.0392 (10)0.0216 (9)0.0068 (8)0.0092 (8)0.0110 (8)
O20.0169 (8)0.0284 (8)0.0183 (8)0.0002 (7)0.0076 (7)0.0063 (7)
C10.0179 (12)0.0188 (10)0.0171 (10)0.0015 (9)0.0082 (10)0.0009 (9)
C20.0190 (13)0.0326 (14)0.0246 (13)0.0003 (11)0.0095 (11)0.0085 (11)
N0.0186 (12)0.0329 (12)0.0250 (11)0.0006 (10)0.0099 (9)0.0046 (10)
O1W0.0241 (12)0.0380 (11)0.0424 (13)0.0104 (9)0.0193 (10)0.0170 (9)
Geometric parameters (Å, º) top
Ni—O1W2.034 (2)C1—C21.509 (3)
Ni—O1Wi2.034 (2)C2—N1.475 (4)
Ni—O22.0595 (16)C2—H1C0.87 (3)
Ni—O2i2.0595 (16)C2—H2C0.96 (4)
Ni—O1ii2.0876 (18)N—H1N0.94 (4)
Ni—O1iii2.0876 (18)N—H2N0.86 (4)
O1—C11.253 (3)N—H3N0.89 (4)
O1—Niiv2.0876 (18)O1W—H1W0.76 (4)
O2—C11.256 (3)O1W—H2W0.84 (5)
O1W—Ni—O1Wi180.0 (2)O1—C1—C2117.8 (2)
O1W—Ni—O290.28 (8)O2—C1—C2116.3 (2)
O1Wi—Ni—O289.72 (8)N—C2—C1112.8 (2)
O1W—Ni—O2i89.72 (8)N—C2—H1C108 (2)
O1Wi—Ni—O2i90.28 (8)C1—C2—H1C112 (2)
O2—Ni—O2i180.00 (4)N—C2—H2C107 (2)
O1W—Ni—O1ii87.73 (9)C1—C2—H2C107 (2)
O1Wi—Ni—O1ii92.27 (9)H1C—C2—H2C111 (3)
O2—Ni—O1ii86.31 (7)C2—N—H1N107 (2)
O2i—Ni—O1ii93.69 (7)C2—N—H2N112 (2)
O1W—Ni—O1iii92.27 (9)H1N—N—H2N115 (3)
O1Wi—Ni—O1iii87.73 (9)C2—N—H3N110 (2)
O2—Ni—O1iii93.69 (7)H1N—N—H3N106 (3)
O2i—Ni—O1iii86.31 (7)H2N—N—H3N108 (3)
O1ii—Ni—O1iii180.0Ni—O1W—H1W124 (3)
C1—O1—Niiv138.42 (16)Ni—O1W—H2W105 (3)
C1—O2—Ni128.99 (16)H1W—O1W—H2W116 (4)
O1—C1—O2125.8 (2)
Symmetry codes: (i) x, y, z; (ii) x, y+1/2, z1/2; (iii) x, y1/2, z+1/2; (iv) x, y1/2, z1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N—H1N···Br0.94 (4)2.46 (4)3.384 (2)168 (3)
N—H2N···Brv0.86 (4)2.67 (4)3.498 (2)161 (3)
N—H3N···Brvi0.89 (4)2.54 (3)3.363 (3)155 (3)
O1W—H1W···Brv0.76 (4)2.51 (4)3.275 (2)175 (4)
O1W—H2W···O1i0.84 (5)1.96 (5)2.711 (3)148 (4)
C2—H2C···Brvii0.96 (4)3.00 (5)3.780 (3)139 (3)
Symmetry codes: (i) x, y, z; (v) x+1, y, z; (vi) x+1, y1, z; (vii) x+1, y+1/2, z1/2.
(II) catena-Poly[[[tetraaquamagnesium(II)]-µ-glycine] dichloride] top
Crystal data top
[MgCl2(C2H5NO2)(H2O)4]Dx = 1.528 Mg m3
Mr = 242.34Melting point: not determined K
Orthorhombic, PnmaMo Kα radiation, λ = 0.71073 Å
a = 10.587 (2) ÅCell parameters from 2396 reflections
b = 12.899 (3) Åθ = 4.1–33.7°
c = 7.714 (2) ŵ = 0.67 mm1
V = 1053.4 (4) Å3T = 293 K
Z = 4Prism, colourless
F(000) = 5040.30 × 0.15 × 0.15 mm
Data collection top
Nonius Kappa CCD area-detector
diffractometer
2163 independent reflections
Radiation source: fine-focus sealed tube1940 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.010
Detector resolution: 9 pixels mm-1θmax = 33.8°, θmin = 4.2°
ϕ and ω scansh = 1616
Absorption correction: multi-scan
(DENZO-SMN; Otwinowski & Minor, 1997)
k = 2020
Tmin = 0.824, Tmax = 0.906l = 1212
3968 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.028All H-atom parameters refined
wR(F2) = 0.077 w = 1/[σ2(Fo2) + (0.037P)2 + 0.26P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.002
2163 reflectionsΔρmax = 0.55 e Å3
92 parametersΔρmin = 0.45 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.068 (6)
Crystal data top
[MgCl2(C2H5NO2)(H2O)4]V = 1053.4 (4) Å3
Mr = 242.34Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 10.587 (2) ŵ = 0.67 mm1
b = 12.899 (3) ÅT = 293 K
c = 7.714 (2) Å0.30 × 0.15 × 0.15 mm
Data collection top
Nonius Kappa CCD area-detector
diffractometer
2163 independent reflections
Absorption correction: multi-scan
(DENZO-SMN; Otwinowski & Minor, 1997)
1940 reflections with I > 2σ(I)
Tmin = 0.824, Tmax = 0.906Rint = 0.010
3968 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0280 restraints
wR(F2) = 0.077All H-atom parameters refined
S = 1.04Δρmax = 0.55 e Å3
2163 reflectionsΔρmin = 0.45 e Å3
92 parameters
Special details top

Experimental. Single-crystal X-ray intensity data were collected at 293 K on a Nonius Kappa diffractometer with CCD area detector, using 716 frames with ϕ and ω increments of 1° and a counting time of 90 s per frame. The crystal-to-detector-distance was 30 mm. The whole Ewald sphere was measured. The reflection data were processed with the Nonius program suite DENZO-SMN and corrected for Lorentz, polarization, background and absorption effects (Otwinowski & Minor, 1997). The crystal structure was determined by direct methods (SHELXS97; Sheldrick, 1997) and subsequent Fourier and difference Fourier syntheses, followed by full-matrix least-squares refinements on F2 (SHELXL97; Sheldrick, 1997). All H atoms were refined freely. Using anisotropic treatment of the non-H atoms and unrestrained isotropic treatment of the H atoms, the refinement converged at R values of 0.028.

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 (Å2) top
xyzUiso*/Ueq
Mg0.67555 (3)0.75000.20148 (5)0.02311 (11)
Cl0.89842 (3)0.457289 (19)0.23082 (3)0.03813 (10)
O10.33974 (9)0.75000.16603 (13)0.0353 (2)
O20.52616 (7)0.75000.03405 (11)0.02837 (18)
C10.40838 (9)0.75000.03542 (14)0.02188 (18)
C20.34260 (11)0.75000.13939 (18)0.0354 (3)
H1C0.2887 (15)0.6902 (14)0.158 (2)0.059 (5)*
N30.43307 (11)0.75000.28502 (14)0.0326 (2)
H1N0.4840 (15)0.6962 (14)0.2749 (19)0.049 (4)*
H2N0.390 (2)0.75000.381 (4)0.055 (6)*
O1W0.75655 (7)0.63822 (5)0.03703 (9)0.03242 (15)
H1W10.7908 (16)0.5900 (14)0.097 (3)0.059 (5)*
H2W10.7078 (16)0.6098 (13)0.035 (2)0.054 (4)*
O2W0.59583 (10)0.63443 (9)0.35036 (13)0.0570 (3)
H1W20.6076 (17)0.6111 (16)0.446 (3)0.061 (5)*
H2W20.544 (2)0.5985 (17)0.309 (3)0.072 (6)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mg0.01678 (16)0.0332 (2)0.01939 (17)0.0000.00104 (12)0.000
Cl0.04570 (16)0.03416 (14)0.03453 (14)0.00244 (9)0.00206 (9)0.00651 (8)
O10.0243 (4)0.0506 (6)0.0311 (4)0.0000.0097 (3)0.000
O20.0157 (3)0.0471 (5)0.0224 (3)0.0000.0016 (3)0.000
C10.0166 (4)0.0256 (4)0.0234 (4)0.0000.0003 (3)0.000
C20.0182 (4)0.0587 (8)0.0294 (5)0.0000.0046 (4)0.000
N30.0287 (5)0.0463 (6)0.0228 (4)0.0000.0048 (4)0.000
O1W0.0331 (3)0.0333 (3)0.0308 (3)0.0057 (2)0.0064 (2)0.0035 (2)
O2W0.0542 (5)0.0763 (7)0.0405 (4)0.0359 (5)0.0141 (4)0.0254 (4)
Geometric parameters (Å, º) top
Mg—O1i2.0165 (10)C1—C21.5178 (17)
Mg—O22.0420 (9)C2—N31.4762 (18)
Mg—O2Wii2.0624 (9)C2—H1C0.970 (17)
Mg—O2W2.0624 (9)N3—H1N0.882 (18)
Mg—O1W2.1032 (8)N3—H2N0.87 (3)
Mg—O1Wii2.1032 (8)O1W—H1W10.858 (19)
O1—C11.2423 (14)O1W—H2W10.841 (18)
O1—Mgiii2.0165 (10)O2W—H1W20.81 (2)
O2—C11.2469 (12)O2W—H2W20.79 (2)
O1i—Mg—O2171.22 (4)C1—O2—Mg140.28 (8)
O1i—Mg—O2Wii94.04 (4)O1—C1—O2126.29 (11)
O2—Mg—O2Wii92.02 (4)O1—C1—C2116.88 (10)
O1i—Mg—O2W94.04 (4)O2—C1—C2116.83 (10)
O2—Mg—O2W92.02 (4)N3—C2—C1112.23 (9)
O2Wii—Mg—O2W92.58 (8)N3—C2—H1C105.7 (11)
O1i—Mg—O1W87.38 (3)C1—C2—H1C113.5 (11)
O2—Mg—O1W86.23 (3)C2—N3—H1N109.2 (10)
O2Wii—Mg—O1W176.59 (4)C2—N3—H2N108.0 (16)
O2W—Mg—O1W90.41 (5)H1N—N3—H2N113.2 (13)
O1i—Mg—O1Wii87.38 (3)Mg—O1W—H1W1110.0 (13)
O2—Mg—O1Wii86.23 (3)Mg—O1W—H2W1116.5 (11)
O2Wii—Mg—O1Wii90.41 (5)H1W1—O1W—H2W1107.5 (17)
O2W—Mg—O1Wii176.59 (4)Mg—O2W—H1W2135.7 (14)
O1W—Mg—O1Wii86.56 (5)Mg—O2W—H2W2119.2 (16)
C1—O1—Mgiii156.26 (9)H1W2—O2W—H2W2105 (2)
Mg—O2—C1—C2180.000 (1)O2—C1—C2—N30.0
O1iii—C1—C2—N3180.0
Symmetry codes: (i) x+1/2, y, z+1/2; (ii) x, y+3/2, z; (iii) x1/2, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H1N···Cliv0.882 (18)2.339 (18)3.2167 (9)173.1 (15)
N3—H2N···O1Wv0.87 (3)2.35 (2)3.0579 (13)139 (1)
O1W—H1W1···Cl0.858 (19)2.299 (19)3.1523 (9)173.0 (17)
O1W—H2W1···Cliv0.841 (18)2.298 (18)3.1287 (9)169.2 (16)
O2W—H1W2···Clvi0.81 (2)2.37 (2)3.1649 (12)169.6 (17)
O2W—H2W2···Cliii0.79 (2)2.40 (2)3.1593 (11)161 (2)
Symmetry codes: (iii) x1/2, y, z+1/2; (iv) x+3/2, y+1, z1/2; (v) x1/2, y, z1/2; (vi) x+3/2, y+1, z+1/2.

Experimental details

(I)(II)
Crystal data
Chemical formula[NiBr2(C2H5NO2)2(H2O)2][MgCl2(C2H5NO2)(H2O)4]
Mr404.70242.34
Crystal system, space groupMonoclinic, P21/cOrthorhombic, Pnma
Temperature (K)293293
a, b, c (Å)11.805 (2), 6.021 (1), 8.749 (2)10.587 (2), 12.899 (3), 7.714 (2)
α, β, γ (°)90, 111.63 (3), 9090, 90, 90
V3)578.1 (2)1053.4 (4)
Z24
Radiation typeMo KαMo Kα
µ (mm1)8.600.67
Crystal size (mm)0.15 × 0.10 × 0.100.30 × 0.15 × 0.15
Data collection
DiffractometerNonius KappaCCD area-detector
diffractometer
Nonius Kappa CCD area-detector
diffractometer
Absorption correctionMulti-scan
(DENZO-SMN; Otwinowski & Minor, 1997)
Multi-scan
(DENZO-SMN; Otwinowski & Minor, 1997)
Tmin, Tmax0.310, 0.4230.824, 0.906
No. of measured, independent and
observed [I > 2σ(I)] reflections
3883, 1593, 1363 3968, 2163, 1940
Rint0.0260.010
(sin θ/λ)max1)0.7030.782
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.026, 0.055, 1.08 0.028, 0.077, 1.04
No. of reflections15932163
No. of parameters9992
H-atom treatmentAll H-atom parameters refinedAll H-atom parameters refined
Δρmax, Δρmin (e Å3)0.78, 0.760.55, 0.45

Computer programs: COLLECT (Bruker Nonius, 2003), HKL SCALEPACK (Otwinowski & Minor 1997), HKL DENZO (Otwinowski & Minor, 1997) and SCALEPACK, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), DIAMOND (Version 2.1; Bergerhoff et al., 1996), SHELXL97.

Selected geometric parameters (Å, º) for (I) top
Ni—O1W2.034 (2)Ni—O1i2.0876 (18)
Ni—O22.0595 (16)
O1W—Ni—O1Wii180.0 (2)O1Wii—Ni—O1i92.27 (9)
O1W—Ni—O290.28 (8)O2—Ni—O1i86.31 (7)
O1Wii—Ni—O289.72 (8)O2ii—Ni—O1i93.69 (7)
O2—Ni—O2ii180.00 (4)O1i—Ni—O1iii180.0
O1W—Ni—O1i87.73 (9)
Symmetry codes: (i) x, y+1/2, z1/2; (ii) x, y, z; (iii) x, y1/2, z+1/2.
Hydrogen-bond geometry (Å, º) for (I) top
D—H···AD—HH···AD···AD—H···A
N—H1N···Br0.94 (4)2.46 (4)3.384 (2)168 (3)
N—H2N···Briv0.86 (4)2.67 (4)3.498 (2)161 (3)
N—H3N···Brv0.89 (4)2.54 (3)3.363 (3)155 (3)
O1W—H1W···Briv0.76 (4)2.51 (4)3.275 (2)175 (4)
O1W—H2W···O1ii0.84 (5)1.96 (5)2.711 (3)148 (4)
C2—H2C···Brvi0.96 (4)3.00 (5)3.780 (3)139 (3)
Symmetry codes: (ii) x, y, z; (iv) x+1, y, z; (v) x+1, y1, z; (vi) x+1, y+1/2, z1/2.
Selected geometric parameters (Å, º) for (II) top
Mg—O1i2.0165 (10)Mg—O2W2.0624 (9)
Mg—O22.0420 (9)Mg—O1W2.1032 (8)
O1i—Mg—O2171.22 (4)O2—Mg—O1W86.23 (3)
O1i—Mg—O2W94.04 (4)O2Wii—Mg—O1W176.59 (4)
O2—Mg—O2W92.02 (4)O2W—Mg—O1W90.41 (5)
O2Wii—Mg—O2W92.58 (8)O1W—Mg—O1Wii86.56 (5)
O1i—Mg—O1W87.38 (3)
Symmetry codes: (i) x+1/2, y, z+1/2; (ii) x, y+3/2, z.
Hydrogen-bond geometry (Å, º) for (II) top
D—H···AD—HH···AD···AD—H···A
N3—H1N···Cliii0.882 (18)2.339 (18)3.2167 (9)173.1 (15)
N3—H2N···O1Wiv0.87 (3)2.35 (2)3.0579 (13)138.6 (9)
O1W—H1W1···Cl0.858 (19)2.299 (19)3.1523 (9)173.0 (17)
O1W—H2W1···Cliii0.841 (18)2.298 (18)3.1287 (9)169.2 (16)
O2W—H1W2···Clv0.81 (2)2.37 (2)3.1649 (12)169.6 (17)
O2W—H2W2···Clvi0.79 (2)2.40 (2)3.1593 (11)161 (2)
Symmetry codes: (iii) x+3/2, y+1, z1/2; (iv) x1/2, y, z1/2; (v) x+3/2, y+1, z+1/2; (vi) x1/2, y, z+1/2.
A comparison of the stoichiometries, symmetries and unit-cell parameters of glycine divalent metal halogenides (Å and °) top
CompoundabcαβγSpace groupReference
Glycine MgCl2·4H2O10.5912.907.71909090Pnma(a)
Glycine CaCl214.7719.579.07909090Pb21a(b)
Glycine BaCl2·H2O8.3114.849.32909090Pbcn(c)
Glycine SrCl2·3H2O16.429.358.26909090Pbcn(c)
Glycine MnCl24.977.926.98107.4115.987.0P1(c)
Glycine MnCl2·2H2O8.405.6116.799090.290P21/c(d)
Glycine CoCl2·2H2O6.3815.887.759097.690P21/n(d)
Glycine2 CoCl2·2H2O10.575.998.849091.690P21/c(e)
Glycine NiCl28.215.488.319091.090P21(f)
Glycine ZnCl211.2315.2515.66909090Pbn21(g)
Glycine2 PtCl2·2H2O5.367.058.4485.775.971.7P1(h)
Glycine3 CaBr29.1514.8420.31909090Pbc21(i)
Glycine2 MnBr2·2H2O21.6112.658.99909090Pbca(j)
Glycine2 MnBr2·2H2O11.946.068.9890111.790P21/c(j)
Glycine2 CoBr2·2H2O11.776.068.8290111.590P21/c(k)
Glycine2 MgBr2·2H2O11.846.078.8390111.990P21/c(l)
Glycine2 NiBr2·2H2O11.816.028.7590111.690P21/c(a)
References: (a) this work; (b) Ravikumar et al. (1986); (c) Narayanan & Venkataraman (1975); (d) Clegg et al. (1987); (e) Stenzel & Fleck (2004); (f) Fleck & Bohatý (2004); (g) Hariharan et al. (1989); (h) Davies et al. (1995); (i) Mohana Rao & Natarajan (1980); (j) Głowiak & Ciunik (1978); (k) Ravikumar et al. (1985); (l) Krishnakumar & Natarajan (1995).
 

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