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The structure of the title centrosymmetric compound, [Zn(C9H6NO)2(H2O)2], has already been solved three times [Merritt, Cady & Mundy (1954). Acta Cryst. 7, 473-476; Palenik (1964). Acta Cryst. 17, 696-700; Chen, Zhang, Shi, Huang, Liang & Zhou (2003). Acta Cryst. E59, m814-m815]. The authors of the two most recent papers state that they attained lower R1 values than that obtained in the 1954 paper, but they do not mention that Merritt et al. had derived the structural model from a twinned crystal. Also, from a structural point of view, there are strong indications that the most recent report is in fact the isostructural CuII complex already reported by Okabe & Saishu [Acta Cryst. (2001), E57, m251-m252] and not the ZnII complex. The structure of the title compound is reported here based on data obtained from a twinned crystal.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113018386/sk3496sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270113018386/sk3496Isup2.hkl
Contains datablock I

CCDC reference: 962903

Introduction top

8-Hy­droxy­quinoline (and derivatives thereof) is an aromatic Lewis base, acting as an efficient metal ion chelator. To this end, its metal cycle-forming abilities and the ensuing metal ionic complex stabilization (i) impart significant electronic properties to the resulting metal complex(es), which are useful in qu­anti­tative analytical determinations (Schneider & Roselli, 1970; Uri et al., 1957) and (ii) have rendered it useful in anti­microbial and fungicidal applications (Patel et al., 1999; Okide et al., 2000). The present crystal structure analysis of the title compound, (I), based on a twinned crystal, has revealed inter­esting methodological processing steps which are related to the basis of twinning theory, i.e. the existence in the lattice of a cell, simple or multiple, endowed either rigorously or approximately with more symmetry than the crystal (Donnay, 1940; Grimmer & Nespolo, 2006). In a recent publication (Guzei et al., 2012), which presents a detailed description of the steps needed to tackle structure solution and refinement problems from a data set obtained from pseudomerohedral twins, it was noted that the reason for this elaborate presentation was the lack of papers written in the form of tutorials with technical details on how to handle such cases. The motivation for writing the present paper is that, although there are pioneering works (Herbst-Irmer & Sheldrick, 1998; Cooper et al., 2002; Blake et al., 2009; Muller et al., 2007) that have boosted tremendously the field of structure solution and refinement from twinned crystals and works on the geometric theory of twinning (Donnay, 1940; Santoro, 1974; Grimmer & Nespolo, 2006), there is also a lack of works that combine both of these approaches in the study of twins. This combination provides an appropriate framework to peruse, understand and overcome problems during the structure analysis of a twinned crystal.

Experimental top

Synthesis and crystallization top

A reaction mixture containing zinc(II) nitrate (1.0 mmol), quinolin-8-ol (1 mmol) and 2-(2-hy­droxy­naphthalen-1-yl­idene­imino)-2-hy­droxy­methyl­propane-1,3-diol (1 mmol) in methanol led immediately to a precipitate. Dissolution of the isolated precipitate in di­methyl sulfoxide (DMSO) afforded pale-yellow single crystals of (I) by slow evaporation at room temperature over a period of several weeks. The crystals were isolated by filtration and air-dried (yield 37%).

Refinement top

Crystal data, data collection and structure refinement details are summarized in Table 1. All H atoms were located in difference maps. C-bound H atoms were then treated as riding in geometrically idealized positions, with C—H = 0.95 Å and with Uiso(H) = 1.3Ueq(C). The hy­droxy H atoms were refined freely.

Results and discussion top

Initially, index processing of images recorded from the studied crystal of (I), which present no indication for peak splitting, gave rise to a primitive unit cell with dimensions a = 11.099, b = 5.404 and c = 37.917 Å, and α = 90, β = 90.03 and γ = 90°, i.e. a seemingly orthorhombic cell. Using these cell dimensions in a search of the Cambridge Structural Database (CSD, Version 5.34; Allen, 2002), no structure was found containing any of the ligands used in the present study, indicating that the studied compound is a new one.

The structure was solved using direct methods in the monoclinic space group P21/a, a result which supports the slight deviation of β from 90°. In the asymmetric unit of the cell there are one and half molecules of the complex shown in the scheme. One ZnII cation is located on a general position, whereas the other one sits on a centre of symmetry. These two complexes are related by a noncrystallographic centre of symmetry, which renders the resulting structural model a pseudosymmetric one (Zwart et al., 2008). All data manipulations revealed almost all of the known warning signs of twinning (Herbst-Irmer & Sheldrick, 1998). The model was refined by considering the crystal as a pseudomerohedral twin (Castillo et al. 2010). The twin law is linked to a 180° rotation around the c crystallographic axis and in matrix form is (100/010/001). The main problem in the data analysis of this model was that the observed reflections were approximately half of the total unique reflections. A search of the CSD using the derived structural model revealed three previous structural studies (Merritt et al., 1954; Palenik, 1964; Chen et al., 2003). In Table 2, the unit-cell dimensions are given for all three published structural models. However, the pseudosymmetry characteristics of the present structural model raised suspicions as to the potential existence of a structure–superstructure relation between the models described in the monoclinic cell given in Table 2 and the pseudo-orthorhombic one emerging from our analysis.

Le Page (2002) has developed an algorithm and reformulated Mallard's law for the possible existence of a twin law in a lattice as a Diophantine system of two conditions: h.u = n and |h × u| < ntanδ, where n and δ meet Mallard's criterion limitations (n < 6 and ω < 6°; Grimmer & Nespolo, 2006), and h and u are reciprocal and direct lattice directions, respectively. Applying Le Page's algorithm as implemented in PLATON (Spek, 2009) for the monoclinic cell dimensions listed in Table 2, a supercell with dimensions a = 11.113, b = 5.411 and c = 37.967 Å, and α = 90, β = 90.06 and γ = 90° is obtained. The two cells are related through the transformation (a', b', c') = (a, b, a + 3c). This unit cell corresponds to the pseudo-orthorhombic unit cell initially used by us for solving the structure of (I).

Fig. 1(a) shows the structure–superstructure cell relationship. Primed axes concern the pseudo-orthorhombic cell and unprimed ones the monoclinic cell. This process also gives the h = (001) (possible mirror plane) and u = [103] (possible twofold axis) reciprocal and direct lattice vectors, respectively, for the lattices defined by the cells listed in Table 2, with n = 3 and δ < 0.13°. The perpendicularity condition (Donnay, 1940) for the monoclinic system and for vectors (hkl) = (001) and [uvw] = [103] affords [a/(ccosβ)] ~-3. Rearrangement of this equation yields [a/(3c)] = -cosβ, i.e. the relation joining a, c and β mentioned by Merritt et al. (1954). The calculated values of the [a/(ccosβ)] parameter for all data sets are given in the last column of Table 2.

Finally, using equation 5 given by Andrews & Johnson (1955) for (hkl) = (001) and [uvw] = [103], or in the equivalent tensorial form equation 2 of Calbick (1967), the two possible twin laws are derived. Either (001) is a twinning mirror plane and the twin law is (h2,k2,l2) = (h1,k1, (-2/3)h1-l1), or the [103] crystallographic direction is a 180° rotation twin axis and the twin law is (h2,k2,l2) = (-h1,-k1, (2/3)h1+l1). Equations 5 and 2 of the above-mentioned references refer to the case of a mirror twin plane. According to Calbick (1967), the same equations apply in the case of a 180° rotation twin axis by reversing the minus and plus signs in both of them.

This ambiguity concerning the twin law, which ultimately applies for the crystal of (I) studied here, is resolved experimentally. Reindexing of images was performed with the procedure implemented in the TwinSolve (Rigaku/MSC, 2002) environment of the CrystalClear program (Rigaku/MSC, 2005), and orientation matrices for components 1 and 2 were obtained. By applying the formula A2-1A1 (Bolte, 2004), the twin law (-1.000, 0.001, -0.001/0.000, -1.000, 0.000/0.668, 0.002, 1.000) of the 180° rotation axis around the [103] crystallographic direction (or around the c*) is derived. The data obtained with image integration taking into account only component 1 (including overlapped reflections) gave a structure solution, but the refinement was unsuccessful and the usual warning signs of twinning were present [low |E2 - 1| value (= 0.715), K high for reflections with low intensity, |Fo| > |Fc| with most of them belonging to the family of reflections with h = 3n, and high residual electron-density peaks]. Analysis of the data with PLATON suggests the same twin law as given above.

According to the twin law, reflections with h1 = 3n from the first crystallite overlap with reflections l2 = (2/3)h1 + l1 (where l2 is an integer) of the second crystallite, thereby explaining the fact that, for this family of reflections, |Fo| > |Fc|. These index relationships, taking into account the space group of the structure, also explain the observation by Merritt et al. that the h0l Weissenberg photograph for every third layer where h = 0, 6 or 12 consists of single spots, whereas otherwise the spots are doublets.

The final structural model for (I) emerged through refinement of data obtained using the TwinSolve data-reduction program (HKLF5 file containing merged reflections from component 1, plus only the overlapped reflections with component 2). The fractions are 0.370 (3) and 0.630 (3). This result classifies the studied crystal as a non-merohedral twin. It is worth mentioning that, using the HKLF5 file derived directly from TwinSolve, the PLATON method for twin law derivation is by-passed. Thus, the geometrically derived law could serve as a very useful tool in the analysis of a structure from a twinned crystal. Fig. 1(b) presents a section of the reciprocal lattice showing clearly the overlap of peaks with h = 3n.

The structure of (I) consists of a ZnII cation, sitting on centre of symmetry, o­cta­hedrally coordinated (Fig. 2) by two deprotonated quinolin-8-olate ligands and two water molecules trans to each other in the equatorial and axial positions, respectively. Selected bond lengths and angles for all data sets are listed in Table 3. The Zn—O1 bond to the deprotonated hy­droxy O atom and the Zn—N bond to the pyridine N atom of the quinolin-8-olate ligand are 2.062 (2) and 2.103 Å, respectivelly. The Zn—O2 bond, involving the water molecule, is 2.220 Å, slightly longer than Zn—O1, indicative of a weak zinc–water bond, resulting in easy dehydration (Merritt et al., 1954). These bond lengths are in agreement, within experimental error, amongst themselves in the three data sets [Table 3; present study, Merritt et al. (1954) and Palenik (1964)], but they differ significantly from the corresponding values of the fourth set (Table 3; Chen et al., 2003). The difference is largest for the bond length to water atom O2; Chen et al. report a value of 2.451 Å for this bond. The bond length and angle values given by Chen et al. (Table 3), together with the published unit-cell dimensions (Table 2), are closer to the corresponding values of the analogous CuII compound (Okabe & Saishu, 2001; Tables 2 and 3). Both compounds, viz. [Zn(C9H6NO)2(H2O)2] and [Cu(C9H6NO)2(H2O)2], are isostructural. The axial distortion in o­cta­hedrally coordinated CuII compounds is characteristic of the Jahn–Teller effect (Feng et al., 2007). A systematic search of the CSD shows that the values derived from the three data sets [Table 3; present study, Merritt et al. (1954) and Palenik (1964)] are characteristic of ZnII compounds and those of the fourth data set are characteristic of CuII compounds. Furthermore, in the checkCIF report concerning Chen's study, an Alert comment is reported, related to the Hirshfeld test for the wrong assignment of atom species.

Another issue concerning the present structure is related to hydrogen-bond formation, which is adequately described in all previous papers. Merritt et al. (1954) ruled out the possibility of hydrogen-bond formation, based on the observation that (i) the inter­molecular distances between adjacent water molecules and the closest approach of the C atoms are too long, and (ii) they did not take into account the possibility of hydrogen-bond formation between the coordinated water of one molecule and the deprotonated hy­droxy O atom of the quinolin-8-olate ligand of an adjacent complex. Palenik (1964) did discuss this possibility, and Chen et al. (2003) discussed hydrogen-bond formation in an incorrect way. Finally, Okabe & Saishu (2001), in their study of the isostructural compound with CuII, reported the correct hydrogen-bond paths and values, but they did not discuss at all the network arising through those hydrogen bonds. The H atoms of the coordinated water molecules form hydrogen bonds (Table 4) with the deprotonated O atoms of the quinolin-8-olate ligands of neighbouring complexes, thereby giving rise to layers parallel to the (001) crystallographic plane (Fig. 3).

Related literature top

For related literature, see: Allen (2002); Andrews & Johnson (1955); Blake et al. (2009); Bolte (2004); Calbick & ? (1967); Castillo et al. (2010); Chen et al. (2003); Cooper et al. (2002); Donnay (1940); Feng et al. (2007); Grimmer & Nespolo (2006); Guzei et al. (2012); Herbst-Irmer & Sheldrick (1998); Le Page (2002); Merritt et al. (1954); Muller et al. (2007); Okabe & Saishu (2001); Okide et al. (2000); Palenik (1964); Patel et al. (1999); Rigaku/MSC (2002, 2005); Santoro (1974); Schneider & Roselli (1970); Spek (2009); Uri et al. (1957); Zwart et al. (2008).

Computing details top

Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: TwinSolve (Rigaku/MSC, 2002); data reduction: TwinSolve (Rigaku/MSC, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Crystal Impact, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. (a) A schematic presentation of the monoclinic cell (unprimed axes) and pseudo-orthorhombic cell (primed axes), showing the cell–supercell relationship. (b) A section of the reciprocal lattice, which shows the overlapped (h = 3n) and non-overlapped (h ≠ 3n) reflections of the two crystallites in the twinned crystal. Peaks outlined in lighter (green in the electronic version of the paper) and darker (blue) circles correspond to the two orientations of the crystallites.
[Figure 2] Fig. 2. A view of the molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.
[Figure 3] Fig. 3. The layers of molecules of (I) parallel to the (001) plane formed through hydrogen-bond interactions. Dashed lines indicate hydrogen bonds.
Diaquabis(quinolin-8-olato-κ2N,O)zinc(II) top
Crystal data top
[Zn(C9H6NO)2(H2O)2]F(000) = 400
Mr = 389.70Dx = 1.701 Mg m3
Monoclinic, P21/aCu Kα radiation, λ = 1.54178 Å
Hall symbol: -P 2yabCell parameters from 15184 reflections
a = 11.1132 (4) Åθ = 2.5–70.0°
b = 5.4109 (2) ŵ = 2.49 mm1
c = 13.1888 (5) ÅT = 160 K
β = 106.370 (2)°Plate, pale yellow
V = 760.92 (5) Å30.22 × 0.09 × 0.04 mm
Z = 2
Data collection top
Rigaku R-AXIS SPIDER image-plate
diffractometer
1289 independent reflections
Radiation source: fine-focus sealed tube1171 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.000
θ scansθmax = 65.0°, θmin = 3.5°
Absorption correction: multi-scan
(TwinSolve; Rigaku/MSC, 2002)
h = 013
Tmin = 0.669, Tmax = 1.000k = 06
1289 measured reflectionsl = 1514
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.034Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.091H atoms treated by a mixture of independent and constrained refinement
S = 1.15 w = 1/[σ2(Fo2) + (0.0248P)2 + 2.2136P]
where P = (Fo2 + 2Fc2)/3
1289 reflections(Δ/σ)max = 0.009
124 parametersΔρmax = 0.28 e Å3
0 restraintsΔρmin = 0.33 e Å3
Crystal data top
[Zn(C9H6NO)2(H2O)2]V = 760.92 (5) Å3
Mr = 389.70Z = 2
Monoclinic, P21/aCu Kα radiation
a = 11.1132 (4) ŵ = 2.49 mm1
b = 5.4109 (2) ÅT = 160 K
c = 13.1888 (5) Å0.22 × 0.09 × 0.04 mm
β = 106.370 (2)°
Data collection top
Rigaku R-AXIS SPIDER image-plate
diffractometer
1289 independent reflections
Absorption correction: multi-scan
(TwinSolve; Rigaku/MSC, 2002)
1171 reflections with I > 2σ(I)
Tmin = 0.669, Tmax = 1.000Rint = 0.000
1289 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0340 restraints
wR(F2) = 0.091H atoms treated by a mixture of independent and constrained refinement
S = 1.15Δρmax = 0.28 e Å3
1289 reflectionsΔρmin = 0.33 e Å3
124 parameters
Special details top

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
Zn10.00000.00000.00000.0123 (2)
O10.0873 (2)0.2534 (5)0.07268 (19)0.0154 (5)
N10.0804 (3)0.1112 (5)0.1573 (2)0.0140 (7)
C10.1580 (3)0.2930 (7)0.1968 (3)0.0171 (8)
H10.18400.39950.14970.022*
C20.2046 (3)0.3366 (7)0.3074 (3)0.0199 (9)
H20.26040.47000.33330.026*
C30.1681 (3)0.1840 (7)0.3757 (3)0.0203 (9)
H30.19960.20880.44980.026*
C40.0381 (4)0.1749 (7)0.4009 (3)0.0201 (9)
H40.06680.15990.47560.026*
C50.0471 (4)0.3544 (7)0.3554 (3)0.0220 (9)
H50.07760.46260.39920.029*
C60.0902 (3)0.3813 (7)0.2450 (3)0.0181 (8)
H60.14980.50670.21610.024*
C70.0488 (3)0.2321 (7)0.1775 (3)0.0126 (7)
C80.0401 (3)0.0401 (6)0.2248 (3)0.0142 (8)
C90.0830 (3)0.0117 (7)0.3357 (3)0.0159 (8)
O20.1509 (2)0.2717 (5)0.0034 (2)0.0215 (6)
H70.133 (5)0.421 (10)0.021 (4)0.035 (14)*
H80.230 (4)0.267 (8)0.026 (3)0.018 (11)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Zn10.0130 (3)0.0101 (3)0.0130 (4)0.0036 (3)0.0025 (3)0.0001 (3)
O10.0178 (13)0.0123 (12)0.0149 (13)0.0029 (11)0.0026 (10)0.0000 (11)
N10.0145 (15)0.0078 (14)0.0201 (17)0.0006 (12)0.0053 (12)0.0019 (13)
C10.0138 (17)0.0138 (19)0.021 (2)0.0013 (15)0.0013 (15)0.0009 (15)
C20.0141 (17)0.0148 (18)0.027 (2)0.0006 (15)0.0006 (15)0.0052 (16)
C30.0189 (18)0.019 (2)0.019 (2)0.0056 (17)0.0020 (15)0.0038 (16)
C40.0228 (19)0.022 (2)0.015 (2)0.0043 (17)0.0054 (15)0.0007 (16)
C50.0195 (18)0.023 (2)0.025 (2)0.0009 (17)0.0089 (17)0.0061 (17)
C60.0128 (17)0.0190 (19)0.023 (2)0.0016 (16)0.0052 (15)0.0027 (16)
C70.0076 (15)0.0108 (17)0.0176 (19)0.0017 (14)0.0008 (13)0.0033 (15)
C80.0146 (17)0.0109 (18)0.017 (2)0.0049 (14)0.0046 (14)0.0009 (15)
C90.0174 (18)0.0152 (18)0.016 (2)0.0045 (16)0.0057 (14)0.0021 (16)
O20.0134 (13)0.0103 (13)0.0390 (17)0.0000 (11)0.0046 (12)0.0068 (13)
Geometric parameters (Å, º) top
Zn1—O12.065 (2)C3—C91.419 (5)
Zn1—O1i2.065 (2)C3—H30.9500
Zn1—N12.102 (3)C4—C51.371 (6)
Zn1—N1i2.102 (3)C4—C91.417 (5)
Zn1—O22.221 (3)C4—H40.9500
Zn1—O2i2.221 (3)C5—C61.406 (5)
O1—C71.332 (4)C5—H50.9500
N1—C11.315 (5)C6—C71.373 (5)
N1—C81.374 (5)C6—H60.9500
C1—C21.422 (5)C7—C81.448 (5)
C1—H10.9500C8—C91.413 (5)
C2—C31.365 (6)O2—H70.87 (5)
C2—H20.9500O2—H80.84 (4)
O1—Zn1—O1i180.0C2—C3—C9119.8 (3)
O1—Zn1—N181.76 (10)C2—C3—H3120.1
O1i—Zn1—N198.25 (10)C9—C3—H3120.1
O1—Zn1—N1i98.24 (10)C5—C4—C9119.6 (4)
O1i—Zn1—N1i81.76 (10)C5—C4—H4120.2
N1—Zn1—N1i180.0C9—C4—H4120.2
O1—Zn1—O290.11 (10)C4—C5—C6121.2 (4)
O1i—Zn1—O289.89 (10)C4—C5—H5119.4
N1—Zn1—O293.50 (11)C6—C5—H5119.4
N1i—Zn1—O286.50 (11)C7—C6—C5122.1 (4)
O1—Zn1—O2i89.89 (10)C7—C6—H6118.9
O1i—Zn1—O2i90.11 (10)C5—C6—H6118.9
N1—Zn1—O2i86.50 (11)O1—C7—C6123.6 (3)
N1i—Zn1—O2i93.50 (11)O1—C7—C8119.3 (3)
O2—Zn1—O2i180.0C6—C7—C8117.1 (3)
C7—O1—Zn1111.6 (2)N1—C8—C9122.0 (3)
C1—N1—C8119.0 (3)N1—C8—C7117.1 (3)
C1—N1—Zn1130.9 (3)C9—C8—C7120.9 (3)
C8—N1—Zn1110.1 (2)C8—C9—C4119.1 (3)
N1—C1—C2122.6 (4)C8—C9—C3117.4 (3)
N1—C1—H1118.7C4—C9—C3123.5 (3)
C2—C1—H1118.7Zn1—O2—H7121 (3)
C3—C2—C1119.1 (3)Zn1—O2—H8134 (3)
C3—C2—H2120.5H7—O2—H8106 (4)
C1—C2—H2120.5
Symmetry code: (i) x, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H7···O1ii0.87 (5)1.91 (5)2.777 (4)178
O2—H8···O1iii0.85 (5)1.95 (5)2.796 (3)177
Symmetry codes: (ii) x, y1, z; (iii) x+1/2, y1/2, z.

Experimental details

Crystal data
Chemical formula[Zn(C9H6NO)2(H2O)2]
Mr389.70
Crystal system, space groupMonoclinic, P21/a
Temperature (K)160
a, b, c (Å)11.1132 (4), 5.4109 (2), 13.1888 (5)
β (°) 106.370 (2)
V3)760.92 (5)
Z2
Radiation typeCu Kα
µ (mm1)2.49
Crystal size (mm)0.22 × 0.09 × 0.04
Data collection
DiffractometerRigaku R-AXIS SPIDER image-plate
diffractometer
Absorption correctionMulti-scan
(TwinSolve; Rigaku/MSC, 2002)
Tmin, Tmax0.669, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
1289, 1289, 1171
Rint0.000
(sin θ/λ)max1)0.588
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.034, 0.091, 1.15
No. of reflections1289
No. of parameters124
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.28, 0.33

Computer programs: CrystalClear (Rigaku/MSC, 2005), TwinSolve (Rigaku/MSC, 2002), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Crystal Impact, 2012).

Unit-cell dimensions for structural studies of ZnII and CuII compounds top
Space groupa (Å)b (Å)c (Å)β (°)V3)-a/(ccosβ)gReference
P21/aa11.285.4213.16106.3772.233.05(a)
P21/cb13.165.4211.28106.3772.23(b)
P21/cc12.9555.54611.423106.288786.8(c)
P21/ad11.4235.54612.955106.288786.83.14(d)
P21/ae11.4255.54212.950106.39786.7(e)
P21/af11.11345.411213.1906106.371761.082.99(f)
References: (a) Merritt et al. (1954); (b) Palenik (1964); (c) Chen (2003); (d) same as in (c) but with a and c axes interchanged in order to mach the space-group change; (e) Okabe & Saishu (2001); (f) this work; (g) for an explanation of this relation, see text.
Selected geometric parameters for all studied ZnII and CuII compounds top
ParameterCompound?Compound?Compound?Compound?Compound?
Zn—O12.052.0661.966 (2)1.966 (2)2.065 (2)
Zn—N12.062.0992.011 (2)2.013 (2)2.102 (3)
Zn1—O22.272.2632.451 (2)2.451 (2)2.221 (3)
N1—Zn1—O287.386.786.61 (8)86.33 (6)86.5 (1)
O1—Zn1—O285.489.289.25 (8)89.12 (6)89.9 (1)
N1—Zn1—O179.881.583.87 (9)83.70 (6)81.8 (1)
References:(a) Merritt et al. (1954); (b) Palenik (1964); (c) Chen et al. (2003); (d) Okabe & Saishu (2001); (e) this work.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H7···O1i0.87 (5)1.91 (5)2.777 (4)178
O2—H8···O1ii0.85 (5)1.95 (5)2.796 (3)177
Symmetry codes: (i) x, y1, z; (ii) x+1/2, y1/2, z.
 

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