Calcium and strontium salts of (glycinato-κ²N,O)oxidobis(peroxido-κ²O,O′)vanadate(V) tetra­hydrate

The title salts calcium (glycinato-κ²N,O)oxidobis(peroxido-κ²O,O′)vanadate(V) tetra­hydrate, Ca[VO(O₂)₂(NH₂CH₂COO)]·4H₂O, and strontium (glycinato-κ²N,O)oxidobis(peroxido-κ²O,O′)vanadate(V) tetra­hydrate, Sr[VO(O₂)₂(NH₂CH₂COO)]·4H₂O, crystallized at pH ca 7.4 with similar lattice parameters. The glycinate anion acts as a bidentate N,O-chelating ligand, and the V atom has a penta­gonal bipyramidal geometry, with two η²-peroxo groups and the glycinate N atom in the equatorial plane, and one terminal oxo and a glycinate O atom at the axial positions. The H atoms of three of the four water mol­ecules in the strontium salt exhibited disorder over three positions for each mol­ecule.

S1. Introduction

The chemistry of vanadium complexes is important from the biological point of view. Several vanadium complexes have so far been explored to reveal biological functions, such as insulin-mimetic and enzymic behaviour (Rehder, 2008).

Glycine is the simplest amino acid and may be a good target to investigate the inter­action between vanadium and amino acids. Attempt to isolate a glycinate complex of peroxovanadate at physiological pH range led to crystallization of the entitled mononuclear complex [VO(O₂)₂(NH₂CH₂COO)]^2-, (I), as a calcium salt tetra­hydrate, (I.Ca), and a strontium salt tetra­hydrate, (I.Sr).

S2. Experimental

S2.1. Synthesis and crystallization

Sodium metavanadate (1.93 g, 15.8 mmol) or ammonium metavanadate (1.85 g, 15.8 mmol) and glycine (2.25 g, 31.6 mmol) were added to water (30 ml). Hydrogen peroxide (30%, 20 ml, 0.20 mol) was added to the suspended solution under stirring. The pH of the solution was adjested by 1.0 M KOH to ca 7.4 immediately. Then the mixture was cooled in an iced bath before a vigorous reaction initiated, and was cooled for several hours in the dark. The volume was then adjusted to 100 ml with water. To the orange clear solution was added 10 ml of 1.0 M calcium chloride [for (I.Ca)] or strontium chloride [for (I.Sr)] aqueous solution.

Ethanol (20 ml) was then added and the resulted mixture was kept in the dark at room temperature. Yellow block-shaped crystals appeared within several hours [yield: 46% for (I.Ca) and 58% for (I.Sr)].

NMR data were collected on Jeol JNM400 spectrometer at 294 K. The ⁵¹V chemical shift was referred to external VOCl₃ as 0.0 p.p.m. and the signal of [V₄O₁₂]^4- at -574 p.p.m. was used as an inter­nal standard. Care should be taken to prepare the solution in weakly acidic region to suppress the formation of decavanadate.

S2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. All H atoms in (I.Ca) and (I.Sr) were found from difference Fourier maps, and were refined with restraints; the isotropic displacement parameters were set at 1.5 times of equivalent parameter of the parent atoms. The O—H distance of the water molecules in both crystals was set at ca 0.82 Å. The H atoms in (I.Ca) were uniquely found, but three of four water molecules in (I.Sr) (O1W, O2W and O4W) exhibited three possible positions. The site occupancies of three H atoms on each O atom were refined so as to be 2.0 in total. Each H atom denoted as A has an occupancy close to 1, those denoted B 0.43 (4)–0.51 (4) and those denoted C 0.54 (4)–0.63 (4). This may indicate that in general, one possible combination is H atoms with A and B, and another one is those with A and C.

S3. Results and discussion

In the title calcium and strontium salts, (I.Ca) and (I.Sr), respectively, the glycinate anion coordinates to the vanadium centre as a bidentate N,O-chelating ligand. Two peroxide groups ligate on the equatorial plane of the V atom in the side-on mode. The N atom of the glycinate ligand occupies the remaining position of the equatorial plane. One of the O atoms of the glycinate and one terminal O atom are located at the axial positions. The V atom has thus a distorted penta­gonal bipyramidal geometry (Figs. 1 and 2). Due to the trans influence of terminal atom O1, the V—O(glycinate) bond is very long [2.2780 (8) Å in (I.Ca) and 2.2581 (11) Å in (I.Sr)]. The V atom is displaced by 0.3167 (4) Å in (I.Ca) and by 0.2947 (6) Å in (I.Sr) from the equatorial plane defined by atoms N1, O2, O3, O4 and O5 to the terminal O1 atom. The C1—O6 and C1—O7 bond lengths (Å) and the O6—C1—O7 angles (°) in the glycinate (Tables 2 and 3) indicate the resonancee character of the carboxyl­ate groups.

The crystal packing is quite similar in (I.Ca) and (I.Sr), and that of (I.Ca) is illustrated in Fig. 3. The Ca atom has nine close contacts of 2.3644 (9)–2.6682 (8) Å and the Sr atom has ten close contacts of 2.5682 (11)–2.7176 (11) Å with sorrounding O atoms of the complex anions and water molecules to form a zigzag one-dimensional array of cations. The amine H atoms in the glycinate ligand and water molecules take part in two-dimensional hydrogen-bond networks joined at the complex anion to form, as a whole, a three-dimensional network in both crystals (Tables 4 and 5).

Structure determinations of diperoxovanadate complex with N,O-chelating amino acid are surprisingly limited. A search of the Cambridge Structural Database (CSD, Version 5.34; Allen, 2002) provides four complexes with pyridine-2,4-di­carboxyl­ate (Shaver et al., 1995), pyridine-2-carboxyl­ato-3-oxo­acetate (Shaver et al., 1995), pyridine-2-carboxyl­ate (picolinate; Shaver et al., 1993) and 3-hy­droxy­pyridine-2-carboxyl­ate (3-hy­droxy­picolinate) (Shaver et al., 1993). In all cases, the N-donor atom is located on the equatorial plane of the central metal atom.

As a closely related compound, a dinuclear complex of a peroxovanadate with a zwitterionic (i.e. neutral) glycine ligand, [{VO(O₂)₂}₂(H₃NCH₂COO)]^2-, (II), obtained from a weakly acidic aqueous solution, has been reported (Gabriel et al., 2009) The complex has two vanadium centres bearing two peroxo and one oxo groups on each, and the glycine behaves as a µ₂-O:O ligand. The dimeric peroxovanadate moiety can be derived from [O{VO(O₂)₂}₂]^4- (Svensson et al., 1971), in which V atoms are triply bridged by two peroxo groups and one oxo group, by removing the bridging oxo group to give positions for the coordination of the glycine ligand. The moiety is also related to [V₄O₄(O₂)₈(PO₄)]^7- (Schwendt et al., 1996) and [V₂O₂(O₂)₄(PO₄)]^5- (Schwendt et al., 1994), having so-called Ishii–Venturello and lacunary Ishii–Venturello-type structures, respectively, in which two V atoms are doubly bridged by two η¹,η²-peroxo groups. The structure of (II) can be derived by replacing the phosphate group of the latter with glycine.

The difference in composition of the mono- and dinuclear complexes is mainly due to the pH of preparation. Since vanadium is a good nucleus for NMR, the formation of mono- and dinuclear complexes was examined by ⁵¹V NMR. The ⁵¹V chemical shift of (II) was not given in the literature by Gabriel et al. (2009), and an attempt to get ⁵¹V signals under the conditions of pH 4 to 7, glycine/vanadium 0–4 and H₂O₂/vanadium = 2, indicated that a signal possibly assigned to (II) appeared at -710 p.p.m. at a pH range of 4–6 and glycine/vanadium 1–4. The chemical shift was not sensitive to pH within this pH region. Although the glycine/vanadium ratio in (II) is 1:2, the signal was not very strong at glycine/vanadium = 1, and became larger as the ratio increased. This observation indicates that the stability of the dinuclear complex is not very high. The present mononuclear complex (I) was, however, not observable at such acidic condition, most probably because the protonation of the amino group inhibited the complexation with vanadium. (I) gave a ⁵¹V signal at -754 p.p.m. under the preparative condition before adding Ca²⁺ or Sr²⁺. The complex was stable in comparison with (II), and ca 60% of vanadium was found to be bound to the complex in sodium-free preparative solution (glycine/vanadium = 2), and ca 50% even if the ratio decreased to 1. The chemical shift was not sensitive to pH in the range of pH 7 to 10, but was sensitive to concentration of Na⁺. The signal of (I) moved to -758 p.p.m. and the intensity grew significantly if the sodium concentration was raised from 0.15 M of the preparative solution to 1.0 M. This may indicate strong electrostatic inter­action between sodium cation and the complex anion in the solution. The higher solubility of both salts in NaCl solution (50 mg of (I.Ca) and 30 mg of (I.Sr) in 5 ml of 0.30 M NaCl aqueous solution) than in water (25 mg of (I.Ca) and 20 mg of (I.Sr) in 5 ml of ion-exchanged distilled water) may support this ionic inter­action. Such effect was also observed when chemicals of Ca or Sr was added in the preparation process, and the signal of (I) moved to ca -764 p.p.m. The aqueous solution of the crystals showed three signals at ca -626, -762 and -768 p.p.m., most probably assigned to glycinate-free monoperoxomonovanadate, (I), and glycinate-free diperoxomonovanadate, respectively, indicating the dissociation of the complex (Andersson et al., 2000). The intensity ratio of signals at ca -762 p.p.m. to that at ca -768 p.p.m. was about 1.7; the intensity of the signal at ca -626 p.p.m. was less than 10% of the sum of the other two. When the crystals were dissolved in 1.0 M NaCl solution the signal at ca -768 p.p.m. moved downfield and overlapped with the signal of the present complex at -764 p.p.m.

Related literature

For related literature, see: Andersson et al. (2000); Gabriel et al. (2009); Rehder (2008); Schwendt et al. (1994, 1996); Shaver et al. (1993, 1995); Svensson & Stomberg (1971).

Computing details

For both compounds, data collection: CrystalClear (Rigaku, 2008); cell refinement: CrystalClear (Rigaku, 2008); data reduction: CrystalClear (Rigaku, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The structure of the Ca salt, (I.Ca). Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonds are shown with dotted lines. [Symmetry codes: (i) x+1, -y+1/2, z+1/2; (ii) x, -y+1/2, z-1/2; (iii) -x+1, -y+1, -z; (iv) -x+1, y+1/2, -z+1/2; (v) -x+1, y-1/2, -z+1/2; (vi) x, -y+1/2, z+1/2; (vii) -x+1, -y+1, -z+1; (viii) -x, -y+1, -z.]
	Fig. 2. Structure of the Sr salt, (I.Sr). Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonds are shown with dotted lines. [Symmetry codes: (i) x, -y+1/2, z-1/2; (ii) -x+1, -y+1, -z; (iii) -x+1, y+1/2, -z+1/2; (iv) -x+1, y-1/2, -z+1/2; (v) x, -y+1/2, z+1/2; (vi) -x+1, -y+1, -z+1; (vii) -x, -y+1, -z.]
	Fig. 3. Packing diagram of (I.Ca). with displacement ellipsoids drawn at the 50% probability level. Hydrogen bonds are shown with dotted lines.

(I.Ca) Calcium (glycinato-κ²N,O)oxidobis(peroxido-κ²O,O')vanadate(V) tetrahydrate

Crystal data

Ca[V(C2H4NO2)(O2)O]]·4H2O	F(000) = 648
Mr = 317.15	Dx = 2.038 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybc	Cell parameters from 3954 reflections
a = 9.079 (2) Å	θ = 3.1–30.0°
b = 8.564 (2) Å	µ = 1.51 mm^−1
c = 13.833 (4) Å	T = 93 K
β = 106.016 (3)°	Prism, yellow
V = 1033.8 (4) Å^3	0.20 × 0.18 × 0.17 mm
Z = 4

Data collection

Rigaku Saturn724+ (4x4 bin mode) diffractometer	2951 independent reflections
Radiation source: fine-focus rotating anode	2833 reflections with I > 2σ(I)
Confocal monochromator	Rint = 0.021
Detector resolution: 28.5714 pixels mm^-1	θmax = 30.0°, θmin = 3.1°
CCD scans	h = −10→12
Absorption correction: numerical (CrystalClear; Rigaku, 2008)	k = −9→11
Tmin = 0.810, Tmax = 0.880	l = −19→19
9037 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.018	Hydrogen site location: difference Fourier map
wR(F^2) = 0.048	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0239P)^2 + 0.4294P] where P = (Fo^2 + 2Fc^2)/3
2951 reflections	(Δ/σ)max = 0.001
181 parameters	Δρmax = 0.49 e Å^−3
8 restraints	Δρmin = −0.34 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.

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. All hydrogen atoms were found out from dfferential Fourier maps. The cordinates of H atoms were refined freely, and U_iso's were restrained to 1.5 times of the U_eq of the atom bound.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
V1	0.267405 (17)	0.489347 (18)	0.099419 (11)	0.00567 (5)
O1	0.20021 (8)	0.66573 (8)	0.08533 (5)	0.00964 (13)
O2	0.37775 (8)	0.51498 (8)	0.24168 (5)	0.00899 (13)
O3	0.47413 (8)	0.53106 (8)	0.17149 (5)	0.00869 (12)
O4	0.32714 (8)	0.45143 (9)	−0.01875 (5)	0.01003 (13)
O5	0.17011 (8)	0.39934 (8)	−0.02766 (5)	0.01000 (13)
O6	0.34102 (8)	0.23980 (8)	0.14585 (5)	0.00841 (12)
O7	0.24413 (8)	−0.00095 (8)	0.14566 (5)	0.00983 (13)
C1	0.23216 (10)	0.14522 (11)	0.14178 (6)	0.00761 (16)
C2	0.07380 (10)	0.21597 (11)	0.12833 (7)	0.00959 (16)
H1A	0.0113 (17)	0.1927 (17)	0.0618 (11)	0.014*
H1B	0.0255 (17)	0.1675 (17)	0.1747 (11)	0.014*
N1	0.08323 (9)	0.38744 (10)	0.14280 (6)	0.00861 (14)
H2A	0.0030 (17)	0.4294 (18)	0.1083 (11)	0.013*
H2B	0.0904 (16)	0.4069 (17)	0.2043 (11)	0.013*
Ca1	0.57064 (2)	0.29995 (2)	0.276193 (13)	0.00694 (5)
O1W	0.47354 (9)	0.31087 (9)	0.41820 (6)	0.01328 (14)
HW1A	0.4205 (17)	0.3817 (18)	0.4257 (12)	0.020*
HW1B	0.4439 (18)	0.2364 (17)	0.4420 (12)	0.020*
O2W	0.72250 (9)	0.30843 (9)	0.16223 (6)	0.01322 (14)
HW2A	0.7216 (19)	0.2264 (17)	0.1333 (11)	0.020*
HW2B	0.7028 (18)	0.3774 (17)	0.1241 (11)	0.020*
O3W	0.95780 (9)	0.64679 (9)	0.65051 (6)	0.01458 (14)
HW3A	0.9318 (19)	0.7264 (17)	0.6175 (12)	0.022*
HW3B	1.0428 (16)	0.6240 (19)	0.6510 (12)	0.022*
O4W	0.72534 (9)	0.46100 (9)	0.56158 (6)	0.01408 (14)
HW4A	0.8052 (17)	0.5155 (17)	0.5836 (13)	0.021*
HW4B	0.7092 (19)	0.4449 (19)	0.5028 (10)	0.021*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
V1	0.00610 (8)	0.00428 (8)	0.00623 (8)	0.00011 (5)	0.00102 (5)	−0.00002 (5)
O1	0.0096 (3)	0.0072 (3)	0.0114 (3)	0.0009 (2)	0.0017 (2)	0.0001 (2)
O2	0.0101 (3)	0.0100 (3)	0.0073 (3)	−0.0002 (2)	0.0032 (2)	0.0001 (2)
O3	0.0074 (3)	0.0096 (3)	0.0092 (3)	−0.0008 (2)	0.0023 (2)	0.0003 (2)
O4	0.0096 (3)	0.0109 (3)	0.0103 (3)	−0.0018 (2)	0.0039 (2)	−0.0011 (2)
O5	0.0086 (3)	0.0112 (3)	0.0094 (3)	−0.0027 (2)	0.0012 (2)	−0.0020 (2)
O6	0.0077 (3)	0.0063 (3)	0.0103 (3)	−0.0005 (2)	0.0010 (2)	−0.0001 (2)
O7	0.0105 (3)	0.0055 (3)	0.0124 (3)	0.0001 (2)	0.0014 (2)	0.0001 (2)
C1	0.0088 (4)	0.0079 (4)	0.0054 (3)	0.0000 (3)	0.0007 (3)	0.0000 (3)
C2	0.0082 (4)	0.0065 (4)	0.0139 (4)	−0.0007 (3)	0.0027 (3)	0.0003 (3)
N1	0.0079 (3)	0.0070 (4)	0.0107 (3)	0.0013 (3)	0.0023 (3)	0.0008 (3)
Ca1	0.00694 (8)	0.00515 (9)	0.00816 (8)	−0.00004 (6)	0.00113 (6)	0.00061 (5)
O1W	0.0169 (3)	0.0088 (3)	0.0171 (3)	0.0023 (3)	0.0097 (3)	0.0024 (3)
O2W	0.0170 (3)	0.0092 (4)	0.0154 (3)	0.0023 (3)	0.0078 (3)	0.0024 (3)
O3W	0.0118 (3)	0.0148 (4)	0.0174 (3)	0.0016 (3)	0.0044 (3)	0.0056 (3)
O4W	0.0150 (3)	0.0143 (4)	0.0127 (3)	−0.0005 (3)	0.0035 (3)	−0.0018 (3)

Geometric parameters (Å, º)

V1—O1	1.6206 (8)	N1—H2B	0.852 (15)
V1—O4	1.8870 (8)	Ca1—O2	2.4949 (8)
V1—O5	1.8994 (8)	Ca1—O3	2.4663 (8)
V1—O3	1.9004 (8)	Ca1—O6	2.4059 (8)
V1—O2	1.9587 (8)	Ca1—O2W	2.3644 (9)
V1—N1	2.1146 (9)	Ca1—O1W	2.3665 (9)
V1—O6	2.2780 (8)	Ca1—O7^i	2.4291 (8)
O2—O3	1.4819 (10)	Ca1—O3^ii	2.4807 (9)
O2—Ca1^i	2.5101 (9)	Ca1—O2^ii	2.5101 (9)
O3—Ca1^i	2.4807 (9)	Ca1—O1^ii	2.6682 (8)
O4—O5	1.4663 (10)	O1W—HW1A	0.799 (13)
C1—O6	1.2671 (11)	O1W—HW1B	0.798 (13)
C1—O7	1.2564 (12)	O2W—HW2A	0.807 (13)
O7—Ca1^ii	2.4291 (8)	O2W—HW2B	0.779 (13)
C1—C2	1.5236 (13)	O3W—HW3A	0.819 (13)
C2—N1	1.4814 (13)	O3W—HW3B	0.794 (13)
C2—H1A	0.959 (15)	O4W—HW4A	0.845 (14)
C2—H1B	0.966 (15)	O4W—HW4B	0.798 (13)
N1—H2A	0.834 (15)
O1—V1—O4	104.18 (3)	C2—N1—H2A	109.9 (10)
O1—V1—O5	101.74 (3)	V1—N1—H2A	107.1 (10)
O4—V1—O5	45.57 (3)	C2—N1—H2B	108.3 (10)
O1—V1—O3	99.92 (3)	V1—N1—H2B	110.8 (10)
O4—V1—O3	90.49 (3)	H2A—N1—H2B	107.6 (14)
O5—V1—O3	134.56 (3)	O2W—Ca1—O1W	166.29 (3)
O1—V1—O2	95.02 (3)	O2W—Ca1—O6	92.92 (3)
O4—V1—O2	134.43 (3)	O1W—Ca1—O6	100.74 (3)
O5—V1—O2	162.49 (3)	O2W—Ca1—O7^i	79.38 (3)
O3—V1—O2	45.13 (3)	O1W—Ca1—O7^i	88.49 (3)
O1—V1—N1	96.77 (4)	O6—Ca1—O7^i	146.53 (2)
O4—V1—N1	127.85 (3)	O2W—Ca1—O3	76.22 (3)
O5—V1—N1	83.85 (3)	O1W—Ca1—O3	107.60 (3)
O3—V1—N1	132.26 (3)	O6—Ca1—O3	68.76 (3)
O2—V1—N1	89.22 (3)	O7^i—Ca1—O3	77.77 (3)
O1—V1—O6	168.45 (3)	O2W—Ca1—O3^ii	113.30 (3)
O4—V1—O6	87.17 (3)	O1W—Ca1—O3^ii	70.49 (3)
O5—V1—O6	84.58 (3)	O6—Ca1—O3^ii	80.91 (2)
O3—V1—O6	81.84 (3)	O7^i—Ca1—O3^ii	132.13 (3)
O2—V1—O6	78.05 (3)	O3—Ca1—O3^ii	148.870 (13)
N1—V1—O6	74.12 (3)	O2W—Ca1—O2	110.94 (3)
V1—O1—Ca1^i	97.02 (3)	O1W—Ca1—O2	74.16 (3)
O3—O2—V1	65.35 (4)	O6—Ca1—O2	66.25 (3)
O3—O2—Ca1	71.57 (4)	O7^i—Ca1—O2	86.00 (3)
V1—O2—Ca1	104.30 (3)	O3—Ca1—O2	34.75 (2)
O3—O2—Ca1^i	71.65 (4)	O3^ii—Ca1—O2	125.32 (3)
V1—O2—Ca1^i	93.88 (3)	O2W—Ca1—O2^ii	78.76 (3)
Ca1—O2—Ca1^i	126.60 (3)	O1W—Ca1—O2^ii	104.04 (3)
O2—O3—V1	69.52 (4)	O6—Ca1—O2^ii	82.22 (2)
O2—O3—Ca1	73.68 (4)	O7^i—Ca1—O2^ii	126.95 (3)
V1—O3—Ca1	107.26 (3)	O3—Ca1—O2^ii	140.19 (3)
O2—O3—Ca1^i	73.81 (4)	O3^ii—Ca1—O2^ii	34.54 (2)
V1—O3—Ca1^i	96.31 (3)	O2—Ca1—O2^ii	147.038 (16)
Ca1—O3—Ca1^i	129.34 (3)	O2W—Ca1—O1^ii	90.53 (3)
O5—O4—V1	67.66 (4)	O1W—Ca1—O1^ii	79.42 (3)
O4—O5—V1	66.77 (4)	O6—Ca1—O1^ii	142.05 (3)
C1—O6—V1	115.00 (6)	O7^i—Ca1—O1^ii	71.10 (3)
C1—O6—Ca1	132.39 (6)	O3—Ca1—O1^ii	147.95 (2)
V1—O6—Ca1	97.85 (3)	O3^ii—Ca1—O1^ii	63.17 (2)
C1—O7—Ca1^ii	139.42 (6)	O2—Ca1—O1^ii	145.33 (2)
O7—C1—O6	125.30 (9)	O2^ii—Ca1—O1^ii	61.45 (2)
O7—C1—C2	117.97 (8)	Ca1—O1W—HW1A	120.9 (12)
O6—C1—C2	116.71 (8)	Ca1—O1W—HW1B	123.8 (12)
N1—C2—C1	111.12 (8)	HW1A—O1W—HW1B	105.6 (16)
N1—C2—H1A	109.4 (9)	Ca1—O2W—HW2A	112.0 (11)
C1—C2—H1A	108.8 (9)	Ca1—O2W—HW2B	114.0 (12)
N1—C2—H1B	110.9 (9)	HW2A—O2W—HW2B	110.8 (16)
C1—C2—H1B	109.5 (9)	HW3A—O3W—HW3B	109.8 (16)
H1A—C2—H1B	106.9 (12)	HW4A—O4W—HW4B	111.1 (17)
C2—N1—V1	113.05 (6)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H2A···O5^iii	0.834 (15)	2.213 (15)	3.0232 (11)	163.8 (14)
N1—H2B···O3W^iv	0.852 (15)	2.218 (15)	2.9979 (14)	152.2 (13)
O1W—HW1A···O4W^iv	0.80 (1)	1.93 (1)	2.7266 (12)	174 (2)
O1W—HW1B···O4^v	0.80 (1)	2.08 (1)	2.8659 (11)	169 (2)
O2W—HW2A···O4W^vi	0.81 (1)	1.89 (1)	2.6987 (12)	177 (2)
O2W—HW2B···O4^vii	0.78 (1)	2.03 (1)	2.8069 (12)	173 (2)
O3W—HW3A···O5^i	0.82 (1)	1.99 (1)	2.7974 (11)	169 (2)
O3W—HW3B···O7^viii	0.79 (1)	2.13 (1)	2.9014 (12)	164 (2)
O4W—HW4A···O3W	0.85 (1)	1.83 (1)	2.6583 (12)	168 (2)
O4W—HW4B···O7^i	0.80 (1)	2.26 (1)	2.9732 (13)	150 (2)

Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (iii) −x, −y+1, −z; (iv) −x+1, −y+1, −z+1; (v) x, −y+1/2, z+1/2; (vi) x, −y+1/2, z−1/2; (vii) −x+1, −y+1, −z; (viii) x+1, −y+1/2, z+1/2.

(I.Sr) Calcium (glycinato-κ²N,O)oxidobis(peroxido-κ²O,O')vanadate(V) tetrahydrate

Crystal data

Ca[V(C2H4NO2)(O2)O]]·4H2O	F(000) = 720
Mr = 364.69	Dx = 2.330 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71069 Å
Hall symbol: -P 2ybc	Cell parameters from 3970 reflections
a = 10.156 (3) Å	θ = 2.9–30.0°
b = 8.851 (2) Å	µ = 6.08 mm^−1
c = 12.549 (3) Å	T = 93 K
β = 112.818 (3)°	Prism, yellow
V = 1039.8 (5) Å^3	0.15 × 0.10 × 0.07 mm
Z = 4

Data collection

Rigaku Saturn724+ (4x4 bin mode) diffractometer	2986 independent reflections
Radiation source: fine-focus rotating anode	2793 reflections with I > 2σ(I)
Confocal monochromator	Rint = 0.027
Detector resolution: 28.5714 pixels mm^-1	θmax = 30.0°, θmin = 2.9°
CCD scans	h = −13→14
Absorption correction: numerical (CrystalClear; Rigaku, 2008)	k = −11→11
Tmin = 0.593, Tmax = 0.732	l = −17→17
9315 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.019	Hydrogen site location: difference Fourier map
wR(F^2) = 0.046	H atoms treated by a mixture of independent and constrained refinement
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0226P)^2 + 0.3748P] where P = (Fo^2 + 2Fc^2)/3
2986 reflections	(Δ/σ)max = 0.001
199 parameters	Δρmax = 0.63 e Å^−3
14 restraints	Δρmin = −0.37 e Å^−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. All H atoms were found out from differential Fourier maps. Atomic coordinates of H atoms were refined freely, and U_iso's were restrained to 1.5 times of the U_eq of the atom bound. Disorder of H atoms in three positions on O1W, O2W and O4W was observed. The site occupancy factors of these H atoms were refined as free variables, so as to fix the sum of occupancies of three H atoms on one water molecule to 2.0 by SUMP command.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
V1	0.24989 (2)	0.49391 (3)	0.093694 (19)	0.00740 (6)
O1	0.18438 (11)	0.66348 (11)	0.06781 (9)	0.0111 (2)
O2	0.39394 (11)	0.54067 (12)	0.24614 (9)	0.0109 (2)
O3	0.44753 (11)	0.53725 (12)	0.15195 (9)	0.0108 (2)
O4	0.25648 (11)	0.43646 (12)	−0.04923 (9)	0.0116 (2)
O5	0.12318 (11)	0.38945 (12)	−0.04052 (9)	0.0110 (2)
O6	0.32402 (10)	0.25811 (12)	0.15772 (9)	0.01015 (19)
O7	0.23392 (11)	0.03311 (11)	0.17740 (9)	0.0113 (2)
C1	0.22772 (15)	0.17372 (16)	0.16760 (12)	0.0090 (3)
C2	0.09417 (15)	0.25168 (17)	0.16661 (13)	0.0109 (3)
H1A	0.017 (2)	0.225 (2)	0.0963 (18)	0.016*
H1B	0.073 (2)	0.215 (2)	0.2314 (19)	0.016*
N1	0.11095 (13)	0.41771 (15)	0.17087 (11)	0.0103 (2)
H2A	0.028 (2)	0.459 (2)	0.1391 (18)	0.015*
H2B	0.144 (2)	0.453 (2)	0.2423 (18)	0.015*
Sr1	0.579673 (13)	0.327149 (14)	0.307253 (10)	0.00733 (4)
O1W	0.43161 (13)	0.29344 (15)	0.44303 (11)	0.0150 (2)
HW1A	0.374 (2)	0.226 (2)	0.438 (2)	0.023*	0.95 (4)
HW1B	0.400 (4)	0.374 (3)	0.451 (4)	0.023*	0.51 (4)
HW1C	0.502 (3)	0.274 (5)	0.501 (2)	0.023*	0.54 (4)
O2W	0.67378 (16)	0.30239 (15)	0.14350 (11)	0.0200 (3)
HW2A	0.707 (3)	0.380 (2)	0.131 (2)	0.030*	0.94 (4)
HW2B	0.591 (3)	0.287 (6)	0.098 (4)	0.030*	0.43 (4)
HW2C	0.718 (4)	0.231 (3)	0.135 (3)	0.030*	0.63 (4)
O3W	0.95799 (12)	0.58997 (14)	0.61216 (10)	0.0156 (2)
HW3A	1.0375 (17)	0.564 (2)	0.6300 (19)	0.023*
HW3B	0.945 (2)	0.6787 (18)	0.590 (2)	0.023*
O4W	0.70203 (13)	0.44509 (13)	0.52191 (10)	0.0137 (2)
HW4A	0.7823 (18)	0.482 (2)	0.5422 (19)	0.020*	0.93 (4)
HW4B	0.713 (5)	0.375 (4)	0.567 (3)	0.020*	0.45 (4)
HW4C	0.655 (3)	0.514 (3)	0.533 (3)	0.020*	0.61 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
V1	0.00699 (11)	0.00592 (11)	0.00846 (10)	0.00008 (8)	0.00208 (8)	0.00038 (8)
O1	0.0091 (5)	0.0089 (5)	0.0131 (5)	−0.0002 (4)	0.0019 (4)	0.0001 (4)
O2	0.0109 (5)	0.0115 (5)	0.0098 (4)	−0.0001 (4)	0.0035 (4)	−0.0008 (4)
O3	0.0094 (4)	0.0108 (5)	0.0120 (5)	−0.0008 (4)	0.0039 (4)	−0.0002 (4)
O4	0.0111 (5)	0.0126 (5)	0.0125 (5)	−0.0027 (4)	0.0060 (4)	−0.0010 (4)
O5	0.0090 (4)	0.0118 (5)	0.0121 (5)	−0.0023 (4)	0.0038 (4)	−0.0015 (4)
O6	0.0087 (4)	0.0079 (5)	0.0125 (5)	−0.0003 (4)	0.0026 (4)	0.0007 (4)
O7	0.0115 (5)	0.0075 (5)	0.0142 (5)	0.0004 (4)	0.0043 (4)	0.0004 (4)
C1	0.0085 (6)	0.0103 (7)	0.0068 (5)	0.0011 (5)	0.0015 (5)	−0.0003 (5)
C2	0.0109 (6)	0.0092 (7)	0.0137 (6)	0.0012 (5)	0.0058 (5)	0.0012 (5)
N1	0.0108 (5)	0.0096 (6)	0.0114 (5)	0.0022 (5)	0.0054 (4)	0.0005 (4)
Sr1	0.00712 (7)	0.00594 (7)	0.00846 (6)	0.00035 (4)	0.00250 (5)	0.00048 (4)
O1W	0.0154 (5)	0.0125 (5)	0.0207 (6)	−0.0001 (5)	0.0109 (5)	0.0018 (4)
O2W	0.0354 (8)	0.0102 (6)	0.0237 (6)	−0.0046 (5)	0.0214 (6)	−0.0030 (5)
O3W	0.0133 (5)	0.0126 (5)	0.0211 (5)	0.0019 (4)	0.0069 (4)	0.0031 (4)
O4W	0.0148 (5)	0.0113 (5)	0.0165 (5)	−0.0013 (4)	0.0078 (4)	−0.0004 (4)

Geometric parameters (Å, º)

V1—O1	1.6227 (11)	Sr1—O2	2.5683 (11)
V1—O3	1.8901 (12)	Sr1—O3	2.6511 (11)
V1—O4	1.8902 (11)	Sr1—O6	2.6186 (12)
V1—O5	1.9147 (11)	Sr1—O7^i	2.5810 (11)
V1—O2	1.9495 (11)	Sr1—O2W	2.5899 (13)
V1—N1	2.1080 (13)	Sr1—O3^ii	2.6518 (12)
V1—O6	2.2581 (11)	Sr1—O2^ii	2.6626 (12)
O1—Sr1^i	2.7176 (11)	Sr1—O1W	2.6908 (13)
O2—O3	1.4809 (15)	Sr1—O4W	2.7007 (12)
O2—Sr1^i	2.6626 (12)	Sr1—O1^ii	2.7175 (11)
O3—Sr1^i	2.6518 (12)	O1W—HW1A	0.817 (16)
O4—O5	1.4602 (14)	O1W—HW1B	0.809 (19)
O6—C1	1.2743 (17)	O1W—HW1C	0.816 (19)
O7—C1	1.2498 (17)	O2W—HW2A	0.807 (17)
O7—Sr1^ii	2.5810 (11)	O2W—HW2B	0.82 (2)
C1—C2	1.518 (2)	O2W—HW2C	0.810 (19)
C2—N1	1.478 (2)	O3W—HW3A	0.784 (15)
C2—H1A	0.96 (2)	O3W—HW3B	0.825 (15)
C2—H1B	0.97 (2)	O4W—HW4A	0.822 (16)
N1—H2A	0.86 (2)	O4W—HW4B	0.818 (19)
N1—H2B	0.88 (2)	O4W—HW4C	0.816 (18)
O1—V1—O3	100.44 (5)	O2W—Sr1—O6	88.86 (5)
O1—V1—O4	102.80 (5)	O2—Sr1—O3	32.92 (3)
O3—V1—O4	89.92 (5)	O7^i—Sr1—O3	72.96 (4)
O1—V1—O5	100.78 (5)	O2W—Sr1—O3	73.35 (4)
O3—V1—O5	133.54 (5)	O6—Sr1—O3	63.79 (3)
O4—V1—O5	45.13 (4)	O2—Sr1—O3^ii	130.56 (4)
O1—V1—O2	95.36 (5)	O7^i—Sr1—O3^ii	142.88 (3)
O3—V1—O2	45.34 (4)	O2W—Sr1—O3^ii	99.75 (4)
O4—V1—O2	134.34 (5)	O6—Sr1—O3^ii	76.35 (3)
O5—V1—O2	163.38 (5)	O3—Sr1—O3^ii	139.44 (2)
O1—V1—N1	95.30 (5)	O2—Sr1—O2^ii	139.427 (18)
O3—V1—N1	133.38 (5)	O7^i—Sr1—O2^ii	123.29 (3)
O4—V1—N1	128.77 (5)	O2W—Sr1—O2^ii	67.39 (4)
O5—V1—N1	84.74 (5)	O6—Sr1—O2^ii	76.47 (3)
O2—V1—N1	89.91 (5)	O3—Sr1—O2^ii	123.69 (3)
O1—V1—O6	168.62 (5)	O3^ii—Sr1—O2^ii	32.36 (3)
O3—V1—O6	83.82 (4)	O2—Sr1—O1W	75.20 (4)
O4—V1—O6	87.67 (4)	O7^i—Sr1—O1W	127.22 (4)
O5—V1—O6	83.36 (4)	O2W—Sr1—O1W	164.12 (4)
O2—V1—O6	80.05 (4)	O6—Sr1—O1W	77.62 (4)
N1—V1—O6	74.40 (5)	O3—Sr1—O1W	107.18 (4)
V1—O1—Sr1^i	100.15 (5)	O3^ii—Sr1—O1W	69.20 (4)
O3—O2—V1	65.21 (6)	O2^ii—Sr1—O1W	100.91 (4)
O3—O2—Sr1	76.62 (6)	O2—Sr1—O4W	90.80 (4)
V1—O2—Sr1	108.76 (5)	O7^i—Sr1—O4W	67.18 (3)
O3—O2—Sr1^i	73.42 (6)	O2W—Sr1—O4W	130.96 (4)
V1—O2—Sr1^i	93.77 (4)	O6—Sr1—O4W	138.57 (3)
Sr1—O2—Sr1^i	129.94 (4)	O3—Sr1—O4W	111.59 (4)
O2—O3—V1	69.45 (6)	O3^ii—Sr1—O4W	102.92 (4)
O2—O3—Sr1	70.47 (6)	O2^ii—Sr1—O4W	124.53 (3)
V1—O3—Sr1	107.51 (5)	O1W—Sr1—O4W	64.23 (4)
O2—O3—Sr1^i	74.22 (6)	O2—Sr1—O1^ii	161.04 (3)
V1—O3—Sr1^i	95.54 (4)	O7^i—Sr1—O1^ii	82.89 (4)
Sr1—O3—Sr1^i	126.71 (4)	O2W—Sr1—O1^ii	84.17 (4)
O5—O4—V1	68.33 (6)	O6—Sr1—O1^ii	134.14 (3)
O4—O5—V1	66.54 (6)	O3—Sr1—O1^ii	151.61 (3)
C1—O6—V1	114.44 (9)	O3^ii—Sr1—O1^ii	60.49 (3)
C1—O6—Sr1	130.71 (9)	O2^ii—Sr1—O1^ii	59.02 (3)
V1—O6—Sr1	98.07 (4)	O1W—Sr1—O1^ii	99.20 (4)
C1—O7—Sr1^ii	135.90 (9)	O4W—Sr1—O1^ii	70.66 (4)
O7—C1—O6	125.59 (13)	Sr1—O1W—HW1A	126.1 (17)
O7—C1—C2	117.67 (13)	Sr1—O1W—HW1B	109 (3)
O6—C1—C2	116.74 (12)	HW1A—O1W—HW1B	110 (3)
N1—C2—C1	111.20 (11)	Sr1—O1W—HW1C	95 (3)
N1—C2—H1A	108.6 (12)	HW1A—O1W—HW1C	105 (3)
C1—C2—H1A	108.0 (12)	HW1B—O1W—HW1C	109 (4)
N1—C2—H1B	111.2 (12)	Sr1—O2W—HW2A	113.2 (18)
C1—C2—H1B	109.0 (12)	Sr1—O2W—HW2B	89 (4)
H1A—C2—H1B	108.8 (17)	HW2A—O2W—HW2B	113 (4)
C2—N1—V1	112.95 (9)	Sr1—O2W—HW2C	125 (3)
C2—N1—H2A	109.1 (13)	HW2A—O2W—HW2C	110 (3)
V1—N1—H2A	111.1 (13)	HW2B—O2W—HW2C	104 (5)
C2—N1—H2B	112.2 (13)	HW3A—O3W—HW3B	113 (2)
V1—N1—H2B	107.3 (13)	Sr1—O4W—HW4A	118.8 (16)
H2A—N1—H2B	103.8 (18)	Sr1—O4W—HW4B	106 (3)
O2—Sr1—O7^i	86.28 (4)	HW4A—O4W—HW4B	103 (4)
O2—Sr1—O2W	106.24 (4)	Sr1—O4W—HW4C	112 (2)
O7^i—Sr1—O2W	68.49 (4)	HW4A—O4W—HW4C	103 (3)
O2—Sr1—O6	63.15 (4)	HW4B—O4W—HW4C	113 (4)
O7^i—Sr1—O6	135.48 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H2A···O5^iii	0.86 (2)	2.05 (2)	2.8682 (17)	157.8 (18)
O1W—HW1A···O4^iv	0.82 (2)	1.92 (2)	2.7291 (17)	171 (2)
O2W—HW2A···O4^v	0.81 (2)	2.03 (2)	2.8097 (17)	162 (2)
O4W—HW4A···O3W	0.82 (2)	1.91 (2)	2.7205 (17)	168 (2)
O1W—HW1B···O4W^vi	0.81 (2)	2.00 (2)	2.8026 (18)	171 (4)
O2W—HW2B···O1W^vii	0.82 (2)	2.11 (3)	2.881 (2)	155 (5)
O3W—HW3B···O5^i	0.83 (2)	2.00 (2)	2.8177 (17)	169 (2)
O4W—HW4B···O2W^iv	0.82 (2)	1.96 (2)	2.7473 (18)	161 (5)
O1W—HW1C···O2W^iv	0.82 (2)	2.07 (2)	2.881 (2)	173 (4)
O2W—HW2C···O4W^vii	0.81 (2)	2.07 (3)	2.7473 (18)	141 (4)
O4W—HW4C···O1W^vi	0.82 (2)	2.00 (2)	2.8026 (18)	170 (3)

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