A monoclinic polymorph of di-μ-oxido-bis­({2-[2-(methyl­amino)ethyl­imino­methyl]phenolato-κ3 N,N′,O}oxidovanadium(V))

Grzegorz Romanowski; Michał Wera; Artur Sikorski

doi:10.1107/S160053680803328X

. 2008 Nov 13;64(Pt 12):m1548–m1549. doi: 10.1107/S160053680803328X

A monoclinic polymorph of di-μ-oxido-bis({2-[2-(methylamino)ethyliminomethyl]phenolato-κ³ N,N′,O}oxidovanadium(V))

Grzegorz Romanowski ^a,^*, Michał Wera ^a, Artur Sikorski ^a

PMCID: PMC2959960 PMID: 21581160

Abstract

A new monoclinic polymorph of the title compound, [V₂(C₁₀H₁₃N₂O)₂O₄], which is a centrosymmetric dimer, crystallizes in space group P2₁/c, whereas the previously known polymorph crystallizes in the orthorhombic space group Pbca [Mokry & Carrano (1993 ▶). Inorg. Chem. 32, 6119–6121]. Each V^V atom is six-coordinated by one oxide group, two N atoms and one O atom from the Schiff base ligand, and by two additional bridging O atoms. The two methylene groups are each disordered over two sites, with occupancy factors of 0.776 (14) and 0.224 (14). In the crystal structure, there are C—H⋯O hydrogen bonds and C—H⋯π interactions between the dimers.

Related literature

For general background, see: Butler & Walker (1993 ▶); Carter-Franklin et al. (2003 ▶); Eady (2003 ▶); Evangelou (2002 ▶); Mendz (1991 ▶); Rehder et al. (2003 ▶); Sakurai (2002 ▶). For related structures, see: Mokry & Carrano (1993 ▶); Rao et al. (1981 ▶); Romanowski et al. (2008 ▶); Root et al. (1993 ▶). For the synthesis, see: Kwiatkowski et al. (2003 ▶).

Experimental

Crystal data

[V₂(C₁₀H₁₃N₂O)₂O₄]
M _r = 520.33
Monoclinic,
a = 6.6801 (2) Å
b = 11.9955 (6) Å
c = 13.8643 (7) Å
β = 92.156 (4)°
V = 1110.18 (9) Å³
Z = 2
Mo Kα radiation
μ = 0.89 mm⁻¹
T = 295 (2) K
0.6 × 0.1 × 0.1 mm

Data collection

Oxford Diffraction Ruby CCD diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2006 ▶) T _min = 0.532, T _max = 0.915
6336 measured reflections
1960 independent reflections
1288 reflections with I > 2σ(I)
R _int = 0.050

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.106
S = 0.90
1960 reflections
155 parameters
H-atom parameters constrained
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2006 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2006 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPII (Johnson, 1976 ▶); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680803328X/hy2159sup1.cif

e-64-m1548-sup1.cif^{(19.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680803328X/hy2159Isup2.hkl

e-64-m1548-Isup2.hkl^{(96.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

O7—V14	1.926 (2)
N9—V14	2.158 (3)
N12—V14	2.146 (3)
V14—O16	1.612 (2)
V14—O15	1.674 (2)
V14—O15ⁱ	2.316 (2)

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Symmetry code: (i) Inline graphic .

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C8—H8A⋯O16ⁱⁱ	0.93	2.60	3.520 (4)	170
C11B—H11C⋯Cg1ⁱⁱⁱⁱⁱⁱ	0.97	2.82	3.47 (2)	124

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Symmetry codes: (ii) Inline graphic ; (iii) . Cg1 is the centroid of the C1–C6 ring.

Acknowledgments

The Polish Ministry of Science and Higher Education under grants BW/8000-5-0462-8 and DS/8210-40-086-8 financially supported this work.

supplementary crystallographic information

Comment

In the past few decades, the interest in the coordination chemistry and biochemistry of vanadium compounds has increased due to their influence on biological systems, viz. in diabetes mellitus (Sakurai, 2002) and cancer treatment (Evangelou, 2002). Moreover, vanadium activity has been discovered in the inhibitory and promotory processes like nitrogenases (Eady, 2003), haloperoxidases (Butler & Walker, 1993; Carter-Franklin et al., 2003; Rehder et al., 2003), mutases and isomerases (Mendz, 1991).

The structure of the title compound was first reported in orthorhombic space group Pbca (Mokry & Carrano, 1993). Here we report the synthesis and structure of a new polymorph of the compound in space group P2₁/c. We have described earlier the spectroscopic properties (IR, UV-Vis, ¹H and ⁵¹V NMR) of this compound (Kwiatkowski et al., 2003). The half of the molecule, constituting the asymmetric unit of the structure, is related to the other half by a center of symmetry. Each V^V atom is six-coordinated by two strongly (O15, O16) and one weakly (O15ⁱ) associated oxide groups and by the tridentate Schiff base ligand, viz. a phenolate O atom (O7), a secondary amine N atom (N12), both occupying the axial positions, and an imine N atom (N9) (Fig. 1). The geometry about the V atom is distorted octahedral. The V14 ═O16 bond length of 1.612 (2) Å (Table 1) compares well with the distances between V and the doubly bonded O atoms (Romanowski et al., 2008; Root et al., 1993). The V14, O15, V14ⁱ, O15ⁱ atoms are situated at vertices of a parallelogram with the acute O15—V14—O15ⁱ angle of 78.64 (8)° [symmetry code: (i) -x, -y+2, -z]. The five-membered ring comprising the ethylenediamine moiety exhibits twofold disorder. The C10 and C11 atoms are disordered over two sites, with occupancy factors of 0.776 (14) and 0.224 (14) for C10A/C11A and C10B/C11B, respectively. The five-membered chelate ring defined by V14, N9, C10A, C11A, N12 adopts an envelope conformation on C10A, with P = 244.0 (3)° and τ₍_M₎ = 54.9 (4)° for reference bond V14—N9 (Rao et al., 1981) and the ring formed by V14, N9, C10B, C11B, N12 takes the envelope conformation on C11B, with P = 81.8 (7)° and τ₍_M₎ = 62.3 (9)° for reference bond V14—N9 (Fig. 1).

In the crystal structure, the dimers are linked through C—H···O hydrogen bonds (Table 1), forming columns along the a-axis. There are C—H···π interactions (Fig. 2), involving minor disordered C11B atom [C11B···Cg1ⁱⁱⁱ = 3.47 (2), H11C···Cg1ⁱⁱⁱ = 2.82 Å; Cg1 = centroid of the ring C1–C6; symmetry code: (iii) x, 3/2-y, -1/2+z].

Experimental

The title compound was obtained in a template/complexation reaction, which was described earlier (Kwiatkowski et al., 2003). A solution of N-methylethylenediamine (1 mmol) in absolute EtOH (10 ml) was added under stirring to a freshly filtered solution of vanadium(V) oxytriethoxide (1 mmol) in absolute EtOH (50 ml), producing a yellow suspension of the intermediate. Salicylaldehyde (1 mmol) dissolved in absolute EtOH was added to the aforementioned suspension. After refluxing (70 ml) of the resulting mixture for 2 h and its cooling to room temperature, the separated solids were filtered off, washed several times with EtOH, recrystallized from DMSO-EtOH mixture and dried over molecular sieves.