Bis(ethyl­enedi­ammonium) μ-ethyl­enedi­aminetetra­acetato-1κ³O,N,O′:2κ³O′′,N′,O′′′-bis­[tri­oxidomolybdate(VI)] tetra­hydrate

The title compound is a binuclear complex of molybdenum with a ethyl­enedi­amine­tretra­acetate ligand bridging two MoO₃ units.

Abstract

The title compound, (C₂H₁₀N₂)₂[(C₁₀H₁₂N₂O₈)(MoO₃)₂]·4H₂O, which crystallizes in the monoclinic C2/c space group, was obtained by mixing molybdenum oxide, ethyl­enedi­amine and ethyl­enedi­amine­tetra­acetic acid (H₄edta) in a 2:4:1 ratio. The complex anion contains two MoO₃ units bridged by an edta⁴⁻ anion. The midpoint of the central C—C bond of the edta⁴⁻ anion is located on a crystallographic inversion centre. The independent Mo atom is tridentately coordin­ated by a nitro­gen atom and two carboxyl­ate groups of the edta⁴⁻ ligand, together with the three oxo ligands, producing a distorted octa­hedral coordination environment. In the three-dimensional supra­molecular crystal structure, the dinuclear anions, the organo­ammonium counter-ions and the solvent water mol­ecules are linked by N—H⋯O_w, N—H⋯O_edta and O—H⋯O hydrogen bonds.

Structure description

The advancement of materials science has meant that many well-established materials, such as metals, ceramics or plastics, cannot meet the demand for new applications (photovoltaic cells, field-effect transistors, etc.). This desire to design new functional materials demands enormous research effort. In order to overcome this challenge, scientists quickly understood that mixtures of materials could have properties superior to those of their pure counterparts, and thus meet this demand. Hybrid framework materials research is one of the fastest growing research fields.

Their unique hybrid nature enables the combination of properties from both inorganic and organic materials (Cheetham & Rao, 2007 ▸). As organic ligands, polycarboxyl­ates are multidentate chelating agents, widespread in nature and industry, due to their ability to coordinate to various transition metals in different ratios. In this field, the study of molybdenum polycarboxyl­ate complexes has led to thorough investigation over the past three decades. Some well-characterized mono-, bi- and polynuclear molybdenum and tungsten complexes have been reported, for example [(H₂TEMED)Mo₂O₆(H₂edta)]·H₂O (TMED = tetra­methyl­ethylenedi­amine; Kumar et al., 2012 ▸), Mo₂(O₂CCH₂OH)₄, M₂[MoO₃(C₂O₄)] (M = Na, K, Rb, Cs) and Na₂[MO₂(C₆H₆O₇)₂]·3H₂O (M = Mo, W; Cotton et al., 2002 ▸; Cindrić et al., 2000 ▸; Zhou et al., 1999 ▸), Na₂K₂[Mo₂O₆(edta)]·10H₂O and Na₄[W₂O₆(edta)]·8H₂O (Lin et al., 2006 ▸). In our study, the reaction of H₄edta (ethyl­enedi­amine­tetra­acetic acid) with molybdenum oxide has been investigated, and a new binuclear 2:1 Mo–edta complex, (C₂H₁₀N₂)₂[(C₁₀H₁₂N₂O₈)(MoO₃)₂]·4H₂O, including edta⁴⁻ as ligand has been isolated and structurally characterized.

The single-crystal structure shows that the 2:1 Mo–edta complex anion of the title compound is discrete (Fig. 1 ▸). All of the carb­oxy­lic groups of H₄edta are deprotonated, coordin­ating the molybdenum oxide groups by nitro­gen and two oxygen atoms. The edta⁴⁻ ligand itself is a bridge between the two MoO₃ units, and the midpoint of the central C—C bond is situated on an inversion centre. In the 2:1 Mo–edta complex, the edta⁴⁻ ligand thus chelates a pair of Mo^VI centres, in a tridentate fashion, giving a trans configuration to the complex. Each Mo^VI ion is chelated by the edta⁴⁻ ligand, simultaneously forming two glycinato rings occupying contiguous vertices that define one face of the coordination polyhedron. The other three vertices of the opposite face are occupied by three terminal oxo atoms of the MoO₃ unit, completing the octa­hedral geometry. In the complex, the Mo—O bond lengths are in the range 1.7195 (16) to 1.7686 (15) Å for Mo=O_t groups (O_t are terminal oxygen atoms: O5, O6 and O7). The resulting bond angles O_t—Mo—O_t are 107.27 (7), 103.83 (7) and 106.75 (7)°, considerably larger than the expected value of 90° for a regular octa­hedron, confirming the distortion from octa­hedral geometry.

Figure 1.

Mol­ecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. Unlabelled atoms are generated by inversion symmetry.

The crystal packing can be rationalized in terms of non-bonding inter­actions between the three tectons: the Mo–edta complex anion, two (C₂H₁₀N₂)⁺ cations and four lattice water mol­ecules. These units are linked through hydrogen bonds of the type N—H⋯O_water, N—H⋯O_edta and O—H⋯O (Table 1 ▸). This inter­connection leads to the supra­molecular structure, as shown in Fig. 2 ▸.

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2C⋯O1i	0.91	1.93	2.795 (2)	159
N2—H2D⋯O10	0.91	2.00	2.715 (4)	134
N2—H2D⋯O7ii	0.91	2.21	2.786 (2)	121
N2—H2E⋯O6iii	0.91	1.84	2.748 (2)	172
N3—H3C⋯O9i	0.91	1.88	2.785 (3)	170
N3—H3D⋯O1iv	0.91	1.98	2.838 (2)	156
N3—H3E⋯O5v	0.91	1.84	2.753 (2)	177
O1—H1A⋯O5vi	0.87	1.83	2.694 (2)	173
O1—H1B⋯O2	0.87	1.83	2.694 (2)	173
O10—H10A⋯O8	0.87	1.86	2.692 (4)	160
O10—H10B⋯O8i	0.87	2.13	2.978 (4)	166

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .

Figure 2.

Supra­molecular arrangement of the title compound with hydrogen bonds shown as dotted lines.

Synthesis and crystallization

Solid molybdenum oxide (4 mmol) and ethyl­enedi­amine (4 mmol) were mixed in 30 ml of distilled water. To this mixture were slowly added 2 mmol of ethyl­enediammine­tetra­acetic acid (H₄edta) under vigorous stirring. The solution was then stirred for 2 h at room temperature. The colourless solution thus obtained was left at room temperature for slow evaporation of water. After a few days, colourless crystals (yield 13.6% based on Mo) were obtained.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸.

Table 2. Experimental details.

Crystal data
Chemical formula	(C2H10N2)2[(C10H12N2O8)(MoO3)2]·4H2O
M r	772.40
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	150
a, b, c (Å)	22.5897 (14), 7.5100 (4), 16.3743 (10)
β (°)	94.716 (2)
V (Å3)	2768.5 (3)
Z	4
Radiation type	Mo Kα
μ (mm−1)	1.00
Crystal size (mm)	0.17 × 0.17 × 0.13
Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 ▸)
Tmin, Tmax	0.691, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	24031, 3192, 2946
R int	0.032
(sin θ/λ)max (Å−1)	0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S	0.022, 0.060, 1.06
No. of reflections	3192
No. of parameters	189
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å−3)	0.67, −1.06

Computer programs: APEX2 and SAINT (Bruker, 2016 ▸), SHELXT2018/2 (Sheldrick, 2015a ▸), SHELXL2018/32 (Sheldrick, 2015b ▸), Mercury (Macrae et al., 2020 ▸) and publCIF (Westrip, 2010 ▸).

Supplementary Material

CCDC reference: 2368916

Additional supporting information: crystallographic information; 3D view; checkCIF report

full crystallographic data

Bis(ethylenediammonium) µ-ethylenediaminetetraacetato-1κ³O,N,O':2κ³O'',N',O'''-bis[trioxidomolybdate(VI)] tetrahydrate . Crystal data

(C2H10N2)2[Mo2(C10H12N2O8)O6]·4H2O	F(000) = 1576
Mr = 772.40	Dx = 1.853 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 22.5897 (14) Å	Cell parameters from 9873 reflections
b = 7.5100 (4) Å	θ = 2.9–27.5°
c = 16.3743 (10) Å	µ = 1.00 mm−1
β = 94.716 (2)°	T = 150 K
V = 2768.5 (3) Å3	Block, colourless
Z = 4	0.17 × 0.17 × 0.13 mm

Bis(ethylenediammonium) µ-ethylenediaminetetraacetato-1κ³O,N,O':2κ³O'',N',O'''-bis[trioxidomolybdate(VI)] tetrahydrate . Data collection

Bruker APEXII CCD diffractometer	2946 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.032
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	θmax = 27.5°, θmin = 1.8°
Tmin = 0.691, Tmax = 0.746	h = −29→29
24031 measured reflections	k = −9→9
3192 independent reflections	l = −20→21

Bis(ethylenediammonium) µ-ethylenediaminetetraacetato-1κ³O,N,O':2κ³O'',N',O'''-bis[trioxidomolybdate(VI)] tetrahydrate . Refinement

Refinement on F2	Primary atom site location: dual
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.022	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.060	H-atom parameters constrained
S = 1.06	w = 1/[σ2(Fo2) + (0.0247P)2 + 9.3382P] where P = (Fo2 + 2Fc2)/3
3192 reflections	(Δ/σ)max = 0.001
189 parameters	Δρmax = 0.67 e Å−3
0 restraints	Δρmin = −1.06 e Å−3

Bis(ethylenediammonium) µ-ethylenediaminetetraacetato-1κ³O,N,O':2κ³O'',N',O'''-bis[trioxidomolybdate(VI)] tetrahydrate . Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Mo1	0.34131 (2)	0.30046 (2)	0.43898 (2)	0.01140 (6)
O2	0.38304 (7)	0.07064 (19)	0.38526 (10)	0.0184 (3)
O3	0.34930 (6)	0.3750 (2)	0.31149 (9)	0.0153 (3)
O5	0.32695 (7)	0.5278 (2)	0.45742 (9)	0.0167 (3)
O6	0.27328 (7)	0.1984 (2)	0.41260 (10)	0.0192 (3)
O7	0.36649 (7)	0.2195 (2)	0.53376 (10)	0.0199 (3)
O8	0.46292 (8)	−0.0988 (2)	0.38094 (12)	0.0305 (4)
O9	0.40393 (8)	0.4592 (3)	0.21238 (10)	0.0313 (4)
N1	0.44444 (7)	0.3699 (2)	0.42662 (10)	0.0110 (3)
N2	0.68095 (9)	−0.1480 (2)	0.31790 (11)	0.0180 (4)
H2C	0.682765	−0.194661	0.266874	0.022*
H2D	0.644495	−0.169814	0.335592	0.022*
H2E	0.709362	−0.199255	0.352923	0.022*
N3	0.68986 (8)	0.3285 (2)	0.39152 (11)	0.0166 (4)
H3C	0.662370	0.374203	0.353458	0.020*
H3D	0.726961	0.352136	0.376498	0.020*
H3E	0.685339	0.379149	0.441115	0.020*
C1	0.43883 (10)	0.0440 (3)	0.39471 (13)	0.0165 (4)
C2	0.46667 (9)	0.4795 (3)	0.49874 (12)	0.0136 (4)
H2A	0.458550	0.415662	0.549512	0.016*
H2B	0.444417	0.593202	0.497625	0.016*
C3	0.44903 (9)	0.4682 (3)	0.34868 (12)	0.0158 (4)
H3A	0.486764	0.435686	0.325738	0.019*
H3B	0.450105	0.597629	0.360192	0.019*
C4	0.68156 (10)	0.1326 (3)	0.39721 (13)	0.0181 (4)
H4A	0.640934	0.106237	0.412324	0.022*
H4B	0.710243	0.083077	0.440266	0.022*
C5	0.39759 (10)	0.4287 (3)	0.28535 (13)	0.0159 (4)
C6	0.47677 (9)	0.1985 (3)	0.42775 (15)	0.0184 (4)
H6A	0.492092	0.171560	0.484797	0.022*
H6B	0.511335	0.210675	0.394705	0.022*
C7	0.69112 (12)	0.0470 (3)	0.31517 (13)	0.0225 (5)
H7A	0.663501	0.100557	0.271922	0.027*
H7B	0.732207	0.070407	0.301180	0.027*
O1	0.30869 (7)	−0.2039 (2)	0.34909 (9)	0.0180 (3)
H1A	0.317459	−0.290614	0.383210	0.027*
H1B	0.333866	−0.120160	0.364109	0.027*
O10	0.56206 (14)	−0.0882 (7)	0.30040 (19)	0.1003 (14)
H10A	0.533675	−0.115649	0.330976	0.151*
H10B	0.549760	−0.103261	0.249098	0.151*

Bis(ethylenediammonium) µ-ethylenediaminetetraacetato-1κ³O,N,O':2κ³O'',N',O'''-bis[trioxidomolybdate(VI)] tetrahydrate . Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Mo1	0.01159 (9)	0.01140 (9)	0.01128 (9)	−0.00124 (6)	0.00129 (6)	−0.00028 (6)
O2	0.0146 (7)	0.0131 (7)	0.0272 (8)	−0.0018 (6)	−0.0006 (6)	−0.0051 (6)
O3	0.0139 (7)	0.0207 (7)	0.0113 (7)	−0.0022 (6)	−0.0005 (5)	0.0000 (6)
O5	0.0197 (8)	0.0149 (7)	0.0157 (7)	0.0013 (6)	0.0031 (6)	−0.0022 (6)
O6	0.0142 (7)	0.0206 (8)	0.0229 (8)	−0.0029 (6)	0.0024 (6)	−0.0023 (6)
O7	0.0201 (8)	0.0226 (8)	0.0172 (7)	−0.0033 (6)	0.0021 (6)	0.0059 (6)
O8	0.0238 (9)	0.0153 (8)	0.0507 (12)	0.0053 (7)	−0.0067 (8)	−0.0107 (8)
O9	0.0263 (9)	0.0548 (12)	0.0123 (7)	−0.0165 (8)	−0.0016 (7)	0.0047 (8)
N1	0.0129 (8)	0.0100 (7)	0.0097 (7)	−0.0009 (6)	−0.0016 (6)	−0.0013 (6)
N2	0.0225 (9)	0.0163 (9)	0.0152 (8)	0.0008 (7)	0.0019 (7)	0.0001 (7)
N3	0.0183 (9)	0.0176 (9)	0.0137 (8)	0.0017 (7)	−0.0007 (7)	−0.0025 (7)
C1	0.0174 (10)	0.0132 (9)	0.0185 (10)	0.0003 (8)	−0.0018 (8)	−0.0013 (8)
C2	0.0133 (10)	0.0156 (9)	0.0115 (9)	−0.0025 (7)	−0.0017 (7)	−0.0027 (7)
C3	0.0150 (10)	0.0198 (10)	0.0125 (9)	−0.0062 (8)	0.0001 (7)	0.0020 (8)
C4	0.0234 (11)	0.0170 (10)	0.0138 (9)	0.0003 (8)	0.0019 (8)	−0.0002 (8)
C5	0.0190 (10)	0.0160 (10)	0.0125 (9)	−0.0031 (8)	−0.0002 (8)	0.0000 (8)
C6	0.0130 (10)	0.0141 (10)	0.0273 (11)	0.0015 (8)	−0.0038 (8)	−0.0038 (8)
C7	0.0376 (13)	0.0159 (10)	0.0138 (10)	−0.0012 (9)	0.0013 (9)	−0.0001 (8)
O1	0.0207 (8)	0.0152 (7)	0.0175 (7)	−0.0052 (6)	−0.0025 (6)	0.0023 (6)
O10	0.0533 (18)	0.200 (4)	0.0469 (16)	0.015 (2)	0.0000 (14)	0.007 (2)

Bis(ethylenediammonium) µ-ethylenediaminetetraacetato-1κ³O,N,O':2κ³O'',N',O'''-bis[trioxidomolybdate(VI)] tetrahydrate . Geometric parameters (Å, º)

Mo1—O2	2.1858 (15)	N3—C4	1.487 (3)
Mo1—O3	2.1831 (14)	C1—C6	1.516 (3)
Mo1—O5	1.7686 (15)	C2—C2i	1.534 (4)
Mo1—O6	1.7397 (15)	C2—H2A	0.9900
Mo1—O7	1.7195 (16)	C2—H2B	0.9900
Mo1—N1	2.4121 (17)	C3—H3A	0.9900
O2—C1	1.273 (3)	C3—H3B	0.9900
O3—C5	1.270 (3)	C3—C5	1.521 (3)
O8—C1	1.232 (3)	C4—H4A	0.9900
O9—C5	1.236 (3)	C4—H4B	0.9900
N1—C2	1.492 (2)	C4—C7	1.521 (3)
N1—C3	1.485 (3)	C6—H6A	0.9900
N1—C6	1.479 (3)	C6—H6B	0.9900
N2—H2C	0.9100	C7—H7A	0.9900
N2—H2D	0.9100	C7—H7B	0.9900
N2—H2E	0.9100	O1—H1A	0.8703
N2—C7	1.484 (3)	O1—H1B	0.8697
N3—H3C	0.9100	O10—H10A	0.8701
N3—H3D	0.9100	O10—H10B	0.8702
N3—H3E	0.9100
O2—Mo1—N1	71.68 (6)	O8—C1—C6	119.11 (19)
O3—Mo1—O2	75.25 (6)	N1—C2—C2i	113.4 (2)
O3—Mo1—N1	73.02 (5)	N1—C2—H2A	108.9
O5—Mo1—O2	157.26 (6)	N1—C2—H2B	108.9
O5—Mo1—O3	86.93 (6)	C2i—C2—H2A	108.9
O5—Mo1—N1	89.85 (6)	C2i—C2—H2B	108.9
O6—Mo1—O2	87.34 (6)	H2A—C2—H2B	107.7
O6—Mo1—O3	90.94 (7)	N1—C3—H3A	109.1
O6—Mo1—O5	107.27 (7)	N1—C3—H3B	109.1
O6—Mo1—N1	156.07 (6)	N1—C3—C5	112.68 (16)
O7—Mo1—O2	87.85 (7)	H3A—C3—H3B	107.8
O7—Mo1—O3	155.03 (7)	C5—C3—H3A	109.1
O7—Mo1—O5	103.83 (7)	C5—C3—H3B	109.1
O7—Mo1—O6	106.75 (7)	N3—C4—H4A	109.8
O7—Mo1—N1	84.38 (7)	N3—C4—H4B	109.8
C1—O2—Mo1	122.03 (13)	N3—C4—C7	109.60 (17)
C5—O3—Mo1	123.00 (13)	H4A—C4—H4B	108.2
C2—N1—Mo1	108.51 (11)	C7—C4—H4A	109.8
C3—N1—Mo1	108.40 (12)	C7—C4—H4B	109.8
C3—N1—C2	111.30 (15)	O3—C5—C3	117.47 (18)
C6—N1—Mo1	106.85 (12)	O9—C5—O3	123.7 (2)
C6—N1—C2	109.66 (16)	O9—C5—C3	118.68 (19)
C6—N1—C3	111.95 (16)	N1—C6—C1	113.43 (17)
H2C—N2—H2D	109.5	N1—C6—H6A	108.9
H2C—N2—H2E	109.5	N1—C6—H6B	108.9
H2D—N2—H2E	109.5	C1—C6—H6A	108.9
C7—N2—H2C	109.5	C1—C6—H6B	108.9
C7—N2—H2D	109.5	H6A—C6—H6B	107.7
C7—N2—H2E	109.5	N2—C7—C4	110.94 (18)
H3C—N3—H3D	109.5	N2—C7—H7A	109.5
H3C—N3—H3E	109.5	N2—C7—H7B	109.5
H3D—N3—H3E	109.5	C4—C7—H7A	109.5
C4—N3—H3C	109.5	C4—C7—H7B	109.5
C4—N3—H3D	109.5	H7A—C7—H7B	108.0
C4—N3—H3E	109.5	H1A—O1—H1B	104.5
O2—C1—C6	116.65 (18)	H10A—O10—H10B	109.4
O8—C1—O2	124.2 (2)
Mo1—O2—C1—O8	164.21 (18)	N1—C3—C5—O3	24.0 (3)
Mo1—O2—C1—C6	−13.7 (3)	N1—C3—C5—O9	−159.7 (2)
Mo1—O3—C5—O9	174.61 (18)	N3—C4—C7—N2	−177.90 (18)
Mo1—O3—C5—C3	−9.3 (3)	C2—N1—C3—C5	−143.96 (17)
Mo1—N1—C2—C2i	175.59 (18)	C2—N1—C6—C1	145.79 (18)
Mo1—N1—C3—C5	−24.7 (2)	C3—N1—C2—C2i	−65.2 (3)
Mo1—N1—C6—C1	28.4 (2)	C3—N1—C6—C1	−90.2 (2)
O2—C1—C6—N1	−13.0 (3)	C6—N1—C2—C2i	59.2 (3)
O8—C1—C6—N1	169.0 (2)	C6—N1—C3—C5	92.9 (2)

Symmetry code: (i) −x+1, −y+1, −z+1.

Bis(ethylenediammonium) µ-ethylenediaminetetraacetato-1κ³O,N,O':2κ³O'',N',O'''-bis[trioxidomolybdate(VI)] tetrahydrate . Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2C···O1ii	0.91	1.93	2.795 (2)	159
N2—H2D···O10	0.91	2.00	2.715 (4)	134
N2—H2D···O7iii	0.91	2.21	2.786 (2)	121
N2—H2E···O6iv	0.91	1.84	2.748 (2)	172
N3—H3C···O9ii	0.91	1.88	2.785 (3)	170
N3—H3D···O1v	0.91	1.98	2.838 (2)	156
N3—H3E···O5i	0.91	1.84	2.753 (2)	177
O1—H1A···O5vi	0.87	1.83	2.694 (2)	173
O1—H1B···O2	0.87	1.83	2.694 (2)	173
O10—H10A···O8	0.87	1.86	2.692 (4)	160
O10—H10B···O8ii	0.87	2.13	2.978 (4)	166

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