Hexa­aquadodeca-μ2-chlorido-octa­hedro-hexa­niobium diiodide

Schröder, F.; Köckerling, M.

doi:10.1107/S2414314621006969

inorganic compounds

IUCrDATA

ISSN: 2414-3146

Volume 6| Part 7| July 2021| x210696

https://doi.org/10.1107/S2414314621006969

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Hexaaquadodeca-μ₂-chlorido-octahedro-hexaniobium diiodide

Florian Schröder ^a and Martin Köckerling ^a ^*

^aUniversität Rostock, Institut für Chemie, Anorganische Festkörperchemie, Albert-Einstein-Str. 3a, D-18059 Rostock, Germany
^*Correspondence e-mail: Martin.Koeckerling@uni-rostock.de

Edited by M. Bolte, Goethe-Universität Frankfurt, Germany (Received 1 June 2021; accepted 6 July 2021; online 20 July 2021)

The title compound, [Nb₆Cl₁₂(H₂O)₆]I₂, consists of the niobium cluster cation [Nb₆Cl₁₂(H₂O)₆]²⁺ and two non-coordinating, charge-balancing iodide ions. The edges of the Nb₆ octahedron are bridged by chlorido ligands. Each Nb atom is further coordinated by a water ligand. The cluster cation has a charge of +2, which is balanced by that of two iodide anions.

Keywords: crystal structure; cluster; niobium; iodide.

CCDC reference: 2094789

Structure description

Cluster complexes of transition metals have been an interesting research area for many years (Cotton, 1964 ; Simon, 1988 ). Ligand-exchange reactions in solvents have opened up a wide field of new cluster compounds (Lemoine et al., 2019 ), of which so far iodides have been investigated much less than chlorides.

The title compound crystallizes in the trigonal space group P $[\overline{3}]$ 1m. The asymmetric unit consists of an [NbCl₂(H₂O)]_0.5 unit, which is located close to the Wyckoff site 1a with $[\overline{3}]$ m symmetry, and one-sixth of an iodide ion. The Nb₆ unit is a metal atom octahedron with an Nb—Nb bond length of 2.8960 (4) Å. The twelve μ₂ bridging positions of the inner ligand sphere are occupied by chlorido ligands. An average Nb—Cl bonding length of 2.456 Å and an average Nb—Cl—Nb angle of 72.31° are present. The six positions of the outer ligand sphere are occupied by water ligands, reaching Nb—O bond lengths of 2.250 (2) Å. The structure of the cluster cation and the packing are shown in Figs. 1 and 2. The charge of the two iodide anions are counter-balanced by that of the doubly positive charged cluster cation [Nb₆Cl₁₂(H₂O)₆]²⁺. Based on the ion ratio and Nb—Nb bond lengths of comparable structures, 16 cluster-based electrons (CBE) are present. Even though six water molecules are present per formula unit, hydrogen bonding is essentially not present in crystals of the title compound, because the large iodide anions separate the cluster units such that the shortest O⋯O distance is 4.432 (2) Å. The only weak hydrogen-type bonding contact exists between I1 and O1 with an O1—H1A⋯O1 distance of 3.501 (1) Å.

Figure 1
Perspective view of the title compound with atom labelling for the asymmetric unit. Displacement ellipsoids are shown at the 50% probability level.

Figure 2
Packing of the cluster cations and iodide anions in the crystal of the title compound.

Synthesis and crystallization

Starting from the compound [Nb₆Cl₁₂I₂(H₂O)₄]·4H₂O (Schäfer et al., 1972 ; Brnicevic et al., 1981 ), the compound [Nb₆Cl₁₂(H₂O)₆]I₂ can be synthesized in acceptable yields.

Amounts of 100 mg (72.42 µmol) of [Nb₆Cl₁₂I₂(H₂O)₄]·4H₂O and 100 mg (667.16 µmol) of NaI were dissolved in 8 ml (444.07 mmol) of degassed water at room temperature and then filtered. The obtained dark-green solution was evaporated in a crystallizing shell for 4 d. Large black single crystals were obtained in remnants of NaI. After washing several times with acetone, 65.0 mg (48.34 µmol, yield: 65%) of [Nb₆Cl₁₂(H₂O)₆]I₂ were obtained. The cluster compound was further characterized as follows: Elemental analysis: M [H₁₂Cl₁₂I₂O₆Nb₆] = 1344.764: found H = 1.01% (calc. 0.90%); ¹H NMR: (MeCN-d₃ was refluxed for several hours with CaH₂ and finally distilled under Schlenk conditions) (MeCN-d₃, 300 MHz, 300 K, p.p.m.): δ = 2.14 (s, 12H, H₂O); IR (300 K, ATR, cm⁻¹): ν = 406 (s), 600 (s), 692 (s), 1587 (vs), 3140 (s), 3256 (s).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. Two reflections (001 and 010) were omitted from the structure refinement because their intensities were affected by the beam stop.

Table 1
Experimental details

Crystal data
Chemical formula	[Nb₆Cl₁₂(H₂O)₆]I₂
M_r	1344.76
Crystal system, space group	Trigonal, P $[\overline{3}]$ 1m
Temperature (K)	123
a, c (Å)	9.3911 (8), 8.6576 (9)
V (Å³)	661.2 (1)
Z	1
Radiation type	Mo Kα
μ (mm⁻¹)	6.08
Crystal size (mm)	0.20 × 0.20 × 0.16

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2017 )
No. of measured, independent and observed [I > 2σ(I)] reflections	43489, 1059, 1058
R_int	0.031
(sin θ/λ)_max (Å⁻¹)	0.806

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.013, 0.034, 1.38
No. of reflections	1059
No. of parameters	27
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.72, −0.81
Computer programs: APEX3 and SAINT (Bruker, 2017), SHELXS2014 (Sheldrick, 2008 ), SHELXL2014 (Sheldrick, 2015 ), DIAMOND (Brandenburg & Putz, 2019 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 2094789

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314621006969/bt4115sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314621006969/bt4115Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX3 (Bruker, 2017); cell refinement: SAINT (Bruker, 2017); data reduction: SAINT (Bruker, 2017); program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg & Putz, 2019); software used to prepare material for publication: publCIF (Westrip, 2010).

Hexaaquadodeca-µ₂-chlorido-octahedro-hexaniobium diiodide top

Crystal data top

[Nb₆Cl₁₂(H₂O)₆]I₂	D_x = 3.377 Mg m⁻³
M_r = 1344.76	Mo Kα radiation, λ = 0.71073 Å
Trigonal, P31m	Cell parameters from 9268 reflections
a = 9.3911 (8) Å	θ = 2.5–34.9°
c = 8.6576 (9) Å	µ = 6.08 mm⁻¹
V = 661.2 (1) Å³	T = 123 K
Z = 1	Block, black
F(000) = 616	0.20 × 0.20 × 0.16 mm

Data collection top

Bruker APEXII CCD diffractometer	1058 reflections with I > 2σ(I)
Radiation source: microfocus sealed tube	R_int = 0.031
φ and ω scans	θ_max = 35.0°, θ_min = 3.4°
Absorption correction: multi-scan (SADABS, Bruker, 2017)	h = −15→15
	k = −15→15
43489 measured reflections	l = −13→13
1059 independent reflections

Refinement top

Refinement on F²	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F² > 2σ(F²)] = 0.013	H-atom parameters constrained
wR(F²) = 0.034	w = 1/[σ²(F_o²) + (0.005P)² + 1.1433P] where P = (F_o² + 2F_c²)/3
S = 1.38	(Δ/σ)_max < 0.001
1059 reflections	Δρ_max = 0.72 e Å⁻³
27 parameters	Δρ_min = −0.81 e Å⁻³
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0071 (3)

Special details top

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. The H atom was located in a difference maps, but refined using a riding model with O—H = 0.85 Å and with U(H) = 1.5 U_eq(O).

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Nb1	0.0000	0.17816 (2)	0.13652 (2)	0.00709 (5)
Cl1	−0.21059 (3)	0.21059 (3)	0.0000	0.01203 (9)
Cl2	0.21271 (6)	0.21271 (6)	0.32300 (6)	0.01238 (9)
O1	0.0000	0.3770 (2)	0.2816 (2)	0.0167 (3)
H1A	0.0851	0.4473	0.3300	0.025*
I1	0.333333	0.666667	0.5000	0.01368 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Nb1	0.00681 (8)	0.00640 (6)	0.00821 (8)	0.00340 (4)	0.00	−0.00114 (4)
Cl1	0.0111 (1)	0.0111 (1)	0.0173 (2)	0.0082 (2)	−0.0021 (1)	−0.0021 (1)
Cl2	0.0136 (2)	0.0136 (2)	0.0106 (2)	0.0072 (2)	−0.0044 (1)	−0.0044 (1)
O1	0.0135 (7)	0.0154 (5)	0.0205 (7)	0.0067 (3)	0.00	−0.0085 (5)
I1	0.01186 (7)	0.01186 (7)	0.0173 (1)	0.00593 (4)	0.00	0.00

Geometric parameters (Å, º) top

Nb1—O1	2.250 (2)	Nb1—Nb1ⁱ	2.8960 (4)
Nb1—Cl1	2.4502 (4)	Nb1—Nb1ⁱⁱ	2.8980 (4)
Nb1—Cl1ⁱ	2.4502 (4)	Nb1—Nb1^iv	2.8980 (4)
Nb1—Cl2ⁱⁱ	2.4605 (4)	Cl1—Nb1ⁱⁱⁱ	2.4501 (4)
Nb1—Cl2	2.4605 (4)	Cl2—Nb1^iv	2.4605 (4)
Nb1—Nb1ⁱⁱⁱ	2.8960 (4)	O1—H1A	0.8500

O1—Nb1—Cl1	80.29 (4)	Nb1ⁱⁱⁱ—Nb1—Nb1ⁱ	60.04 (1)
O1—Nb1—Cl1ⁱ	80.28 (4)	O1—Nb1—Nb1ⁱⁱ	135.94 (3)
Cl1—Nb1—Cl1ⁱ	88.699 (7)	Cl1—Nb1—Nb1ⁱⁱ	96.180 (6)
O1—Nb1—Cl2ⁱⁱ	82.02 (4)	Cl1ⁱ—Nb1—Nb1ⁱⁱ	143.773 (8)
Cl1—Nb1—Cl2ⁱⁱ	88.26 (1)	Cl2ⁱⁱ—Nb1—Nb1ⁱⁱ	53.922 (8)
Cl1ⁱ—Nb1—Cl2ⁱⁱ	162.30 (1)	Cl2—Nb1—Nb1ⁱⁱ	96.56 (1)
O1—Nb1—Cl2	82.02 (4)	Nb1ⁱⁱⁱ—Nb1—Nb1ⁱⁱ	59.977 (5)
Cl1—Nb1—Cl2	162.30 (1)	Nb1ⁱ—Nb1—Nb1ⁱⁱ	90.0
Cl1ⁱ—Nb1—Cl2	88.26 (1)	O1—Nb1—Nb1^iv	135.94 (3)
Cl2ⁱⁱ—Nb1—Cl2	89.35 (3)	Cl1—Nb1—Nb1^iv	143.773 (8)
O1—Nb1—Nb1ⁱⁱⁱ	134.05 (4)	Cl1ⁱ—Nb1—Nb1^iv	96.180 (6)
Cl1—Nb1—Nb1ⁱⁱⁱ	53.773 (8)	Cl2ⁱⁱ—Nb1—Nb1^iv	96.56 (1)
Cl1ⁱ—Nb1—Nb1ⁱⁱⁱ	96.23 (1)	Cl2—Nb1—Nb1^iv	53.922 (8)
Cl2ⁱⁱ—Nb1—Nb1ⁱⁱⁱ	96.00 (1)	Nb1ⁱⁱⁱ—Nb1—Nb1^iv	90.0
Cl2—Nb1—Nb1ⁱⁱⁱ	143.919 (8)	Nb1ⁱ—Nb1—Nb1^iv	59.977 (5)
O1—Nb1—Nb1ⁱ	134.05 (4)	Nb1ⁱⁱ—Nb1—Nb1^iv	60.0
Cl1—Nb1—Nb1ⁱ	96.23 (1)	Nb1ⁱⁱⁱ—Cl1—Nb1	72.45 (2)
Cl1ⁱ—Nb1—Nb1ⁱ	53.773 (8)	Nb1—Cl2—Nb1^iv	72.16 (2)
Cl2ⁱⁱ—Nb1—Nb1ⁱ	143.919 (8)	Nb1—O1—H1A	122.0
Cl2—Nb1—Nb1ⁱ	96.01 (1)

Symmetry codes: (i) y, −x+y, −z; (ii) −y, x−y, z; (iii) x−y, x, −z; (iv) −x+y, −x, z.

Acknowledgements

We gratefully acknowledge the maintenance of the XRD equipment through Dr Alexander Villinger (University of Rostock).

Funding information

Funding for this research was provided by: Deutsche Forschungsgemeinschaft (grant No. KO1616-8 to MK).

References

Brandenburg, K. & Putz, H. (2019). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Brnicevic, N., Kojic, B. & Plavsic, D. (1981). Z. Anorg. Allg. Chem. 472, 200–204. CAS Google Scholar
Bruker (2017). APEX3, SADABS and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cotton, F. A. (1964). Inorg. Chem. 3, 1217–1220. CrossRef CAS Web of Science Google Scholar
Lemoine, P., Halet, J.-F. & Cordier, S. (2019). In Ligated Transition Metal Clusters in Solid-State Chemistry: The Legacy of Marcel Sergent, edited by J.-F. Halet, pp. 143–190. Berlin, Heidelberg: Springer. Google Scholar
Schäfer, H., Plautz, B. & Plautz, H. (1972). Z. Anorg. Allg. Chem. 392, 10–22. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Simon, A. (1988). Angew. Chem. 100, 163–188. CrossRef CAS Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar