5,6-Dihydro-1,10-phenanthroline-1,10-diium μ-oxido-bis­[penta­fluoridotantalate(V)]

In the title compound, (C₁₂H₁₂N₂)[Ta₂F₁₀O], the doubly protonated 5,6-dihydro-1,10-phenantroline-1,10-diium cation is located on a twofold rotation axis, whereas the isolated [Ta₂OF₁₀]²⁻ dianion has -1 symmetry. In the so far unknown dianion, the symmetry-related Ta^V atoms are octa­hedrally coordinated by five F atoms and a bridging O atom, the latter being located on an inversion centre. The two pyridine rings in the cation make a dihedral angle of 22.8 (4)°. The cations and dianions are arranged in layers parallel to (100) and are connected through N—H⋯F and C—H⋯F hydrogen-bonding inter­actions into a three-dimensional structure.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.010 Å
• R factor = 0.028
• wR factor = 0.072
• Data-to-parameter ratio = 13.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT234_ALERT_4_C Large Hirshfeld Difference N1     --  C4      ..       0.17 Ang.
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         N1
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C1
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Ta1
PLAT342_ALERT_3_C Low Bond Precision on  C-C Bonds ...............     0.0104 Ang
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          1
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          3

Alert level G
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT007_ALERT_5_G Note: Number of Unrefined D-H Atoms ............          1
PLAT083_ALERT_2_G SHELXL Second Parameter in WGHT Unusually Large.      20.56

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   7 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   2 ALERT type 5 Informative message, check

---

S1. Comment

Metal oxyfluorides have received considerable attention in recent years due to their structure-related properties such as ferroelectricity, piezoelectricity and second-order nonlinear optical activity (Hagerman & Poeppelmeier, 1995; Halasyamani & Poeppelmeier, 1998; Welk et al., 2002). In this article, we report on a new oxidofluoridotantalate with composition [C₁₂H₁₂N₂][Ta₂OF₁₀] that was obtained by means of a two-step hydrothermal method.

The title compound (Fig. 1) contains one diprotonated 5,6-dihydro-1,10-phenantroline-1,10-diium cation (symmetry 2) and one [Ta₂OF₁₀]^2- dianion (symmetry 1). In the latter, the Ta^V ion is coordinated by five fluorine atoms and one oxygen atom, forming an octahedral coordination geometry. It is noteworthy that the title compound features the first oxidofluoridotantalate with composition [Ta₂OF₁₀]^2-. The cation is not flat, as can be expected from the 5,6-dihydro bridging sp³ carbon atoms, with a dihedral angle of of 22.8 (4)° between the two pyridine rings. The cations and dianions are arranged in layers parallel to (100) and are connected through N—H···F and C—H···F hydrogen bonding interactions into a three-dimensional structure (Fig. 2).

It should be noted that the hydrothermal conditions make it possible that parts of the fluorine atoms are replaced by OH^- ions. To exclude the presence of the latter, additional characterisation methods were employed (see details in the experimental part). Moreover, IR spectroscopy revealed no inclusion of OH^- in the compound (Fig. 3).

Related literature

For structure–property relations of metal oxyfluorides, see: Hagerman & Poeppelmeier (1995); Halasyamani & Poeppelmeier (1998); Welk et al. (2002).

S2. Experimental

All chemicals were of reagent grade quality obtained from commercial sources and were used without further purification. The title compound was obtained by using a two-step hydrothermal method in a 50 mL Teflon-lined autoclave. Firstly, 0.66 g Ta₂O₅ (1.5 mmol) was dissolved in 1.11 g HF (40_wt%) (7.4 mmol) and heated to 453 K for 4 hours. After it was cooled, the solution was added into 0.90 mL H₃PO₄ (85_wt%), 0.24 g 2,2'-bipyridine (1.5 mmol), 2.0 mL ethylene glycol and 1.0 mL H₂O. Then the mixture was stirred for half an hour, and transferred into a Teflon-lined stainless steel autoclave (50 mL) and treated at 453 K for 7 days. After the mixture was slowly cooled to room temperature, yellow block-like crystals suitable for X-ray structure determination were obtained. It worth noting that the reaction of 2,2'-bipyridine and ethylene glycol produced the 5,6-dihydro-1,10-phenantroline ligand. The chemical composition of the title compound was confirmed by EDS and elemental analysis. The results of EDS indicate the presence of the elements Ta, F, O, C and N. The Ta composition was quantified by ICP-OES: Anal./Calcd (%): Ta: 48.59/48.12. C, H, and N analysis was performed on a PerkinElmer 2400II elemental analyzer. Anal./Calcd (%): C, 19.16; H, 1.61; N,3.72 %. Found: C, 19.63; H, 1.94; N, 3.17 %. IR (KBr, cm^-1) (Fig. 3): 3110, 3057, 2920, 2861, 1621,1584,1494, 1457, 1431, 1367, 1330, 1282, 1234, 1181, 1149, 1033, 869, 784, 715, 593 and 535.

S3. Refinement

The H atoms bonded to C and N were positioned geometrically and refined using a riding model, with C—H = 0.93 Å for H atoms bound to sp² C atoms, and 0.97 Å for H atoms bound to sp³ C atoms, and with N—H = 0.86 Å, and with U_iso(H) = 1.2 (1.5) times U_eq(C), and U_iso(H) = 1.2 times U_eq(N), respectively. The highest and lowest remaining electron density was located 0.84 Å and 0.72 Å from atom Ta1.

Computing details

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. View of the title molecule with displacement ellipsoids drawn at the 30% probability level [symmetry code A: -x+2, y, -z+3/2].
	Fig. 2. Crystal packing viewed along the c axis. Hydrogen bonding interactions are shown as dashed lines.
	Fig. 3. IR spectrum of the title compound.

5,6-Dihydro-1,10-phenanthroline-1,10-diium µ-oxido-bis[pentafluoridotantalate(V)]

Crystal data

(C12H12N2)[Ta2F10O]	F(000) = 1368
Mr = 752.14	Dx = 2.831 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 3156 reflections
a = 13.536 (2) Å	θ = 2.4–28.3°
b = 11.3031 (17) Å	µ = 12.50 mm^−1
c = 11.5316 (17) Å	T = 296 K
β = 90.093 (2)°	Block, yellow
V = 1764.4 (5) Å^3	0.21 × 0.20 × 0.17 mm
Z = 4

Data collection

Bruker APEXII CCD diffractometer	1725 independent reflections
Radiation source: fine-focus sealed tube	1573 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.029
φ and ω scans	θmax = 26.0°, θmin = 2.9°
Absorption correction: multi-scan (SADABS; Bruker, 2008)	h = −13→16
Tmin = 0.179, Tmax = 0.225	k = −13→13
4738 measured reflections	l = −14→12

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.072	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0278P)^2 + 20.5568P] where P = (Fo^2 + 2Fc^2)/3
1725 reflections	(Δ/σ)max < 0.001
124 parameters	Δρmax = 1.96 e Å^−3
0 restraints	Δρmin = −1.14 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.

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

	x	y	z	Uiso*/Ueq
Ta1	0.193168 (19)	0.18732 (2)	0.13666 (2)	0.03630 (12)
C2	0.9169 (6)	0.2166 (8)	0.9660 (7)	0.0499 (19)
H2A	0.9123	0.1448	1.0050	0.060*
C1	0.9649 (4)	0.2220 (5)	0.8646 (5)	0.0210 (10)
C5	0.9738 (5)	0.3254 (5)	0.8051 (5)	0.0332 (13)
N1	0.9318 (6)	0.4270 (7)	0.8502 (7)	0.069 (2)
H1A	0.9361	0.4931	0.8136	0.083*
C4	0.8832 (7)	0.4207 (9)	0.9546 (7)	0.062 (2)
H4A	0.8558	0.4890	0.9858	0.075*
C3	0.8742 (7)	0.3164 (9)	1.0135 (7)	0.060 (2)
H3A	0.8403	0.3127	1.0834	0.072*
F1	0.2944 (5)	0.0732 (6)	0.1479 (5)	0.093 (2)
F2	0.1355 (4)	0.1192 (5)	0.2716 (4)	0.0684 (14)
F3	0.1159 (4)	0.0811 (4)	0.0475 (4)	0.0692 (15)
F4	0.0908 (5)	0.2992 (5)	0.1343 (7)	0.0867 (19)
F5	0.2665 (4)	0.2877 (5)	0.2351 (5)	0.0720 (15)
O1	0.2500	0.2500	0.0000	0.082 (3)
C6	1.0104 (5)	0.1139 (6)	0.8134 (6)	0.0408 (15)
H6A	0.9827	0.0436	0.8490	0.049*
H6B	1.0811	0.1141	0.8270	0.049*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ta1	0.03744 (18)	0.03940 (18)	0.03206 (18)	−0.00695 (11)	0.00427 (11)	−0.00056 (11)
C2	0.047 (4)	0.069 (5)	0.033 (4)	−0.008 (4)	0.001 (3)	0.012 (4)
C1	0.023 (3)	0.023 (2)	0.016 (2)	−0.001 (2)	0.004 (2)	0.002 (2)
C5	0.039 (3)	0.032 (3)	0.028 (3)	0.000 (3)	0.001 (3)	−0.004 (2)
N1	0.087 (5)	0.062 (5)	0.059 (4)	0.015 (4)	0.000 (4)	−0.007 (4)
C4	0.069 (6)	0.076 (6)	0.042 (4)	0.016 (5)	0.015 (4)	−0.022 (4)
C3	0.056 (5)	0.099 (7)	0.025 (4)	0.003 (4)	0.013 (3)	−0.012 (4)
F1	0.094 (4)	0.117 (5)	0.066 (3)	0.058 (4)	−0.006 (3)	−0.024 (3)
F2	0.097 (4)	0.066 (3)	0.042 (3)	−0.019 (3)	0.024 (3)	0.005 (2)
F3	0.095 (4)	0.065 (3)	0.048 (3)	−0.038 (3)	−0.010 (3)	0.002 (2)
F4	0.070 (4)	0.061 (3)	0.128 (6)	0.017 (3)	−0.009 (4)	0.007 (3)
F5	0.071 (3)	0.082 (4)	0.063 (3)	−0.031 (3)	0.001 (3)	−0.023 (3)
O1	0.106 (8)	0.095 (7)	0.045 (5)	−0.054 (6)	0.018 (5)	0.008 (5)
C6	0.043 (4)	0.031 (3)	0.048 (4)	0.002 (3)	0.005 (3)	0.004 (3)

Geometric parameters (Å, º)

Ta1—F4	1.877 (5)	C5—N1	1.384 (9)
Ta1—F5	1.886 (5)	C5—C5^i	1.455 (13)
Ta1—F1	1.886 (5)	N1—C4	1.374 (11)
Ta1—O1	1.8924 (3)	N1—H1A	0.8600
Ta1—F3	1.895 (4)	C4—C3	1.366 (13)
Ta1—F2	1.905 (4)	C4—H4A	0.9300
C2—C1	1.340 (9)	C3—H3A	0.9300
C2—C3	1.381 (12)	O1—Ta1^ii	1.8924 (3)
C2—H2A	0.9300	C6—C6^i	1.488 (14)
C1—C5	1.361 (8)	C6—H6A	0.9700
C1—C6	1.490 (8)	C6—H6B	0.9700
F4—Ta1—F5	89.5 (3)	C5—C1—C6	117.8 (5)
F4—Ta1—F1	176.8 (3)	C1—C5—N1	119.1 (6)
F5—Ta1—F1	89.3 (3)	C1—C5—C5^i	119.0 (4)
F4—Ta1—O1	92.1 (2)	N1—C5—C5^i	122.0 (5)
F5—Ta1—O1	93.55 (17)	C4—N1—C5	118.9 (8)
F1—Ta1—O1	91.0 (2)	C4—N1—H1A	120.5
F4—Ta1—F3	90.7 (3)	C5—N1—H1A	120.5
F5—Ta1—F3	175.8 (2)	C3—C4—N1	121.6 (8)
F1—Ta1—F3	90.2 (3)	C3—C4—H4A	119.2
O1—Ta1—F3	90.60 (15)	N1—C4—H4A	119.2
F4—Ta1—F2	88.9 (3)	C4—C3—C2	118.1 (7)
F5—Ta1—F2	88.1 (2)	C4—C3—H3A	121.0
F1—Ta1—F2	88.1 (3)	C2—C3—H3A	121.0
O1—Ta1—F2	178.07 (15)	Ta1^ii—O1—Ta1	180.00 (2)
F3—Ta1—F2	87.7 (2)	C1—C6—C6^i	108.2 (5)
C1—C2—C3	120.8 (7)	C1—C6—H6A	110.1
C1—C2—H2A	119.6	C6^i—C6—H6A	110.1
C3—C2—H2A	119.6	C1—C6—H6B	110.1
C2—C1—C5	121.5 (6)	C6^i—C6—H6B	110.1
C2—C1—C6	120.7 (6)	H6A—C6—H6B	108.4
C3—C2—C1—C5	0.4 (11)	C5^i—C5—N1—C4	179.8 (8)
C3—C2—C1—C6	−179.6 (7)	C5—N1—C4—C3	−1.0 (13)
C2—C1—C5—N1	−0.4 (10)	N1—C4—C3—C2	1.0 (14)
C6—C1—C5—N1	179.6 (6)	C1—C2—C3—C4	−0.7 (13)
C2—C1—C5—C5^i	−179.6 (8)	C2—C1—C6—C6^i	138.0 (7)
C6—C1—C5—C5^i	0.4 (10)	C5—C1—C6—C6^i	−42.0 (9)
C1—C5—N1—C4	0.7 (11)

Symmetry codes: (i) −x+2, y, −z+3/2; (ii) −x+1/2, −y+1/2, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···F4^iii	0.86	2.45	3.114 (10)	135
C4—H4A···F1^iv	0.93	2.26	3.066 (9)	145
C6—H6A···F3^v	0.97	2.28	3.219 (8)	163
C6—H6B···F5^vi	0.97	2.45	3.268 (9)	142

Symmetry codes: (iii) −x+1, −y+1, −z+1; (iv) x+1/2, y+1/2, z+1; (v) −x+1, −y, −z+1; (vi) −x+3/2, −y+1/2, −z+1.