Tetrafluorodipyridinegermanium, [GeF₄(C₅H₅N)₂]

The molecular title compound was solvothermally synthesized at 373 K and crystallized in the triclinic system, with space group P. The Ge(IV) atom lies on an inversion center and is coordinated by four fluoride anions and two pyridine mol­ecules. Owing to the non-bridging nature of the fluoride anions, this material forms a molecular solid with close packing.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.039
• wR factor = 0.052
• Data-to-parameter ratio = 12.4

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level C:



GOODF_01  Alert C The least squares goodness of fit parameter lies
          outside the range 0.80 <> 2.00
          Goodness of fit given =      0.769

PLAT_710  Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle #      5
                   N1  -GE1 -N1  -C1    -80.00100.00   2.666   1.555   1.555   1.555

PLAT_710  Alert C Delete 1-2-3 or 2-3-4 (CIF) Linear Torsion Angle #     10
                   N1  -GE1 -N1  -C5     99.00100.00   2.666   1.555   1.555   1.555


 0 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 3 Alert Level C = Please check

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S1. Comment

Our research is currently focused on the sovolthermal synthesis of new layered and open-framework materials based on lower group 14 elements. We have used both cationic and anionic structure-directing agents, for the formation of anionic and cationic germanium-, tin- (Salami et al., 2001a,b, 2002; Lansky et al., 2001) and lead-based compounds (Tran et al., 2002). Our interest in these materials stems from their potential to yield chemically and thermally stable microporous zeotype materials, with advantageous materials properties, such as ion-exchange, separations and catalysis. We have successfully synthesized a series of new materials. We are also interested in these materials for their possible semiconducting properties, as well as for low-dimensional solid-state precursors to extended frameworks.

Recently, we used a predominantly non-aqueous environment, where the only source of water was present in the hexafluorophosphoric acid reagent (HF₆P 60 wt% solution in water), which was added to a pyridine solvent. Hexafluorophosphoric acid was selected as a potential anionic structure directing agent. Instead, it acted as source of fluoride. Pyridine and fluoride combined with germanium to form BING-10, an octahedral complex (Fig. 1). The key feature of BING-10 is the non-bridging terminal fluorides, which results in the formation of a neutral molecular solid (Fig. 2). In the case of lead as the building block, the fluorides bridge the metal centres, to give rise to an extended layered material (BING-5; Tran et al., 2002).

BING-10 was obtained as isolated octahedral units that form a neutral molecular solid. Note that pyridine solvent molecules ended up as a monodentate ligand. There is only one crystallographically unique germanium centre, which is bonded to four fluorides and the N atoms of two pyridine molecules. The Ge—F distances are 1.768 (2) and 1.770 (2) Å, while the Ge—N distance is 2.014 (3) Å. All trans ligands define a 180° bond angle, since the molecule resides on the inversion centre. The cis-F—Ge—F bond angles are 89.96 (9) and 90.04 (9)°, while those of F—Ge—N vary from 89.82 (10) to 90.18 (10)°.

We are working further towards obtaining cationic and anionic germanates, especially new layered or open-framework materials. It would appear that a significant concentration of fluoride source in our systems is not suitable for the formation of an extended germanium oxide material. We are currently studying other combinations of germanium sources, solvents and structure directing agents, to isolate inorganic materials with semiconducting or anion-exchange capabilities.

S2. Experimental

The reaction mixture consisted of pyridine, germanium tetraethoxide and HF₆P in a molar ratio of 16:1:1. Sovolthermal synthesis was conducted in a 23 ml capacity Teflon-lined Parr autoclave at 373 K for 6 d. The BING-10 crystals were colourless needles, and one was manually selected for single-crystal X-ray diffraction analysis. The yield was ca 65.7%.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS90 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and ATOMS (Dowty,1999); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. View of the molecules of BING-10, shown with ellipsoids at the 50% probability level.
	Fig. 2. The crystallographic a projection of BING-10, highlighting the germanium tetrafluoride dipyridine complex (colour scheme: Ge blue, F red, N green, C dark grey and H light grey).

(I)

Crystal data

[GeF4(C5H5N)2]	Z = 1
Mr = 306.79	F(000) = 152
Triclinic, P1	Dx = 1.865 Mg m^−3
a = 6.4729 (13) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.0928 (14) Å	Cell parameters from 758 reflections
c = 7.2643 (14) Å	θ = 6.4–43.7°
α = 115.138 (4)°	µ = 2.84 mm^−1
β = 94.921 (4)°	T = 298 K
γ = 109.954 (4)°	Needle, colorless
V = 273.16 (9) Å^3	0.17 × 0.05 × 0.04 mm

Data collection

Bruker SmartApex CCD area-detector diffractometer	1007 independent reflections
Radiation source: fine-focus sealed tube	778 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.058
ω scans	θmax = 25.4°, θmin = 3.2°
Absorption correction: multi-scan (XPREP; Sheldrick, 1997)	h = −7→7
Tmin = 0.827, Tmax = 0.893	k = −8→8
2925 measured reflections	l = −8→8

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)] = 0.039	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.052	H-atom parameters constrained
S = 0.77	w = 1/[σ^2(Fo^2) + (0.007P)^2] where P = (Fo^2 + 2Fc^2)/3
1007 reflections	(Δ/σ)max < 0.001
81 parameters	Δρmax = 0.41 e Å^−3
0 restraints	Δρmin = −0.38 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.

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

	x	y	z	Uiso*/Ueq
Ge1	0.5000	0.5000	0.5000	0.0361 (2)
F1	0.3876 (3)	0.6030 (3)	0.3512 (3)	0.0521 (6)
F2	0.3697 (3)	0.6146 (3)	0.6981 (3)	0.0507 (6)
N1	0.2178 (5)	0.2019 (4)	0.3534 (4)	0.0360 (8)
C1	0.0135 (5)	0.1950 (4)	0.2899 (4)	0.0411 (10)
H1	0.0023	0.3306	0.3150	0.058 (12)*
C5	0.2334 (5)	0.0057 (4)	0.3173 (4)	0.0450 (10)
H5	0.3746	0.0086	0.3598	0.044 (10)*
C2	−0.1812 (7)	−0.0091 (6)	0.1879 (6)	0.0487 (11)
H2	−0.3213	−0.0109	0.1436	0.040 (11)*
C4	0.0430 (7)	−0.2008 (6)	0.2186 (6)	0.0488 (11)
H4	0.0566	−0.3345	0.1968	0.069 (13)*
C3	−0.1649 (7)	−0.2090 (7)	0.1528 (6)	0.0526 (11)
H3	−0.2938	−0.3478	0.0852	0.057 (12)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ge1	0.0308 (4)	0.0350 (3)	0.0416 (4)	0.0131 (3)	0.0050 (3)	0.0193 (3)
F1	0.0456 (14)	0.0450 (13)	0.0606 (15)	0.0128 (11)	−0.0061 (12)	0.0298 (12)
F2	0.0449 (14)	0.0438 (12)	0.0537 (15)	0.0189 (11)	0.0205 (13)	0.0140 (11)
N1	0.0298 (19)	0.0360 (18)	0.040 (2)	0.0125 (15)	0.0049 (16)	0.0189 (16)
C1	0.042 (3)	0.043 (2)	0.041 (3)	0.021 (2)	0.011 (2)	0.020 (2)
C5	0.045 (3)	0.043 (2)	0.050 (3)	0.022 (2)	0.006 (2)	0.024 (2)
C2	0.030 (3)	0.060 (3)	0.047 (3)	0.014 (2)	0.006 (2)	0.024 (2)
C4	0.056 (3)	0.033 (2)	0.045 (3)	0.012 (2)	0.003 (2)	0.017 (2)
C3	0.047 (3)	0.042 (3)	0.049 (3)	0.004 (2)	0.006 (2)	0.018 (2)

Geometric parameters (Å, º)

Ge1—F2	1.7678 (19)	C1—H1	0.9300
Ge1—F2^i	1.7678 (19)	C5—C4	1.379 (4)
Ge1—F1^i	1.7696 (18)	C5—H5	0.9300
Ge1—F1	1.7696 (18)	C2—C3	1.373 (5)
Ge1—N1^i	2.014 (3)	C2—H2	0.9300
Ge1—N1	2.014 (3)	C4—C3	1.362 (5)
N1—C1	1.340 (3)	C4—H4	0.9300
N1—C5	1.344 (3)	C3—H3	0.9300
C1—C2	1.384 (4)
F2—Ge1—F2^i	180.00 (11)	C5—N1—Ge1	119.83 (19)
F2—Ge1—F1^i	90.04 (9)	N1—C1—C2	121.6 (3)
F2^i—Ge1—F1^i	89.96 (9)	N1—C1—H1	119.2
F2—Ge1—F1	89.96 (9)	C2—C1—H1	119.2
F2^i—Ge1—F1	90.04 (9)	N1—C5—C4	121.2 (3)
F1^i—Ge1—F1	180.0	N1—C5—H5	119.7
F2—Ge1—N1^i	89.94 (10)	C4—C5—H5	119.2
F2^i—Ge1—N1^i	90.06 (10)	C3—C2—C1	119.2 (4)
F1^i—Ge1—N1^i	90.18 (10)	C3—C2—H2	120.4
F1—Ge1—N1^i	89.82 (10)	C1—C2—H2	120.4
F2—Ge1—N1	90.06 (10)	C3—C4—C5	120.1 (4)
F2^i—Ge1—N1	89.94 (10)	C3—C4—H4	120.0
F1^i—Ge1—N1	89.82 (10)	C5—C4—H4	120.0
F1—Ge1—N1	90.18 (10)	C4—C3—C2	119.0 (4)
N1^i—Ge1—N1	180.0	C4—C3—H3	120.5
C1—N1—C5	119.0 (3)	C2—C3—H3	120.5
C1—N1—Ge1	121.14 (18)
F2—Ge1—N1—C1	57.7 (2)	N1^i—Ge1—N1—C5	99 (100)
F2^i—Ge1—N1—C1	−122.3 (2)	C5—N1—C1—C2	−0.1 (5)
F1^i—Ge1—N1—C1	147.7 (2)	Ge1—N1—C1—C2	179.6 (2)
F1—Ge1—N1—C1	−32.3 (2)	C1—N1—C5—C4	−0.7 (5)
N1^i—Ge1—N1—C1	−80 (100)	Ge1—N1—C5—C4	179.6 (2)
F2—Ge1—N1—C5	−122.6 (2)	N1—C1—C2—C3	0.7 (5)
F2^i—Ge1—N1—C5	57.4 (2)	N1—C5—C4—C3	1.0 (5)
F1^i—Ge1—N1—C5	−32.6 (2)	C5—C4—C3—C2	−0.5 (6)
F1—Ge1—N1—C5	147.4 (2)	C1—C2—C3—C4	−0.4 (6)

Symmetry code: (i) −x+1, −y+1, −z+1.