The monoclinic polymorph of rac-5,7,7,12,12,14-hexa­methyl-1,4,8,11-tetraazonia­cyclo­tetra­decane bis­(hexa­fluoro­germanate) tetrahydrate

X-ray data were obtained for the monoclinic polymorph of rac-5,7,7,12,12,14-hexa­methyl-1,4,8,11-tetraazonia­cyclo­tetra­decane bis­(hexa­fluoro­germanate) tetrahydrate, (C₁₆H₄₀N₄)[GeF₆]₂·4H₂O. The tetra­aza-macrocyclic cations lie across inversion centers in space group P2₁/c. Water mol­ecules and [GeF₆]^2- anions form zigzag chains, which alternate in a three-dimensional network with the macrocyclic cations. The structure is sustained by multiple hydrogen bonds.

S1. Comment

The ability of crown ethers to stabilize in the form of the proper host–guest complexes of normally unstable or volatile species is well known (Bott et al., 1991; Chuit et al., 1993; Feinberg et al., 1993). Previously, we have shown that crown ethers (18-crown-6, isomers of dicyclohexyl-18-crown-6, mono- and diaza-18-crown-6, and diaza-15-crown-5) provide the opportunity to hold the harmful gaseous (SiF₄; Simonov et al., 1994), intermediate [(SiF₅·H₂O)⁻, SiF₅⁻; Simonov et al., 1996; Gelmboldt et al., 1999] or low-melting substances (BF₃·H₂O; Fonar' et al., 1997) in the form of hydrogen-bonded molecular or ionic complexes. The Ge-containing species GeF₄·2H₂O and (GeF₅·H₂O)⁻, which are similar to these Si-containing complexes, were obtained from the interaction of GeO₂—HF solution with 18-crown-6 and diaza-18-crown-6 (Gelmboldt et al., 1996). The general tendency is that partial replacement? of O atoms by N atoms in the macrocyclic ring or the application of azamacrocycles (Simonov et al., 1998a; Simonov et al., 1998b; Fonari et al., 1998; Fonar' et al., 1999) provokes the extraction of charged species, viz. (SiF₅·H₂O)⁻, SiF₆²⁻, (GeF₅·H₂O)⁻, and GeF₆²⁻ from aqueous solutions of fluorosilicic acid, H₂SiF₆, or its germanium analogue, H₂GeF₆.

We recently reported the single-crystal X-ray structure determination of triclinic rac-5,7,7,12,12,14-hexamethyl-1,4,8,11-tetraazoniacyclotetradecane bis(hexafluorogermanate) tetrahydrate, space group P −1, (Fonar' et al., 1999), which shows extended intermolecular hydrogen bonding. As part of this study, we have redetermined the structure of the title compound in order to improve on earlier structure determinations. Unexpectedly, the X-ray analysis revealed a new monoclinic (space group P2₁/c) polymorph of the title compound, (I), which is the subject of this communication.

The centrosymmetric formula unit of (I) is shown in Fig. 1. The slightly distorted octahedron of GeF₆²⁻ is characterized by Ge—F distances in the range 1.746 (1)–1.825 (1) Å and F—Ge—F angles that deviate slightly (3°) from the right and open angles; the geometry of the anion coincides with the previously reported data (Fonar' et al., 1999; Simonov et al., 1998). The fourfold protonated macrocyclic tetraamine cation, [H₄(C₁₆H₃₆N₄)]⁴⁺, resides on the inversion center, ?and the first coordination sphere of this cation includes two GeF₆²⁻ anions, which are related by the inversion centers via multiple N—H···F hydrogen bonds, and two O1w water molecules. Atom F4 bridges N1 and N4 atoms of the basic macrocycle via two N—H···F hydrogen bonds [N1···F4 = 3.061 (2) and N4···F4 = 2.771 (2) Å]; the same N atoms are also bound via atoms F2 and F6 [N1···F6 = 2.988 (2) and N4···F2 = 2.948 (2) Å]. Atom F2 links basic and center-of-symmetry-related neighboring macrocycles arranged along c axis [N1···F2(-x + 1, −y + 1, −z + 1) = 2.894 (2) Å].

Water molecule O2w has no direct contacts with the macrocycle but is involved in an interesting negatively charged zigzag chain, which develops along the c direction in the unit cell and combines inorganic species, GeF₆²⁻ anions and water molecules (Fig. 2). In this chain, O2w acts as a double hydrogen-bond donor and bridges two GeF₆²⁻ anions related by the glide plane [O2w···F3 = 2.795 (2) Å and O2w···F1(x, −y + 3/2, z − 1/2) = 2.739 (2) Å]. In the function of double acceptor, each O2w water molecule bridges O1w molecules [O1w···O2w(-x, y − 1/2, −z + 1/2) = 2.911 (2) Å and O1w···O2w(-x, −y + 1, −z) = 2.820 (2) Å. Thus, the alternating water molecules themselves form chains. These chains are further complicated by GeF₆²⁻ anions, attached to O2w molecules in such a way that each anion and three water molecules form a ten-membered cage closed by four hydrogen bonds [R₄⁴(10) in graph-set notation; Etter, 1990]. The above-mentioned N–H^···F and N–H^···O hydrogen bonds between the negatively charged chains and positively charged macrocycles combine the components into three-dimensional network, in which the inorganic chains alternate with the rows of macrocyclic cations (Fig. 2).

In the previously reported triclinic polymorph of the title compound (Fonar' et al., 1999), the nearest macrocycle's environment remains the same, while the hydrogen-bonding motifs that consolidate the components into a three-dimensional network differ from (I) (Fig. 3). Two GeF₆²⁻ anions and two O2w water molecules related by the inversion center are combined into heterotetramers [R₄⁴(12)]. These alternate with the macrocyclic cations in chains propagated along the c direction in the unit cell. These chains are further combined in layers arranged parallel to the ac plane via two O1w water molecules related via a center-of-symmetry. Water molecules are themselves organized in a four-membered linear association?, distinct from the infinite water chains in (I). Along the b direction, the above-mentioned layers are joined into three-dimensional network through N—H···O and N—H···F hydrogen bonds.

S2. Experimental

To a solution of rac-5,7,7,12,12,14-hexamethyl-1,4,8,1 1-tetraazacyclotetradecane (1 Mmol) in methanol (10 ml), a solution of H₂GeF₆ (3M in 1.5 ml) was added, and the mixture was boiled on a water bath. The resulting clear solution was slowly reduced in volume by evaporating the solvent at room temperature [m.p. of (I) is 343 K]. Analysis; found: C 24.39, H 6.28, F 36.01, N 7.26%; C₁₆H₄₈F₁₂Ge₂N₄O₄ requires: C 24.53, H 6.17, F 35.48, N 7.15%.

S3. Refinement

An absorption correction was applied according to the semi-empirical method of North et al. (1968). The coordinates of H atoms attached to atoms N1 and N4 and of water H atoms were determined from a difference map and were refined isotropically subject to a DFIX restraint. All other H atoms were treated as riding.

Computing details

Data collection: LEHMAN (Lehman & Larsen, 1974); cell refinement: BELLETTI (Belletti, 1996); data reduction: LEHMAN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. A view of the structure of (I). Displacement ellipsoids are drawn at the 50% probability level, and only the asymmetric unit is numbered.
	Fig. 2. Part of the crystal structure of (I), showing the inorganic anionic chains, formed by hydrogen-bonded anions and water molecules, that alternate with macrocyclic cations. For the sake of clarity, H atoms bonded to C atoms have been omitted.
	Fig. 3. Part of the crystal packing for the triclinic polymorph. For the sake of clarity, H atoms bonded to C atoms have been omitted.

rac-5,7,7,12,12,14-hexamethyl- 1,4,8,11-tetraazoniacyclotetradecane bis(hexafluorogermanate) tetrahydrate

Crystal data

(C16H40N4)[GeF6]2·4H2O	F(000) = 752
Mr = 733.76	Dx = 1.720 Mg m^−3
Monoclinic, P21/c	Melting point: 70 K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 9.5650 (19) Å	Cell parameters from 24 reflections
b = 16.522 (3) Å	θ = 5.6–16.2°
c = 9.0210 (18) Å	µ = 2.23 mm^−1
β = 96.28 (3)°	T = 293 K
V = 1417.1 (5) Å^3	Plate, white
Z = 2	0.25 × 0.20 × 0.20 mm

Data collection

Phillips PW1100 four-circle diffractometer	3251 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.015
Graphite monochromator	θmax = 30.0°, θmin = 3.2°
ω–2θ scans	h = 0→13
Absorption correction: empirical (using intensity measurements) North et al. (1968)	k = −23→0
Tmin = 0.606, Tmax = 0.664	l = −12→12
4350 measured reflections	3 standard reflections every 100 reflections
4137 independent reflections	intensity decay: 0.1%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.028	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.072	w = 1/[σ^2(Fo^2) + (0.0437P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.95	(Δ/σ)max = 0.002
4137 reflections	Δρmax = 0.65 e Å^−3
208 parameters	Δρmin = −0.62 e Å^−3
4 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0035 (6)

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
N1	0.65202 (15)	0.48758 (9)	0.28844 (16)	0.0170 (3)
H1N	0.665 (2)	0.4808 (14)	0.377 (3)	0.038 (7)*
H2N	0.583 (2)	0.5204 (12)	0.273 (2)	0.019 (5)*
C2	0.61510 (18)	0.40828 (10)	0.21150 (19)	0.0201 (3)
H2A	0.6883	0.3692	0.2423	0.024*
H2B	0.6135	0.4159	0.1047	0.024*
C3	0.47415 (18)	0.37364 (10)	0.24386 (18)	0.0209 (3)
H3A	0.4769	0.3154	0.2307	0.025*
H3B	0.4630	0.3839	0.3478	0.025*
N4	0.34695 (15)	0.40574 (9)	0.15045 (16)	0.0176 (3)
H3N	0.272 (3)	0.3778 (13)	0.180 (3)	0.031 (6)*
H4N	0.339 (2)	0.4523 (15)	0.173 (2)	0.029 (6)*
C5	0.34726 (18)	0.40030 (10)	−0.01641 (17)	0.0174 (3)
H5	0.4316	0.4279	−0.0431	0.021*
C51	0.3563 (2)	0.31189 (12)	−0.0614 (2)	0.0343 (5)
H51A	0.4383	0.2877	−0.0084	0.051*
H51B	0.3624	0.3084	−0.1667	0.051*
H51C	0.2738	0.2837	−0.0376	0.051*
C6	0.21803 (17)	0.44708 (10)	−0.08745 (18)	0.0188 (3)
H6A	0.2103	0.4961	−0.0298	0.023*
H6B	0.1356	0.4145	−0.0754	0.023*
C7	0.21032 (17)	0.47177 (10)	−0.25352 (18)	0.0185 (3)
C71	0.09110 (19)	0.53334 (12)	−0.2851 (2)	0.0312 (4)
H71A	0.0945	0.5563	−0.3824	0.047*
H71B	0.1017	0.5755	−0.2116	0.047*
H71C	0.0023	0.5068	−0.2811	0.047*
C72	0.1857 (2)	0.40094 (12)	−0.3625 (2)	0.0291 (4)
H72A	0.1058	0.3702	−0.3390	0.044*
H72B	0.2674	0.3668	−0.3543	0.044*
H72C	0.1685	0.4213	−0.4624	0.044*
Ge1	0.310989 (19)	0.621276 (10)	0.316046 (19)	0.01870 (7)
F1	0.24643 (18)	0.65746 (9)	0.48029 (16)	0.0585 (4)
F2	0.29704 (16)	0.52018 (7)	0.38974 (14)	0.0471 (4)
F3	0.13940 (14)	0.61257 (9)	0.22150 (18)	0.0503 (4)
F4	0.38129 (13)	0.57228 (7)	0.15877 (12)	0.0336 (3)
F5	0.32908 (15)	0.71764 (7)	0.24103 (17)	0.0474 (4)
F6	0.48772 (15)	0.62380 (10)	0.40165 (17)	0.0563 (4)
O1W	0.12041 (17)	0.31098 (10)	0.20649 (19)	0.0376 (4)
H1W	0.077 (2)	0.3026 (15)	0.283 (2)	0.044 (7)*
H2W	0.067 (2)	0.2972 (16)	0.135 (2)	0.046 (8)*
O2W	0.03232 (17)	0.74663 (11)	0.05757 (19)	0.0397 (4)
H3W	0.068 (3)	0.7104 (14)	0.109 (3)	0.054 (9)*
H4W	0.098 (3)	0.7706 (19)	0.022 (4)	0.088 (12)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0179 (7)	0.0173 (7)	0.0154 (7)	−0.0014 (5)	0.0004 (5)	0.0021 (5)
C2	0.0212 (8)	0.0171 (7)	0.0211 (8)	−0.0001 (6)	−0.0015 (6)	−0.0013 (6)
C3	0.0255 (8)	0.0188 (8)	0.0174 (7)	−0.0044 (7)	−0.0020 (6)	0.0050 (6)
N4	0.0204 (7)	0.0162 (6)	0.0162 (6)	−0.0030 (5)	0.0026 (5)	−0.0006 (5)
C5	0.0192 (8)	0.0196 (7)	0.0137 (7)	0.0012 (6)	0.0032 (6)	0.0029 (6)
C51	0.0517 (13)	0.0254 (9)	0.0247 (9)	0.0143 (9)	−0.0006 (9)	−0.0065 (7)
C6	0.0181 (7)	0.0201 (8)	0.0183 (7)	0.0001 (6)	0.0030 (6)	0.0026 (6)
C7	0.0158 (7)	0.0200 (8)	0.0189 (8)	−0.0027 (6)	−0.0012 (6)	0.0044 (6)
C71	0.0179 (8)	0.0337 (10)	0.0408 (11)	0.0030 (7)	−0.0024 (8)	0.0146 (9)
C72	0.0348 (10)	0.0290 (10)	0.0222 (8)	−0.0117 (8)	−0.0026 (7)	−0.0002 (7)
Ge1	0.02193 (10)	0.01746 (10)	0.01710 (9)	0.00349 (7)	0.00387 (6)	0.00024 (7)
F1	0.0845 (12)	0.0531 (9)	0.0435 (8)	0.0186 (8)	0.0328 (8)	−0.0117 (7)
F2	0.0837 (10)	0.0255 (6)	0.0368 (7)	0.0096 (6)	0.0277 (7)	0.0138 (5)
F3	0.0231 (6)	0.0586 (9)	0.0663 (10)	−0.0104 (6)	−0.0080 (6)	0.0156 (7)
F4	0.0524 (7)	0.0281 (6)	0.0237 (5)	−0.0062 (5)	0.0192 (5)	−0.0048 (5)
F5	0.0588 (9)	0.0199 (6)	0.0646 (9)	−0.0062 (6)	0.0111 (7)	0.0078 (6)
F6	0.0339 (7)	0.0848 (12)	0.0458 (8)	0.0079 (7)	−0.0159 (6)	−0.0109 (8)
O1W	0.0339 (8)	0.0413 (9)	0.0385 (9)	−0.0119 (7)	0.0078 (7)	0.0017 (7)
O2W	0.0311 (8)	0.0450 (10)	0.0423 (9)	−0.0011 (7)	0.0008 (7)	0.0122 (8)

Geometric parameters (Å, º)

N1—C2	1.506 (2)	C6—H6B	0.9700
N1—C7^i	1.541 (2)	C7—C72	1.530 (2)
N1—H1N	0.81 (2)	C7—C71	1.531 (2)
N1—H2N	0.85 (2)	C7—N1^i	1.541 (2)
C2—C3	1.522 (2)	C71—H71A	0.9600
C2—H2A	0.9700	C71—H71B	0.9600
C2—H2B	0.9700	C71—H71C	0.9600
C3—N4	1.499 (2)	C72—H72A	0.9600
C3—H3A	0.9700	C72—H72B	0.9600
C3—H3B	0.9700	C72—H72C	0.9600
N4—C5	1.508 (2)	Ge1—F5	1.7459 (12)
N4—H3N	0.92 (2)	Ge1—F1	1.7703 (13)
N4—H4N	0.80 (2)	Ge1—F3	1.7708 (14)
C5—C51	1.521 (2)	Ge1—F6	1.7805 (15)
C5—C6	1.537 (2)	Ge1—F2	1.8081 (12)
C5—H5	0.9800	Ge1—F4	1.8246 (11)
C51—H51A	0.9600	O1W—H1W	0.854 (16)
C51—H51B	0.9600	O1W—H2W	0.814 (16)
C51—H51C	0.9600	O2W—H3W	0.811 (17)
C6—C7	1.547 (2)	O2W—H4W	0.835 (18)
C6—H6A	0.9700
C2—N1—C7^i	116.57 (13)	C5—C6—H6B	107.5
C2—N1—H1N	109.9 (17)	C7—C6—H6B	107.5
C7^i—N1—H1N	102.6 (16)	H6A—C6—H6B	107.0
C2—N1—H2N	109.9 (13)	C72—C7—C71	109.24 (15)
C7^i—N1—H2N	110.7 (13)	C72—C7—N1^i	106.08 (14)
H1N—N1—H2N	106 (2)	C71—C7—N1^i	107.94 (14)
N1—C2—C3	113.99 (14)	C72—C7—C6	114.09 (14)
N1—C2—H2A	108.8	C71—C7—C6	108.12 (15)
C3—C2—H2A	108.8	N1^i—C7—C6	111.20 (13)
N1—C2—H2B	108.8	C7—C71—H71A	109.5
C3—C2—H2B	108.8	C7—C71—H71B	109.5
H2A—C2—H2B	107.7	H71A—C71—H71B	109.5
N4—C3—C2	116.15 (13)	C7—C71—H71C	109.5
N4—C3—H3A	108.2	H71A—C71—H71C	109.5
C2—C3—H3A	108.2	H71B—C71—H71C	109.5
N4—C3—H3B	108.2	C7—C72—H72A	109.5
C2—C3—H3B	108.2	C7—C72—H72B	109.5
H3A—C3—H3B	107.4	H72A—C72—H72B	109.5
C3—N4—C5	116.73 (13)	C7—C72—H72C	109.5
C3—N4—H3N	105.7 (14)	H72A—C72—H72C	109.5
C5—N4—H3N	110.3 (15)	H72B—C72—H72C	109.5
C3—N4—H4N	107.0 (15)	F5—Ge1—F1	94.30 (7)
C5—N4—H4N	108.7 (15)	F5—Ge1—F3	90.76 (7)
H3N—N4—H4N	108 (2)	F1—Ge1—F3	92.34 (8)
N4—C5—C51	109.27 (13)	F5—Ge1—F6	90.98 (7)
N4—C5—C6	107.27 (13)	F1—Ge1—F6	91.75 (8)
C51—C5—C6	115.99 (15)	F3—Ge1—F6	175.42 (7)
N4—C5—H5	108.0	F5—Ge1—F2	177.94 (6)
C51—C5—H5	108.0	F1—Ge1—F2	87.58 (7)
C6—C5—H5	108.0	F3—Ge1—F2	90.02 (7)
C5—C51—H51A	109.5	F6—Ge1—F2	88.10 (7)
C5—C51—H51B	109.5	F5—Ge1—F4	92.44 (6)
H51A—C51—H51B	109.5	F1—Ge1—F4	173.00 (6)
C5—C51—H51C	109.5	F3—Ge1—F4	89.45 (7)
H51A—C51—H51C	109.5	F6—Ge1—F4	86.24 (7)
H51B—C51—H51C	109.5	F2—Ge1—F4	85.66 (6)
C5—C6—C7	119.17 (14)	H1W—O1W—H2W	106 (2)
C5—C6—H6A	107.5	H3W—O2W—H4W	107 (3)
C7—C6—H6A	107.5
N1—C2—C3—N4	83.49 (18)	C5—C6—C7—N1^i	−48.63 (19)
C2—C3—N4—C5	54.5 (2)	C6—C7—N1^i—C2^i	−64.22 (18)
C3—N4—C5—C6	−172.17 (13)	C7—N1^i—C2^i—C3^i	176.76 (13)
N4—C5—C6—C7	163.92 (14)

Symmetry code: (i) −x+1, −y+1, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H2N···F4	0.85 (2)	2.26 (2)	3.061 (2)	157.2 (18)
N1—H2N···F6	0.85 (2)	2.31 (2)	2.988 (2)	137.0 (17)
N1—H1N···F2^ii	0.81 (2)	2.09 (2)	2.894 (2)	172 (2)
N4—H3N···O1W	0.92 (2)	1.86 (2)	2.764 (2)	169 (2)
N4—H4N···F4	0.80 (2)	2.03 (2)	2.771 (2)	154 (2)
N4—H4N···F2	0.80 (2)	2.33 (2)	2.948 (2)	135 (2)
O1W—H1W···O2W^iii	0.85 (2)	2.09 (2)	2.911 (2)	162 (2)
O1W—H2W···O2W^iv	0.81 (2)	2.02 (2)	2.820 (3)	169 (3)
O2W—H3W···F3	0.81 (2)	1.99 (2)	2.795 (2)	173 (3)
O2W—H4W···F1^v	0.84 (2)	1.92 (2)	2.739 (2)	166 (3)

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