Change of the crown ether geometry by complexation in tetrapyrrolidinyl PNP-lariat ether. Crystal structure of the complex of tetrapyrrolidinyl PNP-lariat ether with sodium iodide

www.elsevier.nl/locate/ica Inorganica Chimica Acta 321 (2001) 185– 192

Note

Change of the crown ether geometry by complexation in tetrapyrrolidinyl PNP-lariat ether. Crystal structure of the complex of tetrapyrrolidinyl PNP-lariat ether with sodium iodide Rafal Kruszynski a, Tadeusz J. Bartczak a,*, Krystyna Brandt b, Dariusz Lach b a

X-ray Crystallography Laboratory, Institute of General and Ecological Chemistry, Technical Uni6ersity of Ło´dz´, ul. Zeromskiego 116, 90 -924 Lodz, Poland b Institute of Polymer Chemistry, Polish Academy of Science, Zabrze, Poland Received 7 February 2001; accepted 4 June 2001

Abstract The crystal and molecular structure of the title compound, C24H50IN7NaO6P3, crystallizing in P1( space group has been determined by X-ray crystallography. The oxygen atoms of the crown ether exist in an almost ideal envelope conformation. The inorganic cyclophosphazene P3N3 ring has a non-planar envelope conformation. All endocyclic PN bond lengths are equal within experimental error with the mean value of 1.585(5) A, . The Na+ ion is coordinated by oxygen atoms from the crown ether and the water molecule but not by the cyclophosphazene nitrogen atom. The OPNPO part of the 16-membered ring is flexible. The crown ether part of the 16-membered ring adopts approximately D3d symmetry. Complex mean cavity radii are close to effective ionic radii. There is no coordination bond between nitrogen and metals with effective ionic radii smaller than 2.3 A, . © 2001 Elsevier Science B.V. All rights reserved. Keywords: Cyclophosphazenes; Lariat ethers; Conformation of macrocycle

1. Introduction Ligand flexibility is a major fact in complexation by cryptands [1]. This depends largely on neutralizing the charge on the metal, which requires an appropriate number of donors in an appropriate topography. In flexible lariat ethers the carbon framework primarily maintains the connectivity relationship among the donors rather than imposing a rigid conformation or steric bias on the system [2]. The pure crown ethers coordinating hard cations such as potassium ion generally adopt approximate D3d conformation [3]. This symmetry is best monitored by the OCCO torsion angle, which, in the ideal D3d symmetric conformation, should display alternating * Corresponding author. Tel.: + 48-42-631-3137; fax: +48-42-6313103. E-mail address: [email protected] (T.J. Bartczak).

values of 9 60°, and by the COCC angle, which should be 9180° [4,5]. In the PNP-lariat ethers this geometry is always more or less distorted, because the 16-membered ring is built from two parts. One, containing cyclophosphazene and two, the oxygen atoms are stiff as a consequence of the steric constraints caused by the geometry of the P3N3 ring and acting as an anchor for the second flexible organic part of the 16-membered ring [6]. Preliminary complexation studies by means of simple chromatographic tests have allowed selecting the tetrapyrrolidinyl cyclophosphazene PNP-crown derivative I as the most promising PNP-lariat ether ligand exhibiting a wide spectrum of complexation abilities [7] (Fig. 1). In the case of I, there are three possible structural units capable of taking part in binding metal cations: (a) polyether oxygen donors of the macrocyclic PNP-

0020-1693/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 0 - 1 6 9 3 ( 0 1 ) 0 0 5 1 2 - 6

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crown skeleton; (b) exocyclic nitrogen atoms of the pyrrolidinyl substituents (side arms); and (c) endocyclic

Fig. 1. Investigated ligand. Table 1 Crystallographic data and structure refinement parameters for IV Empirical formula Formula weight Temperature (K) Wavelength (A, ) Crystal system Space group Unit cell dimensions a (A, ) b (A, ) c (A, ) h (°) i (°) k (°) V (A, 3) Z Dcalc (Mg m−3) Absorption coefficient (mm−1) F(000) Crystal size (mm) q Range for data collection (°) Index ranges Reflections collected/unique Completeness to q =25.05 (%) Refinement method Max/min transmission Data/restraints/parameters Goodness-of-fit on F 2 Final R indices [I\2|(I)] R indices (all data) Largest difference peak and hole (e A, −3)

C24H50IN7NaO6P3 775.51 293(2) u (Mo Ka)= 0.71073 triclinic P1( 9.1794(6) 13.8879(9) 14.6150(9) 89.321(6) 73.642(7) 85.942(6) 1783.2(2) 2 1.444 1.090 800 0.26×0.14×0.07 3.43–25.05 −105h510, −165k516, 051517 6287/6287 99.7 full-matrix least-squares on F2 0.928, 0.765 6287/0/380 1.070 R1 = 0.0605, wR2 = 0.1443 R1 = 0.0845, wR2 = 0.1608 0.857 and −0.653

nitrogen atoms of the cyclophosphazene ring [7]. The latter are known to display complexation ability; in particular, toward transition metal ions when strongly electron-donating substituents are linked to phosphorus atoms, enhancing ring nitrogen atom basicity [8]. The poor donor properties of nitrogen relative to oxygen toward alkali metal cations have been previously established [9– 11], but both Na+ and K+ present hard types of cations, which can interact electrostatically with the oxygen and nitrogen donor atoms. The aim of our study was to determine the X-ray crystal structure for the complex of sodium iodide (IV) with I and to compare the macrocycle geometry with that of uncomplexed ligand I [7] and complexes with potassium iodide (II [7] and III [12]). Solid state studies, if not directly applicable to the solution phase, are very important in this area, as they involve the key molecules (host and guest), and can confirm directly the type of cation binding [13]. For nitrogen–pivot lariat ethers the solid-state work confirmed all that had been learned from the solution studies.

2. Experimental

2.1. Synthesis Ligand I was synthesized according to Ref. [14]. The complex with sodium iodide was obtained by dissolution of equimolar amounts of the crystalline ligand (0.0609 g, 0.1 mmol) and NaI (0.0150 g, 0.1 mmol) in methanol (5 cm3) in an open vessel and allowed to evaporate. After that product was recrystallized from acetonitrile (12 cm3) colorless crystals were obtained. Melting point: 403.12(4) K (one endothermic peak on the differential scanning calorimetry (DCS) curve, with DH= 59.81 J g − 1). Free L exhibited a melting point at 382.36 K (DH = 28.3 J g − 1).

2.2. X-ray crystal structure analysis of compound IV A rectangular prism of IV of approximate dimensions 0.07× 0.14×0.26 mm was mounted on a KM-4CCD automatic diffractometer equipped with a CCD detector, and used for data collection. X-ray intensity data were collected with graphite monochromated Mo Ka radiation (u= 0.71073 A, ) at room temperature in the …-scan mode. A 22 s exposure time was used. A half of the Ewald sphere was collected. The unit cell parameters were determined from least-squares refinement of the setting angles of 2830 strongest reflections. Details concerning crystal data and refinement for IV are given in Table 1. Examination of two reference frames monitored after each 50 frames measured showed 2.11% loss of intensity. Decay correction coefficient was taken into ac-

R. Kruszynski et al. / Inorganica Chimica Acta 321 (2001) 185–192 Table 2 Selected bond distances (A, ) and bond angles (°) for IV

(1) Sodium en6ironment bond lengths Na(1)O(1) Na(1)O(2) Na(1)O(3) Na(1)O(4) Na(1)O(5) Na(1)O(10)

2.499(4) 2.456(4) 2.472(4) 2.458(4) 2.509(3) 2.342(5)

(2) Phosphazene ring bond lengths P(1)N(1) N(1)P(2) P(2)N(2) N(2)P(3) P(3)N(3) N(3)P(1)

1.599(4) 1.574(4) 1.601(4) 1.599(4) 1.583(4) 1.603(4)

(3) Phosphazene bond lengths exocyclic to the P3N3 ring P(2)N(4) 1.625(4) P(1)N(5) 1.652(4) P(1)N(6) 1.629(4) P(3)N(7) 1.635(4) (4) Lariat ether bond lengths P(2)O(1) O(1)C(1) C(1)C(2) C(2)O(2) O(2)C(3) C(3)C(4) C(4)O(3) O(3)C(5) C(5)C(6) C(6)O(4) O(4)C(7) C(7)C(8) C(8)O(5) O(5)P(3)

1.609(3) 1.447(5) 1.493(7) 1.410(6) 1.438(6) 1.484(9) 1.422(7) 1.429(7) 1.470(9) 1.431(6) 1.427(6) 1.502(7) 1.437(6) 1.607(3)

(5) Bond angles within the P3N3 ring P(1)N(1)P(2) N(1)P(2)N(2) P(2)N(2)P(3) N(2)P(3)N(3) P(3)N(3)P(1) N(3)P(1)N(1)

123.5(2) 117.0(2) 118.6(2) 116.9(2) 122.3(2) 115.4(2)

(6) Bond angles exocyclic to the P3N3 ring N(1)P(1)N(6) N(3)P(1)N(6) N(1)P(1)N(5) N(3)P(1)N(5) N(6)P(1)N(5) N(1)P(2)O(1) N(2)P(2)O(1) N(1)P(2)N(4) N(2)P(2)N(4) O(1)P(2)N(4) N(3)P(3)O(5) N(2)P(3)O(5) N(3)P(3)N(7) N(2)P(3)N(7) O(5)P(3)N(7)

113.7(2) 106.5(2) 105.7(2) 113.4(2) 101.4(2) 111.8(2) 102.18(18) 108.7(2) 113.7(2) 102.33(19) 112.1(2) 102.44(18) 108.6(2) 112.8(2) 103.04(18)

count during the data reduction. A colorless, transparent crystal of IV used for data collection became

187

slightly brown. Lorentz–polarization correction was applied to the intensity data. Numerical absorption correction was used. The maximum and minimum transmission factors were 0.928 and 0.765. The structure of IV was solved by direct methods and subsequently completed by the difference Fourier recycling. All the non-hydrogen atoms were refined anisotropically using full-matrix least-squares technique on F 2. All the hydrogen atoms were found from difference Fourier synthesis after four cycles of anisotropic refinement, and refined as ‘riding’ on the adjacent carbon atom with the individual isotropic temperature factor equal to 1.2 times the value of the equivalent temperature factor of the parent carbon atom. A standard bond length (CH = 0.97 A, ) and appropriate geometry have been assumed. Hydrogen atom positions were idealized after each cycle of refinement. The solution and refinements were performed with SHELXS-97 [15] and SHELXL-97 [16]. The graphical manipulations were performed using the XP routine of the SHELXTL [17] and ORTEP [18]. Atomic scattering factors were those incorporated in the computer programs. Interatomic bond distances and bond angles are listed in Table 2.

3. Results and discussion

3.1. Crystallographic description of compound IV A perspective view of the structure together with the atom-numbering scheme is shown in Fig. 2, hydrogen atoms being omitted for clarity. The structure is plotted with 50% probability of thermal ellipsoids. The pyrrolidine rings indicated by N(4), N(5) and N(6) atoms show some symptoms of disorder. This affects the bond lengths, C(10)C(11) =1.387(11) A, , C(15)C(16) = 1.428(9) A, and C(18)C(19) =1.381(12) A, . In addition these parts of the molecule exhibit rather large thermal

Fig. 2. The molecular conformation of IV with atom numbering plotted with 50% probability of thermal ellipsoids. Hydrogen atoms being omitted for clarity.

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motion (Fig. 2). All attempts to find the model of this disorder were unsuccessful. One hydrogen atom of water molecule coordinating sodium cation also shows signs of disorder, which was seen on the difference Fourier synthesis map. This may be explained by weak hydrogen bonds existing in the structure. The part of the molecule containing cyclotriphosphazene, crown ether and two pyrrolidine rings indicated by N(4), N(7) atoms has a pseudo-plane of symmetry passing through P(1), N(2) and O(3) atoms. The remaining two pyrrolidine rings are tied by pseudotwofold axis parallel to the cyclophosphazene ring. The 16-membered ring exists in the conformation of a slightly distorted crown, which is illustrated by the torsion angles. All absolute values of alternating OCCO torsion angles are close to the mean value of 59.8(7)°, and all COCC torsion angles are similar too, with a mean value of 174.6(5)° (for details see Table 4). It suggests a crown ether geometry close to ideal D3d. All the ether oxygen atoms are directed into the interior of the ring. These oxygen atoms exist in envelope conformation with O(3) at the flap. The maximum deviations from calculated least-squares plane through atoms O(4)O(5)O(1)O(2) is for O(1) atom and equal to − 0.0316(19)°. Flapping atom O(3) deviates from the described least-squares plane by − 0.817(6) A, and creates an angle of 29.1(2)° between least-squares planes O(4)O(5)O(1)O(2) and O(2)O(3)O(4). The cyclophosphazene ring is distorted from planarity, and exists in conformation of almost ideal envelope with N(2) at the flap. The largest deviation from the least-squares plane through P(3), N(3), P(1), N(1), and P(2) is −0.047(2) A, for N(3), and the flapping atom N(2) deviates from these planes by −0.305(4) A, , which makes the angle between the P(3)N(3)P(1)N(1)P(2) and P(2)N(2)P(3) planes equal to 22.7(3)°. In the case of the least-squares plane calculated through all cyclophosphazene atoms, a maximum deviation of − 0.155(2) A, occurs for the N(2) atom. The endocyclic PN bond lengths are not equal within experimental error (see Table 2). This may suggest that ‘island’ delocalization of electrons [19], typical for simple cyclotriphosphazenes [20], in this case is strongly disturbed. The cyclophosphazene ring forms an angle 71.75(5)° with the 16-membered ring [maximum deviation from the plane is for N(2) atom with value − 0.8334(33) A, ] and 66.59(6)° with ‘crown’ ring plane defined by the oxygen and carbon atoms. The maximum deviation from this ring is significantly smaller than that in the 16-membered ring and it counts 0.403(5) A, for C(8). The cyclophosphazene ring forms the angles 63.8(3), 80.5(3), 79.5(3) and 75.7(2)° with the five-membered pyrrolidine rings indicated by N(4), N(5), N(6) and N(7) atoms, respectively. The geometry of all phosphorus atoms is distorted tetrahedron. For

P(1) it follows from rigid cyclophosphazene and steric constrains imposed by large pyrrolidine rings. The distortion of environments of P(2) and P(3) atoms is mostly caused by the inflexible cyclophosphazene ring, pyrrolidine rings and imposed by insertion of sodium ion into the crown ether, but not by the crown ether itself [12]. Two weak hydrogen bonds can be detected in the structure, one intermolecular O(10)− H(10A)··· I(1 c a) with donor–acceptor distance of 3.508(4) A, and angle 170.4° [I(1 ca) atom generated by −x+1, − y+ 1, − z+ 1 symmetry transformation] and one intramolecular O(10)− H(10C)···N2 with a donor–acceptor distance of 2.903(5) A, and angle 148.5°. There is a possibility of existence of three more weak hydrogen bonds, intramolecular C(1)− H(1A)···N(4), O(10)− H(1OC)···O(5) and intermolecular C(3)− H(3A)··· O(10c a) [O(10 c a) atom generated by −x+2, − y+ 2, − z + 1 symmetry transformation] with donor–acceptor distances 3.060(7), 3.256 (6), 3.024(6) A, and angles 105.7, 143.9, 105.9°, respectively. It was expected that the sodium ion, which is a hard cation, would coordinate seven oxygen atoms (five crown ether oxygen atoms and two water molecules, or five crown ether oxygen atoms, one cyclophosphazene nitrogen atom and one water molecule) [2,12,13,21]. The assumption that the N(2) atom coordinates to the sodium cation was rejected because of a large distance equal to 3.335(4) A, and in the molecule only one water molecule coordinating to the sodium cation was detected. There is no second expected water molecule. These can be explained by crystal packing (Fig. 3) which has an unusual short distance between Na(1 ca) and C(3), equal to 4.181(7) A, . It can be supposed that there is the same kind of interaction between Na(1 ca) and H(3B) because of a short (3.26 A, ) distance [Na(1 c a) atom generated by − x+ 2, −y+2, − z+ 1 symmetry transformation]. This may be similar to weak hydrogen bonds observed for transition metals acting as acceptors in low oxidation states [22].

3.2. Lariat ether Alkali metal cations (K+, Na+) form crown etherlike complexes with tetrapyrrolidinyl PNP-crown, in the case of the ‘perching’ complex with potassium ion with the co-participation of a water molecule [7,12]. Only oxygen donors are involved in the coordination of these hard metal cations. Complexation of K+, stabilized by one water molecule, which is non-complementary to the PNP-crown cavity, involves a severe distortion of some ligand bonds from the favorable conformation [7]. To release the steric strain there is a great tendency to co-opt to the complex the auxiliary oxygen donors from the adjacent water molecules. The participation of the nitrogen donors from the pyrrolidinyl substituents adjacent to the PNP-crown

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substituent electronic interactions has been also previously demonstrated for tetraaziridinyl cyclophosphazenes with arylenediamino and arylendioxy substituents [24]. While the relatively soft nitrogen atom of pyrrolidinyl groups is not very prone to complex with the hard cation, that adjacent to the macrocycle water molecule plays a part of pseudo-side arm co-participating in the complexation of the cation with five polyether oxygens to meet the respective optimum coordination number (i.e. seven for potassium cation [12]). Hydrogen bonding of the nitrogen atom belonging of the PNP-macrocycle to the co-complexing water molecule in IV also confirms the side arm role of this water molecule. Taking into account the above considerations the pyrrolidinyl-PNP-crown can be regarded as a lariat ether, in which side arms play an indirect (auxiliary) part in the complexation, enhancing the coordinative ability of the macrocyclic oxygen donors by additional electron flow from electron-donating substituent toward the PNP-crown macrocycle.

3.3. Lariat ether geometry

Fig. 3. Crystal packing of IV. Distance between Na(1 ca) and C(3) indicated by dashed line. Table 3 Torsion angles (°) in PNP-lariat ether I [77] and its complexes with KI·H2O monohydrate II [77], KI·2H2O monohydrate III [72] and NaI·H2O IV (this work) Torsion angle a

I

P(3)N(2)P(2)O(1) N(2)P(2)O(1)C(1) P(2)O(1)C(1)C(2) O(1)C(1)C(2)O(2) C(1)C(2)O(2)C(3) C(2)O(2)C(3)C(4) O(2)C(3)C(4)O(3) C(3)C(4)O(3)C(5) C(4)O(3)C(5)C(6) O(3)C(5)C(6)O(4) C(5)C(6)O(4)C(7) C(6)O(4)C(7)C(8) O(4)C(7)C(8)O(5) C(7)C(8)O(5)P(3) C(8)O(5)P(3)N(2) O(5)P(3)N(2)P(2)

−135.6(4) −95.0(3) 80.3(8) 169.4(5) −118(1) 173.3(4) −60(2) 62.5(8) −142(2) 179.4(6) −94(2) 179.8(6) 96(2) −68.4(8) −167(1) 167.0(7) 88(2) −95.4(7) 66(2) −65.5(7) −158(1) 174.9(5) 167.8(9) −172.4(6) −176.1(6) 60.3(9) 122.1(7) 125.6(6) −64.5(7) 176.2(5) 141.7(4) 104.9(3)

a

II

III

IV

−109.1(4) 175.0(5) −161.3(5) 61.4(7) 172.6(6) −179.9(6) −65.6(7) 175.5(6) −173.0(6) 67.2(8) −175.4(7) −177.0(6) −62.0(8) 161.0(5) 176.1(5) 112.4(4)

−96.9(3) −176.9(4) 160.4(4) 58.6(6) 178.4(4) −178.9(5) −60.3(6) 173.5(5) −167.3(5) 61.7(7) 174.1(5) 175.4(5) −58.6(5) −155.1(3) 176.8(4) 94.1(3)

The PNP-lariat ether conformation is best described by the torsion angles (Table 3). The absolute value of the PNPO torsion angle for compounds I–IV changes from 94.1 to 141.7°, which means that the OPNPO part of the 16-membered ring is rather flexible than stiff. Significant differences between this range and values 960 and 9180° cause distortion in the PNP-lariat ether conformation from ideal D3d geometry but allow to the existence of partial D3d symmetry in the crown ether. Fig. 4 clearly shows that ordering of the crown ether increase in the sequence IB IIB IIIB IV, and for III, IV shows almost D3d symmetry. Torsion angles exactly determine the crown conformation, however, to simplify the comparison it is handy to use sp, sc 9 , ac 9 , ap notation [25], where sp indicates the range of torsion angles from − 30 to 30°, sc 9 indicates the range from 9 30 to 9 90°, ac 9 indicates the range from 9 90 to 9150°, ap indicates the range from 9 150 to 9180° and the superscript indicates the sign of the angle (Table 4). According to these notations it is easy to find that compounds III and IV have a pseudo-mirror plane and ether parts have rotation axis (ap sc+ ap ap sc− ap)2 (Fig. 4).

Atoms notation from current work.

3.4. Cryptand ca6ity structure in the coordination of metal cations seems to be limited not only by the donation of lone pair of electrons of pyrrolidinyl ring nitrogen atoms toward the PNP-macrocyclic nitrogen atom, but also by their N3P3 ring-mediated intersubstituent interactions with the polyether PNP-crown oxygen donors [23] and the overall PNP-crown geometry. The existence of similar inter-

The typical description of the structure of the PNPlariat ethers does not explain all the geometric properties of the crown ether. In the case of complexation, not only the conformation of the crown ether is very important, but also in addition it is necessary to determine precisely in which range it is possible to change the

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Table 4 Simplified notation of torsion angles in PNP-lariat ether I [77] and its complexes with KI·H2O monohydrate II [77], KI·2H2O monohydrate III [72] and NaI·H2O IV (this work) ac− ac− ac−

I II III, IV

sc+ ap ap

ac− ap ap

sc− sc+ sc+

ac− ap ap

ac− ap ap

ac+ sc− sc−

cryptand cavity size and geometry. Because the cryptand cavity is not planar, but has a three-dimensional geometry, one needs to use two different types of parameters. One is the simple description of lengths of cavity edges. The second one is asymmetry parameters introduced by Duax and Norton for the description of the steroid structures [26]. In our case these asymmetry parameters were calculated using the formulae:

DC2 =

D

sc+ ac− ap

ap ap ap

sc+ sc− sc+

ap ap ap

ap ap ap

ap sc+ sc−

ac+ ac+ ap

sc− ap ap

ac+ ac+ ac+

Data Centre, CCDC No. 157196 for compound IV. Copies of this information may be obtained free of charge from The Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (fax: + 44-1223-336-033; e-mail: [email protected] or www: http:// www.ccdc.cam.ac.uk)

m

% (ƒi −ƒ%i )2

i=1

m

D

for twofold axis, and

DCs =

m

% (ƒi − ƒ%i )2

i=1

m

for mirror plane, where m is the number of the symmetrical pairs of the torsion angles and ƒi and ƒ %i are values of the torsion angles taking signs into account. When the value of the asymmetry parameter approaches zero, the pseudo-plane and twofold axis of symmetry aim at respecting the ideal symmetry element. The calculated asymmetry parameters for the structures considered are given in Table 5, and placement of these are depicted in Fig. 5. According to the calculated values, I, III, IV exist in envelope conformation, and II in half-chair conformation. Crystal cavity size enlarge in the order IV, II, III, I, which agree with the calculated values of complex mean cavity radius R [1] (1.45(1), 1.48(1), 1.08(1) A, for II, III, IV, respectively). These R-values are close to effective ionic radii of sodium and potassium [27]. Complex mean cavity radius calculated for the hypothetical complex for which coordination of the nitrogen atom to the cation occurs has values 1.54(1), 1.56(1), 1.20(1) A, for II, III, IV, respectively. The difference between the R-values with and without NM+ bond can suggest that there is no coordination bond between the nitrogen and metals with effective ionic radii smaller than 2.3 A, .

4. Supplementary material Crystallographic data for the structural analysis have been deposited with the Cambridge Crystallographic

Fig. 4. Changing values of torsion angles in crown ether.

Table 5 Length of edges (A, ), torsion angles (°) and asymmetry parameters (°) of cryptand cavity in PNP-lariat ether I [77] and its complexes with KI·H2O monohydrate II [77], KI·2H2O monohydrate III [72] and NaI·H2O IV (this work)

Ca6ity edge O(1)O(2) O(2)O(3) O(3)O(4) O(4)O(5) O(5)O(1)

I

II

III

IV

3.042(20) 3.069(17) 2.880(13) 3.524(8) 4.725(7)

2.775(6) 2.821(6) 2.879(7) 2.808(6) 3.673(5)

2.788(7) 2.811(7) 2.802(8) 2.751(6) 3.929(6)

2.698(5) 2.738(5) 2.742(5) 2.726(4) 3.496(4)

a

Torsion angle a O(1)O(2)O(3)O(4) −22.2(6) 39.3(3) 23.0(3) 33.1(2) O(2)O(3)O(4)O(5) 9.8(6) −32.6(3) −23.3(3) −30.4(2) O(3)O(4)O(5)O(1) 1.3(4) 16.3(2) 14.0(2) 16.64(19) O(4)O(5)O(1)O(2) −11.8(3) 5.9(2) −1.3(2) 2.75(17) O(5)O(1)O(2)O(3) 22.2(5) −27.8(2) −12.2(2) −21.5(2) Asymmetry parameters DCs 1.4(4) DC2 9.5(6) a

9.4(3) 8.1(3)

Atoms notation from current work.

1.3(2) 10.0(3)

3.9(2) 11.7(2)

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Fig. 5. Placement of asymmetry parameters in lariat ether O atoms pentagon.

Acknowledgements This work was financed by statutory funds allocated by the State Committee for Scientific Research to the Institute of General and Ecological Chemistry, Technical University of Lodz. References [1] F. Mathieu, B. Metz, D. Moras, R. Weiss, J. Am. Chem. Soc. 100 (1978) 4412. [2] R.D. Gandour, F.R. Fronczek, V.J. Gatto, C. Minganti, R.A. Schultz, B.D. White, K.A. Arnold, D. Mazzocchi, S.R. Miller, G.W. Gokel, J. Am. Chem. Soc. 108 (1986) 4078. [3] K.M. Doxsee, H.R. Wierman, T.J.R. Weakley, J. Am. Chem. Soc. 114 (1992) 5165.

[4] E.L. Eliel, S.H. Wilen, Stereochemistry of Organic Compounds, John Wiley & Sons, Inc., New York, 1994, p. 83. [5] K.M. Doxsee, J.R. Hagadorn, T.J.R. Weakley, Inorg. Chem. 33 (1994) 2600. [6] K. Brandt, T. Kupka, J. Drozd, J.C. van de Grampel, A. Meetsma, A.P. Jekel, Inorg. Chim. Acta 228 (1995) 187. [7] K. Brandt, P. Seliger, A. Grzejdziak, T.J. Bartczak, R. Kruszynski, D. Lach, J. Silberring, Inorg. Chem. 40 (2001) 3704. [8] V. Chandrasekhar, K.R. Justin Thomas, Appl. Organomet. Chem. 7 (1993) 1 (review). [9] M.C. Day, J.H. Medley, N. Ahmad, Can. J. Chem. Soc. 61 (1983) 1719. [10] M. Shamispur, A.I. Popov, Inorg. Chim. Acta 43 (1980) 243. [11] R.A. Schultz, D.M. Dishong, G.W. Gokel, J. Am. Chem. Soc. 104 (1982) 625. [12] R. Kruszynski, T.J. Bartczak, K. Brandt, D. Lach, J. Coord. Chem., in press. [13] G.W. Gokel, Chem. Soc. Rev. (1992) 39.

192

R. Kruszynski et al. / Inorganica Chimica Acta 321 (2001) 185–192

[14] K. Brandt, I. Porwolik-Czomperlik, M. Siwy, T. Kupka, R.A. Shaw, D.B. Davies, R.A. Bartsch, J. Inclusion Phenom. Macrocyc. Chem. 35 (1999) 281. [15] G.M. Sheldrick, SHELXS-97, Program for the Solution of Crystal Structures, University of Go¨ ttingen, Go¨ ttingen, Germany, 1997. [16] G.M. Sheldrick, SHELXL-97, Program for the Refinement of Crystal Structures, University of Go¨ ttingen, Go¨ ttingen, Germany, 1997. [17] G.M. Sheldrick, Release 4.1 of SHELXTL-PC™ for Siemens Crystallographic Systems, May 1990, Siemens Analytical X-Ray Instruments Inc, 1990. [18] L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565. [19] M.J.S. Dewar, E.A.C. Lucken, M.A. Whitehead, J. Chem. Soc. (1960) 2423.

.

[20] T.S. Cameron, B. Borecka, W. Kwiatkowski, J. Am. Chem. Soc. 116 (1994) 1211. [21] R.D. Hancock, Pure Appl. Chem. 58 (1986) 1445. [22] G.R. Desiraju, T. Steiner, The Weak Hydrogen Bond, Oxford University Press, Oxford, 1999, p. 271. [23] Ch.W. Allen, D.E. Brown, S.D. Worley, Inorg. Chem. 39 (2000) 810 (and references therein). [24] K. Brandt, J. Mol. Struct. 243 (1991) 163. [25] A. Hazell, R.G. Hazell, M.F. Holm, L. Krogh, Acta Crystallogr., B 47 (1991) 234. [26] L. Duax, D.A. Norton, Atlas of Steroid Structure, vol. 1, IFI/Plenum, New York, 1975, pp. 16 – 22. [27] R.D. Shannon, Acta Crystallogr., A 32 (1976) 751 (and references therein).