Chiral Cryptates Derived from a Hexaazamacrocycle - The Journal of

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Chiral Cryptates Derived from a Hexa-azamacrocycle Aleksandra Gerus, Katarzyna #lepokura, Jaros#aw Panek, Aleksandra Turek, and Jerzy Lisowski J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.8b00670 • Publication Date (Web): 18 May 2018 Downloaded from http://pubs.acs.org on May 18, 2018

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The Journal of Organic Chemistry

Chiral Cryptates Derived from a Hexa-azamacrocycle.

Aleksandra Gerus, Katarzyna Ślepokura, Jarosław Panek, Aleksandra Turek and Jerzy Lisowski* Department of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland. *[email protected]

N

H N

N

H N

+2 N

H

H

X

N

N

N

N

N

N N

N

N X

N

ABSTRACT The

reactions

of

hexaazamacrocycle

1

with

2,6-bis(bromomethyl)pyridine

or

2,6-

bis[(tosyloxy)methyl)]pyridine in the presence of appropriate carbonates result in the formation of derivatives of cryptand 6 –

enantiopure azacryptates of sodium and potassium. Crystal

structures of these compounds indicate interaction of a metal ion with four pyridine nitrogen atoms and four tertiary amine atoms. The competition reactions monitored by NMR spectroscopy indicate preferential binding of Na+ over K+ as well as higher affinity of 6 for Na+ in comparison with the [2.2.1] cryptand.

The discoveries of cryptands by J. M. Lehn and others1 constitute one of the pillars of organic and supramolecular chemistry which has led to a variety of host molecules.2-4 The preorganized three-dimensional structures of cryptands lead to very strong and often selective metal binding (a phenomenon called the Cryptate Effect). The exceptional binding properties of these molecules 1 ACS Paragon Plus Environment

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towards alkali metal cations paved the way to unusual compounds such as alkalides and electrides5 and to applications such as phase transfer catalysis, separations and sensors. Cryptands are studied also in the context of medical applications, such as in vivo alkali metal cation sensing or delivery.6 Most of the cryptands, such as the archetypical bicylic [2.2.2] cryptand,7 are built predominantly of polyether fragments. The all-aza cryptands and cryptates are also known. For instance, the octaazacryptands based on the bipyridine or phenanthroline fragments developed by J. M. Lehn are excellent ligands for lanthanide(III) ions,3a, b and their luminescent properties have found application in biological assays. Azacryptands not only bind metal ions3 but also anions,4 while smaller-size azacryptands act as proton cages or proton sponges.8 N

NH

HN NH HN

N

1 N X

Br

X

2

3

X = Br

4

X = OTs

N N

N NH

NH N

N

5 N N

N

N

N

N

N

N

N

N

N

N

N

N

6

8

N N

N

N

N

N

N N

7

Scheme 1. Alkylation of the macrocyclic amine 1 leading to cryptand derivative 6 (24 h reflux in CH3CN, K2CO3 or Na2CO3 added as a base). 6 was obtained as sodium or potassium cryptate, 5, 7 and 8 were obtained as perchlorate or ethylsulfate salts after reactions with acids.

Although many cryptand systems have been synthesized, chiral, enantiopure cryptands are relatively rare.9 In this report we present the formation of enantiopure sodium and potassium octaazacryptates [Na+⊂ R-6]Br, [Na+⊂ S-6]Br, [K+⊂ R-6]Br and [K+⊂ R-6]OTs, based on the alkylation of enantiomers of chiral hexaazamacrocycle R-1 and S-1 (Scheme 1). We also report 2 ACS Paragon Plus Environment

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the formation of isomeric cryptand by-product 7, analogous semicryptand 5, and alkylated benzyl derivative 8 of the parent macrocycle 1. Macrocycle 1 can be synthesized in enantiopure form and it adopts a variety of helically twisted conformations both as a free ligand and in its metal complexes.10 Although the derivatization of 1 with dibromides may lead in principle to a mixture of various geometric isomers, products with various degree of substitution or cross-linked oligomers, the alkylation of 1 with 2,6-bis(bromomethyl)pyridine 2 or 2,6-bis[(tosyloxy)methyl)]pyridine 3 in acetonitrile in the presence of potassium or sodium carbonate was quite straightforward and selective. Thus, derivatives of 6 were isolated after recrystallization in reasonable yields as potassium or sodium cryptates. As judged by the NMR and ESI-MS spectra of the crude reaction mixtures, these reactions were quite selective, and the mixtures were dominated by the cryptates of 6, corresponding to a “diagonal” substitution of macrocycle 1 with two 2,6bismethylenepyridine fragments at the opposite sides of the macrocycle. The ESI-MS spectra of [Na+⊂ R-6]Br, [Na+⊂ S-6]Br, ([K+⊂ R-6]Br) and [K+⊂ R-6]OTs indicate clear signals of molecular ion of the corresponding cationic cryptates (Figures S32 – S37). Similar reactions of 1 with 2 in the presence of lithium or cesium carbonate did not result in isolation of the corresponding cryptates of 6. Nevertheless, a peak at m/z 324.2281 corresponding to ion [Li+⊂ R6+H]2+ of protonated lithium cryptate of 6 can be identified in the ESI-MS spectrum of the reaction mixture, which is very complicated as indicated by NMR spectra. Thus it seems that sodium and potassium cations are the most effective templates for the formation of cryptand 6. The 1H NMR spectrum of [Na+⊂ R-6]Br consists of 13 signals: two triplets and two doublets of two different pyridine rings, four doublets of two different methylene bridges and five signals of the cyclohexane ring (Figure S1). This spectral pattern indicates the effective D2 symmetry of the molecule with the three C2 axes passing across the opposite pyridine rings and the opposite cyclohexane rings. The effective D2 symmetry results from dynamic averaging of the conformations assumed by the “diagonal” pyridine rings. This spectral pattern, together with signal integration, 13C NMR and 2D NMR spectra (Figures S1 – S6) fully supports the structure of these compounds. Apart from the NOE correlation expected for the neighboring fragments of the molecule, an additional correlation between signals b’ and e (Figure S3) is observed, which can only be accounted for by the close contact ca. 2.5 Å observed in the solid state structure (vide infra). The spectrum of the potassium cryptate [K+⊂ R-6]Br is very similar to that of [Na+⊂ R3 ACS Paragon Plus Environment


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6]Br, but the two spectra are sufficiently different to distinguish these compounds. The NMR spectrum of [K+⊂ R-6]OTs is practically identical to that [K+⊂ R-6]Br apart from the additional signals of the tosylate anion. The chiral nature of the cryptates is reflected in their CD spectra (Figure S38).

The unit cell of the enantiomeric sodium cryptates [Na+⊂ R-6]Br⋅2H2O and [Na+⊂ S6]Br⋅0.33MeOH⋅0.5H2O contains three crystallographically independent cations [Na+⊂ 6]+, which are very similar (Figures 1 and S44, S45). The two added pyridine fragments are not perpendicular to the macrocyclic ring of the starting 1, but are sizably inclined towards the original macrocyclic plane. As a result the skeleton of 6 is of approximate C2 symmetry. The nitrogen-sodium distances are similar to those of Lehn’s sodium octaazacryptate or macrocycles bearing pyridine fragments.11 The geometry around the 8-coordinate metal ion is irregular as a consequence of ligand rigidity. The coordination of the two added pyridine rings is unusual as the N-Na bond does not correspond to the direction of nitrogen lone pair (the angle between this bond and the normal to the pyridine mean plane is in the range of 24.7-45.0°). The unit cells of the

potassium

cryptate

crystals,

[K+⊂R-6]Br⋅0.7MeOH⋅0.9H2O

and

[K+⊂ R-

6]Br⋅0.8MeOH⋅0.7H2O, contain four crystallographically independent cations [K+⊂ R-6]+ of similar conformation. The molecular structures of the potassium and sodium cryptates are very similar (Figures S46-S48), with the former being slightly expanded as a result of longer metalnitrogen bonds.

Figure 1. X-ray molecular structure of one of the independent molecules [Na+⊂ R-6]+ of [Na+⊂ R-6]Br·2H2O. The additional two pyridine fragments introduced to the macrocycle 1 are indicated in red. Left – top view of the parent macrocyclic fragment, right – side view of the parent macrocyclic fragment.

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DFT calculations were performed in order to check whether the conformation of cryptand 6 in cryptates [Na+⊂ 6]Br and [K+⊂ 6]Br with the characteristic inclined pyridine rings results from metal binding, and how 6 handles binding of metal ions with increasing size. Dispersioncorrected DFT shows that binding efficiency decreases for the alkali metal series, as reflected in the binding energies (in kcal/mol): -141.8 (Li+); -127.2 (Na+); -87.3 (K+); -59.4 (Rb+); -22.2 (Cs+). The binding energy of H3O+ by 6 is -119.0 kcal/mol. Taking into account the gas-phase nature of the DFT model (no treatment of solvation), one can assume that Rb+ and Cs+ will not be effectively cryptated by 6. A simple semi-quantitative approach – correction of the binding energies by the experimental hydration enthalpies of the metal ions (see Supporting Information) – suggests, however, that the Na+ cation binds to 6 better than Li+, and K+ should also be well cryptated. Structural analysis (see Supporting Information for details and figures) shows that the inclination of the two added “axial” pyridine rings increases from Li+ to Cs+ cryptands, so that the largest ion orients the rings not perpendicularly, but in parallel to the prototypic macrocyclic plane of 1. Of all the ions, K+ is found to provide the best fit to the cavity of 6. The synthesis of [Na+⊂ R-6]Br and [K+⊂ R-6]Br gave the best results when a moderate excess of 2,6-bis(bromomethyl)pyridine 2 was applied. When 0.75 equivalents of 2 were used, the crude reaction mixtures showed additional NMR signals originating from heptaaza semi-cryptand 5. A small amount of the hydrochloride of 5 was isolated via the fractional recrystallization of the reaction mixture from acetonitrile in the presence of hydrochloric acid. Free 5 was obtained in solution after neutralization with base. The structure of this bicyclic semi-cryptand was deduced on the basis of NMR and ESI-MS spectra (Figures S19-22, S31). The formation of 5 is also confirmed by the X-ray crystal structure of its hydrochloride (Figures 2, S50). The conformation of acid chloride salt of 5 is very different to that of 6 observed in cryptates [Na+⊂ 6]Br and [K+⊂ 6]Br (i.e. it does not correspond to a conformation of 6 lacking one of the pyridine tethers). Now the parent macrocycle 1 is sizably bent and the added pyridine fragment is perpendicular to the mean plane of 1.



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Figure 2. Top and side views of X-ray molecular structure of cation R-5 in its hydrochloride derivative, (R-5)Cl4⋅7H2O. The 1H NMR spectrum of a reaction mixture from which [K+⊂ R-6]Br was isolated indicated small amounts of other products (Figure S43). Indeed the addition of perchloric acid to such a crude mixture results in formation of crystals of perchlorate derivative of cryptand 7. The X-ray crystal structure of this compound reveals that 7 is an isomer of 6 and that it adopts a conformation with two pairs of almost parallel pyridine rings (Figures 3, S49). In contrast to cryptand 6, where the opposite “diagonal” amine nitrogen atoms are linked by bis(methylene)pyridine tethers, in the perchlorate salt of protonated cryptand 7 the neighbouring amine nitrogen atoms (i.e. positioned at the same pyridine fragment of parent macrocycle 1) are tethered. Since 7 unlikely resulted from demetalation and rearrangement of [K+⊂ R-6]Br, it originates from the small amount of by-product that has better tendency to crystallize as perchlorate derivative.

Figure 3. Top and side views of X-ray molecular structure of cation R-7 in its perchlorate derivative, (R-7)(ClO4)4⋅0.4H2O.

For comparison, macrocycle 1 was alkylated with benzyl bromide. The obtained derivative 8 exhibits broad signals in 1H NMR spectrum, while the sharp lines are observed for the protonated form, where 2D NMR spectra confirm the structure (see Supporting Information for details). The X-ray crystal structure of the protonated 8 salt with ethyl sulfate has also been determined (Figures 4, S51).


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Figure 4. X-ray molecular structure of doubly protonated molecule of cation R-8 in the crystal (R-8)(EtOSO3)2⋅2MeCN.

Formation of the rigid cryptands 5 and 6 freezes the configuration at the stereogenic amine nitrogen atoms. For a given enantiomer of the macrocycle 1 e.g. R-1, various configurations at the nitrogen atoms lead to diastereomeric forms. Previously, the pure fixed diastereomers (RRRR)(RSRS) and (RRRR)(RRRR) (see Figure 5 for labelling) were observed in the complexed forms of this macrocyle.10

N

R

R

R R

N S

R R N

R

R

1 (RRRR)(RRRR)

N

R N R

R S N

R R N

R

R R N

R R

R N N

N

R

R N

N R

R

R

S N N

1 (RRRR)(RSRS)

N R

R

R

S N N

R

1 (RRRR)(RRSS)

Figure 5. Diastereomeric forms of macrocyle R-1 (R = H) or its derivatives (R = alkyl). The first parenthesis indicate the configuration at cyclohexane carbon atoms, the second one at the amine nitrogen atoms.

As indicated by the X-ray crystal structures, the alkylation pattern of the macrocyclic fragment 1 in cryptand 6 corresponds to a (RRRR)(RRRR) configuration with alternating up and down substituents at the amine nitrogen atoms. This patterns was expected on the basis of the configuration observed for the free macrocycle. In the protonated derivative 8, the substituents are positioned at the same side of the macrocycle, which corresponds to the (RRRR)(RSRS) configuration. This configuration is probably not fixed in a free macrocycle 8, which is reflected in broad 1H NMR signals indicating dynamic rearrangements of various diastereomeric forms in solution. In turn, the cryptand 7, which is isomer of 6, can be regarded as alkylated derivative of the (RRRR)(RRSS) type or (RRRR)(RSRS) type. When aqueous solutions of potassium cryptates [K+⊂ R-6]Br or [K+⊂ R-6]OTs are heated at 353.15 K for 24 h, substantial hydrolysis and demetalation is observed and a mixture of protonated forms of 6 is obtained (Figure S39). In contrast the sodium cryptate [Na+⊂ R-6]Br does not change under analogous conditions, which indicates higher stability. The much higher 7 ACS Paragon Plus Environment


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tendency of 6 to bind Na+ in comparison with K+ is confirmed by the competition experiments monitored by NMR spectroscopy (Figure S40). While [K+⊂ R-6]Br is fully converted to [Na+⊂ R-6]Br by reaction with a Na+ salt, [Na+⊂ R-6]Br does not change at all in the presence of a K+ salt (Scheme 2).

Scheme 2. The competition for 6 between sodium and potassium ions. The outcome of exchange reactions indicate clear preference for Na+ cation.

Scheme 3. The competition reactions between ([Na+⊂ R-6]Br) and cryptand [2.2.1] and between ([K+⊂ R-6]Br) and cryptand [2.2.2]. The uncomplexed R-6 obtained after removal of K+ by cryptand [2.2.2] exists as protonated form.

Similarly, neither [K+⊂ R-6]Br nor [Na+⊂ R-6]Br could be transmetallated with Li+ or Cs+ ions (Figure S40). Although [K+⊂ R-6]Br can be fully demetalated by using strong mineral acids, we were not able to obtain free 6, which seems to have very high basicity. For instance the demetalated forms of 6 obtained in D2O solution give rise to broad signal at ca 9 ppm, which indicate acidic protons (Figure S39). Enhanced basic properties have been observed in the past for other small azacryptands8 as a result of close proximity in space of lone electron pairs, which belong to different nitrogen atoms. In the case of 6 the reason for apparent high basicity is not immediately clear, but it should be mentioned that the binding energy of H3O+ is high (vide 8 ACS Paragon Plus Environment

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supra). Because free 6 was not available, we were not able to determine the metal binding constants by potentiometric methods. The binding properties of 6 are reflected in competition experiments in which the classic cryptands7 [2.2.2] and [2.2.1] were used (Scheme 3). In the reaction of potassium cryptate [K+⊂ R-6]Br with the strong K+ complexation agent [2.2.2]7, gradual demetalation of [K+⊂ R-6]Br and formation of [K+⊂ 2.2.2] was observed (Figure S42). On the contrary, the sodium cryptate [Na+⊂ R-6]Br remained unchanged even when heated with the strong Na+ complexation agent [2.2.1]7 at 358 K for one month. In summary we have demonstrated that the chiral macrocyclic amine 1 can be converted to allaza semicryptand 5 or cryptand 6 by attaching “diagonal” pyridine links. The octaaza cryptand 6, which can be obtained as enantiopure sodium and potassium derivatives, exhibits exceptionally high affinity for sodium cations, higher than that of cryptand [2.2.1]. We plan to further explore formation of chiral metal complexes of 5 and 6 and study them in the context of enantioselective interactions with DNA and chirooptical properties.

EXPERIMENTAL SECTION Measurements. The NMR spectra were taken on Bruker Avance 500 spectrometer. The CD spectra were measured on Jasco J-715 Spectropolarimeter. The electrospray mass spectra were obtained using Bruker microOTOF-Q and apex ultra FT-ICR instruments. The elemental analyses were carried out on a Perkin-Elmer 2400 CHN elemental analyzer. The crystallographic measurements were performed at 100(2)–120(2) K on a κ geometry four-circle diffractometers with graphite-monochromatized Mo Kα or Cu Kα radiation (see Supporting Information for details of data collection and structure refinement). .

DFT Calculations. Structural optimization was performed for 6 and its cryptates with Li+, Na+, K+, Rb+, Cs+ and H3O+ using experimental X-ray coordinates of 8, which is Na+ ⊂ 6, as the starting point. The optimization was followed by harmonic vibrational analysis; no imaginary frequencies were detected. The employed level of theory was RI-DFT approximation with hybrid B3LYP functional, an empirical dispersion correction scheme D3 of Grimme, and a triple-zeta 9 ACS Paragon Plus Environment


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polarized basis set, def2-TZVP (which includes effective core potential replacing core electrons of Rb and Cs).12 The structural calculations were carried out with the Turbomole 6.5 code, while graphical representation of the computational results was prepared with the VMD 1.9.1 program.13

Synthesis Caution: perchlorate salts of organic compounds (8·2HClO4) can be potentially explosive. Macrocycle 1 has been prepared according to the literature procedure.10b

5 – To the acetonitrile solution (100 mL) of chiral hexaaza macrocycle 1 (492.8 mg, 1.134 mmol) was added Na2CO3 (90.1 mg, 0.851 mmol) and acetonitrile solution (300 mL) of 2,6Bis(bromomethyl)pyridine (225.3 mg, 0.851 mmol). The reaction mixture was refluxed for 24 h. Then, the reaction mixture was filtered and filtrate was evaporated to dryness. Crude product was dissolved in chloroform and extracted with water with added Na2CO3 to adjust the pH to 13. The organic fraction was dried over Na2CO3, filtered and evaporated to dryness. Crude mixture containing semi-cryptand 5 was obtained (429.5 mg). Part of this product was purified by crystallization from acetonitrile/conc. HCl solution to yield small amount (ca. 3 mg) of crystalline hydrochloride (R-5)⋅4HCl⋅7H2O, which was collected manually. The pure free compound 5 was obtained as a solution for NMR measurements by the neutralization of ca. 2 mg of hydrochloride derivative with K2CO3 in 1 mL of D2O and extraction with CDCl3. The NMR spectrum of thus purified product was identical to that the main component of the crude product. 1H NMR (500 MHz, CDCl3): δ 7.51 (t, J = 7.6 Hz, 1H), 7.37 (t, J = 7.6 Hz, 2H), 6.98 (d, J = 7.6 Hz, 2H), 6.97 (d, J = 7.5 Hz, 2H), 6.73 (d, J = 7.7 Hz, 2H), 4.15 (d, J = 14.4 Hz, 2H), 3.96 (s, 4H), 3.86 (d, J = 14.4 Hz, 2H), 3.50 (d, J = 14.6 Hz, 2H), 2.73 (m), 2.36 (d, J = 14.5 Hz, 2H), 2.02 (m), 1.89 (m), 1.86 (m), 1.77 (m), 1.65 (m), 1.32 (m), 1.13 (m), 0.94 (m). 13C NMR (500 MHz, CDCl3): δ 160.1, 159.8, 159.0, 136.4, 135.4, 122.4, 119.9, 119.3, 66.1, 62.3, 58.3, 54.6, 50.5, 32.1, 25.9, 24.7, 23.2. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C33H44N7 538.3653; found 538.3663.

[Na+⊂ R-6]Br – To the acetonitrile solution (100 mL) of chiral hexaaza macrocycle 1 (503.4 mg, 1.16 mmol) was added Na2CO3 (245.6 mg, 2.320 mmol) and acetonitrile solution (30 mL) of 2,6Bis(bromomethyl)pyridine (613.6 mg, 2.320 mmol). The reaction mixture was refluxed for 24 h. 10 ACS Paragon Plus Environment

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Then, the reaction mixture was filtered and the filtrate was evaporated to dryness. The crude product was dissolved in chloroform and extracted with water with added Na2CO3 to adjust the pH to 13. The organic fraction was dried over Na2CO3, filtered and evaporated to dryness. Crude product was dissolved in acetonitrile and dropwise addition of an diethyl ether induced precipitation of product, which was filtered off, washed with diethyl ether and dried to give [Na+⊂ R-6]Br (585.3 mg, 52.4%). Anal. Calc. (found) for C40H50N8ONaBr: C, 62.9 (63.07); H, 6.49 (6.61); N, 14.59 (14.71). 1H NMR (500 MHz, CDCl3): δ 7.49 (t, J = 7.7 Hz, 2H), 7.18 (t, J = 7.7 Hz, 2H), 6.98 (d, J = 7.7 Hz, 4H), 6.56 (d, J = 7.7, 4H), 3.78 (d, J = 14.8 Hz, 4H), 3.67 (d, J = 8.6 Hz, 4H), 3.64 (d, J = 9.8 Hz, 4H), 3.48 (d, J = 13.6 Hz, 4H), 2.89 (t, J = 4.9 Hz, 4H), 2.16 (m, 4H), 1.86 (m, 4H), 1.55 (m, 4H), 1.19 (m, 4H).

13

C NMR (500 MHz, CDCl3): δ 159.7, 157.7,

137.5, 137.4, 122.0, 121.6, 62.7, 60.5, 55.8, 25.6, 24.3. CD [CH3CN, λmax/nm, (∆ε/M-1cm-1)]: 223.0 (11.45), 249.0 (-10.54), 274.6 (31.96). HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C40H48N8Na 663.3894; found 663.3899. [Na+⊂ S-6]Br was obtained in the same way as the all-R enantiomer described above with the use all-S enantiomer of chiral hexaaza macrocycle 1 (98.3 mg, 0.226 mmol), Na2CO3 (47.9 mg, 0.452 mmol) and 2,6-Bis(bromomethyl)pyridine (119.9 mg, 0.452 mmol). Pure product [Na+⊂ S6]Br was obtained (188.0 mg, 47.3%). Anal. Calc. (found) for C40H52N8O2NaBr: C, 61.80 (61.69); H, 6.33 (6.60); N, 14.11 (14.39). 1H NMR (500 MHz, CDCl3): δ 7.49 (t, J = 7.7 Hz, 2H), 7.18 (t, J = 7.7 Hz, 2H), 6.98 (d, J = 7.7 Hz, 4H), 6.56 (d, J = 7.7, 4H), 3.78 (d, J = 14.8 Hz, 4H), 3.67 (d, J = 8.6 Hz, 4H), 3.64 (d, J = 9.8 Hz, 4H), 3.48 (d, J = 13.6 Hz, 4H), 2.89 (t, J = 4.9 Hz, 4H), 2.16 (m, 4H), 1.86 (m, 4H), 1.55 (m, 4H), 1.19 (m, 4H). 13C NMR (500 MHz, CDCl3): δ 159.7, 157.7, 137.5, 137.4, 122.0, 121.6, 62.7, 60.5, 55.8, 25.6, 24.3. CD [CH3CN, λmax/nm, (∆ε/M-1cm-1)]: 223.0 (-8.82), 249.0 (8.60), 274.6 (-23.54). HRMS (ESI-TOF) m/z: [M + Na]+ calcd for C40H48N8Na 663.3894; found 663.3904. [K+⊂ R-6]Br was obtained in the same way as [Na+⊂ R-6]Br with the use K2CO3 instead of Na2CO3 to give [K+⊂ R-6]Br (654.5 mg, 55.9%). Anal. Calc. (found) for C41H54N8O2NaBr: C, 60.56 (60.79); H, 6.76 (6.72); N, 13.86 (13.84). 1H NMR (500 MHz, CDCl3): δ 7.52 (t, J = 7.7 Hz, 2H), 7.16 (t, J = 7.7 Hz, 2H), 7.03 (d, J = 7.7 Hz, 4H), 6.58 (d, J = 7.7 Hz, 4H), 3.82 (d, J = 13.2 Hz, 4H), 3.77 (d, J = 15.2 Hz, 4H), 3.69 (d, J = 15.1 Hz, 4H), 3.59 (d, J = 13.2 Hz, 4H), 2.94 11 ACS Paragon Plus Environment


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(t, J = 4.9 Hz, 4H), 2.18 (m,4H), 1.85 (m, 4H), 1.53 (m, 4H), 1.19 (m, 4H). 13C NMR (500 MHz, CDCl3): δ 157.8, 157.5, 137.7, 137.0, 122.8, 122.0, 63.6, 61.6, 56.2, 25.5, 24.3. CD [CH3CN, λmax/nm, (∆ε/M-1cm-1)]: 220.9 (13.78), 247.5 (-2.67), 273.4 (16.89). HRMS (ESI-TOF) m/z: [M + K]+ calcd for C40H48N8K 679.3634; found 679.3640. [K+⊂ R-6]OTs was obtained in the same way as [Na+⊂ R-6]Br with the use 2,6bis[(tosyloxy)methyl)]pyridine instead of 2,6-bis(bromomethyl)pyridine. Anal. Calc. (found) for C46H57N8O5SK: C, 63.01 (63.27); H, 6.30 (6.58); N, 12.51 (12.83). 1H NMR (500 MHz, CDCl3): δ 7.78 (d, J = 8.15 Hz, 2H), 7.51 (t, J = 7.7 Hz, 2H), 7.14 (t, J = 7.7 Hz, 2H), 7.02 (d, J = 7.7 Hz, 6H), 6.57 (d, J = 7.7 Hz, 4H), 3.81 (d, J = 13.3 Hz, 4H), 3.76 (d, J = 15.1 Hz, 4H), 3.68 (d, J = 15.0 Hz, 4H), 3.58 (d, J = 13.2 Hz, 4H), 2.93 (t, J = 5.0 Hz, 4H), 2.23 (s, 3H), 2.17 (m, 4H), 1.84 (m, 4H), 1.52 (m, 4H), 1.18 (m, 4H). 13C NMR (500 MHz, CDCl3): δ 157.8, 157.5, 137.8, 137.0, 128.4, 126.5, 122.9, 122.0, 63.6, 61.6, 56.2, 25.5, 24.3, 21.5. CD [CH3CN, λmax/nm, (∆ε/M-1cm1

)]: 218.4 (12.24), 247.5 (-3.13), 273.4 (16.89). HRMS (ESI-TOF) m/z: [M + K]+ calcd for

C40H48N8K 679.3634; found 679.3645. 8 – To the acetonitrile solution (70 mL) of chiral hexaaza macrocycle 1 (614.4 mg, 1.414 mmol) was added K2CO3 (820.8 mg, 5.939 mmol), the reaction mixture was brought to reflux and the solution of 706 µL (5.959 mmol) of benzyl bromide in 10 mL acetonitrile was added dropwise. The reaction mixture was refluxed for 24 h. Then, the reaction mixture was filtered and filtrate was evaporated to dryness. The crude product was dissolved in chloroform and extracted with water with added K2CO3 to adjust the pH to 13. The organic fraction was dried over K2CO3, filtered, washed with acetonitrile (2 x 5 mL) and evaporated to dryness to give 8 (609.2 mg, 54.2%). Anal. Calc. (found) for C54H64N6O: C, 79.61 (79.76); H, 7.89 (7.93); N, 10.30 (10.34). 1

H NMR (500 MHz, CDCl3): δ 7.62 – 6.43 (m), 3.93 – 3.44 (m), 2.59 (m), 2.14 (m), 1.72 – 1.00

(m). HRMS (ESI-TOF) m/z: [M + H]+ calcd for C54H63N6 795.5109; found 795.5096. 8·2HClO4 – To the acetonitrile solution of 8 (40.6 mg, 0.051 mmol) was added the solution of 0.102 mmol of 2.55 M perchloric acid in acetonitrile. The formed precipitate was filtered off and dried under vacuum to give (41.6 mg, 81.6%). 1H NMR (500 MHz, CDCl3): δ 8.90 (s, 2H), 8.01 (t, J = 7.7 Hz, 2H), 7.96 (d, J = 7.6 Hz, 2H), 7.46 (d, J = 7.8 Hz, 2H), 7.46 (t, J = 8.3 Hz, 2H), 12 ACS Paragon Plus Environment

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7.18 (t, J = 7.8 Hz, 4H), 7.13 (t, J = 7.3 Hz, 2H), 7.06 (t, J = 7.5 Hz, 4H), 6.88 (d, J = 7.4 Hz, 2H), 6.80 (d, J = 7.6 Hz, 2H), 4.74 (m, 2H), 3.73 (d, J = 9.2 Hz, 2H), 3.72 (d, J = 12.6 Hz, 2H), 3.62 (d, J = 12.5 Hz, 2H), 3.44 (d, J = 12.2 Hz, 2H), 3.40 (d, J = 13.1 Hz, 2H), 3.32 (d, J = 13.3 Hz, 2H), 3.29 (d, J = 13.1 Hz, 2H), 2.81 (t, J = 10.7 Hz, 2H), 2.65 (m, 2H), 2.40 (m, 2H), 2.15 (m, 2H), 1.95 (m, 2H), 1.80 (m, 2H), 1.48 (m, 2H), 1.18 (m, 2H), 1.05 (m, 2H), 0.88 (m, 2H). 13C NMR (500 MHz, CDCl3): δ 160.0, 150.8, 139.4, 135.1, 131.2, 130.2, 130.1, 129.9, 129.1, 128.9, 127.5, 127.3, 125.7, 62.1, 57.9, 55.4, 54.7, 53.9, 52.6, 24.7, 24.5, 24.2. HRMS (ESI-TOF) m/z: [M + H]+ calcd for C54H63N6 795.5109; found 795.5110.

8·2C2H5OSO3H·2CH3CN The solution of ethylsufate sodium salt (13.21 mg, 0.089 mmol) in 1 mL of water was combined with solution of 8 (28.10 mg, 0.035 mmol) in 1.5 mL of chloroform and 7.5 µL of concentrated HCl. The mixture was shaken vigorously and stirred for 0.5 h; the chloroform phase was separated and evaporated to dryness. The residue was dissolved in acetonitrile and the product was precipitated by diethyl ether vapor diffusion, separated and dried in air. Yield 25.7 mg (69.4%). 1H NMR (500 MHz, CDCl3): δ 8.58 (s, 2H), 8.29 (d, J = 7.8 Hz, 2H), 8.00 (t, J = 7.6 Hz, 2H), 7.40 (m, 4H), 7.18 (t, J = 7.6 Hz, 4H), 7.11 (t, J = 7.4 Hz, 2H), 7.03 (t, J = 7.5 Hz, 4H), 6.90 (d, J = 7.7 Hz, 4H), 6.84 (d, J = 7.6 Hz, 4H), 5.24 (m, 2H), 4.23 (q, J = 7.1 Hz, 4H), 4.12 (m, 2H), 3.69 (d, J = 12.5 Hz, 2H), 3.58 (d, J = 12.5 Hz, 2H), 3.38 (d, J = 13.3 Hz, 2H), 3.32 (m, 4H), 3.21 (d, J = 12.5 Hz, 2H), 2.84 (m, 4H), 2.28 (m, 2H), 2.17 (m, 2H), 2.00 (m, 2H), 1.78 (m, 2H), 1.54 (m, 2H), 1.39 (t, J = 7.1 Hz, 6H), 1.19 (m, 4H), 0.87 (m, 6H).

ASSOCIATED CONTENT Supporting Information NMR and CD spectra, crystallographic data (including thermal ellipsoid plots), detailed discussion of DFT calculations, Cartesian coordinates of DFT models, as well as X-ray crystallographic information in CIF format. This material is available free of charge via the Internet at http://pubs.acs.org. AUTHOR INFORMATION Corresponding Author 13 ACS Paragon Plus Environment


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*[email protected] ACKNOWLEDGMENTS This research was supported by NCN (Narodowe Centrum Nauki, Poland) grant 2013/11/N/ST5/01373. REFERENCES (1) (a) Lehn, J. M. Cryptates – the Chemistry of Macropolycyclic Inclusion Complexes. Acc. Chem. Res. 1978, 11, 49-57. (b) Dietrich, B.; Lehn, J. M.; Sauvage, J. P. Cryptates. Tetrahedron Lett. 1969, 34, 2889-2892. (2) Zhang, M. M.; Yan, X. Z.; Huang, F. H.; Niu, Z. B.; Gibson, H. W. Stimuli-Responsive Host-Guest Systems Based on the Recognition of Cryptands by Organic Guests Acc. Chem. Res. 2014, 47, 1995-2005. (3) (a) Alpha, B.; Balzani, V.; Lehn, J. M.; Perathoner, S.; Sabbatini, N. Luminescence Probes: The Eu3+- and Tb3+- Cryptates of Polypyridine Macrobicyclic Ligands. Angew. Chem. Int. Ed. 1987, 26, 1266-1267. (b) Bkouchewaksman, I.; Guilhem, J.; Pascard, C.; Alpha, B.; Deschenaux, R.; Lehn, J. M. Crystal Structures of the Lanthanum(III), Europium(III), and Terbium(III) Cryptates of Tris(bipyridine) Macrobicyclic Ligands. Helv. Chim. Acta 1991, 74, 1163-1170. (c) Stauber, J. M.; Bloch, E. D.; Vogiatzis, K. D.; Zheng, S. L.; Hadt, R. G.; Hayes, D.; Chen, L. X.; Gagiardi, L.; Nocera, D. G.; Cummins, C. C. Pushing Single-Oxygen-Atom-Bridged Bimetallic Systems to the Right: A Cryptand-Encapsulated Co-O-Co Unit. J. Am. Chem. Soc. 2015, 137, 15354-15357. (d) Zahim, S.; Wickramasinghe, L. A.; Evano, G.; Jabin, I.; Schrock, R. R.; Muller, P. Calix[6]azacryptand Ligand with a Sterically Protected Tren-Based Coordination Site for Metal Ions. Org. Lett. 2016, 18, 1570-1573. (e) Jin, G. X.; Bailey, M. D.; Allen, M. J. Unique EuII Coordination Environments with a Janus Cryptand. Inorg. Chem. 2016, 55, 9085-9090. (4) (a) Amendola, V.; Bergamaschi, G.; Boiocchi, M.; Alberto, R.; Braband, H. Fluorescent Sensing of 99Tc Pertechnetate in Water. Chem. Sci. 2014, 5, 1820-1826. (b) Mateus, P.; Delgado, R.; Andre, V.; Duarte, M. T. Sulfate Recognition by a Hexaaza Cryptand Receptor. Org.Biomol. Chem. 2015, 13, 834-842. (c) Mateus, P.; Delgado, R.; Brandao, P.; Felix, V. Polyaza Cryptand Receptor Selective for Dihydrogen Phosphate. J. Org. Chem. 2009, 74, 8638-8646. (d) Saeed, M. A.; Fronczek, F. R.; Hossain, M. A. Encapsulated Chloride Coordinating with Two in-in Protons of Bridgehead Amines in an Octaprotonated Azacryptand. Chem. Commun. 2009, 6409-6411. (e) 14 ACS Paragon Plus Environment

Page 15 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Saeed, M. A.; Fronczek, F. R.; Huang, M. J.; Hossain, M. A. Unusual Bridging of Three Nitrates with two Bridgehead Protons in an Octaprotonated Azacryptand. Chem. Commun. 2010, 46, 404406. (f). Kang, S. O.; Llinares, J. M.; Day, V. W.; Bowman-James, K. Cryptand-like Anion Receptors. Chem. Soc. Rev. 2010, 39, 3980-4003. (g) Mateus, P.; Bernier, N.; Delgado, R. Recognition of Anions by Polyammonium Macrocyclic and Cryptand Receptors: Influence of the Dimensionality on the Binding Behavior. Coord. Chem. Rev. 2010, 254, 1726-1747. (5) (a) Echegoyen, L.; Decian, A.; Fischer, J.; Lehn, J. M. Cryptatium: A Species of Expandede Atom/Radical Ion Pair Type from Electroreductive Crystallization of the Macrobicyclic Sodium Tris(Bipyridine) Cryptate. Angew. Chem. Int. Ed. 1991, 30, 838-840. (b) Redko, M. Y.; Huang, R. H.; Jackson, J. E.; Harrison, J. F.; Dye, J. L. Barium Azacryptand Sodide, the First Alkalide with an Alkaline Earth Cation, Also Contains a Novel Dimer, (Na2)2-. J. Am. Chem. Soc. 2003, 125, 2259-2263. (c) Redko, M. Y.; Jackson, J. E.; Huang, R. H.; Dye, J. L. Design and Synthesis of a Thermally Stable Organic Electride. J. Am. Chem. Soc. 2005, 127, 12416-12422. (6) (a) Brachvogel, R. C.; Hampel, F.; von Delius, M. Self-assebly of Dynamic Orthoester Cryptates. Nat. Commun. 2015, 6, 7129. (b) He, H. R.; Mortellaro, M. A.; Leiner, M. J. P.; Fraatz, R. J. A Fluorescent Sensor with High Selectivity and Sensitivity for Potassium in Water. J. Am. Chem. Soc. 2003, 125, 1468-1469. (c) Kong, X. X.; Su, F. Y.; Zhang, L. Q.; Yaron, J.; Lee, F.; Shi, Z. W.; Tian, Y. Q.; Meldrum, D. R. A Highly Selective Mitochondria-Targeting Fluorescent K+ Sensor. Angew. Chem. Int. Ed 2015, 54, 12053-12057. (d) Sui, B. L.; Yue, X. L.; Tichy, M. G.; Liu, T. H.; Belfield, K. D. Improved Synthesis of the Triazaxryptand (TAC) and its Application in the Construction of a Fluorescent TAC-BODIPY Conjugate for K+ Sensing in Live Cells. Eur. J. Org. Chem. 2015, 1189-1192. (e) Zhou, X. F.; Su, F. Y.; Tian, Y. Q.; Youngbull, C.; Johnson, R. H.; Meldrum, D. R. A New Highly Selective Fluorescent K+ Sensor. J. Am. Chem. Soc.2011, 133, 18530-18533. (7) (a) Lehn, J. M.; Sauvage, J. P. [2]-Cryptates. Stability and Selectivity of Alkali and Alkaline-earth Macrobicyclic Complexes. J. Am. Chem. Soc. 1975, 97, 6700-6707. (b) Izatt, R. M., Pawlak, K., Bradshaw, J. S.; Bruening, R. L. Thermodynamic and Kinetic Data for Macrocycle Interactions with Cations and Anions. Chem. Rev. 1991, 91, 1721-2085. (8) (a) Alibrandi, G.; Arena, C. G.; Lando, G.; Lo Vecchio, C.; Parisi, M. F. {[1.1.1]Cryptand/Imidazole}: A Prototype Composite Kinetic Molecular Device for Automatic NMR Variable pH Reaction Monitoring. Chem. Eur. J. 2011, 17, 1419-1422. (b) Alibrandi, G.; 15 ACS Paragon Plus Environment


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Lister, D. G.; Lo Vecchio, C.; Maeder, M. [1.1.1]Cryptand: Directions for its Use as a VariablepH Kinetic Molecular Device. New J. Chem. 2014, 38, 561-567. (c) Chambron, J. C.; Meyer, M. The Ins and Outs of Proton Complexation. Chem. Soc. Rev. 2009, 38, 1663-1673. (d) Morehouse, P.; Hossain, M. A.; Llinares, J. M.; Powell, D.; Bowman-James, K. A Ditopic Azacryptate Proton Cage. Inorg. Chem. 2003, 42, 8131-8133. (9) (a) Bharadwaj, P. K. Metal Ion Binding by Laterally Non-symmetric Macrobicyclic Oxa-aza Cryptands. Dalton Trans. 2017, 46, 5742-5775. (b) Bonnot, C.; Chambron, J. C.; Espinosa, E.; Bernauer, K.; Scholten, U.; Graff, R. The Proton Complex of a Diaza-macropentacycle: Structure, Slow Formation, and Chirality Induction by Ion Pairing with the Optically Active 1,1’Binaphthyl-2,2’-diyl Phosphate Anion. J. Org. Chem. 2008, 73, 7871-7881. (c) De, D.; Bhattacharyya, A.; Bharadwaj, P. K. Enantioselective Aldol Reactions in Water by a ProlineDerived Cryptand and Fixation of CO2 by Its Exocyclic Co(II) Complex. Inorg. Chem. 2017, 56, 11443-11449. (d) Garcia, C.; Pointud, Y.; Jeminet, G.; Dugat, D. Novel Cryptand Analogs Incorporating a Chiral Spiran Moiety. Tetrahedron Lett. 1999, 40, 4993-4996. (e) Guden-Silber, T.; Doffek, C.; Platas-Iglesias, C.; Seitz, M. The First Enantiopure Lanthanoid Cryptate. Dalton Trans. 2014, 43, 4238-4241. (f) Kreidt, E.; Dee, C.; Seitz, M. Chiral Resolution of Lanthanoid Cryptates with Extreme Configurational Stability. Inorg. Chem. 2017, 56, 8752-8754. (g) Macgillivray, L. R.; Atwood, J. L. Proton-Induced Chirality: Proton Complexation in the Chiral Cryptand 222-2H+ Dication Isolated from a Liquid Clathrate Medium. J. Org. Chem. 1995, 60, 4972-4973. (h) Shyshov, O.; Brachvogel, R. C.; Bachmann, T.; Srikantharajah, R.; Segets, D.; Hampel, F.; Puchta, R.; von Delius, M. Adaptive Behavior of Dynamic Orthoester Cryptands. Angew. Chem. Int. Ed. 2017, 56, 776-781. (10) (a) Gerus, A.; Ślepokura, K.; Lisowski, J. Anion and Solvent Induced Chirality Inversion in Macrocyclic Lanthanide Complexes. Inorg. Chem., 2013, 52, 12450-12460. (b) Gregoliński, J.; Lisowski, J.; Ślepokura, K. Lanthanide Complexes of the Chiral Hexaaza Macrocycle and its Meso-type Isomer: Solvent-controlled Helicity Inversion. Inorg. Chem., 2007, 46, 7923-7934. (11) (a) Echegoyen, L.; DeCian, A.; Fischer, J.; Lehn, J.-M. Cryptatium: A Species of Expanded Atom/Radical Ion Pair Type from Electroreductive Crystallization of the Macrobicyclic Sodium Tris(Bipyridine) Cryptate. Angew.Chem.,Int.Ed. 1991, 30, 838-840. (b) Caron, A.; Guilhem, J.; Riche, C.; Pascard, C.; Alpha, B.; Lehn, J.-M.; Rodriguez-Ubis, J.-C. Photoactive Cryptands Helv. Chim. Acta 1985, 68, 1577, (c) McKee, V.; Dorrity, M. R. J.; Malone, J. F.; Marrs, D.; 16 ACS Paragon Plus Environment

Page 17 of 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Nelson, J. Novel Group 1 Cation Cryptates: X-ray and

23

Na NMR Studies. Chem. Commun.

1992, 383-386. (d) Misaki, H.; Miyake, H.; Shinoda, S.; Tsukube, H. Asymmetric Twisting and Chirality Probing Propertie of Quadruple-Stranded Helicates: Coordination Versatility and Chirality Response of Na+, Ca2+, and La3+ Complexes with Octadentate Ligand. Inorg. Chem. 2009, 48, 11921-11928. (e) Ito, H.; Tsukube, H.; Shinoda, S. Chiralilty Transfer in PropellerShaped CyclenCalcium(II) Complexes: Metal Coordinating Ion-Pairing Anion Procedures. Chem. Eur. J. 2013, 19, 3330-3339. (12) (a) Eichkorn, K.; Treutler, O.; Öhm, H.; Häser, M.; Ahlrichs, R. Auxiliary Basis Sets to Approximate Coulomb Potentials. Chem. Phys. Lett. 1995, 242, 652-660; (b) Eichkorn, K.; Weigend, F.; Treutler, O.; Ahlrichs, R. Auxiliary Basis Sets for Main Row Atoms and Transition Metals and Their Use to Approximate Coulomb Potentials. Theor. Chem. Acc. 1997, 97, 119124; (c) Becke, A. D. Density-functional Thermochemistry. III. The Role of Exact Exchange. J. Chem. Phys. 1993, 98, 5648-5652; (d) Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. A Consistent and Accurate ab Initio Parametrization of Density Functional Dispersion Correction (DFT-D) fort he 94 Elements H-Pu. J. Chem. Phys. 2010, 132, 154104. (13) (a) TURBOMOLE V6.5 2013, a development of University of Karlsruhe and Forschungszentrum Karlsruhe GmbH, 1989-2007, TURBOMOLE GmbH, since 2007; available from http://www.turbomole.com; (b) Humphrey, W.; Dalke, A.; Schulten, K. VMD - Visual Molecular Dynamics. J. Mol. Graphics. 1996, 14, 33-38.


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