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Tetra- and hexanuclear nitrate, chloride and sulphate Ni(ii) and Cu(ii) complexes have been synthesized from metal salts and 6 + 6 macrocycle. The ligand conformation in the complexes depends on the number of metal cations bound with the macrocycle.

All 4 + 4 diastereomeric amine macrocycles derived from trans-1,2-diaminocyclopentane and 2,6-difromylpyridine have been synthesized. Chiral compounds exhibit chiral resolution towards 10-camphorsulfonic and tartaric acids.

The condensation reaction of 2,6-diformylpyridine with an equimolar mixture of opposite enantiomers of trans-1,2-diaminocyclopentane and trans-1,2-diaminocyclohexane using a dynamic combinatorial chemistry approach has been examined. In nonmetal-templated reactions, depending on reaction conditions, mixed 2 + 1 + 1 macrocyclic imine or bigger mixed 4 + 2 + 2 imine macrocycle are formed selectively. The 2 + 1 + 1 imine used as a precursor in the templated by CdII ions produces a library of enlarged chiral mixed imines coordinated with metal cations among which the hexanuclear CdII complex of 6 + 3 + 3 imine was isolated and characterized. All macrocyclic imine compounds have been reduced to the corresponding macrocyclic amines, which have been further transformed into their hydrochlorides. Each macrocyclic compound has been obtained as two enantiomers. For imine macrocycles and for the hydrochloride derivatives of macrocyclic amines, their X-ray crystal structures have been determined. In particular, the crystals of protonated 4 + 2 + 2 macrocyclic amine, which contains two types of diastereomeric cations differing in terms of inverted twists of pyridine moieties, and hexanuclear CdII complex of 6 + 3 + 3 imine, which gives a deeper insight into the expansion reaction, have been investigated. A heterochiral self-sorting of 2 + 2 and 2 + 1 + 1 macrocyclic imines has been confirmed by a competition reaction of 2,6-diformylpyridine, racemic trans-1,2-diaminocyclopentane, and racemic trans-1,2-diaminocyclohexane and theoretical calculations.

While the non-templated reaction of racemic trans-1,2-diaminocyclohexane with 2,6-diformylpyridine leads to a mixture of 2 + 2 and 4 + 4 macrocyclic imines, the reaction of the isolated 2 + 2 macrocycle with cadmium(II) chloride results in the fusion of three smaller macrocyclic units into a large 6 + 6 macrocycle. The X-ray molecular structures of the hexanuclear cadmium complex of this macrocycle as well as the derived 6 + 6 protonated amine reveal multiply folded macrocycles that adopt container-type conformations.

The enantiopure mononuclear coordination compounds [Ln(L1)]Cl3·nH2O (Ln = Y(III), Nd(III), Sm(III), Eu(III), Tb(III), Yb(III)) of the chiral macrocyclic (2+2) imine L1 (L1RRRR and L1SSSS), derived from (1R,2R) and (1S,2S)-1,2-diaminocyclopentane (DACP) and 2,6-diformylpyridine (DFP), have been synthesized in the templated condensation of the precursors in the presence of the appropriate metal salts. From the racemic trans-DACP and DFP in the templated condensation, a series of racemic mononuclear coordination compounds [Ln(L1rac)]Cl3·nH2O (Ln = Y(III), Nd(III), Sm(III), Eu(III), Tb(III), Yb(III)) have been obtained. In the absence of metal salt, the condensation of the achiral precursors leads to a meso type Schiff base L2, which in the presence of lanthanide(III) salts produced the mononuclear coordination compounds [Ln(L2)]Cl3·nH2O (Ln = Y(III), Nd(III), Sm(III), Eu(III), Tb(III)). The mononuclear coordination compounds with the L1 and L2 ligands have been characterised by NMR spectroscopy, mass spectrometry, elemental analyses and/or circular dichroism (CD). 1H NMR signals of CDCl3/CD3OD solutions of the Y(III), Nd(III), Sm(III) and Eu(III) coordination compounds have been assigned on the basis of their COSY and HMQC spectra, and for the remaining lanthanide coordination compounds (Tb(III) and Yb(III)) the signals were tentatively assigned on the basis of linewidths analyses. The properties and stability of the lanthanide(III) and yttrium(II) coordination compounds of the racemic macrocycle L1rac have been compared with those of the isomeric meso type macrocycle L2 in organic solvents and water. Axial ligand exchange for several coordination compounds was investigated by 1H NMR titration experiments in organic solvents. The X-ray crystal structures of the representative mononuclear coordination compounds [Nd(L1RRRR)Cl(H2O)2]Cl2·0.5MeOH·H2O, [Nd(L1rac)Cl(H2O)2]Cl2·1.6MeOH·0.2H2O, [Y(L1rac)Cl(H2O)2]Cl2·3.5H2O, [Y(L1rac)Cl(H2O)2][Y(L1rac)(H2O)3]Cl5·6.8H2O and [Nd(L2)Cl2(H2O)]Cl with the diastereomeric ligands L1 and L2 have been determined.

A large macrocyclic ligand containing six pyridine fragments and six diaminocyclopentane fragments is able to form hexanuclear Zn(II) and Ni(II) complexes as well as a trinuclear Zn(II) complex. X-ray crystal structures of these complexes indicate quite different ligand conformations. In the hexanuclear Zn(II) derivative with chloride counteranions metal ions have a distorted-trigonal-bipyramidal geometry and occupy loop sections formed by the highly folded macrocycle, which adopts a globular shape. In the hexanuclear Ni(II) derivative with nitrate counteranions metal ions exhibit a distorted-octahedral geometry and the ligand conformation is much more open, while in the trinuclear Zn(II) complex the macrocycle wraps around the octahedral metal ions. The last highly entangled conformation of the trinuclear complex is also present in solution, as confirmed by the NOESY spectra. The NMR data indicate that the hexanuclear Zn(II) complex partially dissociates in water solutions to form the trinuclear complex, while the

Octulene, the higher homologue of kekulene and septulene, was synthesized using the fold-in method. This new hydrocarbon macrocycle contains a large 24-membered inner circuit, which is peripherally fused to 24 benzene rings. Such an arrangement produces considerable hyperbolic distortion of the π-conjugated surface. The consequences of distortion in octulene were explored using photophysical methods, which revealed a reduced electronic band gap and greater flexibility of the π system. Octulene contains a functional cavity with a diameter larger than 5.5 A that is capable of efficiently binding the chloride anion in a nonpolar solvent (Ka= 2.2(4)×104 m−1, 1 % dichloromethane (DCM) in benzene). The octulene–chloride interaction is stabilized by eight weak C(sp2)H⋅⋅⋅Cl bonds, providing the first example of a hydrocarbon-based anion receptor.

Monomeric nitrate coordination compounds [Ln(L1)](NO3)3·nH2O (Ln = Y(III), Tm(III), Yb(III) and Lu(III)); n = 0, 0.75 or 3) 1 of the chiral macrocyclic (2 + 2) imine L1 (L1RRRR, L1SSSS and/or L1rac), derived from enantiomerically pure or racemic trans-1,2-diaminocyclopentane (DACP) and 2,6-diformylpyridine (DFP), have been synthesized in the templated condensation of precursors in the presence of appropriate metal salts. From these monomers their homochiral μ-hydroxodimers [Ln2(L1)2(μ-OH)2](NO3)4·nH2O (Ln = Y(III), Tm(III), Yb(III) and Lu(III)); n = 4, 5 or 7) have been obtained and isolated by addition of NaOH to the respective monomeric form of coordination compound solution. All synthesized coordination compounds have been characterized by NMR spectroscopy, mass spectrometry, elemental analyses and/or circular dichroism (CD). 1H NMR signals of CDCl3/CD3OD solutions of the diamagnetic Y(III) and Lu(III) monomers have been assigned on the basis of their COSY and HMQC spectra, and for the remaining paramagnetic lanthanide coordination compounds (Tm(III) and Yb(III)) the signals were tentatively assigned on the basis of linewidths analyses. 1H NMR signals of D2O solutions of diamagnetic Y(III) and Lu(III) representatives of dimeric species have been established taking into account their COSY, HMQC, HMBC and NOESY spectra. The NOESY spectra confirm that the structure of the dimmers observed in solids is also maintained in a solution. The axial ligand exchange in all monomeric coordination compounds was investigated by 1H NMR titration experiments with acetate and chloride anions in organic solvents as well as with hydroxide anion in D2O. The formation of homochiral heterobimetallic μ-hydroxodimers [Ln’Ln”(L1)2(μ-OH)2](NO3)4 was investigated in a solution by mixing the solutions of two different [Ln’2(L1)2(μ-OH)2](NO3)4·nH2O and [Ln”2(L1)2(μ-OH)2](NO3)4·nH2O homochiral homobimetallic precursors. This experiment proves the chiral recognition between two macrocyclic units of the same chirality in a solution. The μ-hydroxodimers may convert with time to the corresponding peroxo-dimers of the general formula [Ln2(L1)2(μ-η2: η2-O2)](NO3)4. The X-ray crystal structures of the representative monomeric and dimeric coordination compounds [Yb(L1RRRR)(NO3)2]NO3, [Yb2(L1SSSS)2(OH)2(H2O)2](NO3)4·2MeOH·2H2O, [Yb2(L1RRRR)2(OH)2(H2O)2][Yb2(L1SSSS)2(OH)2(H2O)2](NO3)8·1.5MeOH·5H2O and [Y2(L1SSSS)2(O2)(NO3)2](NO3)2·2MeOH with enantiomerically pure or racemic ligand L1 have been determined. The structure of [Yb2(L1RRRR)2(OH)2(H2O)2][Yb2(L1SSSS)2(OH)2(H2O)2] (NO3)8·1.5MeOH·5H2O crystal confirms chiral recognition of macrocyclic units of the same chirality in solids.

[4]Chrysaorene, a fully conjugated carbocyclic coronoid, is shown to be a low-bandgap π-conjugated system with a distinct open-shell character. The system shows good chemical stability and can be oxidized to well-defined radical cation and dication states. The cavity of [4]chrysaorene acts as an anion receptor toward halide ions with a particular selectivity toward iodides (Ka = 207 ± 6 M–1). The interplay between anion binding and redox chemistry is demonstrated using a 1H NMR analysis in solution. In particular, a well-resolved, paramagnetically shifted spectrum of the [4]chrysaorene radical cation is observed, providing evidence for the inner binding of the iodide. The radical cation–iodide adduct can be generated in thin solid films of [4] chrysaorene by simple exposure to diiodine vapor.

Three chiral ligands with variable denticity, H2L2-H2L4, conjugated by N,N'-ethylenebis[N-methyl-(S)-alanine] and an ortho-heterosubstituted aromatic amine, were newly synthesized as analogues of previously reported H2L1. Four contracted-Λoxo cobalt(III) complexes [Co(L)](+) with left-handed helical structure of Λ4Δ2 configuration were prepared by one-electron oxidation of the corresponding contracted-Λred cobalt(II) complexes [Co(L)], which were generated from chiral ligands and Co(ClO4)2·6H2O or Co(CF3SO3)2·5.2H2O in the presence of an organic base. Although the prepared cobalt(III) complexes were very inert and kinetically stable against protonation and NO3(-) complexation, cobalt(III) reduction in the presence of CF3SO3H and/or Bu4NNO3 allowed immediate changing of their three-dimensional structures from the contracted-Λoxo form to the extended-Λ [Co(H2L)Y2](n+) (Y = solvent and/or anion, n = 0-2) form with left-handed helicity or to the extended-Δ [Co(H2L)(NO3)](+) form with right-handed helicity via N- to O-amide coordination switching. Both extended forms were contracted to the original Λoxo form by oxidation of the cobalt(II) center in the presence of an organic base. Thus, redox reactions triggered dynamic helicity inversion of the chiral cobalt complexes, via multiple molecular motions consisting of relaxation/compression, extension/contraction, and helicity inversion motions in combination with deprotonation/protonation of amide linkages and NO3(-) anion complexation.

The macrocyclic nonaaza 3 + 3 amine based on diaminocyclopentane forms enantiopure helical complexes with lanthanide(III) ions. In contrast to analogous complexes based on 1,2-trans-diaminocyclohexane, no clear helicity process is observed. Crystal structures of these compounds show tight helical wrapping of the macrocycle around the lanthanide(III) ion leading to the formation of a double helix. In contrast, more "open" conformation is observed for the free macrocycle. Similar double-helical conformation of the ligand was also observed for the lead(II) complex. In the case of this complex the NMR spectra indicate a dynamic process in which the C2-symmetric molecule observed in the solid state gives rise to an effective, averaged D3-symmetry in solution at elevated temperatures.

The reaction of trans-1,2-diaminocyclopentane with 2,6-diformylpyridine results in formation of 2 + 2, 3 + 3, and 4 + 4 Schiff base macrocycles as well as trace amounts of 6 + 6 and 8 + 8 macrocycles. In contrast, the 6 + 6 Schiff base macrocycle is a dominant product of the reaction of the isolated 2 + 2 macrocycle with excess of cadmium(II) chloride. The X-ray crystal structure of the protonated amine derivative of the 6 + 6 macrocycle reveals an unusual container-like conformation with the S6 axis.

The combination of 2,6-diformylpyridine and trans-1,2-diaminocyclopentane fragments results in 2 + 2, 3 + 3, 4 + 4, 6 + 6, and 8 + 8 macrocyclic imine condensation products. These imines can be reduced to the corresponding 2 + 2, 3 + 3, 4 + 4, 6 + 6, and 8 + 8 macrocyclic amines. The X-ray crystal structures of their protonated derivatives show a rich variety of macrocycle conformations ranging from a stepped 2 + 2 macrocycle to a multiply folded 8 + 8 macrocycle of globular shape. These compounds bind anions via hydrogen bonds: two chloride anions are bound above and below the macrocyclic ring of the 2 + 2 amine, one chloride anion is bound approximately in the center of the 3 + 3 macrocycle, and two chloride anions are deeply buried inside a folded container-shaped 4 + 4 macrocycle, while in the case of the previously reported 6 + 6 amine four chloride anions and two solvent molecules are buried inside a container-shaped macrocycle. Yet another situation was observed for a multiply folded protonated 8 + 8 macrocycle which binds six sulfate anions; two of them are deeply buried inside the container structure while four anions interact with the clefts at the surface of the container.

There is great interest in design and synthesis of small molecules which selectively target specific genes to inhibit biological functions in which particular DNA structures participate. Among these studies, chiral recognition has been received much attention because more evidences have shown that conversions of the chirality and diverse conformations of DNA are involved in a series of important life events. Here, we report that a pair of chiral helical macrocyclic lanthanide (III) complexes, (M)-Yb[L(SSSSSS)](3+) and (P)-Yb[L(RRRRRR)](3+), can enantioselectively bind to B-form DNA and show remarkably contrasting effects on GC-rich and AT-rich DNA. Neither of them can influence non-B-form DNA, nor quadruplex DNA stability. Our results clearly show that P-enantiomer stabilizes both poly(dG-dC)(2) and poly(dA-dT)(2) while M-enantiomer stabilizes poly(dA-dT)(2), however, destabilizes poly(dG-dC)(2). To our knowledge, this is the best example of chiral metal compounds with such contrasting preference on GC- and AT-DNA. Ligand selectively stabilizing or destabilizing DNA can interfere with protein-DNA interactions and potentially affect many crucial biological processes, such as DNA replication, transcription and repair. As such, bearing these unique capabilities, the chiral compounds reported here may shed light on the design of novel enantiomers targeting specific DNA with both sequence and conformation preference.

Cationic LnIII complexes with the chiral macrocycle L, (P)-[LnLRRRRRR]3+, interact with anionic LnIII tris(dipicolinate) complexes, [Ln′(dpa)3]3–, forming tight hydrogen-bonded ion pairs in solution. Formation of these pairs has been documented by the DFT calculations, and a strong paramagnetic shift of the signals of the diamagnetic cation interacting with the paramagnetic anion was observed. This ion pair interaction leads to spectral enantiodifferentiation of the Λ-[Ln′(dpa)3]3– and Δ-[Ln′(dpa)3]3– enantiomers of the anionic complex.Although no Pfeiffer effect was observed for the (P)-[LnLRRRRRR]3+ diastereomers of the cationic complex, the (M)-[LnLRRRRRR]3+ diastereomers induce CD signals in the anionic [Ln′(dpa)3]3– partner. These spectra indicate a Pfeiffer effect, i.e. a shift of equilibrium between the Λ-[Ln′(dpa)3]3– and Δ-[Ln′(dpa)3]3– enantiomers. This effect arises from the ion pair interaction between the anionic complex [Ln′(dpa)3]3– and the intact cationic complex as well as between [Ln′(dpa)3]3– and L. The protonated macrocycle (H3LRRRRRR)3+ forms highly insoluble salts with [Ln′(dpa)3]3–. These supramolecular compounds are formed by the reaction of L, acids and [Ln′(dpa)3]3– anions. The same product can also be formed by the reaction of (M)-[LnLRRRRRR]3+ with three equivalents of dipicolinic acid. The model structure of (H3LRRRRRR)[Ln′(dpa)3] corresponds with a linear polymer with alternate cationic macrocycles and anionic [Ln′(dpa)3]3– complexes interacting through charge interactions and multiple hydrogen bonds.

The La(III), Ce(III), Pr(III), Nd(III), Sm(III), and Eu(III) complexes of the racemic heterochiral nonaaza macrocyclic amine L have been synthesized and characterized by spectroscopic methods. The X-ray crystal structures of the [PrL][Pr(NO(3))(6)].CH(3)OH and the isomorphic [NdL][Nd(NO(3))(6)].CH(3)OH complexes show that all nine nitrogen atoms of the macrocycle coordinate to the Ln(3+) ion, completing its coordination sphere. The macrocycle wraps tightly around the metal ion in double-helical fashion. The structures reveal the RRRRSS/SSSSRR configuration at the stereogenic carbon atoms of the three cyclohexane rings, confirming the heterochiral nature of the parent 3 + 3 macrocycle obtained in the condensation of racemic trans-1,2-diaminocyclohexane and 2,6-diformylpyridine. The NMR spectra of the isolated complexes indicate the presence of low C(1) symmetry [LnL](3+) complexes. The same symmetry is indicated by the X-ray crystal structures of Pr(III) and Nd(III) complexes, which show that for the RRRRSS enantiomer of the macrocycle L, the helix axis passes through the cyclohexane ring of RR chirality and the opposite pyridine ring. The NMR studies of complex formation in solution by the paramagnetic Pr(3+) and Eu(3+) ions indicate that the initially formed [LnL](3+) complexes are of C(2) symmetry. For the RRRRSS enantiomer of the macrocycle L in the C(2)-symmetric species, the helix axis passes through the cyclohexane ring of SS chirality and the opposite pyridine ring. The C(1)-symmetric and C(2)-symmetric forms of the [LnL](3+) complexes constitute a new kind of isomers and the conversion of the kinetic complexation product of C(2) symmetry into the thermodynamic product of C(1) symmetry corresponds to an unprecedented switching of the orientation of the helix axis within the macrocycle framework.

Z-Selective Wittig olefination was applied to the synthesis of large carbazolophanes containing up to eight heteroaromatic subunits. A number of strategies were devised and tested, showing that cyclooligomerization yields can be significantly improved by using one-component schemes involving heterobifunctional reactants. [4]- and [6]Carbazolophanes were characterized in the solid state, revealing compact, highly folded structures. Electronic and steric effects of substitution and chain length on the Wittig olefination rates and Z-selectivities were explored theoretically using DFT calculations.

The [LnL](NO3)3 · nH2O complexes of the series of all lanthanide(III) ions, except radioactive Pm, with the meso-type hexaazamacrocycle L, derived from racemic trans-1,2-diaminocyclohexane and 2,6-diformylpyridine, have been synthesised and characterized. The X-ray crystal structures of the isomorphic La(III) and Sm(III) complexes show that the lanthanide(III) ions are coordinated by six nitrogen atoms of the relatively flat macrocycle L as well as by two axial bidentate nitrate anions and methanol molecule. The complexes have been characterised by NMR spectroscopy and mass spectrometry. 1H NMR signals of the Ce+3, Pr+3, Nd+3, Eu+3 and Yb+3 complexes have been assigned on the basis of the COSY and HMQC spectra, and for the remaining lanthanide complexes the signals were assigned on the basis of linewidths analysis. The paramagnetic shifts of the series of lanthanide complexes [LnL](NO3)3 · nH2O have been analysed using both crystal-field dependent and independent methods. The results of this analysis indicate a change of coordination number along the series of Ln(III) complexes. The properties and stability of the lanthanide(III) complexes of the macrocycle L have been compared with those of the isomeric chiral macrocycle L1.

The new enantiopure complexes [LnL](NO 3 ) 3 · n H 2 O (Ln = Dy +3 , Ho +3 , Er +3 , Lu +3 ) and [LnL]Cl 3 · n H 2 O (Ln = Nd +3 , Sm +3 , Gd +3 , Tb +3 , Dy +3 , Ho +3 , Er +3 , Tm +3 , Lu +3 ) of the chiral macrocycle L derived from (1R,2R)-1,2-diaminocyclohexane and 2,6-diformylpyridine have been synthesised. The preference of macrocycle L for the heavier lanthanide(III) ions has been established on the basis of competition reaction. The complexes have been characterised by NMR spectroscopy and mass spectrometry. 1 H NMR signals of deuterated water solutions of the Ce +3 , Nd +3 and Eu +3 complexes have been assigned on the basis of the COSY and HMQC spectra, and for the remaining lanthanide complexes the signals were assigned on the basis of linewidths analysis. The paramagnetic shifts of the series of lanthanide complexes [LnL](NO 3 ) 3 · n H 2 O and [LnL]Cl 3 · n H 2 O have been analysed using both crystal-field dependent and independent methods in order to separate contact and dipolar contributions and establish isostructurality along the series of lanthanide complexes in solution. The data obtained for nitrate derivatives in organic solvent indicate rather irregular deviations from the plots based on those methods, while the plots obtained for water solutions show the characteristic brake in the middle of the lanthanide series, that is interpreted as a result of change of the number of axially coordinated water molecules. The apparent inconsistencies of results obtained on the basis of crystal-field independent method are discussed.

The chiral nonaazamacrocyclic amine L, which is a reduction product of the 3 + 3 Schiff base macrocycle, wraps around the lanthanide(III) ions to form enantiopure helical complexes. These Ce(III), Pr(III), Nd(III), Eu(III), Gd(III), Tb(III), Er(III), Yb(III) and Lu(III) complexes have been isolated in enantiopure form and have been characterized by spectroscopic methods. X-ray crystal structures of the Ln(III) complexes with L show that the thermodynamic product of the complexation of the RRRRRR-isomer of the macrocycle is the (M)-helical complex in the case of Ce(III), Pr(III), Nd(III) and Eu(III). In contrast, the (P)-helical complex is the thermodynamic product in the case of Yb(III) and Lu(III). The NMR and CD spectra show that the (M)-helicity for the kinetic complexation product of the RRRRRR-isomer of the macrocycle is preferred for all investigated lanthanide(III) ions, while the preferred helicity of the thermodynamic product is (M) for the early lanthanide(III) ions and (P) for the late lanthanide(III) ions. In the case of the late lanthanide(III) ions, a slow inversion of helicity between the kinetic (M)-helical product and the thermodynamic (P)-helical product is observed in solution. For Er(III), Yb(III) and Lu(III) both forms have been isolated in pure form and characterized by NMR and CD. The analysis of 2D NMR spectra of the Lu(III) complex reveals the NOE correlations that prove that the helical structure is retained in solution. The NMR spectra also reveal large isotopic effect on the 1H NMR shifts of paramagnetic Ln(III) complexes, related to NH/ND exchange. Photophysical measurements show that L(RRRRRR) appears to favor an efficient 3pipi*-to-Ln energy transfer process taking place for Eu(III) and Tb(III), but these Eu(III)- and Tb(III)-containing complexes with L(RRRRRR) lead to small luminescent quantum yields due to an incomplete intersystem crossing (isc) transfer, a weak efficiency of the luminescence sensitization by the ligand, and/or efficient nonradiative deactivation processes. Circularly polarized luminescence on the MeOH solutions of Eu(III) and Tb(III) complexes confirms the presence of stable chiral emitting species and the observation of almost perfect mirror-image CPL spectra for these compounds with both enantiomeric forms of L.

Lanthanide(III) complexes of the enantiopure chiral hexaaza tetraamine macrocycle L, 2(R),7(R),18(R),23(R)-1,8,15,17,24,31-hexaazatricyclo[25.3.1.1.0.0]-dotriaconta-10,12,14,26,28,30-hexaene, as well as of its meso-type 2(R),7(R),18(S),23(S)-isomeric macrocycle L1, have been synthesized and characterized by spectroscopic methods. The 2D NMR spectra confirm the identity of these complexes and indicate C2 symmetry of the [LnL]3+ and Cs symmetry of the [LnL1]3+ complexes. The crystal structures of the [PrL(NO3)(H2O)2](NO3)2, [EuL(NO3)(H2O)2](NO3)2, [DyL(NO3)2]2[Dy(NO3)5] x 5CH3CN, [YbL(NO3)2]2[Yb(NO3)5] x 5CH3CN, [YbL(H2O)2](NO3)3 x H2O, and [EuL1(NO3)(H2O)2]0.52[EuL1(NO3)2]0.48(NO3)1.52 x 0.48H2O complexes have been determined by single-crystal X-ray diffraction. In all complexes, the lanthanide(III) ions are coordinated by six nitrogen atoms of the macrocycle L or L1, but for each type of complex, the conformation of the macrocycle and the axial ligation are different. The crystallographic, NMR, and CD data show that the [YbL]3+ complex exists in two stable forms. Both forms of the Yb(III) complex have been isolated, and their interconversion was studied in various solvents. The two forms of [YbL]3+ complex correspond to two diastereomers of ligand L, which differ in the sense of the helical twist and the configuration at the stereogenic amine nitrogen atoms. In one of the stereoisomers, the macrocycle L of (RRRR) configuration at the stereogenic cyclohexane carbon atoms adopts the (RSRS) configuration at the amine nitrogen atoms, while in the other stereoisomer, the macrocycle L of (RRRR) configuration at the stereogenic cyclohexane carbon atoms adopts the (SSSS) configuration at the amine nitrogen atoms. The (RRRR)(RSRS) isomer is quantitatively converting to the (RRRR)(SSSS) isomer in water solution, while the reverse process is observed for an acetonitrile solution, thus representing the rare case of helicity inversion controlled by the solvent.

Two new Schiff base macrocycles - a 4+4 condensation product and a meso-type 2+2 condensation product - were obtained in a reaction of trans-1,2-diaminocyclohexane and 2,6-diformylpyridine. Reduction of these compounds led to the corresponding 4+4 and 2+2 macrocyclic amines. The macrocycles were characterised by NMR spectroscopy and electrospray mass spectrometry. The symmetry and stereochemistry of these macrocycles, as well as of new 3+3 and 4+4 diastereomers identified in solution, has been established. X-Ray structures of the 2+2 and 4+4 Schiff base macrocycles confirm the configurations determined on the basis of spectroscopic investigations. The crystal structures reveal that the centres of the square-shaped 4+4 macrocycles form channels as a result of columnar stacking.