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Four new N2O2-donor macrocycles mDo4R, mDo5R, mDo6R, mDo7R (mDo4R = 1,5-diaza-2,4:7,8:15,16- tribenzo-9,14-dioxa-cycloheptadecane, mDo5R = 1,5-diaza-2,4:7,8:16,17-tribenzo-9,15-dioxa-cyclooctadecane, mDo6R = 1,5-diaza-2,4:7,8:17,18-tribenzo-9,16-dioxa-cyclononadecane; mDo7R = 1,5-diaza-2,4:7,8:18,19-tribenzo-9,17-dioxa-cycloeicosane) were prepared...
Citations
... In order for macrocyclic ligands to bind successfully to certain chemical species, it is important to consider several different factors, such as the size of the macrocyclic ring, the properties of the donor atoms, the substituents in the ring, the properties of the metal ions (ionic radius, hardness or softness), the polarity of the system, and the orientation of donor atoms (exo or endo) [6][7][8][9]. The fundamental characteristic of macrocyclic complexes is increased thermodynamic stability compared to analogous acyclic complexes. ...
... Two adjacent polymeric chains are connected by π···π interactions between benzene rings (Cg2 (C8→C13) ··· Cg3 (C19→C24)) approximately along [1][2][3][4][5][6][7][8][9][10][11] crystallographic directions. These aromatic interactions are observed only in AgLSbF 6 and are the consequence of macrocyclic ring flattening. ...
... Symmetry operation: #1 ½ + x, 3/2 -y, −1/2 + z. Disordered dichloromethane and chloroform molecules are omitted for clarity.Two adjacent polymeric chains are connected by π‧‧‧π interactions between benzene rings (Cg2 (C8→C13) ••• Cg3 (C19→C24)) approximately along[1][2][3][4][5][6][7][8][9][10][11] crystallographic directions. These aromatic interactions are observed only in AgLSbF6 and are the consequence of macrocyclic ring flattening. ...
Silver(I) complexes with aza-oxa macrocyclic Schiff bases L (L = 1,5-diaza-2,4:7,8:16,17-tribenzo-9,15-dioxa-cyclooctadeca-1,5-dien) were prepared by the reaction of the corresponding macrocycle with four different silver salts (AgX; X = ClO4, PF6, SbF6 and BF4). In all four compounds, silver ions are exo-coordinated by two neighboring ligand molecules in linear and T-shaped geometries. Such a coordination mode results in the formation of infinite 1D polymeric chains. Compounds AgLClO4 and AgLBF4 are isostructural, and polymeric chains display 1D zigzag topology. In AgLPF6 there are three symmetrically unique Ag ions in the asymmetric unit of the compound. Two silver ions are linearly coordinated with two neighboring ligand molecules and are part of a discrete polymer chain. The third silver ion is coordinated with two ligand molecules and a methanol molecule in a T-shaped geometry. Such coordination geometry results in the formation of two discrete infinite polymer chains in the crystal structure. In the AgLSbF6 compound, the chain topology is a linear zigzag chain, but in this compound, there is a difference in the orientation of the Ag-N bond. The Ag-N-Ag bonds are in the trans position relative to the plane calculated through the ligand molecule, while the Ag-N bonds are in the cis position in all other compounds. Due to the presence of a bulky SbF6 anion, the ligand molecule is planar compared to other compounds. Considering intermolecular interactions, there is a huge variety of different interactions, mostly depending on the type of anion. A general supramolecular motif in all compounds is best described as 2D sheets of ligand–metal polymers with anions and solvent molecules sandwiched between them. In addition, the obtained compounds were characterized by IR spectroscopy and thermal analysis. The TG analysis indicates a rather surprising and considerable thermal stability of the prepared compounds, with some compounds thermally stable over 300 °C.
... It is also important to emphasize that the change in chain length can be used to manipulate the size of the binding space in the macrocyclic system, and thus, to modify the binding affinity towards different chemical species. As previously described by our group in the case of dialdehydes, these subtle changes in the chain length can lead to the different extraction properties of macrocycles [2,3]. Further on, such changes result in diverse conformations of macrocycles, with an important impact on the dimensionality and supramolecular assembly of coordination compounds [4]. ...
The century-old, well-known odd–even effect phenomenon is still a very attractive and intriguing topic in supramolecular and nano-scale organic chemistry. As a part of our continuous efforts in the study of supramolecular chemistry, we have prepared three novel aromatic alcohols (1,2-bis [2-(hydroxymethyl)phenoxy]butylene (Do4OH), 1,2-bis[2-(hydroxymethyl)phenoxy]pentylene (Do5OH) and 1,2-bis[2-(hydroxymethyl)phenoxy]hexylene (Do6OH)) and determined their crystal and molecular structures by single-crystal X-ray diffraction. In all compounds, two benzyl alcohol groups are linked by an aliphatic chain of different lengths (CH2)n; n = 4, 5 and 6. The major differences in the molecular structures were found in the overall planarity of the molecules and the conformation of the aliphatic chain. Molecules with an even number of CH2 groups tend to be planar with an all-trans conformation of the aliphatic chain, while the odd-numbered molecule is non-planar, with partial gauche conformation. A direct consequence of these structural differences is visible in the melting points—odd-numbered compounds of a particular series display systematically lower melting points. Crystal and molecular structures were additionally studied by the theoretical calculations and the melting points were correlated with packing density and the number of CH2 groups. The results have shown that the generally accepted rule, higher density = higher stability = higher melting point, could not be applied to these compounds. It was found that the denser packaging causes an increase in the percentage of repulsive H‧‧‧H interactions, thereby reducing the stability of the crystal, and consequently, the melting points. Another interesting consequence of different molecular structures is their electrochemical and antioxidative properties—a non-planar structure displays the highest oxidation peak of hydroxyl groups and moderate antioxidant activity.
... Relatively small changes in the size of the macrocyclic ring containing the same functional groups may cause large changes in its conformation, and thus the structure in the crystalline phase in the properties caused by the different spatial arrangement of the donor atoms in the macrocycle ring [20]. ...
Macrocyclic nitrogen-containing compounds are versatile molecules. Supramolecular, noncovalent interactions of these macrocycles with guest molecules enables them to act as catalysts, fluorescent sensors, chiral or nonchiral selectors, or receptors of small molecules. In the solid state, they often display a propensity to form inclusion compounds. All of these properties are usually closely connected with the presence of nitrogen atoms in the macrocyclic ring. As most of the reviews published so far on macrocycles were written from the viewpoint of functional groups, synthetic methods, or the structure, search methods for literature reports in terms of the physicochemical properties of these compounds may be unobvious. In this minireview, the emphasis was put on the synthesis and applications of nitrogen-containing macrocyclic compounds, as they differ from their acyclic analogs, and at the same time are the driving force for further research.
... Shape-persistent macrocycles can be synthesized by several different strategies [15][16][17]; one of the most straightforward approaches is the cyclocondensation of suitable aldehyde and amine precursors which results in the formation of imine (Schiff base) porous compounds. Synthesis of porous macrocycles through Schiff base chemistry holds several advantages: (i) no need for catalysts, (ii) high yields, (iii) self-correction and (iv) a robust mechanism enabling the preparation of novel macrocycles [18,19]. ...
The removal and detection of highly toxic and environmentally harmful gases such as SO2, H2S and CO2 is a hot topic of the scientific community. Porous organic compounds, in particular, imine-based macrocycles, are promising materials for this purpose. In this paper we have used porous N4O4-donor macrocyclic Schiff base (1,6,20,25-tetraaza-2,5:8,9:17,18:21,24:27,28:36,37-hexabenzo-10,16,29,35-tetraoxa-cyclooctatriakonta-1,6,20,25-tetraen) (1) for sorption of NH3, SO2, Cl2, CO2 and H2S. Five novel inclusion compounds 1xNH3, 1xSO2, 1xCl2, 1xCO2 and 1xH2S were prepared by a single-crystal to single-crystal (SC-SC) transformation. Single-crystal X-ray diffraction (SCXRD) analysis of 1xCO2 and 1xNH3 inclusion compounds have shown that CO2 molecule resides in the plane of the macrocyclic ring connected by weak C–O … π interactions to the host, and no host-guest interactions in 1xNH3 were observed. The relative thermal stabilities of the host-guest systems (Ton – Tb parameter) is in the range from 93 (1xNH3) to 132 °C (1xH2S), indicating the formation of stable inclusion compounds. Although used gases are highly reactive and corrosive, FT-IR and powder diffraction studies indicate that the molecular and crystal structure of the host is constant upon gas sorption. The activated compound displays moderate uptake (0.35 mmol/g) of CO2 at 298 K. The relatively high thermal stability, constant molecular and crystal structure of inclusion compounds with interesting optical properties (determined by solid state UV–Vis) make this material potentially useful for the detection of toxic gases.
Three novel silver(I) complexes with N2O2-donor macrocyclic Schiff bases L1 and L2 (L1 = 1,5-diaza-2,4:7,8:17,18-tribenzo-9,16-dioxa-cyclononadeca-1,5-dien; L2 = 1,5-diaza-2,4:7,8:18,19- tribenzo-9,17-dioxa-cycloeicosa-1,5-dien) were prepared by the reaction of the corresponding macrocycles with silver nitrate and silver perchlorate in 1:1 stoichiometric ratio. The reactions of macrocyclic ligands (L1 and L2) with silver perchlorate led to the formation of unusual (regarding donor set atoms) silver coordination polymers, AgL1ClO4, and (AgL2ClO4)2·CH2Cl2. The reaction of L2 with silver nitrate resulted in a formation of discrete binuclear silver complex (AgL2NO3)2. In all three compounds, silver ions are exo-coordinated due to the presence of rigid CN bond in the molecular structure of ligands in which nitrogen atom non-bonding electron pairs are exo- oriented. All synthesized compounds were characterized by vibrational spectroscopy (IR) and thermal methods (TG/DSC). The crystal and molecular structures of silver complexes were determined by the single crystal X-ray diffraction method. In the complex AgL1ClO4, each silver atom is coordinated by two ligand molecules and one perchlorate anion (T-shaped geometry). The coordination geometry around the silver atom can be described as T-shaped, resulting in a formation of the 1D zig-zag polymeric chain. In (AgL2ClO4)2·CH2Cl2 two distinct coordination surroundings of silver ions that can be divided into cationic (linear geometry) and anionic (square planar geometry) part. The topology of the polymeric chain can be described as a 1D zig-zag. The silver atoms in (AgL2NO3)2 are tetrahedrally coordinated with two N-bound ligand molecules and one nitrate anion (bidentate). This form of coordination produces a discrete bimetallic silver complex with an additional metallacyclic ring. The anion and ligand influence on the chain structure is attributed to the presence of rigid imine double bond and partly to the coordination ability of counter ions.
