Macrotricyclic ligands

Ni1 complexes (944)-(950) with various different saturated polyaza macrotricyclic ligands having noncoordinated nitrogen atoms in the ligand framework have been prepared by reduction of the Ni11 complexes with Na/Hg in acetonitrile. The crystal and molecular structures of (948), (946), and (945) were determined.1582,2333 Both complexes were found to have essentially square... 

The macrotricyclic ligands (240) and (241) may be synthesized by multistep high-dilution procedures (Graf Lehn, 1975). They contain spherical cavities which are able to accommodate suitable guests whether they be cationic, neutral, or anionic. 

Fig. 4. Synthetic strategies towards macrotricyclic ligands of type J...

Table 6. Approximate cavity diameters in macrocyclic, macrobicyclic and macrotricyclic ligands...

Various evidence shows that the macrotricyclic ligand 45 forms 1 1 inclusion complexes, [3]-cryptates, with AC s and AEC s (96). NMR spectroscopic data indicate that the cation is non-symmetrically located in the cavity (95). 1 2 complexes with two Ag+ or T1+ cations have also been observed (Pd). Complex formation of ligand 46 with K+, Na+, Li+ and Ca++ has been reported (92). 

In cases where nitroethane is used instead of methylamine as shown in Eq. (4), the Ni(II) complex of hexaaza macrotricyclic ligand, L2, can be prepared (19). 

Properties of Square-Planar Nickel(II) Complexes of AT-Alkylated Macrotricyclic Ligands... 

E. Graf, J.-M Lehn, Synthesis and ciyptate complexes of a spheroidal macrotricyclic ligand with octahedrotetrahedral coordination. J. Am. Chem. Soc. 1975, 97, 5022-5024. 

The first cylindrical macrotricyclic ligands synthesized were (52a) and SSa-d).58 70 Cryptands in which the two monocycles are even farther apart as a result of bridging naphthyl, biphenyl and. related groups have also been reported.188,1 9 The smaller macrocycle (52a) forms complexes with a variety of metal cations, including two silver(I) ions.69,70 190 Crystal data results for the latter complex indicate both Ag+ ions are located slightly out of the plane of the macrocycles (undoubtedly the result of macrocyclic size constraints), but within the central main cavity, with an Ag—Ag distance of 3.88 A.191... 

The spherical macrotricyclic ligands are also particularly suited for tetrahedral recognition by virtue of the location of the nitrogens. This aspect will be discussed in Section 21.3.8. 

Fig. 33. A potential iono- or mechano-electroswitch based on a heterotopic macrotricyclic ligand the electrochemical interconversion of a copper ion could switch the location of the ion from the [12J-N2S2 ring in the Cu(l) state (left) to the [15]-N2C>3 subunit in the Cu(li) state (right).

Metz, B., Rosalky, J. M., Weiss, R., [3] Cryptates - X-ray crystal-structures of chloride and ammonium ion complexes of a spheroidal macrotricyclic ligand. J. Chem. Soc., Chem. Commun. 1976, 533-534. 

Macrotricyclic cryptates may have either spherical or cylindrical topology (90). The cylindrical ligands, such as 5, are formed by linking together two macrocycles and define three cavities, two lateral and one central cavity inside the macrotricycle (18,19,91, 92). The macrotricyclic ligands of spherical topology are Particularly well suited for com-plexation of alkali cations as they define a spherical cavity (93, 94). Ligand 10, for example, contains a spherical cavity (diameter 3.4 A)... 

Adamantyl)thiacalix[4]arene was synthesized either by condensation of p- 1 -adamantyl)-phenol with sulfur in the presence of base or alkylation of p-//-thiacalix[4]arene with adamantanol in F3CCO2H <02TL5153>. A new macrotricyclic ligand with an N4S2 donor set has been synthesized from cyclam it was shown to encapsulate lithium and transition metal ions <02CC170>. 

Lehn and coworkers have performed a chiral recognition study using the macrotricyclic ligand (54) which incorporates a binaphthyl unit481 (Scheme 16). Two modes of complexation may occur in solution for ligand 54 ... 

Macrotricyclic ligands have also been prepared, e.g. the structures shown in Fig. 7047 186 Both compounds form complexes ([3]cryptates) with alkali and other cations. The lower alkali ion selectivity and complex stability of [3] cryptand 1 in comparison to [2] cryptands is probably due to the larger size of its cavity which has a length of approximately 6 A47-. The cavity of ligand 1 can even accommodate two cations which has been demonstrated by X-ray analysis of a LAg2+ complex (L = ligand 1,... 

Fig. 71. X-ray resolved structures of two complexes of the macrotricyclic ligand 2 (Fig. 70). a, the [LNH4]+ complex b, the [C1LH4]3+ complex (L = ligand)...

Synthesis of diaza-polyoxa-macrobicyclic compounds (cryptands) and spherical macrotricycles ligands (supercryptands) (see 1st edition). 

Both 1 1 and 1 2 complexes of the novel tetra-azahexaoxa-macrotricyclic ligand (83) have been observed in CDCI3 solution, and the L,2AgN03 species... 

Extensive studies on metal (Ni or Fe) promoted oxidative dehydrogenations of this and related systems have been reported, the latter paper containing a note on the nomenclature of these complexes which appears to have become rather confused. Related complexes,a new synthesis of cyclam as its Ni complex, and an investigation of Li salt complexes of cyclam by i.r. measurements have also been reported. Mononuclear cryptates, with a wide variety of metal iodides and chlorides, and dinuclear cryptates, with AgN03 and HCOgTl, involvingthe macrotricyclic ligand (500) are discussed. 8i... 

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