Sarcophagines

Treatment of [Co MeC(CH2Se(CH2)2NH2)3 ]Cl3 with HCHO and MeN02 gives a rare example of a mixed N3Se3-donor sarcophagine ligand complex.109... 

In aqueous solution it exhibits a chemically reversible Cr(III) — Cr(II) reduction ( 0, = -1.35 V A p = 70mV, at 0.05 V s-1).34 This indicates that, contrary to the previous scorpiands, the sarcophagine cavity is sufficiently large (or the molecular structure sufficiently flexible) to host the electrogenerated Cr(II) ion without significant structural strains. 

Another cobalt derivative with CoN6 coordination is [Co(sep)]3+. This is the complex formed by Co(III) with the ligand 1,3,6,8, 10,13,l,6,19-octaazabicyclo[6.6.6]eicosane, which is related to the diamino-sarcophagine seen for the chromium complexes, and is called sepulcrand . Figure 90 shows the octahedral structure of this complex.135... 

Sapphire polycrystals from radio-frequency plasma, 17 105, 106 Sarcophagine, 35 153 Sarin, hydrolysis of, 7 224-225 SIOOB, 46 453-454, 455 SlOOb, 46 453 54 SbBr, 41 235... 

Fig. 30. Schematic formation of the D3-symmetrical complexes [i (L7-2H)3]3 in water with numbering scheme. The representation of [i (L7-2H)3]3 corresponds to the crystal structure of [Cr(sarcophagine)][La(L7-2H)](Fl20)8...

Keywords Anion coordination chemistry Cryptands Ligands Metal coordination chemistry Molecular recognition Receptors Sarcophagines... 

From Ammonia to Sarcophagine Cages for Metals Made by Metals. 129... 

Fig. 3 Evolution of ligands containing sp3 nitrogen donor atoms from ammonia, to ethylenediamine, to cyclam, to sarcophagine...

Fig. 10 Different cobalt sarcophagine complexes 5-7 derived from the [Conl(N02)2sar]3+ precursor 4, obtained from a template reaction...

Fig. II Top Structures of metal complexes of sarcophagines, as obtained from X-ray diffraction studies [25-28] Cr is complexed by (NH2)2sar all other metals are complexed by (NH3)2sar2+. Bottom Top view of the triangles obtained by joining the nitrogen atoms of the secondary amine groups linked to each one of the two caps of sarcophagine ligands, with the values of torsion angles 6...

The smallest bistren derivative contains -CH2CH2- spacers (18, see Fig. 29) and is reminiscent of Sargeson s polyamine cages sepulchrand and sarcophagine, in that... 

The stability of [Co(am)6]3+ complexes allows the template construction of tricyclic ligands around the metal ion. An example is the sarcophagine complex (17-F-I) in which the metal center is irreversibly encapsulated but retains its redox activity. With suitable substituents, such complexes can act as intercalators in DNA or as photosensitizers.14... 

Symbols of the apical substituents in the capping fragments of sarcophaginates and sepulchrates. 

In some cases, a free clathrochelate ligand has been isolated after its template construction on the metal ion and demetallation of the resultant complexes. In particular, this has made it possible to synthesize sarcophaginates of many metals incapable of forming clathrochelates via direct template synthesis they are formed from... 

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