1,10-Phenanthroline-containing ring

Molecular motion based on the electrochemical-induced ligand substitution reaction has been reported in a copper(I) rotaxane (Figure 37). This rotaxane is composed of a 2,9-diphenyl-l,10-phenanthroline-containing cyclic poly ether ring, a tetraphenylmethane-stoppered molecular string that contains another 2,9-disubstitnted phenanthroline chelate... 

In this study, we report synthesis of a new thiourea derivative (2) which contain crown ether and phenanthroline ring by the reaction of 5-amino-1,10-phenanthro-line with 15-isothiocyanatobenzo[15-crown-5] (1) (Fig. 43.1) and its complex with Cu(I) is obtained. The structures of the ligand and the complex were determined by their elemental analysis, UV-vis, FTIR, H NMR (DMSO-d ), C NMR (DMSO-dg) and Mass spectra (LC-MS). 

Other important ligands include those based upon the diazafluorene structure <2000JST91>. It has been shown that the coordination behavior of complexes containing the diazafluorene ring system is quite different to that of the parent 2,2 -bipyridyl or 1,10-phenanthroline systems, and evidence for unsymmetrical chelation has been observed <1998POL2463, 1996IC2253>. 

The molecular axis contains a thin 2,2 -bipyridine motif, which is less bulky than a 1,10-phenanthroline fragment and thus is expected to spin more readily within the cavity of the ring. In addition, the bipy chelate does not bear substituents in -position to the nitrogen atoms. 5(4) + rearranges to the five-coordinate species 5(5)2+ after oxidation and vice versa. The electrochemically driven motions were studied by cyclic voltammetry. A lower limit for the rate constant of the... 

A second molecular shuttle 10(4) +, has been synthesized in our group38 and is represented in Fig. 14.15. The mobile ring is the nonhindering 39-membered ring 9 containing one 8,8 -diphenyl-3,3 -biisoquinoline chelate, and its linear part contains, as in previous molecular shuttle 7(4)+, one bidentate 1,10-phenanthroline and one tridentate terpyridine units. Another difference is the phenylene group as a linker, which makes this thread more rigid. 

Several compounds and their derivatives that do not contain adjacent hydroxy groups on a phenyl ring have recently been identified as HIV integrase inhibitors. These include suramin (X), curcumin (XI), phenanthroline-Cu+ complexes (XII), and 3 -azido-3 -deoxythymidylate (AZT) monophosphate (XIII). 

Cerium tetrakis(acetylacetonate), a venerable compound,695 exists as a and /3 modifications. Both these contain [Ce(acac)4] monomers of D2 square antiprismatic coordination but differ in the crystal packing. In the a form,696 Ce—0 = 2.36-2.43 A with the ring angle O—Ce— 0 = 72°, while in the / form697 Ce—0 = 2.32 A and O—Ce—0 = 71.3°. The tetrakis(acetyl-acetonates) of Zr, Hf, Th, U and Pu also show dimorphism. The tetrakis(dibenzoylmethanate) [Ce(dbm)4] adopts a similar square antiprismatic structure with Ce—O = 2.299-2.363 A and O—Ce—O = 70.8° or 71,2°.698 There is some tendency for Ce3+ /J-diketonates to pass into the Ce4+ tetrakis(/3-diketonate). A series of tri- and tetra-valent cerium /3-diketonates has been examined from the point of view of the effect of additional ligands such as Ph3PO on this process, and it was found that Ce3+ /J-diketonates were stabilized by adduct formation, particularly by 1,10-phenanthroline.699... 

Four chapters in the present volume bring older reviews up to date. Those on the quinoxalines (Cheeseman and Werstiuk) and on hetero-aromatic quaternization (Zoltewicz and Deady) carry forward contributions on the same subjects in Volumes 2 (1963) and 3 (1964), respectively, of this Series, while those on the phenanthrolines (L. A. Summers) and the isatogens and indolones (Hiremath and Hooper) deal with topics previously covered elsewhere. The cyclazines, a relatively new field of chemistry, are reviewed by Flitsch and Kramer, and the azapentalenes— the wide variety of nitrogen-containing heterocycles formed by the fusion of two aromatic five-membered rings—are collected into one chapter by Elguero, Claramunt, and A. J. H. Summers. 

Chelate rings can be formed by pyridines containing a-substituents such as carboxyl or CH = NR. Important bicyclic chelating agents are 2,2 -bipyridyl (55 Y = H), o-phenanthroline (56) and... 

Numerous macrocyclic and macropolycyclic ligands featuring subheterocyclic rings such as pyridine, furan or thiophene have been investigated [2.70] among which one may, for instance, cite the cyclic hexapyridine torands (see 19) [2.39] and the cryptands containing pyridine, 2,2 -bipyridine (bipy), 9,10-phenanthroline (phen) etc. units [2.56,2.57,2.71-2.73]. The [Na+ c tris-bipy] cryptate 20 [2.71] and especially lanthanide complexes of the same class have been extensively studied [2.74, 2.75] (see also Sect. 8.2). 

Chelate complexes. Chelate rings can be formed by pyridines containing -substituents such as carboxyl or CH=NR. Important bicyclic chelating agents are 2,2-bipyridyl 68 (R = H), o-phenanthroline 69 and 8-hydroxyquinoline 70, which all form bis and tris complexes with many metals <1994CSR327>. This type of complex formation has many analytical applications. Overlap between the d-orbitals of the metal atom and the pyridine -orbitals is believed to increase the stability of many of these complexes. Steric effects can hinder complex formation as in 68 (R = Me). 

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