Anthracene spacer

The synthesis of 9,10-bis(l,3-dithiol-2-ylidene)-9,10-dihydroanthracene derivatives bearing two alkoxy chains attached to the anthracene spacer was also reported <2000EJ01199>. 

The distance dependencies of photoinduced electron transfer rates have been examined in anthracene-spacered porphyrin-quinone cyclophanes, and the same authors have also discussed the distance dependencies of photo-induced electron-transfer rates in benzene-, naphthalene-, and anthracene-spacered porphyrin-quinone cyclophanes and biphenylene-spacered porphyrin-quinone cyclophanes. Photoelectron transfer reactions of the porphyrin-quinone cyclophanes (3) and their zinc complexes have been examined, and in some cases at least interaction of the quinone carbonyl group with the zinc atom may be an alternative to through-space electron transfer. A study of intramolecular photoinduced electron transfer for the quinone-porphyrin cyclophane type (4) containing the especially strong acceptor 7,7,8,8-tetracyanoquinodimethane (TCNQ) has appeared." The distance dependence of the TCNQ and porphyrin is of particular interest, and to this end the corresponding 2,8-naphthalenediyl-TCNQ-porphyrin has been synthesised. 

Another unique dimeric system was first reported by Naruta and Maruyama in 1991 (443-445). In this system, two MnIU-porphyrin molecules are linked by an anthracene spacer instead of the o-phenyl-ene spacer seen in Fig. 75 (discussed later). Their studies showed this... 

Fig. 25. H-bonded main-chain polymers incorporating recognition groups 1 and 2 linked to a flexible chiral tartaric acid spacer (35, 36) or to a rigid anthracene spacer (37, 38)...

Anthracene-diresorcinol derivative 29 [50-52] is an in-plane tetraol, having an inclined or orthogonal anthracene spacer (Fig. 9). It forms a hydrogen-bon-... 

Recently, Kadish et al. synthesized three series of Co corroles (shown in Figure 4.11(D)) and investigated their catalytic activity toward the O2 reduction reaction.The mixed valent Co(II)/ Co(III) complexes, (PCY)Co2, and the biscorrole complexes, (BCY)Co2, both contain two Co(III) ions in their air-stable forms. It was foimd that all these complexes could catalyze the direct four-electron pathway for O2 reduction to H2O in aqueous acidic electrolyte. The most efficient catalysis process was observed when the complex had an anthracene spacer. The four-electron transfer pathway was further confirmed by RRDE measurement, in which only a relatively small amount of hydrogen peroxide was detected at the ring electrode in the vicinity of E1/2 0.47 V vs SCE for (PCA)Co2 and 0.39 V for (BCA)Co2. The cobalt(III) mono-corrole, (Me4Ph5Cor)Co, could also catalyze ORR at En2 = 0.38 V, with the final products being an approximate 50% mixture of H2O2 and H2O. 

A similar ligand syntone 339 with a 1,10-anthracene spacer liagment has been assembled with zinc and cobalt(II) ions by Scheme 4.113 to give M4L6 capsules 662 and 663 [110], The cage complex of 662 with encapsulated tetrafluo-roborate anion has a non-crystallographic T symmetry caused by the same chirality of its vertex... 

Fig. 6 Typical PET probes (a) and representative fluorescence light-up responses toward selected metal ions in tabulated (b) and graphical form (c trace 1 = 14, trace 2 = 14-(Zn2+)2, trace DMA = 9,10-dimethylanthracene in MeCN). Color code coordinating atoms in blue, atoms which take part in the complexation and show (main, in 14) PET activity in orange, fluorophore in green. Lincoln and co-workers have demonstrated that the attachment of two dimethylamino groups through propylene spacers to the 9,10-positions of anthracene has a more than 100-fold weaker PET activity than the attachment through methylene spacers [62]. The blue N atoms in 14 are thus predominantly responsible for coordination. For symbols, see Fig. 3. Quantum yield of 14 in MeCN estimated from intensity readings published in [61] and quantum yield data of the parent compound without active PET, DMA, published in [63]. (Reprinted in part with permission from [61]. Copyright 1988 American Chemical Society)...

In contrast to the -conjugated probe architecture utilizing an ICT process, the number of anion probes that rely on the fluorophore-spacer-receptor design and an active PET process is abundant [72], Again, anthracene and naphthalene... 

But the bulk of results have emerged from Shinkai s laboratories [178] in Fukuoka and Kurume, Japan. His prototypical example, 24, is essentially a classical aminomethylaromatic lumophore-spacer-receptor system with a twist that the weak B-N bond allows rather rapid PET from the amine unit to the anthracene resulting in weak fluorescence [176], The binding of glucose to produce the boronate ester leads to a much stronger B-N bond that arrests the PET process and produces a large fluorescence enhancement. 

A related anthracene-based ditopic sensor (11.28) has been constructed, which can recognise diammonium cations along the same lines as 3.103 (Section 3.12.3). Use of the anthracene-derived group as a spacer as in 11.27 gives fluorescent recognition of 11 N1 (Cl I NI I3+ guests as a function of spacer length.20... 

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