Spacers naphthalene

Systems with two 2-hexylthieno[3,2-6]thiophenes connected via a ji-conjugated spacer, naphthalene or anthracene, were built up via conversion of 78 into the 1,3,2-dioxaborolane 79 then Suzuki cross-coupling of this with 2,6-dibromonaphthalene or 2,6-dibromoanthracene (Scheme 19) [40]. 

Okayama, Japan. The synthetic procedures for S-D dyads and their reference compounds shown in Fig. 6 are illustrated in Fig. 7, where a naphthalene and a ferrocene moiety are used as an S and a D moiety, respectively. For comparison of photoinduced electron transfer rates between a single alkyl chain and a triple alkyl chain as the spacers of the S-D dyads with the same length of four-carbons, S-D dyads with a rigid spacer with a bicyclo[2.2.2]octane were synthesized [39]. The synthetic procedure for the S-D dyads with the rigid spacer is also shown in Fig. 8 [39], Other amphiphilic compounds and chemicals were commercially available. 

Stable monolayers of S-D amphiphilic dyads with a single alkyl chain spacer containing a naphthalene and a ferrocene moiety... 

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... 

Shibata further examined consecutive reactions of poly-ynes. When tetraynes (where two 1,6-diyne moieties were connected with a naphthalene spacer) were submitted, quinquearyl compounds with four consecutive axial chiralities were obtained (Scheme 11.15). Even an octayne proved to be a good substrate, and a noviaryl compound with eight consecutive axial chiralities was obtained in almost perfect enantioselectivity (Scheme 11.16) [23]. 

An aromatically stabilized carbodication, 37, was prepared by Komatsu and coworkers in strongly acidic media. The ion undergoes deprotonation to give a conjugated monocation, 38, in less acidic media. The corresponding distonic carbodications with 1,4-phenylene, 1,5-naphthalene, and 1,8-naphthalene spacer groups (39, 40, and 41) have been prepared and well characterized. ... 

With the aim of binding dicarboxylic anions, Schmidtchen and coworkers synthesized receptor 16 by means of connecting two bicycloguanidinium building blocks with a naphthalene spacer [23]. Due to its flexible framework it binds dianions that range in size from carbonate up to p-phenylenbis(3-acrylate) with maximum association for malonate and 3-nitroisophthalate (K ss = 16500 M S 14500 M S respectively, in methanol) [24],... 

The fluorescence is measured in dilute solution and in glassy PMMA for polyesters in which 2,6-naphthalene dicarboxylate is the rigid unit, and (CF iy+t is the flexible spacer. The anisotropy in the rigid medium demonstrates the existence of intramolecular energy migration, which becomes more important as y decreases from 5 to 1. The Forster radius is about 12 A in the bichromophoric compounds and 14 A in the polyesters. 

Fluorescence is measured in dilute solution of model compounds for polymers of 2,6-naphthalene dicarboxylic acid and eight different glycols. The ratio of excimer to monomer emission depends on the glycol used. Studies as functions of temperature and solvent show that, in contrast with the analogous polyesters in which the naphthalene moiety is replaced with a benzene ring, there can be a substantial dynamic component to the excimer emission. Extrapolation to media of infinite viscosity shows that in the absence of rotational isomerism during the lifetime of the singlet excited state, there is an odd-even effect In the series in which the flexible spacers differ in the number of methylene units, but not in the series in which the flexible spacers differ in the number of oxyethylene units. 

The work of Thomas et al. was preceded by the formation of a range of related molecular squares and triangles such as Fujita s molecular square (10.10), which is able to function as a solution host for aromatic guests such as naphthalene with a binding constant, Ku of 1800 M 1. Rigid spacers (edges)... 

PEN is more rigid than PETE because naphthalene groups, which are larger than the phenyl groups present in PETE, serve as spacers between ethylene glycol-derived units. 

Copolymers containing alternating l,4-bis(phenylethenyl)benzene, l,4-bis(phenylethenyl)-2,5-dimethoxybenzene or l,5-bis(phenylethenyl)naphthalene chromophores, and dibenzo-24-crown-8 spacers within the polymer backbone, best represented by 87, showed blue light emission in solution, and tunable photoluminescence and electroluminescence depending on the structure of the chromophore. Blends of these copolymers with a small amount of poly(ethylene oxide), and lithium salt as active layers, form efficient light-emitting electrochemical cells <2003JMC800>. 

A longer spacer group has also been inserted in the templating molecule by exchanging the 2,6-disubstituted naphthalene spacer of 38 for a 4,4 -biphenyldiyl... 

Electron transfer was followed by the exciplex fluorescence method LE and exciplex-type emissions were recorded as a function of internal energy, as in the previously cited papers (Section 4.2). Here, however, the initial excitation was either of the electron donor or the acceptor. The electron-donating power was varied by simple substitution, with minimal interference with the nature of the spacer. Typical donors were para-substituted anilines or substituted naphthalenes. Typical acceptors were cyano-substituted naphthalenes (when anilines served as the donors) and dicyanoethylene or dicarbomethoxyethylene when naphthalenes served as donors. Spacers were of varying flexibility semi-flexible (a piperidine ring which may have a... 

The extended dibenzo-TTF derivative 958 containing a naphthalene-1,8-diyl spacer was obtained from the corresponding diketone 956 by Horner-Wittig reaction with the anion derived from the phosphonate 957 (Equation 106) <2000J(P1)3417>. Under similar conditions, the isomeric rt-exTTFs with naphthalene-2,3- and -1,2-diyl units were also prepared. 

Novel 2 -modified nucleoside triphosphate derivatives incorporating imidazole, amino or carboxylate pendant groups attached to the 5-position of pyrimidine base through alkynyl and alkyl spacers (115) have been synthesised. In one reported procedure, the appropriately protected modified nucleoside was phosphorylated with POCI3 in triethylphosphate in the presence of 1,8-bis(dimethylamino)naphthalene. The phosphorochloridate intermediate was then condensed in situ with tri-n-butylammonium pyrophosphate to yield the protected triphosphate analogue that was then deprotected. In another... 

From the systematic investigation of the Park and Jew group, several highly efficient and practical polymeric cinchona PTCs were developed (Scheme 6.6). Interestingly, polymeric catalysts with a specific direction of attachment between aromatic linkers (e.g., benzene or naphthalene) and each cinchona unit were found to be effective in the asymmetric alkylation of 4b. The phenyl-based polymeric PTCs with the meta-relationship between cinchona units such as 14, 15, and 18 showed their high catalytic efficiencies. Furthermore, the 2,7-dimethylnaphthalene moiety as in 16 and 17 was ultimately found to be the ideal spacer for dimeric cinchona PTC for this asymmetric alkylation. For example, with 5 mol% of 16, the benzylation of 4b was completed within a short reaction time of 30 min at 0 ° C, affording (S)-5a in 95% yield with 97% ee. Almost optically pure (>99% ee) (S)-5a was obtained at lower reaction temperature (—40 °C) with 16, and moreover, even with a smaller quantity (1 mol%), its high catalytic efficiency in terms of both reactivity and enantioselectivity was well conserved. 

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