3,3 - dibenzoic spacer

As multidentate ligands, s-tetrazines successfiilly find application in coordination chemistry. Their derivatives are useful building blocks for metal-organic frameworks (MOFs). Thus, the first example of an MOF with the novel 3,3 -(l,2,4,5-tetrazine-3,6-diyl)dibenzoic spacer 57 was reported and its luminescence and adsorption properties were studied (13IC546). Complexation of Sm(III) with 2,6-bis(4-npropyl-2,3,5,6-tetrazine-l-yl)pyridine 58 as an analog of BTP was studied using time-resolved laser fluorescence spectroscopy (13DT12139). 

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>. 

Derivative 178 containing a dibenzo-34-crown-10 ring interlocked with macrocycles incorporating two 4,4 -dipyr-idyl moieties tethered by different aryl spacers acts as bistable [2]catenane <20060L2119>. Variable-temperature (VT) NMR studies were used to determine the activation energy required for the conformational interconversions and to demonstrate that, by appropriate incorporation of bulky groups on one or both of the aryl linkers, it was possible to block one or both of the two circumrotation pathways. 

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. 

Compound 7, developed by Barboiu as a receptor for zwitterionic a-amino acids, contains a dibenzo 18-crown-6 unit as the receptor site for the ammonium group, while a simple primary ammonium group, separated from the crown subunit by a long aliphatic spacer, is the site for the interaction with the carboxylate group of the amino acid. According to the protonated nature of the ammonium group, the behavior of this receptor is pH sensitive and care needs to be taken to guarantee its full protonation at... 

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