A total of 202 organic solvents and the gas phase were placed on a solvent basicity scale for hydrogen bond acceptor based on parameter SB. The value of such a parameter can readily be determined from the UV/Vis spectrum for an appropriate acid probe (5‐nitroindoline) (NI) and its non‐acid homomorph (1‐methyl‐5‐nitroindoline) (MNI). The proposed scale can advantageously substitute the more widely used solvent scales such as Gutmann's donor number (DN), the Koppel‐Palm B(MeOD) scale, and the Taft‐Kamlet β scale. While data for the proposed scale are derived only from electronic transitions, they are accurately descriptive of solvent basicity in both spectroscopy (UV/Vis, IR and NMR) and miscellaneous chemical areas (thermodynamic, kinetics, and electrochemistry).

The synthesis and spectroscopic characterization of nanometer-sized conjugated molecules of 5-X-naphthylethynyl (X= NO(2), NMe(2)) units with precise length and constitution have been carried out. A new extended pi-conjugated 5-nitronaphthyl family was synthesized by palladium-catalyzed cross-coupling reaction between the protected 5-iodonaphthylethynyl 5a and 1-ethynyl-5-nitronaphthalene 9, or the resulting ethynyl compound 11 and the 1-iodo-5-nitronaphthalene 3. Catalytic oxidative dimerization of the terminal acetylene compounds permits the isolation of the corresponding 1,3-butadiyne derivatives 16-18, with the nitro groups at the ends of the conjugation, in excellent yields. A new family of conjugated 5-nitro-(naphthylethynyl)-[5-(N,N-dimethylamino)]naphthalene (20-22), was also synthesized by palladium-catalyzed cross-coupling reaction between 5-iodo-N,N-dimethylnaphthalene-1-amine (19) with the appropriate terminal acetylene (9, 11, and13 respectively). Compounds 20-22 show a fluorescence emission and also exhibit a charge-transfer absorption in the visible spectrum. X-ray structure of 20 confirms a centrosymmetric dimer association with an interplanar distance of 3.43 A, and the naphthalene rings adopt an anti conformation around the Ctbd1;C triple bond.

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Nanometer-sized conjugated 1,4- and 1,3,5-ethynylphenyl oligomers were synthesized starting from 3,5-di(trimethylsilylethynyl)phenylacetylene and p-[3,5-di(trimethylsilylethynyl)-1-ethynylphenyl]phenyl acetylene by cross-coupling reaction with a convenient haloaryl derivative, catalyzed by palladium(II)/copper(I), in excellent yield. The terminal acetylenes were efficiently prepared by a specific protection-deprotection methodology. All ethynylphenyl homologues obtained show fluorescence emission, with the bathochromic shift of approximately 20 nm by each ethynylphenyl unit increasing the conjugate chain. Parallel conjugated ethynylphenyl chains were prepared through the insertion of a 1,5-naphthalene subunit, and the compounds exhibit fluorescence radiation emission.

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