The synthesis and aggregation studies of a pair of 3, 4,12,13,21,22,30,31- octasubstituted 2,3-Naphthalocyanine (Ncs) 1 and 2 was reported. The synthetic route leading to these naphthalonitriles started from dimethyl 4,5-dihydroxyphthalate onto which the previously synthesized dendritic alcohols 3 and 4 were introduced through the Mitsunobu protocol. The obtained diesters 6 and 7 were reduced to the corresponding 1,2-dimethanols (8 and 9), and subsequent Swern oxidation provided the disubstituted dendritic phthalaldehydes 10 and 11. Finally, 10 and 11 were converted to naphthalonitriles 12 and 13 through base-promoted condensation with succinonitrile in DMSO. Compounds 1 and 2 were purified by flash column chromatography. Initial molecular aggregation studies were performed in solution as a function of increasing volume fraction of EtOH. The B-bands at 332 and 402 nm exhibited only slight hypochromicity during this change in solvent conditions.
Tapered dendritic structures with a crown ether receptor moiety and a hydrophobic dendritic sector linked through an azobenzene were prepared and characterized. The dendritic structures exhibit typical azobenzene photoresponsive behavior in solution.
Statistical condensation of norbornenyl-tagged phthalonitrile 3 (Pn A) and 4,5-di-4-methoxyphenoxyphthalonitrile 4 (Pn B) followed by ring-opening metathesis polymerization (ROMP) of Pcs AB(3) and B(4) produced asymmetric Pc-appended polymers. Acidic cleavage of the resulting polymers afforded 2,3,9,10,16,17-hexa-(4-methoxyphenoxy)-23-hydroxy Pc 9. A more soluble 2,3,9,10,16,17-hexa-4-pentylphenoxy-23-hydroxy Pc 13 was synthesized by the same strategy and modified with sebacoyl chloride demonstrating that the unmasked hydroxyl site is reactive as a nucleophile.
We prepared a rigid, chiral polymer (1) from optically active hydrobenzoin-based subunits. Nonracemic monomer units 6 and 8 were prepared by asymmetric dihydroxylation (AD) methodology and polymerization was carried out under Sonagashira coupling conditions. Polymer I was obtained in good yield with a molecular weight Mn = 5,100 (PDI = 2.3). Modeling suggests that polymer 1 could form a stable helical mainchain conformation in solution or the solid state. The chiroptical data of the polymer and a low-molecular weight model compound (9) are compared. © 2002 Wiley-Liss, Inc.
Olefin isomerization of allylic ethers and alcohols is catalyzed by RuII(H2O)6(tos)2 (tos = p-toluenesulfonate) (1) under mild conditions in aqueous solution to yield the corresponding carbonyl compounds. Non-allylic olefins are also isomerized, although homoallylic alcohols exhibit stability toward isomerization. An exclusive 1,3-hydrogen shift is observed in the isomerization of allyl-1,1-d2 alcohol to propionaldehyde-1,3-d2 and allyl-1,1-d2 methyl ether to 1-propenyl-1,3-d2 methyl ether by 1 in aqueous solution. The presence of crossover products from the isomerizations of mixtures of (a) allyl-3-13C alcohol and allyl-1,1-d2 alcohol and (b) allyl-1,1-d2 methyl ether and allyl ethyl ether demonstrates that the isomerization of both alcohols and ethers occurs via intermolecular hydrogen shifts. A modified metal hydride addition-elimination mechanism involving exclusive Markovnikov addition to the double bond directed by the oxygen functionality of the substrate has been proposed. © 1994 American Chemical Society.