The polymerization of a series of diacetylene Langmuir monolayers modified in the hydrophobic as well as in the hydrophilic part of the molecule was studied by measuring the kinetic changes of the mean molecular area and UV-vis spectra. The polymerization properties of the monolayers were dependent on the position of the diacetylenic unit and whether an ester or sulfonyl group was introduced in the hydrocarbon chain. The substances containing a sulfonyl group showed the highest polymerization activity. The blueto-red transition usually observed for diacetylenes in Langmuir and Langmuir-Blodgett films due to UV irradiation was not observed, instead the studied substances formed directly a red form polydiacetylene. A first-order consecutive reaction kinetic model with a steady-state approximation was successfully adapted to the experimental results of three of the studied compounds.

Reactions of [H2Os3(CO)10] with a series of diynes, RC2C2R‘ (1:  R = Ph, R‘ = CH2OH; 2:  R = Ph, R‘ = C(O)Ph; 3:  R = R‘ = C(OH)Me2), have been studied. It was found that upon coordination to the triosmium cluster, the nucleophilic oxygens of the R‘ substituents of 1 and 2 take part in intramolecular cyclization reactions to give [HOs3(CO)10{μ-η1:η2-PhCH2(CCH−CCH−O)}] (5) and [HOs3(CO)10{μ-η1:η1-Ph(CCH−CC−O)CPh}] (6), respectively, both of which contain furan rings coordinated to the cluster core. On heating of the latter compound, the furan moiety remains intact, but a carbonyl group dissociates from the cluster, leading to the formation of [HOs3(CO)9(μ3-η1:η3:η1-Ph(CCH−CC−O)CPh)] (7) with a closed “C3Os3” pentagonal pyramidal structure. Reaction of [H2Os3(CO)10] with 3 does not lead to cyclization of the diyne; instead, the clusters [Os3(CO)10{μ3-η2-(RCHCH−C2R)}] (8) and [Os3(CO)10{μ3-η2-(RC2C2R)}] (9) are formed. Deuterium labeling of the starting compounds has been used in the reaction of [H2Os3(CO)10] with HOCH2C2C2CH2OH in order to investigate possible mechanisms of the cyclization reaction. The crystal and molecular structures of clusters 5, 7, and 9 are presented.

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