The composition of styrene/divinylbenzene/sorbitan monooleate/water emulsions has a dramatic effect on the openness of the cells of the foam prepared by polymerizing the monomers and subsequently removing the water. Monomer concentrations were varied from 0.025 to 0.20 g/cm3, while the surfactant level was varied from 1.2% to 320% of the monomer. Most remarkably, the variation in cell openness, and hence the continuity of the oil phase, was insensitive to the amount of oil. The variation was, however, strongly related to the surfactant-to-oil ratio. The structures of the resulting foams provide further evidence that emulsions possess considerable spatial ordering of the phases and, hence, the molecular species associated with them at the time of polymerization.

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Reaction of 2 or 3 equiv of potassium 1,3-bis(trimethylsilyl) with the triflate salts of Ce, Nd, Eu, Tb, and Yb gives the corresponding neutral bis-(Yb, Eu) and tris-(Ce, Nd, Tb) allyl lanthanide complexes in yields ranging from 40 to 80%. These complexes, which have been crystallographically characterized, initiate the polymerization of methyl methacrylate (MMA), but with poor turnover frequencies when compared with the corresponding salt complexes of the type K[LnA′ 3 ]. K[A′] itself initiates MMA polymerization, however, and its presence as an ion-pair in the salt complexes may contribute to the activity of heterometallic lanthanide catalysts.