The anionic polymerization of 1-phosphaisoprene [Mes*P=C-(Me)À CH=CH 2 (E-1)] affords poly(1-phosphaisoprene) 2 in high yield (75 %). Concentrated solutions of polymer 2 (M n = 21,800 g mol À 1 ; Đ = 1.02) a P-analogue of natural rubber, undergo gelation upon treatment with [Pd(cod)Cl 2 ] (0.15 P equiv). Evidence for P-coordination of 2 to Pd II was obtained by 31 P and 1 H NMR spectroscopy. The gelation is reversed by the addition of PMe 3 and the reformation of recoverable 2 along with [Pd II À PMe 3 ] complexes were confirmed by 31 P NMR spectro-scopy. The use of labile metal-ligand bonds to reversibly form gels is unprecedented and has relevance to self-healing materials. In contrast, coordination of 2 to [Pd(η 3 -C 3 H 5 )(μ-Cl)] 2 affords the well-defined complex 2 • [Pd(η 3 -C 3 H 5 )Cl] which was characterized by 31 P, 1 H, 13 C{ 1 H} NMR spectroscopy and GPC. This polymer chemistry was complemented by detailed molecular model studies of the coordination chemistry of monomer 1-phosphaisoprene E-1 with [Pd(cod)Cl 2 ] and [Pd(η 3 -C 3 H 5 )(μ-Cl)] 2 ].
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.