Palladium(II) Complexes of 1‐Phosphaisoprene Molecules and Polymers: Reversible Cross‐Linking of a Phosphorus‐Containing Polymer

Abstract: The anionic polymerization of 1-phosphaisoprene [Mes*P=C(Me)−CH=CH2 (E-1)] affords poly(1-phosphaisoprene) 2 in high yield (75%). Concentrated solutions polymer (Mn = 21,800 g mol–1; Đ 1.02) a P-analogue natural rubber, undergo gelation upon treatment with [Pd(cod)Cl2] (0.15 P equiv). Evidence for P-coordination to PdII was obtained by 31P and 1H NMR spectroscopy. is reversed the addition PMe3 reformation recoverable along [PdII–PMe3 complexes were confirmed use labile metal-ligand bonds reversibly form gels unprecedented has relevance self-healing materials. In contrast, coordination [Pd(h3-C3H5)(μ-Cl)]2 well-defined complex 2·[Pd(h3-C3H5)Cl] which characterized 31P, 1H, 13C{1H} spectroscopy GPC. This chemistry complemented detailed molecular model studies monomer E-1 [Pd(h3-C3H5)(μ-Cl)]2].