Organometallic Strontium Borohydrides: Synthesis, X-ray Structures, Catalytic Polymerization of ε-Caprolactone, and Density Functional Calculations

The first organometallic strontium–borohydride complexes [(η5‐C5Me5)Sr(BH4)(thf)2]2 (see structure), [{(Me3SiNPPh2)2CH}Sr(BH4)(thf)2], and [Sr(BH4)2(thf)2] have been isolated. Polyesters with the highest molar mass prepared from a molecular alkaline earth metal were obtained from these complexes in the controlled ring‐opening polymerization of ε‐caprolactone (PCL). α,ω‐Dihydroxytelechelic PCLs were obtained, in agreement with density functional calculations.