Ring‐opening polymerization of ε‐caprolactone with a divalent samarium bis(phosphido) complex

Abstract

ABSTRACT:The ring-opening polymerization of -caprolactone initiated with a divalent samarium bis(phosphido) complex [Sm(PPh 2 ) 2 ] is reported. The polymerization proceeded under mild reaction conditions and resulted in polyesters with number-average molecular weights of 8.2 ϫ 10 3 to 12.5 ϫ 10 3 . The yield and molecular weight of poly(-caprolactone)s were dependent on the experimental parameters, such as the monomer/initiator molar ratio, the monomer concentration, the reaction temperature, and the polymerization time. The obtained polymers were characterized with Fourier transform infrared, NMR, gel permeation chromatography, and differential scanning calorimetry. On the basis of an end-group analysis of low-molecular-weight polymers by NMR spectroscopy, a coordination-insertion mechanism is proposed for the polymerization.

Ring‐opening polymerization of 1,4‐dioxan‐2‐one initiated by lanthanum isopropoxide in bulk

“…In addition, some trivalent rare earth compounds show very low toxicity 4, 46. Recently, Shen and coworkers have successfully developed several rare earth coordinate initiators47, 48 and single‐component rare earth initiators46, 49–54 for ROP of lactones and lactides. Feijen and coworkers55 reported a highly efficient initiator system for the preparation of polyesters using lanthanide tris(2,6‐ di ‐ tert ‐butylphenolate)s and various alcohols, and it exhibited excellent controllability over molecular weight and end‐group identity.…”

Octa-armed star-shaped poly(ε-caprolactone)s with a phthalocyanine core by ring-opening polymerization: Synthesis and characterization

“…Owing to the compact spherical structure of star and branched polymers, GPC measurements usually underestimate their actual molecular weights since these instruments are calibrated with linear polymers, and it is reasonable to say that quantitative 1 H-NMR analysis is more accurate than GPC for calculating the molecular weight in the ROP of PCL [11,12]. [64,65]. The intrinsic viscosities of the prepared polymers were 0.09, 0.109 and 0.112 dL/g for 5, 6 and 7, respectively.…”

“…THF was used as eluent with the correction formula: M n,PCL = 0.259 × M n,GPC 1.073 [63]. f M n;v denotes the average viscosity molecular weight of the polymer measured at room temperature in DMF and calculated from: [η ]= 1.94 ×10 −4 M vis 0.73 [64,65]. Table 3 Thermal properties of the 8SPCL (5−7) polymers.…”

Synthesis and characterization of Metal-mercaptoacetate hybrids and its application towards ring opening polymerization of ε-caprolactone: A comparative study

“…Recently, metal salts and their complexes are employed as an initiator cum catalyst for the ROP of cyclic esters. Metal-alkoxide complex [18], Mn(II)-asymmetric SB complex [19], Mn-salen complex [20], Co complex [21], Mo complex [22], Mn-oxydianiline complex [23], Zn complex [24], Al-salicylaldimine complex [25], V complex [26], Al-phenolate complex [27], Zn complex [28], Ru complex [29], Zn-phenoxyimine complexes [30], Ti complex [31] and Sm complex [32] were employed for the ROP of CL. Among the metal complexes, Mn and Mo complexes were considered in the present research work due to the following reasons.…”