Towards Advances in Molecular Understanding of Boric Acid Biocatalyzed Ring-Opening (Co)Polymerization of δ-Valerolactone in the Presence of Ethylene Glycol as an Initiator

Abstract

Following our previous studies on the molecular level structure of (co)oligoesters obtained via anionic homo- and co-polymerization of novel β-substituted β-lactones, prepared by the atmospheric pressure carbonylation reaction of respective epoxides, the boric acid biocatalyzed ring-opening (co)polymerization of δ-valerolactone has been studied. As a co-monomer the 6-methy-ε-caprolactone, prepared by the one-pot oxidation of respective alcohol, and ethylene glycol as polymerization initiator were used. The obtained copolymers were characterized by 1H-NMR, GPC and ESI-MS, respectively in order to confirm their chemical structures and identity. Subsequently, tandem mass spectrometry (MS-MS studies) via collision-induced dissociation were utilized to characterize the fragmentation pattern. ESI-MS and NMR analyses confirmed the formation of random linear copolymer chains composed of different polyester repeat units. MS-MS experiments showed that fragmentation proceeds via ester bound cleavage along the (co)polyester chains. The innovative aspect of this contribution is related to the elaboration of the telechelic (co)polymers end-capped with hydroxyl end groups and well-defined molecular architectures, which could facilitate the development of new flexible macromolecular systems for potential biomedical applications.

Matrix-Assisted Laser Desorption and Electrospray Ionization Tandem Mass Spectrometry of Microbial and Synthetic Biodegradable Polymers

“…ESI tandem MS has been used more extensively than MALDI-MS/MS in the analysis of biodegradable polymers. In the literature, ESI-MS/MS studies concern fragmentation analysis and insights on comparative dissociation tools [ 50 , 51 , 53 , 55 , 82 ], structural characterization [ 19 , 55 , 63 , 64 , 65 , 67 , 68 , 70 , 71 , 72 , 74 , 75 , 80 , 81 , 83 , 86 , 121 , 122 , 123 , 124 , 125 , 126 ], drug delivery systems [ 89 , 90 , 91 , 95 , 96 , 97 , 98 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 ] and degradation studies [ 111 , 112 , 113 , 114 , 115 , …”

“…Random breakage of ester bonds along the polyester chain was observed as well, with the formation of 2-hydroxyethylpentene-4-enoate (144 Da) and the loss of 2-hydroxyethyl 5-methylhex-5-enoate (172 Da). Moreover, additional fragments of neutral ions were found at m / z 841, 741, 641, 541, and 441 in the same series ( Scheme 3 ) [ 55 ].…”

“…Numerous studies have been focused on the ESI-MS/MS analysis of polyhydroxyalkanoates (PHA), a family of biodegradable and biocompatible polymers produced by some strains of bacteria in certain conditions [ 55 , 70 , 71 , 72 , 74 , 75 , 81 , 83 , 121 ]. Kowalczuk and Adamus carried out numerous investigations and reviewed the literature on MS and MS/MS procedures for the elucidation of the structure of microbial PHA, their synthetic analogs and degradation products [ 15 ].…”

“…In the literature, several papers have been published about the ESI-MS/MS analysis of biodegradable copolymers [ 51 , 53 , 55 , 57 , 58 , 61 , 69 , 71 , 72 , 74 , 77 , 81 , 121 , 126 ], compared to the limited number of publications on MALDI-MS/MS. Again, CID has been the mainly used fragmentation technique [ 59 , 62 , 77 , 83 ] ( Table 1 ).…”

“…In the last decades, studies on fragmentation mechanisms [ 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ], structure and architecture [ 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 ], biopharmaceutical and drug delivery systems (DDS) [ 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , …”