Negative Ion Electrospray Ionization Mass Spectrum of Polyisobutenylsuccinic Anhydride:  Implications for Isobutylene Polymerization Mechanism

Harrison, Jayne E; Mijares, Cecilia M.; Cheng, Michael T.; Hudson, J.D.

doi:10.1021/ma011799h

Cited by 44 publications

(55 citation statements)

References 17 publications

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“…However, mass spectrometric analysis of highly nonpolar isobutylene with a fully saturated structure by MALDI and/or ESI fails due to the lack of appropriate ionization sites. It has also been shown that the introduction of aromatic moieties (e.g., using aromatic initiators for the isobutylene polymerization) and/or polar or readily ionizable groups into the polyisobutylene facilitates the ionization under MALDI and ESI conditions [12][13][14][15][16][17]. It is therefore evident that nonpolar polymers like polyisobutylenes are not amenable to MS analysis due to the lack of effective site for ionization.…”

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confidence: 99%

Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators

Nagy

Pálfi

Narmandakh

et al. 2009

J. Am. Soc. Mass Spectrom.

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Nine polyisobutylene (PIB) derivatives with different end groups (chlorine, vinyl, isobutenyl, 2,2-diphenylvinyl, and carboxyl) and molecular weights (1000 to 4500 g/mol), initiated by monofunctional and aromatic bifunctional initiators were studied by atmospheric pressure photoionization mass spectrometry (APPI-MS) in both negative and positive ion modes. Consistent with previous findings, negative ion APPI-MS revealed end-group identities through the formation of PIB adducts with chloride ions formed in situ from a chlorinated solvent (e.g., CCl 4 ) in the presence of a dopant (toluene). In positive ion mode, considerable fragmentation of these PIB derivatives was observed, rendering end-group determinations very difficult. The M n values obtained by APPI(Ϫ)-MS were considerably lower than those determined by SEC for PIB derivatives with M n higher than 2000 g/mol. PIBs containing carboxyl termini can undergo collision-induced dissociation, yielding structurally important product ions. The resulting APPI-MS/MS intensities were found to reflect the "arm-length" distribution for PIBs with bifunctional aromatic moieties. In positive ion mode, [M ϩ COCl]

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confidence: 99%

Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators

Nagy

Pálfi

Narmandakh

et al. 2009

J. Am. Soc. Mass Spectrom.

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“…Good spectral quality in the negative ion mode under MALDI conditions can also be attained by modifying the olefin end-groups of polyisobutylene to ϪSO 3 H [19]. Low molecular weight polyisobutylenes with succinic anhydride end-groups were analyzed by ESI in the negative ion mode [20]. In this case, the anhydride was hydrolyzed to a carboxylic acid end-group that is capable of forming a negative charge under ESI.…”

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confidence: 99%

Atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives

Kéki

Török

Nagy

et al. 2008

J. Am. Soc. Mass Spectrom.

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Atmospheric pressure photoionization mass spectrometric (APPI-MS) study on three types of polyisobutylene derivatives is reported. Two of the polyisobutylenes investigated were polyisobutylene with dihydroxy and diolefinic end-groups derived from aromatic moieties [dicumyl chloride, 1,4-bis(2-chloro-2-propyl)benzene], and the third contained no aromatic moieties with a monohydroxy end-group. All three polyisobutylene derivatives (PIBs) had an average molecular weight (M n ) of ϳ2000 g/mol, with a polydispersity lower than 1.2. In the positive ion APPI mode, protonated PIB molecules were formed, but the molecular weights obtained were considerably lower than those expected, indicating fragmentation of the PIB chains. In the negative APPI mode, using solvents such as tetrahydrofuran and toluene as dopants, no signal was obtained. However, in chlorinated solvents, such as CCl 4 , CHCl 3 , and CH 2 Cl 2 , in the presence of toluene dopant, PIB adducts with chloride ions were formed with relatively high signal intensity. In the case of CH 2 Cl 2 , no dopant (toluene) was necessary to generate chlorinated adduct ions, albeit increasing the toluene concentration in the flow increased the PIB signal intensity. The effect of the toluene concentration on PIB signal intensity was studied and models that include (1) photoionization of toluene, (2) formation of chloride ions from the chlorinated solvents by dissociative electron capture, (3) formation of chlorinated adduct ions and charge recombination reactions between the toluene radical cation, (4) chloride ions, and (5) olymer characterization, including the determination of molar mass, molar mass distribution, the mass of the repeat unit and end-groups, and functionality, is an important process that can be accomplished using several methods. Mass spectrometric methods, particularly those that utilize soft-ionization techniques, e.g., matrix-assisted laser desorption/ionization (MALDI) [1,2] or electrospray ionization (ESI) [3], are superior to other methods because they offer a unique capability to determine all of these parameters. Contrary to other spectroscopic methods, such as nuclear magnetic resonance (NMR), which can only determine an average value of some of the above parameters [e.g., the number-average molecular weight (M n ) and number average-functionality (F n )], mass spectrometric methods provide not only these average values, but the individual intact polymer molecules can also be detected. However, because soft-ionization is based on forming adduct ions with metal ions, e.g., alkali or silver ions or through protonation and/or deprotonation, mass spectrometric analysis of polymers having moieties that are unable to form ions presents difficulties. This is more pronounced as the polarity of the polymers decreases. For example, mass spectrometric analysis of polar polymers such as polyethylene glycol (PEG) and polypropylene glycol (PPG) can easily be achieved using . Nonpolar polymers such as polystyrenes are also amenable to MALDI and ESI through the f...

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“…To overcome such bottlenecks, two synthesis routes are widely used: the making of amphiphilic block copolymers, amphiphilic micelles and vesicles and/or the telechelic modification of the polymer . Indeed, PIBs can be terminally and/or centrally functionalized exhibiting aromatic moieties such as central phenyl group and/or polar moieties such as hydroxyl groups with or without additional terminal phenyl groups, epoxides, carboxyl, bis(imidazole‐1‐carboxylate) esters, secondary or tertiary amine, amide, sulfonated, succinic anhydride, functionalized thymine, or glucopyranoside …”

Section: Introductionmentioning

confidence: 99%

Harnessing Polyisobutylene by Rotaxanation with γ‐Cyclodextrin: Opportunities for Making Smart Molecular Necklaces

Przybylski

Ramoul

Bonnet

et al. 2019

Macro Chemistry & Physics

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A new type of polyrotaxane based on the threading of γ‐cyclodextrins (γ‐CDs) along a highly hydrophobic polymer, polyisobutylene (PIB), is successfully prepared and finely characterized. The used radical coupling associated with tuned reaction time and temperature leads to a fast and controlled necklace synthesis with low reagent consumption. Synthesis exhibits appealing conversion and threading rates with almost 100% and 62–73%, respectively. A combination of well‐established SEC and NMR techniques, with a more forefront MALDI‐TOF MS approach, provides details on the original PIB and the resulting polyrotaxanes (M w, M n, PDI, and average number of γ‐CD threaded). Interestingly, tetramethylguanidinium‐2‐(4‐hydroxyphenylazo)benzoate in DMF for MALDI analysis is revealed as a suitable matrix to overcome solubility troubles widely observed with PIB. Moreover, rotaxanation appears as an alternative to the grafting of polar groups to modify/handle hydrophobic polymers. Such an approach offers new opportunities to achieve the synthesis, with unambiguous evidence, of new supramolecular necklaces based on highly hydrophobic polymers.

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Negative Ion Electrospray Ionization Mass Spectrum of Polyisobutenylsuccinic Anhydride: Implications for Isobutylene Polymerization Mechanism

Cited by 44 publications

References 17 publications

Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators

Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators

Atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives

Harnessing Polyisobutylene by Rotaxanation with γ‐Cyclodextrin: Opportunities for Making Smart Molecular Necklaces

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