New insights into 1,2,4-trioxolane stability and the crucial role of ozone in promoting polymer degradation.

نویسندگان

  • Richmond Lee
  • Michelle L Coote
چکیده

Quantum chemical calculations reveal that ozone is capable of instigating a series of degradative processes in poly(methyl methacrylate). The crux lies in the self-decomposition of 1,2,4-trioxolane, which undergoes a spin intersystem crossing process and O-O bond cleavage to unravel a triplet biradical intermediate that facilitates auto-degradation of the polymer chain.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Peroxide bond strength of antimalarial drugs containing an endoperoxide cycle. Relation with biological activity.

Several endoperoxide compounds are very efficient antimalarial analogues of the natural drug artemisinin. Quantum chemical calculations have been used to correlate the computed free energies of the O-O bond with respect to the total number of oxygen atoms contained in the cycle, and with the size/strain of the cycle (5- or 6-membered cycles). The gas-phase homolysis of the O-O bond has been stu...

متن کامل

Evaluation of effects of thymolphthalein on thermooxidative stability of polypropylene

The present work is aimed to find a new and efficient type of antioxidants for polypropylene. Hence, effects of 3,3-bis(4-hydroxy-2-methyl-5-propan-2-ylphenyl)-2-benzofuran-1-one, generally known as thymolphthalein, on thermo-oxidative stability of polypropylene in solid and melt states were evaluated and compared with those of SONGNOX 1010, an efficient commercially used antioxidant for the po...

متن کامل

Ozonized vegetable oils and therapeutic properties: A review

Ozonized oils represent an interesting pharmaceutical approach to the management of a variety of dermatological pathologies. Ozone reacts with carbon-carbon double bonds of unsaturated fatty acids according to the mechanism described by Criegee, forming ozonides or 1,2,4 trioxolane rings and peroxides as the most important products, responsible for the antimicrobial activity and stimulating tis...

متن کامل

Endoperoxide antimalarials: development, structural diversity and pharmacodynamic aspects with reference to 1,2,4-trioxane-based structural scaffold

Malaria disease continues to be a major health problem worldwide due to the emergence of multidrug-resistant strains of Plasmodium falciparum. In recent days, artemisinin (ART)-based drugs and combination therapies remain the drugs of choice for resistant P. falciparum malaria. However, resistance to ART-based drugs has begun to appear in some parts of the world. Endoperoxide compounds (natural...

متن کامل

Relationship between antimalarial activity and heme alkylation for spiro- and dispiro-1,2,4-trioxolane antimalarials.

The reaction of spiro- and dispiro-1,2,4-trioxolane antimalarials with heme has been investigated to provide further insight into the mechanism of action for this important class of antimalarials. A series of trioxolanes with various antimalarial potencies was found to be unreactive in the presence of Fe(III) hemin, but all were rapidly degraded by reduced Fe(II) heme. The major reaction produc...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Physical chemistry chemical physics : PCCP

دوره 15 39  شماره 

صفحات  -

تاریخ انتشار 2013