Response Mechanism of 5, 10, 15, 20-tetraphenyl(porphyrinato) Manganase(III) chloride-Based Ion-Selective Membranes

망간포르피린을 함유한 고분자형 이온선택성 막전극의 감응 메카니즘

  • Received : 1996.07.01
  • Published : 1996.09.25

Abstract

Response mechanism for the chloride-selective membrane doped with 5, 10, 15, 20-tetraphenyl(porphyrinato)manganase(III) chloride(Mn(TPP)Cl) in PVC/DOS matrix is proposed by examining the visible spectra of the corresponding optode membrane. The visible spectra of Mn(TPP)Cl-doped membrane placed in aqueous solution show that the chloride ligand is easily replaced with water molecule. When other halogen ions, such as $F^-$, $Br^-$ and $I^-$, are added to the sample solution, they replace the water ligand, exhibiting distinctive change in the Soret band of Mn(TPP). On the other hand, bulky anions, such as SCN and salicylate, do not form a bond with the central metal. These results suggests that the potentiometric response of Mn(TPP)-based membrane results either from the ligand exchange (water with halides) at the central metal or from the counter ion exchange (chlorides with bulky lipophilic anions) around the positively charged porphyrin molecule in membrane phase. It was also noted that both hydration enthalpies of anions and their binding constants to Mn(TPP) play critical role in determining the potentiometric selectivity pattern of the membrane.

Keywords

Ion-selective electrode;phorphyrin;chloride;optode

Acknowledgement

Supported by : 과학재단, 교육부