Novel N2O2 tetradentate ligands, H-3BPD and H-2BPD were synthesized. Hydrochloric acid salts of Br-3BPD, Cl-3BPD, Br-2BPD and Cl-2BPD having Br and Cl substituents at the para position of the phenol hydroxyl group, were synthesized. The ligands were characterized by C. H. N atomic analysis, 1H NMR, 13C NMR, UV-visible, and mass spectra. The proton dissociation constants (logKn H) of the phenol hydroxyl group and secondary amine of the synthesized N2O2 ligands were shown by four step wise values. The orders of the calculated overall proton dissociation constants (logβp) were Br-3BPD < Cl-3BPD < H-3BPD in case of 3BPD and Br-2BPD < Cl-2BPD < H-2BPD in case of 2BPD respectively. The order agreed well with that of para Hammett substituent constants(δp). The stability constants(logKML) of the complexes between the synthesized ligands and transition metal(II) ions agreed with the order of logβp of the ligands. The order of the logKML value of the each transition metal (II) ion was Co(Ⅱ) < Ni(Ⅱ) < Cu(Ⅱ) > Zn(Ⅱ) > Cd(Ⅱ) > Pb(Ⅱ), which agreed well with that of Iriving-Williams series.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 시약 및 기기
  2.2. 리간드 합성
  2.3. 리간드의 양성자 단계해리상수 결정
  2.4. 중금속(Ⅱ) 이온과의 안정도 상수 결정
 3. 결과 및 고찰
  3.1. 질소-산소 계 네 자리 리간드의 합성
  3.2. 전위차 적정법에 의한 리간드의 양성자 해리상수 결정
  3.3. 전위차 적정법에 의한 리간드와 전이금속과의 착화합물 안정도상수 결정
 4. 결 론
 참 고 문 헌

• 김선덕(대구대학교 화학․응용화학과) | Sun-Deuk Kim (Department of Chemistry and Applied Chemistry, Daegu University) Corresponding author
• 설종민(대구대학교 화학․응용화학과) | Jong-Min Seol (Department of Chemistry and Applied Chemistry, Daegu University)