Département de chimie moléculaire

The five-coordinate mono-halide mononuclear Zn(II) complexes [Zn(tpa)X]+ (tpa = tris(2-pyridylmethyl)amine; X = I ([Zn(tpa)I]I; 1a), Br ([Zn(tpa)Br](ZnBr4)0.5; 2a) and Cl ([Zn(tpa)Cl](ZnCl4)0.5; 3a)) and the six-coordinate mononuclear complex [Zn(tpa)(NCS)2] (4a) were synthesized and characterized by x-ray crystallog. The [Zn(tpa)X]+ complexes doped with the corresponding [Mn(tpa)X2] complexes (X = I (1b), Br (2b) and Cl (3b)) were synthesized and their electronic properties studied by multi-frequency high field EPR (HF-EPR) (95-285 GHz). The magnetically dild. conditions allow the detn. of the hyperfine coupling const. A (|A| = 68 × 10-4 cm-1 for 1b-3b). The zero-field splitting parameters (D and E) found for 1b-3b are comparable to those found for neat samples of the [Mn(tpa)X2] complexes (1b: |D| = 0.635 cm-1, |E/D| = 0.189; 2b: |D| = 0.360 cm-1, |E/D| = 0.192; 3b: |D| = 0.115 cm-1, |E/D| = 0.200). The efficacy of using multi-frequency EPR under dil. conditions to precisely det. spin Hamiltonian parameters is discussed. [on SciFinder(R)]