Synthesis and characterization of the heteroleptic dipyrrinato complexes [Cu2(2-pcdpm)2(acac)2] (1), [Cu 2(2-pcdpm)2(hfacac)2] (2), [Cu 3(4-OHdpm)2(acac)4] (3), [Cu 3(4-OHdpm)2(hfacac)4] (4), [Cu 2(3-OHdpm)(acac)3] (5), [Cu2(3-OHdpm)(hfacac) 3] (6), [Cu(2-OHdpm)(acac)] (7) and [Cu(2-OHdpm)(hfacac)] (8) (acac = acetylacetone; hfacac = hexafluoroacetylacetone; 2-pcdpm = 4-(2-methoxypyridyl) phenyldipyrromethene; 3-pcdpm = 4-(3-methoxypyridyl)phenyldipyrromethene; 4-pcdpm = 4-(4-methoxypyridyl)phenyldipyrromethene; 4-/3-/2-OHdpm = 4-/3-/(2-hydroxyphenyl)dipyrromethene) have been described. The complexes 1-8 have been characterized by elemental analyses, ESI-MS, IR, UV-Vis, EPR and electrochemical (CV and DPV) studies. Electronic absorption spectra of 1-8 clearly suggested that position of the absorption bands depend on the nuclearity and coordination geometry about the copper(II) centres. Structures of 1, 2, 3 and 7 have been determined by X-ray single crystal analyses. The spectral and structural studies revealed that copper(II) in 1 and 2 adopted square pyramidal geometry, whereas in 7 a square planar geometry. On the other hand in trinuclear complex 3 one copper(II) adopted square planar, while other two square pyramidal geometry. In their cyclic voltammograms, 1-6 exhibited an irreversible oxidation and two reduction waves whereas 7 and 8 displayed one oxidation and reduction wave. Variable temperature magnetic susceptibility measurements suggested paramagnetic nature of the complexes 1-3. The X-ray photoelectron spectroscopic (XPS) studies indicated that copper(II) centres in complex 3 are present in two different coordination environments. Room temperature EPR studies on 1-8 (g|| > g∥ > 2.003) suggested a typical d9 copper(II) with unpaired electron lying in a d x2-y2 orbital.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry