Premium
Transition Metal Coordination Compounds of Bisamidobispyridyl Ligands
Author(s) -
Comba Peter,
Goll Wolfgang,
Nuber Bernhard,
Várnagy Katalin
Publication year - 1998
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199812)1998:12<2041::aid-ejic2041>3.0.co;2-s
Subject(s) - chemistry , transition metal , coordination complex , nanotechnology , combinatorial chemistry , metal , organic chemistry , catalysis , materials science
The syntheses of N , N ′‐bis‐[(2‐pyridylmethyl)]‐1,3‐diamidopropane (papH 2 ) and N , N ′‐bis‐[(2‐pyridylmethyl)]‐1,3‐diamido‐2‐hexadecylpropane (C 16 papH 2 ) are reported together with the results of potentiometric titrations of papH 2 with Co(II), Ni(II), Cu(II) and Zn(II), spectroscopic and electrochemical data of [Ni(pap)] and [Cu(pap)], structural studies involving the X‐ray analyses of the metal‐free papH 2 ligand and the corresponding Ni(II) and Cu(II) complexes [Ni(pap)] × 2 H 2 O and [Cu(pap)] × 3 H 2 O, and force‐field calculations (MM) of [Co(pap)], [Ni(pap)], [Cu(pap)] and [Zn(pap)] and the corresponding complexes of the ligand with ortho ‐methyl‐substituted pyridyl groups (Me 2 papH 2 ); the results of metal ion transport [Co(II), Ni(II), Cu(II) and Fe(II)] from aqueous solutions through C 16 papH 2 containing dichloromethane phases are also given. The extractability with C 16 papH 2 increases along the series Fe(II) < Co(II) < Ni(II) < Cu(II), and this is confirmed by the potentiometric data (papH 2 , aqueous solutions; logβ ML [Co(II)] = 1.75; logβ MLH–2 [Ni(II)] = –11.49; logβ ML [Cu(II)] = 3.41; logβ MLH–2 [Cu(II)] = –4.491;logβ ML [Zn(II)] = 1.87). The structural data (X‐ray and MM) indicate that, due to the ortho protons of the pyridyl groups and in dependence of the electronic configuration of the metal center, there is a considerable tetrahedral twist of the central MN 4 chromophores {square planar: θ = 0°; tetrahedral: θ = 90°; [Co(pap)]: θ = 15° (MM); [Ni(pap)]: θ = 16° (X‐ray), 16° (MM); [Cu(pap)]: θ = 18° (X‐ray), 18° (MM); [Zn(pap)]: θ = 23° (MM)}, and this may be enhanced by ortho‐ methyl substitution of the pyridyl donors {[Co(Me 2 pap)]: θ = 20° (MM); [Ni(Me 2 pap)]: θ = 20° (MM); [Cu(Me 2 pap)]: θ = 24° (MM); [Zn(Me 2 pap)]: θ = 31° (MM)}, and thus possibly a decrease in the complex stability of Cu(II) and Ni(II) in favor of Zn(II).