title: Expanding the 3d-4f heterometallic chemistry of the (py)2CO and pyCOpyCOpy ligands: structural, magnetic and Mössbauer spectroscopic studies of two Fe(II)-Gd(III) complexes.
abstract: Complex [Fe(II)Gd(III){pyCO(OEt)pyCOH(OEt)py}(3)](ClO(4))(2) (1) crystallizes in the Cc space group and contains one hexacoordinate ferrous ion and one enneacoordinate Gd(III) ion. Complex [Fe(2)(II)Gd(III){pyCO(OEt)py}(4)(NO(3))(H(2)O)][Gd(NO(3))(5)](0.5)(ClO(4)) (2) crystallizes in the C2/c space group and contains two hexacoordinate ferrous ions and one octacoordinate Gd(III) ion. Both complexes have been prepared by the metal-assisted ethanolysis of ligands di-2,6-(2-pyridylcarbonyl)pyridine (pyCOpyCOpy, dpcp) and di-2-pyridyl ketone ((py)(2)CO, dpk), which exhibit similar structures. Mössbauer spectroscopic studies of 2 revealed the presence of two quadrupole-split doublets of equal intensities, each assigned to a ferrous site. These doublets exhibit similar isomer shifts (δ(1) = 1.14 mm s(-1), δ(2) = 1.11 mm s(-1)) but quite different quadrupole splittings (ΔE(Q1) = 3.55 mm s(-1), ΔE(Q2) = 2.74 mm s(-1)). Magnetic studies revealed weak ferromagnetic Fe(II)-Gd(III) interactions for both complexes (J(FeGd) = +0.68 cm(-1), D(Fe) = 12.0 cm(-1) for 1 and J(FeGd) = +0.03 cm(-1), J(FeFe) = -1.73 cm(-1) for 2, according to the -JS(i)S(j) spin-Hamiltonian formalism).
authors: Institute of Materials Science, NCSR Demokritos, 153 10, Aghia Paraskevi Attikis, Greece.
authors: Anastasia N
authors: AN
authors: Georgopoulou
authors: Rosa
authors: R
authors: Adam
authors: Catherine P
authors: CP
authors: Raptopoulou
authors: Vassilis
authors: V
authors: Psycharis
authors: Rafael
authors: R
authors: Ballesteros
authors: Belén
authors: B
authors: Abarca
authors: Athanassios K
authors: AK
authors: Boudalis
mesh_terms: D018360:Crystallography, X-Ray; D005296:Ferrous Compounds / Q000737:chemistry*; D005682:Gadolinium / Q000737:chemistry*; D008024:Ligands; D008280:Magnetics; D008958:Models, Molecular; D011725:Pyridines / Q000737:chemistry*; D015204:Spectroscopy, Mossbauer
chemical_list: D005296:Ferrous Compounds; D008024:Ligands; D011725:Pyridines; C540721:di-2,6-(2-pyridylcarbonyl)pyridine; D005682:Gadolinium