Syntheses and Studies of Ruthenium and Heterometallic Metal String Complexes with Modified Naphthylridylamide Ligands
Date Issued
2014
Date
2014
Author(s)
Tsai, Cherng-Shiaw
Abstract
Using 2-Phenylamino-1,8-naphthyridine (Hphany) or 2-Naphthylamino-1,8- naphthyridine (Hnaany) as organic ligands with different transition metal ions, we obtained a series of homo- and heteronuclear metal string complexes, including (4,0)-[Ni3(phany)4Cl][PF6] (1), (4,0)-[Ni3(naany)4Cl][PF6] (2), (3,1)-[Ru3(phany)4(NCS)2][PF6] (3), (4,0)-[Ni2Pd(phany)4Cl][PF6] (4), (2,2)-trans-[Mo2Ni(phany)4(NCS)2] (5), (2,2)-trans-[Mo2Co(phany)4(NCS)2] (6), (3,1)-[Mo2Ni(phany)4(NCS)2] (7), (3,1)-[Mo2Ni(phany)4(NCS)2][PF6] (8), (3,1)-[Mo2Co(phany)4(NCS)2] (9), and (3,1)-[Mo2Co(phany)4F2][PF6] (10). This dissertation is presented to study the crystal structures and the physical properties of these string complexes.
By the steric effect of terminal chloride ions and bulky phenyl and naphthyl group, compounds 1 and 2 adopt a unique (4,0)-form arrangement. And these two different substituents do not affect related properties of the resulting compounds.
X-ray single-crystal analysis shows that compound 3 exhibits a nonlinear [Ru3]7+ backbone with long Ru-Ru bond lengths. The long Ru-Ru distances observed for 3 decrease the Ru-Ru interactions and electric conductance. Magnetic measurements indicate that compound 3 is in S = ½ state. DFT calculations suggest that this unpaired electron occupies the π* orbital which is stabilized by π-acid NCS－ ligands and thus weakening the Ru-Ru π interaction.
In the synthesis of this heteronuclear compound 4, we also get pure (4,0)-form isomer by the steric hindrance of terminal chloride and phenyl group. By the coordination ability of these nitrogen atoms of this unsymmetrical Hphany ligand, we can obtain a crystallographic ordered metal arrangement.
By the one-pot synthesis and column chromatography purification, we can get compound 5 and 6. Despite using Mo2(OAc)4 as a starting material and the unsymmetrical Hphany ligand, the metal ions in these two compounds are crystallographic disordered.
With the same synthetic procedure of compound 5, we can get this thermodynamic stable compound 7. The crystal structure of this compound is well characterized, and the Mo-Mo bond distance is slightly longer than common quadruple bonding. After treatment with an oxidizing agent FcPF6, we obtain an one-electron oxidized compound 8. Due to the removal of bonding electron of Mo2 unit, the Mo-Mo bond distance is slightly longer than neutral one, and the Mo-N distances become shorter. The neutral compound 7 exhibits paramagnetic magnetism and the oxidized compound 8 shows a weak antiferromagnetic coupling.
The structure of compound 9 is similar to compound 7, and the only terminal cobalt ion is high spin electronic configuration (S = 3/2). After treatment with an oxidizing agent FcPF6, we can also obtain an oxidized compound 10. By the result of structure determination, we confirm that the oxidized reaction take place at the Co ion.
Subjects
釕金屬串
異核金屬串
萘啶
Type
thesis
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