| A family of oxorhenium(v) complexes incorporating chelated monoanionionn ONN reduced Schiff base and dianionic ONNO tetradentate ligands:synthesis, spectroscopic and electrochemical studies (2004) | |||||||||
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| The green colored complexes of the type $Re^{\mathrm{v}}O(L_{SB})Cl_{2}$, 1, have been synthesised by reacting $NBu_{4}[ReOCl_{4}]$ with $HL_{SB}$ in dry ethanol. Here, $L_{SB}$− are the deprotonated forms of N-(2-hydroxybenzyl)-2-picolylamine $(HL_{{SB}^{\mathrm{1}}})$; N-(2-hydroxybenzyl)-$N^{\mathrm{1}},N^{\mathrm{1}}$-dimethylethylenediamine $(HL_{{SB}^{\marthrm{2}}})$ and N-(2-hydroxybenzyl)-$N^{\mathrm{1}},N^{\mathrm{1}}$-diethylethylenediamine $(HL_{{SB}^{\mathrm{3}}})$. Similarly, $NBu_{4}[ReOCl_{4}]$ reacted with N,N-bis(2-hydroxybenzyl)-2-picolylamine $(H_{2}L^{\mathrm{1}})$; N,N-bis(2-hydroxybenzyl)-$N{\mathrm{1}},N^{\mathrm{1}}$-dimethylethylenediamine $(H_{2}L^{\mathrm{2}})$; N,N-bis(2-hydroxybenzyl)-$N^{\mathrm{1}},N^{\mathrm{1}}$-diethylethylenediamine $(H_{2}L^{\mathrm{3}})$; {N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)}-2-aminoethanol $(H_{2}L^{\mathrm{4}})$; {N-(2-hydroxybenzyl)-N-(2- pyridylmethyl)}-2-methyl-2-amino-1-propanol $(H_{2}L^{\mathrm{5}})$; N,N-bis(1-hydroxyethyl)-2-picolylamine $(H_{2}L^{\mathrm{6}})$, to give the monochloro complexes $Re^{\mathrm{v}}O(L)Cl$, 2. The X-ray structures of the complexes are reported.The molecular structures observed in the solid state are preserved in solution (1H NMR). In acetonitrile solution the $Re^{\mathrm{v}}O(L)Cl$, 2, display a one-electron couple, $Re^{\mathrm{vI}}O(L)Cl$+–$Re^{\mathrm{v}}O(L)Cl$, near 1.0 V vs SCE. The electrogenerated hexavalent complexes $[Re^{\mathrm{vI}}O(L)Cl]ClO_{4}$, 3, are paramagnetic and display sextet EPR spectra in solution at room temperature $(A_{av}~417 (G), g ~ 1.914).$ | |||||||||
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