| Research Abstract |
The new mixed cobalt (III) complexes containing 2-pyridineselenolate (pySe), [Co(pySe) (en)_2]^<2+>, [Co (pySe) (bpy)_2]^<2+>, [Co (pySe)_2 (bpy)]^+, fac- [Co (pySe)_3] were prepared and characterized by their electronic spectra, circular dichroism spectra, NMR spectra. The [Co (pySe) (en)_2] (CIO_4)_2 complex, which was spontaneously resolved, had an orthorhombic space group of P2_1 2_1 2_1, with a=12.316 (3), b=13.012 (2), c=11.728 (3) A,and Z=4. The refinement of 2845 reflections (Mo Kalpha radiation) led to R=0.056. The Co-N bond trans to the pySe selenium atom was longer by 0.045 A than the cis one. The trans influence induced by the thiolate of the similar 2-pyridinethiolate (pyS) is less than the present pySe's one. The geometrical ligand site preference of selenolate groups which are located at fac geometry in the tris (pySe) complex. Also, the new rhodium (III) complexes, [Rh (pySe)_2(PPh_3)_2]^+, fac- [Rh(pySe)_3] were prepared.
The new palladium (II) complexes [PdCl_2(pySeBz)_2] and [PdCl_2(pySBz)_2] were prepared (pySeBz and pySBe denote (2-pyridyl) benzylselenide and (2-pyridyl) benzylsulfide). The pyrolysis of [PdCl_2(Me_2S)] in the solid state was resulted in PdS through the PdCl (SMe) as an intermediate. On the other hand, the pyrolyses of the complexes [PdCl_2(pySeBz)_2] and [PdCl_2(pySBz)_2] in the solid state were resulted in [Pd (pySe)_2] and [Pd(pyS)_2], respectively. The recrystalization from CHCl_3 solution of [PdCl_2(pySeBz)_2] at the room temperature was, however, resulted in [PdCl_2(pySepy-N,N')] (pySepy denotes 2,2'-dipyridylselenide), which was confirmed by X ray structural analysis. This novel ligand-coupling in the transition metal complex will give a useful organic synthesis route.
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