2-Pyridylmetallocenes, part IV. Cycloplatination of 2-pyridyl-ferrocene, -ruthenocene and –cymantrene. Molecular structures of σ-Pt{CpM[C5H3(2-C5H4N)]}Cl (DMSO) (M = Fe, Ru) and σ-Pt{CpFe[C5H3(2-C5H4N)]}(acac)

Abstract

The 2-pyridylmetallocenes [C5H3R(2-C5H4N)]MLn (1a–e, MLn=FeCp, RuCp, Mn(CO)3, R=H, CH3) react with cis-[PtCl2(DMSO)2] to give the cycloplatinated complexes σ-Pt{LnM[C5H2(2-C5H4N)(R)]}Cl (DMSO) (MLn=FeCp (R=H: 2a; R=Me: 2b), RuCp (R=H, 3a; R=Me, 3b), Mn(CO)3 (R=H, 4)). The reaction of 1a with the chiral sulfoxide complexes cis-[PtCl2{S(O)Me(p-C6H4Me)}2] or K[PtCl3S(O)Me(p-C6H4Me)] yields a mixture of σ-Pt{CpFe[C5H2(2-C5H4N)(R)]}Cl[S(O)Me(p-C6H4Me)] diastereomers (RpRS/SpSS)- and (RpSS/SPRS)-5. Treatment of 2a with sodium pentane-2,4-dionate (“Na(acac)”) gives the bischelate σ-Pt{CpFe[C5H3(2-C5H4N)]}(acac) (6a). Refluxing solutions of 2a with glycine in the presence of sodium methoxide yields the amino acidato complex Pt{CpFe[C5H3(2-C5H4N)]}(gly) 6b. The molecular structures of 2a, b, 3a and 6a have been determined by X-ray diffraction. 2a, b and 3a show a trans-N, S configuration of the pyridine nitrogen and the DMSO sulfur atoms.