Synthesis,characterization,and stereochemistry of S-bridged Co~(III)MCo~(III)(M = Pd~(II),Pt~(II))trinuclear complexes containing two non-bridging thiolato groups:building blocks for the construction of chiral heterometallic aggregates

摘要

The reaction of fac(S)-[Co(aet)_3](aet = aminoethanethiolate)with[PdCL_4]~(2-)in a 2:1 ratio in water gave an S-bridged Co~(III)Pd~(II)Co~(-1)trinuclear complex composed of two mer(S)[Co(aet)_3]units,[Pd{Co(aet)_3}_2]_~(2+)([1]_~(2+)).In[1]_~(2+),each of the two mer(S)-[Co(aet)_3]units is bound to a square-planar Pd~(II)ion through two of three thiolato groups,leaving two non-bridging thiolato groups at the terminal.Of two geometrical forms,syn and anti,possible for[Pd{Co(aet)_3}_2]_~(2+),which arise from the difference in arrangement of two terminal non-bridging thiolato groups,[1]_~(2+)afforded only the syn form.A similar reaction of fac(S)-[Co(aei)_3]with[PtQ_4]_2~ or ?ra".s-[PtCl_2(NH_3)_2]produced an analogous Co~(III)Pt~(II)Co~(II)trinuclear complex,[Pt{Co(aet)_3}_2]_~(2+)([2]_~(2+)),but both the syn and anti forms were formed for[2]_~(2+).Complexes[1]_~(2+)and syn-and anti-[2]_~(2+),which exclusively exist as a racemic(AA/AA)form,were successfully optically resolved with use of[Sb_2(.R,R-tartrato)_2]_2~ as the resolving agent.The reaction of syn-[2]_~(2+)with[AuCl{S(CH_2CH_2OH)_2}]led to the formation of an S-bridged Co~(III)_4Pt~(II)_2Au~(I)_2 octanuclear metallacycle,[Au_2{Pt[Co(aet)_3]_2}_2]~(6+)([3]~(6+)),while the corresponding reaction of anti-[2]_~(2+)afforded a different product({[4]~(3+)}n)that is assumed to have a polymeric structure in {[Au{Pt[Co(aet)_3]_2}]~(3+)},.