Synthesis, characterization, and stereochemistry of S-bridged CoIIIMCoIII(M = PdII, PtII) trinuclear complexes containing two non-bridging thiolato groups: building blocks for the construction of chiral heterometallic aggregates

Abstract

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(III) 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(aet)(3)] with [PtCl(4)](2-) or trans-[PtCl(2)(NH(3))(2)] produced an analogous Co(III)Pt(II)Co(III) 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(DeltaDelta/LambdaLambda) 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(2)CH(2)OH)(2)]] led to the formation of an S-bridged Co(III)(4)Pt(II)(2)Au(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+)](n).

Rational synthesis of hexanuclear metallacycles by alkylation reactions of an S-bridged CoIIIPdIICoIII trinuclear complex containing non-binding thiolato groups

“…This absorption spectrum coincides well with that of 2 mol of [Pd{Co(aet) 2 (bztea)} 2 ] 4+ (bztea = benzyl-2-thioethylamine), in which two non-bridging S atoms for [Pd{Co(aet) 3 } 2 ] 2+ is bound by benzyl groups [23]. Furthermore, the 13 3 ] octahedra in each Co III Pd II Co III trinuclear unit have the same chiral configuration to give the D 2 or K 2 form, like the parental [Pd{Co(aet) 3 } 2 ] 2+ [22]. Furthermore, the same configurational Co III Pd II Co III trinuclear units are connected by o-xyl 2+ moieties to afford only the D 4 and K 4 isomers.…”

“…Treatment of a dark brown aqueous solution of [Pd{Co(aet) 3 } 2 ] 2+ , which has two non-bridging thiolato groups at the terminal [22], with o-dibromoxylene (oxylBr 2 ) in a 1:1 ratio gave a dark-red solution. When the reaction solution was chromatographed on an SP-Sephadex C-25 column, only one red-brown band was eluted with a 1.0 mol dm À3 NaCl aqueous solution.…”

“…In fact, a number of metal complexes with sulfide ligands have been derived from thiolato complexes by treatment with alkyl halides or alkyl sulfate [13][14][15][16][17][18][19][20]. Recently, we have shown that two nonbridging thiolato groups in an S-bridged Co III Pd II Co III trinuclear complex, [Pd{Co(aet) 3 } 2 ] 2+ , which selectively forms a racemic-syn isomer [21,22], are readily alkylated by benzyl bromide to produce [Pd{Co(aet) 2 (bztea = benzyl-2-thioethylamine), retaining the racemicsyn configuration of the trinuclear structure, although the corresponding reaction with methyl iodide or dimethyl sulfate is accompanied by the syn-to-anti isomerization [23]. Thus, it is expected that the use of dibromoxylene, instead of benzyl bromide, would lead to the production of some cyclic metalloaggregates, in which the [Pd{Co(aet) 3 } 2 ] 2+ cations are linked by xylene fragments through C-S bonds.…”

15 Noble metals

“…Reaction of the syn-isomer with [AuCl{S(CH 2 CH 2 OH) 2 }] led to the formation of an S-bridged octanuclear metallocycle, [Au 2 {Pt[CoL 3 ] 2 } 2 ] 6+ . 225…”

Linear-Type S-Bridged Triruthenium Complexes with Aliphatic Aminothiolate Ligands: Synthesis, Characterization, and Properties

“…Our continued interest in the stereochemical and electrochemical properties of S-bridged polynuclear complexes composed of fac- ( S )-[M(aet) 3 ] units prompted us to prepare the mononuclear fac- ( S )-[Ru(aet) 3 ] that could be available as the starting complex for the construction of a variety of S-bridged polynuclear structures. In the course of this work, we found that the reactions of Ru III or Ru II with Haet led to the direct isolation of an S-bridged triruthenium complex having two fac- ( S )-[Ru(aet) 3 ] units, [Ru{Ru(aet) 3 } 2 ] 2+ , which is easily oxidized to give the corresponding tricationic species, [Ru{Ru(aet) 3 } 2 ] 3+ .…”