Synthesis, Characterization And Properties Of Novel Tp*W/Cu(Ag)/S Clusters

Mo(W)/Cu(Ag)/S clusters have been extentsivly investgated because of theirinteresting structural chemistry and various potential applications in biological systemsand optoelectronic materials. In the previous reports, many Mo(W)/Cu(Ag)/S clustershave been synthesized derived from thiometallate anions [AMo(W)S3]-(A=O, S, Cp*).In recent years, some Tp*-coordinated Mo(W)/S complexes draw our attention due totheir good solubility and special steric effect. To study the reactivity of these precursorcomplexes toward Cu(I) and Ag(I) and explore the structural chemistry and thethird-order nonlinear optical (NLO) properties of the resulting W/Cu(Ag)/S clusters, wedeliberately chose [Et4N][Tp*WS3](1) as a precursor cluster, which has better solubilityin organic solvents, to react with different Cu()/Ag() salts. A set of W/Cu(Ag)/Sclusters with interesting cluster sturctures were isolated therefrom. The third-order NLOproperties of some of these clusters in solution were also investigated. The main resultswere briefly summarized as follows:1. We selected six P-ligands: one monophosphine ligand (PPh3), three diphosphineligands (dppm, dppp, bdppmapy) and two tetraphosphine ligands (dppeda, dpppda), andcarried out their reactions of [Et4N][Tp*WS3](1) with two equiv. of CuX (X=Br, SCN)or [Cu(MeCN)4]PF6. Six new [Tp*WS3Cu2]-based clusters,[Tp*W(μ3-S)(μ-S)2Cu2Br(PPh3)](2),[Tp*W(μ3-S)(μ-S)2Cu2(SCN)(dppm)]2·MeCN·Et2O (3·MeCN·Et2O),[Tp*W(μ3-S)(μ-S)2Cu2(dpppds)](PF6)·1.25MeCN (dpppds=1,3-bis(diphenylphosphino)propane disulfide)(4·1.25MeCN),[Tp*W(μ3-S)(μ-S)2Cu2(bdppmapy)](PF6)·3MeCN (5·3MeCN) and{[Tp*W(μ3-S)(μ-S)2Cu2]2(L)]}(PF6)2·Sol (6·Et2O: L=dppeda, Sol=Et2O;7·MeCN·CH2Cl2: L=dpppda, Sol=MeCN·CH2Cl2) were produced. Compounds2–7were fully characterized by elemental analysis, IR, UV-vis,1H and31P NMR and ESImass spectroscopy. The solutions of these clusters were confirmed to exhibit improved third-order NLO performances relative to that of1.2. Reactions of the precursor cluster1with [Cu2(4,4-bipy)(PPh3)4(MeCN)2](BF4)2inthe presence of two different sulfur sources produced two unique hexadecanuclearclusters. When Na2S was introduced into the reaction system, it afforded a cubic cluster[Tp*W(μ3-S)3(μ3-S’)Cu3]4(8), whose eight corners are occupied by four incompletecubane-like [Tp*W(μ3-S)3Cu3] fragments and four μ3–S’ atoms. While analogousreactions of1with [Cu2(4,4-bipy)(PPh3)4(MeCN)2](BF4)2in the presence of S8formedone tetrahedral cluster [Tp*W(μ3-S)3Cu3(4,4’-bipy)1.5(μ3-DMF)]4(PF6)8(9). The fourcorners of such a tetrahedral frameworks are occupied by four[Tp*W(μ3-S)3Cu3(μ3-DMF)] fragments which are interconnected by six4,4’-bipyligands. Relative to that of1, the third-order NLO responses of8in solution wereenhanced while those of9seemd very weak.3. Reaction of [Et4N][Tp*W2S8](10) with equimolar CuBr or AgBr in the presenceof PPh3or py afforded three neutral clusters [Tp*WS(μ-S)2W(μ3-S)2M’(PPh3)]2·Sol(11·0.5Et2O: M’=Cu, Sol=0.5Et2O;12·4CH2Cl2·MeCN: M’=Ag, Sol=4CH2Cl2·MeCN) and [Tp*WS(μ-S)2W(μ3-S)2Cu(py)]2(13). They have similarhexanuclear structures in which two [Tp*WS(μ-S)2] species link two W centers of thecentral [W(μ3-S)2M’(L)]2(L=PPh3or py) cluster core via a couple of μ-S bridges. Thesolutions of11-13exhibited very weak third-order NLO responses under ourexperimental conditions.