Syntheses And Characterization, Luminescence Of Pt-M (M=Ag,Cu) And Ag-Au Heteronuclear Metal Alkynyl Cluster Complexes

Recently, alkynyl complexes have attracted great attention, because the alkynylgroup can coordinate to the different metals in the different modes, resulting in aspecial geometry and rich photoluminescence properities. Transition metal alkynylcomplexes, especially d8and d10transition metal, reprensent an active area of interestwith manifold emission origins depending on the structure features, as well as on thenature of the metal, alkynyl substituents, metalophillic interactions and coligangds. Inmy work, a novel series of heteronuclear alkynyl cluster complexes were prepared byreaction polymeric (MC≡CR)nor tetraalkynylplatinate (II) complexes [Pt(C≡CR)4]2–with [M2(μ-dpppy)2](ClO4)2(M=Ag，Cu). They were purified by recrystallization orcolumn chromatography. Those complexes exhibit rich luminescence properities,including photochromic properities and rubbing-chromic properities.1. Pt (II)-Ag (I) Heteronuclear Alkynyl ComplexesThere luminescent Pt (II)-Ag (I) heteronuclear alkynyl complexes have beenprepared by self-assembly reaction between tetraalkynylplatinate (II) complexes[Pt(C≡CR)4]2–and [Ag2(μ-dppy)2](ClO4)2(dppy=Diphenyl-2-pyridylphosphine).[Pt2Ag4(C≡CC6H5)8](1)[Pt2Ag4(C≡CC6H5)8]2(2)[Pt2Ag4(C≡CC6H4CH3-4)8](3)It is revealed that the phosphine ligands have not involved due to the competitionof alkynyl ligands. It has been found that the substituents on the phenylacetylide haveno effect on the molecular structures of the products, but exert a significant influenceon the emission energy of the Pt(II)-M(I)(M=Ag, Cu) heterometallic alkynylcomplexes. With the excitation λex>350nm, all the compounds in the solid orsolutions at room temperature or77K produce intense luminescence with theemissive lifetimes in the microsecond scale, indicating that the luminescence is mostlikely associated with a spin-forbidden triplet parentage. It is most interesting thatthe compound1can be transformed to compound2by rubbing method. 2. Pt2M (M=Cu, Ag) Heteronuclear Alkynyl ComplexesTo study on the structural topology and photophysical properties of d8-d10heternuclear alkynyl complexes, a series of Pt2M (M=Cu, Ag) heteronuclearcomplexes were synthesized by self-assembly reaction betweentetraalkynylplatinate(II) complexes [Pt(C≡CR)4]2–and M2(dpppy)3(MeCN)2]2+(M=Cu, Ag; dpppy=2,6-bis(diphenylphosphino)pyridine).[Pt2Ag(dpppy)2(C≡CC6H5)4](ClO4)(4)[Pt2Ag(dpppy)2(C≡CC6H4CH3-4)4](ClO4)(5)[Pt2Cu(dpppy)2(C≡CC6H5)4](ClO4)(6)[Pt2Cu(dpppy)2(C≡CC6H4CH3-4)4](ClO4)(7)All the complexes in solid states at room temperature show intensephotoluminescence with emissive lifetimes in the microsecond scale, indicating thatthe luminescence is most likely associated with a spin-forbidden triplet parentage. Ared-shift in emission energiey on going from the phenylacetylide complexs4or6to4-methylphenylacetylide counterparts5or7is suggestive of the presence ofsubstantial LMMCT[RC≡Câ†'Pt2M]. It is very interesting that the two Pt2Aghetero-trinuclear complexes display reversible photochromic properties, whereas nophotochromic properties were found in the two Pt2Cu hetero-trinuclear complexes.3. Ag (I)-Au (I) Heteronuclear Alkynyl ComplexesTo study on the structural topology and photophysical properties of d10-d10heternuclear alkynyl complexes, an Ag (I)-Au (I) heteronuclear complexe[Ag2Au2(dpppy)3(C≡CC6H5)2](ClO4)2was synthesized by self-assembly reactionbetween (AuC≡CC6H5)nand [Ag2(μ-dpppy)3]2+(dpppy=2,6-Bis(diphenylphosphino)pyridine).Compound [Ag2Au2(dpppy)3(C≡CC6H5)2](ClO4)2show intensephotoluminescence in the solid states or fluid solutions at298K with the lifetimes inthe microsecond ranges, indicating spin-forbidden triplet excited states.