Platinum acetylides

Scheme 6. Syntheses of hyper-branched platinum-acetylide polymers 20 and 21...

Scheme 7. Self-polycondensation of AB2 type platinum-acetylide monomer...

Approaches to the Synthesis of Platinum-Acetylide Dendrimers Without Protecting Groups... 

When the preparation of the second-generation dendrimer was attempted by reacting trinuclear platinum-acetylide complex (27) (Fig. 5), which is also a first... 

Scheme 8. Syntheses of first-generation platinum-acetylide dendrimer 26...

Stang and coworkers also reported the synthesis of platinum-acetylide dendrimers using 1,3,5-triethynylbenzene as the bridging ligand [27]. Their strategy was very similar to the above, and they prepared dendrimers up to the second generation. 

Scheme 11. Syntheses of second and first-generation platinum-acetylide dendrimers 33 and 34...

Fig. 6. Tetranuclear platinum-acetylide complex 35 used as the core for convergent synthesis...

Fig. 7. Third-generation platinum-acetylide dendrimer 41 with a porphyrin core...

Scheme 13. Divergent synthesis of platinum-acetylide dendrimers...

Ramakrishna G, Goodson T III, Rogers-Haley JE, Cooper TM, McLean DG, Urbas A (2009) Ultrafast intersystem crossing excited state dynamics of platinum acetylide complexes. J Phys Chem C 113 1060-1066... 

The triple bond can be reduced with hydrazine to form the vinyl complex with a cis stereochemistry about the carbon-carbon double bond (equation 223).617 The five types ol reaction between platinum acetylide complexes and aprotic compounds A—B have beer summarized. These are (a) oxidative addition (A—B is I2, IBr, ICN, Mel etc.) (b) insertior (A—B is C2(CN)4) (c) addition across the triple bond to form vinyl complexes (A—B is CF3COCI, o-tetrachloroquinone, Br, NOC1) (d) insertion into the C—H bond (A—B is (CFs)2CO) and (e) formation of five-coordinate adducts.618... 

In the case of the asymmetrically substituted platinum acetylides, SHG was detected in all samples (Table II). The symmetrically substituted bis(pyridylacetylide) complex 7c was found to be centrosymmetric. Signals were quantified by peak height analysis of several laser pulses. 

Table II. Second Harmonic Generation and UV-VIS Absorption Data in Platinum Acetylides...

The use of Pt-acetylides containing phosphine ligands was extended further by the Schanze group in 2006 [84, 85], In one contribution, they incorporated platinum-acetylide polymers into photovoltaic devices which demonstrate good device efficiency. Transient absorption studies provide definitive evidence for photoinduced electron transfer from the Pt-acetylide to PCBM by the temporal evolution of the TA spectrum, observing the formation of the PCBM radical anion at 1,050 nm. The same system was eventually demonstrated to operate as a bulk heterojunction photovoltaic device [84],... 

To understand the physical meaning of the electronic structures of platinum acetylide complexes, theoretical calculations have been employed to deduce information related to the molecular orbitals and the electronic transitions. The first theoretical... 

The extended Hiickel method, which is a semiempirical quantum chemistry method, is often used as a preliminary step in the DFT study of molecular orbital analysis. The acetylide-bridged organometallic dinuclear complexes 5.2 were studied by Halet et al. using the extended Hiickel method for qualitative analysis and DFT for additional electronic properties [97], The extended Hiickel analysis concluded that the main contribution of the Pt-C bond arises from ct type interactions while the n back-donation is very weak. The DFT/BP86 calculation gives a 2.371 eV HOMO-LUMO gap. The electronic communication parameter Hdb between the bis-ferrocene compound linked with platinum acetylide (5.3) was calculated to be 0.022 eV, compared with 0.025 eV obtained experimentally by Rapenne and coworkers using DFT and the extended Hiickel method [98],... 

Polymers and oligomers that are platinum-acetylide based have important optical and optoelectronic applications because the lowest triplet excited state involves a mixture of Ptn (dji) orbitals and organic n-conjugated orbitals that enhance the phosphorescence efficiency. Batista and Martin studied the low-lying... 

One of the most recent works on the electronic structures of platinum acetylide complexes using theoretical calculations was performed by Ding et al [104], In this... 

---