Poly-yne complexes

Spectroscopic data for the Ti-poly-yne complex Ru f/ -Tp (CO)2WC6W (CO)2Tp (CO)2(PPh3)2 confirm the presence of two chemically distinct... 

Poly-yne complexes of Group 10 metals (Ni, Pd, Pt) were first synthesized by Hagiwara and co-workers in 1978-82 using condensation reactions of traits-(PBu3)2MCl2 and ran5 -(PBu3)2M(C=CR)2 in amine... 

Metal-acetylide complexes have been used as a unit of organometallic polymers that have metallic species in the main chain [20]. Representative examples are metal-poly(yne) polymers (19) of group 10 metals depicted in Scheme 5. These polymers are easily prepared from M(PR3)2Cl2 (M=Pt, Pd) and dialkynyl compounds catalyzed by Cu(I) salts in amine. Recently, this synthetic method was successfully applied to the construction of metal-acetylide dendrimers. 

Metal-acetylide complexes including metal-poly(yne) polymers often show unique properties [21-23]. Thus, metal-acetylide dendrimers are of interest because amplification of the functionality due to metal-acetylide units based on three-dimensional assembly with a regular dendritic structure is expected. 

The preparation of poly-ynes from diiodoacetylene has recently been carried out in the presence of Ni/dppe complexes (Eq. 4) [39] ... 

IV. Metal Cluster Complexes Derived from 1,3-Diynes or Poly-ynes. 130... 

The presence of multiple C C moieties in di- and poly-ynes hints at a vast potential for expansion of this chemistry. Recent developments in the chemistry and material properties of these complexes have led to a surge of interest in the chemistry of these highly unsaturated ligands. Some of these results have been the subject of several recent short reviews and highlight articles. 

The presence of multiple C=C moieties affords the potential to assemble novel arrays of metal centers by combinations of a- and tt-bonding interactions. " However, examples of multimetallic complexes containing poly-yne and poly-yndiyl ligands are limited, although preliminary reports suggest that there is much scope for the preparation of new structural types. 

METAL CLUSTER COMPLEXES DERIVED FROM 1,3-DIYNES OR POLY-YNES... 

Many examples of metal cluster complexes featuring diyne or higher poly-yne ligands are known, and have generally been obtained by three main routes. 

In general, sources of metal cluster fragments, such as Ru3(CO)io(NCMe)2 or Ru3(/i-dppm)(CO)io react readily with 1,3-diynes or poly-ynes initially to give alkyne complexes, which readily undergo further reactions as a result of activation by the cluster core. 

B. Survey of Complexes Formed in Reactions of Cluster Carbonyls with Diynes or Poly-ynes... 

A problem with DFT that is not restricted to intermolecular complexes is what might be called overdelocalization . In part because of problems in correcting for the classical self-interaction energy, many functionals overstabilize systems having more highly delocalized densities over more localized alternatives. Such an imbalance can lead to erroneous predictions of higher symmetry structures being preferred over lower symmetry ones, as has been observed, for instance, for phosphoranyl radical structures (Lim et al. 1996), transition-state structures for cationic [4-1-3] cycloadditions (Cramer and Barrows 1998), and in the comparison of cumulenes to poly-ynes (Woodcock, Schaefer, and Schreiner 2002). It can... 

Introduction of two or more terminal diyne units, either at a metal center or, for example, on an q-ring-metal complex, gives the possibility of generating metal-based polymers. In the case of alkynes, many examples of polymers have been described, but studies of similar systems derived from di- or poly-ynes are in their infancy.90 Two- and three-dimensional polymers can be constructed in similar fashion, extension leading (conceptually, at least) to the formation of novel carbon allotropes. 

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