Alkynyl complexes, rhenium

Figure 42 Decanuclear silver(i)—rhenium(i) alkynyl complexes 95a-d.

Other work has demonstrated that it is possible to switch ON and OFF luminescence by reduction/oxidation, and it has been demonstrated that such switching is possible inside an OTTLE cell. Many alkynyl complexes, especially those of rhenium, platinum,copper, silver or gold " are highly luminescent from their excited MLCT or metal perturbed 71 states. This opens up the possibility to significantly influence their emissive properties by redox processes. An interesting example is found in recent work of Wong et Unlike other rhenium(I)-alkynyl complexes, heterobimetallic... 

In 1995, Yam and coworkers reported the first series of luminescent rhenium(i) diimine alkynyl complexes [Re(CO)3( Bu2bpyXC=C-R)] (R = alkyl or aryl) (Scheme... 

The robustness of the rhenium(i) diimine alkynyl systems and rich photophysical behavior have rendered them suitable as metalloligands for the synthesis of mixed-metal complexes. It is well-known that organometallic alkynes exhibit rich coordination chemistry with Cu(i), Ag(i) and Au(i) [214-218], however, photophysical properties of these r-coordinated compounds are rare. Recent work by Yam and coworkers has shown that luminescent mixed-metal alkynyl complexes could be synthesized by the metalloligand approach using the rhenium(i) diimine alkynyl complexes as the z -ligand. Reaction of the rhenium(i) diimine alkynyl complex [Re(bpy)(CO)3C=CPh] with [M(MeCN)4]PF6 in THF at room temperature in an inert atmosphere afforded mixed-metal Re(i)-Cu(i) or -Ag(i) alkynyl complexes (Scheme 10.31) [89]. Their photophysical properties have also been studied. These luminescent mixed-metal complexes were found to emit from their MLCT[d7i(Re) —> 7i (N N)] manifolds with emission bands blue-shifted relative to their mononuclear precursors (Table 10.5). This has been attributed to the stabilization of the dTi(Re) orbital as a consequence of the weaker t-donating ability of the alkynyl unit upon coordination to the d metal centers. 

Exploration of the constmction of mixed-metal luminescent materials using rhenium(i) diimine alkynyl complexes in a terminal mode has also been of interest... 

Pentanedionates, with Ru and Os half-sandwiches, 6, 483 Pentanuclear silver(I)-rhenium(I) alkynyl rigid-rod complex, preparation, 2, 229-230... 

Molecular wires, 208 211 in which two metal centers are connected by an unsupported C3 chain, as in compound 191, have been generated by addition of BF3 to binuclear bridged (l-alkynyl)carbene complex lw (Scheme 80).27 29,212 Similar compounds were derived from tungsten, rhenium, and iron moieties. A binuclear complex 192 containing a C5 bridge has been also obtained 27... 

A series of rhenium(I) complexes [Re(CO)3(N-N) ( C=C -R)] containing conjugated alkynyl ligands displayed remarkable luminescence properties. The origin of the... 

The introduction of further metals into these systems can be achieved by placing pyridyl-functionalized alkynyl groups in the axial positions 91 and then coordinating rhenium bipyridine complexes 92. Again, electron delocalization was observed along the heterobimetallic axis. The inclusion of such donors in both axial positions allows a wide range of metal subunits to be introduced into these systems. 

In the case of formation of the rhenium(I) complex 69 (Scheme 38), the alkynyl reagent [I(C=CSiMe3)Ph][OTf] has been used to add an additional alkyne functionality to convert a diyne to a triyne. ... 

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