Linking ethynyl bridges

Multi-ferrocenyl phthalocyanines having up to 16 ferrocene units per molecule have been built with oxyethylene linkers to create aliphatically linked ferrocene units, and ethynyl bridges have been used to create ferrocenyl-linked tetrapyrroles of both phthalocyanine and porphyrin types with unsaturated links the porphyrins have two ferrocene units, which are placed on opposite meso positions. Both the aliphatically linked and the ethynyl-linked compounds were shown to exhibit no electrochemical communication between ferrocene units. ... 

D Zn(DPP)-Zn(DPPi. A is 1,6 times larger than that of l)-Zn(l, )PP)-A. The larger /> value is as.soeiated with two ZmDPP) units linked logetlier by an ethynyl bridge eoiinecting the ehromophorcs at their 5- and 5 -positions. 

Linking Blocks via Simultaneous Construction of Ethenyl and Ethynyl Bridges Tolanes and Ethenes... 

Apart from the construction of phenanthrenes, carbene complexes have also been used for the synthesis of more extended polycyclic arenes. An unusual dimerization of chromium coordinated ortbo-ethynyl aryl carbenes results in the formation of chrysenes (Scheme 37) [81]. This unusual reaction course is presumably due to the rigid C2 bridge that links the carbene and alkyne moieties, and thus prevents a subsequent intramolecular alkyne insertion into the metal-carbene bond. Instead, a double intermolecular alkyne insertion favored by the weak chromium-alkyne bond is believed to occur forming a central ten-membered ring that may then rearrange to the fused arene system. For example, under typical benzannulation conditions, carbene complex 97 affords an equimolar mixture of chrysene 98a and its monochromium complex 98b. The peri-interactions between the former alkyne substituent (in the 5- and 11-positions) and the aryl hydrogen induce helicity in the chrysene skeleton. 

The polycondensation of acetylene-substituted metallocenes has yielded polymers containing backbone aUcyne bridges. The synthesis of l-iodo-2-methoxy-methyl-3-ethynylferreocene and l-iodo-2-(N,N-dimethylamino methyl)-3-ethynyl-ferreocene was reported by Plenio and coworkers. Polymerization of these ferrocene-based complexes gave rise to soluble bimodal 1,3-linked ferrocene-acetylene polymers. Polymers exhibiting optical activity or functionalized sidechains were produced via Sonogashira coupling reactions. 

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