Alkynyl hexanuclear complex

The influence of electronic effects on the binding mode of tetraalkynylplatinate anions is apparent in the reactions of compounds of general formula Li2[Pt (C=CR)4] with thallium(l) nitrate [72]. For electrrai-rich alkynyl moieties (R = p-tolyl, 1-naphtyl), discrete hexanuclear structures are obtained (Scheme 16, top), in which each Tl center interacts with four C=C triple bonds and not with the platinum atom. The introduction of a remote electron-withdrawing substituent oti the alkynyl unit (R = p-CFsC lU) induces a dramatic change in the structure of the Lewis acid-base complex each platinum atom now involves in donor-acceptor bonds with two thaUium(I) ions (Pt-Tl 2.9355(5) and 3.0272(5) A), one oti each face of its coordination plane. These Tl2Pt units are interconnected by weak interactions of thallium with the Jt-elecfron density of the triple bonds. 

Yao, H. Sabat, M. Grimes, R. N. 2002. Wired multidecker sandwich assemblies, stepwise construction of a hexanuclear benzene-centered Tris(alkynyl triple-decker) Complex. Organometallics, 21 2833-5. 

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