C5B Ring Dinuclear Complexes Triple-decker Sandwiches and Dimers

2 C5B Ring Dinuclear Complexes (Triple-decker Sandwiches and Dimers) 

The electronic and magnetic properties of bridged dimetallic complexes such as 104 and 105 have been explored. Oxidation of the CoII-Co11 phenylene-bridged species 104 affords the mixed valence Con-Com complex and the diamagnetic CoIII-Co111 dication.128 Magnetic, IR, and electrochemical evidence on neutral 104 indicates weak Co-Co interaction. 

The ethynyl-linked complexes 105 were prepared and explored as potential building blocks for nonlinear optical (NLO) materials.129 Spectroscopic and cyclic voltammetry data indicate a small but real interaction between the ferrocenyl donor group and the borabenzene unit, increasing in the order Ru Ir Rh. Hyper-Rayleigh scattering revealed small values for the first hyperpolarizability / , which increases in the same order. 

Related to these dimetallic systems, though not involving transition metals, are the boratastilbene complexes such as a [ H 5 C 5 B-CH =CH-CH 4 -C H =C H P h ] (isoelectronic with distyrylbenzene chromophores) that show aggregation-dependent photophysics. In nonpolar solvents, they form tightly bound ion pairs that are poorly luminescent, but in polar solvents, or when the counter ions are encapsulated in crown ethers, strong emission is observed as a result of intramolecular charge transfer.130 

Boratabenzene-bridged multidecker sandwiches are few in number, all prepared in the Herberich group. Stacking reactions of Cp Ru(HsCsBMe) with electrophilic metal reagents gave complexes 106 and 107. 2 interestingly, 

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