BORABENZENE DERIVATIVES .25. METHYLBIS(1- METHYLBORATABENZENE)INDIUM - SYNTHESIS AND STRUCTURE - AN EXAMPLE FOR THE VARIABILITY OF SOFT STRUCTURAL PARAMETERS IN THE CRYSTALLINE ENVIRONMENT

The new boratabenzene derivative InMe(C5H5BMe)(2) has been synthesized from 2-(Me3Sn)C5H5BMe and InMe3. The compound proves fluxional on the nmr time scale with average C-2v symmetry in solution. An x-ray struc ture determination shows the existence of four molecules in the asymme tric unit differing mainly in the bonding geometry of the metal atoms with respect to the eight symmetrically independent boratabenzene liga nds. Thus the dynamical behaviour in solution is reflected in the soli d slate by the soft structural parameters of the indium-ring coordinat ion, with their variability exceeding the standard deviations of the c orresponding individual observations by an order of magnitude.