Experimental studies on the trans-influence of boryl ligands in square-planar platinum(II) complexes

A series of platinum(II) boryl complexes of general formula trans- [((CyP)-P-3)(2)Pt(Br)(BX2)], including the rare dibromoboryl species trans[(Cy3P)(2)Pt(Br)(BBr2)], were synthesized by oxidative addition of the B-Br bond of a number of bromoboranes to [Pt(PCy3)(2)]. X-ray diffraction studies were performed on several such compounds. Comparison of the Pt-Br bond lengths allowed an empirical assessment of the trans-influence of different boryl ligands. A trans-influence scale was thus deduced and the results were compared with those previously computed for compounds of the type trans-[(Me3P)(2)Pt(Cl)(BX2)].