A new boron-based hybrid scorpionate ligand based upon one 2-mercaptopyridine (mp) and two 1-methyl-imidazoyl-2-thione (mt) units, Na[HB(mt)2(mp)] has been prepared. This new ligand together with the recently reported ligand K[HB(mp)3] have been used to prepare analogues of the original metallaboratrane complex [Ru(CO)(PPh3){κ4-SSBS-B(mt)3}]. The effect of tautomerisation of the ligand arms upon the electronic properties of the boron and metal centres is examined in an attempt to probe further the nature of the metal–boron bond within metallaboratrane complexes.
