Diboron complexes of binucleating bis(amidinate) ligands

The synthesis and X-ray crystal structures of the following bis(amidinate)-substituted boron halides are reported: 1,3-C6H4[C{N(SiMe3)}2BCl2]2 (3), 1,4-C6H4[C{N(SiMe3)}2BCl2]2 (4), 1,4-C6H4[C{N(SiMe3)}2B(Ph)Cl]2 (5), 1,4-C6H4[C{NCy}2BCl2]2 (6), and 1,4-C6H4[C{NCy}2B(Ph)Cl]2 (7). Compounds 3–5 were prepared by trimethylsilyl chloride elimination, while 6 and 7 were prepared via salt metathesis reactions of the appropriate dilithium bis(amidinates) with BCl3 or PhBCl2. The molecular structures of complexes 3, 5, and 6 were determined by single-crystal X-ray diffraction, along with that of the free bis(amidine) 1a.