Synthesis and structural studies on fluorophenylboron azides

The fluorophenyl substituted boron chlorides (RF)2BCl (3 and 4) and dichlorides RFBCl2 (6 and 7) (RF=2,6-F2C6H3, 2-FC6H4) were prepared using the stannylated aryl transfer reagents (RF)2SnMe2 (1 and 2). The boron azides (RF)2BN3 (8–9), [2,4,6-(CF3)3C6H2]2BN3 (10) and diazides RFB(N3)2 (11 and 12) were synthesized by the reaction of the corresponding boron chlorides (RF)2BCl (3 and 4), [(CF3)3C6H2]2BCl (5) and RFBCl2 (6 and 7) with Me3SiN3. The influence of the electron withdrawing substituents on the molecular structure of these azides is discussed. The reactions were also performed in the presence of pyridine yielding the adducts (RF)2BN3·py and RFB(N3)2·py (13–16). All compounds were characterized by multinuclear NMR, vibrational (IR, Raman) spectroscopy; and the molecular structures of 1, 3, 8, 10a ([(CF3)3C6H2]2BN3/[(CF3)3C6H2]2BOH) and 14 were established by single crystal X-ray crystallography.