Synthesis and characterization of aryl(trifluoromethyl)bismuth compounds (R-C6H4)3-nBi(CF3)n [R=H, 4-CH3, 4-CF3, 3-F, 4-F; n=1 and 2] and the reactions of (C6H5)3-nnBi(CF3)n [n=0–3] with benzoylpyridinium chloride