Abstract
The haloacyltris(trifluoromethyl)borate anions [(CF~3~)~3~BC(O)Hal]^−^ (Hal=F, Cl, Br, I) have been synthesized by reacting (CF~3~)~3~BCO with either MHal (M=K, Cs; Hal=F) in SO~2~ or MHal (M=[__n__Bu~4~N]^+^, [Et~4~N]^+^, [Ph~4~P]^+^; Hal=Cl, Br, I) in dichloromethane. Metathesis reactions of the fluoroacyl complex with Me~3~SiHal (Hal=Cl, Br, I) led to the formation of its higher homologues. The thermal stabilities of the haloacyltris(trifluoromethyl)borates decrease from the fluorine to the iodine derivative. The chemical reactivities decrease in the same order as demonstrated by a series of selected reactions. The new [(CF~3~)~3~BC(O)Hal]^−^ (Hal=F, Cl, Br) salts are used as starting materials in the syntheses of novel compounds that contain the (CF~3~)~3~BC fragment. All borate anions [(CF~3~)~3~BC(O)Hal]^−^ (Hal=F, Cl, Br, I) have been characterized by multinuclear NMR spectroscopy (^11^B, ^13^C, ^17^O, ^19^F) and vibrational spectroscopy. [PPh~4~][(CF~3~)~3~BC(O)Br] crystallizes in the monoclinic space group __P__2/c (no. 13) and the bond parameters are compared with those of (CF~3~)~3~BCO and K[(CF~3~)~3~BC(O)F]. The interpretation of the spectroscopic and structural data are supported by DFT calculations [B3LYP/6‐311+G(d)].