title: Haloacyl complexes of boron, [(CF3)3BC(O)Hal]- (Hal=F, Cl, Br, I).
abstract: The haloacyltris(trifluoromethyl)borate anions [(CF3)3BC(O)Hal]- (Hal=F, Cl, Br, I) have been synthesized by reacting (CF3)3BCO with either MHal (M=K, Cs; Hal=F) in SO2 or MHal (M=[nBu4N]+, [Et4N]+, [Ph4P]+; Hal=Cl, Br, I) in dichloromethane. Metathesis reactions of the fluoroacyl complex with Me3SiHal (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 [(CF3)3BC(O)Hal]- (Hal=F, Cl, Br) salts are used as starting materials in the syntheses of novel compounds that contain the (CF3)3B-C fragment. All borate anions [(CF3)3BC(O)Hal]- (Hal=F, Cl, Br, I) have been characterized by multinuclear NMR spectroscopy (11B, 13C, 17O, 19F) and vibrational spectroscopy. [PPh4][(CF3)3BC(O)Br] crystallizes in the monoclinic space group P2/c (no. 13) and the bond parameters are compared with those of (CF3)3BCO and K[(CF3)3BC(O)F]. The interpretation of the spectroscopic and structural data are supported by DFT calculations [B3LYP/6-311+G(d)].
authors.affiliation: FB C-Anorganische Chemie, Bergische Universität Wuppertal, Gaussstrasse 20, 42097 Wuppertal, Germany. maik.finze@uni-duesseldorf.de
authors.forename: Maik
authors.initials: M
authors.lastname: Finze
authors.forename: Eduard
authors.initials: E
authors.lastname: Bernhardt
authors.forename: Helge
authors.initials: H
authors.lastname: Willner
authors.forename: Christian W
authors.initials: CW
authors.lastname: Lehmann
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D002586:Cesium / Q000737:chemistry; D018360:Crystallography, X-Ray; D005461:Fluorine; D007554:Isotopes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D011188:Potassium / Q000737:chemistry; D012015:Reference Standards; D013696:Temperature; D014732:Vibration
chemical_list: D001896:Boron Compounds; D007554:Isotopes; D009942:Organometallic Compounds; D002586:Cesium; D005461:Fluorine; D011188:Potassium