title: Hydrogen-bonding pincer complexes with two protic N-heterocyclic carbenes from direct metalation of a 1,8-bis(imidazol-1-yl)carbazole by platinum, palladium, and nickel.
abstract: Pincer protic N-heterocyclic carbene (PNHC) complexes were synthesized by direct metalation, the formation of a metal carbon bond from an unfunctionalized CH bond in a single synthetic step. Significantly, direct metalation succeeded even for a first-row metal, nickel. The chloride complexes were isolated and then converted to the acetate, triflate, or in the platinum case, a hydride analogue. Crystal structures and (1) H, (13) C, and (15) N NMR data, as well as IR spectra, document the effects of intramolecular hydrogen bonding and the planar but flexible pincer framework. Anti-Markovnikov addition of OH bonds to alkynes, including catalyzed alkyne hydration, were demonstrated on the Pt triflate analog.
authors.affiliation: Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030 (USA), Fax: (+1) 619-594-4634.
authors.forename: David C
authors.initials: DC
authors.lastname: Marelius
authors.affiliation: Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030 (USA), Fax: (+1) 619-594-4634.
authors.forename: Evan H
authors.initials: EH
authors.lastname: Darrow
authors.affiliation: Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093-0358 (USA).
authors.forename: Curtis E
authors.initials: CE
authors.lastname: Moore
authors.affiliation: University of Massachusetts Dartmouth, North Dartmouth, MA 02747 (USA).
authors.forename: James A
authors.initials: JA
authors.lastname: Golen
authors.affiliation: Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093-0358 (USA).
authors.forename: Arnold L
authors.initials: AL
authors.lastname: Rheingold
authors.affiliation: Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030 (USA), Fax: (+1) 619-594-4634. dbgrotjahn@mail.sdsu.edu.
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Grotjahn
keywords: alkynes; carbenes; homogeneous catalysis; hydrogen bonding