title: A Phosphorus Bisylide: Exploring a New Class of Superbases with Two Interacting Carbon Atoms as Basicity Centers.
abstract: Herein we present the first superbase MHPN with two interacting P-ylide entities. Unlike classical proton sponges, this novel compound class has carbon atoms as basicity centers which are forced into close proximity by a naphthalene scaffold. The bisylide exhibits an experimental pKBH+value of 33.3±0.2 on the MeCN scale and a calculated gas-phase proton affinity of 277.9 kcal mol-1(M062X/6-311+G**//M062X/6-31G*+ZPVE method) exceeding that of the corresponding monoylide by nearly 15 kcal mol-1. The origin of the unexpectedly high basicity of the new bisylide was investigated by NMR spectroscopic methods, single-crystal X-ray diffraction as well as theoretical calculations and can be partly attributed to the rapid exchange of the "acidic" proton between the two basic carbon atoms after protonation.
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032, Marburg, Germany.|FB Biologie/Chemie, Universität Bremen, Leobener Str. im NW2, 28359, Bremen, Germany.
authors.forename: Julius F
authors.initials: JF
authors.lastname: Kögel
authors.affiliation: Ruđer Bošković Institute, Bijenička c. 54, 10001, Zagreb, Croatia.
authors.forename: Davor
authors.initials: D
authors.lastname: Margetić
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032, Marburg, Germany.
authors.forename: Xiulan
authors.initials: X
authors.lastname: Xie
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032, Marburg, Germany.
authors.forename: Lars H
authors.initials: LH
authors.lastname: Finger
authors.affiliation: Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032, Marburg, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Sundermeyer
keywords: basicity; exchange interactions; phosphorus; superbases; ylides