Na[B(hfip)4] (hfip = OC(H)(CF3)2): a weakly coordinating anion salt and its first application to prepare ionic liquids

Carbocations have played a central role in the chemical sciences for over a century. In a synthetic setting, most methods utilize stabilized tricoordinate carbocations, while there are far fewer examples of reactions featuring nonstabilized dicoordinate cations. Here, we provide an overview of recent developments in the generation of high-energy carbocations mediated by weakly coordinating anions and the C–H insertion reactions of such carbocations. Moreover, we discuss mechanistic studies of these catalytic C–H insertion reactions aimed at furthering our understanding of the reactive nature of these rarely invoked cationic intermediates.1 Introduction2 Background: Phenyl Carbocations3 Silylium/Carborane-Catalyzed C–H Insertion Reactions of Phenyl Carbocations4 Silane-Fueled, Weakly Coordinating Anion-Catalyzed, Reductive C–H Insertion Reactions of Vinyl Carbocations5 C–H Insertion Reactivity of Vinyl Carbocations under Basic Conditions6 Conclusion and Outlook

Download Full-text

Two phosphaalkene radical cations with inverse spin density distributions

Dalton Transactions ◽

10.1039/c5dt00656b ◽

2015 ◽

Vol 44 (34) ◽

pp. 15099-15102 ◽

Cited By ~ 32

Author(s):

Xiaobo Pan ◽

Xingyong Wang ◽

Zaichao Zhang ◽

Xinping Wang

Keyword(s):

Spin Density ◽

Radical Cations ◽

Density Distributions ◽

Weakly Coordinating ◽

Weakly Coordinating Anion

Two phosphaalkene radical cations have been made by using a weakly coordinating anion, and they exhibit inverse spin density distributions.

Download Full-text

Endo-Complexation of Alkylammonium Ions by Calix[4]arene Cavity: Facilitating Cation−π Interactions through the Weakly Coordinating Anion Approach

The Journal of Organic Chemistry ◽

10.1021/jo5016689 ◽

2014 ◽

Vol 79 (20) ◽

pp. 9842-9846 ◽

Cited By ~ 11

Author(s):

Carmen Talotta ◽

Carmine Gaeta ◽

Placido Neri

Keyword(s):

Π Interactions ◽

Weakly Coordinating ◽

Weakly Coordinating Anion

Download Full-text

Crystallographic evidence for structural diversity in cationic (tripyrrinato)cobalt(II) complexes

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424605000794 ◽

2005 ◽

Vol 09 (10) ◽

pp. 683-690 ◽

Cited By ~ 9

Author(s):

Martin Bröring ◽

Carsten D. Brandt ◽

Silke Köhler ◽

Maximilian Sieber

Keyword(s):

Single Crystals ◽

Anion Exchange ◽

Structural Diversity ◽

Complete Characterization ◽

Donor Ligands ◽

Highly Sensitive ◽

Weakly Coordinating ◽

Weakly Coordinating Anion ◽

Coordinate Structures

Cobalt(II) complexes of tripyrrin ligands can be transformed into cations by anion exchange using NaBAr F , a salt of a weakly coordinating anion. The complete characterization of these highly sensitive cations (probably solvate complexes) could not be achieved, but the coordination to donor ligands like nitriles or trialkylphosphanes stabilizes the cations sufficiently for the isolation of some single crystals. As the structural analyses of these donor-stabilized cobalt(II) tripyrrins reveal, either four- or five coordinate structures are formed depending on the type and size of ligand used.

Download Full-text