Exploring the reactivity of white phosphorus with electrophilic carbenes: synthesis of a P4 cage and P8 clusters

Abstract

The reaction of cyclic di(amido)- and (alkyl)(amino)-carbenes with white phosphorus in benzene afford P8 clusters supported by four carbenes, or a novel type of carbene-P4 adduct.

Synthesis, Spectroscopic Characterization, and Redox Reactivity of a Cyclic (Alkyl) Amino Carbene‐Derived Arsamethine Cyanine Dye

“…The ability to readily tailor the electrochemical and photophysical properties using carbenes was intriguing to us as we have been exploring the utility of the highly π‐acidic diamidocarbenes (DACs) to stabilize low‐oxidation‐state main‐group species . We questioned if DACs could be used to produce diatomic allotropes of the group 15 elements with photophysical and/or electrochemical properties that differ from C – F .…”

“…The ability to readily tailor the electrochemical andp hotophysicalp roperties using carbenes was intriguingt ou sa sw e have been exploring the utilityo ft he highly p-acidic diamidocarbenes (DACs) [12] to stabilize low-oxidation-state main-group species. [13,14] We questioned if DACs could be used to produce diatomic allotropes of the group 15 elements with photophysical and/ore lectrochemical properties that differ from C-F.I n addition, we have set out to prepare the missing compounds in the series of carbene-stabilized group 15 diatomic allotropes (i.e.,N HC-stabilized diantimony and CAAC-stabilized diarsenic) for comparison to the DAC analogs. Herein, we report our efforts to prepare CAAC-stabilized diarsenic,t he synthesis of the first fully characterized example of an arsamethine cyanine dye of type B,a nd its one electron oxidation into an unprecedented 2-coordinate arsenic(II) radical dication.…”

Functionalization of P4 through Direct P−C Bond Formation

“…Remarkably, reacting P 4 with more electrophilic NHCs that bear carbonyl functional groups in the carbon backbones, allows isolation of P 8 clusters 40 , which are formed by [2+2]‐cycloaddition of the linear R 2 P 4 chains (Scheme ) . Furthermore, a highly electrophilic benzamido carbene was shown the insert into one P−P bond to give the expanded five‐membered cage compound 41 , which possibly also represents the initial product for other NHC‐induced activations …”

“…The incipient carbene and the t BuOH by‐product react with P 4 to generate a phosphaalkene ( 42 , Scheme ) in addition to a small amount of cation 43 that resembles the CAAC‐initiated fragmentation reported by Bertrand (cf. 34 , Scheme ) …”

“…34, Scheme12). [46] Lastly,afrustrated Lewis pair( FLP) approach, based on the use of carbene ItBu (ItBu = 1,3-bis(tert-butyl)-imidazol-2-ylidene) and B(C 6 F 5 ) 3 ,w as reported by Ta mm et al [48] The NHC was Scheme11. Reactivity of P 4 with CAACs.…”