Defying Stereotypes with Nanodiamonds: Stable Primary Diamondoid Phosphines

Abstract

Direct unequal C-H bond difunctionalization of phosphorylated diamantane was achieved in high yield from the corresponding phosphonates. Reduction of the functionalized phosphonates provides access to novel primary and secondary alkyl/aryl diamantane phosphines. The prepared primary diamantyl phosphines are quite air stable compared to their adamantyl and especially alkyl or aryl analogues. This finding is corroborated by comparing the singly occupied molecular orbital energy levels of the corresponding phosphine radical cations obtained by density functional theory computations.

Palladium‐Catalyzed C2−H Arylation of Unprotected (N−H)‐Indoles “On Water” Using Primary Diamantyl Phosphine Oxides as a Class of Primary Phosphine Oxide Ligands

“…(9‐Hydroxydiamant‐4‐yl)phosphonic dichloride (L2) : Obtained analytical data were identical to the literature data …”

“…Conversely, primary diamantyl phosphines L6 and L7 displayed activities comparable to that of L1 . We already reported that electron‐withdrawing functions at remote positions of the diamantane cage are essential to enhance air‐stability in the solid state of primary diamantyl phosphines …”

“…Previously, we reported synthetic access to structurally related primary diamantyl phosphines (4‐DiAd)PH 2 from the facile reduction of phosphonic dichlorides with LiAlH 4 . The reaction tolerates the presence of 9‐chloro or 9‐hydroxy groups on the diamondoid scaffold, and the resulting functionalized primary diamantyl phosphines (9‐hydroxydiamant‐4‐yl)phosphine ( L1 ) and (9‐chlorodiamant‐4‐yl)phosphine ( L6 ; Figure ) were reasonably air‐stable, which renders them potentially useful as ligands for transition‐metal catalysis.…”

Diamondoid Nanostructures as sp3‐Carbon‐Based Gas Sensors

“…We surprisingly found for this purely organic phosphine a S BET =138 m 2 g −1 , which is significantly higher than several reported porous composite materials . Accordingly, we measured the surface area of (9‐hydroxydiamant‐4‐yl)phosphonic dichloride ( 5 , named Cl 2 (O)P‐DiamOH) and its chlorinated analogue (9‐chlorodiamant‐4‐yl)phosphonic dichloride ( 6 , Cl 2 (O)P‐Diam‐Cl) to found much lower values S BET =40 and 25 m 2 g −1 , respectively (Supporting Information, Figure S5d). While single crystals of 5 could not be obtained, the XRD structure of Cl 2 (O)P–DiamCl, clearly reveals no voids.…”

“…Accordingly, we measured the surface area of (9‐hydroxydiamant‐4‐yl)phosphonic dichloride ( 5 , named Cl 2 (O)P‐DiamOH) and its chlorinated analogue (9‐chlorodiamant‐4‐yl)phosphonic dichloride ( 6 , Cl 2 (O)P‐Diam‐Cl) to found much lower values S BET =40 and 25 m 2 g −1 , respectively (Supporting Information, Figure S5d). While single crystals of 5 could not be obtained, the XRD structure of Cl 2 (O)P–DiamCl, clearly reveals no voids. A S BET =54 m 2 g −1 was found for the oxide H 2 (O)P–DiamOH, 2 .…”