Preparation and characterization of di(tertiary phosphines) with electronegative substituents. 1. Symmetrical derivatives

Pnicogen Bonds: A New Molecular Linker?

“…The marked peaks can be attributed to the P···P through-space coupling. In a 13 C- 31 P}-NMR spectrum the signals coincide to give a singlet verifying this theory. Unfortunately, no evidence for 1 J PP' coupling can be found in the 31 P NMR spectrum, since both phosphorus atoms are magnetically equivalent, which results in a singlet.…”

“…Recently, we have found indications for a PÀP nonbonding interaction in a 13 C{ 1 H}-NMR spectrum of a previously synthesized C 2 -symmetric ortho-carbaborane derivative, [12] see Figure 1b. Owing to the low natural abundance of 13 C, only one of both cage carbon atoms is NMR active, which causes a break of the C 2 symmetry and renders the P atoms chemically and magnetically inequivalent.…”

“…Owing to the low natural abundance of 13 C, only one of both cage carbon atoms is NMR active, which causes a break of the C 2 symmetry and renders the P atoms chemically and magnetically inequivalent. As a result, a sophisticated coupling pattern of higher order can be found in the NMR spectrum, see Figure 1a.…”

“…Further examples of P À P nonbonding interactions can be found in previously reported NMR spectra. [13][14][15][16] One might expect that the coupling may result of a repulsive interaction from the lone pairs of electrons at phosphorus. However, we found a P'C'C bond angles of 114.1 and 116.38 in the solid-state structure indicating an attractive interaction instead of a repulsive one, because this angle is smaller compared to the unsubstituted compound.…”

Enantiomerically Pure Bis(phosphanyl)carbaborane(12) Compounds

“…1,2-Dicarba-closo-dodecaborane (12) [ortho-carbaborane (12)] is of interest as a C 2 -symmetric backbone for phosphanes. Most research is focussed on disubstituted derivatives in which ortho-carbaborane (12) unique electronic properties, with electron-withdrawing and electron-delocalising ability, change the electronic properties of the phosphanes dramatically.…”