N,N-Bis(diphenylphosphino)-1,2-dimethylpropylamine

The diphenylphosphine groups in the title compound, C29H31NP2, are staggered relative to the PNP backbone. The N atom adopts an almost planar geometry with the two P atoms and the C atom attached to it, in order to accommodate the steric bulk of the phenyl groups and the alkyl group. Three C atoms of the 1,2-dimethylpropylamine group are disordered over two positions in a 9:1 ratio. The molecules pack diagonally in the unit cell across the ac plane in a head-to-tail fashion.

The diphenylphosphine groups in the title compound, C 29 H 31 NP 2 , are staggered relative to the PNP backbone. The N atom adopts an almost planar geometry with the two P atoms and the C atom attached to it, in order to accommodate the steric bulk of the phenyl groups and the alkyl group. Three C atoms of the 1,2-dimethylpropylamine group are disordered over two positions in a 9:1 ratio. The molecules pack diagonally in the unit cell across the ac plane in a head-totail fashion.

N,N-Bis(diphenylphosphino)-1,2-dimethylpropylamine
Nicoline Cloete, Hendrik G. Visser, Andreas Roodt, Jontho T. Dixon and Kevin Blann S1. Comment Diphosphinoamine (PNP) ligands with various substituents on both the P and N atoms have proven to be very effective in ethylene tetramerization catalyst systems and have been shown to produce 1-octene in good selectivity (Bollmann et al., 2004). It seems that the substituents on the N atom profoundly affected the catalyst productivity. This paper forms part of a structural and kinetic investigation into the mechanism of the catalytic cycle.
The crystals of the title compound, (I), crystallize in the triclinic space group. All bond distances and angles in (I) ( Figure 1a) are considered to be normal and fall within the range reported for similar complexes (Keat et al., 1981;Cotton et al., 1996;Fei et al., 2003). A slight disorder of 12% is observed in the 1,2-dimethylpropylamine substituent (Figure 1 b). The distance of N1 from the P1-P2-C1 plane was calculated as 0.216 (2) Å. The geometry around the phosphorous ligands is distorted from tetrahedral geometry with C-P-C angles being the most distorted (varying from 99.56 (7)° to 99.78 (7)°). The P1-N1-P2 angle is 117.83 (7)°.

S2. Experimental
1,2-Dimethylpropylamine (0.01 mole, 0.811 g) was dissolved in dichloromethane (30 ml) and placed in an ice bath. Triethylamine (0.03 mol, 4.22 ml) was added to the solution while it was being stirred. Chlorodiphenylphosphine (0.02 mol, 3.62 ml) was slowly added to the reaction mixture. The ice bath was removed after 30 minutes and the reaction mixture was allowed to stir at room temperature for a further 12 hrs.
The dichloromethane was removed under reduced pressure. A mixture of hexane (20 ml) and toluene (2 ml) was added to the remaining white powder and was passed through a column containing neutral activated alumina (35 g). The solvent of the eluent was removed under reduced pressure and the white precipitate was collected. The product was recrystallized from methanol, single colourless crystals were obtained (yield 2.551 g, 56.1%) the next day which were suitable for Xray crystallography.