Stereochemically inactive lone pairs in phosphorus(iii) compounds: the characterisation of some derivatives with the 2,5-(CF3)2C6H3 (Ar) substituent and their complexation behaviour towards Pt(ii) species

Abstract

Some new phosphorus(III) derivatives Ar(2)PX (X = Br, Cl, F or H), ArPX(2) (X = Br or Cl), Ar(3)P and Ar(t)BuPCl, with the 2,5-bis(trifluoromethyl)phenyl (Ar) substituent on phosphorus, have been prepared, and characterised by (31)P and (19)F NMR solution-state spectroscopy. The complexing ability of Ar(2)PX, Ar(3)P and Ar(t)BuPCl towards the dimeric platinum(II) complexes [PtY(μ-Y)(PEt(3))](2) (Y = Cl or Br, the latter for X = Br only) has also been investigated. Single-crystal X-ray diffraction studies at low temperature have been carried out for Ar(3)P, Ar(2)PCl and the hydrolysis or oxidation products Ar(2)P(H)OH and Ar(2)P(O)OH. The structures of Ar(3)P and Ar(2)PCl are particularly interesting as in each compound the geometry around P is approximately octahedral. In Ar(3)P there are three short contacts to fluorine as well as the three bonded C atoms for both of the independent molecules in the unit cell. For Ar(2)PCl there are two short P-F contacts, and the octahedron is completed by a weak P-P interaction to a neighbouring molecule. In both instances the lone pair on the P(III) centre appears to be stereochemically inactive, and does not play a significant role in the structure.

Synthesis and characterisation of selected group 14 derivatives of the 2,5-(CF3)2C6H3 (Ar) ligand

“…The main difference is that further substitution to Ar 3 SiX occurs, followed by rapid halogen exchange to yield This journal is © The Royal Society of Chemistry 2012 Ar 3 SiF. This result and those for tin(IV) discussed below suggest that reaction is more facile with ArLi, particularly where the E-X bond is weaker, leading to more Ar groups on E. In the reactions of ArLi with phosphorus(III) halides, even 1 : 1 molar ratios of reactants yielded more Ar 2 PX than ArPX 2 , suggesting that the latter may react more readily than PX 3 with ArLi, 20 and this may well be true for ArSiX 3 relative to SiX 4 . No evidence for 1 : 1 products was found here.…”

“…With only one bulky ortho-CF 3 group this ligand does not confer the same kinetic stability as fluoromes or fluoroxyl groups, but it should have similar electron-withdrawing properties. We have now extended the previous work 20 to the synthesis and characterisation of group 14 compounds with two or more Ar substituents attached to the central element Si, Ge or Sn. There have been no previous reports of structurally characterised group 14 derivatives of the Ar ligand.…”

“…1 In a recent paper, we described the synthesis, characterisation and complexation behaviour towards Pt(II) of some phosphorus derivatives of the 2,5-(CF 3 ) 2 C 6 H 3 (Ar) substituent, formed by lithiation of 1,4-(CF 3 ) 2 C 6 H 4 (ArH) and subsequent reaction with a phosphorus(III) halide. 20 The hydrocarbon starting material has the advantage that all four potential lithiation sites are equivalent, so only one set of derivatives was produced from each reaction, with the CF 3 groups always in the 2-and 5-positions. With only one bulky ortho-CF 3 group this ligand does not confer the same kinetic stability as fluoromes or fluoroxyl groups, but it should have similar electron-withdrawing properties.…”

The structures of 1:1 and 1:2 adducts of phosphanetricarbonitrile with 1,4-diazabicyclo[2.2.2]octane

“…This must mean that the lone pair of electrons on the P is not sterically active. There is precedence for this in other P III compounds (Capel et al, 2011). Diagram for 1 showing the interaction of P1 with N1 (shown as dashed lines), forming chains along the a-axis direction.…”

Nitrogen, phosphorus, arsenic, antimony and bismuth

“…The synthesis of a number of phosphorus(III) derivatives containing the bulky electron-withdrawing substituent C 6 H 2 -2,4,6-(CF 3 ) 3 has been described. 99 Interestingly, in the solid state the phosphorus atom adopts a distorted octahedral geometry in which the fluorine atoms of the substituent interact with the pnictogen. The reaction of perfluoroalkyl-containing Grignard reagent with PCl 3 or PBr 3 followed by oxidation with H 2 O 2 has been shown to be a route to compounds P(O)(OH) 2 R f .…”