(4-Methoxybenzoylmethyl)triphenylphosphonium trifluoromethanesulfonate

Colourless crystals of the title compound, C27H24O2P+·CF3SO3 −, have been prepared by the addition of a solution of AgCF3SO3 in methanol to a solution of (4-methoxybenzoylmethyl)triphenylphosphonium bromide in dry methanol. There are two crystallographically independent molecules in the asymmetric unit. The crystal structure is stabilized by inter- and intramolecular C—H⋯O hydrogen bonds and further stabilized by C—H⋯π interactions.

In this communication we have reported the preparations and structures of new tri-folourosulfonate phosphonium ylides.
In the asymmetric unit of (I), there are two crystallographically independent molecules (Fig. 1). A comparison of the bond lengths and bond angles in (I) shows that the phosphonium cation as a ligand is electrostatically under the influence of an anionic part of OTf in the unit cells. X-ray structural analysis established that Fig. 1 contains of discrete [CH 3 OC 6 H 4 COCH 2 PPh 3 ] + cations and OTfanions in a 1:1 ratio. An ORTEP plot ( Fig. 1) and crystal packing view (Fig. 2) show that the double tetrahedral OTf unit is formed by sharing one tetrahedral edge, and possesses approximate C 3 V symmetry. These units are held together by electrostatic forces. In the fact, the crystal of the phosphonium (I) shows a close association between the OTfand the inner sphere, with O···H distances of 3.07 (16) and 3.487 (5) Å (see Fig. 2, Table 1).
The P-C bond length [1.727 (2) Å] is shorter than the other P-C bonds and longer than the equivalent bond lengths of 1.66 Å, reported for methylenetriphenylphosphorane, which shows partial double-bond character for these two bonds.
The crystal structure is stabilized by C-H···O hydrogen bonds and further by C-H···π interactions.

Experimental
The title compound was obtained from reaction between (I) and AgOTf in dry methanol in a 1:1 molar ratio and under stirring for 12 h. The product was washed sveral times with dry diethyl ether and dried in a vacuum. Colourless plate crystals of C 27 H 24 F 3 O 5 P appeared by addition of dry diethyl ether to a chlroform solution. The crystal structure consists of discrete supplementary materials sup-2 [CH 3 OC 6 H 4 COCH 2 PPh 3 ]+, cations and OTfanions in a 1:1 ratio. The obtained crystals of (I) are highly air stable and resistant against moisture.

Refinement
All H atoms were positioned geometrically and were treated as riding, with C-H distances in the range 0.93-0.97 Å, and with U iso (H) = 1.2U eq (C) for aromatic and methylene H atoms and 1.5U eq (C) for methyl H atoms. Fig. 1. ORTEP plotting of one molecule in the asymmetric unit of the title compound (I) with the atom numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level.       (2)