2-Thienylcarbonylmethylene–triphenylphosphorane ylide

In the molecule of the title compound, (2-thienylcarbonyl)(triphenylphosphonio)methanide, C24H19OPS, the geometry around the P atom is nearly tetrahedral and the O—C—C—P torsion angle is 2.80 (3)°. The thiophene ring is twisted through an angle of 4.33 (4)° with respect to the plane of the carbonyl group. Inter- and intramolecular hydrogen bonds and C—H⋯π interactions are present in the crystal structure.

In the molecule of the title compound, (2-thienylcarbonyl)-(triphenylphosphonio)methanide, C 24 H 19 OPS, the geometry around the P atom is nearly tetrahedral and the O-C-C-P torsion angle is 2.80 (3) . The thiophene ring is twisted through an angle of 4.33 (4) with respect to the plane of the carbonyl group. Inter-and intramolecular hydrogen bonds and C-HÁ Á Á interactions are present in the crystal structure.

Comment
Phosphoranes of the type (C 6 H 5 ) 3 PCHCOC 4 H 3 S (TPPY) can coordinate to metals through either C or O atoms. The crystal and molecular structure of this ylide was determined successfully. The structural investigation with metrical parameters for the title compound, (I), show that how they vary with a change in delocalization in the metal derivatives as well as in other resonance stabilized ylides. In this molecule, the bond lengths and angles (Table 1) are generally within normal ranges (Allen et al., 1987).
The P1-C6 bond length [1.727 (2) Å], is shorter than the other P-C bonds (Table 1) and longer than the equivalent bond lengths of 1.66 Å reported for methylenetriphenylphosphorane (Bart, 1969), which shows partial double-bond character for these two bonds.
The thiophenyl group is twisted with respect to the plane containing the carbonyl group through angles of 4.33 (4)°.
Bond angle of 118.30 (16)° for P1-C6-C5, indicate a distorted trigonal arrangement about C6. The non-bonded distances P1-O1 of 2.990 (3) Å of TPPY is significantly shorter than the sum of the van der Waals radii of P and O (3.3 Å) (Dunitz, 1979), indicating a strong intramolecular interaction between P + and O − charge centers, which leads to the cis orientation.

Experimental
The title compound was prepared by addition of 2-bromo-acetothiophen (0.102 g, 0.5 mmol) in chloroform (25 ml) to a solution of triphenylphosphine (0.131 g, 0.5 mmol) in the same solvent (5 ml). The resulting pale pink solution was stirred for 12 h. The solution was concentrated under reduced pressure to 5 ml, and diethyl ether (20 ml) was added. The yellow solid formed was filtered off, washed with petroleum diethyl ether (10 ml), and dried under reduced pressure. In order to get the final product, all of the crude solid was transferred to an alkaline solution of 5% NaOH and stirred at 310 K for about 14 h, yielding the white precipitate. The product was washed several times with distilled water and air dried. The resulting solid was recrystallized from a chloroform-diethyl ether mixture (m.p. 496-498 K). Yield: 78%, 0.301 g.
supplementary materials sup-2 Refinement H atoms were positioned geometrically, with C-H=0.93 Å for aromatic and methine H and constrained to ride on their parent atoms with U iso (H)=1.2U eq (C). Fig. 1. The molecular structure with the atom-numbering scheme. Displacement ellipsoids are drawn at 30% probability level.  (2-Thienylcarbonyl)(triphenylphosphonio)methanide