Formation and Crystal Structures of Lewis Acid Adducts of Ph₃PCHP(O)Ph₂; New Neutral and Cationic Species 

Abstract

Abstract. The carbodiphosphorane C(PPh 3 ) 2 (1) is easily hydrolyzed from wet air to give the ylide Ph 3 PCHP(O)Ph 2 (2), which forms addition compounds with various Lewis acids to give neutral or cationic compounds. According to pairs of electrons at the central carbon atom and the oxygen atom, respectively, addition compounds with coordination modes A (via oxygen), B (via carbon), and C (via carbon and oxygen) were isolated either as by-products from reactions of Lewis acids with 1 (contaminated with some 2) or directly with 2. The crystal structures and the spectroscopic properties of 2 and of the addition

Syntheses and Crystal Structures of Copper and Silver Complexes with the Ylide Ph3PCHP(O)PPh2 as Ligand

“…As depicted in Figure 3 no further contacts to the Ag atoms exist; the ions and dichloromethane molecules are connected by weak hydrogen bridges; the nearest contacts are C(1)···F(1) = 3.225(8) Å and C(32)···F(2) = 3.121(8) Å. The P-O bond length has slightly elongated upon complex formation from 1.489(2) to 1.512(2) Å; this is less than found in adducts of 2 with main group Lewis acids [3] where the elongations are more pronounced. The different P-C bond lengths in 2, amounting to 1.717(3) Å (PO) and 1.688(3) Å (PPh 3 ), have both increased to 1.781(3) Å and 1.771(3) Å, respectively, upon complex formation, directed to P-C single bonds.…”

“…In recent papers we reported on addition compounds of 2 with Lewis acids A such as group 13 compounds BX 3 (X = F, I), AlBr 3 , and SnCl 2 , which exclusively coordinate at the oxygen atom to give neutral compounds of the type 2(O)ǞA; [3] an O coordination was also found with the electron deficient W(CO) 5 fragment. [4] In a preceding paper, the results of the alkylation of 2 were presented.…”

On the Alkylation of Ph3PCHP(O)Ph2: Formation and Crystal Structures of Neutral and Cationic Addition Compounds

“…However, the crystals obtained earlier from THF differ markedly in unit cell parameters and are therefore denoted as 6Ј. [6] An overview of the reaction products is depicted in Scheme 2.…”

“…[6] The four-membered ring of the Hg 2 I 6 anion in 6 shows an envelope configuration, whereas that in 6Ј obtained from THF is planar; both compounds differ in the parameters of the unit cell and the numbers of molecules Z in it (Z = 2 in 6Ј, and Z = 4 in 6). The P-O bond lengths vary between 1.479(6) Å (for 6Ј), 1.482(6) Å (for 6), and 1.488(5) Å (for 4) and are close to that of Ph 3 PO [1.483(2) Å].…”

“…All compounds, including starting compound 1, were structurally elucidated by X-ray analyses. [6] Subsequently, addition compound [Ph 3 PCH 2 P(OBeCl 3 )Ph 2 ]·0.75CH 2 Cl 2 with the anionic Lewis acid BeCl 3 -was described. [7] As expected, Lewis acids of group 12 to group 14 elements were found to prefer associating with the electron pair at the oxygen atom of the P=O group as depicted in coordination mode I; no tautomeric compound could be isolated when Lewis acids are located at the carbon atom as in II.…”