Tri- and tetraphenylantimony propiolates: Syntheses and structures
摘要:
The reaction of triphenylantimony with propiolic acid in the presence of hydrogen peroxide (molar ratios 1 : 2 : 1 and 1 : 1 : 1) in diethyl ether affords triphenylantimony dipropiolate Ph3Sb[OC(O)Ca parts per thousand CH](2) (I) and mu(2)-oxobis[(propiolato)triphenylantimony] [Ph3SbOC(O)Ca parts per thousand CH](2)O (II). Tetraphenylantimony propiolate Ph4SbOC(O)Ca parts per thousand CH (III) is synthesized from pentaphenylantimony and propiolic or acetylenedicarboxylic acid in toluene. According to the X-ray diffraction data, the crystals of compounds I and III include two types of crystallographically independent molecules (a and b). The antimony atoms in molecules Ia, Ib, II, IIIa, and IIIb have the trigonal-bipyramidal coordination mode with different degrees of distortion. The OSbO and OSbC axial angles are 176.8(2)A degrees (Ia, Ib), 170.17(15)A degrees, 178.78(14)A degrees (II), and 173.2(5)A degrees, 174.4(5)A degrees (IIIa, IIIb). The CSbC equatorial angles lie in the ranges 108.2(3)A degrees aEuro"143.1(3)A degrees (I), 109.0(2)A degrees aEuro"131.0(2)A degrees (II), and 113.1(4)A degrees aEuro"125.4(4)A degrees (III). The SbOSb angle in II is 141.55(19)A degrees. The Sb-C bond lengths are 2.103(8)-2.141(5) (I), 2.105(5)-2.119(5) (II), and 2.076(12)-2.166(13) (III). The Sb-O distances increase in a series of I, II, and III: 2.139(6)-2.156(7) (Ia, Ib); 2.206(4), 2.218(3) (II); and 2.338(10), 2.340(10) (III).