No abstract

Triphenylbismuth dicrotonate Ph 3 Bi(O 2 CCH=CHCH 3 ) 2 in benzene solution in the presence of 2-methyl-2-nitrosopropane decomposes in light. The phenyl radicals formed as the result of Ph 3 Bi(O 2 CCH=CHCH 3 ) 2 decomposition are confirmed by the spin-trapping method; they can initiate the methylmethacrylate polymerization at room temperature. In the absence of light the decomposition has not been observed.Кeywords: electron paramagnetic resonance, triphenylbismuth dicrotonate, 2-methyl-2nitrosopropane.

The asymmetric unit of the title compound, [Sb(C6H5)3(C10H9O3)2]·C6H6, contains one organometallic mol­ecule and one benzene mol­ecule that is disordered over two sets of sites with an occupancy ratio of 0.556 (15):0.444 (15). The SbV atom is in a distorted trigonal–bipyramidal environment with the carboxyl­ate O atoms in axial positions and phenyl C atoms in the equatorial plane. As a result of additional Sb⋯O inter­actions, one of the C—Sb—C angles is widened to 140.19 (6)°.

The molecular structure and charge density distribution in the crystals of triphenylantimony bis[(2E)-3-phenylprop-2-enoate] [Ph 3 Sb(O 2 CCH=CHPh) 2 ] and triphenylantimony bis[(2E)-3-(3-nitrophenyl)prop-2-enoate] benzene solvate [Ph 3 Sb(O 2 CCH=CHC 6 H 4 NO 2 -m) 2 ÁC 6 H 6 ]derived from the high-resolution single-crystal X-ray diffraction data at 100 K are reported together with DFT calculations of these molecules. The nature of the chemical bonds and delocalization of electron density in carboxylate ligands was investigated. The intramolecular SbÁÁÁO interactions as well as intermolecular pÁÁÁp, HÁÁÁp and OÁÁÁp ones and their energy are discussed.

The newly synthesized triphenylbismuth bis(3-phenylprop-2-enoate) was studied by X-ray diffraction and by IR, UV, and NMR spectroscopy. The crystals are monoclinic, sp. gr. C2/c, Z = 4, a = 13.2820(4) Å, b = 21.3750(2) Å, c = 12.2407(2) Å, β = 119.936(1)°. The coordination polyhedron of the bismuth atom can be described as a distorted pentagonal bipyramid.

In the present research, the heat capacities of triphenylbismuth dimethacrylate Ph3Bi­(O2CCMeCH2)2 were measured between T = 5.3 and 330 K with the precision adiabatic vacuum calorimeter and from T = 310 to 420 K with the differential scanning calorimeter. There revealed a reproducible anomaly from 150 to 170 K caused by structural changes in the crystal lattice, and intensive exothermic transition over the range from T = 385 to 420 K caused by the reductive decomposition with the polymerization of the sample under study. The experimental results were used to calculate the standard (p = 0.1 MPa) thermodynamic functions (heat capacity C p,m o, enthalpy H m o(T) – H m o(0), entropy S m o(T), and Gibbs energy Φm o(T) of crystalline triphenylbismuth dimethacrylate from T → 0 to 385 K. The standard entropy of formation at T = 298.15 K was calculated for the compound under study in the crystalline state. Obtained for Ph3Bi­(O2CCMeCH2)2 results were compared with ones for Ph3Sb­(O2CCMeCH2)2.

No abstract

Decomposition of triphenylbismuth dicrotonate in diffused light in bensene in the presence of spin trap of C-phenyl-N-tert-butylnitrone leads to formation of phenyl radicals which are registered as the adduct PhCH(Ph)N(O•)Bu-t.Triphenylbismuth dicrotonate Ph3Bi(O2CCH=CHCH3)2 in benzene solition in the presence of C-phenyl-N-tert-butylnitrone PhCH=N(O)Bu-t decomposes in light. An adduct of phenyl radical and spin trap PhCH(Ph)N(O•)Bu-t was registered by ESR method.