Synthesis and Investigation of Perfluorinated Polystannanes

Two fluorinated tetraaryl stannanes, 1 and 2 were synthesized in good yields. X-ray crystallography revealed deviation from ideal tetrahedral geometry with C-Sn-C bond angles between 107.89°-112.7° for 1 and 104.69°-120.76° for 2. Dichlorides 4 and 5 were synthesized using a redistribution reaction between SnC1₄ and 1-2. These dichlorides also deviated from tetrahedral geometry with bond angles between 101.79°-128.44° for 4 and 99.23°-125.9° for 5. Polymerizaton of 4 and 5 by Wurtz coupling produced polymers 10 and 11. Absolute molecular weights in the range of 1.16 x 10⁵-2.92 x 10⁷ Da was estimated for 10 and 1.47 x 10⁵ Da for 11. UV/VIS spectroscopy gave values of 332 nm and 328 nm that are blue shifted to other polystannanes. The unexpected cleavage of a tin-aryl bond produced tin trihydrides 8 and 9. Polymerization of 8-9 produced the network polymers 12 and 13 with [wavelength]max values of 354 nm and 350 nm.

Synthesis and Investigation of Perfluorinated Polystannanes

Two fluorinated tetraaryl stannanes, 1 and 2 were synthesized in good yields. X-ray crystallography revealed deviation from ideal tetrahedral geometry with C-Sn-C bond angles between 107.89°-112.7° for 1 and 104.69°-120.76° for 2. Dichlorides 4 and 5 were synthesized using a redistribution reaction between SnC1₄ and 1-2. These dichlorides also deviated from tetrahedral geometry with bond angles between 101.79°-128.44° for 4 and 99.23°-125.9° for 5. Polymerizaton of 4 and 5 by Wurtz coupling produced polymers 10 and 11. Absolute molecular weights in the range of 1.16 x 10⁵-2.92 x 10⁷ Da was estimated for 10 and 1.47 x 10⁵ Da for 11. UV/VIS spectroscopy gave values of 332 nm and 328 nm that are blue shifted to other polystannanes. The unexpected cleavage of a tin-aryl bond produced tin trihydrides 8 and 9. Polymerization of 8-9 produced the network polymers 12 and 13 with [wavelength]max values of 354 nm and 350 nm.

Mechanism on Redistribution Synthesis of Dichlorodimethylsilane by AlCl3/ZSM-5(3T)@γ-Al2O3 Core-shell Catalyst

The redistribution method plays an important role in addressing the issue of organosilicon by-product in the direct synthesis of dichlorodimethylsilane, and the redistribution mechanism is still a topic of debate. The redistribution by ZSM-5(3T)@γ-Al2O3 core-shell catalyst and post-modified AlCl3/ZSM-5(3T)@γ-Al2O3 catalyst was technically performed using the Density Functional Theory (DFT) at the level of B3LYP/6-311++G(3df,2pd). The result shows that No.1 active site of ZSM-5(3T)@γ-Al2O3 core-shell structure has a significant effect on the activity of the catalyst. Indicating that the active center involved in the reaction is H provided by Al-O-H bond, which is an obvious catalytic active center of Bronsted acid. Furthermore, post-modified AlCl3/ZSM-5(3T)@γ-Al2O3 catalyst is in more favor of redistribution reaction comparing with ZSM-5(3T)@γ-Al2O3 core-shell catalyst. It ascribes to the robust Lewis site of aluminum chloride favorable modification.

Synthesis and Structure Features of Tetraphenylantimony 2,3-Difluoro- and 2,3,4,5,6-Pentafluorobenzoate

Tetraphenylantimony 2,3-difluorobenzoate (1) and tetraphenylantimony 2,3,4,5,6-pentafluorobenzoate (2) was obtained by the interaction of pentaphenylantimony with 2,3-difluorobenzoic and 2,3,4,5,6-pentafluorobenzoic acids in benzene with a yield of up to 98 %. The compounds were also synthesized by the ligand redistribution reaction between pentaphenylantimony and triphenylantimony dicarboxylates. The compounds have been identified by IR spectroscopy and X-ray diffraction analysis. According to the X-ray diffraction data, the antimony atoms in compounds 1 and 2 have a distorted trigonal-bipyramidal coordination with the oxygen atom in axial positions. X-ray diffraction analysis was performed on a D8 QUEST diffractometer (Bruker). The crystallographic parameters of the unit cell of the compounds: 1 space group Р1 ̅, а = 9.857(5), b = 10.154(7), c = 14.362(11) Å, α = 83.74(4)°, β = 82.59(3), γ = 68.34(2)°, V = 1321.9(16) Å3, ρcalc = 1.475 g/cm3, Z = 2; 2 space group Р21/с, а = 16.186(9), b = 8.771(6), c = 20.413(13) Å, α = 90.00°, β = 113.073(17), γ = 90.00°, V = 2666(3) Å3, ρcalc = 1.597 g/cm3, Z = 4. The OSbO axial angles are slightly different and amount to 177.90(5)º in 1 and 179.00(5)º in 2. The sums of the CSbC equatorial angles are 356.89(9)º (1), 355.85(7)º (2). The Sb–Ceq distances in compounds 1 and 2 are 2.116(2), 2.119(2), 2.118(2) and 2.1073(17), 2.1158(18), 2.1152(19) Å respectively, which are significantly shorter than the Sb–Сax bond lengths (2.169(2) and 2.1617(19) Å). The organization of molecules in the crystals of compounds is due to hydrogen bonds and CHπ-interactions of the aryl and carboxyl ligands. The main difference between structures 1 and 2 is the different Sb–O bond lengths (2.2864(18) and 2.3168(18) Å), which is due to an increase in the electronegativity of the carboxyl ligand in 2, caused by the presence of five electronegative fluorine atoms in the benzoate substituent. Complete tables of atom coordinates, bond lengths and valence angles are deposited at the Cambridge Crystallographic Data Center (No. 1980908 (1); 1977189 (2); [email protected]; http://www.ccdc.cam.ac.uk/data_request/cif).

Borohydride catalyzed redistribution reaction of hydrosilane and chlorosilane: a potential system for facile preparation of hydrochlorosilanes

A borohydride catalyzed Si–H/Si–Cl redistribution system was established to prepare hydrochlorosilanes facilely and efficiently.