AB INITIO CALCULATION OF CAGE-LIKE SILOXANES AND METALLOSILOXANE STRUCTURE FORMATION

Several ab initio (DFT-B3PW91/6-31g(d,p)) calculations of cage-like siloxanes (MeSiO1.5)n (n = 4-12) have been made. It was shown that cubane-like structure (MeSiO1.5)8 is the most stable one. Refined mechanism of polymeric metallasiloxanes cleavage by the silanolates has been suggested. It has been shown that isomerisation of Cu-containing siloxanes (rearrangement of sandwich-like form into globule-like form) is mostly governed by the coordination properties of solvates.

cage-like siloxanes, cage-like metallasiloxanes, formation enthalpy, ab initio calculations.

1. Kudo T., Gordon M.S. theoretical studies of the mechanism for the synthesis of silsesquioxanes // J. Phys. Chem. A. 2000. V. 104. P. 4058-4063.

2. Xiang K.-H., Pandey R., Pernicz U.C., Freeman C. Theoretical study of structural and electronic properties of H-silsesquioxanes // J. Phys. Chem. B. 1998. V. 102. Р. 8704-8711.

3. Rikowski E., Marsmann H.C. Cage-rearrangement of silsesquioxanes // Polyhedron. 1997. V. 16. P. 3357-3361.

4. Wichmann D., Jug K. MSINDO study of hydridosilsesquioxanes // J. Phys. Chem. B. 1999. V. 103. P. 10087-10091.

5. Jug K., Wichmann D. MSINDO study of large silsesquioxanes // J. Comput. Chem. 2000. V. 16. P. 1549-1553.

6. Endo M., Kroto H.W. Formation of carbon nanofibers // J. Phys. Chem. 1992. V. 96. P. 6941-6944.

7. Jug K., Gloriozovy I.P. Mechanism of silsesquioxane growth // Phys. Chem. Chem. Phys. 2002. V. 4. Р. 1062-1066.

8. Sydora O.L., Wolczanski P.T., Lobkovsky E.B., Buda C., Cundari Th.R. Low-coordinate chromium siloxides. The “box” [Cr(μ-Cl)(μ-OSitBu3)]4, distorted trigonal [(tBu3SiO)3Cr][Na(benzene)] and [(tBu3SiO)3Cr][Na(dibenzo-18-c-6)], and trigonal (tBu3SiO)3Cr // Inorg. Chem. 2005. V. 44. P. 2606-2618.

9. Jacobsen H., Fink M.J. Decomposition cascades of dicoordinate copper(I) chalcogenides // Eur. J. Inorg. Chem. 2007. V. 13. Р. 5294-5299.

10. Borisov Yu.A., Papkov V.S., Sergienko N.V., Zavin B.G., Buzin M.I. Si-C bond strength in cage-like methylsilsesquioxanes and methyl-bearing metalosilsesquioxanes estimated from DFT calculations // Russ. Chem. Bull. Int. Ed. 2010. V. 59. Р. 881-885.

11. Воронков М.Г., Милешкевич В.П., Южелевский Ю.А. Силоксановая связь. - Новосибирск: Наука. Сибирское отделение, 1976. 413 c.

12. Завин Б.Г., Сергиенко Н.В., Биляченко А.Н., Черкун Н.В., Дронова М.С., Корлюков А.А., Старикова О.М., Левицкий М.М., Тимофеева Г.И. Синтез биметаллических каркасных металло-органосилоксанов из полимерных металлосилоксанов // Изв. АН. Сер. хим. 2011. № 8. С. 1621-1624.

13. Zavin B.G., Sergienko N.V., Gorodnichev E.V., Myakushev V.D., Korlyukov A.A., Antipin M.Yu. Rearrangement of the siloxane skeleton in Cu-Na-containing phenylsiloxanes // Mendeleev Commun. 2005. V. 15. Р. 245-246.

14. Rentschler E., Gatteschi D., Cornia A., Fabretti A.C., Barra A.-L., Shchegolikhina O.I., Zhdanov A.A. Molecule-based magnets: Ferro- and antiferromagnetic interactions in copper(II)−polyorgano-siloxanolate clusters // Inorg. Chem. 1996. V. 35. P. 4427-4431.