TRA-P-TOLYPORPHYRINATO)SILICON(IV),(TTP)SI(OTF)(2) - THE FIRST STRUCTURALLY CHARACTERIZED (PORPHYRINATO)SILICON(IV) COMPLEX

The silicon metalloporphyrin (TTP)SiCl2 (1) (TTP = dianion of tetra-p- tolylporphyrin) has been prepared by the condensation of [Li-2(THF)(2) ][TTP] with HSiCl3 in methylene chloride at -78 degrees C. The reactio n proceeds via the apparent loss of LiCl and LiH. The compounds (TTP)S iF2 (2) and (TTP)Si(O3SCF3)(2) (3) were prepared by the reaction of 1 with SbF3 (or AgBF4) and Me(3)SiO(3)SCF(3) (or AgO3SCF3), respectively . Compound 1 is extremely water sensitive in solution, yielding [(TTP) H-4]Cl-2, yet 2 is insensitive to water. Bis(triflate) 3 is converted to (TTP)Si(OH)(2) upon exposure to water in solution and quenching wit h base. The single-crystal X-ray structure of 3 has been determined. T he silicon lies in a slightly distorted octahedral geometry with the t riflates in a trans configuration, and the porphyrin is in a ruf nonpl anar form. The structure of 3 is compared to those of other main-group metalloporphyrins. Crystallographic data for 3: orthorhombic, space g roup Pca2(1), a = 24.740(5)Angstrom, b = 11.940(2)Angstrom, c = 15.514 (3)Angstrom, alpha = beta = gamma = 90 degrees, V = 4583(2) Angstrom(3 ), Z = 4, R1 = 0.0414.