TRIPODAL AMIDO LIGANDS CONTAINING AN ACTIVE LIGAND PERIPHERY

The trifunctional trisilylmethane-derived amine HC{SiMe(2)NH(2-FC6H4)} (3) (1) has been prepared which contains fluorine atoms in the ligand periphery which may act as additional donor functions in its amido com plex derivatives. Lithiation with n-BuLi and reaction with YCl3 yields the seven-coordinate yttrium complex HC{SiMe(2)N(2-FC6H4)}Y-3(OEt(2)) (3) which has been structurally characterized by X-ray crystallograph y: triclinic, P ($) over bar 1 (No. 2), alpha = 9.4244(2) Angstrom, b = 10.5951(3) Angstrom, c = 16.6929 Angstrom, alpha = 93.280(8)degrees, beta = 91.918(7)degrees, gamma = 93.465(8)degrees, Z = 2, V = 1659.9( 1) Angstrom(3), and R = 0.062. AU three fluorine donor atoms are coord inated to the yttrium center ((1)J(Y-89-F-19) = 5,3 Hz at 295 K). Rapi d dynamic processes in solution which cannot be frozen out at 180 K co nfer an effective 3-fold symmetry upon the molecule at ambient tempera ture. Reaction of lithiated 1 with ZrCl4 in diethyl ether yields the ( mu-Cl)(2)-bridged complex HC{SiMe(2)N(2-FC6H4)}3ZrCl2Li(OEt(2))(2) (4) which has one peripheral F-atom weakly coordinated to the Zr-center a s established analytically and by an X-ray structure analysis: monocli nic, P2(1)/alpha (No. 14), alpha = 13.4123(2) Angstrom, b = 18.0086(3) Angstrom, c 17.3750(3) Angstrom, beta = 90.391(7)degrees, Z = 4, V = 4196.6(2) Angstrom(3), and R = 0.048, Reaction of 4 with MeLi gives th e methyl-zirconium compound HC{SiMe(2)N(2-FC6H4)}3ZrCH3 (5) while upon condensation with [CpFe(CO)(2)](-), the dinuclear Zr-Fe-bonded comple x HC{SiMe(2)N(2-FC6H4)}3ZrFe(CO)(2)Cp (6) is obtained. The spectroscop ic data and structural considerations indicate that in 5 all three F-d onors are bonded to Zr whereas in 6 all are uncoordinated, demonstatin g the coordinative flexibility of the ancillary donor functions in the tripodal amido complexes derived from 1.