ZIRCONIUM CLUSTERS FROM THE REACTION OF ZRCL4 WITH HSNBU(3) FOLLOWED BY ADDITION OF PHOSPHINES - ZR6CL14H4(PR(3))(4) COMPOUNDS

The reduction of ZrCl4 with HSnBu(3) followed by addition of phosphine s yields pentanuclear cluster compounds ZT(5)Cl(12)(PR(3))(5)H-4 (2) a nd three types of hexanuclear cluster compounds, ZT(6)Cl(14)(PR(3))(4) H-4 (3), as well as [Zr6Cl18H5](3-) (4) and a small amount of [Zr6Cl18 H4](4-) (5) Separation of these compounds has been achieved by using d ifferent solvents in which they have different solubilities and stabil ities. The presence of hydrogen atoms and their numbers have been esta blished by 1(H) NMR spectroscopy. The compounds ZT(6)Cl(14)(PR(3))(4)H -4 (3a, R = Me; 3b, R = Et; 3c, R = n-Pr) and [HP(t-Bu)(2)Ph](3)[Zr6Cl 18H5] (4d) have been characterized by X-ray crystallography. In compou nds 3a and 3b, four hydrogen atoms distributed on the eight triangular faces of the Zr-6 octahedron were located. Compound 3a . 2CH(2)Cl(2) crystallized in the monoclinic space group P2(1)/n with cell dimension s (-75 degrees C) of a 11.149(2) Angstrom, b = 11.049(4) Angstrom, c = 20.666(7) Angstrom, beta = 103.42(2)degrees, V = 2476(1) Angstrom(3), and Z = 2. Compound 3b . 2CH(2)Cl(2) crystallized in orthorhombic spa ce group Pbca with cell dimensions (-60 degrees C) of a = 12.127(3) An gstrom, b = 21.793(5) Angstrom, c = 23.022(4) Angstrom, V = 6084(2) An gstrom(3), and Z = 4. Compound 3c . 2.31C(6)H(6) crystallized in tricl inic space group <P(1)over bar> with cell dimensions (-60 degrees C) o f a = 12.585(1) Angstrom, b = 13.679(2) Angstrom, c = 23.319(4) Angstr om, alpha = 97.08(2)degrees, beta = 94.77(2)degrees, gamma = 93.30(2)d egrees, V = 3960.6(9) Angstrom(3), and Z = 2. Compound 4d . 2CH(2)Cl(2 ) . 2C(6)H(6) crystallized in monoclinic space group C2/c with cell di mensions (-60 degrees C) of a = 29.432(4) Angstrom, b = 13.503(1) Angs trom, c = 23.892(3) Angstrom, beta = 110.96(1)degrees, V = 8867(2) Ang strom(3), and Z = 4. In compounds 3a-c, six zirconium atoms are arrang ed in a slightly elongated octahedron with four phosphine ligands at t he equatorial positions. The distance of Zr,Zr, Zr-ax(3.359(8) Angstro m) is slightly longer that of Zr-eq-Zr-eq (3.308(6) Angstrom), but bot h of them are shorter than that found in compound 4d (3.416(2) Angstro m).