Synthesis, structure, and reactivity of [Zr6Cl18H5](2-), the first paramagnetic species of its class

Reaction of [Zr6Cl18H5](3-) (1) With 1 equiv of TiCl4 yields a new cluster anion, [Zr6Cl18H5](2-) (2), which can be converted back into [Zr6Cl18H5](3-) (1) upon addition of 1 equiv of Na/Hg. Cluster 2 is paramagnetic and unstable in the presence of donor molecules. It undergoes a disproportionation reaction to form 1, some Zr(IV) compounds, and H-2. It also reacts with TiCl4 to form [Zr2Cl9](-) (4) and a tetranuclear mixed-metal species, [Zr2Ti2Cl16](2-) (3). The oxidation reaction of 1 with TiCl4 is unique. Oxidation of 1 with H+ in CH2Cl2 solution results in the formation of [ZrCl6](2-) (5) and H-2, while in py solution the oxidation product is [ZrCl5(py)](-) (6). There is no reaction between 1 and Til(4), ZrCl4, [TiCl6](2-), [ZrCl6](2-), or CrCl3. Compounds [Ph(4)P](2)[Zr6Cl18H5] (2a), [Ph(4)P](2)[Zr-2-Ti2Cl16] (3a), [Ph(4)P](2)[Zr2Cl9] (4a), [Ph(4)P](2)[ZrCl6]. 4MeCN (5a . 4MeCN), and [Ph(4)P[ZrCl5(py)] (6a) were characterized by X-ray crystallography. Compound 2a crystallized in the trigonal space group R (3) over bar with cell dimensions (20 degrees C) of a = 28.546(3) Angstrom, b = 28.546(3) Angstrom, c = 27.679(2) Angstrom, V = 19533(3) Angstrom(3), and Z = 12. Compound 3a crystallized in the triclinic space group P (1) over bar with cell dimensions (-60 degrees C) of a = 11.375(3) Angstrom, b = 13.357(3) Angstrom, c = 11.336(3) Angstrom, alpha = 106.07(1)degrees, beta = 114.77(1)degrees, gamma = 88.50(1)degrees, V = 1494.8(7) Angstrom(3), and Z = 1. Compound 4a crystallized in the triclinic space group P (1) over bar with cell dimensions (-60 degrees C) of a = 12.380(5) Angstrom, b = 12.883(5) Angstrom, c = 11.000(4) Angstrom, alpha = 110.39(7)degrees, beta = 98.29(7)degrees, gamma = 73.12(4)degrees, V = 1572(1) Angstrom(3) and Z = 2. Compound 5a . 4MeCN crystallized in the monoclinic space group P2(1)/c with cell dimensions (-60 degrees C) of a 9.595(1) Angstrom, b = 19.566(3) Angstrom, c = 15.049(1) Angstrom, beta = 98.50(1)degrees, V = 2794.2(6) Angstrom(3), and Z = 2. Compound 6a crystallized in the monoclinic space group P2(1)/c with cell dimensions (20 degrees C) of a = 10.3390(7) Angstrom, b = 16.491(2)Angstrom, c = 17.654(2) Angstrom, beta = 91.542(6)degrees, V = 3026.4(5) Angstrom(3), and Z = 4.