Oxidative additions of P-H bonds to ''zirconocene' have been studied. The resulting zirconocene-phosphide-hydrides are not stable and react further to give a variety of products the nature of which depends on the electronic and steric properties of the phosphide moiety. In the case of the PhPH2 derivative, cyclopentadienyl C-H activation occurs affording the fulvalenide-phosphide dimer [CpZr(mu-PHPh)]2(mu-eta5-eta5-C10H8) (1) in the similar reaction of CyPH2, the isolated product is [CP2Zr(mu-PHCy)]2(2). The isolated derivative of (2,4,6-Me3C6H2)-PH2 resembles 1 and was confirmed crystallographically to be [CpZr(mu-PH(2,4,6-Me3C6H2)]2-(mu-eta5-eta5-C10H8) (3). The compound 3 crystallizes in the space group P1BAR with a = 12.037(8) angstrom, b = 14.699(8) angstrom, c = 10.514(5) angstrom, a = 103.79(5)-degrees, beta = 108.87(5)-degrees, gamma = 101.89(6)-degrees, Z = 2, and V = 1626(2) angstrom3. In the case of Ph3SiPH2 three products were obtained. [CP2Zr(mu-PH(SiPh3)]2 (4) and [CpZr(mu-PH(SiPh3))]2(mu-eta5-eta5-C10H8) (5) are the major products, while [CpZr]2(mu-PH-(SiPh3)(mu-PSiPh3)(mu-eta5-eta5-C10H8) (6) is also formed in low yield. The compound 4.THF crystallizes in the space group P2(1)/n with a = 11.653(15) angstrom, b = 14.355(6) angstrom, c = 16.958(9) angstrom, beta = 93.74(8)-degrees, Z = 4, and V = 2830(6) angstrom3, While 5 crystallizes in the space group C2/c with a 15.155(6) angstrom, b = 17.304(8) angstrom, c = 17.822(7) angstrom, beta = 93.79(3)-degrees, Z = 4, and V = 4663(3) angstrom3. The phosphide-phosphinidene-bridged, mixed-valent Zr(IV)/Zr(III) compound 6.[(THF)2Li(mu-Cl)]2.THF crystallizes in the space group P1BAR with a = 11.063(7) angstrom, b = 30.112(24) angstrom, c = 10.874(8) angstrom, a = 96.21(7)-degrees, beta = 119.10(5)-degrees, gamma = 84.21(7)-degrees, Z = 2, and V = 3142(9) angstrom3. The course of these reactions is discussed in terms of the electronic and steric properties of the phosphines. The mechanism for cyclopentadienyl C-H activation is considered, and a dimeric Zr(IV) intermediate [CpZr-(mu-eta5-eta1-Cr5H4)(PHR)]2 is proposed on the basis of spectroscopic data derived from monitoring these reactions. Alternative synthetic routes to these dimers were explored. The dimers 2 and 4 were obtained from the reactions of zirconocene dichloride with Mg in the presence of the respective-phosphine. These dimers 2 and 4 were also isolated from the reaction of the primary phosphine with zirconocene-hydride chloride. The compound [CP2Zr(mu-PHPh)]2(7) was isolated in a similar reaction. The species 7 crystallizes in the space group C2/c with a = 30.083(13) angstrom, b = 9.175(6) angstrom, c = 21.292(9) angstrom, beta = 111.35(3)-degrees, Z = 8 and V = 5473(9) angstrom3. Direct reaction of Li2PPh and CP2ZrCl2 or deprotonation of 2 generates the bis(phosphinidene)-bridged homo-bimetallics [CP2Zr(mu-PR)]22- (R = Ph, 8a, R = Cy, 8b). Reaction of 8a with a proton source and TMEDA affords the mono(phosphinidene)-bridged complex [(CP2Zr)2(mu-PHPh)(mu-PPh)]-[(THF)2Li(TMEDA)] (9). The compound 9.THF crystallizes in the space group P1BAR with a = 13.520(5) angstrom, b = 18.313(7) angstrom, c = 11.411(4) angstrom, alpha = 99.27(3)-degrees, beta = 105.43(3)-degrees gamma = 98.89(3)-degrees, Z = 2, and V = 2630(2) angstrom3. Similarly, reaction of 8a with Me3O+ generates the species [Cp2-Zr)2(mu-PMePh)(mu-PPh)]Li (10). The heterobimetallic complex CP2Zr(mu-PHCy)(mu-eta1-eta2-OC)-Mo(CO)Cp (11) is derived from the reaction of 2 with [CPMO(CO)3]2. This product crystallizes in the space group P1BAR with a = 14.425(4) angstrom, b = 16.871(4) angstrom, c = 10.411(4) angstrom, alpha = 102.24(4)-degrees, beta = 104.14(2)-degrees, gamma = 65.44(2)-degrees, Z = 2, and V = 2217(1) angstrom3. Deprotonation of 11 affords the phosphinidene-bridged heterobimetallic [Cp2Zr(mu-PCy)(mu-eta1-eta2-OC)Mo(CO)Cp]- (12). This process is reversible. The chemistry and structural data for these phosphide and phosphinidene species are presented and discussed. In particular, the structural data for the Zr(III) species are considered in light of recent postulates of ''super-long' metal-metal bonding in related zirconocene dimers. Some of the discussion is supported by the results of Fenske-Hall and extended Huckel molecular orbital calculations.
