FORMATION AND REACTIVITY OF THE EARLY METAL PHOSPHIDES AND PHOSPHINIDENES CP-ASTERISK-2ZR=PR, CP-ASTERISK-2ZR(PR)2, AND CP-ASTERISK-2ZR(PR)3

The reactions Of CP*2ZrCl2 with 2 equiv of LiPHPh led to the formation of the unstable species CP*2Zr(PHPh)2 (1), which yields CP*2Zr(PPh2) (2) on standing for 1 h and a third product CP*2Zr(PPh)3 (3) which appears after 1 week. The compound 3 is derived cleanly from mixtures of 1 and 2 by addition of excess PH2Ph. In the related reactions, CP*2ZrCI2 reacts with 2 equiv of LiPH(C6H2Me3) to give the wine-red diphosphido-species CP*2Zr(PH(C6H2Me3))2 (4). This compound converts slowly to ortho-metalation product CP*2Zr(CH2C6H2Me2PH) (5) and the species CP*2Zr(PC6H2Me3)2 (6). These reactions infer terminal phosphinidene intermediates. Such an intermediate can be intercepted via reaction of 4 with MeCN affording CP*2Zr(NCMe)2P(C6H2Me3) (7). Further evidence for the intermediacy of a phosphinidene complex is derived from the reaction Of CP*2ZrCI2 and LiPH(C6H2Me3) in DME where the species CP*2Zr(P(C6H2Me3))(Cl)Li(DME) (8) is observed. A bent terminal phosphinidene derivative CP2Zr(P(C6H2t-BU3))(PMe3) (9) (Zr=PR, 2.505(4) angstrom) is isolated from the reaction Of CP2ZrCl2 with Li(PH(C6H2t-BU3)) in the presence of PMe3. While the phosphinidene intermediate affords the novel phosphametallocycle 7, the species 5, 6, and 3 also act as synthons for unprecedented phospha-, diphospha-, and triphosphametallocycles. Compound 5 reacts with MeCN and benzaldehyde to effect insertion of the organic reagents into the Zr-P bonds yielding the phosphametallocycles CP*2Zr(CH2C6H2Me2PH(C(Me)N)) (10) and Cp*2Zr(CH2C6H2Me2PH(C(Ph)O)) (11), respectively, while similar reactions of compound 6 afford the 1,2-diphosphametallocycles CP*2Zr(NC(Me)PC6H2Me3)2 (12) and CP*2Zr(OCH(Ph)PC6H2Me3)2 (13). Compound 12 reacts with NH4Cl affording CP*2ZrCI(NC(Me)P(C6H2Me3)PH(CrH2Me3)) (14). Cleavage of the Zr-P bonds in compound 6 is effected by sequential acidolysis with HCCPh affording CP*2Zr(CCPh)(P(C6H2Me3)PH(C6H2Me3)) (15) and CP*2Zr(CCPh)2(16), while reaction of 6 with acetone gives the dienolate complex Cp*2Zr(OC(Me)CH2)2 (17) and reaction of 6 with CH2I2 affords CP*2ZrI2 (18). Compound 3 acts as synthon for new 1,2,3-triphosphametallocycles as reactions of 3 with MeCN and benzaldehyde afford CP*2Zr(NC(Me))(PPh)3 (19) and CP*2Zr(OCH(Ph))(PPh)3 (20), respectively. The chemistry of these Zr-P species offers synthetic routes to a variety of unprecedented phosphametallocycles which augurs well for metal-mediated synthesis of organophosphorus compounds. The formulations of a number of these compounds have been confirmed crystallographically. These data are summarized as follows: 6, P2(1)/n, a = 11.464(3) angstrom, b = 19.140(5) angstrom, c = 16.165(5) angstrom, beta = 90.93(3)-degrees, V = 3546(3) angstrom3, Z = 4; 9, P2(1)/c, a = 15.011(5) angstrom, b = 9.824(5) angstrom, c = 21.745(5) angstrom, beta = 103.21(3)-degrees, V = 3122(2) angstrom3, Z = 4; 11, P2(1)/c, a = 19.352(6) angstrom, b = 10.444(8) angstrom, c = 19.647(12) angstrom, beta = 109.20(3)-degrees, V = 3750(4) angstrom3, Z = 4; 13, P2(1)/c, a = 21.301(7) angstrom, b = 10.478(4) angstrom, c = 25.102(7) angstrom, beta = 111.75(2)-degrees, V = 5204(3) angstrom3, Z = 4; 14, P2(1)/n, a = 14.731(11) angstrom, b = 17.401(5) angstrom, c = 17.143(9) angstrom, beta = 113.83(5)-degrees, V = 4020(4) angstrom3, Z = 4; 15, P2(1)2(1)2(1), a = 14.572(10) angstrom, b = 28.618(12) angstrom, c = 11.084(6) angstrom, V = 4622(4) angstrom3, Z = 4; 19, P1BAR, a = 12.634(4) angstrom, b = 17.690(4) angstrom, c = 10.169(4) angstrom, alpha = 103.43(2)-degrees, beta = 113.66(2)-degrees, gamma = 82.00(2)-degrees, V = 2022(1) angstrom3, Z = 2.