Reactivity of a Phosphido-Niobocene Derivative toward CS 2 and Alkyl Halides to Give Phosphinodithioformato- and Phosphino-Niobocene Complexes: X-ray Crystal Structures of [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (K 1 -S-SC(S)(PPh 2 ))(CO)] and [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (P(I)Ph 2 )(CO)]I 3 Antonio Antin ˜olo,* Santiago Garcı ´a-Yuste, Antonio Otero,* Juan C. Pe ´rez-Flores, Rebeca Reguillo-Carmona, Ana M. Rodrı ´guez, and Elena Villasen ˜or Departamento de Quı ´mica Inorga ´ nica, Orga ´ nica y Bioquı ´mica, Facultad de Quimica, UniVersidad de Castilla-La Mancha, 13071 Ciudad Real, Spain ReceiVed NoVember 24, 2005 The reaction of the niobocene complex [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (PHPh 2 )(CO)]Cl (1) with NaOH yielded the corresponding phosphidoniobocene derivative [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (PPh 2 )(CO)] (2) by deprotonation of the P-H bond. The subsequent insertion reaction of carbon disulfide into the Nb-P bond yielded the first examples of a diphenylphosphinodithioformato ligand coordinated to the niobocene system by giving [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (κ 1 -S-SC(S)(PPh 2 ))(CO)] (3) and [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (κ 2 -S,S-SC(S)(PPh 2 ))] (4); the latter compound can also be prepared by the corresponding CO elimination of 3. The cationic d 2 species [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (PRPh 2 )(CO)]X (R ) Me, X ) I(5); CH 2 Ph, X ) Br (6); CH 2 CH 2 Ph, X ) Br (7)) were prepared by the reaction of alkyl halides RX (R ) Me, X ) I; CH 2 Ph, X ) Br; CH 2 CH 2 Ph, X ) Br) with 2 by electrophilic attack on the phosphorus atom present in the phosphido terminal ligand. In the same way, the reaction of 2 with ICH 2 CH 2 I yielded the complex [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (P(I)Ph 2 )(CO)]- I 3 (8). The molecular structures of 3 and 8 were determined by single-crystal X-ray diffraction studies. Introduction Dithiocarbamato ligands, R 2 NCS 2 - , have attracted consider- able attention in coordination chemistry, 1 mainly due to their ability to form stable chelate complexes. However, very little effort has been directed toward investigating the analogous dialkylphosphinodithioformato ligands, R 2 PCS 2 - . Indeed, only a few well-characterized R 2 PCS 2 - -containing complexes of early-middle transition metals such as Zr, 2 Mo, 3 and W 4,5 have been reported to date, and in these complexes, the ligand coordinates to metal centers through the two S atoms 2 (a), the P and S atoms by chelation 5a (b), and either simple S- or P-coordination 5b (c and d) (see Figure 1). A few years ago, we reported the synthesis of a new family of complexes including [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (PHPh 2 )L]Cl (1), where L ) CO, CNR, 6 and these were prepared by an insertion reaction of ClPPh 2 into the Nb-H bond of [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 - (H)L)]. Treatment of derivative 1 with aqueous NaOH yielded the corresponding neutral phosphidoniobocene complex [Nb- (η 5 -C 5 H 4 SiMe 3 ) 2 (PPh 2 )(CO)] (2) by deprotonation of the P-H bond. 7 This complex represents an interesting starting material to extend the phosphorus-containing niobocene chemistry. The phosphorus atom from the phosphido terminal ligand has a lone electron pair that is expected to give rise to interesting chemistry that can be explored. We focused our attention on the synthesis of new phosphorus-containing niobocene complexes from 2 by exploring the possibilities for both the insertion reaction into the Nb-P bond, using carbon disulfide as the reagent, and the electrophilic attack on the P atom of the phosphido terminal ligand in alkylation processes with several RX reagents. The first type of reactivity has allowed the preparation of the new niobocene containing the anionic diphenylphosphinodithiofor- mato ligand, Ph 2 PCS 2 - , namely, [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (κ 1 -S-SC- (S)(PPh 2 ))(CO)] (3) and [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (κ 2 -S-SC(S)- (PPh 2 ))] (4), and the second one, the isolation of a new family of cationic d 2 18-electron complexes [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 - (PRPh 2 )(CO)]X (R ) Me, X ) I(5); CH 2 Ph, X ) Br (6); CH 2 - CH 2 Ph, X ) Br (7)). Finally, the reaction of 2 in the presence of ICH 2 CH 2 I gave [Nb(η 5 -C 5 H 4 SiMe 3 ) 2 (P(I)Ph 2 )(CO)]I 3 (8). * To whom correspondence should be addressed. E-mail: antonio.antinolo@uclm.es; antonio.otero@uclm.es. Fax: +34926295318. (1) (a) Coucouvanis, D. Progr. Inorg. Chem. 1979, 26, 301. (b) Coucouvanis, D. Progr. Inorg. Chem. 1970, 11, 233. (c) Cras, J. A.; Willemse, J. In ComprehensiVe Coordination Chemistry; Wilkinson, G., Gillard, R. D., McCleverty, J. A., Eds.; Pergamon Press: Oxford, 1987; Vol. 2, p 579. (d) Stucher, D.; Patterson, D.; Mayne, C. L.; Orendt, A. M.; Grant, D. M.; Parry, R. W. Inorg. Chem. 2001, 40, 1902, and references therein. (2) Hey-Hawkins, E.; Lappert, M. F.; Atwood, J. L.; Boot, S. G. J. Chem. Soc., Chem. Commun. 1987, 421. (3) Davies, J. E.; Feeder, N.; Mays, M. J.; Tompkin, P. K.; Woods, A. D. Organometallics 2000, 19, 984. (4) Sanchez-Pelaez, A. E.; Perpin ˜ an, M. F.; Gutierrez-Puebla, E.; Monge, A.; Ruiz-Valero, C. J. Organomet. Chem. 1990, 384, 79. (5) (a) Yih, K.-H.; Lin, Y.-C.; Cheng, M.-C.; Wang, Y. J. Chem. Soc., Dalton Trans. 1995, 1305. (b) Yih, K.-H.; Lin, Y.-C.; Cheng, M.-C.; Wang, J. Chem. Soc., Chem. Commun. 1993, 1380. (6) Antin ˜olo, A.; Carrillo-Hermosilla, F.; Fernandez-Baeza, J.; Garcı ´a- Yuste, S.; Otero, A.; Sa ´nchez-Prada, J.; Villasen ˜ or, E. Eur. J. Inorg. Chem. 2000, 1437. (7) (a) Bonnet, G.; Lavastre, O. J. C.; Moise, C. New J. Chem. 1988, 12, 551. (b) Oudet, P.; Kubicki, M. M.; Moise, C. Organometallics 1994, 13, 4278. (c) Oudet. P.; Perrey, D.; Bonnet, G.; Moise, C.; Kubicki, M. M. Inorg. Chim. Acta 1995, 273, 79. (d) Challet, S.; Leblanc, J. C.; Moise, C. New J. Chem. 1993, 17, 251. 1310 Organometallics 2006, 25, 1310-1316 10.1021/om051013u CCC: $33.50 © 2006 American Chemical Society Publication on Web 02/02/2006