CONTRIBUTIONS TO THE CHEMISTRY OF PHOSPHO RUS .227. HP(4)(CIRCLE-MINUS) AS A COMPLEX LIGAND - FORMATION AND PROPERTIES OF [(ETA(5)-C5H5)2ZRCL(P4H)], [(ETA(5)-C5ME5)2ZRCL(P4H)], AND [(ETA(5)-C5H5)3ZR(P4H)]

The novel complexes [(eta5-C5H5)2ZrCl(P4H)] (1), [(eta5-C5Me5)2ZrCl(P4 H)] (2), and [(eta5-C5H5)3Zr(P4H)] (3) have been obtained by reaction of a solution of (Na/K)HP, with the zirconocen derivatives [(eta5-C5H5 )2ZrCl2], [(eta5-C5Me5)2ZrCl2], and [(eta5-C5H5)3(eta1-C5H5)Zr] under suitable conditions. The structure of the compounds 1-3, which are onl y stable in solution, has been elucidated by means of P-31-NMR spectro scopy. It is highly probable that the exo endo isomer exists in each c ase. In addition, further isomers of lower relative abundancies have b een observed, in which the ligands presumably exhibit a different spat ial orientation relatively to each other.