Organometallic complexes of multianionic phosphazenates

The amino-substituted phosphazene P3N3(NHCy)(6) 1 reacts as a multiprotic a cid undergoing full deprotonation in the presence of Me3Al and Et2Zn, respe ctively, which results in the formation of multinuclear metal phosphazenate s: Trimethyl aluminium deprotonates 1 with evolution of six equivalents of methane to give the pentanuclear organoaluminium complex [(thfMeAl)(Me2Al)( 4){P3N3(NCy)(6)}] 2. Diethylzinc deprotonates 1 yielding the hexanuclear zi nc complex [(EtZn)(6){P3N3(NCy)(6)}] 3. The higher homologue P4N4(NHCy)(8) 4 reacts with diethylzinc undergoing sixfold deprotonation giving the hexan uclear complex [(Etzn)(6){P4N4(NHCy)(2)(NCy)(6)}] 5, where two NH functions remain protonated. All three metal complexes 2, 3 and 5 are soluble in apr otic organic solvents. The highly charged phosphazenate ligands contain thr ee and four PN4 tetrahedra which are fused in a corner-sharing manner formi ng P3N3 and P4N4 ring structures, respectively. These are isoelectronic wit h meta-silicate anions, but in addition equiped with organic groups at term inally arranged N atoms. Both phosphazenate ligands contain various coordin ation sites and show a high flexibility of their central P-N ring conformat ion toward the complexed organometallic framework.