TRANSITION-METAL STANNYL COMPLEXES .9. SU BSTITUTION-REACTIONS OF THEANIONIC HYDRIDO COMPLEXES [(PI-MEC(5)H(4))-(CO)(2)MNH](-) AND [(PI-ARENE)(CO)(2)CRH](-)

The anionic hydride complexes K[(pi-MeC(5)H(4))(Co)(2)MnH] (2c) and K[ (pi-arene)(CO)(2)CrH] (pi-arene=C6H6 C(6)H(5)Me, 1,2,3-C(6)H(3)Me(3), C(6)Me(6), C(6)H(5)Ph, indan) (5a-f) are spontaneously formed on stirr ing THF solutions of the dianionic complexes K2[(pi-MeC(5)H(4),)(CO)(2 )Mn] (1) or K-2[(pi-arene)(CO)(2)Cr] (4) at -78 degrees C. The dianion ic complexes are obtained by potassium naphthalenide reduction of (pi- MeC(5)H(4))(CO)(2)MnL or (pi-arene)(CO)(2)CrL (L = pyridine or THF). R eaction of 2c with Me(3)SnCl or Ph(2)SnCl(2) yields the bis(stannyl) c omplexes Cp'(CO)(2)Mn(SnR(3))(2) (SnR(3) = SnMe(3), SnPh(2)Cl), while reactions with the ''smaller'' stannanes Me(2)SnCl(2) or Et(2)SnCl(2) results in the SnR(2)-bridged complexes [Cp'(C0)(2)Mn]2(mu-snR(2),)(Mn -Mn). The bis(stannyl) complexes (pi-arene)(CO)(2)Cr(SnR(2)C1)2 (R = M e, Ph) are obtained from 5 and R(2)SnCl(2). However, the reaction is s trongly influenced by steric effects: with Me(2)SnCl(2), bis(stannyl) complexes are obtained for pi-arene = C6H6, C(6)H(5)Me, 1,2,3-C(6)H(3) Me(3), or C(6)Me(6), with Ph(2)SnCl(2) only for pi-arene = C6H6 and CG H,Me. Reaction of the sterically demanding complexes K[(pi-C(6)H(5)Ph) (Co)(2)CrH] or K[(pi-indan)(CO)2CrH] with Ph(2)SnCl(2), stops at the s tage of the anionic stannyl complexes K[(pi-arene)(CO)(2)Cr-SnPh(2)Cl] .