REACTIVITY OF THE UNSATURATED MANGANESE DIHYDRIDES [MN-2(MU-H)(2)(CO)(6)(MU-L(2))] (L(2)=PH(2)PCH(2)PPH(2) OR (ETO)(2)POP(OET)(2)) TOWARDS SMALL MOLECULES

The unsaturated dihydrides [Mn-2(mu-H)(2)(CO)(6)(mu-L(2))] (L(2)=Ph(2) PCH(2)PPh(2), dppm, 1 or (EtO)(2)POP(OEt)(2), tedip, 2) react with car bon dioxide or formic acid to yield a mixture containing the hydridofo rmate isomers [Mn-2(mu-H)(mu-eta(2)-O2CH)(CO)(6)(mu-L(2))] (L(2)=dppm, 3a; tedip, 3b) and [Mn-2(mu-H)(mu-eta(1)-OC(O)H)(CO)(6)(mu-L(2))] (L( 2)=dppm, 4a; tedip, 4b) in equilibrium. Our previous characterization of the second complex as [Mn-2(mu-H)(mu-OH)(CO)(6)(mu-L(2))] was erron eous. In contrast, reaction of 1 with CH3COOH yields the acetate compl ex [Mn-2(mu-H)(mu eta(2)-O2CCH3)(CO)(6)(mu-dppm)] (3c) as the sole pro duct. Dihydride 1 also reacts with organic Bronsted acids such as 4-ni trophenol, tert-butylmercaptan and 4-toluenethiol yielding the corresp onding hydridoalkoxide [Mn-2(mu-H)(mu-O-4-C6H4-NO2)(CO)(6)(mu-dppm)] ( 5a), or hydridothiolates [Mn-2(mu H)(mu-SR)(CO)(6)(mu-dppm)] (R=C(CH3) (3), 6a; 4-C6H4-CH3, 6b) respectively. Related hydridoalkoxides, [Mn-2 (mu-H)(mu-OR)(CO)(6)(mu-L(2))] (L(2)=dppm; R=CH2CH3, 5c; CH2-4-C6H4CH3 , 5d; CH(CH3)(2), 5f. L(2)=tedip, R=CH2C6H5, 5e; CH(CH3)(2), 5g; CH(CH 3)CH2CH3, 5h), can be obtained in good yield by treatment of 1 or 2 wi th the appropriate aldehydes or ketones at room temperature.