SYNTHESIS AND CRYSTAL-STRUCTURE OF A NOVEL MANGANESE(III)-MOLYBDENUM(IV) HETEROOCTAMETALLIC CLUSTER, NA2MN2[MO3O4(O(2)CET)(8)](2)

A mixture of Na2MoO4 . 2H(2)O, Mo(CO)(6), Mn(CH3CO2)(3) . 2H(2)O and ( EtCO)(2)O was heated at 120 degrees C to produce the novel manganese(I II)-molybdenum(IV) hetero-octanuclear cluster Na2Mn2[Mo3O4(O(2)CEt)(8) ](2) (1) as green-black crystals in ca 15% yield. The X-ray structure determination reveals the presence of the two incomplete cubane-type c luster units, [Mo3O4(O(2)CEt)(8)](4-) bridged by two Mn-III ions. The centrosymmetric octanuclear dianions are linked by Nai into infinite c hains, It is surprising that each Mn-III ion has a rather octahedral c oordination sphere with O-Mn-O angles within 5 degrees of the expected octahedral value and six similar Mn-O bond lengths [1.963(4)-2.001(5) Angstrom], showing little Jahn-Teller distortion. Copyright (C) 1997 Elsevier Science Ltd.