The reaction between 1,2-B2Cl2(MMe2)(2) and disodium catecholate Na-2[1,2-O
2C6H4] affords the cyclic diborane(4) compound 1,2-B-2(NMe2)(2)(cat) (cat =
1,2-O2C6H4), whereas a similar reaction using dilithium thiocatecholate Li
-2[1,2- S2C6H4] affords the 1,1-isomer 1,1-B-2(NMe2)(2)(thiocat) (thiocat =
1,2-S2C6H4). Both compounds can be used to prepare unsymmetric diborane(4)
species.