SYNTHESIS AND GAS-OCCLUSION PROPERTIES OF DINUCLEAR MOLYBDENUM(II) DICARBOXYLATES (FUMARATE, TEREPHTHALATE, TRANS-TRANS-MUCONATE, PYRIDINE-2,5-DICARBOXYLATE, AND TRANS-1,4-CYCLOHEXANEDICARBOXYLATE)

lThe bis-mu-dicarboxylate molybdenum(II) complexes Mo(II)(2)L-2 (L = t rans-O2C-CH=CH-CO2 (1), p-O2C-C6H4-CO2 (2), trans-trans-O2C-CH=CH-CH=C H-CO2 (3), 2,5-O2C-C5H3N-CO2 (4), and trans-O2C-C6H10-CO2 (5)) were pr epared and their gas-occlusion properties were characterized. The dinu clear complexes have quadruple Mo-Mo bonds, with the ground electronic configuration (sigma)(2)(pi)(4)(delta)(2). All of these complexes are capable of occluding a large amount of gas (1 or 2 mol of N-2 gas per 1 mol of molybdenum atoms). Investigation of the structures of these complexes indicates that gases are most probably occluded in homogeneo us and linear micropores which are composed of micropore units surroun ded by four dicarboxylate bridges. C-13-CP/MAS NMR measurements indica te that gas molecules are held in the micropores created by the dicarb oxylate ligands. (C) 1998 Elsevier Science S.A. All rights reserved.