Synthesis and characterization of dimeric and square-shaped dicarboxylate-bridged dimolybdenum(II) coordination compounds

• New Mo24+ compounds with dicarboxylate-bridges and different shapes are described.
• Two of them feature a dimeric structure and one is square-shaped.
• All might be used as potential building blocks for MOFs.

The reaction of 1 equivalent of the dimolybdenum(II) complex [Mo2(NCCH3)10][BF4]4 (1) with tetrabromoterephthalic acid (0.5 equiv.) in acetonitrile or propionitrile affords the dimeric dicarboxylate-bridged complexes [(CH3CN)8Mo2(OOC-C6Br4-COO)Mo2(NCCH3)8][BF4]6 (2) and [(CH3CH2CN)8Mo2(OOC-C6Br4-COO)Mo2(NCCH2CH3)8][BF4]6 (3), respectively. The molecular square [(CH3CN)6Mo2(OOC-C4H2S-COO)]4[BF4]8 (4) can be isolated by reacting [Mo2(NCCH3)10][BF4]4 (1) (1 equiv.) with 2,5-thiophenedicarboxylic acid (1 equiv.) in acetonitrile. The isolated coordination compounds 2–4 are characterized by NMR spectroscopy (1H, 11B, 13C{1H}, 19F), IR spectroscopy, elemental analysis, TG–MS measurements and UV–Vis spectroscopy. The molecular structures of compounds 2 and 4 are determined by X-ray single crystal diffraction.

The reaction of the dinuclear compound [Mo2(NCCH3)10][BF4]4 (1) with dicarboxylic organic linkers affords dimeric and square-shaped dimolybdenum(II) coordination compounds. Accordingly, starting from the dinuclear precursor [Mo2(NCCH3)10][BF4]4 (1), larger molecules can be stepwise synthesized, which might eventually lead to MOFs.Figure optionsDownload as PowerPoint slide