Azide alkyne cycloaddition facilitated by hexanuclear rhenium chalcogenide cluster complexes.

Two hexanuclear rhenium clusters containing azide ligands, [Re6Se8(PEt3)5(N3)]BF4 and [Re6Se8(PEt3)4(N3)2], were synthesized from the analogous pyridine complexes and fully characterized. Studies show that [Re6Se8(PEt3)5(N3)]BF4 reacts with activated alkynes, dimethyl acetylenedicarboxylate and methyl 4-hydroxyhex-2-yneoate, to form the triazolate cluster complexes [Re6Se8(PEt3)5(L1 or L2)]BF4 (where L1 = 4,5-bis(methoxycarbonyl)-1,2,3-triazol-2-yl and L2 = 4-methoxycarbonyl-5-(1-propanol)-1,2,3-triazol-2-yl). The bis-triazolato complex, cis-[Re6Se8(PEt3)4(L1)2] was also prepared via a similar reaction starting with cis-[Re6Se8(PEt3)4(N3)2] demonstrating that these clusters can promote two azide moieties to undergo heterocyclic ring formation.

Synthesis and study of hexanuclear molybdenum clusters containing thiolate ligands.

Four hexanuclear molybdenum chloride cluster complexes containing terminal thiolate ligands have been synthesized and fully characterized. (Bu 4N) 2[Mo 6Cl 8(SEt) 6] was prepared by reacting Na 2[Mo 6Cl 8(OMe) 6] with an excess of ethanethiol in refluxing tetrahydrofuran. (PPN) 2[Mo 6Cl 8(SBu) 6], (Bu 4N) 2[Mo 6Cl 8(SBn) 6], and (Bu 4N) 2[Mo 6Cl 8(SNC 8H 6) 6] (C 8H 6NS (-) = 3-indolylthiolate) were subsequently prepared in the reaction of [Mo 6Cl 8(SEt) 6] (2-) with an excess of HSR (R = Bu, Bn or 3-indolyl).