Inter-conversion of 15-MC-5 to 12-MC-4 manganese metallacrowns: structure and bioactivity of metallacrowns hosting carboxylato complexes.
Interaction of manganese with salicylhydroxamic ligands (shi) in methanol, in the presence of pyridine, leads to the formation of a series of 15-membered metallacrown (MC) Mn(II)(L)2[15-MCMn(III)N(shi)-5](py)6 or 7, (L=formato, benzoate or alkanoato ligand, py=pyridine). In the absence of pyridine, the Mn(II)(L)2[12-MCMn(III)N(shi)-4](MeOH)6 metallacrown was isolated and structurally characterized. The crystal structure of {[Mn(II)(HCOO)2][(15-MCMn(III)N(shi)-5)(py)7]}.py.1.9CH3OH.H2O (1) contains a neutral 15-membered metallacrown ring consisting of five Mn(III) and five shi(-3) ligands. The 15-membered metallacrown ring is formed by the succession of five structural moieties of the type [Mn(III)-N-O]. The diverse in the configuration (planar or propeller) for the ring Mn(III) ions gives the metallacrown core a bending structure. The crystal structure of {[Mn(II)(C6H5COO)2][(12-MCMn(III)N(shi)-4)(CH3OH)6]}.2CH3OH (2) contains a neutral 12-membered metallacrown ring consisting of four Mn(III) and four shi(-3) ligands. The 12-membered metallacrown ring is formed by the same way of succession of four structural moieties of the type [Mn(III)-N-O], while the presence of a planar only configuration of shi ligands around ring Mn(III) ions gives to the metallacrown core a planar structure. The encapsulated Mn(II) is six and seven-coordinate for (1) and (2), respectively, and is bound to the hydroximate oxygen of the metallacrown core and two oxygen atoms from the carboxylate ligands. Antibacterial screening data showed that, among all the compounds tested, manganese metallacrowns are more active compared to the simple manganese herbicide or carboxylate complexes, with increased efficiency for [15-MCMn(III)N(shi)-5] compared to the analogous [12-MCMn(III)N(shi)-4].
Dendrinou-Samara
Catherine
C
Department of General and Inorganic Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54124, Greece.
Papadopoulos
Athanasios N
AN
Malamatari
Dora A
DA
Tarushi
Alketa
A
Raptopoulou
Catherine P
CP
Terzis
Aris
A
Samaras
Elias
E
Kessissoglou
Dimitris P
DP
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D002264:Carboxylic Acids / Q000737:chemistry* / Q000378:metabolism; D002412:Cations / Q000737:chemistry; D018360:Crystallography, X-Ray; D004988:Ethers, Cyclic / Q000737:chemistry*; D006540:Herbicides / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D008345:Manganese / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry* / Q000494:pharmacology; D012457:Salicylamides / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship
D000900:Anti-Bacterial Agents; D002264:Carboxylic Acids; D002412:Cations; D004988:Ethers, Cyclic; D006540:Herbicides; D008024:Ligands; D009942:Organometallic Compounds; D012457:Salicylamides; D008345:Manganese; C005703:salicylhydroxamic acid