1245798-02-0Relevant articles and documents
Dangling and Hydrolyzed Ligand Arms in [Mn3] and [Mn6] Coordination Assemblies: Synthesis, Characterization, and Functional Activity
Chattopadhyay, Krishna,Craig, Gavin A.,Heras Ojea, María José,Pait, Moumita,Kundu, Animesh,Lee, Junseong,Murrie, Mark,Frontera, Antonio,Ray, Debashis
, p. 2639 - 2652 (2017)
Two flexible, branched, and sterically constrained di- and tripodal side arms around a phenol backbone were utilized in ligands H3L1 and H5L2 to isolate {Mn6} and {Mn3} coordination aggregates. 2,6-Bis{(1-hydroxy-2-methylpropan-2-ylimino)methyl}-4-methylphenol (H3L1) gave trinuclear complex [Mn3(μ-H2L1)2(μ1,3-O2CCH3)4(CH3OH)2](ClO4)2·4CH3OH (1), whereas 2,6-bis[{1-hydroxy-2-(hydroxymethyl)butan-2-ylimino}methyl]-4-methylphenol (H5L2) provided hexanuclear complex [Mn6(μ4-H2L2)2(μ-HL3)2(μ3-OH)2(μ1,3-O2CC2H5)4](ClO4)2·2H2O (2). Binding of acetates and coordination of {H2L1}- provided a linear MnIIIMnIIMnIII arrangement in 1. A MnIII6 fused diadamantane-type assembly was obtained in 2 from propionate bridges, coordination of {H2L2}3-, and in situ generated {HL3}2-. The magnetic characterization of 1 and 2 revealed the properties dominated by intramolecular anti-ferromagnetic exchange interactions, and this was confirmed using density functional theory calculations. Complex 1 exhibited field-induced slow magnetic relaxation at 2 K due to the axial anisotropy of MnIII centers. Both the complexes show effective solvent-dependent catechol oxidation toward 3,5-di-tert-butylcatechol in air. The catechol oxidation abilities are comparable from two complexes of different nuclearity and structure.
A New Family of Ni4 and Ni6 Aggregates from the Self-Assembly of [Ni2] Building Units: Role of Carboxylate and Carbonate Bridges
Pait, Moumita,Bauzá, Antonio,Frontera, Antonio,Colacio, Enrique,Ray, Debashis
supporting information, p. 4709 - 4723 (2015/05/27)
Carboxylato (R = tBu and Et) and carbonato bridges have been utilized for nickel(II)-based aggregates [Ni4(μ-H2L)2(μ3-OH)2(μ1,3-O2CBut)2](NO3)2·H2O·2DMF (1·H2O·2DMF), Ni4(μ-hyHL)2(μ3-OMe)2(μ1,1-N3)2(μ1,3-O2CEt)2]·4H2O (2·4H2O), and Ni6(μ4-L)(μ3-L)2(μ6-CO3)(H2O)8](ClO4)·9H2O (3·9H2O). Building blocks [Ni2(μ-H2L)]3+, [Ni2(μ-hyHL)]3+, and [Ni2(μ-L)]+ originating from [Ni2(μ-H2L)]3+ have been trapped in these complexes. The complexes have been characterized by X-ray crystallography, magnetic measurements, and density functional theory (DFT) analysis. In 1, the magnetic interactions are transmitted through the μ3-phenoxido/μ3-hydroxido/syn-syn-tBuCO2-, μ3-phenoxido/μ3- hydroxido, and double μ3-phenoxido/double μ3-hydroxido bridges with J = +11.4 cm-1, J1 = -2.1 cm-1, and J2 = -2.8 cm-1, respectively. In 2, the interactions are ferromagnetic, with J1 = +27.5 cm-1, J2 = +20.62 cm-1, and J3 = +1.52 cm-1 describing the magnetic couplings through the μ-phenoxidoo/μ3-methoxido, μ-azido/μ3-methoxido, and μ3-methoxido/μ3-methoxido exchange pathways, respectively. Complex 3 gives J1 = -3.30 cm-1, J2 = +1.7 cm-1, and J3 = -12.8 cm-1 for exchange pathways mediated by μ-phenoxido/μ-carbonato, μ-alkoxido/μ-alkooxido/μ-syn-syn-carbonato, and the μ-phenoxido/μ-carbonato, respectively. Interestingly, 1 and 3 below 20 K and 35 K, respectively, show an abrupt increase of the χMT product to reach a magnetic-field-dependent maximum, which is associated with a slightly frequency-dependent out-of-phase alternating-current peak. DFT calculations have also been performed on 1-3 to explain the exchange interaction mechanisms and to support the magnitude and sign of the magnetic coupling constants between the NiII ions. (Figure Presented).
A new water-soluble copper(II) complex as a selective fluorescent sensor for azide ion
Dhara, Koushik,Saha, Uday Chand,Dan, Abhijit,Sarkar, Sandipan,Manassero, Mario,Chattopadhyay, Pabitra
supporting information; experimental part, p. 1754 - 1756 (2010/07/08)
{[Cu2(H2L)(OH)(H2O)]·(ClO 4)2(H2O)} (1) serves as a selective azide ion fluorescent sensor in aqueous medium. 1 binds with N3- to give [Cu6(HL)2(μ1,1-N3) 6] (2) which imposes rigidity and decreases the non-radiative decay of the excited state to give rise to fluorescent enhancement. 1 is highly selective over other various anions in aqueous medium.