Dicopper(II) complexes of a phenolate-hinged ditopic ligand with solvent-derived ancillary ligands bound at the potentially dimetallic exogenous site

“…The acetonitrile mass spectrometry of [Cu 2 (L Me -O) 2 (OCH 3 )](ClO 4 ) 2 revealed a peak at m/z 357.1, which is located at about the same positions as for complexes 1-4 was incorrectly assigned for [Cu 2 (L Me -O) 2 (OH)] 2+ ion. 27 In addition to these peaks, the hexafluorophosphate complexes 1, 2, 4 and 5 displayed an m/z peak at 144.97 (100%) for PF 4) Å] (Fig. S6 †).…”

Section: Mass Spectral Characterization Of Complexesmentioning

confidence: 99%

Magnetic and structural properties of dinuclear singly bridged-phenoxido metal(ii) complexes

et al. 2015

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The reaction of a methanolic solution containing the bi-compartmental phenolic ligand 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenol (L(Cl)-OH) with MCl2·nH2O in the presence of NH4PF6 or NaClO4 afforded the dinuclear bridged-phenoxido dichlorido-metal(ii) complexes [Co2(μ-L(Cl)O)(H2O)2Cl2][Co2(μ-L(Cl)O)(MeOH)2Cl2](PF6)2 (), [Ni2(μ-L(Cl)O)(MeOH)2Cl2]PF6 (), [Ni2(μ-L(Cl)O)(MeOH)(H2O)Cl2]ClO4·1.25H2O (), [Cu2(μ-L(Cl)O)Cl2]PF6·1/2MeOH () and [Zn2(μ-L(Cl)O)Cl2]PF6·MeOH (). The complexes were characterized by elemental microanalyses, conductivity measurements, IR and UV-Vis spectroscopy, mass spectrometry and single crystal X-ray crystallography. Each M(ii) center within the dinuclear complex cations is octahedrally coordinated in complexes , and five-coordinated distorted square pyramidal in and . Magnetic susceptibility measurements at variable temperature of the complexes revealed weak to moderate antiferromagnetic coupling with |J| values = 8.38, 39.0, 30.2 and 0.79 cm(-1), respectively. The results of DFT calculations correlate well with the experimentally determined antiferromagnetic coupling and show that the magnetic exchange coupling occurs mainly through the phenoxido bridge M-O-M. Implications of geometry around the central metal ion, MM distance, M-O-M bond angle and overlapping of magnetic orbitals on the magnetic exchange coupling are discussed.

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“…ClO4)2·H2O31 were prepared as previously described. The procedures for the synthesis of the remaining complexes, dephosporylation and methylation of carboxylic acids in βcas are presented in the supporting information.…”

mentioning

confidence: 99%

Effect of Metals in Biomimetic Dimetal Complexes on Affinity and Gas-Phase Protection of Phosphate Esters

et al. 2015

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Although the biomimetic dimetal complex [LGa2(OH)2(H2O)2](3+) [L = 2,6-bis((N,N'-bis(2-picolyl)amino)methyl)-4-tertbutylphenolate] provides efficient protection against phosphate loss in phosphopeptides upon collision-induced dissociation tandem mass spectrometry (CID MS/MS), the underlying mechanism remains unknown. Here, we explored the mechanism in detail and investigated the selective binding to phosphate groups in solution. Dimetal complexes containing combinations of Ga(3+), In(3+), Fe(3+), Co(3+), Zn(2+), Cu(2+), and V(2+) were reacted with HPO4(2-), phosphoserine, and a phosphopeptide (FQpSEEQQQTEDELQDK, abbreviated "βcas") and studied with isothermal titration calorimetry (ITC), CID MS/MS, and density functional theory (DFT). Ka for HPO4(2-) binding scaled with the metal charge and was 35-fold larger for [LGa2(OH)2(H2O)2](3+) (3.08 ± 0.31 × 10(6) M(-1)) than for [LZn2(HCOO)2](+). CID MS/MS of [LGa2(βcas)](n+) revealed protection against phosphate detachment (<3% of the total ion intensity). Phosphate detachment from βcas was 22-40% and increased to 42-71% when bound to dimetal complexes of lower charge than {LGa2}(5+). CID data suggests that facile metal-phosphate dissociation is associated with proton transfer from the intermediate oxazoline ring formed in the phosphopeptide to the metal-phosphate complex. The observed phosphate stabilization was attributed to a significant reduction in the gas-phase basicity (GB) of the phosphate group when bound to {LGa2}(5+)/{LIn2}(5+) complex cores. Absence of proton transfer results in formation of an ion-zwitterion intermediate with a greater dissociation threshold. This hypothesis is supported by DFT calculations for [LGa2(PO4)](2+), [LGaZn(PO4)](+), [LZn2(PO4)], and 2,4-dimethyl-3-oxazoline showing that [LGa2(PO4)](2+) is the only compound with a substantial lower GB (321 kJ/mol less) than 2,4-dimethyl-3-oxazoline.

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Dicopper(II) complexes of a phenolate-hinged ditopic ligand with solvent-derived ancillary ligands bound at the potentially dimetallic exogenous site

Cited by 21 publications

References 10 publications

Synthesis, structure and magnetic characterization of dinuclear copper(ii) complexes bridged by bicompartmental phenolate

Synthesis, structure and magnetic characterization of dinuclear copper(ii) complexes bridged by bicompartmental phenolate

Magnetic and structural properties of dinuclear singly bridged-phenoxido metal(ii) complexes

Effect of Metals in Biomimetic Dimetal Complexes on Affinity and Gas-Phase Protection of Phosphate Esters

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