Intramolecular ether oxygen coordination in the zinc complexes with dipicolylamine (DPA)-derived ligands

Mikata, Yuji; Fujimoto, Takao; Fujiwara, Tomomi; Kondo, Shin-ichi

doi:10.1016/j.ica.2011.02.022

Cited by 11 publications

(5 citation statements)

References 43 publications

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“…On the one hand, a survey of the CSD revealed that, in the few known penta-coordinated [Zn(R-bpa)Br 2 ] complexes, the bpa ligand is bound to the central metal as mer -isomer. ,,,, On the other hand, even for a significantly broader class of compounds, namely, [M(R-bpa)X 2 ] complexes containing any transition metal M or any halogen ions X, the bpa fac -isomer was found relatively rarely in the solid state, with only a handful of structures in the literature. ,− …”

Section: Resultsmentioning

confidence: 99%

Structural Variety of Isopropyl-bis(2-picolyl)amine Complexes with Zinc(II) and Copper(II)

Juraj

Muratović

Perić

et al. 2020

Crystal Growth & Design

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A variety of structurally different complexes of the isopropyl-bis(2-picolyl)amine ( i Pr-bpa) ligand were prepared with ZnA2 and CuA2 salts (A = Br–, Br–/PF6 –, BF4 –/F–, ClO4 –). The choice of different counterion affected the stoichiometry, coordination number, geometry, and formation of geometrical isomers. Crystal structures of four Zn(II) complexes, namely, two monomers ( mer -[Zn( i Pr-bpa)Br 2 ] and fac -[Zn( i Pr-bpa)Br 2 ]), one F–-bridged dimer ([Zn 2 (μ-F) 2 ( i Pr-bpa) 2 ](BF 4 ) 2 ), and one ML 2 complex ([Zn( i Pr-bpa) 2 ](ClO 4 ) 2 ) were determined, and their solution structures were studied by NMR spectroscopy. For the ML 2 complex, relative stabilities of geometrical isomers were determined using density functional theory calculations. For Cu(II) complexes, five crystal structures were determined, namely, two monomers ([Cu( i Pr-bpa)Br 2 ] and [Cu( i Pr-bpa)(ClO 4 ) 2 (H 2 O)]), a Br–-bridged dimer ([Cu 2 (μ-Br)(Br) 2 ( i Pr-bpa) 2 ](PF 6 )), a F–-bridged coordination polymer ([Cu(μ-F)( i Pr-bpa)] n (BF 4 ) n × nCH 3 OH), and a cyclic, CO3 2–-bridged trimer ([Cu 3 (tri-μ-CO 3 )(ClO 4 ) 3 ( i Pr-bpa) 3 ](ClO 4 )). The different crystallographic structures of Cu(II) complexes are reflected in their different magnetic properties investigated by electron spin resonance spectroscopy and magnetic susceptibility measurements.

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Section: Resultsmentioning

confidence: 99%

Structural Variety of Isopropyl-bis(2-picolyl)amine Complexes with Zinc(II) and Copper(II)

Juraj

Muratović

Perić

et al. 2020

Crystal Growth & Design

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“…This feature is also seen in the 1 H NMR spectrum of the 2:1 complex in solution (vide infra). The 2:1 (ligand/zinc(II)) octahedral complexes involving two N , N -di(2-picolyl)amino (DPA) tridentate ligands are relatively rare. − Despite the difference in the N -substituent of the DPA ligands, all but one of the reported cases share the same fac / C 2 -symmetric stereoisomer, suggesting a thermodynamic preference for its formation.…”

Section: Results and Discussionmentioning

confidence: 99%

Integrated and Passive 1,2,3-Triazolyl Groups in Fluorescent Indicators for Zinc(II) Ions: Thermodynamic and Kinetic Evaluations

et al. 2013

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In addition to being a covalent linker in molecular conjugation chemistry, the function of a 1,2,3-triazolyl moiety resulting from the copper(I)-catalyzed azide-alkyne cycloaddition reaction as a ligand for metal ions is receiving considerable attention. In this work, we characterize the thermodynamic and kinetic effects of incorporating a 1,2,3-triazolyl group in a multidentate ligand scaffold on metal coordination in the context of fluorescent zinc(II) indicator development. Ligands L14, BrL14, and FL14 (1,4-isomers) contain the 1,4- disubstituted-1,2,3-triazolyl group that is capable of binding with zinc(II) in conjunction with a di(2-picolylamino) (DPA) moiety within a multidentate ligand scaffold. The 1,2,3-triazolyl in the 1,4-isomers is therefore “integrated” in chelation. The 1,5-isomers L15, BrL15, and FL15 contain 1,2,3-triazolyls that are excluded from participating in zinc(II) coordination. These 1,2,3- triazolyls are “passive linkers”. Zinc(II) complexes of 2:1 (ligand/metal) stoichiometry are identified in solution using 1H NMR spectroscopy and isothermal titration calorimetry (ITC), and in one case, characterized in the solid state. The 1:1 ligand/zinc(II) affinity ratio of L14 over L15, which is attributed to the affinity enhancement of a 1,2,3-triazolyl group to zinc(II) over that of the solvent acetonitrile, is quantified at 18 (−1.7 kcal/mol at 298 K) using an ITC experiment. Fluorescent ligands FL14 and FL15 are evaluated for their potential in zinc(II) sensing applications under pH neutral aqueous conditions. The 1,4-isomer FL14 binds zinc(II) both stronger and faster than the 1,5-isomer FL15. Visualization of free zinc(II) ion distribution in live HeLa cells is achieved using both FL14 and FL15. The superiority of FL14 in staining endogenous zinc(II) ions in live rat hippocampal slices is evident. In summation, this work is a fundamental study of 1,2,3-triazole coordination chemistry, with a demonstration of its utility in developing fluorescent indicators.

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“…[45][46] 1 H NMR (300 MHz) and 13 C NMR (75.5 MHz) spectra were recorded on a Varian GEMINI 2000 spectrometer and referenced to internal Si(CH 3 ) 4 or solvent signals. Compounds L Py and LЈ Py were prepared according to published procedures.…”

Section: Methodsmentioning

confidence: 99%

“…General: All reagents and solvents used for ligand synthesis were from commercial sources and used as received. Compounds L Py and L′ Py were prepared according to published procedures 45–46 . 1 H NMR (300 MHz) and 13 C NMR (75.5 MHz) spectra were recorded on a Varian GEMINI 2000 spectrometer and referenced to internal Si(CH 3 ) 4 or solvent signals.…”

Section: Methodsmentioning

confidence: 99%

Differentiation of Oxygen Atom Chirality in Copper(II) Complexes with Dipicolylamine‐Derived Ligands

et al. 2012

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The ether coordination of the oxygen atom to the copper(II) center supported by dipicolylamine (DPA)‐derived ligands,N‐[2‐(2‐pyridylmethyloxy)ethyl]‐N,N‐bis(2‐pyridylmethyl)amine (LPy), N‐[2‐(2‐quinolylmethyloxy)ethyl]‐N,N‐bis(2‐pyridylmethyl)amine (LQ), N‐[3‐(2‐pyridylmethyloxy)‐1‐propyl]‐N,N‐bis(2‐pyridylmethyl)amine (L′Py), N‐{2‐[1‐(2‐pyridyl)ethyloxy]ethyl}‐N,N‐bis(2‐pyridylmethyl)amine (LPy*1), N‐[2‐(2‐pyridylmethyloxy)‐1‐propyl]‐N,N‐bis(2‐pyridylmethyl)amine (LPy*2), and N‐[2‐(carboxymethyloxy)ethyl]‐N,N‐bis(2‐pyridylmethyl)amine (HLCOO), have been examined. The factors that facilitate the coordination of the ether oxygen atom of these ligands to the copper center and the control of chirality around the copper‐coordinated oxygen atom are discussed. The copper center exhibits a pentacoordinate geometry with these ligands, as evidenced by X‐ray crystallography. The steric effect of the quinoline ring in the LQ complex prevents the coordination of a perchlorate anion to the copper center, which affords the pentacoordinate divalent complex with a shorter copper–oxygen bond than that for the corresponding pyridine ligand (LPy). The six‐membered chelate in the L′Py complex also exhibits a shorter Cu–O distance. The conformation of the oxygen atom of the LPy complex is unstable because of fast lone pair inversion, but this inversion is prevented for the complexes with chiral ligands, LPy*1 and LPy*2. Upon chelation to the metal center, the HLCOO ligand forms a pentacoodinate monomer complex that further affords a 1‐D polymer structure. With respect to the oxygen chirality, the water content of the solvent governs the formation of either a homochiral polymer (R‐R‐R‐R‐ or S‐S‐S‐S‐) or an alternative chirality polymer (R‐S‐R‐S‐). In this case, the isomers with respect to the oxygen chirality were separated and characterized.

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Intramolecular ether oxygen coordination in the zinc complexes with dipicolylamine (DPA)-derived ligands

Cited by 11 publications

References 43 publications

Structural Variety of Isopropyl-bis(2-picolyl)amine Complexes with Zinc(II) and Copper(II)

Structural Variety of Isopropyl-bis(2-picolyl)amine Complexes with Zinc(II) and Copper(II)

Integrated and Passive 1,2,3-Triazolyl Groups in Fluorescent Indicators for Zinc(II) Ions: Thermodynamic and Kinetic Evaluations

Differentiation of Oxygen Atom Chirality in Copper(II) Complexes with Dipicolylamine‐Derived Ligands

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