The effects of conformation and coordination to zinc(II) ions on the luminescence properties of 2,2′-bipyridine, methyl-substituted 2,2′-bipyridines and 2,2′-biquinoline

Yagi, Mikio; Kaneshima, Takashi; Wada, Y.; Takemura, Kazumasa; Yokoyama, Yukio

doi:10.1016/1010-6030(94)03842-2

Cited by 19 publications

(4 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Discussionmentioning

confidence: 99%

“…Additional support for this conclusion stems from the weak emission observed in compounds 1, 5, 6, and 7 where N-donors are either absent or serve simply as guests. Moreover, the triplet states of BPY (23 419 cm −1 ), 87 4-MeBPY (23 310 cm −1 ), 87 and 5-MeBPY (22 831 cm −1 ) 87 with respect to the emissive UO 2 2+ state (21 321 cm −1 ) 44 are well suited for possible energy transfer (in lanthanide systems, a "safe" energy difference between 2500 and 3500 cm −1 allows for efficient transfer). 88 That said, given that the UO 2 2+ coordination spheres in 1, 5, 6, and 7 are saturated with TDC linkers (Figure 9), one may also speculate that their extended conjugation may cause the uranyl cations to be electronically indistinct, as observed in a similar study using 1,2-(4-pyridyl)-ethylene and 1,2-(4-pyridyl)ethane, respectively, 21 and thus results in weakened or quenched uranyl emission.…”

Section: ■ Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Role of N-Donor Sterics on the Coordination Environment and Dimensionality of Uranyl Thiophenedicarboxylate Coordination Polymers

Thangavelu

Butcher

Cahill

2015

Crystal Growth & Design

View full text Add to dashboard Cite

Thiophene 2,5-dicarboxylic acid (TDC) was reacted with uranyl acetate dihydrate and one (or none) of six N-donor chelating ligands (2,2′-bipyridine (BPY), 4,4′-dimethyl-2,2′-bipyridine (4-MeBPY), 5,5′-dimethyl-2,2′-bipyridine (5-MeBPY), 6,6′-dimethyl-2,2′-bipyridine (6-MeBPY), 4,4′,6,6′-tetramethyl-2,2′-bipyridine (4,6-MeBPY), and tetrakis(2-pyridyl)pyrazine (TPPZ) to result in the crystallization of seven uranyl coordination polymers, which were characterized by their crystal structures and luminescence properties. The seven coordination polymers, Na 2 [(UO 2 ) 2 (C 6 H 2 O 4 S) 3 ]· (7), consist of either uranyl hexagonal bipyramidal or pentagonal bipyramidal coordination geometries. In all structures, structural variations in the local and global structures of 1−7 are influenced by the positions (or number) of methyl groups or pyridyl rings on the N-donor species, thus resulting in a wide diversity of structures ranging from single chains, double chains, or 2-D sheets. Direct coordination of N-donor ligands to uranyl centers is observed in the chain structures of 2−4 using BPY, 4-MeBPY, and 5-MeBPY, whereas the N-donor species participate as guests (as either neutral or charge balancing species) in the chain and sheet structures of 5−7 using 6-MeBPY, 4,6-MeBPY, and TPPZ, respectively. Compound 1 is the only structure that does not contain any N-donor ligands and thus crystallizes as a 2-D interpenetrating sheet. The luminescent properties of 1−7 are influenced by the direct coordination or noncoordination of N-donor species to uranyl centers. Compounds 2−4 exhibit typical UO 2 2+ emission upon direct coordination of N-donors, but its absence is observed in 1, 5, 6, and 7, when N-donor species participate as guest molecules. These results suggest that direct coordination of N-donor ligands participate as chromophores, thus resulting in possible UO 2 2+ sensitization. The lack of emission in 1, 5, 6, and 7 may be explained by the extended conjugation of the TDC ligands within their structures. ■ INTRODUCTIONCoordination polymers (CPs) constructed from the uranyl cation (UO 2 2+ ) continue to remain attractive in the field of hybrid materials owing to their unique structural and luminescent properties. 1 The UO 2 2+ cation is a linear triatomic species that contains two axial oxygen atoms about the central uranium atom, the terminal nature of which promotes additional ligand coordination about the equatorial plane. 2 This results in three types of UO 2 2+ primary building units (PBUs) found as square, pentagonal, or hexagonal bipyramidal geometries. The uranyl cation may also undergo hydrolysis and subsequent condensation to form secondary building units (SBUs) in the form of dimers, trimers, or tetramers, etc. 3,4 UO 2 2+ hydrolysis under hydrothermal conditions is a dynamic process wherein multiple speciation products are present in a wide range of pH and concentration. 5−7 This, in turn, makes it challenging to predict or control the type of uranyl building unit that will ultimately be observed in the solid st...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: ■ Discussionmentioning

confidence: 99%

Role of N-Donor Sterics on the Coordination Environment and Dimensionality of Uranyl Thiophenedicarboxylate Coordination Polymers

Thangavelu

Butcher

Cahill

2015

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…9. The excitations were carried out with a Canrad-Hanovia 1 kW Xe-Hg lamp through a Toshiba UV-D33S glass filter, 5 cm of distilled water, and a Copal DC-494 electromechanical shutter.…”

Section: Methodsmentioning

confidence: 99%

Optical and time-resolved electron paramagnetic resonance studies of the excited states of para-methylcinnamic acid and para-methylcinnamate anion

et al. 2003

Self Cite

View full text Add to dashboard Cite

Time-resolved electron pammagnetic resonance (EPR), fluorescence, and phosphorescence spectra have been observed for the excited states of trans-p-methylcinnamic acid (p-MeCA) and transp-methylcinnamate anion (p-MeCA-) in rigid organic glasses at 77 K. With a stretched-polymer-film techrtique, we assigned the resonance fields in the time-resolved EPR spectra of the lowest excited t¡ (T~) states of p-MeCA and p-MeCA-. From the analysis of these spectra we concluded that the deviation from planar structure in the T~ state is small in p-MeCA and p-MeCA-and the direction of C=O is s-cis to the ethylenic C=C bond in p-MeCA. The deprotonation appears to have little effect on the zero-field splitting (ZFS) parameters. The ZFS parameters were calculated theoretically using semiempi¡ molecular orbitals. The sublevel preferentially populated by intersystem crossing (ISC) is Ty in both p-MeCA and p-MeCA-. However, following the deprotonation of p-MeCA, (Py -P~)/(Px -P~) changes from 5.7 in p-MeCA to 2.1 in p-MeCA-(Pi are relative populating rates; the x and y axes are close to the Iong and short in-plane molecular axes, respectively, and z-axis is perpendicular to the molecular plane). The fluoreseenee lifetimes indicate that the deprotonation has little effeet on the sum of the three [SC rate constaats for the three T~ sublevels. A decrease in aeidity of p-MeCA upon exeitation has been observed.

show abstract

“…Having at hand the desired peptides we proceeded with the study of their metal binding properties. Surprisingly, while 2,2′-bipyridine is weakly emissive, and is even considered non-fluorescent (Dhanya and Bhattacharyya, 1992 ; Yagi et al, 1994 ), we found that the asymmetric 5′-amido-[2,2′-bipyridine]-5-carboxamide unit within the βAlaBpy residue was highly emissive, displaying intense band at c.a. 420 nm with a quantum yield of 0.37 (Dong et al, 2017 ).…”

Section: Resultsmentioning

confidence: 62%

Directed Self-Assembly of Trimeric DNA-Bindingchiral Miniprotein Helicates

et al. 2018

View full text Add to dashboard Cite

We propose that peptides are highly versatile platforms for the precise design of supramolecular metal architectures, and particularly, for the controlled assembly of helicates. In this context, we show that the bacteriophage T4 Fibritin foldon (T4Ff) can been engineered on its N-terminus with metal-chelating 2,2′-bipyridine units that stereoselectively assemble in the presence of Fe(II) into parallel, three-stranded peptide helicates with preferred helical orientation. Modeling studies support the proposed self-assembly and the stability of the final helicate. Furthermore, we show that these designed mini-metalloproteins selectively recognize three-way DNA junctions over double-stranded DNA.

show abstract

The effects of conformation and coordination to zinc(II) ions on the luminescence properties of 2,2′-bipyridine, methyl-substituted 2,2′-bipyridines and 2,2′-biquinoline

Cited by 19 publications

References 24 publications

Role of N-Donor Sterics on the Coordination Environment and Dimensionality of Uranyl Thiophenedicarboxylate Coordination Polymers

Role of N-Donor Sterics on the Coordination Environment and Dimensionality of Uranyl Thiophenedicarboxylate Coordination Polymers

Optical and time-resolved electron paramagnetic resonance studies of the excited states of para-methylcinnamic acid and para-methylcinnamate anion

Directed Self-Assembly of Trimeric DNA-Bindingchiral Miniprotein Helicates

Contact Info

Product

Resources

About