Xin Gan

Intense one- and two-photon excited fluorescent bis(BF2) core complex containing a 1,8-naphthyridine derivative.

The first bis(BF(2)) core complex containing a 1,8-naphthyridin derivative (1,2-bis(5,7-dimethyl-1,8-naphthyridin-2-yl)hydrazine) and with yellow-green emission as well as a high quantum yield was synthesized and structurally characterized, and the compound exhibits two-photon absorption and excited fluorescence properties.

The influence of the carbon double bond on the structure and photophysical properties of copper(I) coordination polymers

The reaction of [Cu(CH3CN)4]BF4, pyridine-2-carbaldehyde azine, triphenylphosphine, and diimine ligands derived from 4,4′-bipyridine and/or trans-1,2-bis(4-pyridyl)ethylene gave two copper(I) coordination polymers, [Cu2(µ-paa)(µ-bp)(PPh3)2] n (BF4)2 n (1) and [Cu2(µ-paa)(µ-tbpe)(PPh3)2] n (BF4)2 n (2). Despite 1 and 2 differing only by a double bond, they have significantly different photophysical and structural properties. Crystallographic studies show that 2 is a porous solid while 1 is not porous. The two polymers are photoluminescent as solids at room temperature, but the emission peaks of 2 are obviously red-shift. Moreover, different from 1, 2 has a good emission centered at 510 nm in CH3CN solution. The double bond in the diimine ligand plays an important role in these two copper(I) coordination polymers.

A flexible 1,8-naphthyridyl derivative and its Zn(II) complexes: synthesis, structures, spectroscopic properties and recognition of Cd(II)

A flexible ligand bis(7-methyl-1,8-naphthyridine-2-ylamino)methane (), having kappa(4)-chelating and kappa(2)-bridging modes, and its intriguing structural complexes of Zn(II) with mu-OH, kappa(1)-OAc, mu-kappa(1)-OAc and mu-kappa(2)-OAc ligands, [Zn(2)()(2)(OH)](ClO(4))(3) (), [Zn(4)()(2)(OAc)(6)(OH)(2)].CH(2)Cl(2) (.CH(2)Cl(2)) and [Zn(5)()(2)(OAc)(10)](n).4nH(2)O (.4H(2)O) were synthesized and their structures were determined by X-ray crystallography. These compounds exhibited intense blue fluorescent emissions with a lambda(max) in the range of 380-410 nm in CH(2)Cl(2), CH(3)CN and CH(3)OH solutions, and solid-state emissions centered at 416, 463, 490 and 451 nm were observed for the compounds , , and at room temperature, respectively. The investigated fluorescence properties of associated with various metal ions showed that the fluorescence enhancement of with Cd(II) was more sensitive than with other interfering cations.

Synthesis, characterization, and spectroscopic properties of binuclear copper(I) complexes with N^N-N^N, N^N^OH, N^C^N, and phosphine ligands

Three new binuclear copper(I) complexes, [Cu2(paa)(dppm)2](BF4)2 (1), [Cu2(N^N^O)(dppm)2]BF4 (2), and [Cu2(N^C^N)(dppm)2](BF4)2 (3), were prepared with bridging or chelating pyridine-2-carbaldehyde azine (paa or N^N-N^N), 2,4-dimethyl-7-hydroxyl-1,8-naphthyridine (N^N^OH), 1-methyl-3,5-di(2-pyridyl)benzene (N^C^N), and bis(diphenylphosphino)methane (dppm) ligands and their structures were determined by X-ray crystal analysis. The structural analysis revealed that coppers in the complexes are three- and four-coordinate and N^N-N^N adopts N,N chelating and bridging coordination modes while N^N^OH, N^C^N and dppm afforded only a bridging model. The two metal centers approach closely with copper(I)–copper(I) distances of 2.7811–3.420 Å. Intense solid-state emission centered at 490 nm was observed for 1.

Synthesis, structures, and spectroscopic properties of copper(I) complexes bearing 7-acetamido-4-methyl-1,8-naphthyridin-2-carbaldehyde azine and 1,2-bis(diphenylphosphino)ethane ligands

A new ligand napaa (napaa = 7-acetamido-4-methyl-1,8-naphthyridin-2-carbaldehyde azine) and its two dinuclear copper(I) complexes, Cu2(napaa)(dppe)2(ClO4)2 (1) and Cu2(napaa)(PPh3)4(BF4)2 (2) (dppe = 1,2-bis(diphenylphosphino)ethane) and PPh3 = triphenylphosphine) were synthesized and characterized, and the structure of 1 was determined by X-ray crystal analysis. Each copper atom in 1 has a distorted tetrahedral geometry in which the metal center is associated to napaa and dppe ligands displaying chelating coordination modes and the naphthyridine rings of napaa are almost coplanar. The two complexes exhibit similar electronic absorption spectra with λmax at about 366 nm, which can be tentatively assigned to metal-to-ligand charge-transfer (MLCT) transition. The assignment was further supported by density functional theory (DFT) calculations.

A novel triply bridged dinuclear four-coordinate copper(I) complex with sterically bulky bis(dicyclohexylphosphino)methane ligand

A novel triply bridged dinuclear copper(I) complex: Cu2(μ-paa)(μ-dcpm)2(BF4)2·2CH2Cl2 [ paa = pyridine-2-carbaldehyde azine (C12H10N4) and dcpm = bis(dicyclohexylphosphino)methane(C25H46P2) ] has been synthesized and structurally characterized. Crystallographic studies of the complex showed that two copper(I) ions were bridged by one paa ligand and two dcpm ligands. The paa ligand adopted the Z configuration at the partially double N-N bond and the two copper ions have distorted tetrahedral coordination geometry. Because of the steric effect of dcpm, the pyridine rings of the paa ligand are obviously not on the same plane (the dihedral angle is 43.610). The interaction between neighboring ligands results in a N-N bond length (1.374(7) Å) contraction. The UV-vis spectra of the complex exhibited intense high-energy absorptions at λmax < 340 nm and broad visible bands in a range of 380−550 nm, ascribed to intraligand (IL π-π*) transitions and metal-to-ligand charge-transfer (MLCT) transitions, respectively. Interestingly, the absorbtion peaks varied regularly with the solvent polarity. Although the complex has a rigid structure with the copper ions held firmly by triply bridged ligands, the emission and excitation spectra revealed that the complex exhibits weak fluorescence.

CCDC 615574: Experimental Crystal Structure Determination

Related Article: Wen-Fu Fu, Xin Gan, Jian Jiao, Yong Chen, Mei Yuan, Shao-Ming Chi, Ming-Ming Yu, Shao-Xiang Xiong|2007|Inorg.Chim.Acta|360|2758|doi:10.1016/j.ica.2007.02.007