Kui-Rong Ma

Facile synthesis and photo-physical properties of cyano-substituted styryl derivatives based on carbazole/phenothiazine

Four new cyano-substituted styryl derivatives based on carbazole and phenothiazine were facilely synthesized by conventional Knoevenagel condensation and well characterized. The UV-vis spectra of these dyes showed the lowest-energy absorption bands were mainly caused by the HOMO-LUMO one-electron promotion as conformed by TD-DFT calculations. The thermogravimetric analysis showed these dyes were thermally stable up to 350 °C. The UV-vis absorption and fluorescence emission spectra were also studied in solvents of different polarity, these dyes exhibited unusual large Stokes shift.

Experimental and DFT studies on the vibrational and electronic spectra of 9-p-tolyl-9H-carbazole-3-carbaldehyde.

The compound 9-p-tolyl-9H-carbazole-3-carbaldehyde (HCCD) was synthesized and characterized by X-ray diffraction, FT-IR, FT-Raman and UV-Vis spectra. The X-ray diffraction study showed that HCCD has a Z-configuration. The benzene ring including methyl is twisted from the mean plane of the carbazole group by 59.7(3)°, which is comparable with the calculated result 65° for B3LYP/6-311++G(d, p) method. Vibrational spectra and electronic spectra measurements were made for the compound. Optimized geometrical structure and harmonic vibrational frequencies were computed with B-based DFT (BLYP, B3LYP and cam-B3LYP) methods, and WB-based DFT (WB97, WB97X and WB97XD) methods and ab initio RHF method using 6-311++G(d, p) basis set. Assignments of the observed spectra were proposed. The equilibrium geometries computed by all of the methods were compared with X-ray diffraction results. The absorption spectra of the title compound were computed both in gas phase and in DMF solution using TD-(cam)B3LYP/6-311++G(d, p) and PCM-(cam)B3LYP/6-311++G(d, p) approaches, respectively. The calculated results provide good descriptions of the bands maxima in the observed electronic spectrum. Temperature dependence of thermodynamic parameters in the range of 100-1000 K was determined. The natural atomic hybrids were calculated and discussed.

Experimental and DFT studies on the vibrational, electronic spectra and NBO analysis of thiamethoxam.

Vibrational and electronic spectral measurements were performed for 3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro) amine (thiamethoxam). Optimized geometrical structure and harmonic vibrational frequencies were calculated with ab initio RHF and DFT (B3LYP, CAMB3LYP, M06 and PBE1PBE) methods with 6-311++G (d, p) basis set. Complete assignments of the observed spectra were proposed. The absorption spectra of the compound were computed in gas-phase using TD-B3LYP/6-311++G (d, p) approach and H2O solution using PCM-TD-B3LYP/6-311++G (d, p) approach. The calculated results matched well with the experimental values. Temperature dependence of thermodynamic parameters in the range of 100-1000 K were determined. The bond orbital occupancies, contribution from parent natural bond orbital (NBO), the natural atomic hybrids was discussed.

Synthesis, structural characterization and theoretical approach of the tri(2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) cobalt(II).

The crystal structure of a new coordination compound tri(2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) Co(II) complex ([Co(dcpip)3]Cl2) was measured with X-ray diffraction measurements. The compound is crystallizes triclinic, Pī space group. The ligand, 2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline(dcpip), binds to Co(II) ions with a bis-dentate mode, and each Co(II) ion with a distorted octahedral coordination geometry. The calculated interaction energies of Co(II) with coordination atoms N are between 101.7-206.5 kJ/mol and 115.3-230.9 kJ/mol for B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) theoretical methods, respectively. The experimental Fourier transform infrared spectrum was assigned. The calculated IR based on B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) methods were performed and compared with experimental results. The UV-Vis experimental spectrum of [Co(dcpip)3]Cl2 was measured in methanol solution. The calculated electronic spectrum was performed with TD/B3LYP and TD/PBE1PBE methods with 6-31+G(∗) basis set. The first and second order hyperpolarizability for the compound was calculated. The calculated values of γtot are -1.5551344 × 10(-33) esu for B3LYP method and -1.3323259 × 10(-33) esu for PBE1PBE method. The nature bond orbital analysis and temperature dependence of the thermodynamic properties were calculated with the same methods.

Two M(II)-1,5-NDS-dafo supramolecular architectures (M = Cu, Cd): syntheses, structures, and photoluminescence properties

Under hydrothermal conditions, reaction of Cu(II)/Cd(II) salts with 1,5-naphthalenedisulfonate (1,5-NDS) and 4,5-diazafluoren-9-one (dafo) afforded [Cu(dafo)2(1,5-NDS)]n (1) and [Cd(dafo)2(1,5-NDS)]n (2), respectively. The compounds were characterized by elemental analysis, IR, PXRD, TG-DSC, and single-crystal X-ray diffraction. Both 1 and 2, which are the first M(II)-1,5-NDS-dafo systems, exhibit 3-D supramolecular structures generated by 1-D chains via C–H⋯O hydrogen bonds and π–π interactions. Solid-state photoluminescence properties of both 1 and 2 were investigated with emission bands at 426–496 nm (λ ex = 280, 270 nm for 1 and 2, respectively).

catena-[[(nitrato-κO)silver(I)]-μ-1,10-phenanthroline-5,6-dione-κ4O,O′:N,N′]

In the title one-dimensional coordination polymer, [Ag(NO3)(C12H6N2O2)]n, the AgI atom is pentacoordinated by two N atoms from a 1,10-phenanthroline-5,6-dione (phen-dione) ligand, one O atom from the nitrate anion and two O atoms from another phen-dione ligand. The coordination environment around silver is slightly distorted square-pyramidal. Interestingly, the Ag—O distances to the phen-dione ligand are different [Ag—O = 2.612 (6) and 2.470 (5) Å]. The one-dimensional chains run parallel to [101] and are further interconnected by weak hydrogen bonds (C—H⋯O) and π–π stacking interactions [centroid–centroid distances 3.950 (4) and 3.792 (4) Å], forming a three-dimensional supramolecular network.

Structures and Spectroscopy Studies of Two M(II)-Phosphonate Coordination Polymers Based on Alkaline Earth Metals (M = Ba, Mg)

The two examples of alkaline-earth M(II)-phosphonate coordination polymers, [Ba2(L)(H2O)9]·3H2O (1) and [Mg1.5(H2O)9]·(L-H2)1.5·6H2O (2) (H4L = H2O3PCH2N(C4H8)NCH2PO3H2), N,N′-piperazinebis(methylenephosphonic acid), (L-H2 = O3PH2CHN(C4H8)NHCH2PO3) have been hydrothermally synthesized and characterized by elemental analysis, FT-IR, PXRD, TG-DSC, and single-crystal X-ray diffraction. Compound 1 possesses a 2D inorganic-organic alternate arrangement layer structure built from 1D inorganic chains through the piperazine bridge, in which the ligand L−4 shows two types of coordination modes reported rarely at the same time. In 1, both crystallographic distinct Ba(1) and Ba(2) ions adopt 8-coordination two caps and 9-coordination three caps triangular prism geometry structures, respectively. Compound 2 possesses a zero-dimensional mononuclear structure with two crystallographic distinct Mg(II) ions. Free metal cations and uncoordinated anions - are joined together by static electric force. Results of photoluminescent measurement indicate three main emission bands centered at 300 nm, 378.5 nm, and 433 nm for 1 and 302 nm, 378 nm, and 434.5 nm for 2 ( nm), respectively. The high energy emissions could be derived from the intraligand transition stations of (310 nm and 382 nm,  nm), while the low energy emission (>400 nm) of 1-2 may be due to the coordination effect with metal(II) ions.