This study presents an investigation on polyimides derived from a unfunctionalized symmetric cyclopentyl-containing alicyclic cardo-type dianhydride with ester linkage 1,1-bis(4-(3,4-dicarboxylbenzoyloxy)phenyl)cyclopentylene dianhydride (BDPCP) that was readily accessed starting from cyclopentanone through two steps in high yield. Two series of polyimides, Cardo-type series (CPI-x) and analogous aromatic series (ArPI-x) were prepared from condensation of BDPCP and aromatic 3,3′,4,4′-Oxydiphthalic dianhydride with four aromatic diamines, respectively. Comparative studies revealed that CPI polymers show more favorable properties including better solubility in organic solvents, higher transparency with lower cut-off wavelength (λ₀) ranging in 395–375 nm than 425–405 nm, lower water absorption ranging in 0.66–1.14% and surface energy 23.71–32.77 mN/m than 1.01–1.28% and 29.52–41.99 mN/m of ArPI analogs. Meanwhile, CPI series exhibit considerable mechanical properties with tensile strengths ranging in 87.6–102.9 MPa, elongations at break 6.6–8.9%. Owing to the moderate strain in cyclopentyl ring, CPI series retain good thermal properties with the glass transition temperature (T_g) in the range of 217–271°C. Dynamic dielectric measurement revealed that Cardo-type dianhydride BDPCP endows CPI-4 film with lower dielectric constant (ε′) 3.34 at 1 MHz and 25°C and dielectric loss (ε′′) 0.0064 at 1 kHz and 25°C than 3.49 and 0.013 for ArPI-4 film. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42670.

Magnetic coordination complexes based on Schiff bases are promising new molecular materials for electronics. Two μ-oxo Fe^III dimeric complexes of enantiomers of Schiff base ligands (N,N′-(1R,2R)-1,2-diphenylethylenebis(salicylideneimine) (H₂salphen-R, 1 a) and N,N′-(1S,2S)-1,2-diphenylethylenebis(salicylideneimine) (H₂salphen-S, 1 b)) were synthesized; further reaction with 4-salicylideneamino-1,2,4-triazole (Hsaltrz) led to enantiomers of two one-dimensional (1D) Fe^III coordination complexes. The structures of these complexes were determined by X-ray diffraction. Magnetic susceptibility measurements revealed that μ-oxo dimeric complexes displayed strong antiferromagnetic coupling, whereas the 1D complexes exhibited paramagnetic behavior. The chirality of the Schiff bases transferred to macromolecular chirality of the complexes, which could be monitored by both vibrational and electronic circular dichroism (CD) spectroscopic methods. The macroscopic handedness was manifested in CD signals attributed to exciton coupling between the ligands. Thus, the chiral spectroscopies were useful to probe the chirality of the complexes, their structure, and the polymerization degree.

Two couples of enantiomeric platinum(II) complexes: Pt(L_1a)Cl (1a), Pt(L_1b)Cl (1b) and Pt(L_1a)(C ≡ C − Ph) (2a), Pt(L_1b)(C ≡ C − Ph) (2b) (L_1a = (+)-1,3-di-(2-(4,5-pinene)pyridyl)benzene, L_1b = (−)-1,3-di-(2-(4,5-pinene)pyridyl)benzene) were synthesized and characterized. Their absolute configurations were determined by single crystal X-ray diffraction and further verified by circular dichroism (CD) spectra (including electronic circular dichroism [ECD] and vibrational circular dichroism [VCD]). These complexes show interesting mechanoluminescence and/or vapoluminescence due to crystalline-to-amorphous transformation. The crystalline solids, grinding-induced amorphous powders, and vapor-induced amorphous powders of complexes 2a and 2b were comparatively investigated by solid-state ECD and VCD spectra. The transformation from crystalline solids to amorphous powders was accompanied by significant variances of the spectral feature in both ECD and VCD spectra. Chirality 25:384–392, 2013. © 2013 Wiley Periodicals, Inc.

Novel copper(II) coordination compounds with chiral macrocyclic imine ligands derived from R-/S-camphor were asymmetrically synthesized and characterized with the aid of chiroptical spectroscopies. Crystal structures of both enantiomers were determined by single crystal X-ray diffraction analysis. Circular dichroism (CD) spectra were analyzed using a simplified exciton model as well as quantum chemical computations. The absolute configuration of the copper(II) coordination compounds determined from CD was found consistent with the crystal data. The copper(II) complexes were further investigated by vibrational CD (VCD) measurement combined with density functional theory calculation. The complex formation was evidenced by spectral shifts of the characteristic bands in the CD and VCD spectra. Chirality 24:451–458, 2012. © 2012 Wiley Periodicals, Inc.

By utilizing the chiral terpyridyl-type ligand L(–) [L =“dipineno”-(4,5:4″,5″)-fused 2,2′:6′,2″-terpyridine or 2,6-bis(7,7-dimethyl-5,6,7,8-tetrahydro-6,8-methanoisoquinolin-3-yl)pyridine], two novel Eu^III complexes with the formula [Eu(tta)₃L](C₃H₆O)·0.5(H₂O) (1) and [Eu(bta)₃(L)](C₃H₆O)(2) (tta = 2-thenoyltrifluoroacetonate, bta = benzoyltrifluoroacetonate) were synthesized and characterized by X-ray crystallography and spectroscopic methods. The Eu^III atoms in 1 and 2 are nine-coordinate in a geometrical environment of a distorted, monocapped square antiprism. Complex 1 crystallizes in the polar space group P2₁, while complex 2 crystallizes in the nonpolar space group P2₁2₁2₁. The chirality of both complexes is evidenced by the circular dichroism (CD) spectra. Both complexes show the characteristic photoluminescence of the Eu^III ion. In contrast to complex 2, complex 1 exhibits brilliant triboluminescence, an intense NLO property and ferroelectric behaviour at room temperature. The distinct chiral optical properties of complexes 1 and 2 originate from the differing crystal polarities.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

By using cyclohexane-1,2-diamine (chxn), Ni(ClO₄)₂⋅6H₂O and Na₃[Mo(CN)₈]⋅4H₂O, a 3D diamond-like polymer {[Ni^II(chxn)₂]₂[Mo^IV(CN)₈]⋅8H₂O}_n (1) was synthesised, whereas the reaction of chxn and Cu(ClO₄)₂⋅6H₂O with Na₃[M^V(CN)₈]⋅ 4H₂O (M=Mo, W) afforded two isomorphous graphite-like complexes {[Cu^II(chxn)₂]₃[Mo^V(CN)₈]₂⋅2H₂O}_n (2) and {[Cu^II(chxn)₂]₃[W^V(CN)₈]₂⋅2H₂O}_n (3). When the same synthetic procedure was employed, but replacing Na₃[Mo(CN)₈]⋅4H₂O by (Bu₃NH)₃[Mo(CN)₈]⋅4H₂O (Bu₃N=tributylamine), {[Cu^II(chxn)₂Mo^IV(CN)₈][Cu^II(chxn)₂]⋅ 2H₂O}_n (4) was obtained. Single-crystal X-ray diffraction analyses showed that the framework of 4 is similar to 2 and 3, except that a discrete [Cu(chxn)₂]²⁺ moiety in 4 possesses large channels of parallel adjacent layers. The experimental results showed that in this system, the diamond- or graphite-like framework was strongly influenced by the inducement of metal ions. The magnetic properties illustrate that the diamagnetic [Mo^IV(CN)₈] bridges mediate very weak antiferromagnetic coupling between the Ni^II ions in 1, but lead to the paramagnetic behaviour in 4 because [Mo^IV(CN)₈] weakly coordinates to the Cu^II ions. The magnetic investigations of 2 and 3 indicate the presence of ferromagnetic coupling between the Cu^II and W^V/Mo^V ions, and the more diffuse 5d orbitals lead to a stronger magnetic coupling interaction between the W^V and Cu^II ions than between the Mo^V and Cu^II ions.