Synthesis,crystal structure and thermal analysis of supramolecular architectures of copper(II)(2,2′-biimidazole) complexes using dicarboxylate as a coligand

Two new copper(II) complexes {[Cu(H₂biim)(H₂O)(suc)](H₂O)}_n (1) and {[Cu(H₂biim)₂(H₂O)][Cu(H₂biim)₂(glut)](glutH)(NO₃) · 2.5H₂O}_n (2) (H₂biim, 2,2′-biimidazole; suc, succinate dianion; glut, glutarate dianion) have been synthesized and characterized by single crystal X-ray diffraction study and thermal analysis. Complex 1 comprises of 1D zigzag coordination polymers, elongated along the crystallographic b-axis, connected through H-bonding and face-to-face π–π interactions to form a robust 3D network. Whereas complex 2 is built up of bischelated [Cu(II)(H₂biim)₂]²⁺ units, glutarate and nitrate anions and water molecules, held together through an extensive H-bonded system. The resulting 3D supramolecular architecture defines channels which are filled by lattice water molecules and disordered nitrate anions.     

New mercury(II) and silver(I) complexes containing NHC metallacrown ethers with the π-π stacking interactions

The oligoether-linked bis-benzimidazolium salt 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-^secbutyl)benzimidazolium-1-yl]iodide (H₂L¹ · I₂), 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-ethyl)benzimidazolium-1-yl]iodide (H₂L² · I₂) and 1,1′-[1,2-ethanediylbis(oxy-1,2-ethanediyl)]bis[(3-^secbutyl)benzimidazolium-1-yl]hexafluorophosphate (H₂L¹ · (PF₆)₂) and their three new mercury(II) and silver(I) complexes containing NHC metallacrown ethers, HgL¹ · (Hg₂ · I₆) (1), HgL² · I₂ (2) and AgL¹ · PF₆ (3) were prepared and characterized. In the packing diagrams of H₂L² · I₂, 1, 2 and 3 benzimidazole ring head-to-tail π-π stacking interactions are observed.     

Denting Nanospheres with a Short Peptide

Dented nanospheres show promising potential in drug delivery,nanomotors,etc.However,it is still challenging to prepare them by homopolymer self-assembly because of the strict structural requirements of the homopolymer.Herein,we propose a strategy for preparing dented nanospheres from homopolymers by co-assembly with a short peptide.They were co-assembled from poly(2-hydroxy-3-((4-(ethoxycarbonyl)phenyl)amino)propyl methacrylate) (PHBzoMA59) and (S)-2-((S)-2-((((gH-fluoren-9-yl)methoxy)carbonyl)amino)-3-phenylpro-panamido)-3-phenylpropanoic acid (Fmoc-FF-OH).PHBzoMA homopolymers can only self-assemble into nanospheres without dent,and the addition of a short peptide introduced hydrogen bonding and complementary π-π stacking interactions led to the final dented nanosphere morphology.The weight fractions of the short peptide can be adjusted to regulate the final morphology.It was confirmed that the radius of curvature of the dent on the surface was related to the organic bubble inside the protospheres prepared at critical aggregation concentration(CAC).The organic bubble can be adjusted by altering the kind of organic solvent and solution pH,which allowed control over the dented nanosphere dimension.The use of different organic solvents with various polarities allows adjustment of the interfacial tension,and hence the denting degree.This degree can also be controlled by manipulating the solution pH to (de)protonate the short peptide and homopolymer.Furthermore,the versatility of this method was highlighted by using a different homopolymer and the applicability of the resulting dented nanospheres was demonstrated by decoration with gold nanoparticles.Overall,this study provided important insights and a new simple strategy to prepare dented nanospheres in a controlled fashion.     

Crystal-Packing-Driven Enrichment of Atropoisomers

Crystal-packing forces can have a significant impact on the relative stabilities of different molecules and their conformations. The magnitude of such effects is, however, not yet well understood. Herein we show, that crystal packing can completely overrule the relative stabilities of different stereoisomers in solution. Heating of atropoisomers (i.e. “frozen-out” conformational isomers) in solution leads to complex mixtures. In contrast, solid-state heating selectively amplifies minor (<25 mole %) components of these solution-phase mixtures. We show that this heating strategy is successful for compounds with up to four rotationally hindered σ bonds, for which a single stereoisomer out of seven can be amplified selectively. Our results demonstrate that common supramolecular interactions—for example, [methyl⋅⋅⋅π] coordination and [C−H⋅⋅⋅O] hydrogen bonding—can readily invert the relative thermodynamic stabilities of different molecular conformations. These findings open up potential new avenues to control the folding of macromolecules.     

A Fullerene-Based Molecular Torsion Balance for Investigating Noncovalent Interactions at the C60 Surface

To investigate the nature and strength of noncovalent interactions at the fullerene surface, molecular torsion balances consisting of C₆₀ and organic moieties connected through a biphenyl linkage were synthesized. NMR and computational studies show that the unimolecular system remains in equilibrium between well-defined folded and unfolded conformers owing to restricted rotation around the biphenyl C−C bond. The energy differences between the two conformers depend on the substituents and is ascribed to differences in the intramolecular noncovalent interactions between the organic moieties and the fullerene surface. Fullerenes favor interacting with the π-faces of benzenes bearing electron-donating substituents. The correlation between the folding free energies and corresponding Hammett constants of the substituents in the arene-containing torsion balances reflects the contributions of the electrostatic interactions and dispersion force to face-to-face arene–fullerene interactions.     

二铜配合物[Cu2（NPG）4（4,4＇-bipy）2（H2O）2]·2H2O的合成、晶体结构及热性能分析

用溶液法合成了标题化合物[Cu2（NPG）4（4,4＇-bipy）2（H2O）2]·2H2O（HNPG=邻苯二甲酰甘氨酸4,4＇-bipy=4,4＇-联吡啶）,并通过X射线衍射对其单晶结构进行了测定.该结构属于三斜晶系,空间群P1,分子量Mr=1328.14,晶胞参数a=0.85512 （15）nm,b=1.7083 （3）nm,c=2.1115（4）nm,V=2.9996（9）nm3,Z=2,Dc=1.470g·cm-3,F（000）=1364.0.Cu（Ⅱ）配位形成变形的三角双锥构型,配合物的分子间和分子内氢键及π-π堆积将其拓展为三维结构,并对稳定晶体结构起着重要的作用.     

DV-Xα方法与电子光谱解析

本文介绍了第一原理量子化学DV Xα方法在电子光谱的理论计算方面的应用。在三个例子中分别详细讨论了过渡金属原子簇的紫外 可见吸收谱V/UV、X 射线光电子能谱XPS、和XANES的计算 ,应用于MoS4原子簇结构、Cu2 O/Cu表面与 2 氨基嘧啶相互作用模型、和MoS2 导带底部结构分析。根据在不同光谱分析的特点 ,采用相应的计算方案。电子光谱的解析除了在解释光谱现象外 ,能够进一步帮助了解分子或原子簇的结构。     

Novel Copper（Ⅱ） and Zinc（Ⅱ） 2-D Supramolecular Structures Based on Carboxylate and 1-Substitutedimidazole Mixed-ligands

Using the ligand bis(3-(1H-imidazol-1-yl)-1-phenylpropan-1-one) L, two novel com- plexes [CuL2(ph))]·H2O 1 and [ZnL2(tp)] 2 (ph = phthalic acid, tp = terephthalic acid) have been synthesized and their crystal structures were determined by single-crystal X-ray diffraction analysis. Crystal data for 1: triclinic, space group P1, a = 9.4300(17), b = 12.148(2), c = 13.721(2) , α = 109.620(2), β = 94.351(2), γ = 94.830(2)°, C32H30N4O7Cu, Mr = 646.14, V = 1466.2(4) 3, Z = 2, Dc = 1.464 g/cm3, μ(MoKα) = 0.801 mm-1, F(000) = 670, the final R = 0.0337 and wR = 0.0859 for 5122 observed reflections with I > 2σ(I). And those for 2: monoclinic, space group P2/n, a = 7.1866(11), b = 14.144(2), c = 14.407(2) , β = 101.427(2)°, C32H28N4O6Zn, Mr = 629.95, V = 1435.4(4) 3, Z = 2, Dc = 1.457 g/cm3, μ(MoKα) = 0.908 mm-1, F(000) = 652, the final R = 0.0438 and wR = 0.0821 for 2546 observed reflections with I > 2σ(I). In 1 and 2, ph or tp ligands bridge the six-coordinated copper(II) or four-coordinated zinc(II) ions forming 1D zigzag chains while L ligands act as the terminal monodentate ligand. It is noted that weak non-classical C–H···O plays the important and dominating roles in the formation of 2D supramolecular architectures of 1, but in 2 non-classical C–H···O and aromatic π-π stacking interactions are quite important and play dominant roles in the self-assembly of 2D supramolecular architectures.     

Fluoride-induced intermolecular excimer formation of bispyrenyl thioureas linked by polyethylene glycol chains

New bispyrenyl thioureas linked by polyethylene glycol (PEG) chains, L1-L3, and methoxy benzene pyrene thiourea, L4, were synthesized. Upon binding with F⁻ in CHCl₃, L1-L3 exhibited strong excimer emission bands (I_E) and weak monomer emission bands (I_M), while L4 displayed the same intensity of both bands. However, little or no change was observed in fluorescence spectra of L1 upon adding OH⁻, AcO⁻, BzO⁻, H₂PO₄⁻, Cl⁻, Br⁻, and I⁻. Therefore, only F⁻ induced the pyrene excimer formation. Job’s plots showed 1/1 or 2/2 complexation of L1 with F⁻. Ratios of I_E/I_M of L1·F⁻ complex were dependent on the concentration of L1, implying that the dimerization of L1 proceeded via the intermolecular excimer formation. Among L1-L4, L1 possessed the highest binding constant and sensitivity toward F⁻ implying the importance of the linking PEG chain. L1 was demonstrated to be an excellent probe for F⁻ in CHCl₃ with the detection limit as low as 46.2 μg/L.