Crystal Structure and Spectroscopic Properties of trans‐Dibromidobis(propane‐1, 3‐diamine)chromium(III) Perchlorate

The structure of trans‐[Cr(tn)₂Br₂]ClO₄ (tn = propane‐1, 3‐diamine) has been determined by a single‐crystal X‐ray diffraction study at 100 K. The complex crystallizes in the space group P$\bar{1}$ of the triclinic system with two mononuclear formula units in a cell of dimensions a = 6.8220(4), b = 8.86199(9), c = 12.6644(8) Å and α = 77.859(7)°, β = 81.765(6)°, and γ = 77.764(7)°. The chromium atom is in a slightly distorted octahedral environment coordinated by four nitrogen atoms of two tn ligands and two bromine atoms in trans positions. The two six‐membered chelate rings in the complex cations are oriented in an anti chair‐chair conformation with respect to each other. The mean Cr–N(tn) and Cr–Br bonds are 2.093(3) and 2.4681(4) Å, respectively. The crystal packing is stabilized by hydrogen bonds. The infrared and electronic absorption spectral properties are consistent with the result of X‐ray crystallography. It is confirmed that the nitrogen atoms of the tn ligand are strong σ‐donors, but the bromido ligands have weak σ‐ and π‐donor properties toward the chromium(III) ion.     

Synthesis,Crystal Structure and Spectroscopic Properties of [2,13‐Bis(1‐naphthalenylmethyl)‐5,16‐dimethyl‐2,6,13,17‐tetraazatricyclo(14,4,01.18,07.12)docosane]copper(II) Diperchlorate Acetonitrile Disolvate

The N‐functionalized macrocyclic ligand 2,13‐bis(1‐naphthalenylmethyl)‐5,16‐dimethyl‐2,6,13,17‐tetraazatricyclo(14,4,0^1.18,0^7.12)docosane (L³) and its copper(II) complex were prepared. The crystal structure of [Cu(L³)](ClO₄)₂·2CH₃CN was determined by single‐crystal X‐ray diffraction at 150 K. The copper atom, which lies on an inversion centre, has a square planar arrangement and the complex adopts a stable trans‐III configuration. The longer distance [2.081(2) Å] for Cu–N(tertiary) compared to 2.030(3) Å for Cu–N(secondary) may be due to the steric effect of the attached naphthalenylmethyl group on the tertiary nitrogen atom. Two perchlorate ions are weakly attached to copper in axial sites and are further connected to the ligand of the cation through NH ··· O hydrogen bonds [N ··· O 3.098 Å]. IR and UV/Vis spectroscopic properties are also described.     

分子光谱法研究铝酞菁与牛血红蛋白的相互作用

利用紫外可见吸收光谱和荧光光谱研究了在生理pH条件下铝酞菁与牛血红蛋白(BHb)的相互作用.实验结果表明:铝酞菁分子与BHb发生反应生成基态复合物,导致BHb内源荧光的猝灭,该猝灭属于静态猝灭.测定了不同温度下该反应的表观结合常数、结合位点数及结合热力学参数,热力学参数的变化表明铝酞菁与BHb之间以静电和疏水作用力为主;根据Frster能量转移理论,测得供体与受体间结合距离r和能量转移效率E;并用同步荧光光谱法探讨了铝酞菁对BHb构象的影响.     

Synthesis and Spectroscopic Properties of Fused‐Ring‐Expanded Aza‐Boradiazaindacenes

A series of fused‐ring‐expanded aza‐boradiazaindacene (aza‐BODIPY) dyes have been synthesized by reacting arylmagnesium bromides with phthalonitriles or naphthalenedicarbonitriles. An analysis of the structure–property relationships has been carried out based on X‐ray crystallography, optical spectroscopy, and theoretical calculations. Benzo and 1,2‐naphtho‐fused 3,5‐diaryl aza‐BODIPY dyes display markedly red shifted absorption and emission bands in the near‐IR region (>700 nm) due to changes in the energies of the frontier MOs relative to those of 1,3,5,7‐tetraaryl aza‐BODIPYs. Only one 1,2‐naphtho‐fused aza‐BODIPY of the three possible isomers is formed due to steric effects, and 2,3‐naphtho‐fused compounds could not be characterized because the final BF₂ complexes are unstable in solution. The incorporation of a  N(CH₃)₂ group at the para‐positions of a benzo‐fused 3,5‐diaryl aza‐BODIPY quenches the fluorescence in polar solvents and results in a ratiometric pH response, which could be used in future practical applications as an NIR “turn‐on” fluorescence sensor.     

Excited‐State Aromaticity of Gold(III) Hexaphyrins and Metalation Effect Investigated by Time‐Resolved Electronic and Vibrational Spectroscopy

Expanded porphyrins with appropriate metalation provide an excellent opportunity to study excited‐state aromaticity. The coordinated metal allows the excited‐state aromaticity in the triplet state to be detected through the heavy‐atom effect, but other metalation effects on the excited‐state aromaticity were ambiguous. Herein, the excited‐state aromaticity of gold(III) hexaphyrins through the relaxation dynamics was revealed via electronic and vibrational spectroscopy. The S_Q states of gold [26]‐ and [28]‐hexaphyrins showed interconvertible absorption and IR spectra with those of counterparts in the ground‐state, indicating aromaticity reversal. Furthermore, while the T₁ states of gold [28]‐hexaphyrins also exhibited reversed aromaticity according to Baird's rule, the ligand‐to‐metal charge‐transfer state of gold [26]‐hexaphyrins contributed by the gold metal showed non‐aromatic features arising from the odd‐number of π‐electrons.     

Synthesis,Spectroscopic Characterization,and Oxidative C–C Coupling in New Copper(II) Salicylaldiminates Containing Sterically Hindered Phenol

New bis[N‐(2,6‐di‐tert‐butyl‐1‐hydroxyphenyl)salicylideneminato]copper(II) complexes bearing HO and CH₃O substituents on the salicyaldehyde moiety were prepared, and have been characterized by elemental analyses, IR, UV/Vis, ESR spectroscopy, and magnetic moments. It has been found that in the synthesis of CH₃O substituted complexes unlike HO bearing, the oxidative C–C coupling of coordinated salicylaldimine ligands take place. It has been suggested that the intermolecular H‐bonding is a dominant factor in controlling of oxidative C–C coupling conversion. The powder ESR spectra of CH₃O substituted compounds unlike of HO are typical of a triplet state Cu^II dimers with a half‐field forbidden (δM = ± 2) and the allowed (δM = ± 1) transitions at 300 and 113 K.     

New Saccharinato/Ammonia Complexes of Nickel(II) and Zinc(II). A Structural and Spectroscopic Study

Two new saccharinate/NH₃ complexes of composition [Ni(sac)₂(NH₃)₄] and [Zn(sac)₂(NH₃)₂] were obtained and their crystal structures determined by single crystal X‐ray diffractometry. The elongated octahedral Ni^II complex crystallizes in the monoclinic P2₁/c space group with Z = 2 whereas the tetrahedral Zn^II complex is triclinic (space group and Z = 2). For [Ni(sac)₂(NH₃)₄] the magnetic moment and electron absorption spectrum were obtained and discussed. The infrared spectra of both complexes were also recorded and briefly commented.     

A New 3D Manganese(II) Coordination Polymer with 4,4‐Dicarboxy‐2,2′‐bipyridine and 1,10‐Phenanthroline: Synthesis,Structural, and Magnetic Properties

A new 3D Mn^II metal‐organic framework compound {Mn(phen)(dcbp)}_n (H₂dcbp = 4,4‐dicarboxy‐2,2′‐bipyridine, phen = 1,10‐phenanthroline) was isolated under hydrothermal conditions and structurally characterized. In the compound, the dcbp ligand is deprotonated to give a neutral species (metal:ligand with 1:1 stoichiometry). Along the c axis, the neighboring Mn^II ions are linked by two carboxylate bridges in µ₂‐coordinating mode to generate a 1D zigzag chain, and these chains are interlinked by dicarboxylate groups of long dcbp ligands to generate a 3D (4,4)‐connected structure with the (4².8⁴) net topology. IR and UV/Vis spectroscopy and variable temperature magnetic susceptibility measurements were made, which indicated weak antiferromagnetic interactions between the Mn^II ions of the compound.     

Synthesis and Optical Properties of Water‐Soluble Polyglycerol‐Dendronized Rylene Bisimide Dyes

Four new water‐soluble polyglycerol‐dendronized perylene, terrylene, and quaterrylene bisimides have been synthesized and characterized with respect to their optical properties in polar organic solvents and water by using UV/Vis and fluorescence spectroscopy. All of these dyes were highly soluble in water, but the size of the chosen polyglycerol dendron was only sufficient to completely suppress dye aggregation for the core‐unsubstituted perylene derivative. Their high solubility in water and their absorption and emission wavelengths up to the NIR region make the core‐unsubstituted perylene and terrylene bisimides ideal candidates for applications in bioimaging, whilst the lack of fluorescence for quaterrylene bisimide in all polar solvents does not warrant further investigation of this chromophore in fluorescence and imaging applications. Likewise, tuning of the emission of rylene bisimides towards longer wavelengths by employing electron‐donating bay substituents is not a promising strategy, owing to the lower fluorescence quantum yields in polar solvents and, in particular, in water.     

Synthesis,Crystal Structure,and Characterization of Two Novel One‐ and Two‐Dimensionally Polymeric Copper(II) Phosphonoacetates

Blue single crystals of Cu[μ₂‐OOC(CH₂)PO₃H] · 2H₂O ( 1 ) and Cu_1.5[μ₃‐OOC(CH₂)PO₃] · 5H₂O ( 2 ) were prepared in aqueous solution. In compound 1 [space group C2/c (no. 15) with a = 1623.3(2), b = 624.0(1), c = 1495.5(2) pm, β = 122.45(1)°], Cu is coordinated by three oxygen atoms stemming from the hydrogenphosphonoacetate dianion and three water molecules to form a distorted octahedron. The Cu–O bonds range from 190.4(3) to 278.5(3) pm. The connection between the Cu²⁺ cations and the hydrogenphosphonoacetate dianions leads to a two‐dimensional structure with layers parallel to (101). The layers are linked by hydrogen bonds. In compound 2 [space group P1 (no. 2) with a = 608.2(1), b = 800.1(1), c = 1083.6(1) pm, α = 94.98(1)°, β = 105.71(1)°, γ = 109.84(1)°], two crystallographically independent Cu²⁺ cations are coordinated in a square pyramidal and an octahedral fashion, respectively. The Cu–O bonds range from 192.9(2) to 237.2(2) pm. The coordination of the phosphonoacetate trianion to Cu(1) results in infinite polyanionic chains parallel to [100] with a composition of {Cu(H₂O)[OOC(CH₂)PO₃]}_n^n–. Hydrated Cu(2) cations are accommodated between the chains as counterions. 1 and 2 show structural features of cation exchangers. Magnetic measurements reveal a paramagnetic Curie‐Weiss behavior. Compound 2 shows antiferromagnetic coupling between Cu²⁺ ions due to a super‐superexchange coupling. The UV/Vis spectra of 1 suggest three d–d transition bands at 763 nm (²B₁ → ²E), 878 nm (²B₁ → ²B₂), and 1061 nm (²B₁ → ²A₁). Thermoanalytical investigations in air show that compound 1 is stable up to 165 °C, whereas decomposition of 2 begins at 63 °C.     

Copper(II) Supramolecular Complex: Synthesis,Crystal Structure,and Electrochemical Property

A novel complex {Cu(Bobb)₂](pic)₂}₂ [pic = picrate anion, Bobb = 1,3‐bis(1‐benzylbenzimidazol‐2‐yl)‐2‐oxopropane] was synthesized and characterized by means of elemental analyses and electrical conductivity. The crystal structure of the copper complex has been determined by single‐crystal X‐ray diffraction. A study of the electrochemistry of the title compound was carried out by using cyclic voltammetry. It revealed that the copper complex exhibits a quasi‐reversible redox process. The X‐ray structure of the above complex shows that the unit cell consists of two centrosymmetric, crystallographically independent molecules, in which the copper(II) ions have the same coordination environment and should be described as distorted octahedron. The complex is formed of { ··· Cu(2) ··· Cu(1) ··· Cu(1) ··· }_∞ supramolecular configuration by π ··· π stacking interactions between the benzimidazole rings. The complex was also identified by IR and electronic spectroscopy.     

9,10‐Diaminoanthracenes Revisited: The Influence of N‐Substituents on Their Electronic States

The electronic and molecular structures of 9,10‐diamino‐substituted anthracenes with different N‐substituents have been re‐examined. In particular, different N‐substituents influence both the electronic and molecular structures of the oxidized species of 9,10‐diaminoanthracenes. The anthrylene moiety of 9,10‐bis(N,N‐di(p‐anisyl)amino)anthracene retains its planarity during the course of two successive one‐electron oxidations, whereas 9,10‐bis(N,N‐dimethylamino)anthracene and 9,10‐bis(N‐p‐anisyl‐N‐methylamino)anthracene undergo a substantial structural change to a butterfly‐like structure through a two‐electron oxidation process. The structural changes observed for the oxidized states are ascribed to significant differences in the frontier molecular orbitals of the above‐mentioned three kinds of 9,10‐diaminoanthracenes due to different extents of mixing between the amine‐localized and anthrylene‐localized orbitals.