Anton S. Nizovtsev

We report a new concept to lower the melting temperature (T _m ) of inorganic‐organic hybrid adamantane‐based cluster compounds by forming unprecedented eutectic cluster mixtures with organic adamantane derivatives. Blending of clusters of the type [( p ‐MeC ₆ H ₄ Si(CH ₂ SnPhE) ₃ ] (E = S, Se, Te) with (3‐F‐4‐Me‐C ₆ H ₃ ) ₃ Ad, (3‐F‐4‐Me‐Ph) ₄ Ad, and (4‐MeO‐C ₆ H ₄ ) ₄ Ad was achieved by mechanical mixing and led to decreased T _m while retaining the components’ chemical identity. Such adamantane‐type compounds are known to exhibit strongly non‐linear optical properties: upon irradiation with a continuous wave (CW) laser diode, they respond either by second‐harmonic generation (SHG), if being crystalline, or by white‐light generation (WLG) with corresponding broadband emission, if being intrinsically amorphous or transformed into a glassy state. Herein, we show that this feature is preserved in the eutectic mixtures, hence, we can report superior properties of these cluster‐based materials that combine favorable nonlinear optical behavior with lowered T _m , which facilitates their processing for future use.

The interplay between π-electron conjugation and molecular geometry has been a central focus in the development of modern hydrocarbon research. Herein, we report the on-surface synthesis and characterization of the nonplanar, π-extended, nitrogen-doped quintulene C85N5 on a Au(111) surface. The as-synthesized C85N5 adopts a convex geometry, which can be inverted to a concave geometry by single-molecule manipulation. In its convex conformation, C85N5 may coordinate a gold atom within its central pore, forming an Au-C85N5 complex through interactions with the pyridinic nitrogen atoms. The structures and electronic properties of these cycloarenes are elucidated by noncontact atomic force microscopy (nc-AFM), scanning tunneling microscopy and spectroscopy (STM/STS), and density functional theory (DFT) calculations. Our results highlight that on-surface synthesis enables the atomically precise generation of curved (hetero)nanographenes and their metal complexes. Despite the inherent challenges of the nonplanar π-system, both geometric and electronic features can be characterized in detail, and controlled manipulation by scanning probe techniques is feasible.

Multiplex imaging in the second near‐infrared window (NIR‐II, 1000–1700 nm) provides exciting opportunities for more precise understanding of biological processes and more accurate diagnosis of diseases by enabling real‐time acquisition of images with improved contrast and spatial resolution in deeper tissues. Today, the number of imaging agents suitable for this modality remains very scarce. In this work, we have synthesized and fully characterized, including theoretical calculations, a series of dimeric Ln ^III /Ga ^III metallacrowns bearing Ru ^II polypyridyl complexes, LnRu‐3 (Ln=Y ^III , Yb ^III , Nd ^III , Er ^III ). Relaxed structures of YRu‐3 in the ground and the excited electronic states have been calculated using dispersion‐corrected density functional theory methods. Detailed photophysical studies of LnRu‐3 have demonstrated that characteristic emission signals of Yb ^III , Nd ^III and Er ^III in the NIR‐II range can be sensitized upon excitation in the visible range through Ru ^II ‐centered metal‐to‐ligand charge transfer (MLCT) states. We have also showed that these NIR‐II signals are unambiguously detected in an imaging experiment using capillaries and biological tissue‐mimicking phantoms. This work opens unprecedented perspectives for NIR‐II multiplex imaging using Ln ^III ‐based molecular compounds.

Multiplex imaging in the second near‐infrared window (NIR‐II, 1000–1700 nm) provides exciting opportunities for more precise understanding of biological processes and more accurate diagnosis of diseases by enabling real‐time acquisition of images with improved contrast and spatial resolution in deeper tissues. Today, the number of imaging agents suitable for this modality remains very scarce. In this work, we have synthesized and fully characterized, including theoretical calculations, a series of dimeric Ln ^III /Ga ^III metallacrowns bearing Ru ^II polypyridyl complexes, LnRu‐3 (Ln=Y ^III , Yb ^III , Nd ^III , Er ^III ). Relaxed structures of YRu‐3 in the ground and the excited electronic states have been calculated using dispersion‐corrected density functional theory methods. Detailed photophysical studies of LnRu‐3 have demonstrated that characteristic emission signals of Yb ^III , Nd ^III and Er ^III in the NIR‐II range can be sensitized upon excitation in the visible range through Ru ^II ‐centered metal‐to‐ligand charge transfer (MLCT) states. We have also showed that these NIR‐II signals are unambiguously detected in an imaging experiment using capillaries and biological tissue‐mimicking phantoms. This work opens unprecedented perspectives for NIR‐II multiplex imaging using Ln ^III ‐based molecular compounds.

Electronic structures of four tetrafluoro derivatives of zinc(II) phthalocyanine with substituents at non-peripheral positions as well as their valence electronically excited singlet states are calculated by density functional theory methods. For the structural isomers under study intense electronic transitions to which characteristic Q and B absorption bands correspond are analyzed. The UV-Vis absorption spectrum of the considered compound is modeled using the calculated data for the relative thermodynamic stability of the isomers.

Structural parameters of four complexes formed as a result of the interaction of carbon monoxide with cobalt(II), nickel(II), copper(II), and zinc(II) phthalocyanines are calculated by density functional theory methods. Changes in molecular and electronic structures caused by CO adsorption are analyzed for 3d-metal phthalocyanines studied. The mentioned gas is found to form the strongest complex with cobalt(II) phthalocyanine while the greatest charge transfer occurs during adsorption of carbon monoxide on the surface of the zinc(II) phthalocyanine molecule.

С применением методов теории функционала плотности рассчитаны структурные параметры четырёх комплексов, образующихся в результате взаимодействия монооксида углерода с фталоцианинами кобальта(II), никеля(II), меди(II) и цинка(II). Для исследуемых фталоцианинов 3d‑металлов проанализированы изменения молекулярной и электронной структуры, вызванные адсорбцией CO. Установлено, что рассматриваемый газ образует наиболее прочный комплекс с фталоцианином кобальта(II), а наибольший перенос заряда происходит при адсорбции монооксида углерода на поверхности молекулы фталоцианина цинка(II).

Interatomic interactions in four zinc(II) phthalocyanine tetrafluoro derivatives with substituents in non-peripheral positions are analyzed by quantum chemistry methods. Regions of non-covalent interactions are discovered between H⋯N and F⋯N contacts; the energies of interaction between the corresponding atoms are determined. It is shown that the relative energy of considered compounds increases with the increasing number of short F⋯F contacts.

Porous metal–organic framework [Zn₂(ttdc)₂(bpy)] (1) based on thieno [3,2-b]thiophenedicarboxylate (ttdc) was synthesized and characterized. The structure contains intersected zig-zag channels with an average aperture of 4 × 6 Å and a 49% (v/v) guest-accessible pore volume. Gas adsorption studies confirmed the microporous nature of 1 with a specific surface area (BET model) of 952 m²·g^–1 and a pore volume of 0.37 cm³·g^–1. Extensive CO₂, N₂, O₂, CO, CH₄, C₂H₂, C₂H₄ and C₂H₆ gas adsorption experiments at 273 K and 298 K were carried out, which revealed the great adsorption selectivity of C₂H₆ over CH₄ (IAST selectivity factor 14.8 at 298 K). The sulfur-rich ligands and double framework interpenetration in 1 result in a dense decoration of the inner surface by thiophene heterocyclic moieties, which are known to be effective secondary adsorption sites for carbon dioxide. As a result, remarkable CO₂ adsorption selectivities were obtained for CO₂/CH₄ (11.7) and CO₂/N₂ (27.2 for CO₂:N₂ = 1:1, 56.4 for CO₂:N₂ = 15:85 gas mixtures). The computational DFT calculations revealed the decisive role of the sulfur-containing heterocycle moieties in the adsorption of CO₂ and C₂H₆. High CO₂ adsorption selectivity values and a relatively low isosteric heat of CO₂ adsorption (31.4 kJ·mol^–1) make the porous material 1 a promising candidate for practical separation of biogas as well as for CO₂ sequestration from flue gas or natural gas.