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Template condensation of 2-acetylpyridineoxime with butyl ester of 1,3-propanediboronic acid in the presence of iron(II) affords a poorly separable mixture of complex products. Similar results were observed when Fe3+ ions were used for cross-linking in place of the diboronic acid. Prolonged crystallization of these mixtures gave crystals of perchlorate salts of a FeIIFeIIIFeII-trinuclear hexapyridineoximate cation and of an analogous FeIIFeIIFeII-intracomplex that crystallize with chloroform and dichloromethane solvent molecules, respectively. Both complexes were characterized by synchrotron single-crystal X-ray diffraction (XRD) experiments. The Fe–N distances of the two 'terminal' iron cations are virtually the same between these trinuclear complexes and unambiguously support assignments of oxidation number +2 and low-spin state (S = 0). The centers of the FeN6-coordination polyhedra adopt geometries resembling trigonal antiprisms with distortion angles φ of approximately 40°. The FeO6-coordination polyhedra possess an almost ideal Oh geometry with φ close to 60°. Each of these iron(II) or iron(III) µ3-metallocenters acts as a bifunctional Lewis acid that cross-links two pseudoclathrochelate entities, formed by the 'terminal' iron(II) ions, to give an almost linear (the corresponding intramolecular Fe(2)...Fe(1)...Fe(3) angles are close to 180°) helical cation or intracomplex. [ABSTRACT FROM AUTHOR]

Si(111) wafers patterned with an array of vertical 120 µm‐wide Al‐doped (1 × 1019 cm−3) p‐channels extending through the whole wafer were studied with the X‐ray double‐ and triple‐crystal diffraction technique in Bragg geometry with copper radiation. Reciprocal space maps (RSMs) of diffraction intensity far from the channels and near them were measured, and their non‐trivial shape was observed. The obtained experimental RSMs demonstrate high sensitivity to the structural distortions of the crystal in the subsurface layer owing to the influence of the surface on the elastic strain field in the channel. These features result from the small difference of the ionic radii of Si and Al, leading to the absence of misfit dislocations on the borders of the channel. Simulations of RSMs using the Takagi–Taupin dynamical diffraction theory taking into account the influence of the surface on the elastic strain field in the channel and the effect of the instrumental function were carried out. Finally, numerical RSM calculations showed that the proposed model of the surface effect on the elastic strain field in a semi‐infinite crystal with a vertical Si(Al) channel can be used to retrieve the information on the concentration of aluminium in the thermomigrated Si(Al) channel from the diffraction data obtained in the Bragg geometry. [ABSTRACT FROM AUTHOR]

Monopropargylamine iron(II) tris‐dioximate was easily prepared in a high yield using nucleophilic substitution of its monochloroclathrochelate precursor with propargylamine as a primary aliphatic amine N‐nucleophile in acetonitrile as a solvent. This complex with terminal C≡C group underwent a 1,3‐dipolar cycloaddition "click"‐reaction with ortho‐carborane‐1‐methylazide, thus giving a hybrid iron(II) carboranoclathrochelate with ortho‐carborane‐(12)‐[1,2,3]‐triazolmethylamine fragment in its ribbed substituent, the molecule of which contains two (i. e. clathrochelate and carborane) terminal cages. These complexes were characterized using elemental analysis, MALDI‐TOF mass, IR, UV‐Vis, 1H, 1H{11B}, 11B, 11B{1H}, 19F{1H} and 13C{1H} NMR spectra, and by single crystal X‐ray diffraction as well. [ABSTRACT FROM AUTHOR]

Graphical abstract Tris-glyoximate and tris-dichloroglyoximate iron(II) clathrochelates with apical donor pyridyl groups were obtained via template condensation and characterized by single crystal XRD. Their ligand aspect ratios were compared with those for the aliphatic macrobicyclic tris-dioximates. Abstract Tris-glyoximate and tris-dichloroglyoximate iron(II) clathrochelates with apical pyridyl groups were obtained through one-pot template condensation of the corresponding α-dioxime with 3- or 4-pyridylboronic acids on the iron(II) ion as a matrix under vigorous reaction conditions using the boiling CF 3 COOH as a solvent. The initially formed mixtures of mono- and diprotonated clathrochelate species were converted into the target macrobicyclic intracomplexes under basic conditions. These complexes were characterized using elemental analysis, MALDI-TOF mass spectrometry, IR, UV–Vis, 1H and 13C NMR spectroscopies, and by single crystal X-ray diffraction as well. In their molecules, the encapsulated iron(II) ion is situated in the center of its FeN 6 -coordination polyhedron. The geometry of all the FeN 6 -coordination polyhedra is intermediate between a trigonal prism and a trigonal antiprism with the average distortion angles φ from 16.7 to 17.7°. Their heights h fall from 2.36 to 2.38 Å and the averaged bite angles α vary in a narrow range 78.2–78.4°. Characteristic feature of the 3- and 4-pyridylboron-capped glyoximate clathrochelate molecules, as compared with their aliphatic and aromatic analogs, is shortening of the chelate C C bonds from 1.45 to 1.42 Å. Comparison of the values of a ligand aspect ratio for the obtained new pyridyl-terminated iron(II) clathrochelates with those for their known aliphatic tris-dioximate analogs was performed. [ABSTRACT FROM AUTHOR]

Crystallization of the 2-thiopheneboron-capped tris-dimethylglyoximate cobalt(II) clathrochelate from a crude chloroform unexpectedly gave single crystals of CoIIICoIICoIII bis-clathrochelate: in this complex, two macrobicyclic frameworks are linked by bridging Co2+ ion. The N–O distances in the donor oxime groups of these X-rayed mono- and bis-clathrochelates are governed by the nature of their capping groups (1.38 and 1.31Å for the boron and cobalt “caps”). The average Co–N distances of the CoN6 -coordination polyhedra of an encapsulated cobalt ion strongly depend on its oxidation states (1.97 and 1.91Å for the cobalt(II) and cobalt(III) ions). Co2+ ion is shifted from the center of this polyhedron by 0.2Å due to the Jahn–Teller distortion, whereas Co3+ ions occupy the centers of the ligands' cavities. The geometry of the CoIIN6 and CoIIIN6 polyhedra is substantially different: due to the rigidity of the macrobicyclic tris-dioximate ligand and high Shannon radius of Co2+ ion, the corresponding clathrochelate has a TP geometry, whereas the smaller Co3+ ion causes the rotational–translation shortening of the CoN6 polyhedron with a decrease in its height h from 2.45 to 2.24Å. The photochemical experiments with irradiation of a chloroform solution of the initial clathrochelate showed that the most probable pathway to the bis-clathrochelate includes photoinitiated radical oxidation of chloroform with air oxygen. The reactive species formed cause opening, rearrangement and re-capping of the macrobicyclic framework affording a new CoIIICoIICoIII bis-clathrochelate. [ABSTRACT FROM AUTHOR]

Kinetics and thermodynamics of the template synthesis and of the acidic decomposition of the methylboron-capped iron(II) tris-1,2-dioximates—the clathrochelate derivatives of six (nioxime)- and eight (octoxime)-membered alicyclic ligand synthons—were compared. In the case of a macrobicyclic iron(II) tris-nioximate, the plausible pathway of its formation contains a rate-determining stage and includes a reversible formation of an almost trigonal-antiprismatic (TAP) protonated tris-complex, followed by its monodeprotonation and addition of CH3B(OH)2. Thus, the formed TAP intermediate undergoes a multistep rate-determining stage of double cyclization with the elimination of two water molecules accompanied by a structural rearrangement, thus giving an almost trigonal-prismatic (TP) iron(FII) semiclathrochelate. It easily undergoes a cross-linking with CH3B(OH)2, resulting in the elimination of H+ ion and in the formation of a macrobicyclic structure. In contrast, the analogous scheme for its macrobicyclic tris-octoximate analog was found to contain up to three initial stages affecting the overall synthesis reaction rate. The rates of acidic decomposition of the above clathrochelates were found to be also affected by the nature of their ribbed substituents. Therefore, the single crystal XRD experiments were performed in order to explain these results. The difference in the kinetic schemes of a formation of the boron-capped iron(II) tris-nioximates and tris-octoximates is explained by necessity of the substantial changes in a geometry of the latter ligand synthon, caused by its coordination to the iron(II) ion, due to both the higher distortion of the FeN6-coordination polyhedra, and the intramolecular sterical clashes in the molecules of the macrobicyclic iron(II) tris-octoximates. [ABSTRACT FROM AUTHOR]

One-pot template condensation of glyoxime with the corresponding functionalized phenylboronic acids on an iron(II) ion as a matrix afforded 3- and 4-substituted phenylboron-capped tris-glyoximate iron(II) clathrochelates with terminal amine, formyl (acetal) and vinyl groups; those with acetal groups were converted into the formyl-terminated cage complexes using H + -catalyzed hydrolysis. The complexes obtained were characterized using elemental analysis, MALDI-TOF mass spectrometry, IR, UV–Vis, 1 H and 13 C NMR spectroscopies, and by single crystal X-ray diffraction (for three of these clathrochelates). Their molecules possess a geometry intermediate between a trigonal prism (TP) and a trigonal antiprism (TAP) and the bite angles α remain almost constant being in the range 77–79°, whereas the heights h of FeN 6 -coordination polyhedra depend on the distortion angle φ values (from 12.2 to 20.7°) thus being in the range 2.36–2.37 Å. An encapsulated iron(II) ion is situated almost in the centre of cage frameworks and the average chelate C C bonds in these tris-glyoximate frameworks are substantially shorter than those for their aliphatic and aromatic analogs. The crystal packings are governed by weak supramolecular hydrophobic interactions and an absence of the steric hindrances between the ribbed substituents (hydrogen atoms) allowed to form intermolecular π…π interactions. As follows from single crystal X-ray diffraction data, the synthesized macrobicyclic tris-glyoximates with reactive terminal groups, which the macrobicyclic molecules contain no bulky ribbed substituents, have large ligand aspect ratio and, therefore, they seem to be promising syntones and building blocks for preparation of covalent (including imine and amine) and coordination metallomacrocycles, MOFs and cages (capsules) with big voids and cavities as hosts, suitable for inclusion of various organic and inorganic guests. [ABSTRACT FROM AUTHOR]

Self-assembly of monohexadecylboron-capped zinc, cobalt, iron and manganese(II) tris-pyrazoloximate pseudoclathrochelates was performed using one-pot template condensation of 2-acetylpyrazole oxime with n -hexadecylboronic acid as a capping Lewis-acidic agent on the corresponding metal ion as a matrix. Hydrogen atoms of three terminal pyrazolyl NH groups of three pyrazoloxime synthons form a pseudomacrobicyclic ligand through their hydrogen bonding with a chloride counterion Cl − … (HN) 3 , thus allowing an encapsulation of the corresponding metal ion. The complexes obtained were characterized using elemental analysis, MALDI-TOF mass spectrometry, IR, UV-Vis-NIR, 57 Fe Mössbauer (for the iron complex), 1 H and 13 C NMR spectroscopy, as well as by SQUID magnetometry. The structure of the complexes synthesized was also confirmed by single crystal X-ray diffraction analysis of the zinc(II) pseudoclathrochelate. Its pseudocaged zinc(II) ion is located almost in the center of ZnN 6 -coordination polyhedron, which adopts a trigonal prismatic geometry with a very low distortion angle. As follows from variable-temperature magnetometry data, the χT values for manganese and iron(II) pseudoclathrochelates in the temperature range 50–300 К are close to theoretical pure high-spin values without of orbital contribution. 1 H and 13 C NMR chemical shifts of their pyrazoloximate nuclei reach to some hundreds of ppm, while those chemical shifts of the normal hexadecyl chain's nuclei, on the distance of more than five chemical bonds from the pseudoencapsulated paramagnetic metal ion, are close to those for the diamagnetic zinc(II) pseudoclathrochelate. This is indicative of the contact nature of thus induced paramagnetic shifts, as well as a weak pseudocontact contribution. [ABSTRACT FROM AUTHOR]