The SmO n Coordination Polyhedra in Crystal Structures

Crystal-chemical analysis of all compounds studied to date and containing SmO _n coordination polyhedra was performed using the methods of Voronoi–Dirichlet polyhedra (VDP) and intersecting spheres. It was shown that the coordination number (CN) of Sm(III) atoms with respect to oxygen varies from 4 to 12 and the CN of Sm(II) is 5, 7, or 9. The Sm(III) Sm(II) transition was found to entail an increase in the VDP volume by, on average, 2.8 ų, whereas for a constant oxidation state of Sm, the VDP volume barely depends on the CN, although the Sm–O interatomic distances vary by 0.83 Å for Sm(III)-containing crystals and by 0.39 Å for Sm(II)-containing crystals. The results of analysis of the topology of [Sm _a O _b ] groups in the crystal structure are presented.     

The Coordination Polyhedra IrN n in Crystal Structures

Characteristics of the Voronoi–Dirichlet polyhedra were used to perform the crystal-chemical analysis of compounds containing iridium atoms surrounded by nitrogen atoms. The coordination polyhedra formed by Ir(III) atoms are always octahedra (IrN₆), whereas the Ir(2.5) and Ir(II) atoms occurring only in binuclear clusters form the IrN₄Ir ( is the vacancy) and IrN₅Ir quasi-octahedra. The parameters of the Voronoi–Dirichlet polyhedra allow one to estimate quantitatively the main stereochemical characteristics of iridium atoms, depending on their valence state.     

The Coordination Polyhedra OsN n in Crystal Structures

Characteristics of the Voronoi-Dirichlet polyhedra were used to perform the crystal-chemical analysis of 53 compounds containing osmium atoms surrounded by nitrogen atoms. Depending on the metal oxidation state, which varies from Os(II) to Os(VII), the coordination polyhedra formed by osmium atoms can be octahedra or trigonal prisms (OsN₆), square pyramids (OsN₄Os), tetrahedra (OsN₄), or triangles (OsN₃). The parameters of the Voronoi-Dirichlet polyhedra allow one to estimate quantitatively the main stereochemical features of Os atoms, depending on their oxidation state, and in controversial cases, they can be used to determine the oxidation state of osmium in the crystal structures.     

The EuOnCoordination Polyhedra in Crystal Structures

The Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were used to perform crystal-chemical analysis of the compounds studied to date containing EuO _n polyhedra. The Eu(III) and Eu(II) atoms were found to have coordination numbers (C.N.s) from 6 to 12 with respect to oxygen. The Eu(III) Eu(II) transition entails an increase in the VDP volume by, on average, 4 ų. For a constant valence state of europium, the VDP volume barely depends on the C.N., although the Eu–O interatomic distances change by 0.72 Å for Eu(III)-containing structures and by 0.59 Å for Eu(II)-containing structures.     

Coordination Polyhedra RhX6 (X = F,Cl, Br) in Crystal Structures

Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were used to perform crystal-chemical analyses of compounds containing complexes [Rh _a X _n ] ^z– (X = F, Cl, Br). It was found that, irrespective of oxidation number (+3, +4, or +5), rhodium atoms always exhibit the coordination number 6 with respect to the halogen atoms and have octahedral coordination. The influence of site symmetry and the valence state of Rh on the distortion of RhX₆ octahedra are considered. The electronic configuration of the Rh atoms is shown to influence the symmetry of their valence-force field within the crystal structure.     

Coordination Polyhedra RuXn (X = O,S, Se,Te) in Crystal Structures

Crystal-chemical analysis of 312 compounds containing complexes [Ru _a X _b ] ^z– (X = O, S, Se, Te) is performed using Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres. In most of these complexes, Ru atoms have coordination number (CN) 6 and form RuX₆ octahedra. However, only with respect to oxygen do the Ru(V)–Ru(VII) atoms exhibit CN 5 or 4 with trigonal-bipyramidal and tetrahedral coordination, respectively.The effect of the valence state of the Ru atoms on their stereochemistry is considered. The important role of the Ru–Ru interactions in the structure of the Ru(II)–Ru(V) compounds is established. As a result of the Ru–Ru interactions, the RuX₆ octahedra are linked through a face or common edge or give O₅Ru–RuO_- dimers in which every metal atom occupies one of the vertices of an octahedron formed by the neighboring Ru atom.The dependence of the Ru–Ru and Ru–O bond orders on their lengths is established on the basis of a crystal-structure analysis and the 18-electron rule.     

The IrX6 Coordination Polyhedra (X = F,Cl, Br) in Crystal Structures

The Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were used to perform crystal-chemical analysis of compounds containing [Ir _a X _b ] ^z– complexes (X = F, Cl, or Br). The coordination number of Ir atoms with respect to halogen atoms was found to be 6, irrespective of the oxidation state (III, IV, or V), and the coordination polyhedra formed by Ir were found to be always octahedra. The influence of the site symmetry and the valence state of the Ir atoms on the distortion of the IrX₆ octahedra is considered. It is shown that characteristics of the VDP of Ir atoms can be used for quantitative estimation of the crystal-chemical role of Ir atoms in the halide structures.     

Coordination Polyhedra OsXn(X = F, Cl, Br, I) in Crystal Structures

The Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were used to perform crystal-chemical analysis of compounds containing complexes [Os _a X _b ] ^z–(X = F, Cl, Br, I). Atoms of Os(V) at X = F and Cl, of Os(IV) at X = Cl, Br, and of Os(III) at X = Br were found to exhibit a coordination number of 6 with respect to the halogen atoms and to form OsX₆octahedra. The coordination polyhedra of Os(III) for X = Cl, I are square pyramids OsX₄. Each Os(III) atom forms one Os–Os bond; as a consequence, the OsBr₆octahedra share a face in forming Os₂Br^3– ₉complexes, while the OsX₄pyramids (X = Cl, I) dimerize to produce [X₄Os–OsX₄]^2–ions. The influence of the valence state of the Os atoms and of the nature of the halogen atoms on the composition and structure of the complexes formed and some characteristics of the coordination sphere of Os were considered.     

The Coordination Polyhedra PdX n (X = Cl,Br, I) in Crystal Structures

The Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were used to perform crystal-chemical analysis of 106 compounds containing palladium atoms surrounded by halogen atoms. Depending on the oxidation number (2 or 4), Pd atoms can bind 4 to 6 X atoms (X = Cl, Br, I) and form PdX _n coordination polyhedra shaped like octahedra or square pyramids (n = 6), square pyramids (n = 5), or squares (n = 4). A lone electron pair on Pd(II) was found on the basis of X-ray diffraction data. The influence of the palladium valence state on the key stereochemical features of palladium halide complexes is considered in terms of the 18-electron rule. The tendency of palladium atoms to Pd···H aghostic interactions was noted.     

The RhX n (X = S,Se, Te) Coordination Polyhedra in Crystal Structures

The Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were applied to crystal-chemical analysis of all known compounds whose structures contain rhodium atoms surrounded by chalcogen atoms. The influence of the rhodium valence state and the nature of the chalcogen on the main features of Rh stereochemistry are discussed. Rhodium atoms exhibit coordination numbers of 6, 5, or 4 with respect to S, Se, or Te atoms; in addition to the bonds with chalcogens, rhodium can form 1 to 4 bonds with metal atoms. The VDP volume for Rh(III), Rh(2.67), and Rh(II) atoms in selenides and tellurides very weakly depends on the valence state, whereas in the case of sulfides, the volume increases rather regularly with a decrease in the metal oxidation number from Rh(III) to Rh(I).     

The PtX n Coordination Polyhedra (X = S,Se, Te) in Crystal Structures

Using the Voronoi–Dirichlet partition procedure and the method of intersecting spheres, it is demonstrated that in the crystal structures of chalcogen-containing compounds, Pt(IV) atoms form only PtX₆ octahedra (X = S, Se, Te), whereas in the case of Pt(III) and Pt(II), square coordination by X atoms is typical. The Pt(II) atoms can also form PtX₅ square pyramids (X = S, Se), PtS₆ octahedra, and PtTe₃Pt₃ quasi-octahedra in which a platinum atom is located in the trans-position to each coordinated tellurium atom. It was found that Pt(II) atoms in the PtX₄ squares (X = S, Se), unlike square-coordinated Pt(III) atoms, can form one or two Pt–M bonds (M is a d metal) and 1 to 4 secondary Pt–Q bonds, where Q is an s metal or hydrogen. The main features of platinum stereochemistry depending on the metal valence state and coordination number (CN) and on the nature of the chalcogen atom were quantitatively characterized in terms of the Voronoi–Dirichlet polyhedra.     

The OsX n Coordination Polyhedra (X = O,S, Se,Te) in Crystal Structures

The Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were used to perform a crystal-chemical analysis of compounds whose structures contain Os atoms surrounded by chalcogen atoms. Depending on the valence state, Os atoms bind four to seven X atoms (X = O, S, Se, Te) forming OsX _n coordination polyhedra which can be tetrahedra (n = 4), trigonal bipyramids or square pyramids (n = 5), octahedra (n = 6), or pentagonal bipyramids (n = 7). In some compounds, pairs of OsO₆ octahedra share edges to form Os–Os bonds. The influence of the Os valence state and the nature of the chalcogen atom on the composition and structure of the [Os _a X _b ] groups is discussed. On the basis of analysis of the crystal-structural data from the standpoint of the 18-electron rule, dependences of the Os–O and Os–Os bond orders on the bond lengths are proposed.     

Interconversion of Highly Entangled Polyhedra into Concave Polyhedra by Nitrate-Induced Ternary Coordination

Entangled (M₃L₂)_n polyhedral complexes represent a unique class of supramolecular architectures that are stabilized by relatively weak metal–acetylene interactions in cooperation with conventional metal–pyridyl coordination. Counter-anion exchange of these complexes with a nitrate (NO₃⁻) ion triggered formal metal insertion between the metal centers, and a heteroleptic ternary coordination mode with acetylenic, pyridyl, and nitrate donors was generated on the metal centers. As a result, the main frameworks of the polyhedral complexes M₁₈L₁₂ and M₁₂L₈ were formally extended into a new series of concave polyhedra having the compositions M₂₁L₁₂ and M₁₃L₈, respectively. This transformation also resulted in the local disconnection of the highly entangled trifurcate topology of the framework, providing clues toward the skeletal editing of extended and complex three-dimensional (3D) architectures.     

次级键与晶体中锑(III)螯合物配位多面体研究

考虑立体活性孤对电子附近次级键配位原子的贡献,对文献报道的三十个氨基多羧酸锑(III)螯合物的晶体结构中配位多面体描述进行了全面的修正.配位多面体的几何构型指定采用了单位球内截多面体的两面角判据及其相关的ANVPDA程序.所有配位多面体几何构型的修正均得到了键价计算的有力支持.     

次级键与晶体中锑(III)螯合物配位多面体研究

考虑立体活性孤对电子附近次级键配位原子的贡献, 对文献报道的三十个氨基多羧酸锑(III)螯合物的晶体结构中配位多面体描述进行了全面的修正. 配位多面体的几何构型指定采用了单位球内截多面体的两面角判据及其相关的ANVPDA程序. 所有配位多面体几何构型的修正均得到了键价计算的有力支持.     

两个新型锌的配位聚合物的合成与晶体结构

本文以Zn(NO3)2.6H2O分别与1,3,5-均苯三甲酸(1,3,5-H3BTC)和2,5-噻吩二羧酸(2,5-H2TDC)通过水热/溶剂热反应合成了2个锌的配位聚合物[Zn3(OH)(BTC)2(C4N2H11)(H2O)]n(1)(C4N2H11=质子化的哌嗪)和[Zn(2,5-TDC)(i-PrOH)]n(2)。并对配位聚合物1和2进行了元素分析、FTIR和X-射线单晶结构解析等表征。X-射线单晶结构解析表明配位聚合物1和2的晶体均属于正交晶系,空间群分别为Pbca和P212121。化合物1中含有Zn3O结构单元,Zn3O结构单元通过BTC的连接构成1个层状结构,层状结构再通过堆积形成1个三维结构。化合物2中含有无机的Zn-O链。无机Zn-O链通过TDC配体与相邻的6个无机Zn-O链相连形成三维开放式的框架结构。     

两种异金属链状配位聚合物的合成和晶体结构

在甲醇溶液中,将K2NiL·H2O和M(OAC)2(M = Co,Zn)按1:1的摩尔比进行组装反应,得到了镍、钴和镍、锌两种异金属一维链状配位聚合物,其化学组成分别为{[Ni2Co2L2(H2O)2]·CH3OH·3H2O}n（1）和{[Ni2Zn2L2 (H2O)2]·2CH3OH·H2O}n（2）,（H4L=2-羟基-3-[(E)-({2-(2-羟基苯甲酰胺基)乙基}亚氨基)甲基]苯甲酸,OAC- = CH3COO-）。通过IR谱,元素分析的方法对其进行了表征,利用X-射线单晶衍射方法对其晶体结构进行了测定,结构分析表明：它们都是由不对称四核单元组成链状配位聚合物。     

Synthesis and Crystal Structures of Two Cadmium Coordination Chain Polymers

Hydrothermal reactions of cadmium precursors with 2, 2′‐bipyridine, fumaric acid or NaN₃ in basified aqueous solutions gave rise to two cadmium complexes [Cd(bipy)(fum)(H₂O)]_n ( 1 ), and [Cd(bipy)(μ_{1, 1}‐N₃)₂]_n ( 2 ) (fum = fumarate dianion), which were characterized by X‐ray crystallography. Complex [Cd(bipy)(fum)(H₂O)]_n ( 1 ) crystallizes in the orthorhombic system, space group Pbca, with a = 9.0488(8), b = 16.246(3), c = 19.810(4) Å, and Z = 8 while complex [Cd(bipy)(μ_{1, 1}‐N₃)₂]_n ( 2 ) in the monoclinic system, space group C2/c, with a = 12.378(3), b = 14.788(3), c = 6.6139(13) Å, β = 91.49(3)°, and Z = 4. The photoluminescence spectra for compounds 1 and 2 have also been studied.     

The Coordination Polyhedra BC<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript> in Crystal Structures

The method of intersecting spheres and Voronoi–Dirichlet polyhedra are used for crystal chemical analysis of 3817 structures comprising 4533 crystallographically nonequivalent sorts of boron atoms contained in BC_n coordination polyhedra. In these coordination polyhedra, boron has coordination numbers (CNs) from 2 to 6, the CN 4 being most typical. With increasing boron CN, the average B–C interatomic distances of the BC_n polyhedra increase by 0.01–0.13 Å, while the average radii of the spheres whose volumes are equal to the volumes of the Voronoi–Dirichlet polyhedra of boron atoms virtually do not vary within the determination error. The characteristic features of intermolecular contacts in the structures of two crystalline hydrates, Fe[B(CN)₄]₂ · 2H₂O and Fe[B(CN)₄]₃ · 6H₂O, are considered according to the method of Voronoi–Dirichlet molecular polyhedra.