Photochemical properties and structures ofN-amino andN-azomethine derivatives of 2,4,6-triphenylpyridinium perchlorates

The molecular structures of the initial compounds and the products of photocyclization involving amino and azomethine groups in perchlorates ofN-amino (1) andN-azomethine (2) derivatives of 2,4,6-triphenylpyridinium cations were studied. Cations1 and2 have an essentially non-coplanar arrangement of the -Ph rings, and the product of photocyclization of2, cation3, is characterized by a flattened structure. It was found that the orientation of the lone electron pair of the N atom with respect to one of the planes of the -Ph rings in molecule1 is more favorable for monocyclization involving the amino group. The structure of molecule2 allows two routes of the photoreaction,viz., O N proton transfer and monocyclization with an -Ph ring. However, the structural features of molecule2 are more favorable for photocyclization.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 296–301, February, 1995.     

Nontrivial structural organization of pivalate complexes with the fragment {Fe2Li(μ3-O)}

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Borderline of hydrogen bonding of silanols

Two new silanols bearing very bulky silyl groups, (i-Pr₃ Si)₃SiOH and (t − BuMe₂Si)₃SiOH were prepared by peracidoxidation of their respective silanes. The X − ray crystallographic analysis revealed that (t − BuMe₂Si)₃ SiOH forms a dimeric structure with hydrogen bonding, while (i − Pr₃ Si)₃ SiOH exists as a monomer in the crystal. The effects of the size of the substituents as well as the reactivity of these silanols are discussed.     

Crystal Structure and Molecular Absolute Configuration of （＋）－Isocedranol （C_（15）H_（26）O）

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Tetrabutylammonium Salts of Ruthenium(II) Nitroso Complexes

The paper describes synthesis of (nBu₄N)₂[RuNOCl₅](I), (nBu₄N)₂[RuNOCl₄OH](II), (nBu₄N)₂×[RuNOCl₄OH]·6H₂O (III), and (nBu₄N)₂[RuNOCl₅]· 2(nBu₄N)₂[RuNOCl₄(H₂O)]·2H₂O (IV). The complexes were studied by IR spectroscopy and powder Xray and crystal Xray analyses. The structures are built up of [RuNOCl₅]^2- (I, IV), [RuNOCl₄OH]^2- (II, III), and [RuNOCl₄(H₂O)]^- (IV) complex anions, (nBu₄N)⁺ cations, and crystal water molecules (III, IV). The substances are moderately soluble in water; highly soluble in polar organic solvents, such as acetone, ethanol, chloroform, methylene chloride; and almost insoluble in carbon tetrachloride and toluene. Under storage in light, the compounds decompose from the surface; in darkness I and II are stable, whereas III and IV can lose part of the crystal water.     

Isolation and Structural Characterization of Di‐ and Tetra‐protonated Forms of the Macrocyclic Hexaamine trans‐6,13‐Dimethyl‐1,4,8‐11‐tetraazacyclodecane‐6,13‐diamine

Cations derived by protonation of the ligand title compound (L¹) have been structurally characterized in their di‐ and tetra‐ protonated forms in the salts [H₂L¹][ClO₄]₂·2H₂O and [H₄L¹][ZnCl₄]₂·4H₂O. In both structures, one half of the formula unit comprises the asymmetric unit of the structure, the macrocycle being centrosymmetric, with the two macrocycles adopting similar conformations. In both salts, a pair of diagonally opposed macrocyclic secondary amine groups are protonated; in the [H₄L¹]⁴⁺ salt, the additional pair of protons are accommodated on the exocyclic pendant amine groups. The dispositions of the pendent amines differ between the two structures, being ‘equatorial’ with respect to the macrocyclic ring in the [H₂L¹]²⁺ salt, and ‘axial’ in the [H₄L¹]⁴⁺ salt. In other structurally characterized compounds containing [H₄L¹]⁴⁺ the equatorial disposition was found in the ferricyanide adduct, while in the tetraperchlorate salt the axial disposition was identified. The differences in disposition of the exocyclic groups are ascribed to the extensive H‐bonding in the lattices.     

Synthesis and Crystal Structure of a Zinc(II) Complex Salt with the Schiff Base of Picolinaldehyde N-oxide and Semicarbazone

1 INTRODUCTION The donor properties of pyridine N-oxide and its substituted derivatives to form metal complexes have been widely investigated[1～3]. The resulting comple- xes were used as drugs[4] and catalysts[5]. So far, there have been a few reports on the synthesis of Schiff base derived from picolinaldehyde N-oxide with se- micarbazone (PNOS Scheme 1) and its metal com- plexes. And crystal structures of the complexes of PNOS with Au(III)[6], Pd(II)[7] and Cu(II)[8] were re- …     

Synthesis and Crystal Structure of 1,4-Bis(2-hydroxymethylphenyl)-1,4-dioxabutane

1 INTRODUCTION Macrocyclic ligands and their metal complexes have received much attention due to their applications in ion transport, ion separation and as models in biomimic researches[1~7]. The synthetic methods of macrocyclic ligands and their metal complexes are mainly divided into three kinds[8]. The first one is synthesizing free ligand, then forming the metal complexes; the second is template synthesis; and the third is synthesizing the end-off or side-off precursor ligand, then c…     

一维链配位聚合物[Mn(acacen){N(CN)2}]n的合成、结构和性质的研究(英)

The manganese(Ⅲ) complex [Mn(acacen){N(CN)₂}]_n [H₂acacen=bis(acetylacetone)ethylenediimine] has been synthesized and the structure has been determined. The complex forms a one-dimensional chain structure via the bidentate bridge ligand μ_1,5-[N(CN)₂]^- linking [Mn(acacen)] moiety. The magnetic property of the compound (75～300 K) shows the existence of an antiferromagnetic exchange interaction among paramagnetic centers along the chain. CCDC: 244940.