Crystal structure of complexes of bivalent Co,Ni, and Cd with anions of benzoic and 2-(acetylamino)-5-nitrobenzoic acids

The structure of three complexes of bivalent metals (cobalt, nickel, and cadmium) with anions of benzoic (HL ¹) and 2-(acetylamino)-5-nitrobenzoic (HL ²) acids, namely, [Co₂¹ (H₂O)₂(μ-C₄H₄N₂)] _n (I), [NiL²(H₂O)₅]L² · 2H₂O (II), and [Cd(μ-L ²)₂(H₂O)₂] _n · 2nH₂O (III), is determined. In chainlike structure I, cobalt atoms are connected by bridging pyrazine molecules; structure II contains isolated complexes. In structure III, centrosymmetric (CdOCO)₂ cycles and polymeric ribbons are formed due to the coordination of the carboxylate group of the L ² ligand to two cadmium atoms.     

Synthesis, properties, and crystal structure of barium 1-oxyethylidenediphosphonatohydroxogermanate(IV) polyhydrate Ba3[Ge(μ-OH)(μ-Oedph)]6 · 25H2O

The barium salt of 1-oxyethylidenediphosphonatohydroxogermanium acid Ba₃[Ge(μ-OH)(μ-Oedph)]₆ · 25H₂O (I) (H₄Oedph is 1-oxyethylidenediphosphonic acid) was synthesized and studied by X-ray diffraction. The complex was characterized by elemental analysis, thermogravimetry, and IR spectroscopy. The hexanuclear cyclic complex anions [Ge(μ-OH)(μ-Oedph)] ₆ ^6-t- ] cations, and water molecules of crystallization are the structural units of the crystal of I.     

Coordination compounds of some d metals with anthrapyridinedione derivatives: Crystal structure of 2-phenyl-4-(piperidyl-1)-anthra[1,2-b]pyridine-7,12-dionium hexabromodicuprate(II) (HL1)2[Cu2Br6]

Complexes of copper(II), nickel(II), and cobalt(II) chlorides and bromides with 2-phenyl-4-(piperidyl-1)-anthra[1,2-b]pyridine-7,12-dione (L¹) and 2-[phenyl-4-(octylamino)-anthra[1,2-b]pyridine-7,12-dione (L²) were synthesized from neutral and acidic media. The molecular and crystal structure of 2-phenyl-4-(piperidyl-1)-anthra[1,2-b]pyridine-7,12-dionium hexabromodicuprate(II) (HL¹)₂[Cu₂Br₆] was determined by X-ray diffraction analysis. The spectral characteristics of L¹ and L² and their complexes are presented. Formation of their complexes in solutions was studied.     

Complex compounds of a series of <Emphasis Type="Italic">d</Emphasis> metals with rubazinic acid (HRub). Crystal and molecular structure of [Co(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>](NO<Subscript>3</Subscript>)<Subscript>2</Subscript> · 2HRub

Seven complexes of d elements with rubazinic acid, (4Z)-4-[(5-hydroxy-1,3-dimethyl-1H-pyrazol-4-yl)imino]-2,5-dimethyl-2,4-dihydro-3H-pyrazol-3-one (HRub), were synthesized and studied by IR and UV/Vis spectroscopy and potentiometry. The composition of the complexes in solution was determined by spectrophotometry and their stability constants were calculated. The crystal and molecular structures of [Co(H₂O)₆](NO₃)₂ · 2HRub were determined by X-ray diffraction.     

Complex compounds of some p, d, and f metals with 2,4,6-tris(N,N-dimethylaminomethyl)phenol (HL): Crystal and molecular structure of H4L(NO3)3 · H2O and H4LCl3 · 3H2O

Eight aluminum, cobalt(II), copper(II), cadmium, samarium(III), and europium(III) complexes with 2,4,6-tris(N,N-dimethylaminomethyl)phenol (HL) were isolated in the crystalline state and studied by physicochemical methods (IR and UV-Vis spectroscopy, potentiometry). The complexation processes of singly, doubly, and triply charged metal ions with HL were studied by spectrophotometry and potentiometry, the composition of complexes was determined, and the stability constants were calculated. The crystal and molecular structures of 2,4,6-tris(N,N-dimethylaminomethyl)phenol trichloride and trinitrate H₄L(NO₃)₃ · H₂O and H₄LCl₃ · 3H₂O were studied by X-ray diffraction.     

Ammonium and potassium citratogermanates(IV): Synthesis, chemical compositions, and structures. The crystal structures of (NH4)[Ge(OH)(H2Cit)2] · H2O and K4[Ge(HCit)2(H2Cit)] · 3H2O

Methods for the synthesis of ammonium citratogermanate (NH₄)[Ge(OH)(H₂Cit)₂] · H₂O (I) and potassium citratogermanate (K₄[Ge(HCit)₂(H₂Cit)] · 3H₂O (II), where H₄Cit is citric acid) in aqueous MeCN were developed. The individuality, chemical composition, and thermal stability of complexes I and II were proved by elemental analysis, thermogravimetry, and IR spectroscopy. According to X-ray diffraction data, the coordination numbers of the Ge atoms are 5 and 6 and their coordination polyhedra are a square pyramid and an octahedron in complexes I and II, respectively. In both complexes, the Ge atom coordinates the deprotonated OH group and the α-carboxyl group of the ligands H _n Cit^4?n to form five-membered chelate rings. Hydrogen bonds in I as well as potassium cations in II serve to unite these complexes into frameworks.     

Magnetostructural correlation for the Gd complexes with bridging oxygen

The dependence between the energy of magnetic exchange interaction J _Gd-Gd′ and the distance between gadolinium atoms in the binuclear structure D _Gd...Gd′ was constructed on the basis of our and literature experimental data for 34 gadolinium complexes with the [Gd₂O₂] core. The character of the established dependence is similar to the Bethe-Slater curve. The obtained correlation indicates the possibility to predict the character of interaction in the Gd complexes built of binuclear fragments with the [Gd₂O₂] core depending on the single parameter, namely, distance D _Gd...Gd′. The validity of this correlation was tested using as examples four binuclear gadolinium complexes obtained by the authors.     

New binuclear ferrocenecarboxylates of rare-earth metals as precursors for ferrites: Syntheses,structures, and solid-phase thermolysis

New ferrocenecarboxylates of rare-earth metals, [Ln₂(μ-O,η²-OOCFc)₂(μ₂-O,O′-OOCFc)₂(η²-NO₃)₂(DMSO)₄] (Ln = Gd (I), Tb (II), and Y (III)) and [Gd₂(μ-O,η²-OOCFc)₂(η²-OOCFc)₄(DMSO)₂(H₂O)₂] · 2DMSO · 2CH₂Cl₂ (IV), are synthesized and characterized by X-ray diffraction analysis. Unlike all earlier known ferrocenecarboxylates of rare-earth metals, in isostructural compounds I–III the Ln atoms are linked by four bridging carboxyl residues, two of which are chelate-bridging (the coordination number of Ln is 9). Binuclear structure IV is formed by two chelate-bridging carboxylate ligands (the coordination number of Gd is 9). Weak antiferromagnetic and weak ferromagnetic interactions between the Gd atoms are observed in complexes I and IV, respectively. The thermal decomposition of the synthesized compounds is studied by differential scanning calorimetry and thermogravimetry. According to the X-ray diffraction data, the final thermolysis products of the complexes in air are garnets Ln₃Fe₅O₁₂.