Heterometallic heterochalcogenmethylarsenide clusters: Synthesis,molecular structures,and thermolysis

Reactions of the arsinechalcogenide complexes [Fe₃(μ₃-X)(μ₃-AsCH₃)(CO)₉] (X = Se (Ia) or Te (Ib)) with (PPh₃)₂Pt(PhC≡CPh) (transmetalation reaction) and Cp₂Cr₂(SCME₃)₂S (Cp = π-C₅H₅) (photochemical reaction) gave the heterometallic (heterochalcogen)(methylarsine) clusters [(PPh₃)₂Pt(μ₃-X)(μ₃-AsCH₃)Fe₂(CO)₆] (II and III, respectively), as well as Fe₃(μ₃-X)(μ₃-AsCH₃)(CO)₈(C₅H₅)₂Cr₂(μ₃-S)(μ₂-S ^t Bu)₂ (IV and V, respectively). The structures of complexes II, IV, and V were determined by X-ray diffraction analysis. Thermolysis of all the complexes yielded no metal carbides or oxides.     

Chalcogen arsenide clusters of iron with a functional carboxyl group: Synthesis, structures, and thermolysis

The carbonyl clusters [Fe₃(??₃-Q)(??₃-AsR)(CO)₉] (Q = Se and Te; R = meta- and para-HOOCC₆H₄) were obtained from the salts K₂[Fe₃(??₃-Q)(CO)₉] and organoarsenic diiodides RAsI₂ prepared by reducing iodination of arsonic acids RAsO(OH)₂ according to a novel method. The structures of the clusters were identified by X-ray diffraction. The crystal packing motifs of the dimers of the cluster molecules and their relationship with the solubility of the clusters are discussed. The sequential steps of the thermolysis (decarbonylation, decarboxylation, and decomposition of the organic fragment) of the clusters were studied. The presence and location of the carboxyl group does not influence the decarbonylation temperature.     

Syntheses and structures of the cobalt, nickel, and zinc complexes with 1,4-diaza-1,3-butadiene ligands

Several cobalt(II), nickel(II), and zinc(II) complexes with a series of ligands of the 1,4-diaza-1,3-butadiene type bearing aryl (2,6-di-iso-propylphenyl, mesityl) and alkyl (tert-butyl, iso-propyl) substituents at the nitrogen atoms are synthesized. The obtained complexes are characterized by X-ray structure analysis, IR spectroscopy, and elemental analysis.     

Iron chalcogenide carbonyl clusters and their heterometallic derivatives

This paper reviews the results of XRD, Mössbauer, and¹H,⁷⁷Se, and¹²⁵Te NMR studies of the structure of iron chalcogenide carbonyl clusters with a Fe₃X (X = Se, Te) framework and a series of their heterometallic derivatives synthesized by successive replacement of mononuclear iron carbonyl fragments by isolobal metallorganic groups containing Mo and W.     

Cyclic aryleneazachalcogens: Synthesis,vibrational spectra,and π-electron structures

It is shown that a convenient general method for the synthesis of benzo-2,1,3-thiadiazole, its Se analog, their 4,5,6,7-tetrafluoro derivatives, and naphtho[1,8-c,d][1.2.6]thiadiazine is the reaction of the corresponding arylenediamines with chalcogen tetrahalides. A complete interpretation of the vibrational spectra of the synthesized compounds was obtained using the experimental shifts of the bands caused by the introduction of the ¹⁵N and ⁷⁷Se isotopes into the compositions of the molecules and calculations of the frequencies and forms of the normal vibrations within the stretching-force field approximation. The peculiarities of the -electron structures of the molecules of these substances were established by means of an analysis of the force constants of the CC, CN, NS, and NSe bonds and quantum-chemical calculations by the MNDO method: 1) The group orbitals of the NXN fragments (X=S, Se) interact effectively with the group orbitals of the carbocycles; 2) the p AO of nitrogen and sulfur make the principal contribution to the MO of different symmetries (a₂ and b₁, respectively), as a consequence of which their overlapping with one another is small, and the chemical bond within the limits of the NSN group is best described in the form of ; resonance; the same is also valid for the NSeN group; 3) on the whole, the MO display a tendency for localization in individual molecular fragments. All of these factors decrease the aromatic character of the molecules.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1124–1133, August, 1990.     

Samarium Polyarsenides Derived from Nanoscale Arsenic

Zintl phases of arsenic and molecular compounds containing Zintl‐type polyarsenide ions are of fundamental interest in basic and applied sciences. Unfortunately, the most obvious and reactive arsenic source for the preparation of defined molecular polyarsenide compounds, yellow arsenic As₄, is very inconvenient to prepare and neither storable in pure form nor easy to handle. Herein, we present the synthesis and reactivity of elemental As⁰ nanoparticles (As⁰_Nano, d=7.2±1.8 nm), which were successfully utilized as a reactive arsenic source in reductive f‐element chemistry. Starting from [Cp*₂Sm] (Cp*=η⁵‐C₅Me₅), the samarium polyarsenide complexes [(Cp*₂Sm)₂(μ‐η²:η²‐As₂)] and [(Cp*₂Sm)₄As₈] were obtained from As⁰_nano, thereby generating the largest molecular polyarsenide of the f‐elements and circumventing the use of As₄ in preparative chemistry.     

An EXAFS study of the molecular structure of heterometallic chalcogenide clusters

Applicability of EXAFS spectroscopy for determination of the molecular structure of heterometallic chalcogenide clusters in the crystalline state and in solution was examined. The spatial structure of the metal core of the FeMoW(μ₃-Se)(CO)₇(η⁵-C₅H₅) cluster was determined using EXAFS data obtained at the K absorption edge for Fe, Mo, and Se and at the L_III-edge for W. The geometric parameters (the bond lengths and bond angles) obtained from EXAFS data are close to those determined by X-ray analysis. The Mo K-edge EXAFS study of the structurally similar FeMo₂Te(CO)₇(η⁵-C₅H₅) cluster both in the crystalline state and ino-xylene solution confirmed that the geometry of the metal core of the cluster is retained in solution. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1395–1398, August, 2000.