New examples of metalloaromatic Al-clusters: (Al4M4)Fe(CO)3 (M = Li, Na and K) and (Al4M4)2Ni: rationalization for possible synthesis

Ab initio calculations reveal that all-metal antiaromatic molecules like Al4M4 (M = Li, Na and K) can be stabilized in half sandwich (Al4M4)Fe(CO)3 and full sandwich (Al4M4)2Ni complexes. The formation of the full sandwich complex [(Al4M4)2Ni] from its organometallic precursor depends on the stability of the organic-inorganic hybrid (C4H4)Ni(Al4Li4).     

M4 @Si28 (M=Al,Ga): metal-encapsulated tetrahedral silicon fullerene

It is known that silicon fullerenes cannot maintain perfect cage structures like carbon fullerenes. Previous density-functional theory calculations have shown that even with encapsulated species, nearly all endohedral silicon fullerenes exhibit highly puckered cage structures in comparison with their carbon counterparts. In this work, we present theoretical evidences that the tetrahedral fullerene cage Si(28) can be fully stabilized by encapsulating a tetrahedral metallic cluster (Al(4) or Ga(4)). To our knowledge, this is the first predicted endohedral silicon fullerene that can retain perfectly the same cage structure (without puckering) as the carbon fullerene counterpart (T(d)-C(28) fullerene). Density-functional theory calculations also suggest that the two endohedral metallosilicon fullerenes T(d)-M(4)@Si(28) (M=Al and Ga) can be chemically stable because both clusters have a large highest occupied molecular orbital-lowest unoccupied molecular orbital energy gap ( approximately 0.9 eV), strong spherical aromaticity (nucleus-independent chemical shift value of -36 and -44), and large binding and embedding energies.     

Ab initio Study of Structure and Stability of M2Al2 (M: Cu,Ag, and Au) Clusters

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.     

ChemInform Abstract: Molecular and Electronic Structures of TiMH+6 (M: B,Al, Ga) Compounds.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: M4C9+ (M: Ti,V): New Gas Phase Clusters.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: The First Oligomeric Anions of Fluoro-Litho Metallates with Octahedra Sandwich Motive: Cs4K((F3M(III)F3)Li(F3M(III)F3)), M(III): Ga,Fe.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Vibrational spectra and analyses of MFe(CO)4 (M = Cd,Hg)

The IR and Raman spectra of the compounds CdFe(CO)₄ and HgFe(CO)₄, are reported and assigned using C_2v, local symmetry around the iron atom; vibrational analyses of the spectra have also been carried out. The spectroscopic data obtained indicate that the compounds are probably polymers with a centre of symmetry and an octahedral configuration about the iron atom in accordance with X-ray structural results.     

Addition of CCl4 to unsaturated compounds catalyzed by M3(CO)12 (M=Fe, Ru, Os)

The addition of CCl₄ to hex-1-ene and to the methyl ester ofN-(trans-cinnamoyl)-l-proline (2) catalyzed by M₃(CO)₁₂ or by the M₃(CO)₁₂+DMF system (M=Fe, Ru, Os) was studied. The use of ruthenium and osmium dodecacarbonyls in combination with DMF increases the yields of adducts CCl₃CH₂CHClC₄H₉ (4) and PhCHClCH(CCl₃)C(O)R′ (3) over those obtained in reactions catalyzed by the same carbonyls without DMF. In addition to adduct3, salts [M(CO₃)Cl₃]⁻[Me₂NH₂]⁺ were isolated from the products of the reaction between CCl₄ and1 in the presence of M₃(CO)₁₂+DMF (M=Ru, Os). These salts do not catalyze this reaction and apparently result from chain termination. Experimental results in favor of a coordination mechanism of the addition of CCl₄ to olefins in the presence of Ru₃(CO)₁₂ and Os₃(CO)₁₂ were obtained. Translated fromIzvestiya Akademii Nauk Seriya Khimicheskaya, No. 6, pp. 1174–1179, June, 1997.     

Design, formation and properties of tetrahedral M(4)L(4) and M(4)L(6) supramolecular clusters

The rigid tris- and bis(catecholamide) ligands H(6)A, H(4)B and H(4)C form tetrahedral clusters of the type M(4)L(4) and M(4)L(6) through self-assembly reactions with tri- and tetravalent metal ions such as Ga(III), Fe(III), Ti(IV) and Sn(IV). General design principles for the synthesis of such clusters are presented with an emphasis on geometric requirements and kinetic and thermodynamic considerations. The solution and solid-state characterization of these complexes is presented, and their dynamic solution behavior is described. The tris-catecholamide H(6)A forms M(4)L(4) tetrahedra with Ga(III), Ti(IV), and Sn(IV); (Et(3)N)(8)[Ti(4)A(4)] crystallizes in R3(-)c (No. 167), with a = 22.6143(5) A, c = 106.038(2) A. The cluster is a racemic mixture of homoconfigurational tetrahedra (all Delta or all Lambda at the metal centers within a given cluster). Though the synthetic procedure for synthesis of the cluster is markedly metal-dependent, extensive electrospray mass spectrometry investigations show that the M(4)A(4) (M = Ga(III), Ti(IV), and Sn(IV)) clusters are remarkably stable once formed. Two approaches are presented for the formation of M(4)L(6) tetrahedral clusters. Of the bis(catecholamide) ligands, H(4)B forms an M(4)L(6) tetrahedron (M = Ga(III)) based on an "edge-on" design, while H(4)C forms an M(4)L(6) tetrahedron (M = Ga(III), Fe(III)) based on a "face-on" strategy. K(5)[Et(4)N](7)[Fe(4)C(6)] crystallizes in I43(-)d (No. 220) with a = 43.706(8) A. This M(4)L(6) tetrahedral cluster is also a racemic mixture of homoconfigurational tetrahedra and has a cavity large enough to encapsulate a molecule of Et(4)N(+). This host-guest interaction is maintained in solution as revealed by NMR investigations of the Ga(III) complex.     

ChemInform Abstract: A Systematic Study of the Crystal Structures of TlMX4 (M: Al,Ga; X: Cl,Br, I).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Crystal Structures of Two Sodium Yttrium Molybdates: NaY(MoO4)2 (I) and Na5Y(MoO4)4 (II).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Electronic Structures of Octahedral Cluster Halides of Transition Metals (M6X8)n+, (M6X12)n+, and their Interstitial Compounds (M6X12Z)

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

ChemInform Abstract: Hexatellurium Rings in Coordination Polymers and Molecular Clusters: Synthesis and Crystal Structures of [M(Te6)]X3 (M: Rh,Ir; X: Cl,Br, I) and [Ru2(Te6)] (TeBr3)4(TeBr2)2.

Black crystals of [Rh(Te₆)]Br₃ (I), [Rh(Te₆)]I₃ (II), [Ir(Te₆)]Cl₃ (III), [Ir(Te₆)]Br₃ (IV), and [Ir(Te₆)]I₃ (V) are prepared from stoichiometric mixtures of Rh or Ir, Te, and TeX₄ (X: Cl, Br, I; evacuated silica tube, 300—350 °C, 7 d).     

Peculiar transformation of a nonaromatic Al(4)Cl(4)(NH(3))(4) into an aromatic Na(2)Al(4)Cl(4)(NH(3))(4)

We analyzed the molecular orbitals for a Al(4)Cl(4)(NH(3))(4) compound, which is a model of the (AlBr x NEt(3))(4) crystal structure recently reported by Schn?ckel and co-workers. We found that even though Al(4)Cl(4)(NH(3))(4) contains a planar square Al(4) cluster it is not an aromatic compound. However, the addition of two sodium atoms to Al(4)Cl(4)(NH(3))(4) yields a new Na(2)Al(4)Cl(4)(NH(3))(4) compound which is a pi-aromatic molecule. We hope that prediction of this new compound will facilitate a synthesis of aluminum aromatic solids.     

Die Pentatelluride M2Te5 (M = Al,Ga, In): Polymorphie,Strukturbeziehungen und Homogenitätsbereiche

The Pentatellurides M₂Te₅ (M = Al, Ga, In): Polymorphism, Structural Relations, and Homogeneity Ranges The hitherto unknown crystal structure of the black solid Al₂Te₅ is solved by Rietveld refinement of X-Ray powder data: a = 1359.29(3) pm, b = 415.27(1) pm, c = 983.92(2) pm, β = 126.97(1)°, space group: C2/m (no. 12), Z = 2. In contrast to Ga₂Te₅ and In₂Te₅Al₂Te₅ is very sensitive to hydrolysis. It can formally be described as Te[AlTe_3/3Te_1/1]₂, containing layers made up of chains of cis-edge-sharing AlTe₄ tetrahedra [AlTe_3/3Te_1/1] and additional Te atoms. In₂Te₅-I and In₂Te₅-II are characterized by layers with a similar topology, Ga₂Te₅ however is different. It has no layer structure, but contains chains of trans-edge-sharing GaTe₄-tetrahedra and additional Te-atoms according to the formulation Te[GaTe_4/2]₂. It can be regarded as a variant of the TlSe type structure. From heterogeneous samples with the nominal composition In_0.5Ga_1.5Te₅ single crystals of a new stacking variant (In₂Te₅-III) of the In₂Te₅ structure type can be isolated. The composition of the crystals, determined by single crystal structure analysis, is In_0.77Ga_1.23Te₅, with a = 1613.2(3) pm, b = 424.6(1) pm, c = 1330.5(2) pm, β = 97.39(1)°, space group C2/c (Nr. 15), Z = 4. This structure type is not yet known for unsubstituted In₂Te₅. The range of homogeneity for Ga₂Te₅ with respect to the substitution of Gallium by Indium is given by Ga_2-xIn_xTe₅ (x < 0.4). Within the limits of experimental error however a substitution of Te in Ga₂Te₅ by Se cannot be detected.