Monohalogenated ferrocenes C5H5FeC5H4X (X = Cl,Br and I) and a second polymorph of C5H5FeC5H4I

The structures of the three title monosubstituted ferrocenes, namely 1‐chloroferrocene, [Fe(C₅H₅)(C₅H₄Cl)], (I), 1‐bromoferrocene, [Fe(C₅H₅)(C₅H₄Br)], (II), and 1‐iodoferrocene, [Fe(C₅H₅)(C₅H₄I)], (III), were determined at 100 K. The chloro‐ and bromoferrocenes are isomorphous crystals. The new triclinic polymorph [space group P, Z = 4, T = 100 K, V = 943.8 (4) ų] of iodoferrocene, (III), and the previously reported monoclinic polymorph of (III) [Laus, Wurst & Schottenberger (2005). Z. Kristallogr. New Cryst. Struct. 220 , 229–230; space group Pc, Z = 4, T = 100 K, V = 924.9 ų] were obtained by crystallization from ethanolic solutions at 253 and 303 K, respectively. All four phases contain two independent molecules in the unit cell. The relative orientations of the cyclopentadienyl (Cp) rings are eclipsed and staggered in the independent molecules of (I) and (II), while (III) demonstrates only an eclipsed conformation. The triclinic and monoclinic polymorphs of (III) contain nonbonded intermolecular I...I contacts, causing different packing modes. In the triclinic form of (III), the molecules are arranged in zigzag tetramers, while in the monoclinic form the molecules are arranged in zigzag chains along the a axis. Crystallographic data for (III), along with the computed lattice energies of the two polymorphs, suggest that the monoclinic form is more stable.     

ChemInform Abstract: Ab initio Studies on Disubstituted closo-Icosahedral Heteroboranes,X2B10H10 (X: CH,SiH, N,P, and Sb).

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ChemInform Abstract: Chemistry in Superacids. Part 40. Protonated Borane—Lewis Base Complexes BH4X+ (X: NH3, PH3, H2O,H2S,CO).

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Substitution and protonation effects on spin-spin coupling constants in prototypical aromatic rings: C6H6, C5H5N and C5H5P

Ab initio equation-of-motion coupled cluster calculations have been carried out to evaluate one-, two-, and three-bond 13C-13C, 15N-13C, 31P-13C coupling constants in benzene, pyridine, pyridinium, phosphinine, and phosphininium. The introduction of N or P heteroatoms into the aromatic ring not only changes the magnitudes of the corresponding X-C coupling constants (J, for X = C, N, or P) but also the signs and magnitudes of corresponding reduced coupling constants (K). Protonation of the heteroatoms also produces dramatic changes in coupling constants and, by removing the lone pair of electrons from the sigma-electron framework, leads to the same signs for corresponding reduced coupling constants for benzene, pyridinium, and phosphininium. C-C coupling constants are rather insensitive to the presence of the heteroatoms and protonation. All terms that contribute to the total coupling constant (except for the diamagnetic spin-orbit (DSO) term) must be computed if good agreement with experimental data is to be obtained.     

The crystal structure of the Cu+ ion conductor, (C5H5NH)2Cu5Br7

(C₅H₅NH)₂Cu₅Br₇, in which (C₅H₅NH)⁺ is the pyridinium ion, belongs to space group P2₁2₁2₁ with Z = 4 and a = 13.09 ± 0.03 Å, b = 14.04 ± 0.03 Å, c = 11.78 ± 0.02Å. The 20 Cu⁺ ions are distributed non-uniformly over 52 tetrahedral sites. The bromide tetrahedra share faces in such a manner that undulating channels are formed in the [100] and [010] directions, and right- and left-handed helical channels are formed in the c-direction. The channels are interconnected, thereby forming a three-dimensional solid electrolyte. A detailed examination of the conduction pathways and of Cu⁺ ion site occupancies leads to the predictions that σ₂ (|b) should be somewhat greater than σ₁ (|a) but σ₃ (|c) should be substantially less than σ₁. (σ_i is the specific conductivity in the ith direction.) The ratio of available sites to current carriers and the percentage of unit cell volume attributable to the conduction pathways are both rather low and the average conductivity is rather high relative to AgI-based solid electrolytes.     

Electron attachment to SF5X compounds: SF5C6H5, SF5C2H3, S2F10, and SF5Br, 300-550 K

Rate constants and ion product channels have been measured for electron attachment to four SF5 compounds, SF5C6H5, SF5C2H3, S2F10, and SF5Br, and these data are compared to earlier results for SF6, SF5Cl, and SF5CF3. The present rate constants range over a factor of 600 in magnitude. Rate constants measured in this work at 300 K are 9.9+/-3.0x10(-8) (SF5C6H5), 7.3+/-1.8x10(-9) (SF5C2H3), 6.5+/-2.5x10(-10) (S2F10), and 3.8+/-2.0x10(-10) (SF5Br), all in cm3 s-1 units. SF5- was the sole ionic product observed for 300-550 K, though in the case of S2F10 it cannot be ascertained whether the minor SF4- and SF6- products observed in the mass spectra are due to attachment to S2F10 or to impurities. G3(MP2) electronic structure calculations (G2 for SF5Br) have been carried out for the neutrals and anions of these species, primarily to determine electron affinities and the energetics of possible attachment reaction channels. Electron affinities were calculated to be 0.88 (SF5C6H5), 0.70 (SF5C2H3), 2.95 (S2F10), and 2.73 eV (SF5Br). An anticorrelation is found for the Arrhenius A-factor with exothermicity for SF5- production for the seven molecules listed above. The Arrhenius activation energy was found to be anticorrelated with the bond strength of the parent ion.     

ChemInform Abstract: Theoretical Studies of Inorganic Compounds. Part 19. Quantum Chemical Investigations of the Phosphane Complexes X3B‐PY3 and X3Al‐PY3 (X: H,F, Cl; Y: F,Cl, Me,CN).

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ChemInform Abstract: Theoretical Study of the Persilacyclopentadienyl Sandwich Compound, ( Si5H5)2Fe.

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Systematic DFT Study of Gas Phase and Solvated Uranyl and Neptunyl Complexes [AnO2X4]n (An: U,Np; X: F,Cl, OH,n = ‐2; X: H2O,n = +2).

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ChemInform Abstract: Pseudopotential Investigations on the Molecules Cu2Si2, Cu2Sn2, Cu4Si4, and Cu4Sn4

show the equilibrium structures to be the butterfly arrangement for the Cu₂X₂ clusters and the heterocubane arrangement for the Cu₄X₄ clusters.     

ChemInform Abstract: Magnetic and X‐Ray Absorption Studies on the RE5X2Sb6 (RE: Eu,Yb; X: Al,Ga, In) Compounds.

The title compounds (obtained by a high frequency induction heating method) are characterized by magnetic measurements, XANES, and XRD.     

ChemInform Abstract: Electronic Structure,Elastic Anisotropy,Thermal Conductivity and Optical Properties of Calcium Apatite Ca5(PO4)3X (X: F,Cl or Br).

The structural properties, phase stability, electronic structure, elastic properties, and optical properties of Ca₅(PO₃)₄F (FA), Ca₅(PO₃)₄Cl (ClA) and Ca₅(PO₃)₄Br (BrA) are studied by DFT calculations with the generalized gradient approximation.