Reactions of Vanadium Dioxide Molecules with Acetylene: Infrared Spectra of VO₂(η²‑C₂H₂)_<i>x</i> (<i>x</i> = 1, 2) and OV(OH)CCH in Solid Neon

Reactions of vanadium dioxide molecules with acetylene have been studied by matrix isolation infrared spectroscopy. Reaction intermediates and products are identified on the basis of isotopic substitutions as well as density functional frequency calculations. Ground state vanadium dioxide molecule reacts with acetylene in forming the side-on-bonded VO₂(η²-C₂H₂) and VO₂(η²-C₂H₂)₂ complexes spontaneously on annealing in solid neon. The VO₂(η²-C₂H₂) complex is characterized to have a ²B₂ ground state with <i>C</i>_2<i>v</i> symmetry, whereas the VO₂(η²-C₂H₂)₂ complex has a ²A ground state with <i>C</i>₂ symmetry. The VO₂(η²-C₂H₂) and VO₂(η²-C₂H₂)₂ complexes are photosensitive. The VO₂(η²-C₂H₂) complex rearranges to the OV­(OH)­CCH molecule upon UV–vis light excitation

Infrared Photodissociation Spectroscopic and Theoretical Study of Homoleptic Dinuclear Chromium Carbonyl Cluster Cations with a Linear Bridging Carbonyl Group

Infrared spectra of mass-selected homoleptic dinuclear chromium carbonyl cluster cations Cr₂(CO)_<i>n</i>⁺ with <i>n</i> = 7–9 are measured via infrared photodissociation spectroscopy in the carbonyl stretching frequency region in the gas phase. The structures are established by comparison of the experimental spectra with the simulated spectra derived from density functional calculations. The Cr₂(CO)_<i>n</i>⁺ cluster cations are characterized to have the (OC)₅Cr–C–O–Cr­(CO)_<i>n</i>−6⁺ structures with a linear bridging carbonyl group bonded to one chromium atom through its carbon atom and to the other chromium atom through its oxygen atom. The cluster cations all have a sextet ground state with the positive charge and the unpaired electrons located on the Cr­(CO)_<i>n</i>−6 moiety. The formation of the linear bridging structures without Cr–Cr bonding can be rationalized that chromium forms strong Cr–CO bonds but weak Cr–Cr bonds

Infrared Photodissociation Spectroscopy of Mass Selected Homoleptic Copper Carbonyl Cluster Cations in the Gas Phase

Infrared spectra of mass-selected homoleptic copper carbonyl cluster cations including dinuclear Cu₂(CO)₆⁺ and Cu₂(CO)₇⁺, trinuclear Cu₃(CO)₇⁺, Cu₃(CO)₈⁺, and Cu₃(CO)₉⁺, and tetranuclear Cu₄(CO)₈⁺ are measured via infrared photodissociation spectroscopy in the carbonyl stretching frequency region. The structures are established by comparison of the experimental spectra with simulated spectra derived from density functional calculations. The Cu₂(CO)₆⁺ cation is characterized to have an unbridged <i>D</i>_3<i>d</i> structure with a Cu–Cu half bond. The Cu₂(CO)₇⁺ cation is determined to be a weakly bound complex involving a Cu₂(CO)₆⁺ core ion. The trinuclear Cu₃(CO)₇⁺ and Cu₃(CO)₈⁺ cluster cations are determined to have triangle Cu₃ core structures with <i>C</i>₂ symmetry involving two Cu­(CO)₃ groups and one Cu­(CO)_<i>x</i> group (<i>x</i> = 1 or 2). In contrast, the trinuclear Cu₃(CO)₉⁺ cluster cation is determined to have an open chain-like (OC)₃Cu–Cu­(CO)₃–Cu­(CO)₃ structure. The tetranuclear Cu₄(CO)₈⁺ cluster cation is characterized to have a tetrahedral Cu₄⁺ core structure with all carbonyl groups terminally bonded

Carbonyl Bonding on Oxophilic Metal Centers: Infrared Photodissociation Spectroscopy of Mononuclear and Dinuclear Titanium Carbonyl Cation Complexes

Mononuclear and dinuclear titanium carbonyl cation complexes including Ti­(CO)₆⁺, Ti­(CO)₇⁺, TiO­(CO)₅⁺, Ti₂(CO)₉⁺ and Ti₂O­(CO)₉⁺ are produced via a laser vaporization supersonic cluster source. The ions are mass selected in a tandem time-of-flight mass spectrometer and studied with infrared photodissociation spectroscopy in the CO stretching frequency region. The structures are established by comparison of the experimental spectra with simulated spectra derived from density functional calculations. Only one IR band is observed for the 15-electron Ti­(CO)₆⁺ cation, which is characterized to have an octahedral <i>O</i>_<i>h</i> structure. The Ti­(CO)₇⁺ cation is determined to be a weakly bound complex involving a Ti­(CO)₆⁺ core ion instead of the seventh coordinated ion. The TiO­(CO)₅⁺ cation has a completed coordination sphere with a C_4v structure. The Ti₂(CO)₉⁺ cation is determined to have a doublet <i>C</i>_<i>s</i> structure with two four-electron donor side-on bridging CO groups and one semibridging CO group. The Ti₂O­(CO)₉⁺ cation has a doublet <i>C</i>_<i>s</i> structure involving a planar cyclic Ti₂O­(η²-μ-CO) core with a four electron donor side-on bridging CO. Bonding analysis indicates that the Ti₂(CO)₉⁺ and Ti₂O­(CO)₉⁺ cations each have a Ti–Ti single bond. The results suggest that metal–metal multiple bonding is not favorable, and the oxophilic titanium centers failed to satisfy the 18-electron configuration in these metal carbonyl complexes

Summary statistics of the ESTs generated from the German cockroach through pyrosequencing.

<p>Summary statistics of the ESTs generated from the German cockroach through pyrosequencing.</p

Genes related to important physiological functions.

<p>Genes related to important physiological functions.</p

Phylogeny of the OBPs (A) and CSPs (B) from the German cockroach and their homologs.

<p>The unrooted consensus trees with 1000 bootstrap replicates are generated in MEGA6 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106932#pone.0106932-Tamura1" target="_blank">[39]</a> using the neighbor-joining method. The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. All positions containing gaps and missing data are eliminated. GenBank accession numbers and species names of the sequences used here are shown in the phylogenetic trees. German cockroach OBPs and CSPs (marked by •) are in bolds.</p

Length distribution of clean reads (A) produced by 454 pyrosequencing and the assembled unigenes (B).

<p>Length distribution of clean reads (A) produced by 454 pyrosequencing and the assembled unigenes (B).</p

Genes related to innate immunity.

<p>Genes related to innate immunity.</p

Phylogeny of two gustatory receptor genes from the German cockroach.

<p>Unigenes c5791 (A) and c rep c30027 (B) are highlighted in bolds and triangles (▴).</p