A series of [(PNp 3 )Pd(Ar)Br] 2 complexes (PNp 3 = trineopentylphosphine, and 2, were synthesized and structurally characterized by X-ray crystallography and density functional theory optimized structures. The trineopentylphosphine ligand is able to accommodate coordination of other sterically demanding ligands through changes in its conformation. These conformational changes can be seen in changes in percent buried volume of the PNp 3 ligand. The binding equilibria of the [(PNp 3 )Pd(Ar)Br] 2 complexes with pyridine derivatives were determined experimentally and analyzed computationally. The binding equilibria are sensitive to the steric demand of the pyridine ligand and less sensitive to the steric demand of the aryl ligand on palladium. In contrast to previous studies, the binding equilibria do not correlate with pyridine basicity. The binding equilibria results are relevant to fundamental ligand coordination steps in cross-coupling reactions, such as Buchwald−Hartwig aminations.

The structural and energetic reactivities of various carbenes are evaluated against a standard electrophile (proton) and a standard nucleophile (fluoride). The proton and fluoride affinities of the carbenes studied provide an increased understanding of reactivity modes and mechanisms. General classification of carbenic reactivity as a singlet nucleophilic carbene or a singlet electrophilic carbene is facilitated by this present study, and a need for further classification means along the border between electrophilic and nucleophilic reactivity is considered. The results are based on electronic structure calculations at the composite correlated molecular orbital theory G3MP2 level.

A range of carbene structures and their adducts with one another and with a selection of small-molecule electrophiles and nucleophiles were examined at the composite correlated molecular orbital theory G3MP2 level to explore ground-state "carbenic" structures, their stabilities, and reactivities. Differences between carbene general classification as a singlet electrophilic carbene or singlet nucleophilic carbene and their given reactivity are discussed. A key quantity is the carbon−carbon bond dissociation energy for carbene dimers or the carbene-adduct dissociation energy for other species. The carbene dimer bond dissociation energies span a wide range from 10 to 170 kcal/mol. The hydrogenation energies and singlet−triplet splitting were found to correlate best with the carbene's self-dimerization energy, whereas other descriptors do not. The proton and fluoride affinities of the carbenes alone prove inadequate for classifying reactivity among classes of carbenes. The self-dimerization bond dissociation energy, hydrogenation energy, and singlet−triplet splitting of various carbenes, despite sometimes large differences in proton affinity and other indicators of reactivity, provide usable metrics to correlate substantial amounts of thermodynamic and kinetic (reactivity) information regarding these structures.

The arsenic(III) and antimony(III) cyanides M(CN)3 (M=As, Sb) have been prepared in quantitative yields from the corresponding trifluorides through fluoride-cyanide exchange with Me3 SiCN in acetonitrile. When the reaction was carried out in the presence of one equivalent of 2,2'-bipyridine, the adducts [M(CN)3 ⋅(2,2'-bipy)] were obtained. The crystal structures of As(CN)3 , [As(CN)3 ⋅(2,2'-bipy)] and [Sb(CN)3 ⋅(2,2'-bipy)] were determined and are surprisingly different. As(CN)3 possesses a polymeric three-dimensional structure, [As(CN)3 ⋅(2,2'-bipy)] exhibits a two-dimensional sheet structure, and [Sb(CN)3 ⋅(2,2'-bipy)] has a chain structure, and none of the structures resembles those found for the corresponding arsenic and antimony triazides.

What was the inspiration for this cover design?When we received the invitation to submit ac over art, we immediately thought about the web comic "Cyanide &H appiness," written and illustrated by Rob Denbleyker,K ris Wilson, Dave McElfatrick, and Matt Melvin, and published on explosm.net. We are big fans of the often dark and surrealistic comics and wanted to incorporate it into the cover art. Luckily,t he people from C&H were okay with us using some of their characters. The inspiration behind the cyanide work in general is actually going back several years. My group was and still is heavily involved in the synthesis of metal polyazides. Afew years ago, we published the synthesis of binary Group 13 azides in Angewandte Chemie. Azide and cyanide are both pseudohalides and we were wondering if the reaction chemistry of the Group 13 azides can be directly applied to the cyanides. While we were surprised that there is adistinct difference, we were also happy because this gave us an excuse to further look into this chemistry.What other topics are you working on at the moment?Besides our research on metal cyanides, we are active in the following areas:h igh energy density materials (HDEM), environmentally friendly,g reen energetic materials (GEMs), polynitrogen and high nitrogen compounds, chemistry at the limits of oxidation and coordination, the chemistry of superacidic systems, fluorine chemistry,a sw ell as the synthesis and characterization of novel carbocation and fluorocarbon compounds.Is your current researchm ainly curiosity driven (fundamental) or rather applied?Our work features ah ealthy mix of fundamental and applied research. Some topics such as the chemistry of superacidic systems or at the limits of oxidation and coordination are currently driven by curiosity,w hereas other topics such as the research on energetic materials are strongly applied.How did each team member/collaborator contribute to the work? Invited for the cover of this issuei st he group of Ralf Haiges at the University of Southern California.T he image depicts characters from the popular web comic "Cyanide &H appiness" alongside some of the cyanide complexes synthesized. Read the full textoft he article at