UV-Vis measurements showed that the interaction of pseudohalide anions, A(-) (A(-) = N3(-), NCO(-), NCS(-)), with electrophilic bromocarbons, R-Br (R-Br = CBr4, CBr3NO2, CBr3CONH2, CBr3H, CBr3F, CBr3CN or C3Br2F6), in solution results in formation of [R-Br, A(-)] complexes. These associates are characterized by intense absorption bands in the 200-350 nm range showing distinct Mulliken correlation with the frontier (HOMO-LUMO) orbitals' separations of the interacting anion and the R-Br electrophile. X-ray crystallographic studies established the principal structural features of the halogen-bonded associates between bromocarbons and polydentate pseudohalide anions. Specifically, in the (Pr4N)NCO·CBr4, (Pr4N)N3·CBr4 and (Pr4N)NCO·CBr3NO2 co-crystals, bromine substituents of the electrophiles are halogen-bonded with the (C≡N or N=N) π-bonds of the cyanate or azide anions. Co-crystals of CBr4 with (Pr4N)NCS show two modes (C-Br···S-C and C-Br···N≡C) of halogen bonding, while tribromoacetamide molecules form C-Br···S-C halogen bonds and N-H···N≡C hydrogen bonds with thiocyanate anions. Structures and energetics of the halogen-bonded complexes resulted from the M06-2X/6-311+G(dp) computations of various R-Br-A(-) pairs were consistent with the experimental data. These computations revealed that the variations of the intramolecular (C-Br) and intermolecular (Br···A(-)) bond lengths are correlated with the A(-) → R-Br charge transfer determined from Natural Bond Orbital analysis. Also, the scrutiny of the structural data indicated that the locations of the intermolecular contacts in these associates are determined primarily by the frontier orbital shapes of the halogen-bonded species. Thus, spectral and structural data point out a significant role of molecular-orbital (charge-transfer) interactions in formation of halogen bonded complexes involving pseudohalides and bromocarbons.

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Diana Preston's The Dark Defile describes the disastrous occupation of Afghanistan by Britain from 1839 to 1842. This is a well-known story-depicted in grand nineteenth-century canvases (Remnants of an Army), 1960s comedies (Flashman), and a flurry of books with Victorian titles, published or republished to coincide with our current Afghan mess: Signal Catastrophe, Crimson Snow, The Last Man, Retreat and Retribution, Butcher and Bolt. Most of the books remind us that the British ''Army of the Indus'' swaggered into Kabul from India in 1839; that the general's personal baggage had been loaded on 260 camels; that behind the lancers in their scarlet cloaks and plumed shakos trotted a pack of hounds, which had been led through the arid horrors of the Bolan Pass in order to hunt foxes in the Hindu Kush; and that the Afghans were soon watching ice-skating and giving advice to British women on their geraniums. The British had invaded to replace the Afghan king, because they felt he was becoming too close to the Russians, and that Afghanistan could have been used by Russia to threaten British India. By November 1841, Sir Alexander Burnes, the British political official responsible for Kabul, congratulated his superior, Sir William Hay Macnaghten, on the perfect tranquility of the country. A day later, Burnes was hacked down in the flames of his burning mansion; a week later, the British garrison was under siege; on December 23 Macnaghten's mutilated corpse was hung from a butcher's hook in the bazaar; and on January 6 the British army began its retreat.