The C[double bond, length as m-dash]O/C[triple bond, length as m-dash]N stretching vibration arising from a carbonyl/nitrile functional group in various molecular systems has been frequently used to assess, for example, local hydrogen-bonding interactions, among other applications. However, in practice it is not always easy to ascertain whether the carbonyl or nitrile group in question is engag...

B y now you should be familiar with position isomers wherein compounds of the same molecular formula differ because substituents, chain branches, and so on, are not at the same positions in the molecules. 1-Chloropropane and 2-chloropropane are straightforward examples of position isomers. A much more subtle form of isomerism is present when two dijfjrerent compounds have the same molecular for...

The nitridorhenium(V) complexes ReNCl(2)(PCy3)(2) (1), ReNBr(2)(PCy3)(2) (2), ReNCl(2)(PPh3)(2) (3), and ReNBr(2)(PPh3)(2) (4) produce structured emission spectra upon excitation at low temperature. The origin, E(00), occurs at 15 775, 16 375, 15 875, and 16 300 cm(-1), respectively. The vibronic peaks are regularly spaced with an average energy separation corresponding to the Re triple bond N ...

Triple bonding is conventionally considered to be the limit for multiply bonded main group elements, despite higher metal-metal bond orders being frequently observed for transition metals and lanthanides/actinides. Here, using high-level theoretical methods, we show that C(2) and its isoelectronic molecules CN(+), BN and CB(-) (each having eight valence electrons) are bound by a quadruple bond....

The title complex, [Au(2)Cl(2)(C(26)H(21)NP(2))], has an intra-molecular Au⋯Au inter-action of 3.1669 (4) Å, but no inter-molecular Au⋯Au inter-actions in the solid state. The Cl-Au-P bond angle of 176.84 (7)° is slightly distorted from linearity. The P-C bond length to the phenyl group is shorter [1.810 (7) Å] than the P-C bond length [1.876 (7) Å] to the bridging carbon, indicative of the fle...

The synthesis, crystal structure, and characterization of a silicon–silicon triply bonded species, disilyne with two bis[bis(trimethylsilyl)methyl]isopropylsilyl substituents, are described. The nature of the sp-hybridized silicon atoms is discussed from the viewpoint of spectroscopic results and theoretical calculations. The reactivity of the disilyne with alkali metals, tBuLi, and π-bonded co...

Breakdown of triple-helical interstitial collagens is essential in embryonic development, organ morphogenesis and tissue remodelling and repair. Aberrant collagenolysis may result in diseases such as arthritis, cancer, atherosclerosis, aneurysm and fibrosis. In vertebrates, it is initiated by collagenases belonging to the matrix metalloproteinase (MMP) family. The three-dimensional structure of...

We present converged first-principles calculations for the atomic and electronic structure of diamond ~111! surfaces based on density-functional theory in the local-density approximation. Singleand triple-danglingbond surfaces with 131, 231, and (A33A3)R30° translational symmetry are studied by means of totalenergy minimizations. The ground-state geometries and electronic band structures are co...

CURRENT SCIENCE, VOL. 104, NO. 12, 25 JUNE 2013 1601 The new international standards are expected to help genebanks worldwide to conserve crop diversity in a more efficient and cost-effective manner. They provide a basis for establishing the norms and standards essential for the smooth operation of a genebank. They can be used by genebank curators as a source of guidance for developing standard...

We theoretically introduce a mesoscopic pendulum from a triple dot. The pendulum is fastened through a singly occupied dot (spin qubit). Two other strongly capacitively coupled islands form a double-dot charge qubit with one electron in excess oscillating between the two low-energy charge states (1,0) and (0,1). The triple dot is placed between two superconducting leads. Under realistic conditi...