Strained <i>ansa</i> Half-Sandwich Complexes of Ruthenium and Osmium and a Non-Iron Metallopolymer by Ring-Opening Polymerization

Herein we report the first non-iron polymer obtained from an <i>ansa</i> half-sandwich complex. This polymeric organometallic material was obtained from a new disilanediyl-bridged ruthenium complex upon thermally induced ring-opening polymerization (ROP). Additionally, a corresponding distannanediyl-bridged osmium species is reported, the first example of an <i>ansa</i> half-sandwich complex of this element

Exclusive p encapsulation of light alkali metal cations by a neutral molecule

Cation-p interactions are one of the most important classes of non-covalent bonding, and are seen throughout biology, chemistry and materials science. However, in almost every documented case, these interactions play only a supporting role to much stronger covalent or dative bonds, making examples of exclusive cation-p bonding exceedingly rare. In this work, a neutral diboryne molecule is found to encapsulate the light alkali metal cations Li+ and Na+ in the absence of a net charge, covalent bonds, or lone-pair donor groups. The resulting encapsulation complexes are to our knowledge the first structurally authenticated species in which a neutral molecule binds the light alkali metals exclusively through cation-p interactions

Experimental Assessment of the Strengths of B–B Triple Bonds

Diborynes, molecules containing homo­atomic boron–boron triple bonds, have been investigated by Raman spectroscopy in order to determine the stretching frequencies of their central BB units as an experimental measure of homoatomic bond strengths. The observed frequencies between 1600 and 1750 cm^–1 were assigned on the basis of DFT modeling and the characteristic pattern produced by the isotopic distribution of boron. This frequency completes the series of known stretches of homoatomic triple bonds, fitting into the trend established by the long-known stretching frequencies of CC and NN triple bonds in alkynes and dinitrogen, respectively. A quantitative analysis was carried out using the concept of relaxed force constants. The results support the classification of the diboryne as a true triple bond and speak to the similarities of molecules constructed from first-row elements of the p block. Also reported are the relaxed force constants of a recently reported diborabutatriene, which again fit into the trend established by the vibrational spectroscopy of organic cumulenes. As part of these studies, a new diboryne with decreased steric bulk was synthesized, and a computational study of the rotation of the stabilizing ligands indicated alkyne-like electronic isolation of the central B₂ unit