Infrared Spectra of Mass-Selected Br⁻−(NH₃)_n and I⁻−NH₃ Clusters

Abstract

Table 1. Data for Br -, NH 3 and Br --NH 3 at MP2/aug-cc-pVDZ and MP2/aug-cc-pVTZ levels. Listed are optimized internal coordinates (r in Å, θ in degrees), harmonic vibrational frequencies (ω in cm -1 , intensities in km/mol in brackets), zpe (in kcal/mol), electronic energies (E in au), dissociation energy (D 0 in cm -1 ), and enthalpy change for association reaction at 298K (

Adding Remnant Magnetization and Anisotropic Exchange to Propeller‐like Single‐Molecule Magnets through Chemical Design

“…Steric effects also play a role, for it appears that the simultaneous encapsulation of triflate and a halide is unfavorable, whereas the smaller neutral ligand and halide association presents a complementary host–guest arrangement. In the case of NH 3 ‐containing 2 , the stabilization of the iodide adduct might also derive from favorable hydrogen‐bonding interactions between the two guests 20. As CH⋅⋅⋅I interactions involving NMe 3 in 3 would be weaker than the NH⋅⋅⋅I hydrogen bonds in 2 ,21 the stronger iodide association constant in this case might be attributed to a more complementary guest packing arrangement within the host cavity as a result of the larger NMe 3 ligand.…”

Quantifying Intrinsic Ion-Driven Conformational Changes in Diphenylacetylene Supramolecular Switches with Cryogenic Ion Vibrational Spectroscopy

“…Instead, only one peak appears in the neutral H-bonded NH region whereas a congested series of features, overlapping with the CH region, appears in the 1 -Cl – spectrum and extends over the range 2800–3300 cm –1 . Note that the anionic H-bond to an NH group is known to be quite strong, as evidenced by red-shifts in the NH stretch of hundreds of cm –1 in a manner highly correlated with the proton affinities of the anions. − The strong, red-shifted bands in the 1 -Cl – spectrum near 2800 cm –1 are therefore consistent with ionic H-bonded NH activity, but the complexity of the band structure relative to that of the cationic species indicates that either multiple conformers are in play or anharmonic effects significantly perturb the spectrum of a single conformer. We therefore turn to empirical evolution of the band patterns with chemical and charged adduct variation as a means to validate theoretical interpretation of the spectra in the context of detailed structures.…”

Infrared Multiphoton Dissociation Spectroscopy with Free‐Electron Lasers: On the Road from Small Molecules to Biomolecules

“…However, this complex is not linear, which would be desirable for a systematic study. The ammonium groups interact not only with the halogen anion but also with each other . Demireva et al.…”

“…The ammonium groups interact not only with the halogen anion but also with each other. [21] Demireva et al circumvented this problemb ys tudying complexes of halides with a,w-diaminoalkanes. [22] They used deuterated amines to observe the hydrogen bonding using FEL radiation ( Figure 4).…”