Sodium hydrogen dipicolinate dipicolinic acid trihydrate: Synthesis,structure, and valence bond sums

The synthesis and crystal structure of sodium hydrogen dipicolinate dipicolinic acid trihydrate, NaHdipic · H₂dipic · 3H₂O,I, is reported. There is a hydrogen bonded H₃(dipic)₂ ^– unit in which an Hdipic^– ion functions as a tridentate chelate to the Na⁺ ion while the second H₂dipic functions as a monodentate ligand and bridging unit. The Na⁺ ion is in the center of a pentagonal bipyramid with two water molecules in the axial positions. The equatorial plane is composed of an Hdipic^– ion, a water molecule and an oxygen from the H₂dipic. An analysis of data in the Cambridge Structural Database for Na⁺ compounds using Valence Bond Sums has produced newr ₀ values of 1.743 for Na–O and 1.891 for Na–N.     

Energy spectra for decaying 2D turbulence in a bounded domain

We use results derived in the framework of the replica approach to study the liquid-glass thermodynamic transition. The main results are derived without using replicas and applied to the study of the Lennard-Jones binary mixture introduced by Kob and Andersen. We find that there is a phase transition due to the entropy crisis. We compute both analytically and numerically the value of the phase transition point T(K) and the specific heat in the low temperature phase.     

Structure and spectral properties of 10-(3-dimethylaminopropyl)phenothiazinium chloride and Reinecke salts

The IR and visible spectra of HPromazine⁺ deuteroreineckate^–, DPromazine⁺ reineckate^– and HPromazine⁺ reineckate^–, reineckate^– is Cr(NCS)₄(NH₃) ₂ ^– are reported together with the X-ray crystal structure determination of the latter. The assignment of the IR bands and the visible spectra are discussed in conjunction with the X-ray data. There is extensive hydrogen bonding in crystalline HPromazine⁺ reineckate^– and the influence of the hydrogen bonding on the dimensions of the reineckate^– anion is discussed. The folding of the phenothiazine ring in various derivatives is analyzed.