Haldane compounds

Stanley Miller at the University of Chicago more than 50 years ago. This experiment (in fact, of course, many were carried out prior to the successful one) is probably as well known as the Wohler synthesis of urea Miller s doctoral supervisor, Harold Urey (winner of the Nobel Prize in 1934), had suggested to Miller that he simulate a reducing primeval Earth atmosphere (as required by the Oparin-Haldane hypothesis) to electrical discharges and see what happens . Urey apparently expected that such an experiment would lead to a huge variety of organic compounds. 

The lethal effects of carbon monoxide on hemoglobin had been analyzed by Claude Bernard and shown to be due to the formation of an iron-carbonyl compound. In 1891 Mond and Langer showed that iron pentacarbonyl could be dissociated by light, and in 1897 J.S. Haldane and J.L. Smith found light would decompose the carbonyl compound of hemoglobin. Other metal carbonyls are not photodecomposed. 

Aminoacyl adenylates have long been known to be high energy compounds, but their free energies of hydrolysis had not been accurately measured. This was accomplished for tyrosyl adenylate using the Haldane approach (Chapter 3, section H) and mutants of the tyrosyl-tRNA synthetase. The equilibrium constant for the formation of tyrosyl adenylate in solution (Absolution) = [Tyr-AMP] [PPi]/ [Tyr] [ATP]) is related to the rate and equilibrium constants for the enzymatic reaction illustrated in Figure 15.21 by equation 15.8. 

This kinetic scheme, of fundamental importance to biochemistry, was first analyzed correctly by Briggs and Haldane. It is often referred to in physicochemical circles as Langmuir-Hinschelwood kinetics and chemical engineers encounter it as Hougen-Watson. In spite of the injustice it does to Briggs and Haldane, it seems best to leave it as Michaelis-Menten. Certainly, BrH3LaM2W is an impossible compound. 

K, Inhibition concentration of a self-inhibitory compound (Haldane kinetics) [ML-3] n Porosity of aquifer material [-]... 

Novel Theoretical Prediction Method of the Haldane Gap among the Azido-Bridged Compounds by DV-Xa Molecular Orbital Calculation Tomohiko Ishii, Yukikazu Fuke, Naoko Aizawa and Masahiro Yamashita ... 

Table 4.1 Intra-chain exchange energy, J, and the Haldane gap, g, of several Haldane gap compounds with particular in-plane and bridging ligands and counteranions...

The crystallographic data of NINAZ, NDMAZ, and NDMAP we have obtained are completely consistent with those reported previously [2]. The cluster model of each compound we have used for the DV-Xa calculation is extracted from the X-ray structural data of the single crystal. Cluster models of the same formula N3-Ni(AA)2-N3-Ni(AA)2-N3 are used in the DV-Xa calculation in order to compare both the electronic structure and the Haldane gap directly. 

In the N3 bridged compounds, there is a stronger electron-electron interaction through the N/ bridging molecule between two adjacent Ni spins, than between the NO2 bridged compounds. A cluster model constructed on the basis of the accurate structure determined by X-ray diffraction is used in the DV-Xa calculation for NINAZ, NDMAZ, and NDMAP. These are typical Haldane gap materials, which include the N3-bridging ligand. 

Figure 4.5 Schematic expression of the singlet (left) and the triplet (right) spin states between two adjacent Ni2 ions having S=1 spin in the ID metal complex chain of the Haldane gap compound. The energy barrier of the spin inversion from the anti-parallel singlet to the parallel triplet state has the relationship with the energy difference between them.

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