Molecular vise

Database analysis and molecular mechanics were used to determine the conformational flexibility of tridentate scorpionate ligands. It has been reported that tris(pyrazolyl)borate ligands act like molecular vises, opening their tripodal structure for larger metals and closing around smaller metal ions. The Tpx ligand conformation... 

The concept of molecular vise using a compressible mercury sessile drop is described. This drop represents a micro-Langmuir-Blodgett experiment in which thin films of adsorbates can be examined in various stages of surface compression. The macroscopic phase transitions of an octanethiol surface film during the compression/expansion regime are observed visually, and STM images of the mercury/air interface are obtained before and after thiol deposition. 

Figure 1. The "molecular vise" concept. Excess of the clamping host molecule is co-deposited on an expanded mercury drop together with a "guest" molecule present in low concentration. Upon compression the "guest" molecule is immobilized in the condensed monolayer formed by the surrounding host molecules.

The term dn/dc refers to the change in RI of a polymer relative to its concentration. The LS detector responds to M, the Vise detector responds to the intrinsic viscosity ([ ]). which is inversely proportional to molecular density, and the Rl detector monitors concentration (C). A single narrow standard is used to determine the offset constants related to the interdetector volume for a given three-detector system. Either C or dnJdc of a polymer sample must be known a priori in order to calculate the other variable using the RI detector (Eq. 3). Once both dnidc and C are known, the LS and VISC (Eqs. 1 and 2) can be solved to determine M and [77], respectively, for a polymer sample.Structural information, such as chain flexibility, branching, and intramolecular interactions are all related to [7/]. Several key polymer properties related to [77] are as follows ... 

Molecular Reasoning exercises A More Challenging exercises Unless othen/vise noted, all content on this page is Cengage Learning. 

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