Search results
Results from the WOW.Com Content Network
Phosphite esters may be used as reducing agents in more specialised cases. For example, triethylphosphite is known to reduce certain hydroperoxides to alcohols formed by autoxidation [7] (scheme). In this process the phosphite is converted to a phosphate ester. This reaction type is also utilized in the Wender Taxol total synthesis.
In contrast, the solid-angle concept derives both bond length and the perimeter from empirical solid state crystal structures. [ 5 ] [ 6 ] There are advantages to each system. If the geometry of a ligand is known, either through crystallography or computations, an exact cone angle ( θ ) can be calculated.
A bond angle is the angle formed between three atoms across at least two bonds. For four atoms bonded together in a chain, the torsional angle is the angle between the plane formed by the first three atoms and the plane formed by the last three atoms. There exists a mathematical relationship among the bond angles for one central atom and four ...
The P=O bond is very polar with a dipole moment of 4.51 D for triphenylphosphine oxide. [citation needed] Compounds related to phosphine oxides include phosphine imides (R 3 PNR') and related chalcogenides (R 3 PE, where E = S, Se, Te). These compounds are some of the most thermally stable organophosphorus compounds.
Also of importance is the cone angle, which in diphosphines is defined as the average of the cone angle for the two substituents attached to the phosphorus atoms, the bisector of the P–M–P angle, and the angle between each M–P bond. [7] Larger cone angles usually result in faster dissociation of phosphine ligands because of steric crowding.
Trimethyl phosphite is an organophosphorus compound with the formula P(OCH 3) 3, often abbreviated P(OMe) 3.It is a colorless liquid with a highly pungent odor. It is the simplest phosphite ester and finds used as a ligand in organometallic chemistry and as a reagent in organic synthesis.
In the addition of a nucleophile (Nu) attack to a carbonyl, the BD angle is defined as the Nu-C-O bond angle. The BD angle adopted during an approach by a nucleophile to a trigonal unsaturated electrophile depends primarily on the molecular orbital (MO) shapes and occupancies of the unsaturated carbon center (e.g., carbonyl center), and only secondarily on the molecular orbitals of the ...
Phosphodiesterases are enzymes that catalyze the hydrolysis of the phosphodiester bond. These enzymes are involved in repairing DNA and RNA sequences, nucleotide salvage, and in the conversion of cGMP and cAMP to GMP and AMP, respectively. [2] Hydrolysis of the phosphodiester bond also occurs chemically and spontaneously, without the aid of ...