Synonyms for diars or Related words with diars

methylborane              dimethylborane              bipy              diphosphane              dirhenium              ethylborane              dmgh              monophosphine              dimetal              diazabutadiene              disiamylborane              aquo              dicopper              dimesitylborane              salophen              opph              nbh              trianionic              bnh              opnp              gallane              scorpionate              uranocene              mobr              phosphane              bdpp              nibr              trimethylborane              ttfa              chlorobis              selenourea              pmdta              dicyclohexylborane              diketonato              tmhd              dmpz              divanadate              nibdpp              methylidyne              aubr              diarsenate              trialkylborane              dimolybdenum              pcy              aminoborane              oxoiron              alkoxyaluminium              homoleptic              zrh              dioxygenyl             



Examples of "diars"
Diars is a bidentate ligand used in coordination chemistry. It was first described in 1939, but was popularized by R. S. Nyholm for its ability to stabilize metal complexes with unusual oxidation states and coordination numbers, e.g. TiCl(diars). High coordination numbers arise because diars is fairly compact and the As-M bonds are long, which relieves crowding at the metal center. In terms of stabilizing unusual oxidation states, diars stabilizes Ni(III), as in [NiCl(diars)]Cl.
Of historical interest is the supposedly diamagnetic [Ni(diars)](ClO), obtained by heating nickel perchlorate with diars. Octahedral "d" complexes characteristically have triplet ground states, so the diamagnetism of this complex was puzzling. Later by X-ray crystallography, the complex was shown to be pentacoordinate with the formula [Ni(triars)(diars)](ClO), where triars is the tridentate ligand [CHAs(CH]As(CH), arising from the elimination of trimethylarsine.
It is a colorless liquid. Oxygen converts diars to the dioxide, CH(As(CH)O).
One of Nyholm’s early successes was the preparation of an octahedral complex of trivalent nickel [Ni(diars)Cl]Cl, by aerial oxidation of the red salt of bivalent nickel [Ni(diars)]Cl. He also described stable complexes of quadrivalent nickel such as the deep blue [Ni(diars)Cl] [ClO], by nitric acid oxidation of the trivalent complex. This stabilisation of higher oxidation states became significant in the Nyholm-Rail reaction where the ditertiary arsine, diars undergoes a condensation reaction to a tritertiary arsine, triars. Nyholm prepared examples of divalent octahedral complexes of the type M(diars)X, where X is Cl, Br or I, and M is Cr, Mn, Fe, Co, Ni, Mo, Tc, Ru, Pd, W, Re, Os, and Pt.
Diars is prepared by the reaction of "ortho"-dichlorobenzene and sodium dimethylarsenide:
1,2-Bis(dimethylarsino)benzene (diars) is the organoarsenic compound with the formula CH(As(CH)). The molecule consists of two dimethylarsino groups attached to adjacent carbon centers of a benzene ring. It is a chelating ligand in coordination chemistry. This colourless oil is commonly abbreviated "diars."
Related, but non-chelating organoarsenic ligands include triphenylarsine and trimethylarsine. Work on diars preceded the development of the chelating diphosphine ligands such as dppe, which are now prevalent in homogeneous catalysis.
Symmetrical organoarsenic(III) compounds, e.g. trimethylarsine and triphenylarsine, are commonly used as ligands in coordination chemistry. They behave like phosphine ligands, but are less basic. The diarsine CH(As(CH)), known as diars, is a chelating ligand. Thorin is an indicator for several metals.
Many of these divalent complexes are sensitive to aerial oxidation. The chromium complex is oxidized by water. Indeed, previous attempts to prepare Cr(diars)X had failed. The chromium compounds were eventually synthesized by his co-worker Anthony Nicholl Rail only a month before Nyholm’s death, using rigorous air-free techniques.
Nyholm's research in inorganic chemistry was primarily concerned with the preparation of transition metal compounds, particularly those involving organo-arsenic ligands. His interest in organoarsenic chemistry was fostered at the University of Sydney by George Joseph Burrows (1888–1950). Using the strong chelating ligand diars, Nyholm demonstrated a range of oxidation states and coordination numbers for several of the transition metals. Nyholm noted that the term ‘unusual valence state’ had an ‘historical, but not chemical significance.’ ‘The definition of usual oxidation state refers to oxidation states that are stable in environments made up of those chemical species that were common in classical inorganic compounds, e.g. oxides, water and other simple oxygen donors, the halogens, excluding fluorine, and sulphur. Nowadays, however, such species constitute only a minority of the vast number of donor atoms and ligands that can be attached to metal.’