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Propadiene (/ p r oʊ p ə ˈ d aɪ iː n /) or allene (/ ˈ æ l iː n /) is the organic compound with the formula H 2 C=C=CH 2. It is the simplest allene, i.e. a compound with two adjacent carbon double bonds. [3] As a constituent of MAPP gas, it has been used as a fuel for specialized welding.
Expressing resonance when drawing Lewis structures may be done either by drawing each of the possible resonance forms and placing double-headed arrows between them or by using dashed lines to represent the partial bonds (although the latter is a good representation of the resonance hybrid which is not, formally speaking, a Lewis structure ...
2 cf 2 → f 2 c=cf 2 The insertion of carbenes into C–H bonds has been exploited widely, e.g. the functionalization of polymeric materials [ 23 ] and electro-curing of adhesives . [ 24 ] Many applications rely on synthetic 3-aryl-3-trifluoromethyl diazirines [ 25 ] [ 26 ] (a carbene precursor that can be activated by heat, [ 27 ] light, [ 26 ...
Contributing structures of the carbonate ion. In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or forms, [1] also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory.
Structure of allylpalladium chloride dimer. Transition-metal allyl complexes are coordination complexes with allyl and its derivatives as ligands.Allyl is the radical with the connectivity CH 2 CHCH 2, although as a ligand it is usually viewed as an allyl anion CH 2 =CH−CH 2 −, which is usually described as two equivalent resonance structures.
Structure of (C 5 H 5) 2 TaCH 3 (CH 2), as determined by X-ray crystallography. [8] The Ta−CH 3 and Ta=CH 2 distances are 2.37 and 2.04 Å, respectively. Color code: blue = Ta, gray = C, white = H. Schrock carbenes do not have π-accepting ligands on the metal centre. They are often called alkylidene complexes.
A group of the structure R 2 C=C=CR− is called allenyl, while a substituent attached to an allene is referred to as an allenic substituent (R is H or some alkyl group). In analogy to allylic and propargylic , a substituent attached to a saturated carbon α (i.e., directly adjacent) to an allene is referred to as an allenylic substituent.
For example, this structure is found in the compound [Ni 2 (NCO) 2 2](BPh 4) 2. In this compound both the Ni−N−C unit and Ni−O−C unit are bent, even though in the first case donation is through the nitrogen atom.