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  2. Biguanide - Wikipedia

    en.wikipedia.org/wiki/Biguanide

    Biguanide (/ b aɪ ˈ ɡ w ɒ n aɪ d /) is the organic compound with the formula HN(C(NH)NH 2) 2. It is a colorless solid that dissolves in water to give a highly basic solution. It is a colorless solid that dissolves in water to give a highly basic solution.

  3. Sigma bond - Wikipedia

    en.wikipedia.org/wiki/Sigma_bond

    There is no more than 1 sigma bond between any two atoms. Molecules with rings have additional sigma bonds, such as benzene rings, which have 6 C−C sigma bonds within the ring for 6 carbon atoms. The anthracene molecule, C 14 H 10, has three rings so that the rule gives the number of sigma bonds as 24 + 3 − 1 = 26. In this case there are 16 ...

  4. Neighbouring group participation - Wikipedia

    en.wikipedia.org/wiki/Neighbouring_group...

    In organic chemistry, neighbouring group participation (NGP, also known as anchimeric assistance) has been defined by the International Union of Pure and Applied Chemistry (IUPAC) as the interaction of a reaction centre with a lone pair of electrons in an atom or the electrons present in a sigma or pi bond contained within the parent molecule but not conjugated with the reaction centre.

  5. Phenyl group - Wikipedia

    en.wikipedia.org/wiki/Phenyl_group

    The bond lengths between carbon atoms in a phenyl group are approximately 1.4 Å. [6] In 1 H-NMR spectroscopy, protons of a phenyl group typically have chemical shifts around 7.27 ppm. These chemical shifts are influenced by aromatic ring current and may change depending on substituents.

  6. Antarafacial and suprafacial - Wikipedia

    en.wikipedia.org/wiki/Antarafacial_and_suprafacial

    For a σ bond, it corresponds to involvement of one "interior" lobe and one "exterior" lobe of the bond. The relationship is suprafacial when the same face of the π system or isolated orbital are involved in the process (think syn). For a σ bond, it corresponds to involvement of two "interior" lobes or two "exterior" lobes of the bond.

  7. Hyperconjugation - Wikipedia

    en.wikipedia.org/wiki/Hyperconjugation

    Hyperconjugation can be used to rationalize a variety of chemical phenomena, including the anomeric effect, the gauche effect, the rotational barrier of ethane, the beta-silicon effect, the vibrational frequency of exocyclic carbonyl groups, and the relative stability of substituted carbocations and substituted carbon centred radicals, and the thermodynamic Zaitsev's rule for alkene stability.

  8. Sigmatropic reaction - Wikipedia

    en.wikipedia.org/wiki/Sigmatropic_reaction

    Sigmatropic rearrangements are concisely described by an order term [i,j], which is defined as the migration of a σ-bond adjacent to one or more π systems to a new position (i−1) and (j−1) atoms removed from the original location of the σ-bond. [3]

  9. Guanidine - Wikipedia

    en.wikipedia.org/wiki/Guanidine

    The general structure of a guanidine. Guanidines are a group of organic compounds sharing a common functional group with the general structure (R 1 R 2 N)(R 3 R 4 N)C=N−R 5. The central bond within this group is that of an imine, and the group is related structurally to amidines and ureas.