Naphthalene anion

The metalation of naphthalene 8-substituted by both an ethyl group or polyisoprene chain (PIP) is completely similar as established by the titration of the carbanions formed and the UV analysis of the reaction medium (21, 22, 25). Accordingly the naphthalene radical anion, naphthalene dianion and its further isomerization by hydrogen transfer sure successively observed and the final stage of the metalation can be represented by the following structure ... 

Naphthalene Naphthalene radical anion Naphthalenated electron... 

Aromatic Radical Anions and Anions Naphthalene radical anion... 

Benzene charge density on anion Naphthalene charge density on anion... 

The explanation offered by the authors is that the MIP was cross-reactive for naphthalene sulfonates. However, at pH 2.3, only the naphthalene sulfonates were anionic (pfCa 0.5-0.6). It is quite plausible that in this example, molecular recognition was predominantly an anion-exchange mechanism, and that this overshadowed the influence of any molecularly imprinted cavities. In this way, the MeOH wash step could be seen to have disrupted non-covalent, non-ionic interactions, leaving behind the anionic naphthalene sulfonates, which were retained much more strongly via ionic interactions with the protonated pyridyl moieties. Unfortunately, this is always a poten-... 

Electron Biphenyl anion Naphthalene Rigid aliphatic 0.56 44... 

Figure 8-18 ESR splitting constants in gauss versus HMO unpaired spin densities. The systems are fused ring alternant hydrocarbon radical anions (naphthalene, anthracene, tetracene, pyrene). The underlined point is thought to result from negative spin density. (Data from Streitwieser [7].)...

CHART 14 Inverse sandwiches of anionic naphthalene yttrium and lutetium complexes reported... 

Kimizuka s group reported that aqueous dispersion of cationic L-glutamate derivatives 39 and 40 with two alkyl tails gives fibrous nanoassemblies with the bilayer structure (Fig. 22). When anionic naphthalene dye 41 was added to the aqueous bilayer of 40 with long undecyl tails, immediate precipitation occurred. Apparently, formation of the hydrophobic ion-pair destabilizes the long-chained ammonium bilayer of 40. On the other hand, 39 with short octyl tails formed a transparent hydrogel in the presence of anionic dye 41... 

For example, naphthalene radical anion L -I with counterion (Li, ). 

Sodium naphthalene [25398-08-7J and other aromatic radical anions react with monomers such as styrene by reversible electron transfer to form the corresponding monomer radical anions. Although the equihbtium (eq. 10)... 

Aromatic radical anions, such as lithium naphthalene or sodium naphthalene, are efficient difunctional initiators (eqs. 6,7) (3,20,64). However, the necessity of using polar solvents for their formation and use limits their utility for diene polymerization, since the unique abiUty of lithium to provide high 1,4-polydiene microstmcture is lost in polar media (1,33,34,57,63,64). Consequentiy, a significant research challenge has been to discover a hydrocarbon-soluble dilithium initiator which would initiate the polymerization of styrene and diene monomers to form monomodal a, CO-dianionic polymers at rates which are faster or comparable to the rates of polymerization, ie, to form narrow molecular weight distribution polymers (61,65,66). 

The most widely used pitch control method is the addition of pitch dispersants, which can be either organic, ie, typically anionic polymers such as naphthalene sulfonates, ligninsulfonates, and polyacrylates (33,34), or inorganic, ie, typically clay or talc. The polymers maintain the pitch as a fine dispersion in the pulp, preventing agglomeration and potential deposition on the paper machine or the sheet. When talc, clay, or other adsorbent fillers are added to the furnish, moderate amounts of pitch can adsorb on these materials, producing a nontacky soHd that can be retained in the sheet. 

Generally, phenols (as the phenolate anion) couple more readily than amines, and members of the naphthalene series more readily than the members of the benzene series. 

The process of anionic polymerisation was first used some 60 or more years ago in the sodium-catalysed production of polybutadiene (Buna Rubbers). Typical catalysts include alkali metals, alkali metal alkyls and sodium naphthalene, and these may be used for opening either a double bond or a ring structure to bring about polymerisation. Although the process is not of major importance with the production of plastics materials, it is very important in the production of synthetic rubbers. In addition the method has certain special features that make it of particular interest. 

Meyers has demonstrated that chiral oxazolines derived from valine or rert-leucine are also effective auxiliaries for asymmetric additions to naphthalene. These chiral oxazolines (39 and 40) are more readily available than the methoxymethyl substituted compounds (3) described above but provide comparable yields and stereoselectivities in the tandem alkylation reactions. For example, addition of -butyllithium to naphthyl oxazoline 39 followed by treatment of the resulting anion with iodomethane afforded 41 in 99% yield as a 99 1 mixture of diastereomers. The identical transformation of valine derived substrate 40 led to a 97% yield of 42 with 94% de. As described above, sequential treatment of the oxazoline products 41 and 42 with MeOTf, NaBKi and aqueous oxalic acid afforded aldehydes 43 in > 98% ee and 90% ee, respectively. These experiments demonstrate that a chelating (methoxymethyl) group is not necessary for reactions to proceed with high asymmetric induction. 

Interest in this reaction was revived when the relevance of a carbene mechanism was realized, particularly following the demonstration (cf. SectionI,B) of a similar ring expansion of indene to 2-chloro-naphthalene by dichlorocarbene via the cyclopropane adduct. Indeed, at this time Nakazaki suggested that these reactions occurred by the addition of dichlorocarbene to the indolyl anion and subsequent rearrangement to the indolenine and, with loss of chloride ion, to the quinoline [Eq. (12)]. The preference of dichlorocarbene for... 

Cations are more subject to ring-opening than are neutral species or anions. Thus ring-opening (slow) has been observed in the cations but not in the neutral species of 1,3,5-, 1,3,7-, and 1,3,8-triazanaph-thalene at 20° it is followed by further degradation. 1,3,6-Triaza-naphthalene decomposes much faster than its isomers in acidic solution, but follows the usual sequence, 47 49,... 

Substituted isoquinolinium-olates are isoconjugate with the methyl-naphthalene anion as shown in Scheme 14. Joining negative structure elements—the olate function—to unstarred positions of the isoconjugate... 

Methylisoquinolinium 2-carboxylate (230), originally prepared by Quast (70LA64), was recently identified as a defensive betaine from Photuris versicolor fireflies (99JNP378). It is a pseudo-cross-conjugated mesomeric betaine isoconjugate to the odd alternant hydrocarbon 2-isopropenyl-naphthalene anion which is an odd alternant hydrocarbon anion. This compound therefore is a member of class 13, which is very rare. The UV absorption maxima Imax (methanol) were found at 235 (4.35), 320 (shoulder, 3.97), and 326 (3.99) nm. This compound undergoes similar reactions as Homarine 19 (Scheme 75). The NMR data are presented in Table VIII. 

Resolution (enantiomers), 307-309 Resonance, 43-47 acetate ion and, 43 acetone anion and. 45 acyl cations and, 558 allylic carbocations and, 488-489 allylic radical and, 341 arylamines and, 924 benzene and, 44. 521 benzylic carbocation and, 377 benzylic radical and, 578 carbonate ion and. 47 carboxylate ions and, 756-757 enolate ions and, 850 naphthalene and, 532 pentadienyl radical and. 48 phenoxide ions and, 605-606 Resonance effect, 562 Resonance forms, 43... 

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