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Topic: Nucleophile

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	Carboxylic Acid Derivatives
		The nucleophilic oxygen uses its electrons to make a new bond to the electrophilic carbonyl carbon while the pi bond's electrons move to the carbonyl oxygen.
		The overall substitution process occurs by an addition-elimination mechanism which begins with a nucleophilic addition to the carbonyl group and finishes with the departure of an atom with the bonding pair of electrons.
		Notice that the nucleophilic attack is preceded by protonation of the carbonyl oxygen.
	chemistry2.csudh.edu /rpendarvis/carboxder.html (1158 words)

	Nucleophile: Definition and Links by Encyclopedian.com
		In chemistry, a nucleophile (literally nucleus-lover) is a reagent attracted to nuclei that participates in a chemical reaction by donating electrons in order to bond to a substance.
		Nucleophiles take part in nucleophilic substitution, whereby a nucleophile becomes attracted to the nucleus of an element and displaces the group it is bonded to.
		Nucleophilic is an adjective that describes the affinity of a nucleophile to the nuclei, while nucleophilicity refers to the nucleophilic character.
	www.encyclopedian.com /nu/Nucleophile.html (196 words)

	Nucleophile Summary
		In the case of nucleophilic substitution reactions involving the polar carbon-halogen bond of an alkyl halide and a negative nucleophile, the nucleophile seeks the carbon atom that bears the halogen atom.
		Nucleophiles may take part in nucleophilic substitution, whereby a nucleophile becomes attracted to a full or partial positive charge on an element and displaces the group it is bonded to.
		Nucleophilic is an adjective that describes the affinity of a nucleophile to the nuclei, while nucleophilicity or nucleophile strength refers to the nucleophilic character.
	www.bookrags.com /Nucleophile (1314 words)

	Tiffany's Chime
		The nucleophile could approach the substrate from the same side as the leaving group, one group exchanging for the other, which is called frontside displacement.
		Charge: Because nucleophilic attack is characterized by the formation of a bond with an electrophilic carbon center, the more negative the attacking species the faster the reaction should be.
		As the nucleophile approaches the electrophilic carbon, the latter rehybridizes, and the electron pair of the pi bond moves over to the oxygen, thereby producing the characteristic "tetrahedral intermediate, an alkoxide ion.
	www.ucalgary.ca /~rauk/saunders.html (1087 words)

	Nucleophile - Biocrawler (Site not responding. Last check: )
		A nucleophile participates in a chemical reaction by donating electrons to a species known as an electrophile in order to form a chemical bond.
		Nucleophiles may take part in nucleophilic substitution, whereby a nucleophile becomes attracted to a full or partial positive charge on an element and displaces the group it is bonded to.
		Nucleophilic is an adjective that describes the affinity of a nucleophile to the nuclei, while nucleophilicity or nucleophile strength refers to the nucleophilic character.
	www.biocrawler.com /encyclopedia/Nucleophile (264 words)

	Sn2 Reaction Mechanism
		This reaction works the best with methyl and primary halides because bulky alkyl groups block the backside attack of the nucleophile, but the reaction does work with secondary halides (although it is usually accompanied by elimination), and will not react at all with tertiary halides.
		Because of the backside attack of the nucleophile, inversion of configuration occurs.
		Nucleophiles: A good nucleophile is required since it is involved in the rate-determining step.
	www.chemhelper.com /sn2.html (170 words)

	N and O
		A nucleophile (or nucleophilic reagent) is a reagent that forms a bond to its reaction partner (the electrophile) by donating both bonding electrons.
		A "nucleophilic substitution reaction" is a heterolytic reaction in which the reagent supplying the entering group acts as a nucleophile.
		(2) The relative reactivity of a nucleophilic reagent.
	www.chem.qmul.ac.uk /iupac/gtpoc/NO.html (2047 words)

	Nucleophiles (Site not responding. Last check: )
		Nucleophilicity is a measure of how fast a Lewis base displaces a leaving group.
		When the nucleophilic atoms of two reagents are in the same row of the periodic table, the relative nucleophilicty of the reagents is directly related to the relative basicity of the two reagents.
		If the nucleophile can allow some of its electron cloud to distort closer to the electrophile (usually a carbon atom), the transition state is more stable and the reaction will proceed more rapidly.
	www.cem.msu.edu /~parrill/nucleophile.html (426 words)

	Center for Green Chemistry and Technology: Purpose
		A strategy to effecting ether hydrolysis therefore is to target nucleophilic attack at this carbon center in conjunction with increasing the electrophilicity at this carbon by coordinating a metal cation to the ether oxygen.
		Good nucleophiles such as cyanide, iodide, or thiolate will likely be effective for the heterolytic cleavage of the oxygen-carbon bond in ethers, but subsequent hydrolysis of the alkyl-nucleophile bond will be less easily accomplished.
		Higher nucleophilic strength, or higher electrophilicity of the ether carbon induced by metal ion complexation, may be required to achieve the hydrolytic cleavage of these rings.
	www.orgs.ttu.edu /greenchemistry/research (4923 words)

	Addition of Water
		It is attacked by the oxygen of water, using the oxygen's unshared pair.
		In our example, the oxygen atom is serving as a nucleophile.
		A summary of the reactivity of the carbonyl group is that electrophiles attack the oxygen; nucleophiles attack the carbon.
	chemistry2.csudh.edu /rpendarvis/carbaddn.html (1482 words)

	Amazon.com: "tyrosine nucleophile": Key Phrase page
		The roles of the active-site residues other than the tyrosine nucleophile are becoming clear.
		The Arg- His-Arg triad coordinates the scissile phosphate in the covalent intermediate structure (24, 26).
		The primary distinction between the active and inactive states is in the orientation of the tyrosine nucleophile.
	www.amazon.com /phrase/tyrosine-nucleophile (320 words)

	VLU: SN1 - First-order Nucleophilic Substitution - Influence of the Nucleophile - ChemgaPedia
		Obviously, sodium azide is a more effective nucleophile than methanol is. Its reaction with carbocations is therefore much more rapid than that of methanol would be.
		The reaction rate is determined by the individual reaction step that displays the transition state richest in energy.
		The more efficient nucleophile induces a lower-energy transition state, which in turn determines the product distribution.
	www.chemgapedia.de /vsengine/vlu/vsc/en/ch/12/oc/vlu_organik/substitution/sn_1/sn_1.vlu/Page/vsc/en/ch/12/oc/substitution/sn_1/nucleophil/nucleophil.vscml.html (168 words)

	Alkyl Halide Reactivity
		Nucleophilicity is thereby related to the relative rate of substitution reactions at the halogen-bearing carbon atom of the reference alkyl halide.
		As a covalent bond begins to form between the nucleophile and the carbon, the carbon halogen bond weakens and stretches, the halogen atom eventually leaving as an anion.
		This represents a point on the trajectory the nucleophile must follow if it is to bond to the back-side of the carbon atom, displacing bromide anion from the front face.
	www.cem.msu.edu /~reusch/VirtualText/alhalrx1.htm (2578 words)

	The Sn2 Reaction (Site not responding. Last check: )
		In this reaction the nucleophile attacks the reactant from the backside of the leaving group, while simultaneously displacing the leaving group.
		When the nucleophile attacks the carbon, the bond between the nucleophile and carbon will strengthen while the bond to the leaving group weakens.
		During the transitional state the carbon is partially bonded to both the nucleophile and the leaving group.
	facultystaff.vwc.edu /~jeaster/courseinfo/Tutorials/reactions/Sn2.htm (318 words)

	Nucleophilic Substitution (SN1 / SN2)
		Nucleophilic substitution is the reaction of an electron pair donor (the nucleophile, Nu) with an electron pair acceptor (the electrophile).
		Since the nucleophile is free to attack from either side, this reaction is associated with racemization.
		A weaker nucleophile is not as effective in the backside attack, since this location is sterically shielded, especially in the case of tertiary substrates.
	www.organic-chemistry.org /namedreactions/nucleophilic-substitution-sn1-sn2.shtm (686 words)

	Nucleophile - Glasgledius (Site not responding. Last check: )
		In chemistry, a nucleophile (literally nucleus-lover) is a reagent attracted to nuclei that participates in a chemical reaction by donating electrons in order to bond to a substance.
		Nucleophiles take part in nucleophilic substitution, whereby a nucleophile becomes attracted to the nucleus of an element and displaces the group it is bonded to.
		Nucleophilic is an adjective that describes the affinity of a nucleophile to the nuclei, while nucleophilicity refers to the nucleophilic character.
	www.glasglow.com /E2/nu/Nucleophile.html (159 words)

	Untitled Document (Site not responding. Last check: )
		The nucleophile with a large negative charge is attracted to the backside of the C-X bond due to partial positive charge present there.
		Nucleophiles should be thought of in three categories: strong, medium and weak.
		All the nucleophiles in the table react with methyl and primary alkyl halides predominantly via the SN2 mechanism (remember tBuOK is not a nucleophile).
	www.enc.edu /~timothy.t.wooster/courses/CH321/lecturenotes/chapter6/SN2.htm (311 words)

	[No title]
		An electon pair from the nucleophile forms a new bond to the carbonyl carbon, and this forces two electrons from the carbon-oxygen double bond to move onto oxygen.
		With nucleophiles such as amines, though, the oxygen component can be completely expelled via loss of an equivalent of water to form a double bond between carbon and the nucleophile (an imine if the nucleophile was an amine).
		A nucleophilic addition to a carbonyl compound is reversible when the nucleophile is also a good leaving group.
	www.chem.wisc.edu /~newtrad/CurrRef/AIDStopic/AIDS.AldKetRxns.html (2217 words)

	Explaining nucleophilic substitution between halogenoalkanes and water
		A nucleophile is a species (an ion or a molecule) which is strongly attracted to a region of positive charge in something else.
		The attack on the halogenoalkane is therefore by one of the lone pairs on the oxygen.
		S stands for substitution, N for nucleophilic, and the 2 is because the initial stage of the reaction involves two species - the bromoethane and the water.
	www.chemguide.co.uk /mechanisms/nucsub/watertt.html (915 words)

	elec_nuc.html
		Therefore identification of electrophiles and nucleophiles is a critical organic chemistry survival skill.
		Solution 1: A nucleophile is a molecule or ion that donates an electron pair to form a new covalent bond.
		Because nucleophile must react with an electrophile that leaves the other molecule (a chlorosulfite ester) to be the electrophile.
	web.chem.ucla.edu /~harding/tutorials/elec_nuc/elec_nuc.html (872 words)

	SNTWO (Site not responding. Last check: )
		The reason that inversion occurs is because when the big nucleophile comes in to attack the carbon(remember the big leaving group has not left yet) it must come in from the side where it has the most room.
		When the nucleophile attacks and is beginning to form a bond with the carbon, the leaving group is beginning to leave.
		If the nucleophile is surrounded by a cage formed by the protic solvent it is going to have a difficult time coming in and attacking the carbon.
	www.organicchemistryreview.com /SNTWO.html (1306 words)

	Sn2
		State the correlation between the changes in base strength and nucleophilic reactivity for the ions shown in Figure 1: For reagents in which the nucleophilic atom is an oxygen, the nucleophilic reactivity increases as the strength of the base
		The relative nucleophilicities of the halide ions depend dramatically upon the solvent.
		In this reaction, the tetraalkyl ammonium halide acts as both a source of the nucleophile and as the substrate.
	www.usm.maine.edu /~newton/Chy251_253/Lectures/Sn2Nucleophiles/Sn2Nucleophiles.html (626 words)

	What is nucleophilic addition / elimination?
		The nucleophiles that we shall be looking at all depend on lone pairs on either an oxygen atom or a nitrogen atom.
		Since the initial attack is by a nucleophile, and the overall result is substitution, it would seem reasonable to describe the reaction as nucleophilic substitution.
		As the lone pair on the nucleophile approaches the fairly positive carbon in the acyl chloride, it moves to form a bond with it.
	www.chemguide.co.uk /mechanisms/addelim/whatis.html (796 words)

	Nucleophile Information Center - why is nitrogen a better nucleophile than oxygen
		In chemistry, a nucleophile (literally nucleus lover) is a deamination nucleophile reagent which is attracted to centres of positive charge.
		Nucleophiles may take part in nucleophilic substitution, whereby a nucleophile becomes attracted to a full or partial positive charge on an element and displaces the naoh nucleophile secondary group it is bonded to.
		An ambident nucleophile is one that can attack from two or more places, resulting in two or more products.
	www.scipeeps.com /Sci-Chemistry_Topics_Mi_-_O/Nucleophile.html (348 words)

	Nucleophilic Substitution Reactions
		Nucleophilic substitution will be explored in much more detail in chapter 8.
		In the reactions of alcohols with HX, the reactivity trend of HI > HBr > HCl > HF is not due to the nucleophilicity of the halide ion but the acidity of HX which is involved in generating the leaving group prior to the rate determining step.
		Since the nucleophile is involved in the rate determining step, the nature of the nucleophile is very important in an S
	www.mhhe.com /physsci/chemistry/carey/student/olc/ch04nucle.html (1065 words)

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