Nucleophilic reactivity and electrocatalytic reduction of halogenated organic compounds by nickel: O -phenylenedioxamidate complexes

Article abstract of DOI:10.1039/c6dt02349e

A growing number of halogenated organic compounds have been identified as hazardous pollutants. Although numerous advanced oxidative processes have been developed to degrade organohalide compounds, reductive and nucleophilic molecular approaches to dehalo

Full text of DOI:10.1039/c6dt02349e

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View Article Online
DOI: 10.1039/C6DT02349E
DaltonꢀTransactionsꢀ
ꢀ
ARTICLEꢀ
Nucleophilicꢀreactivityꢀandꢀelectrocatalyticꢀreductionꢀofꢀ
halogenatedꢀorganicꢀcompoundsꢀbyꢀnickelꢀo-
phenylenedioxamidateꢀcomplexesꢀꢀ
Receivedꢀ00thꢀJanuaryꢀ20xx,ꢀ
Acceptedꢀ00thꢀJanuaryꢀ20xxꢀ
a
a
a
*,a,b,cꢀ
SivaꢀPrasadꢀDas, ꢀRakeshꢀGanguly, ꢀYongxinꢀLi, ꢀandꢀHanꢀSenꢀSoo
DOI:ꢀ10.1039/x0xx00000xꢀ
www.rsc.org/ꢀ
Aꢀgrowingꢀnumberꢀofꢀhalogenatedꢀorganicꢀcompoundsꢀhaveꢀbeenꢀidentifiedꢀasꢀhazardousꢀpollutants.ꢀAlthoughꢀnumerousꢀ
advancedꢀ oxidativeꢀ processesꢀ haveꢀ beenꢀ developedꢀ toꢀ degradeꢀ organohalideꢀ compounds,ꢀ reductiveꢀ andꢀ nucleophilicꢀ
molecularꢀ approachesꢀ toꢀ dehalogenateꢀ organicꢀ compoundsꢀ haveꢀ rarelyꢀ beenꢀ reported.ꢀ Inꢀ thisꢀ manuscript,ꢀ weꢀ employꢀ
2
nickel(II)ꢀ –ateꢀ complexesꢀ bearingꢀ theꢀ o-phenylenebis(N-methyloxamide)ꢀ (Me opba)ꢀ tetraanionicꢀ ligandꢀ asꢀ nucleophilicꢀ
reagentsꢀthatꢀcanꢀreactꢀwithꢀalkylꢀhalidesꢀ(methylꢀupꢀtoꢀtheꢀbulkyꢀisobutyl)ꢀbyꢀO-alkylationꢀtoꢀgiveꢀtheirꢀrespectiveꢀimidateꢀ
products.ꢀ Fourꢀ newꢀ nickel(II)ꢀ complexesꢀ haveꢀ beenꢀ characterizedꢀ byꢀ X-rayꢀ crystallography,ꢀ andꢀ theꢀ salientꢀ structuralꢀ
–
1
parametersꢀandꢀFT-IRꢀvibrationalꢀbandsꢀ(~1655ꢀcm )ꢀconcurꢀwithꢀtheirꢀassignmentꢀasꢀtheꢀimidateꢀtautomericꢀform.ꢀToꢀtheꢀ
II
bestꢀofꢀourꢀknowledge,ꢀthisꢀisꢀtheꢀfirstꢀreportꢀonꢀtheꢀnucleophilicꢀreactivityꢀofꢀNi (Me
2
opba)ꢀwithꢀhalogenatedꢀorganicꢀ
compounds.ꢀTheꢀparentꢀnickel(II)ꢀMe
2
opbaꢀcomplexꢀexhibitsꢀreversibleꢀelectrochemicalꢀoxidationꢀandꢀreductionꢀbehavior.ꢀ
II
Asꢀ aꢀ proofꢀ ofꢀ concept,ꢀ Ni (Me
2
opba)ꢀ andꢀ itsꢀ alkylatedꢀ congenersꢀ wereꢀ utilizedꢀ forꢀ theꢀ electrocatalyticꢀ reductionꢀ ofꢀ
chloroform,ꢀasꢀaꢀrepresentative,ꢀsimpleꢀpoly-halogenatedꢀorganicꢀmoleculeꢀthatꢀcouldꢀariseꢀfromꢀoxidativeꢀtreatmentꢀofꢀ
organicꢀcompoundsꢀbyꢀchlorination.ꢀModestꢀturnoverꢀnumbersꢀofꢀupꢀtoꢀ6ꢀwereꢀrecorded,ꢀwithꢀdichloromethaneꢀidentifiedꢀ
asꢀoneꢀofꢀtheꢀpossibleꢀproducts.ꢀFutureꢀeffortsꢀareꢀdirectedꢀtowardsꢀbulkierꢀ–ateꢀcomplexesꢀthatꢀpossessꢀmetal-centeredꢀ
insteadꢀofꢀligand-centeredꢀnucleophilicꢀactivityꢀtoꢀcreateꢀmoreꢀeffectiveꢀelectrocatalystsꢀforꢀtheꢀreductionꢀofꢀhalogenatedꢀ
organicꢀcompounds.ꢀꢀ ꢀ
commonꢀ halogenatedꢀ organicꢀ compoundsꢀ areꢀ listedꢀ inꢀ Chartꢀ
S1ꢀ (Electronicꢀ Supplementaryꢀ Information,ꢀ ESI).ꢀ Forꢀ example,ꢀ
chloroformꢀ isꢀ aꢀ commonꢀ by-productꢀ fromꢀ chlorineꢀ
Introductionꢀ
Thereꢀ hasꢀ beenꢀ constantꢀ interestꢀ inꢀ theꢀ utilizationꢀ ofꢀ
bioinspiredꢀ redoxꢀ reagentsꢀ toꢀ facilitateꢀ catalyticꢀ processes,ꢀ
27
oxidations, ꢀ whichꢀ hasꢀ beenꢀ linkedꢀ toꢀ theꢀ depressionꢀ ofꢀ theꢀ
28
1-3
centralꢀnervousꢀsystem,ꢀmentalꢀconfusion,ꢀandꢀevenꢀcancer. ꢀ
Inꢀthisꢀcontext,ꢀelectrocatalyticꢀhydrogenationꢀorꢀreductionꢀbyꢀ
suchꢀ asꢀ cobalaminꢀ forꢀ chemicalꢀ dehalogenation, ꢀ Ni-
4,ꢀ 5
hydrogenasesꢀforꢀH2ꢀevolution, ꢀandꢀP450ꢀmimicsꢀandꢀnon-
29-32
6,ꢀ7
materialsꢀ hasꢀ beenꢀ foundꢀ toꢀ beꢀ somewhatꢀ effective.
ꢀ
hemeꢀironꢀoxoꢀcomplexesꢀforꢀalkaneꢀC-Hꢀactivation. ꢀRelatedꢀ
toꢀthisꢀcontext,ꢀaꢀnumberꢀofꢀresearchꢀgroupsꢀhaveꢀdescribedꢀ
theirꢀ effortsꢀ inꢀ applyingꢀ bioinspired,ꢀ moreꢀ eco-friendly,ꢀ
molecularꢀ andꢀ electrochemicalꢀ oxidativeꢀ approachesꢀ toꢀ
However,ꢀ thereꢀ hasꢀ beenꢀ aꢀ dearthꢀ ofꢀ researchꢀ onꢀ molecularꢀ
reductiveꢀ orꢀ nucleophilicꢀ proceduresꢀ toꢀ removeꢀ halogenatedꢀ
33
organicꢀcompounds, ꢀwithꢀtheꢀmajorityꢀofꢀeffortsꢀfocusedꢀonꢀ
biotechnologicalꢀ solutionsꢀ toꢀ convertꢀ organicꢀ compoundsꢀ toꢀ
8
-12
degradeꢀ halogenatedꢀ organicꢀ compounds. ꢀ Thisꢀ isꢀ aꢀ timelyꢀ
responseꢀ toꢀ aꢀ dramaticꢀ numberꢀ ofꢀ reportsꢀ thatꢀ haveꢀ latelyꢀ
highlightedꢀ theꢀ detectionꢀ andꢀ persistenceꢀ ofꢀ halogenatedꢀ
34
biogasꢀunderꢀanoxicꢀconditions. ꢀ
Recently,ꢀourꢀteamꢀhasꢀbeenꢀinvolvedꢀinꢀtheꢀdevelopmentꢀ
35,ꢀ 36
1
3-26
organicꢀ compoundsꢀ inꢀ theꢀ environment.
ꢀ Aꢀ fewꢀ ofꢀ theseꢀ ofꢀ solutionsꢀ forꢀ environmentalꢀ applications
ꢀ andꢀ energyꢀ
ꢀutilizingꢀexclusivelyꢀEarth-abundantꢀelements.ꢀWeꢀ
37-39
research
haveꢀ employedꢀ mesoporousꢀ ceriumꢀ oxideꢀ nanomaterialsꢀ forꢀ
theꢀ photocatalyticꢀ oxidativeꢀdegradationꢀofꢀrhodamineꢀB,ꢀviaꢀ
reactiveꢀ oxygenꢀ speciesꢀ suchꢀ asꢀ hydroxylꢀ andꢀ hydroperoxyꢀ
36
radicals. ꢀ Onꢀ theꢀ otherꢀ hand,ꢀ weꢀ haveꢀ exploitedꢀ aꢀ nickelꢀ
salicylaldimineꢀelectrocatalystꢀinꢀitsꢀreducedꢀ–ateꢀformꢀforꢀH2ꢀ
38
evolutionꢀ fromꢀ seawater. ꢀ Withꢀ theseꢀ priorꢀ studies,ꢀ weꢀ
consideredꢀwhetherꢀsuitableꢀnucleophilic,ꢀmolecularꢀcatalystsꢀ
thatꢀinvolveꢀlateꢀfirst-rowꢀtransitionꢀmetalsꢀcanꢀbeꢀdesignedꢀforꢀ
theꢀphoto-ꢀorꢀelectrocatalyticꢀreductionꢀofꢀhalogenatedꢀorganicꢀ
Thisꢀjournalꢀisꢀ©ꢀTheꢀRoyalꢀSocietyꢀofꢀChemistryꢀ2016ꢀ
DaltonꢀTrans.,ꢀ2016,ꢀ00,ꢀ1-3ꢀ|ꢀ1ꢀꢀ
Pleaseꢀdoꢀnotꢀadjustꢀmarginsꢀ

Ple aDs ae lꢀ dt oo nꢀ n To rt aꢀ an d sj ua cs tt ꢀi mo na sr ginsꢀ
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ARTICLEꢀ
DaltonꢀTransactionsꢀ
compounds,ꢀasꢀaꢀdifferentꢀapproachꢀtoꢀdegradeꢀtheseꢀoxidizedꢀ summarizedꢀ inꢀ Tableꢀ 1.ꢀ Theꢀ E1/2ꢀ valuesꢀ ofꢀ –0.27ꢀ andꢀ +0.47ꢀ Vꢀ (vsꢀ
View Article Online
+
III
II
DOI: 10.1039/C6DT02349E
pollutants.ꢀ
Amongꢀ nucleophilic,ꢀ late,ꢀ firstꢀ rowꢀ transitionꢀ metalꢀ
complexes,ꢀ reducedꢀ cobalaminꢀ derivativesꢀ areꢀ reputedꢀ toꢀ beꢀ
Fc /Fc)ꢀcorrespondꢀtoꢀtheꢀNi /Ni ꢀandꢀsubsequentꢀformationꢀofꢀtheꢀ
54
ligandꢀcationꢀradicalꢀrespectively,ꢀasꢀreportedꢀearlier. ꢀHowever,ꢀanꢀ
unreportedꢀnewꢀadditionalꢀwaveꢀwasꢀobservedꢀatꢀE1/2ꢀofꢀ–2.42ꢀV,ꢀ
II
I
II
I
1
whichꢀ mayꢀ beꢀ attributedꢀ toꢀ theꢀ Ni /Ni ꢀ redoxꢀ couple.ꢀ Thisꢀ Ni /Ni ꢀ
redoxꢀ coupleꢀ wasꢀ foundꢀ toꢀ beꢀ reversibleꢀ (Fig.ꢀ 1b).ꢀ Theꢀ twoꢀ smallꢀ
peaksꢀatꢀaroundꢀ-1.20ꢀandꢀ-1.66ꢀVꢀinꢀtheꢀanodicꢀdirectionꢀ(Fig.ꢀ1a)ꢀ
likelyꢀ ariseꢀ fromꢀ solventꢀ degradationꢀ by-productsꢀ uponꢀ applyingꢀ
“
supernucleophilic”ꢀ evenꢀ underꢀ aqueousꢀ conditions. ꢀ Thereꢀ
haveꢀ beenꢀ aꢀ smallꢀ numberꢀ ofꢀ reportsꢀ whereꢀ cobalaminꢀ wasꢀ
usedꢀforꢀdehalogenationꢀreactions.ꢀSomeꢀfunctionalizedꢀTiO2-
2
,ꢀ 3,ꢀ 40
cobalaminꢀ hybridꢀ materials
ꢀ asꢀ wellꢀ asꢀ heme-basedꢀ
ꢀhaveꢀshownꢀactivityꢀforꢀtheꢀdechlorinationꢀofꢀ
,1-bis(4-chlorophenyl)-2,2,2-trichloroethaneꢀ (DDT).ꢀ Otherꢀ
II
I
41,ꢀ 42
reductiveꢀ potentialsꢀ downꢀ toꢀ –3.0ꢀ V,ꢀ beyondꢀ theꢀ Ni /Ni ꢀ redoxꢀ
couple.ꢀ Thisꢀ wasꢀ verifiedꢀ inꢀ aꢀ separateꢀ CVꢀ experimentꢀ whenꢀ theꢀ
potentialꢀwasꢀreversedꢀatꢀ–2.18ꢀV.ꢀUnderꢀthisꢀcondition,ꢀbothꢀsmallꢀ
anodicꢀpeaksꢀwereꢀabsent.ꢀꢀ
composites
1
relatedꢀ reductantsꢀ comprisingꢀ molecularꢀ reactivityꢀ includeꢀ
cobaltꢀphthalocyanine-TiO2ꢀcompositesꢀforꢀdehalogenationꢀofꢀ
43
CHBr3, ꢀ “hydratedꢀ electrons”ꢀ derivedꢀ fromꢀ rutheniumꢀ
Subsequently,ꢀ2ꢀwasꢀmixedꢀwithꢀexcessꢀamountsꢀofꢀalkylꢀiodidesꢀ
44
i
I
tris(bipyridine), ꢀandꢀmetalꢀcarbonylsꢀinꢀtheꢀdechlorinationꢀofꢀ (R-I;ꢀRꢀ=ꢀMe,ꢀEt,ꢀ Pr,ꢀ Bu)ꢀinꢀMeCNꢀatꢀ35ꢀtoꢀ45ꢀºCꢀ(Schemeꢀ1).ꢀAfterꢀatꢀ
45
CCl4ꢀ andꢀ CHCl3. ꢀ Aꢀ commonꢀ themeꢀ amongꢀ theseꢀ rareꢀ leastꢀ72ꢀh,ꢀtheꢀpaleꢀyellowꢀsolutionsꢀofꢀ2ꢀturnedꢀpink.ꢀMoreover,ꢀtheꢀ
examplesꢀ ofꢀ reductiveꢀ dehalogenationꢀ processesꢀ isꢀ theꢀ NMRꢀspectraꢀofꢀtheꢀreactionꢀmixturesꢀindicatedꢀthatꢀtheꢀligandꢀinꢀ
presenceꢀofꢀmoleculesꢀasꢀelectronicꢀreservoirs,ꢀfrequentlyꢀwithꢀ theꢀ complexesꢀ hadꢀ desymmetrized,ꢀ confirmingꢀ thatꢀ 2ꢀ hadꢀ beenꢀ
1,ꢀ3,ꢀ40-46
1
13
lateꢀtransitionꢀmetalꢀ-ateꢀcomplexes.
ꢀꢀ
consumedꢀ inꢀ theꢀ reactionꢀ withꢀ theꢀ alkylꢀ iodides.ꢀ Theꢀ Hꢀ andꢀ Cꢀ
NMRꢀ spectraꢀ suggestedꢀ thatꢀ 2ꢀ hadꢀ beenꢀ alkylatedꢀ toꢀ formꢀ
Inꢀ lightꢀ ofꢀ theseꢀ limitedꢀ numberꢀ ofꢀ relatedꢀ studies,ꢀ weꢀ
soughtꢀaꢀreadilyꢀsynthesized,ꢀmultidentate,ꢀanionicꢀligandꢀthatꢀ
canꢀsupportꢀlateꢀfirst-rowꢀtransitionꢀmetalsꢀasꢀ–ateꢀcomplexes.ꢀ
Theꢀ familyꢀ ofꢀ o-phenylenebis(N-alkyloxamide)ꢀ ligandsꢀ areꢀ
tetraanionicꢀ andꢀ canꢀ beꢀ preparedꢀ inꢀ twoꢀ stepsꢀ fromꢀ
commerciallyꢀavailableꢀreagents.ꢀTheꢀcomplexesꢀcomprisingꢀo-
phenylenebis(N-methyloxamide)ꢀ (Me2opba)ꢀ (1)ꢀ haveꢀ beenꢀ
typicallyꢀCo,ꢀNi,ꢀorꢀCuꢀcompoundsꢀthatꢀhaveꢀbeenꢀappliedꢀasꢀ
oxidativeꢀ catalystsꢀ inꢀ alcoholꢀ oxidation,ꢀ decarboxylation,ꢀ andꢀ
epoxidationꢀ ofꢀ olefins,ꢀ possiblyꢀ dueꢀ toꢀ theꢀ accessibleꢀ higherꢀ
i
i
diamagneticꢀproducts,ꢀ3a-dꢀ(3aꢀ=ꢀMe,ꢀ3bꢀ=ꢀEt,ꢀ3cꢀ=ꢀ Pr,ꢀandꢀ3dꢀ=ꢀ Bu).ꢀ
TheꢀspectraꢀareꢀpresentedꢀinꢀFig.ꢀS5ꢀ–ꢀS12ꢀ(ESI).ꢀCharacteristicꢀpeaksꢀ
forꢀ methoxy,ꢀ ethoxy,ꢀ isopropoxy,ꢀ andꢀ isobutoxyꢀ groupsꢀ wereꢀ
1
observedꢀinꢀtheꢀ HꢀNMRꢀspectraꢀforꢀ3aꢀ–ꢀ3d,ꢀrespectivelyꢀ(Tableꢀ2).ꢀ
TheseꢀresultsꢀstronglyꢀsuggestꢀthatꢀO-alkylationꢀofꢀanꢀamideꢀgroupꢀ
inꢀ2ꢀhadꢀoccurred,ꢀinsteadꢀofꢀalkylationꢀatꢀNiꢀorꢀelsewhereꢀinꢀtheꢀ
ligand.ꢀ Likewise,ꢀ newꢀ peaksꢀ appearedꢀ forꢀ theꢀ methoxy,ꢀ ethoxy,ꢀ
13
isopropoxy,ꢀandꢀisobutoxyꢀgroupsꢀinꢀtheꢀ CꢀNMRꢀspectraꢀofꢀ3a-3d,ꢀ
respectivelyꢀ(Tableꢀ2).ꢀBesidesꢀthese,ꢀdistinctꢀpeaksꢀwereꢀdetectedꢀ
7-54 forꢀeachꢀcarbonꢀofꢀtheꢀamidesꢀandꢀaromaticꢀgroupsꢀdueꢀtoꢀtheꢀasymmetryꢀꢀ
4
valentꢀintermediatesꢀmediatedꢀbyꢀtheꢀtetraanionicꢀligand.
Althoughꢀaꢀnumberꢀofꢀnucleophilicꢀ–ateꢀcomplexesꢀcomprisingꢀ
ꢀ
55-63
dꢀ transitionꢀ metalsꢀ exist,
3 ꢀ however,ꢀ toꢀ theꢀ bestꢀ ofꢀ ourꢀ
knowledge,ꢀtheꢀnucleophilicꢀO-alkylationꢀreactivityꢀofꢀMe2opbaꢀ
inꢀ –ateꢀ complexesꢀ hasꢀ notꢀ beenꢀ reportedꢀ soꢀ far.ꢀ Herein,ꢀ weꢀ
II
presentꢀ forꢀ theꢀ firstꢀ timeꢀ Ni (Me2opba)ꢀ asꢀ aꢀ nucleophilicꢀ
reagentꢀ inꢀ reactionsꢀ withꢀ halogenatedꢀ organicꢀ compounds.ꢀ
Theꢀproductsꢀisolatedꢀfromꢀtheꢀstoichiometricꢀreactionsꢀhaveꢀ
beenꢀ characterizedꢀ byꢀ singleꢀ crystalꢀ X-rayꢀ structuralꢀ analysis,ꢀ
electrochemistry,ꢀ andꢀ FT-IRꢀ spectroscopy.ꢀ Asꢀ aꢀ proofꢀ ofꢀ
principle,ꢀ weꢀ haveꢀ includedꢀ resultsꢀ forꢀ theꢀ electrocatalyticꢀ
ꢀ
reductionꢀ ofꢀ CHCl3ꢀ (asꢀ aꢀ representativeꢀ poly-halogenatedꢀ
II
4 6
Fig.ꢀ1ꢀCyclicꢀvoltammogramꢀofꢀ2ꢀ(1.0ꢀmM)ꢀinꢀMeCNꢀusingꢀn-Bu NPF ꢀ(0.10ꢀM)ꢀasꢀtheꢀ
-
1
organicꢀ compound)ꢀ withꢀ theꢀ Ni ꢀ complexes.ꢀ Theꢀ modestꢀ electrolyteꢀatꢀ(a)ꢀscanꢀrateꢀ=ꢀ100ꢀmVꢀs ꢀforꢀtheꢀaccessibleꢀsolventꢀwindowꢀ(A,ꢀBꢀandꢀCꢀ
II
I
III
II
catalyticꢀperformancesꢀalludeꢀtoꢀtheꢀneedꢀforꢀmoreꢀstericallyꢀ standꢀforꢀtheꢀNi /Ni ꢀandꢀNi /Ni ꢀredoxꢀcouples,ꢀfollowedꢀbyꢀformationꢀofꢀtheꢀligand-
II
I
basedꢀcationꢀradical,ꢀrespectively);ꢀ(b)ꢀdifferentꢀscanꢀratesꢀforꢀtheꢀNi /Ni ꢀredoxꢀcouple.ꢀ
encumberingꢀ ligandꢀ designsꢀ toꢀ preserveꢀ longer-termꢀ
electrocatalyticꢀactivityꢀbyꢀavoidingꢀreactivityꢀatꢀtheꢀligand.ꢀ
Theꢀarrowsꢀindicateꢀtheꢀdirectionsꢀofꢀtheꢀscans.ꢀ
Tableꢀ1ꢀElectrochemicalꢀdataꢀforꢀtheꢀcomplexesꢀ2ꢀandꢀ3ꢀ(0.10ꢀmM)ꢀinꢀMeCNꢀusingꢀn-
-1 a
4 6
Bu NPF ꢀ(0.10ꢀM)ꢀasꢀtheꢀelectrolyteꢀatꢀaꢀscanꢀrateꢀ=ꢀ100ꢀmVꢀs . ꢀ
Resultsꢀandꢀdiscussion
ꢀ
ox
red
+
II
Complexꢀ
E
p
/ꢀE
p
ꢀ(VꢀvsꢀFc /Fc)ꢀ
Theꢀ preparationꢀ ofꢀ [N(Me)
4 2 2
] [Ni (Me opba)]ꢀ (2)ꢀ isꢀ identicalꢀ toꢀ
previousꢀprocedures,ꢀwithꢀmodificationsꢀtoꢀtheꢀscale,ꢀasꢀshownꢀinꢀ
2ꢀ
-2.38/-2.46ꢀ
-2.34/-2.44ꢀ
-2.33/-2.46ꢀ
-0.21/-0.32ꢀ
0.15/0.09ꢀ
0.15/0.08ꢀ
0.49/0.44ꢀ
0.78/ꢀ–ꢀ
47,ꢀ48,ꢀ54
SchemesꢀS1ꢀandꢀS2ꢀ(ESI).
ꢀWeꢀhaveꢀfullyꢀcharacterizedꢀ2ꢀandꢀ
3aꢀ
3bꢀ
foundꢀ thatꢀ theꢀ spectroscopicꢀ propertiesꢀ matchꢀ thoseꢀ foundꢀ inꢀ aꢀ
0.77/ꢀ–ꢀ
54
previouslyꢀreportedꢀstudy. ꢀInꢀaddition,ꢀweꢀhaveꢀconductedꢀcyclicꢀ
3cꢀ
-2.32/-2.44ꢀ
-2.38/-2.47ꢀ
0.17/0.11ꢀ
0.16/0.09ꢀ
0.77/ꢀ–ꢀ
0.83/ꢀ–ꢀ
3
dꢀ
voltammetryꢀofꢀ2ꢀinꢀacetonitrileꢀ(MeCN,ꢀFig.ꢀ1ꢀandꢀS20ꢀ(ESI))ꢀandꢀ
DMSO,ꢀ usingꢀ n-Bu
4
NPF
6
ꢀ and
ꢀ
KPF
6
ꢀ asꢀ theꢀ supportingꢀ electrolytes,ꢀ
a
ox
red
ꢀ
Ep ꢀ andꢀ Ep ꢀ representꢀ theꢀ oxidationꢀ andꢀ reductionꢀ peakꢀ potentialsꢀ
respectively.ꢀ Theꢀ cyclicꢀ voltammogramsꢀ areꢀ foundꢀ toꢀ beꢀ respectively.ꢀ
comparableꢀ inꢀ bothꢀ solvents.ꢀ Theꢀ electrochemicalꢀ dataꢀ areꢀ
2
ꢀ|ꢀDaltonꢀTrans.,ꢀ2016,ꢀ00,ꢀ1-3ꢀ
Thisꢀjournalꢀisꢀ©ꢀTheꢀRoyalꢀSocietyꢀofꢀChemistryꢀ2016ꢀ
Pleaseꢀdoꢀnotꢀadjustꢀmarginsꢀ

Page 3 of 9
Ple aDs ae lꢀ dt oo nꢀ n To rt aꢀ an d sj ua cs tt ꢀi mo na sr ginsꢀ
DaltonꢀTransactionsꢀ
ꢀARTICLEꢀ
ꢀ
IRꢀ spectroscopyꢀ verifiedꢀ theꢀ alkylationꢀ ofꢀ aꢀ N-mVeietwhAyrltoicxleaOmnildineeꢀ
DOI: 10.1039/C6DT02349E
groupꢀinꢀ2ꢀtoꢀtheꢀimidateꢀesterꢀinꢀeachꢀofꢀtheꢀcomplexesꢀ3a-3d.ꢀTheꢀ
IRꢀspectraꢀofꢀ2ꢀandꢀ3a-3dꢀareꢀpresentedꢀinꢀFig.ꢀ3.ꢀNewꢀvibrationalꢀ
–
1
bandsꢀappearedꢀforꢀ3a-3dꢀaroundꢀ1650ꢀcm ,ꢀwhichꢀwereꢀabsentꢀorꢀ
hiddenꢀ inꢀ theꢀ broadꢀ umbrellaꢀ ofꢀ theꢀ parentꢀ complexꢀ 2ꢀ (Tableꢀ 4).ꢀ
6
4,ꢀ65
Theseꢀbandsꢀcanꢀbeꢀassignedꢀtoꢀtheꢀν(C=N)ꢀstretch,
ꢀinꢀlineꢀwithꢀ
theꢀsingleꢀcrystalꢀX-rayꢀstructures.ꢀInꢀaddition,ꢀtheꢀunreactedꢀν(C=O)ꢀ
frequenciesꢀofꢀ2ꢀwereꢀblue-shiftedꢀafterꢀalkylationꢀ(Tableꢀ4).ꢀSimilarꢀ
II
blue-shiftsꢀwereꢀreportedꢀforꢀtheꢀligandꢀMe
2
opbaꢀafterꢀreplacingꢀNi ꢀ
ꢀ
II
i
Schemeꢀ1ꢀNucleophilicꢀreactionꢀofꢀ2ꢀwithꢀalkylꢀhalidesꢀRXꢀ(Rꢀ=ꢀMe,ꢀEt,ꢀ Pr,ꢀ Bu;ꢀXꢀ=ꢀ
Br,ꢀI).ꢀ
i
withꢀCu ,ꢀdueꢀtoꢀreducedꢀπꢀdelocalizationꢀofꢀtheꢀC=Oꢀbondꢀofꢀtheꢀ
54
oxalylꢀamideꢀfragment. ꢀ
ꢀ
Tableꢀ2ꢀChemicalꢀshiftsꢀforꢀmethoxy,ꢀethoxy,ꢀisopropoxy,ꢀandꢀisobutoxyꢀgroupꢀinꢀtheꢀ
complexesꢀ3a-3d,ꢀrespectively.ꢀ
(a)
(b)
ꢀ
Chemicalꢀshiftꢀ(ppm)ꢀ
Complexꢀ
1
13
O4
O2
O1
HꢀNMRꢀ
CꢀNMRꢀ
O1
C9
N1
N2
N1
N2
3aꢀ
bꢀ
4.35ꢀ(CH
1.32ꢀ(CH
3
)ꢀ
60.4ꢀ(CH
3
)ꢀ
C7
C8
C14
C13
C7
C8
C11
C9
C10
3
3
2
)ꢀ
)ꢀ
16.3ꢀ(CH
69.2ꢀ(CH
3
2
)ꢀ
)ꢀ
Ni1
Ni1
4
.88ꢀ(CH
O3
N4
N3
N4
N3
O4
O3
O2
3
cꢀ
1.32ꢀ(2ꢀxꢀCH
.08ꢀ(CH)ꢀ
0.97ꢀ(2ꢀxꢀCH
.98ꢀ(CH)ꢀ
.64ꢀ(CH )ꢀ
3
)ꢀ
)ꢀ
23.6ꢀ(2ꢀxꢀCH
76.5ꢀ(CH)ꢀ
3
)ꢀ
)ꢀ
6
(c)
(d)
3
dꢀ
3
19.0ꢀ(2ꢀxꢀCH
30.1ꢀ(CH)ꢀ
3
1
4
2
2
78.8ꢀ(CH )ꢀ
O2
O3
O3
O2
N3
N2
N2
N3
ꢀ
C4
C5
C3
C2
C3
C2
C10
C11
C13
C7
inꢀ theꢀ ligandꢀ environmentꢀ afterꢀ O-alkylationꢀ ofꢀ oneꢀ amideꢀ donor.ꢀ
Patently,ꢀ2ꢀisꢀcapableꢀofꢀnucleophilicꢀreactivityꢀevenꢀwithꢀsecondaryꢀ
andꢀ moreꢀ stericallyꢀ hinderedꢀ alkylꢀ iodides,ꢀ althoughꢀ elevatedꢀ
temperaturesꢀareꢀrequired.ꢀ
Ni1
Ni1
O4
N4
N1
O1
N1
N4
O4
O1
(e)
Afterꢀ theꢀ workupꢀ ofꢀ eachꢀ reactionꢀ mixtureꢀ followedꢀ byꢀ
recrystallization,ꢀsingleꢀcrystalsꢀofꢀtheꢀalkylatedꢀderivativesꢀ3ꢀwereꢀ
isolatedꢀ andꢀ examinedꢀ byꢀ X-rayꢀ crystallographicꢀ experiments.ꢀ Asꢀ
illustratedꢀinꢀFig.ꢀ2,ꢀtheꢀalkylꢀgroupsꢀareꢀattachedꢀtoꢀtheꢀoxygenꢀofꢀaꢀ
N-methyloxamideꢀ moietyꢀ inꢀ anꢀ overallꢀ nucleophilicꢀ substitutionꢀ
reactionꢀbyꢀ2ꢀonꢀtheꢀalkylꢀiodides.ꢀFromꢀtheꢀsingle-crystalꢀstructuralꢀ
studies,ꢀtheꢀcomplexesꢀ3aꢀ–ꢀ3dꢀwereꢀobservedꢀtoꢀbeꢀisostructuralꢀ
andꢀ hadꢀ crystallizedꢀ (fromꢀ differentꢀ solventꢀ combinations)ꢀ inꢀ theꢀ
monoclinicꢀcrystalꢀsystem,ꢀalthoughꢀtheꢀcrystalsꢀwereꢀnotꢀisomorphous.ꢀ
Theꢀ salientꢀ crystallographicꢀ experimentalꢀ dataꢀ forꢀ theꢀ complexesꢀ
O
O
N
N
N
N
O
O
Ni
R
i
i
R = Me, Et, Pr or Bu
Fig.ꢀ2ꢀSingleꢀcrystalꢀX-rayꢀstructuresꢀofꢀ(a)ꢀ3a,ꢀ(b)ꢀ3b,ꢀ(c)ꢀ3c,ꢀ(d)ꢀ3d,ꢀandꢀ(e)ꢀnominalꢀ
+
4
ꢀ
resonanceꢀ structuresꢀ ofꢀ theꢀ alkylatedꢀ complexesꢀ 3.ꢀ Allꢀ theꢀ protonsꢀ andꢀ theꢀ NMe
cationꢀhaveꢀbeenꢀomittedꢀforꢀclarity.ꢀ
Tableꢀ3ꢀSelectedꢀbondꢀlengthsꢀ(Å)ꢀandꢀanglesꢀ(°)ꢀforꢀcomplexesꢀ3a-3d.ꢀ
Complexꢀ
Bondꢀlengthꢀ(Å)ꢀ
Bondꢀangleꢀ(°)ꢀ
N3-C8-O3ꢀ
3
a-3dꢀareꢀgivenꢀinꢀtheꢀESI,ꢀandꢀsomeꢀofꢀtheꢀselectedꢀbondꢀlengthsꢀ
andꢀ anglesꢀ areꢀ listedꢀ inꢀ Tableꢀ 3ꢀ andꢀ theꢀ ESI.ꢀ Allꢀ theꢀ Ni-Nꢀ bondꢀ
distancesꢀareꢀsimilarꢀandꢀrangeꢀfromꢀ1.83ꢀÅꢀtoꢀ1.93ꢀÅ.ꢀTheꢀtwoꢀNi-Nꢀ
bondsꢀ correspondingꢀ toꢀ theꢀ phenylenediimineꢀ moietyꢀ areꢀ slightlyꢀ
shorterꢀthanꢀtheꢀotherꢀtwoꢀremainingꢀNi-Nꢀbonds.ꢀCritically,ꢀtheꢀC-Nꢀ
bondꢀlengthsꢀofꢀtheꢀalkylatedꢀN-methyloxamideꢀgroupꢀareꢀfoundꢀtoꢀ
beꢀshortestꢀwhileꢀtheꢀC-Oꢀbondꢀlengthsꢀareꢀtheꢀlongest,ꢀamongꢀtheꢀ
C-NꢀandꢀC=Oꢀbonds,ꢀrespectively.ꢀTheseꢀobservationsꢀareꢀconsistentꢀ
withꢀ theꢀ imidateꢀ esterꢀ tautomericꢀ formꢀ forꢀ theꢀ alkylatedꢀ N-
methyloxamideꢀgroupsꢀ(Fig.ꢀ2e).ꢀSimilarꢀC-NꢀandꢀC-Oꢀbondꢀlengthsꢀ
3
aꢀ
C8-N3ꢀ
1.288(7)ꢀ
1.330(7)ꢀ
119.2(6)ꢀ
115.8(6)ꢀ
125.0(6)ꢀ
118.3(4)ꢀ
117.2(4)ꢀ
124.5(4)ꢀ
C8-O3ꢀ
N3-C8-C7ꢀ
O3-C8-C7ꢀ
N3-C8-O2ꢀ
N3-C8-C7ꢀ
O2-C8-C7ꢀ
3
bꢀ
C8-N3ꢀ
C8-O2ꢀ
ꢀ
1.300(5)ꢀ
1.334(5)ꢀ
ꢀ
3
cꢀ
C11-N4ꢀ
C11-O4ꢀ
ꢀ
1.293(3)ꢀ
1.331(3)ꢀ
ꢀ
N4-C11-O4ꢀ
N4-C11-C10ꢀ
O4-C11-C10ꢀ
119.9(3)ꢀ
116.4(2)ꢀ
123.7(2)ꢀ
II
64-66
haveꢀbeenꢀreportedꢀinꢀNi -imidateꢀcomplexes,
ꢀwhichꢀreinforceꢀ
3
dꢀ
C2-N1ꢀ
C2-O1ꢀ
1.299(5)ꢀ
N1-C2-O1ꢀ
N1-C2-C3ꢀ
O1-C2-C3ꢀ
110.1(8)ꢀ
117.5(3)ꢀ
131.7(9)ꢀ
ourꢀ assignmentꢀ ofꢀ theꢀ complexesꢀ asꢀ theꢀ imidateꢀ esterꢀ tautomerꢀ
afterꢀ alkylation.ꢀ Besidesꢀ this,ꢀ similarꢀ N-Cꢀ bondꢀ lengthsꢀ forꢀ theꢀ
remainingꢀ unreactedꢀ partsꢀ ofꢀ theꢀ ligandꢀ haveꢀ beenꢀ reportedꢀ
1.315(18)ꢀ
II
67-69
previouslyꢀforꢀNi ꢀSchiffꢀbaseꢀcomplexes.
ꢀ
Thisꢀjournalꢀisꢀ©ꢀTheꢀRoyalꢀSocietyꢀofꢀChemistryꢀ2016ꢀ
DaltonꢀTransactions.,ꢀ2016,ꢀ00,ꢀ1-3ꢀ|ꢀ3ꢀ
Pleaseꢀdoꢀnotꢀadjustꢀmarginsꢀ

Ple aDs ae lꢀ dt oo nꢀ n To rt aꢀ an d sj ua cs tt ꢀi mo na sr ginsꢀ
Page 4 of 9
ARTICLEꢀ
DaltonꢀTransactionsꢀ
ꢀ
cationꢀ asꢀ theꢀ soleꢀ organicꢀ partꢀ inꢀ theꢀ solid.ꢀ Theꢀ ESI-VMiewSꢀAdrtiicslpelOanyleindeꢀ
DOI: 10.1039/C6DT02349E
prominentꢀsignalsꢀatꢀm/zꢀ=ꢀ126.83ꢀandꢀ74.22ꢀDaꢀinꢀtheꢀnegativeꢀ(Fig.ꢀ
S33)ꢀ andꢀ positiveꢀ (Fig.ꢀ S34)ꢀ ionꢀ modes,ꢀ respectively.ꢀ Theseꢀ m/zꢀ
–
+
valuesꢀcorrespondedꢀtoꢀI ꢀforꢀtheꢀformerꢀandꢀMe
4
N ꢀforꢀtheꢀlatterꢀ
NI.ꢀꢀ
signals,ꢀandꢀstronglyꢀindicateꢀthatꢀtheꢀmajorꢀby-productꢀwasꢀMe
4
Weꢀhaveꢀalsoꢀexploredꢀtheꢀreactivityꢀofꢀ2ꢀwithꢀorganicꢀbromidesꢀ
suchꢀ asꢀ bromoethaneꢀ andꢀ 2-bromopropane.ꢀ Theꢀ detailedꢀ
proceduresꢀ andꢀ theꢀ relatedꢀ spectralꢀ characterizationsꢀ forꢀ theseꢀ
reactionsꢀareꢀgivenꢀinꢀtheꢀESI.ꢀItꢀisꢀevidentꢀfromꢀFig.ꢀS13ꢀandꢀS14ꢀ
thatꢀ eachꢀ ofꢀ theꢀ substrateꢀ reactedꢀ withꢀ 2ꢀ andꢀ formedꢀ theirꢀ
correspondingꢀalkylatedꢀproducts.ꢀTheꢀchemicalꢀshiftꢀvaluesꢀforꢀtheꢀ
newꢀ productsꢀ wereꢀ foundꢀ toꢀ beꢀ identicalꢀ withꢀ thatꢀ ofꢀ 3bꢀ andꢀ 3c,ꢀ
respectively,ꢀ regardlessꢀ ofꢀ theꢀ useꢀ ofꢀ theꢀ iodoꢀ orꢀ bromoꢀ alkane.ꢀ
1
Besideꢀ HꢀNMRꢀspectroscopy,ꢀtheꢀESI-MSꢀrecordedꢀforꢀtheꢀreactionꢀ
mixtureꢀ showedꢀ peaksꢀ atꢀ m/zꢀ =ꢀ 361.04ꢀ andꢀ 374.85,ꢀ whichꢀ alsoꢀ
–
–
matchedꢀ theꢀ valuesꢀ forꢀ theꢀ monoanionicꢀ [3b] ꢀ andꢀ [3c] ,ꢀ
respectively.ꢀ Notablyꢀ however,ꢀ theꢀ reactionsꢀ ofꢀ 3ꢀ withꢀ theꢀ
Fig.ꢀ3ꢀFT-IRꢀspectraꢀofꢀ2ꢀ(black),ꢀ3aꢀ(red),ꢀ3bꢀ(blue),ꢀ3cꢀ(pink),ꢀandꢀ3dꢀ(green)ꢀinꢀtheꢀ bromoalkanesꢀ wereꢀ slowerꢀ andꢀ gaveꢀ lowerꢀ conversions,ꢀ likelyꢀ
–
1
rangeꢀofꢀ1200ꢀ–ꢀ1800ꢀcm .ꢀ
–
–
becauseꢀBr ꢀisꢀaꢀpoorerꢀleavingꢀgroupꢀthanꢀI .ꢀ
Besideꢀthese,ꢀweꢀhaveꢀfurtherꢀexploredꢀtheꢀreactionꢀofꢀ2ꢀwithꢀ2-
Tableꢀ4ꢀInfraredꢀspectralꢀdataꢀforꢀcomplexesꢀ2ꢀandꢀ3a-3d.ꢀ
Complexꢀ
bromoethanol,ꢀ benzylꢀ bromide,ꢀ andꢀ bromotrichloromethaneꢀ
(
3
BrCCl ).ꢀ Fromꢀ Fig.ꢀ S15,ꢀ weꢀ observedꢀ thatꢀ 2ꢀ reactedꢀ withꢀ 2-
Assignmentꢀ
ν(C=O)ꢀ
bromoethanolꢀtoꢀformꢀatꢀleastꢀoneꢀnewꢀproductꢀ3e,ꢀwhichꢀseemedꢀ
consistentꢀwithꢀaꢀsimilarꢀnucleophilicꢀsubtitutionꢀofꢀtheꢀbromideꢀbyꢀ
theꢀamideꢀofꢀ2.ꢀHowever,ꢀ3eꢀappearedꢀtoꢀbeꢀhydrolyticallyꢀunstableꢀ
2
ꢀ
3aꢀ
3bꢀ
3cꢀ
3dꢀ
1
1
590ꢀ
607ꢀ
ꢀ
1602ꢀ
1629ꢀ
1650ꢀ
1603ꢀ
1629ꢀ
1658ꢀ
1601ꢀ
1626ꢀ
1655ꢀ
1595ꢀ
1623ꢀ
1655ꢀ
o
evenꢀatꢀ0ꢀ C,ꢀandꢀonlyꢀtheꢀdemetallatedꢀligand,ꢀ1,ꢀremainedꢀafterꢀ
ν(C=N)ꢀ
oneꢀweek.ꢀSimilarly,ꢀtheꢀreactionꢀofꢀ2ꢀwithꢀbenzylꢀbromideꢀalsoꢀledꢀ
toꢀanꢀintractableꢀproductꢀmixtureꢀ(Fig.ꢀS17).ꢀConsequently,ꢀweꢀcouldꢀ
notꢀ isolateꢀ theꢀ pureꢀ productꢀ inꢀ eitherꢀ case.ꢀ Interestingly,ꢀ uponꢀ
ꢀ
TheꢀUV-visibleꢀspectraꢀforꢀ2ꢀandꢀ3a-3dꢀwereꢀrecordedꢀinꢀMeCNꢀ
3
mixingꢀ 2ꢀ withꢀ BrCCl ,ꢀ thereꢀ wasꢀ aꢀ distinctꢀ colorꢀ changeꢀ ofꢀ theꢀ
andꢀpresentedꢀinꢀFig.ꢀS31,ꢀandꢀtheꢀλmaxꢀvaluesꢀareꢀsummarizedꢀinꢀ
reactionꢀ mixtureꢀ fromꢀ yellowꢀ toꢀ brown.ꢀ However,ꢀ theꢀ productꢀ
appearedꢀ toꢀ beꢀ paramagnetic,ꢀ sinceꢀ theꢀ signalsꢀ forꢀ 2ꢀ vanishedꢀ
withinꢀ10ꢀminutesꢀwithꢀnoꢀnewꢀpeaksꢀfromꢀ–100ꢀtoꢀ+100ꢀppmꢀ(Fig.ꢀ
S16).ꢀUnfortunately,ꢀmultipleꢀattemptsꢀtoꢀisolateꢀsingleꢀcrystalsꢀthatꢀ
areꢀ suitableꢀ forꢀ X-rayꢀ diffractionꢀ haveꢀ notꢀ beenꢀ successfulꢀ soꢀ far,ꢀ
althoughꢀweꢀproposeꢀthatꢀ2ꢀhasꢀprobablyꢀbeenꢀoxidizedꢀtoꢀformꢀaꢀ
Tableꢀ S1.ꢀ Theꢀ absorptionꢀ peaksꢀ forꢀ 2ꢀ matchedꢀ thoseꢀ reportedꢀ
54
previously. ꢀ Theꢀ higherꢀ energyꢀ electronicꢀ transitionꢀ inꢀ theꢀ UVꢀ
regionꢀatꢀ255ꢀnmꢀcanꢀbeꢀascribedꢀtoꢀintraligandꢀ(IL)ꢀπ–π*ꢀtransitionsꢀ
ofꢀtheꢀphenylenediimineꢀmotif,ꢀwhereasꢀtheꢀabsorptionꢀatꢀ357ꢀnmꢀisꢀ
54
dueꢀ toꢀ metal–to–ligandꢀ chargeꢀ transferꢀ (MLCT)ꢀ transitions. ꢀ
Besidesꢀ these,ꢀ theꢀ broadꢀ shoulderꢀ inꢀ theꢀ rangeꢀ 410-465ꢀ nmꢀ isꢀ
attributedꢀ toꢀ superpositionsꢀ ofꢀ d–dꢀ transitionsꢀ fromꢀ theꢀ filledꢀ dꢀ
brominatedꢀ Ni(III)ꢀ productꢀ (3f).ꢀ Ourꢀ attemptsꢀ toꢀ trapꢀ theꢀ ⦁CCl
3
ꢀ
II
radicalꢀ withꢀ theꢀ helpꢀ ofꢀ EPRꢀ spectroscopyꢀ atꢀ roomꢀ temperatureꢀ
orbitalsꢀtoꢀtheꢀemptyꢀLUMOꢀofꢀtheꢀNi ꢀcomplexꢀinꢀtheꢀsquare-planarꢀ
54
haveꢀalsoꢀbeenꢀunsuccessfulꢀdueꢀtoꢀitsꢀhighꢀreactivity.ꢀBesideꢀthese,ꢀ
geometry. ꢀ However,ꢀ thereꢀ isꢀ aꢀ blue-shiftꢀ forꢀ theseꢀ peaksꢀ afterꢀ
alkylationꢀofꢀ2.ꢀTheꢀIL,ꢀMLCT,ꢀandꢀd–dꢀbandsꢀappearedꢀinꢀtheꢀrangeꢀ
ofꢀ250-252,ꢀ308-310,ꢀandꢀ359-362ꢀnm,ꢀrespectivelyꢀforꢀ3a-3d.ꢀThisꢀ
couldꢀ ariseꢀ fromꢀ theꢀ weakerꢀ π-donor,ꢀ andꢀ conversely,ꢀ moreꢀ
effectiveꢀ π-acceptorꢀ propertiesꢀ ofꢀ theꢀ imidateꢀ esterꢀ tautomericꢀ
form,ꢀ whichꢀ increasesꢀ theꢀ gapꢀ betweenꢀ theꢀ dꢀ orbitalsꢀ amongꢀ
complexesꢀ3a-3d.ꢀ
weꢀwereꢀunableꢀtoꢀobserveꢀC
2 6
Cl ꢀinꢀtheꢀreactionꢀmixtureꢀbyꢀGC-MS.ꢀ
Weꢀhaveꢀalsoꢀattemptedꢀtheꢀreactionꢀofꢀpentafluoropyridineꢀwithꢀ2ꢀ
1
19
inꢀMeCN.ꢀTheꢀ Hꢀandꢀ F{H}ꢀNMRꢀspectraꢀrecordedꢀatꢀdifferentꢀtimeꢀ
intervalsꢀareꢀshownꢀinꢀFig.ꢀS18ꢀandꢀS19,ꢀrespectively.ꢀTheꢀnewꢀpeaksꢀ
inꢀ theꢀ spectraꢀ indicatedꢀ thatꢀ 2ꢀ hadꢀ reactedꢀ withꢀ
pentafluoropyridine,ꢀ althoughꢀ theꢀ massꢀ spectrumꢀ mainlyꢀ showedꢀ
theꢀ presenceꢀ ofꢀ mainlyꢀ 2.ꢀ Consequently,ꢀ weꢀ cannotꢀ conclusivelyꢀ
identifyꢀtheꢀproduct.ꢀ
Theꢀby-productꢀinꢀtheꢀreactionꢀofꢀ2ꢀwithꢀoneꢀofꢀtheꢀalkylꢀiodidesꢀ
wasꢀconclusivelyꢀidentifiedꢀbyꢀNMRꢀspectroscopyꢀandꢀelectrosprayꢀ
ionization-massꢀspectrometryꢀ(ESI-MS).ꢀInꢀaꢀrepresentativeꢀreaction,ꢀ
afterꢀisolationꢀofꢀtheꢀproductꢀ3aꢀfromꢀtheꢀreactionꢀbetweenꢀ2ꢀandꢀ
methylꢀiodide,ꢀtheꢀsolidꢀresidueꢀremainingꢀinꢀtheꢀreactionꢀflaskꢀwasꢀ
Cyclicꢀ voltammetryꢀ experimentsꢀ ofꢀ 3a-3dꢀ wereꢀ performedꢀ toꢀ
examineꢀ theꢀ redoxꢀ propertiesꢀ ofꢀ 2ꢀ afterꢀ alkylation.ꢀ Theꢀ CVsꢀ wereꢀ
6 4 6
conductedꢀ inꢀ DMSOꢀ andꢀ MeCNꢀ usingꢀ KPF ꢀ andꢀ n-Bu NPF ,ꢀ
1
respectively,ꢀasꢀtheꢀsupportingꢀelectrolyteꢀunderꢀanꢀatmosphereꢀofꢀ
argonꢀ(Ar).ꢀTheꢀCVsꢀforꢀtheꢀcomplexesꢀareꢀshownꢀinꢀFig.ꢀ4ꢀandꢀFig.ꢀ
S21-S24ꢀ(ESI)ꢀandꢀtheꢀelectrochemicalꢀdataꢀareꢀsummarizedꢀinꢀTableꢀ
1.ꢀTheꢀcyclicꢀvoltammogramꢀofꢀ3aꢀconsistsꢀofꢀaꢀreversibleꢀwaveꢀatꢀ
washedꢀwithꢀhexaneꢀandꢀdriedꢀinꢀvacuo.ꢀTheꢀ HꢀNMRꢀspectrumꢀandꢀ
1
ESI-MSꢀofꢀtheꢀdriedꢀresidueꢀareꢀshownꢀinꢀFig.ꢀS32ꢀ-ꢀS34ꢀ(ESI).ꢀTheꢀ Hꢀ
NMRꢀspectrumꢀshowedꢀaꢀsingletꢀatꢀδꢀ=ꢀ3.09,ꢀwhichꢀcorrespondsꢀtoꢀ
+
Me
4
N ꢀ cation.ꢀ Apartꢀ fromꢀ this,ꢀ thereꢀ wereꢀ noꢀ additionalꢀ peaksꢀ inꢀ
ox
p
+
E1/2ꢀofꢀ0.12ꢀVꢀ(Fig.ꢀ4a)ꢀandꢀaꢀquasi-reversibleꢀwaveꢀatꢀE ꢀvalueꢀofꢀ
4
theꢀ rangeꢀ ofꢀ δꢀ =ꢀ -1ꢀ toꢀ 22.ꢀ Thisꢀ confirmedꢀ theꢀ presenceꢀ ofꢀ Me N ꢀ
III
II
0
.78ꢀVꢀ(Fig.ꢀS21),ꢀwhichꢀcorrespondsꢀtoꢀtheꢀNi /Ni ꢀandꢀligand-basedꢀ
4
ꢀ|ꢀDaltonꢀTrans.,ꢀ2016,ꢀ00,ꢀ1-3ꢀ
Thisꢀjournalꢀisꢀ©ꢀTheꢀRoyalꢀSocietyꢀofꢀChemistryꢀ2016ꢀ
Pleaseꢀdoꢀnotꢀadjustꢀmarginsꢀ

Page 5 of 9
Ple aDs ae lꢀ dt oo nꢀ n To rt aꢀ an d sj ua cs tt ꢀi mo na sr ginsꢀ
DaltonꢀTransactionsꢀ
ꢀARTICLEꢀ
cationꢀradicalꢀredoxꢀcouples,ꢀrespectively.ꢀTheseꢀvaluesꢀareꢀshiftedꢀ 4).ꢀTheꢀrelativeꢀoxidativeꢀstabilitiesꢀofꢀ2ꢀandꢀ3a-3d,ꢀasꢀsuggestedꢀbyꢀ
View Article Online
DOI: 10.1039/C6DT02349E
III
II
anodicallyꢀ byꢀ aboutꢀ 390ꢀ andꢀ 310ꢀ mVꢀ comparedꢀ toꢀ theirꢀ theirꢀreversibleꢀNi /Ni ꢀoxidationꢀwaves,ꢀattestꢀtoꢀtheꢀrobustnessꢀofꢀ
correspondingꢀ potentialsꢀ inꢀ 2.ꢀ Thisꢀ differentꢀ redoxꢀ behaviorꢀ likelyꢀ Me opbaꢀasꢀaꢀligand,ꢀandꢀcorroborateꢀtheꢀpreviousꢀreportsꢀonꢀtheirꢀ
arisesꢀsinceꢀ3aꢀisꢀmonoanionic,ꢀwhereasꢀ2ꢀisꢀaꢀmoreꢀelectron-richꢀ applicationsꢀinꢀoxidationꢀcatalysis,ꢀincludingꢀevenꢀwaterꢀoxidation.
2
47-
54
dianionicꢀ–ateꢀcomplex.ꢀBesideꢀthese,ꢀtheꢀcyclicꢀvoltammogramꢀofꢀ
aꢀconsistsꢀofꢀaꢀquasi-reversibleꢀwaveꢀatꢀE1/2ꢀofꢀ–2.39ꢀVꢀdueꢀtoꢀtheꢀ
ꢀ
3
Withꢀtheseꢀcomplexesꢀinꢀhand,ꢀweꢀexploredꢀtheꢀelectrocatalyticꢀ
reductionꢀofꢀCHCl ꢀinꢀtheꢀabsenceꢀandꢀpresenceꢀofꢀproticꢀsolvents.ꢀ
Inꢀ preliminaryꢀ experiments,ꢀ CVsꢀ wereꢀ carriedꢀ outꢀ withꢀ CHCl ꢀ andꢀ
isopropylꢀalcoholꢀ(IPA)ꢀinꢀtheꢀpresenceꢀorꢀabsenceꢀofꢀtheꢀcatalystꢀinꢀ
DMSOꢀusingꢀKPF ꢀ(0.10ꢀM)ꢀasꢀtheꢀsupportingꢀelectrolyteꢀ(Fig.ꢀS25-
S28).ꢀFromꢀtheꢀCVsꢀitꢀwasꢀfoundꢀthatꢀtheꢀsolventꢀreductionꢀcurrentꢀ
II
I
Ni /Ni ꢀredoxꢀcouple.ꢀTheꢀpositionꢀofꢀthisꢀredoxꢀcoupleꢀsurprisinglyꢀ
3
appearedꢀtoꢀbeꢀsimilarꢀtoꢀthatꢀofꢀ2.ꢀTheꢀpeak-to-peakꢀseparationꢀforꢀ
3
III
II
II
I
theꢀNi /Ni ꢀandꢀNi /Ni ꢀcouplesꢀinꢀ3aꢀhaveꢀbeenꢀfoundꢀtoꢀbeꢀ60ꢀmVꢀ
andꢀ 100ꢀ mV,ꢀ respectively,ꢀ comparedꢀ toꢀ almostꢀ identicalꢀ peak-to-
peakꢀseparationsꢀofꢀ90ꢀmVꢀinꢀtheꢀcorrespondingꢀredoxꢀcouplesꢀofꢀ2.ꢀꢀ
6
II
I
III
II
Similarꢀtoꢀ3a,ꢀtheꢀcomplexesꢀ3b-3dꢀshowedꢀNi /Ni ,ꢀNi /Ni ,ꢀandꢀ increasedꢀonlyꢀslightlyꢀinꢀtheꢀpresenceꢀofꢀ2ꢀ(Fig.ꢀS25).ꢀInterestingly,ꢀ
ligand-basedꢀcationꢀradicalꢀredoxꢀcouplesꢀatꢀaroundꢀ-2.40,ꢀ0.13ꢀandꢀ withꢀ theꢀ alkylatedꢀ complexesꢀ 3,ꢀ theꢀ onsetꢀ potentialꢀ wasꢀ shiftedꢀ
III
II
0
.79ꢀ V,ꢀ respectively,ꢀ inꢀ theirꢀ cyclicꢀ voltammograms.ꢀ Theꢀ Ni /Ni ꢀ positivelyꢀ(Fig.ꢀS26-S28),ꢀprobablyꢀdueꢀtoꢀtheꢀmonoanionicꢀchargesꢀ
II
I
redoxꢀcouplesꢀareꢀfoundꢀtoꢀbeꢀreversibleꢀwhereasꢀtheꢀNi /Ni ꢀandꢀ ofꢀ 3ꢀ asꢀ opposedꢀ toꢀ theꢀ dianionicꢀ 2.ꢀ Withꢀ theseꢀ encouragingꢀ
ligand-basedꢀcationꢀradicalꢀredoxꢀcouplesꢀareꢀquasi-reversibleꢀ(Fig.ꢀ
observations,ꢀweꢀconductedꢀcontrolledꢀpotentialꢀelectrolysisꢀ(CPE)ꢀ
experimentsꢀforꢀtheꢀreductionꢀofꢀCHCl .ꢀTheꢀresultsꢀareꢀsummarizedꢀ
3
1
inꢀTableꢀ5.ꢀTheꢀconversionsꢀwereꢀcalculatedꢀonꢀtheꢀbasisꢀofꢀ HꢀNMRꢀ
spectraꢀrecordedꢀforꢀaliquotsꢀtakenꢀoutꢀfromꢀtheꢀreactionꢀmixtureꢀ
beforeꢀ andꢀ afterꢀ electrolysis.ꢀ Benzeneꢀ wasꢀ usedꢀ asꢀ anꢀ internalꢀ
standardꢀforꢀeachꢀCPEꢀexperiment.ꢀꢀ
3
Atꢀ theꢀ beginning,ꢀ electrocatalyticꢀ reductionꢀ ofꢀ CHCl ꢀ wasꢀ
conductedꢀ inꢀ theꢀ absenceꢀ ofꢀ proticꢀ solventsꢀ byꢀ usingꢀ 2ꢀ asꢀ theꢀ
+
catalystꢀatꢀ-2.5ꢀVꢀforꢀ30ꢀminꢀ(vsꢀFc /Fc,ꢀTableꢀ5,ꢀentryꢀ2).ꢀOnlyꢀ3%ꢀ
conversionꢀ wasꢀ detected.ꢀ Inꢀ aꢀ separateꢀ experiment,ꢀ theꢀ reactionꢀ
wasꢀrepeatedꢀinꢀtheꢀpresenceꢀofꢀIPAꢀ(2ꢀequivalentsꢀrelativeꢀtoꢀtheꢀ
3
CHCl ꢀsubstrate)ꢀasꢀtheꢀprotonꢀsourceꢀandꢀtheꢀconversionꢀwasꢀfoundꢀ
toꢀincreaseꢀbyꢀthree-foldꢀ(Tableꢀ5,ꢀentryꢀ3).ꢀWeꢀalsoꢀexploredꢀtheꢀ
reactivityꢀofꢀtheꢀcomplexesꢀinꢀtheꢀpresenceꢀofꢀwaterꢀorꢀmethanolꢀasꢀ
theꢀprotonꢀsources,ꢀbutꢀtheꢀconversionꢀdidꢀnotꢀincreaseꢀ(Tableꢀ5,ꢀ
entriesꢀ 4ꢀ andꢀ 5).ꢀ Notably,ꢀ inꢀ theꢀ controlꢀ experimentꢀ conductedꢀ
underꢀsimilarꢀreactionꢀconditionsꢀusingꢀIPAꢀasꢀtheꢀprotonꢀsourceꢀbutꢀ
inꢀ theꢀ absenceꢀ ofꢀ 3,ꢀ onlyꢀ 2%ꢀ conversionꢀ ofꢀ CHCl
Tableꢀ 5,ꢀ entryꢀ 1).ꢀ Thisꢀ indicatedꢀ thatꢀ theꢀ complexꢀ playedꢀ anꢀ
importantꢀroleꢀinꢀtheꢀelectrolysis.ꢀꢀ
3
ꢀ wasꢀ observedꢀ
(
WeꢀhaveꢀfurtherꢀcarriedꢀoutꢀtheꢀCPEꢀmeasurementsꢀusingꢀ3a-3dꢀ
asꢀ theꢀ catalystsꢀ inꢀ theꢀ presenceꢀ ofꢀ IPAꢀ andꢀ foundꢀ thatꢀ theꢀ
conversionsꢀrangeꢀfromꢀ9ꢀtoꢀ11%,ꢀcorrespondingꢀtoꢀTONsꢀofꢀ4.7ꢀtoꢀ
5
.6ꢀ(Tableꢀ5,ꢀentriesꢀ6-9).ꢀUnderꢀotherwiseꢀidenticalꢀCPEꢀconditions,ꢀ
increasingꢀtheꢀreactionꢀtimeꢀwithꢀorꢀwithoutꢀ2ꢀorꢀ3ꢀasꢀtheꢀcatalystꢀ
upꢀtoꢀ2ꢀhꢀdidꢀnotꢀincreaseꢀtheꢀconversion.ꢀꢀWeꢀalsoꢀidentifiedꢀtraceꢀ
1
amountsꢀofꢀdichloromethaneꢀasꢀtheꢀproductꢀinꢀtheꢀ HꢀNMRꢀspectraꢀ
(
Fig.ꢀ S30).ꢀ Thoughꢀ theꢀ complexesꢀ 2ꢀ andꢀ 3ꢀ showedꢀ onlyꢀ modestꢀ
conversionsꢀ inꢀ comparisonꢀ toꢀ previousꢀ reportsꢀ onꢀ theꢀ
3
2,ꢀ
electrocatalyticꢀreductionꢀofꢀorganicꢀhalidesꢀbyꢀmetalꢀcomplexes,
70-75
ꢀ
furtherꢀworkꢀtoꢀimproveꢀtheꢀconversionꢀandꢀalsoꢀidentifyꢀotherꢀ
products,ꢀsuchꢀasꢀH
2
,ꢀareꢀunderꢀwayꢀinꢀourꢀteam.ꢀ
ꢀ
ꢀ
III
Fig.ꢀ4ꢀCyclicꢀvoltammogramsꢀforꢀ3a-3dꢀatꢀdifferentꢀscanꢀrates.ꢀ(a)ꢀNi /Ni ꢀredoxꢀ
II
II
I
coupleꢀ andꢀ (b)ꢀ Ni /Ni ꢀ redoxꢀ coupleꢀ forꢀ 3aꢀ (withꢀ 0.10ꢀ Mꢀ KPF
6
ꢀ inꢀ DMSO);ꢀ (c)ꢀ
Ni /Ni ꢀredoxꢀcoupleꢀandꢀ(d)ꢀNi /Ni ꢀredoxꢀcoupleꢀforꢀ3bꢀ(withꢀ0.10ꢀMꢀKPF ꢀinꢀ
DMSO);ꢀ(e)ꢀNi /Ni ꢀredoxꢀcoupleꢀandꢀ(f)ꢀNi /Ni ꢀredoxꢀcoupleꢀforꢀ3cꢀ(withꢀ0.10ꢀMꢀ
III
II
II
I
6
III
II
II
I
III
II
II
I
KPF
6
ꢀinꢀDMSO);ꢀ(g)ꢀNi /Ni ꢀredoxꢀcoupleꢀandꢀ(h)ꢀNi /Ni ꢀredoxꢀcoupleꢀforꢀ3dꢀ(withꢀ
0
.10ꢀMꢀn-Bu
4
NPF ꢀinꢀMeCN).ꢀTheꢀarrowsꢀindicateꢀtheꢀdirectionsꢀofꢀtheꢀscans.ꢀ
6
Thisꢀjournalꢀisꢀ©ꢀTheꢀRoyalꢀSocietyꢀofꢀChemistryꢀ2016ꢀ
DaltonꢀTransactions.,ꢀ2016,ꢀ00,ꢀ1-3ꢀ|ꢀ5ꢀ
Pleaseꢀdoꢀnotꢀadjustꢀmarginsꢀ

Ple aDs ae lꢀ dt oo nꢀ n To rt aꢀ an d sj ua cs tt ꢀi mo na sr ginsꢀ
Page 6 of 9
ARTICLEꢀ
DaltonꢀTransactionsꢀ
redꢀsolutionꢀtoꢀprecipitateꢀaꢀyellowꢀtoꢀorangeꢀsolid.ꢀ
a
Tableꢀ5ꢀElectrocatalyticꢀreductionꢀofꢀCHCl
3
ꢀbyꢀtheꢀcomplexesꢀ2ꢀandꢀ3. ꢀ
Theꢀsrtolidꢀwnlianesꢀ
View A icle O
DOI: 10.1039/C6DT02349E
filteredꢀoffꢀandꢀdriedꢀinꢀvacuoꢀtoꢀyieldꢀpureꢀ2ꢀ(0.383ꢀg,ꢀ79.9%).ꢀTheꢀ
productꢀidentityꢀhasꢀbeenꢀconfirmedꢀbyꢀNMRꢀspectroscopyꢀandꢀHR-
Entryꢀ
Complexꢀ
Conversionꢀ(%)ꢀ
TONꢀ
1
b
ESI-MS.ꢀ HꢀNMRꢀ(MeOH-d ,ꢀ300ꢀMHz):ꢀδꢀ=ꢀ2.60ꢀ(s,ꢀ6ꢀH),ꢀ3.17ꢀ(s,ꢀ24ꢀ
4
1
ꢀ
noneꢀ
2ꢀ
2ꢀ
3ꢀ
ꢀ
c
H),ꢀ 6.68ꢀ (dd,ꢀ Jꢀ =ꢀ 3.3,ꢀ 6.0ꢀ Hz,ꢀ 2ꢀ H),ꢀ 8.03ꢀ (dd,ꢀJꢀ =ꢀ 3.3,ꢀ 6.0ꢀ Hz,ꢀ 2ꢀ H).ꢀ
2
ꢀ
1.6ꢀ
5.0ꢀ
1
3
1
C{ H}ꢀNMRꢀ(MeOD-d
44.7,ꢀ166.0,ꢀ172.1.ꢀHRMSꢀ(ESI–,ꢀm/z)ꢀcalculatedꢀforꢀC12
4
,ꢀ126ꢀMHz):ꢀδꢀ=ꢀ34.2,ꢀ56.1ꢀ(t),ꢀ120.7,ꢀ123.4,ꢀ
3
ꢀ
2ꢀ
10ꢀ
d
1
H
11
N
4
NiO
4
ꢀ
4
5
ꢀ
ꢀ
2ꢀ
2ꢀ
6ꢀ
6ꢀ
9ꢀ
3.2ꢀ
3.0ꢀ
4.7ꢀ
–
e
[Mꢀ+ꢀH] ꢀm/zꢀ=ꢀ333.0134,ꢀfoundꢀ333.0137.ꢀ
6
ꢀ
3aꢀ
Reactionꢀofꢀ2ꢀwithꢀiodomethaneꢀtoꢀformꢀ3aꢀ(remainingꢀexamplesꢀ
inꢀESI):ꢀ
7
8
9
ꢀ
ꢀ
ꢀ
3bꢀ
3cꢀ
3dꢀ
11ꢀ
9ꢀ
5.6ꢀ
4.7ꢀ
5.6ꢀ
Aꢀ2ꢀMꢀsolutionꢀofꢀiodomethaneꢀ(226.0ꢀµL,ꢀ0.45ꢀmmol)ꢀinꢀtert-
butylꢀ methylꢀ etherꢀ wasꢀ addedꢀ toꢀ aꢀ solutionꢀ ofꢀ 2ꢀ (0.050ꢀ g,ꢀ 0.090ꢀ
11ꢀ
a
ꢀ
AllꢀCPEꢀexperimentsꢀwereꢀconductedꢀinꢀDMSOꢀ(15ꢀmL)ꢀusingꢀKPF
theꢀsupportingꢀelectrolyteꢀatꢀ-2.5ꢀVꢀforꢀ30ꢀminꢀ(50ꢀmMꢀbenzene,ꢀ50ꢀmMꢀCHCl
00ꢀmMꢀiso-propylꢀalcohol,ꢀandꢀ1.0ꢀmMꢀcomplexꢀunderꢀargon),ꢀunlessꢀotherwiseꢀ
6
ꢀ(0.10ꢀM)ꢀasꢀ mmol)ꢀinꢀ50ꢀmLꢀMeCNꢀunderꢀN ꢀinꢀaꢀSchlenkꢀtube.ꢀTheꢀtubeꢀwasꢀ
2
3
,ꢀ
sealed,ꢀheatedꢀtoꢀ35ꢀºC,ꢀandꢀstirredꢀforꢀ72ꢀhꢀduringꢀwhichꢀtheꢀcolorꢀ
changedꢀ fromꢀ yellowꢀ toꢀ red.ꢀ Afterꢀ theꢀ reaction,ꢀ theꢀ MeCNꢀ wasꢀ
removedꢀunderꢀreduceꢀpressure,ꢀdriedꢀinꢀvacuo,ꢀandꢀwashedꢀwithꢀ
hexaneꢀ(5ꢀmLꢀxꢀ3).ꢀTheꢀredꢀcomplexꢀwasꢀextractedꢀwithꢀacetoneꢀ(5ꢀ
mL)ꢀ twiceꢀ andꢀ theꢀ combinedꢀ acetoneꢀ extractsꢀ wereꢀ driedꢀ underꢀ
reducedꢀpressure.ꢀTheꢀcrudeꢀsolidꢀredꢀproductꢀwasꢀre-dissolvedꢀinꢀ
MeCNꢀ(5ꢀmL)ꢀandꢀdiethylꢀetherꢀ(~5ꢀmL)ꢀwasꢀaddedꢀdropwiseꢀuntilꢀ
someꢀ yellowꢀ colorꢀ precipitateꢀ appeared.ꢀ Theꢀ precipitateꢀ wasꢀ
1
b
c
d
e
indicated.ꢀ ꢀNoꢀcatalystꢀadded.ꢀ ꢀNoꢀproticꢀsolvent.ꢀ ꢀWaterꢀasꢀprotonꢀsource.ꢀ ꢀ
Methanolꢀasꢀprotonꢀsource.ꢀ
Experimentalꢀ
Generalꢀinformationꢀ
Allꢀ theꢀ newꢀ Ni(II)ꢀ complexes,ꢀ 3a-dꢀ wereꢀ synthesizedꢀ byꢀ usingꢀ allowedꢀ toꢀ deposit,ꢀ beforeꢀ beingꢀ filteredꢀ off.ꢀ Theꢀ redꢀ filtrateꢀ wasꢀ
standardꢀ Schlenkꢀ lineꢀ techniquesꢀ underꢀ N
,ꢀ unlessꢀ otherwiseꢀ driedꢀinꢀvacuoꢀtoꢀprovideꢀpureꢀ3aꢀinꢀhighꢀyieldsꢀ(0.032ꢀg,ꢀ88.9%).ꢀ
indicated.ꢀ Theꢀ chemicals,ꢀ includingꢀ anhydrousꢀ dimethylꢀ sulfoxideꢀ Diffusionꢀ ofꢀ anhydrousꢀ diethylꢀ etherꢀ intoꢀ aꢀ MeCNꢀ solutionꢀ ofꢀ theꢀ
DMSO),ꢀwereꢀpurchasedꢀfromꢀSigma-Aldrich,ꢀAlfa-Aesar,ꢀandꢀTokyoꢀ complexꢀgaveꢀredꢀcrystalsꢀthatꢀwereꢀsuitableꢀforꢀsingleꢀcrystalꢀX-rayꢀ
2
(
1
ChemicalꢀIndustryꢀ(TCI),ꢀandꢀwereꢀusedꢀasꢀreceived.ꢀTheꢀdeuteratedꢀ structuralꢀanalysis.ꢀ HꢀNMRꢀ(CD
3
CN,ꢀ300ꢀMHz):ꢀδꢀ=ꢀ2.50ꢀ(s,ꢀ3ꢀH),ꢀ2.78ꢀ
solventsꢀwereꢀpurchasedꢀfromꢀCambridgeꢀIsotopeꢀLaboratoriesꢀandꢀ (s,ꢀ3ꢀH),ꢀ3.09ꢀ(s,ꢀ12ꢀH),ꢀ4.35ꢀ(s,ꢀ3ꢀH),ꢀ6.59-6.72ꢀ(m,ꢀ2ꢀH),ꢀ7.97ꢀ(dd,ꢀJꢀ=ꢀ
1
3
1
wereꢀ usedꢀ asꢀ received.ꢀ Anhydrousꢀ acetonitrileꢀ (MeCN)ꢀ wasꢀ 1.5,ꢀ7.8ꢀHz,ꢀ1ꢀH),ꢀ8.07ꢀ(dd,ꢀJꢀ=ꢀ1.5,ꢀ7.8ꢀHz,ꢀ1ꢀH).ꢀ C{ H}ꢀNMRꢀ(CD
3
CN,ꢀ
obtainedꢀ fromꢀ aꢀ PUREꢀ SOLVꢀ MD-5ꢀ solventꢀ purificationꢀ systemꢀ 126ꢀMHz):ꢀδꢀ=ꢀ32.8,ꢀ36.0,ꢀ56.2ꢀ(t),ꢀ60.4,ꢀ119.6,ꢀ119.9,ꢀ121.6,ꢀ123.6,ꢀ
(
InnovativeꢀTechnology,ꢀInc.).ꢀ
142.8,ꢀ 146.0,ꢀ 160.1,ꢀ 163.4,ꢀ 165.8,ꢀ 171.3.ꢀ HRMSꢀ (ESI–,ꢀ m/z)ꢀ
–
calculatedꢀforꢀC13
ElementalꢀanalysesꢀforꢀC17
6.59%;ꢀfound:ꢀC,ꢀ48.35;ꢀH,ꢀ6.04;ꢀN,ꢀ16.23%.ꢀ
H
13
N
4
NiO
4
ꢀ[M] ꢀm/zꢀ=ꢀ347.0290,ꢀfoundꢀ347.0292.ꢀ
TheꢀNMRꢀspectraꢀwereꢀacquiredꢀatꢀroomꢀtemperatureꢀonꢀeitherꢀ
H
25
N
5
NiO ꢀcalculated:ꢀC,ꢀ48.37;ꢀH,ꢀ5.97;ꢀN,ꢀ
4
aꢀBrukerꢀAVANCEꢀ300ꢀMHzꢀorꢀ500ꢀMHzꢀspectrometer.ꢀTheꢀchemicalꢀ
1
shiftꢀ(δ)ꢀvaluesꢀareꢀreportedꢀinꢀpartsꢀperꢀmillionꢀ(ppm)ꢀrelativeꢀtoꢀ
1
residualꢀsolventꢀpeaksꢀ(CDCl
1
3
1
ꢀ=ꢀ7.26ꢀppmꢀforꢀ Hꢀandꢀ77.2ꢀppmꢀforꢀ Electrochemistry:ꢀCyclicꢀvoltammetryꢀ
3
13
3 4
C;ꢀCD CNꢀ=ꢀ1.94ꢀppmꢀforꢀ Hꢀandꢀ118.3ꢀppmꢀforꢀ C;ꢀMeOD-d ꢀ=ꢀ
.31ꢀppmꢀforꢀ Hꢀandꢀ49.2ꢀppmꢀforꢀ C;ꢀDMSO-d ꢀ=ꢀ2.50ꢀppmꢀforꢀ Hꢀ
6
Theꢀcyclicꢀvoltammetryꢀexperimentsꢀwereꢀcarriedꢀoutꢀbyꢀusingꢀaꢀ
BiologicꢀSP-300ꢀpotentiostatꢀinꢀanhydrousꢀDMSOꢀorꢀMeCNꢀwithꢀ0.10ꢀ
1
13
1
3
13
andꢀ39.52ꢀppmꢀforꢀ C).ꢀCrystallographicꢀdataꢀwereꢀrecordedꢀonꢀaꢀ
Brukerꢀ X8ꢀ CCDꢀ diffractometer.ꢀ Theꢀ structuresꢀ wereꢀ solvedꢀ andꢀ
refinedꢀusingꢀtheꢀBrukerꢀSHELXTLꢀsoftwareꢀpackage.ꢀHigh-resolutionꢀ
electrosprayꢀ ionizationꢀ massꢀ spectraꢀ (HR-ESIMS)ꢀ wereꢀ obtainedꢀ
usingꢀaꢀWatersꢀQ-TofꢀPremierꢀmassꢀspectrometer.ꢀInfraredꢀspectraꢀ
ofꢀtheꢀsamplesꢀwereꢀrecordedꢀasꢀKBrꢀpelletsꢀusingꢀaꢀBrukerꢀVERTEXꢀ
6 4
Mꢀ KPF ꢀ orꢀ n-Bu NPF6ꢀ asꢀ theꢀ supportingꢀ electrolyte.ꢀ Aꢀ standardꢀ
three-electrodeꢀelectrochemicalꢀcellꢀwasꢀused,ꢀconsistingꢀofꢀaꢀglassyꢀ
carbonꢀworkingꢀelectrodeꢀ(3ꢀmmꢀinꢀdiameterꢀfromꢀBAS),ꢀaꢀPtꢀwireꢀasꢀ
theꢀ counterꢀ electrode,ꢀ andꢀ anꢀ Ag/AgClꢀ electrodeꢀ asꢀ aꢀ referenceꢀ
electrodeꢀ orꢀ anotherꢀ Ptꢀ wireꢀ asꢀ aꢀ pseudo-referenceꢀ electrode.ꢀ
Ferroceneꢀ wasꢀ usedꢀ asꢀ anꢀ internalꢀ referenceꢀ whenꢀ aꢀ Ptꢀ wireꢀ wasꢀ
usedꢀasꢀtheꢀpseudo-referenceꢀelectrodeꢀandꢀallꢀtheꢀpotentialsꢀhaveꢀ
8
0ꢀspectrophotometer.ꢀ
Preparationꢀofꢀcompoundꢀ(Me
Complexꢀ(Me N) [Ni(Me opba)]ꢀ(2)ꢀwasꢀpreparedꢀbyꢀusingꢀtheꢀ
procedureꢀ previouslyꢀ reported. ꢀ Inꢀ aꢀ typicalꢀ experiment,ꢀ aꢀ 25%ꢀ
aqueousꢀsolutionꢀofꢀ(Me N)OHꢀ(1.31ꢀmL,ꢀ3.60ꢀmmol)ꢀwasꢀaddedꢀtoꢀ
+
4
N)
2
[Ni(Me
2
opba)]ꢀ(2)ꢀ
beenꢀreportedꢀvsꢀtheꢀferrocenium/ferroceneꢀ(Fc /Fc)ꢀredoxꢀcouple.ꢀ
Theꢀglassyꢀcarbonꢀelectrodeꢀwasꢀpolishedꢀbetweenꢀeachꢀrunꢀonꢀaꢀ
polishingꢀpadꢀusingꢀaꢀsuspensionꢀofꢀ0.05ꢀµmꢀaluminaꢀandꢀdistilledꢀ
water.ꢀThisꢀwasꢀfollowedꢀbyꢀsonicationꢀinꢀdistilledꢀwaterꢀforꢀ10ꢀmin,ꢀ
beforeꢀ theꢀ electrodeꢀ wasꢀ air-dried.ꢀ Beforeꢀ eachꢀ electrolysis,ꢀ theꢀ
solutionsꢀwereꢀbubbledꢀwithꢀargonꢀforꢀ15ꢀmin.ꢀ
4
2
2
54
4
aꢀsuspensionꢀofꢀ1ꢀ(0.200ꢀg,ꢀ0.72ꢀmmol)ꢀinꢀmethanolꢀ(15ꢀmL).ꢀTheꢀ
mixtureꢀ wasꢀ heatedꢀ atꢀ 50ꢀ ºCꢀ andꢀ stirredꢀ tillꢀ itꢀ becameꢀ clear.ꢀ Theꢀ
solutionꢀ wasꢀ cooledꢀ toꢀ roomꢀ temperatureꢀ andꢀ aꢀ Ni(ClO
0.26ꢀ g,ꢀ 0.72ꢀ mmol)ꢀ solutionꢀ inꢀ methanolꢀ (10ꢀ mL)ꢀ wasꢀ addedꢀ
dropwiseꢀ underꢀ stirring.ꢀ Theꢀ reactionꢀ mixtureꢀ wasꢀ filteredꢀ toꢀ
removeꢀtheꢀprecipitatedꢀ(Me N)ClO .ꢀSubsequently,ꢀtheꢀvolumeꢀofꢀ
4
)
2
.6H
2
Oꢀ Controlledꢀpotentialꢀelectrolysisꢀ(CPE)ꢀ
(
Theꢀ CPEꢀ experimentsꢀ wereꢀ performedꢀ inꢀ aꢀ sealedꢀ glassꢀ cellꢀ
usingꢀaꢀglassyꢀcarbonꢀrodꢀ(10ꢀmmꢀdiameterꢀxꢀ15ꢀmmꢀlength)ꢀasꢀtheꢀ
4
4
workingꢀ electrode,ꢀ aꢀ Ptꢀ wireꢀ asꢀ theꢀ counterꢀ electrode,ꢀ andꢀ anꢀ
Ag/AgClꢀelectrodeꢀasꢀtheꢀreferenceꢀelectrodeꢀorꢀanotherꢀPtꢀwireꢀasꢀ
aꢀpseudo-referenceꢀelectrode.ꢀBeforeꢀeachꢀexperiment,ꢀtheꢀglassyꢀ
theꢀredꢀsolutionꢀwasꢀreducedꢀtoꢀone-thirdꢀunderꢀreducedꢀpressure.ꢀ
Diethylꢀetherꢀandꢀacetoneꢀwereꢀsuccessivelyꢀaddedꢀtoꢀtheꢀfinalꢀdeepꢀ
6
ꢀ|ꢀDaltonꢀTrans.,ꢀ2016,ꢀ00,ꢀ1-3ꢀ
Thisꢀjournalꢀisꢀ©ꢀTheꢀRoyalꢀSocietyꢀofꢀChemistryꢀ2016ꢀ
Pleaseꢀdoꢀnotꢀadjustꢀmarginsꢀ

Page 7 of 9
Ple aDs ae lꢀ dt oo nꢀ n To rt aꢀ an d sj ua cs tt ꢀi mo na sr ginsꢀ
DaltonꢀTransactionsꢀ
ꢀARTICLEꢀ
9
1
1
.ꢀ
C.ꢀA.ꢀMartinez-HuitleꢀandꢀS.ꢀFerro,ꢀChem.ꢀSoc.ꢀRev.,ꢀ2006,ꢀ35,ꢀ1324-1340.ꢀ
View Article Online
carbonꢀrodꢀwasꢀpolishedꢀandꢀwashedꢀasꢀdescribedꢀabove.ꢀAꢀtypicalꢀ
electrolysisꢀwasꢀcarriedꢀoutꢀunderꢀargonꢀinꢀDMSOꢀ(15ꢀmL)ꢀwithꢀKPF
0.ꢀ S.ꢀK.ꢀKhetanꢀandꢀT.ꢀJ.ꢀCollins,ꢀChem.ꢀRev.,ꢀ2007,ꢀ107,ꢀ2319-2364.ꢀ
1.ꢀ T.ꢀJ.ꢀCollins,ꢀAcc.ꢀChem.ꢀRes.,ꢀ2002,ꢀ35,ꢀ782-790.ꢀ
DOI: 10.1039/C6DT02349E
6
ꢀ
(
0.10ꢀ M)ꢀ asꢀ theꢀ supportingꢀ electrolyte,ꢀ benzeneꢀ (50ꢀ mM)ꢀ asꢀ anꢀ 12.ꢀ S.ꢀ Kundu,ꢀ A.ꢀ Chanda,ꢀ S.ꢀ K.ꢀ Khetan,ꢀ A.ꢀ D.ꢀ Ryabovꢀ andꢀ T.ꢀ J.ꢀ Collins,ꢀEnviron.ꢀ Sci.ꢀ
1
Technol.,ꢀ2013,ꢀ47,ꢀ5319-5326.ꢀ
3
internalꢀstandardꢀforꢀ HꢀNMRꢀspectroscopy,ꢀCHCl ꢀ(50ꢀmM)ꢀasꢀtheꢀ
1
1
1
3.ꢀ J.ꢀM.ꢀCarter,ꢀM.ꢀJ.ꢀMoran,ꢀJ.ꢀS.ꢀZogorskiꢀandꢀC.ꢀV.ꢀPrice,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ
2012,ꢀ46,ꢀ8189-8197.ꢀ
4.ꢀ B.ꢀRao,ꢀN.ꢀEstrada,ꢀS.ꢀMcGee,ꢀJ.ꢀMangold,ꢀB.ꢀH.ꢀGuꢀandꢀW.ꢀA.ꢀJackson,ꢀEnviron.ꢀSci.ꢀ
Technol.,ꢀ2012,ꢀ46,ꢀ11635-11643.ꢀ
substrate,ꢀandꢀtheꢀmetalꢀcomplexꢀ(1.0ꢀmM)ꢀasꢀtheꢀcatalyst.ꢀBeforeꢀ
eachꢀ CPEꢀ experiment,ꢀ argonꢀ wasꢀ bubbledꢀ throughꢀ theꢀ reactionꢀ
mixtureꢀ forꢀ 15ꢀ min,ꢀ whichꢀ wasꢀ followedꢀ byꢀ linearꢀ sweepꢀ
voltammetryꢀ(LSV)ꢀexperimentsꢀtoꢀconfirmꢀthatꢀtheꢀcomplexesꢀwereꢀ
pure.ꢀBeforeꢀandꢀafterꢀelectrolysis,ꢀaliquotsꢀwereꢀremovedꢀfromꢀtheꢀ
5.ꢀ Z.ꢀL.ꢀFan,ꢀJ.ꢀY.ꢀHu,ꢀW.ꢀAnꢀandꢀM.ꢀYang,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ2013,ꢀ47,ꢀ10841-
1
0850.ꢀ
1
1
6.ꢀ Y.ꢀPanꢀandꢀX.ꢀR.ꢀZhang,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ2013,ꢀ47,ꢀ1265-1273.ꢀ
7.ꢀ D.ꢀM.ꢀCwiertny,ꢀS.ꢀA.ꢀSnyder,ꢀD.ꢀSchlenkꢀandꢀE.ꢀP.ꢀKolodziej,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ
2014,ꢀ48,ꢀ11737-11745.ꢀ
1
cellꢀ withꢀ aꢀ gas-tightꢀ syringeꢀ forꢀ Hꢀ NMRꢀ spectroscopicꢀ
1
1
2
8.ꢀ L.ꢀDeng,ꢀC.ꢀH.ꢀHuangꢀandꢀY.ꢀL.ꢀWang,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ2014,ꢀ48,ꢀ2697-2705.ꢀ
9.ꢀ K.ꢀD.ꢀLin,ꢀC.ꢀYanꢀandꢀJ.ꢀGan,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ2014,ꢀ48,ꢀ263-271.ꢀ
0.ꢀ S.ꢀY.ꢀPang,ꢀJ.ꢀJiang,ꢀY.ꢀGao,ꢀY.ꢀZhou,ꢀX.ꢀL.ꢀHuangfu,ꢀY.ꢀZ.ꢀLiuꢀandꢀJ.ꢀMa,ꢀEnviron.ꢀSci.ꢀ
Technol.,ꢀ2014,ꢀ48,ꢀ615-623.ꢀ
measurements.ꢀ
2
2
1.ꢀ M.ꢀT.ꢀYangꢀandꢀX.ꢀR.ꢀZhang,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ2014,ꢀ48,ꢀ11846-11852.ꢀ
2.ꢀ H.ꢀY.ꢀZhai,ꢀX.ꢀR.ꢀZhang,ꢀX.ꢀH.ꢀZhu,ꢀJ.ꢀQ.ꢀLiuꢀandꢀM.ꢀJi,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ2014,ꢀ
Conclusionsꢀ
4
8,ꢀ2579-2588.ꢀ
Weꢀ haveꢀ shownꢀ thatꢀ theꢀ –ateꢀ complexꢀ 2,ꢀ bearingꢀ theꢀ
tetraanionicꢀ ligandꢀ 1,ꢀ isꢀ capableꢀ ofꢀ nucleophilicꢀ substitutionꢀ
reactionsꢀ withꢀ alkylꢀ iodidesꢀ andꢀ bromidesꢀ underꢀ slightlyꢀ elevatedꢀ
temperatures.ꢀ Theꢀ productsꢀ 3ꢀ areꢀ alkylatedꢀ atꢀ theꢀ N-
2
2
3.ꢀ M.ꢀVenier,ꢀA.ꢀSalamovaꢀandꢀR.ꢀA.ꢀHites,ꢀAcc.ꢀChem.ꢀRes.,ꢀ2015,ꢀ48,ꢀ1853-1861.ꢀ
4.ꢀ X.ꢀW.ꢀWang,ꢀX.ꢀF.ꢀHu,ꢀH.ꢀZhang,ꢀF.ꢀChangꢀandꢀY.ꢀM.ꢀLuo,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ
2015,ꢀ49,ꢀ6683-6690.ꢀ
5.ꢀ H.ꢀX.ꢀZhao,ꢀJ.ꢀQ.ꢀJiang,ꢀY.ꢀL.ꢀWang,ꢀH.ꢀJ.ꢀLehmler,ꢀG.ꢀR.ꢀBuettner,ꢀX.ꢀQuanꢀandꢀJ.ꢀW.ꢀ
Ghen,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ2015,ꢀ49,ꢀ14120-14128.ꢀ
2
methyloxamideꢀoxygenꢀandꢀhaveꢀbeenꢀstructurallyꢀcharacterizedꢀbyꢀ 26.ꢀ Q.ꢀZhao,ꢀH.ꢀM.ꢀZhao,ꢀX.ꢀQuan,ꢀX.ꢀHeꢀandꢀS.ꢀChen,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ2015,ꢀ49,ꢀ
092-9099.ꢀ
9
X-rayꢀ crystallography.ꢀ Furthermore,ꢀ 2ꢀ andꢀ 3ꢀ functionꢀ asꢀ
electrocatalystsꢀinꢀtheꢀreductionꢀofꢀCHCl ,ꢀalbeitꢀwithꢀlowꢀTONs.ꢀOurꢀ
2
7.ꢀ U.ꢀAli,ꢀJ.ꢀH.ꢀSyed,ꢀR.ꢀN.ꢀMalik,ꢀA.ꢀKatsoyiannis,ꢀJ.ꢀLi,ꢀG.ꢀZhangꢀandꢀK.ꢀC.ꢀJones,ꢀSci.ꢀ
TotalꢀEnviron.,ꢀ2014,ꢀ476–477,ꢀ705-717.ꢀ
3
resultsꢀdemonstrateꢀtheꢀfeasibilityꢀofꢀaꢀcatalyticꢀreductiveꢀapproachꢀ 28.ꢀ G.ꢀWang,ꢀC.ꢀFeng,ꢀC.ꢀKang,ꢀB.ꢀZhang,ꢀN.ꢀChenꢀandꢀX.ꢀZhang,ꢀJ.ꢀEnviron.ꢀEng.,ꢀ2016,ꢀ
42,ꢀ04015066.ꢀ
9.ꢀ G.ꢀChen,ꢀZ.ꢀWangꢀandꢀD.ꢀXia,ꢀElectrochem.ꢀCommun.,ꢀ2004,ꢀ6,ꢀ268-272.ꢀ
readilyꢀ preparedꢀ –ateꢀ complexesꢀ composedꢀ ofꢀ Earth-abundantꢀ 30.ꢀ H.ꢀCheng,ꢀK.ꢀScottꢀandꢀP.ꢀA.ꢀChristensen,ꢀJ.ꢀElectroanal.ꢀChem.,ꢀ2004,ꢀ566,ꢀ131-
1
toꢀ chemicallyꢀ transformꢀ halogenatedꢀ organicꢀ pollutantsꢀ byꢀ usingꢀ
2
1
38.ꢀ
elements.ꢀ Nevertheless,ꢀ theꢀ catalyticꢀ activityꢀ ofꢀ theꢀ Niꢀ
electrocatalystsꢀareꢀlikelyꢀtoꢀbeꢀhamperedꢀbyꢀirreversibleꢀalkylationꢀ
ofꢀtheꢀligandꢀinsteadꢀofꢀreversibleꢀelectronꢀtransfersꢀfromꢀtheꢀmetalꢀ
centerꢀ toꢀ theꢀ substrate.ꢀ Ongoingꢀ studiesꢀ inꢀ ourꢀ teamꢀ includeꢀ theꢀ
3
3
3
1.ꢀ C.ꢀCui,ꢀX.ꢀQuan,ꢀH.ꢀYuꢀandꢀY.ꢀHan,ꢀAppliedꢀCatal.ꢀBꢀEnviron.,ꢀ2008,ꢀ80,ꢀ122-128.ꢀ
2.ꢀ Z.ꢀSun,ꢀH.ꢀGe,ꢀX.ꢀHuꢀandꢀY.ꢀPeng,ꢀChem.ꢀEng.ꢀTechnol.,ꢀ2009,ꢀ32,ꢀ134-139.ꢀ
3.ꢀ D.ꢀSadowsky,ꢀK.ꢀMcNeillꢀandꢀC.ꢀJ.ꢀCramer,ꢀEnviron.ꢀSci.ꢀTechnol.,ꢀ2014,ꢀ48,ꢀ10904-
1
0911.ꢀ
3
4.ꢀ C.ꢀDingꢀandꢀJ.ꢀZ.ꢀHe,ꢀMicrob.ꢀBiotechnol.,ꢀ2012,ꢀ5,ꢀ347-367.ꢀ
developmentꢀofꢀnovelꢀNiꢀ–ateꢀmolecularꢀsystemsꢀthatꢀareꢀsupportedꢀ 35.ꢀ S.ꢀGazi,ꢀW.ꢀK.ꢀH.ꢀNg,ꢀR.ꢀGanguly,ꢀA.ꢀM.ꢀP.ꢀMoeljadi,ꢀH.ꢀHiraoꢀandꢀH.ꢀS.ꢀSoo,ꢀChem.ꢀ
Sci.,ꢀ2015,ꢀ6,ꢀ7130-7142.ꢀ
6.ꢀ S.ꢀK.ꢀMuduli,ꢀS.ꢀWang,ꢀS.ꢀChen,ꢀC.ꢀF.ꢀNg,ꢀC.ꢀH.ꢀA.ꢀHuan,ꢀT.ꢀC.ꢀSumꢀandꢀH.ꢀS.ꢀSoo,ꢀ
BeilsteinꢀJ.ꢀNanotechnol.,ꢀ2014,ꢀ5,ꢀ517-523.ꢀ
7.ꢀ J.ꢀW.ꢀKee,ꢀY.ꢀY.ꢀNg,ꢀS.ꢀA.ꢀKulkarni,ꢀS.ꢀK.ꢀMuduli,ꢀK.ꢀXu,ꢀR.ꢀGanguly,ꢀY.ꢀLu,ꢀH.ꢀHiraoꢀ
andꢀH.ꢀS.ꢀSoo,ꢀInorg.ꢀChem.ꢀFront.,ꢀ2016,ꢀ3,ꢀ651-662.ꢀ
8.ꢀ H.ꢀShao,ꢀS.ꢀK.ꢀMuduli,ꢀP.ꢀD.ꢀTranꢀandꢀH.ꢀS.ꢀSoo,ꢀChem.ꢀCommun.,ꢀ2016,ꢀ52,ꢀ2948-
byꢀ moreꢀ stericallyꢀ bulkyꢀ ligands,ꢀ whichꢀ exploitꢀ theꢀ Niꢀ nucleusꢀ
3
3
3
3
instead,ꢀasꢀtheꢀsiteꢀforꢀnucleophilicꢀactivity.ꢀ
Acknowledgementsꢀ
2
951.ꢀ
9.ꢀ J.ꢀWang,ꢀR.ꢀGanguly,ꢀY.ꢀLi,ꢀJ.ꢀDiaz,ꢀH.ꢀS.ꢀSooꢀandꢀF.ꢀGarcia,ꢀDaltonꢀTrans.,ꢀ2016,ꢀ45,ꢀ
941-7946.ꢀ
H.S.S.ꢀ isꢀ supportedꢀ byꢀ aꢀ NTUꢀ start-upꢀ grantꢀ (M4081012),ꢀ theꢀ
7
Nanyangꢀ Assistantꢀ Professorshipꢀ (M4081154),ꢀ andꢀ anꢀ MOEꢀ Tierꢀ 1ꢀ 40.ꢀ H.ꢀShimakoshiꢀandꢀY.ꢀHisaeda,ꢀChemPlusChem,ꢀ2014,ꢀ79,ꢀ1250-1253.ꢀ
4
4
1.ꢀ S.ꢀO.ꢀObare,ꢀT.ꢀItoꢀandꢀG.ꢀJ.ꢀMeyer,ꢀJ.ꢀAm.ꢀChem.ꢀSoc.,ꢀ2006,ꢀ128,ꢀ712-713.ꢀ
2.ꢀ J.ꢀR.ꢀStromberg,ꢀJ.ꢀD.ꢀWnuk,ꢀR.ꢀA.ꢀF.ꢀPinlacꢀandꢀG.ꢀJ.ꢀMeyer,ꢀNanoꢀLett.,ꢀ2006,ꢀ6,ꢀ
1284-1286.ꢀ
3.ꢀ R.ꢀJ.ꢀKuhler,ꢀG.ꢀA.ꢀSanto,ꢀT.ꢀR.ꢀCaudill,ꢀE.ꢀA.ꢀBettertonꢀandꢀR.ꢀG.ꢀArnold,ꢀEnviron.ꢀ
Sci.ꢀTechnol.,ꢀ1993,ꢀ27,ꢀ2104-2111.ꢀ
grantꢀ(M4011144).ꢀTheꢀauthorsꢀacknowledgeꢀtheꢀsupportꢀfromꢀtheꢀ
SolarꢀFuelsꢀLaboratoryꢀatꢀNTUꢀandꢀtheꢀSingapore-BerkeleyꢀResearchꢀ
Initiativeꢀ forꢀ Sustainableꢀ Energyꢀ (SinBeRISE)ꢀ CREATEꢀ Programme.ꢀ
Thisꢀ researchꢀ programꢀ isꢀ fundedꢀ byꢀ theꢀ Nationalꢀ Researchꢀ
4
4
4.ꢀ M.ꢀGoez,ꢀC.ꢀKerzigꢀandꢀR.ꢀNaumann,ꢀAngew.ꢀChem.ꢀInt.ꢀEd.,ꢀ2014,ꢀ53,ꢀ9914-9916.ꢀ
Foundationꢀ (NRF),ꢀ Primeꢀ Minister’sꢀ Office,ꢀ Singaporeꢀ underꢀ itsꢀ 45.ꢀ E.ꢀT.ꢀChukovskaya,ꢀM.ꢀA.ꢀRozhkova,ꢀN.ꢀA.ꢀKuzminaꢀandꢀR.ꢀK.ꢀFreidlina,ꢀBull.ꢀAcad.ꢀ
Sci.ꢀUSSRꢀChem.ꢀSci.,ꢀ1982,ꢀ31,ꢀ321-325.ꢀ
6.ꢀ D.ꢀA.ꢀWhite,ꢀSynth.ꢀReact.ꢀInorg.ꢀMet.-Org.ꢀChem.,ꢀ1977,ꢀ7,ꢀ433-443.ꢀ
Campusꢀ forꢀ Researchꢀ Excellenceꢀ andꢀ Technologicalꢀ Enterpriseꢀ
4
(
CREATE).ꢀꢀ
47.ꢀ R.ꢀRuiz,ꢀC.ꢀSurville-Barland,ꢀA.ꢀAukauloo,ꢀE.ꢀAnxolabehere-Mallart,ꢀY.ꢀJournaux,ꢀJ.ꢀ
CanoꢀandꢀM.ꢀC.ꢀMunoz,ꢀJ.ꢀChem.ꢀSoc.ꢀDaltonꢀTrans.,ꢀ1997,ꢀ745-751.ꢀ
4
8.ꢀ I.ꢀFernandez,ꢀJ.ꢀR.ꢀPedro,ꢀA.ꢀL.ꢀRosello,ꢀR.ꢀRuiz,ꢀX.ꢀOttenwaelderꢀandꢀY.ꢀJournaux,ꢀ
TetrahedronꢀLett.,ꢀ1998,ꢀ39,ꢀ2869-2872.ꢀ
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DaltonꢀTransactions.,ꢀ2016,ꢀ00,ꢀ1-3ꢀ|ꢀ7ꢀ
Pleaseꢀdoꢀnotꢀadjustꢀmarginsꢀ

Ple aDs ae lꢀ dt oo nꢀ n To rt aꢀ an d sj ua cs tt ꢀi mo na sr ginsꢀ
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ꢀ|ꢀDaltonꢀTrans.,ꢀ2016,ꢀ00,ꢀ1-3ꢀ
Thisꢀjournalꢀisꢀ©ꢀTheꢀRoyalꢀSocietyꢀofꢀChemistryꢀ2016ꢀ
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Dalton Transactions
View Article Online
DOI: 10.1039/C6DT02349E
Table of contents graphic
Nickel(II) –ate complexes supported by o-phenylenebis(N-methyloxamide) reacted
nucleophilically with alkyl halides to form new imidate tautomers that have been
characterized by X-ray crystallography and FT-IR spectroscopy, and utilized for
electroreduction of chloroform.