Download Density functional calculations show noncovalent interactions

Densityfunctionalcalculations
shownoncovalentinteractions
drivingelectrocatalysis
KlemensNoga1,3,PiotrP.Romańczyk2,Mariusz Radoń3,StefanS.Kurek2
1
AcademicComputerCenter CYFRONET,ul.Nawojki 11,30-950Kraków,Poland
2
MolecularElectrochemistryGroup,FacultyofChemicalEngineeringandTechnology,
CracowUniversityofTechnology,ul.Warszawska 24,31-155Kraków,Poland
3
FacultyofChemistry,Jagiellonian University,ul.Ingardena 3,30-060Kraków,Poland
klemens.noga@cyfronet.pl,piotrom@chemia.pk.edu.pl
Scientificinterests
• Electrontransfermechanismbetweenredoxcentresin
mixed-valencemolybdenumandtungstenscorpionates
involvedinelectrocatalysis
• Dissociativeelectrontransfer(DET)processesin
dehalogenationoforganichalides
• Roleofnoncovalentinteractionsinelectrocatalysis andDET
processes
• Computationalestimationofreductionandoxidation
potentialsoftransitionmetalcomplexesandorganic
compounds
MoandWscorpionate alkoxides
{MoII(NO)(TpMe2)}(OCH3)2
Reversibleredoxpotentialfine
tunedbyalkoxy ligandRO-
• Redoxpotentialof{MII/I(NO)(TpMe2)−Oalk}0/•− (M=MoorW)well
reproducedbyDFT:B3LYP/LACV3P+/IEF-PCM:
• {Mo−OMe}0/•− - calculated:1.80V,measured:1.84V
• {W−OMe}0/•−- calculated:2.45V,measured:2.40V
• Strongmetal-metalinteractions(uptoΔredE1/21440mV)inmixedvalencecompoundswithtwo{MoII–0(NO+)(TpMe2)}2+,1+,0 cores
Electrocatalysis ofofCHCl3 dehalogenation
by{MoI(NO)(TpMe2)(Oalkoxy)}•−
Autocatalytic
process
ΔEred,CHCl3
~1V
ReductionofCHCl3by Hold-ramp-stepexperiment Inhibitionofreactionby
{MoI(NO)(TpMe2)(Oalkoxy)}•− provingstabilityofcatalyst
alkene
• CHCl3 - fastautocatalyticprocess
• CCl4 andC2Cl4 donotreactinthoseconditions,C2HCl5 andC2HCl3 typicalelectrocatalysis
Roleof{MoII/I(NO)(TpMe2)(Oalkoxy)}•− in
electrocatalysis - adducts
DFT-D(COSMO/B3LYP-D3/def2-TZVPP)geometriesof
{MoII/I(NO)(TpMe2)}(OCH3)2adductswithCHCl3
• Moscorpionates formweaklybondedadductswithCHCl3 through
C−H···Oalkoxy hydrogenbondanddispersiveinteractions
• AfterreductionofMocentre∆Ebind increases
Roleof{MoII/I(NO)(TpMe2)(Oalkoxy)}•− in
electrocatalysis - dehalogenation
DFT-D(COSMO/B3LYP-D3/def2-TZVPP)geometriesof
(a){MoI(NO)(TpMe2)}(OCH3)2•−···HCCl3adductwithelongatedC-Clbond(upto2.2Å)inCHCl3
(b){MoII(NO)(TpMe2)}(OCH3)2···HCCl2• adductafterDET
• Weaklybonded{MoI(NO)(TpMe2)}(OCH3)2•−···HCCl3adductfacilitates
electrontransfertochloroformcoupledwithC-Clbondcleavage
Roleof{WII/I(NO)(TpMe2)(Oalkoxy)}•− inC2HCl5
andC2HCl4•dehalogenation
DFT-D(COSMO/B3LYP-D3/def2-TZVPP)geometriesof
(a){WI(NO)(TpMe2)}(OCH3)2•−···HC2Cl5adduct
(b){WII(NO)(TpMe2)}(OCH3)2···HC2Cl4• adductafterDET
• Weaklybonded{WI(NO)(TpMe2)}(OCH3)2•−···HC2Cl5 adductalsofacilitates
electrontransfertopentachloroethane coupledwithC-Clbondcleavage
Thermodynamical stabilityofadducts
Adduct
{MoII−Oalk}0···HCCl3
{MoI−Oalk}•−···HCCl3
{MoII−Oalk}0···HCCl2•
{MoI−Oalk}•−···HC2Cl5
{MoI−Oalk}•−···HC2Cl3
{MoI−Oalk}•−···H2CCl2
{WI−Oalk}•−···HC2Cl5
{WII−Oalk}···HC2Cl4•
{WI−Oalk}•−···HC2Cl4•
{WI−Oalk}•−···HC2Cl3
{WI−Oalk}•−···H2CCl2
∆Ebind
−44.4
−52.3
−37.2
−53.6
−43.1
−37.7
−54.8
−46.4
−56.1
−44.4
−41.0
∆Gbind
0.8
−6,7
6.3
−2.9
1.3
3.8
−5.0
1.7
−5.4
0.4
1.7
inkJ·mol−1 inCH2Cl2 solvent,BSSEcorrected
• {MoI−Oalk}•−···HCCl3 and{WI−Oalk}•−···HC2Cl5stabilisationfacilitatesET
• Lowerstabilityof{MoII−Oalk}0···HCCl2•and{WII−Oalk}···HC2Cl4•enables
radicaldissociationandtriggersanothercatalyticloop
MolecularcatalysisofCHCl3 andC2HCl3 reduction
triggeredbyMo/Walkoxy scorpionates
• CHCl3dehalogenation- twocatalyticloops,withautocatalyticreaction:
2CHCl3 +CCl2•− +3e− →CH2Cl2 +2CCl2•− +2Cl−
• ForC2HCl3 evenmorecathodicWII/I redoxpotentialnotsufficienttoclose
secondorganicloop
Redoxpotentialsofcompoundsinvolved
inC2HCl5 reduction
Species
E0calc(DFT-D)
{WII−OMe}/{WI−OMe}•−
−2.45
{WIII−OMe}•+/{WII−OMe}
+0.68
C2HCl5/C2HCl4• +Cl−
−0.66
C2HCl4•/C2HCl3 +Cl−
+0.93
C2HCl3/cis-C2HCl2• +Cl−
−1.66
cis-C2HCl2•/cis-C2HCl2−
−0.42
cis-C2H2Cl2/cis-C2H2Cl• +Cl−
−1.97
cis-C2H2Cl•/C2H2 +Cl−
+0.99
C2Cl4/C2Cl4•−
−2.32 (−2.14)
C2Cl4/C2Cl3• +Cl−
−1.57
C2Cl3•/C2Cl3−
−0.24
C2HCl/C2H•···Cl−
−2.12
C2HCl/C2H• +Cl−
−2.72
C2HCl/C2H• +Cl−
−2.72
E0calc(CC)
–
–
−1.27(−1.01)
+0.80
−2.12(−1.86)
−0.48
−2.36(−2.10)
+0.91(+1.18)
−2.66(−2.48)
−2.09(−1.82)
−0.24
−2.55(−2.32)
−2.94(−2.68)
−2.94(−2.68)
E0exp
−2,40
+0.63
(−0.98)
(−1.86)
(−2.09)
(−2.11)
(−1.73)
inVvsFc,obtainedinCH2Cl2 solvent(orDMF)
• SignificantdifferencesbetweenDFT-DandCCresultsonlyinthecaseof
dissociativereduction(duetoerrorsinestimationofC-ClbondstrengthinDFT)
Inhibitionofcatalysis
DFT-D(COSMO/B3LYP-D3/def2-TZVPP)geometriesof
(a)alcohol adduct,(b)alkeneadduct
• AlcoholsformstrongerhydrogenbondthanCHCl3 andblockthebindingsite
• Alkenesand DMFarebondedsignificantlyweakerthanCHCl3
• whenaddedingreatexcess
• inhibitionoccurs bytrappingoftransientCHCl2•radicalbyalkeneor:CCl2byDMF
Roleofnoncovalentinteractionsin
electrocatalycis
ComparisonofDFT-D(sharp,Clatomsyellow)andDFT(diffused,Clatomsgreen)
(a){MoII−Oalk}··HCCl3, (b){MoI−Oalk}•−···HCCl3,(c){MoI−Oalk} 0···HCCl2•
• Significantdifferencesinadductsgeometries,especiallyin{MoI−Oalk}
0···HCCl •,wherehydrogenbondisweakerandhasdispersivecharacter
2
• Noncovalentinteractionsarecrucialforstabilisationofadductswith
weakhydrogenbond
Roleofnoncovalentinteractionsin
electrocatalysis
Adduct
{MoII−Oalk}0···HCCl3
{MoI−Oalk}•−···HCCl3
{MoII−Oalk}•−···HCCl2•
{MoI−Oalk}•−···HOCH3
{MoI−Oalk}•−···HC(=O)N(CH3)2a
{WI−Oalk}•−···H2C=CHCH3
DFT
4.2
−4.2
2.1
−22.2
10.5
12.6
DFT//DFT-D3
−32.2
−42.7
−23.8
−52.3
−22.6
−11.3
DFT-D3 Opt
−44.4
−52.3
−37.2
−56.1
−30.1
−22.6
∆Gbind inkJ·mol−1 inCH2Cl2 solvent(a inDMF),BSSEcorrected
• Noncovalentinteractionsarecrucialforstabilisationofadductswith
weakhydrogenbond
• Even{MoI−Oalk}•−···HOCH3 adductwithstrongH-bondshows
stabilisationeffectfromdispersiveinteractions
• GeometryoptimizationusingDFT-D3stronglyrecommended
Softwareremarksandcomputationaldetails
• Gaussian03andGaussian09
• usedforDFTgeometryoptimizationsandredoxpotentialscalculations
• widespectrumofsolvationmethods
• Turbomole 6.xand7.x
• usedforDFT-D3geometryoptimizations
• veryfastingeometryoptimizationsandBSSEestimations
• onlynumericalfrequenciescalculationswhenCOSMOmodelisused
• embarrassinglyparallelbutconsumebigamountofresources(upto120cores
forweek)
• Molpro 2012and2015
• usedforparallelCCSD(T)calculations
• canconsumegreatamountofresources(upto200coresforweeks)dueto
scalingfactorofO(N7)
Outcome
• Rationalizedmechanismofelectrocatalytic dehalogenationof
polychloroalkanes byMoandWscorpionate alkoxides anditsinhibition
• combinedactionofC−H···Oalk bondingandCl···πpyrazolyl dispersiveinteractionsmay
facilitateintramolecularelectrontransfer
• Shownthatdispersioninteractionscouldbecrucialforstabilisationof
weaklybondedadducts
• DFT-Dhastobeusedinsuchcasestoyieldreasonableresults
• Establishedcomputationalprotocolforcalculationofredoxpotentials
forinvestigatedMo/Walkoxides andfororganicchlorideswiththe
accuracyofupto0.05V
• ComputationalresourceshavebeenprovidedbyACCCyfronet AGH
whichispartofPLGrid Infrastructure
Publications
• P.P.Romańczyk,M.Radoń,K.Noga,S.S.Kurek,Autocatalyticcathodic
dehalogenationtriggeredbydissociativeelectrontransferthrougha
C−H···Ohydrogenbond,Phys.Chem.Chem.Phys. 15(2013)17522.
• P.P.Romańczyk,K.Noga,M.Radoń,G.Rotko,S.S.Kurek,Ontheroleof
noncovalentinteractionsinelectrocatalysis.Twocasesofmediated
reductivedehalogenation,Electrochim.Acta,110(2013)619.
• P.P.Romańczyk,G.Rotko,K.Noga,M.Radoń,G.Andryianau,S.S.Kurek,
TheeffectofC−H···ObondingandCl···πinteractionsinelectrocatalytic
dehalogenationofC2chloridescontaininganacidichydrogen,
Electrochim.Acta 140(2014)497.