Lanthanides and actinides

110 Pages·2013·16.66 MB·English

by  Frank T. Edelmann

CoordinationChemistryReviews257 (2013) 1122–1231

ContentslistsavailableatSciVerseScienceDirect

Coordination Chemistry Reviews

journal homepage: www.elsevier.com/locate/ccr

Review
Lanthanides and actinides: Annual survey of their organometallic chemistry

covering the year 2011

FrankT.Edelmann∗

ChemischesInstitutderOtto-von-Guericke-UniversitätMagdeburg,D-39106Magdeburg,Germany

Contents
1. Introduction..........................................................................................................................................1123

2. Lanthanides..........................................................................................................................................1123

2.1. Lanthanidehydrocarbyls.....................................................................................................................1123

2.1.1. Homolepticcompounds............................................................................................................1123

2.1.2. Heterolepticcompounds...........................................................................................................1123

2.2. Lanthanidealkenylandalkynylcompounds.................................................................................................1139

2.3. Lanthanideallyls.............................................................................................................................1140

2.4. Lanthanidecyclopentadienylcomplexes....................................................................................................1140

2.4.1. Cp2Ln compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1140
2.4.2. CpLnX2compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1142
2.4.3. Cp2LnX compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1153
2.4.4. Cp3Ln and Cp3LnL compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1156
2.4.5. Pentamethylcyclopentadienylcompounds........................................................................................1158

2.4.6. Pentalenyl,indenylandfluorenylcompounds.....................................................................................1164

2.5. Organolanthanidecomplexeswithheteroatomfive-memberedringligands..............................................................1166

2.6. Lanthanidearenecomplexes.................................................................................................................1169

2.7. Lanthanidecyclooctatetraenylcomplexes...................................................................................................1175

2.8. Lanthanidemetallofullerenes................................................................................................................1176

2.9. Heterobimetallicorganolanthanidecomplexes..............................................................................................1180

2.10. Organolanthanidecatalysis.................................................................................................................1186

2.10.1. Organolanthanide-catalyzedpolymerizationreactions..........................................................................1186

2.10.2. Organolanthanide-catalyzedhydrosilylation,hydroaminationandhydrophosphinationreactions............................1196

2.10.3. Otherorganolanthanide-catalyzedreactions.....................................................................................1198

2.11. Organolanthanidesinorganicsynthesis....................................................................................................1201

2.12. Organolanthanidesinmaterialsscience....................................................................................................1201

3. Actinides.............................................................................................................................................1203

3.1. Actinidehydrocarbyls........................................................................................................................1203

3.2. Actinidecyclopentadienylcompounds......................................................................................................1215

3.2.1. Cp3An, CpAnX3, Cp2AnX2and Cp3AnX compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1215
3.2.2. Pentamethylcyclopentadienylactinide(IV)-,(V)-,and(VI)-compounds..........................................................1218

3.3. Actinidearenecomplexes....................................................................................................................1220

3.4. Actinidecyclooctatetraenylcomplexes......................................................................................................1222

3.5. Organoactinidesincatalysis..................................................................................................................1227

Acknowledgements..................................................................................................................................1229

References...........................................................................................................................................1229

a r t i c l e i n f o a b s t r a c t

Articlehistory: This review summarizes the progress in organo-f-element chemistry during the year 2011. A con-
Receiv ed3December2012 tinui ngtren dinorganola ntha niderese arc hisastrongemp hasisonap plicatio nso forga nolan tha nide
AAcvcaeilpatbelde 1o n7 lDineec exmxxbe r 2012 comple xes in h om ogeneous catalys is and, to a le ss er exte nt, materia ls s cience. Rough ly 24% of all relevant
∗
Tel.:[phone];fax:[phone].

E-mailaddress:[email protected]

0010-8545/$–seefrontmatter© 2013 Elsevier B.V. All rights reserved.

http://dx.doi.org/10.1016/j.ccr.2012.12.010
F.T.Edelmann/CoordinationChemistryReviews257 (2013) 1122–1231 1123

Keywords: paperspublishedin2011wereintheareaoforganoactinidechemistry,whichcontinuestoproduce

Lanthanides excitingresults.Quiteremarkableisasteadyincreaseinresearchactivitiesfocussedonlanthanideand
Actinides actinide carbene comp lexes.
Cyclopentadienylcomplexes

Cyclooctatetraenylcomplexes
Organometallicche mistry © 2013 Elsevier B.V. All rights reserved.

1. Introduction were assigned to the oxidative addition product methylene lan-

thanide difluorides on the basis of deuterium substitution and

This review summarizes the progress in organo-f-element vibrationalfrequencycalculationswithdensityfunctionaltheory
chemist rydurin gtheyear20 11.A continuin gt rendinorganolan- (DFT). Two dominant absorptions in th e 500c m−1 region were

thanide research is a strong emphasis on applications of identified as lanthanide–fluoride stretching modes for this very

organolanthanide complexes in homogeneous catalysis and, to a stronginfraredabsorption.Thepredominantlylanthanide–carbon

lesserextend,materialsscience.Roughly24%ofallrelevantpapers stretchingmodeswerefoundtofollowasimilartrendofincreas-
publis hedin2 011were inthe areaofo rgan oa cti nideche mistry, ing with m etal s ize an d hav e c haracte r istic 30 cm−1 de uterium
althought he latter conti nue sto prod uc eexcitingresult s. and 14cm −1 13 Ciso topic shift s.Theelectron ics tructurecalcula-

tions showed that these CH LnF complexes are not analogous
2 2

2. Lanthanides to the simple transition and actinide metal methylidenes with
me tal– carbon double bo nds that have been investigated p revi-

2.1. Lanthanidehydrocarbyls ously, because the lanthanide metals (in the +2 or +3 oxidation
state) donota ppea rtoforma (cid:3)-type bo ndw ith th eC H group.
2

2.1.1. Homolepticcompounds TheDFTandabinitiocorrelatedmolecularorbitaltheorycalcula-
Th e synthesis and reactivity of a series of homoleptic ˛- tion spre dict ed thatth esecompl exesexista smulti radical s,witha
metala tedN,N-dim eth ylbenzylam ine ra re-eart hm etalcomple xes Ln C (cid:4)bondan das ingle electronon C-2p we aklycoupled with fx
havebeen described.Thecompounds weresynth esized usingsalt (x=1 (C e),2(P r),3 ( Nd),etc .)electro ns inthe adjacen tLn-4fo rbital s.
meta thesis reactions betw een LnCl a nd ˛ -K(DMBA) (S chem e 1; Th e L n C(cid:4) bond i scom pose dofabou t1 5%L n-5d,6sa nd85 %C-sp2
Ln=Y,La,C e,Pr,Nd, Sm,Gd;D MBA3=N,N -dimethylbe nzylamid e). hyb ridor bi tal.Th e Lnorbital ha spred omi nantly6s and 5d char-
All s ev enc om ple xes were fou ndtob e freeofcoordinatingsolvent, acterw ithmor ed- cha racterf ore arlylanthanide sa ndin cre asing
and nofo rmationof anya nionic “a te ”spe cie swasobserv ed.The amou ntso fs-cha racteracros sth erow .TheLn Fbo nds arealmost
ligan ds intheseco mp lexe sdispla yed(cid:2) 4-coordi natio ntothem etal purelyio nic .According ly,thea rgo n–ne onm at rix shifts wer elarge
center[ 1] . (13–16 cm−1 )fortheionic Ln Fbondstre tching modes and small
Sub sequently, the reactivity of the Y and La derivatives was (∼1cm −1)for the mo recov ale nt Ln C bondstre tchingm ode s[2].
investigatedviav ario usprotono lys isre ac tion su singsilylam ines, Reac tionso fla ser- ablate dscandi um ,yt trium ,lanthanum ,ands ev-
anilines,and phe nolstog enerateadiv ersearray ofoth erhomolep- erallantha ni demetalatom swithdim ethyleth erhavebeen stu died
ticlantha nid ecomple xe sasillust r atedinS chem e 2[1]. usin gmatrixiso lation infrar edsp ectroscop y.Ide ntific ation softhe
major produ cts,Ln(CH OCH ) andCH OLnC H (Ln=Sc,Y,L a, Ce,
3 3 3 3

Gd, Tb, Yb, Lu), were supported by experiments with deuterium
2.1.2. Heterolepticcompounds
substitutionaswellastheoreticalcalculations.Itwasfoundthat
A matrix infrared spectroscopic and computational investi-
mostground-statemetalatomsreactwithdimethylethertogive
sgiantgiolen Lonf tCheb olnandtshahnaisdeb–emenethpyulbelniseh ecdominple2x0e1s1 .CLHa2sLenr-Fa2blwatiethd the L n(CH3OCH3) c omple xes sp ontan eousl y on anne aling, w hich
lantha nid e m etal a toms were condensed w ith CH 2F2 in excess disioamtioenriz(eF igto. 1th).eD CeHn3sOitLynfCuHn3ctiinosnearlticoanlc purlaotdiounctss rweviteha lveidsibthlea tirtrhae-
argon at 6K or neon at 4K. New infrared absorption bands
Ln(CH3OCH3)complexespossessC2vsymmetrywithmetalatoms

boundtotheoxygensideofdimethylether,andbentgeometries

were found for the inserted CH OLnCH molecules with direct
3 3

Ln O and C O bonds. All of these products were found to have

thesamegroundstatesastheircorrespondingmetalatomsexcept

forTb.AlthoughtheLu(CH OCH )complexhasbeenpredictedto
3 3

beastablemolecule,itwasnotobservedintheexperimentowing

tothelowenergybarrierforthesubsequentC Obondinsertion

reaction[3].

In a similar manner, lanthanide metal atoms, produced by
Scheme 1. Synthesis of ˛-Ln(DMBA)3. laser ab lation, h ave been condensed with CH3F in excess Ar at

Scheme 2. Protonolysis reactions of ˛-Ln(DMBA)3(Ar = 2,6-di-tert-butylphenyl, 4-tert-butylphenyl; Ar(cid:3)= 2,6-diisopropylphenyl, 4-tert-butylphenyl).
1124 F.T.Edelmann/CoordinationChemistryReviews257 (2013) 1122–1231

Fig. 1. Isomerization of Ln(CH3OCH3) complexes to the CH3OLnCH3insertion products with visible irradiation.
8K. New infrared absorption bands were assigned to the first Afour-memberedmetallacyclicspecieshasbeenidentifiedas

insertion CH LnF and oxidative addition methylene lanthanide oneofthereactionproductsinY[N(SiMe ) ] /KC reductionsys-
3 3 2 3 8
hydride fl uoride C H Ln HF produ cts on the basis of 13 C and deu- tem as illu stratedin Scheme 3[ 6].
2

terium substitution and density functional theory calculations Dihydrogen addition to a dinuclear rare-earth metal hydride

of the vibrational frequencies. It was also possible to observe complexsupportedbyametalatedTRENLigandhasbeeninves-
th e ca tionic speci es CH LnF+ f or som e Ln. For Ln= Eu and Yb, tigated.T hecomplic ate d reactionsy stem illustra ted inSch eme4
3

only CH LnF was observed. CH LnF in the Ln formal +2 oxida- involvesmono-anddialkylspeciesaswellashydridescontaining
3 3

tion state has been predicted to be more stable than CH LnHF themetalatedligand[7].
2

with the Ln in the formal +3 oxidation state (Fig. 2). CH -LnF A remarkable series of stable heteroleptic hydrocarbyl com-
3

was shown to form a single bond between Ln and C, being a plexes of divalent lanthanides have become accessible through

substitutedmethane.ItwasalsofoundthatsimilartoCH -LnF , theuseoftheverybulkypyrazolylborateligandhydrotris(3-tert-
2 2
CH -LnHFd oesnotfo rm a(cid:3) -bon dbetw een Lnand Ca ndisbest but yl-5- m ethy lpyra zolyl) borate(=TptBu,Me )accor dingtoScheme5.
2

describedas a LnHF-substitutedCH radical, with an unpaired p Treatment of the lanthanide(II) diiodides of samarium and
3
electrono nC w eaklyinteracting withtheunp aired fe lectronso n ytterbiumw ith KTp tBu,Meina1:1m olarratiofi rsta ffordedthe func-
the Ln. T he c alculate d potential ener gy s urface fo r the reacti on tionalizabl emo noiodidede r ivat ives(T ptBu,M e)Ln I(THF)n (Ln =Sm,
CH F+L a→ CH -LaF/CH -LaHFsh oweda number ofi nter mediates Yb; n=0, 1, 2). These w ere then tre ated with either KCH S iM e
3 3 2 2 3

andtransitionstatesonmultiplepaths.Thereactionmechanism or KCH(SiMe ) , respectively. Novel half-sandwich Yb(II) com-
3 2

involves the potential formation of LaF and LaHF intermediates plexescouldbeobtainedwithbothhydrocarbyls,CH(SiMe ) and
3 2

[4]. CH SiMe ,whilethecorrespondingsamarium(II)alkylswerestable
2 3

Similarly,lanthanidemetalatoms,producedbylaserablation, onlywiththebulkyCH(SiMe ) ligand[8].
3 2

werecondensedwithCHF (CDF )inexcessargonorneonat4K, The novel neutral phosphine-modified heteroscorpionate
3 3

andnewinfraredabsorptionswereassignedtotheoxidativeaddi- ligand(3,5-Me Pz) CHPPh anditsoxophosphineandiminophos-
2 2 2

tionproductfluoromethylenelanthanidedifluoridecomplexonthe phine heteroscorpionate derivatives have been synthesized for

basisofdeuteriumsubstitutionanddensityfunctionaltheoryfre- the first time. These neutral heteroscorpionate ligands dis-
quen cy calculation s.Twodomin ant bandsin the500c m−1reg ion play ed u nique chemis try towa rd rare-earth met al tris(al kyls)

havebeenidentifiedasmetal–fluorinestretchingmodes.Aband Ln(CH SiMe ) (THF) (Ln=Y,Lu,Sc).Thereactionbetweencom-
2 3 3 2
in th e mid -600cm−1 re gion was found to be dia gnostic fo r the pound 3,5-Me Pz CHPPh a nd Ln( CH S iMe ) (T HF) aff orded
2 2 2 2 3 3 2

unusualfluorinebridgebondC (F) Ln.Thecalculationsshowed heteroscorpionaterare-earthmetaltrialkyladductcomplexes.The

that most of the bridged HC(F)LnF structures are 3–6kcal/mol oxophosphineandiminophosphineprecursorsweretreatedwith
2

lower in energy than the open CHF-LnF structures, which is in Ln(CH SiMe ) (THF) togivetheunprecedentedzwitterionichet-
2 2 3 3 2

contrast to the open structures observed for the corresponding eroscorpionaterare-earthmetaldialkylsillustratedinScheme6.In

CH -LnF methylenelanthanidedifluorides.Argon-to-neonmatrix theprocess,theheteroscorpionatestransferredtothecarbanions
2 2
shifts were 15–16cm −1 to the blue for str etching of the almost bym eansof met hineC Hbondcleav agethatwa sa ttrib utedtothe
purely ionic Ln F bonds,as exp ecte d,b ut10cm−1 to the redfor pre sence of theelectr o n-w ithdr awinggr oups [9].

the bridge C (F) Ln stretching mode, which arises because Ar Similarly, a series of neutral rare-earth metal amides

binds more strongly to the electropositive Ln center, decreasing containing different achiral and chiral heteroscorpionate lig-

thebridgebonding,andthusallowingahigherC Fstretchingfre- ands were synthesized and characterized. Thus, treatment
que ncy(Fi g.3)[5]. of [ Ln{N(S iHMe ) } (TH F) ] (Ln=Nd, Sm) with acetamide
2 2 3 2

Fig. 2. Schematic representation of CH3EuF and CH2-TbHF.
F.T.Edelmann/CoordinationChemistryReviews257 (2013) 1122–1231 1125

Fig. 3. Calculated structures of the HC(F)YbF2(Ng)x(Ng = Ar, Ne, x = 1, 2) complexes.
or thioacetamide heteroscorpionate ligands for 2h at 0◦C Bimetallic “ate”-complexes of the type {LONR} Ln ((cid:5)-
aff orded the ˛-ago stic silylamido dim eric rare- eart h c om po unds Me) Li (TMED A) of yttrium, n eod ymium , and samarium2 w4ere
[Ln{N(Si HMe 2)2}(NNE) ]2 (Ln=Nd , Sm; N NE=hetero scorpionate subs4eq2uently pre2pare d accord ing to Schem e 10 by alkane elimi-

ligands, E=O, S), some as enantiopure complexes. These com- nation of the corresponding pro-ligand and [Li(TMEDA)][LnMe ]
4
plexes contain dianionic heteroscorpionate pseudoallyl ligands complexes. The resulting methyl “ate”-complexes were shown

resultingfromC Hactivationofthebridgingmethinegroupofthe by X-ray diffraction studies to be dimeric in the solid state. The

bis(pyrazol-1-yl)methanemoietyandsubsequentcoordinationto multidentate nature of the ligands in these dimeric species gen-

themetalcenter(Scheme7)[10]. eratesacis/transisomerismrelatedtothenitrogenatomsinthe

However, when the reaction was carried out for 1h at lower non-symmetricallycoordinatedamidinatefragments[11].

temperature new bis(silylamido) dimeric lanthanide compounds Unexpectedly, the reaction of [Li(TMEDA)][YbMe ] with
[Ln{N(SiHMe 2)2}2 (NNE)]2 (Ln = N d and Sm ; E = O) we re obtained {LONiPr}H2, carrie d ou t under co ndi tions identical to tho4se used
accordingtoScheme8.Thestructuresofthecomplexesweredeter- for the other lanthanide elements (Scheme 10), led to the isola-
minedby sp ectrosco pi cme thodsand th eX -raycrysta lstru ctures tion in 67%yi eldof{LON iPr} Yb ((cid:5) -Me) ((cid:5) -OH) Li (TM ED A) as
2 2 2 2 2 2
oftworepresentativecompoundswerealsoestablished[10]. pale yellow crystals (Scheme 11). The presence of adventitious

Aseriesoforgano-rare-earthmetalcomplexeswithmultiden- water and the extreme sensitivity of the putative intermediate
tate tethere d phenoxy-amidinat e ligan ds have be en sy nthesized {LONiP r} Y b ((cid:5) -Me) Li (TMEDA) w e reas sumedto bethemost
2 2 4 2 2
and structurally characterized. Scheme 9 shows the new ligands probablereasonsfortheoriginofthebridgingOHligandsinthis

whichhavebeenemployedinthisstudy[11]. compound[11].

Scheme3. Formationofafour-memberedmetallacyclicyttriumcomplex.
1126 F.T.Edelmann/CoordinationChemistryReviews257 (2013) 1122–1231

Scheme4. Synthesisandreactivityofcationiclutetiumhydrides.

A new yttrium monoalkyl complex supported by a bulky TheN-heterocycliccarbeneligatedscandiumtrialkylcomplexes
bis(a minoa lkyl)pyri dine ligand has been prepared acco rd ing to [{2,6-C H R NCH} C] Sc(CH S iMe ) (R=Me,iP r)have beensyn-
6 3 2 2 2 3 3

Scheme12.Thecompoundwasisolatedin77%yieldasapaleyellow thesizedbythereactionof1equiv.ofSc(CH SiMe ) (THF) with
2 3 3 2

solid[12]. thecorrespondingligand(2,6-C H R NCH) C(Scheme13).Their
6 3 2 2

Scheme5. SynthesisofTptBu,Me-stabilizedlanthanide(II)alkyls.
F.T.Edelmann/CoordinationChemistryReviews257 (2013) 1122–1231 1127

Scheme6. Synthesisofheteroscorpionate-supportedlanthanidedi-andtrialkyls.

molecularstructureshavebeenestablishedbysingle-crystalX-ray X is a halide. The “ate” complex (LLi)ScR was readily
diffraction [13]. ac ces sibl e and is best descr ibed as a Li carben3e add uct, ({1-
Carbon– siliconandcarbon–carbonbondformationsbyelimi- Li(THF)C(N Dipp CH CH N)}CH CM e O )S c(C H SiMe ) , since
2 2 2 2 2 3 3
nationreactionsatmetalN-heterocycliccarbenecomplexeshave structural characterization showed the alkoxide ligand bridging

beenreported(Scheme14).Itwasfoundthattwofunctionalgroups the two metals and the carbene Li-bound with the shortest yet

canbedeliveredatoncetoorgano-rare-earthcomplexes,(L)LnR2 recordedLi Cbonddistance[14].
and (L )2LnR (Ln =S c, Y; L =({1-C(NDippCH2 CH2N)}CH2C Me2O), The Li ca rb ene a dduct co uld be converted via lithium halide-
Dipp =2,6-iPr 2C6H 3 ; R= CH 2 SiMe3, CH2CMe3), via the addi- elimina tin g salt m etathe sis rea cti ons to alk ylat ed or s ilylated
tion o f E-X acros s th e metal– carbene bo nd to fo rm a imidazoliniu md erivatives,(L E)ScR (E= SiM e orCPh )a ccording
zwit terio nic imida zolini um–metal com plex, ( LE)LnR 2X, toScheme15[ 14]. 3 3 3
where LE= {1-EC(NDippCH2CH2N)}C H2CMe2O, E is a p- All the E- functionalized imidazolinium complexes sponta-

block functional group such as SiR3, PR2, or SnR3, and neously eliminated functionalized hydrocarbyl compounds upon

Scheme 7. Synthesis of [Ln{N(SiHMe2)2}(NNE)]2(Ln = Nd, Sm; NNE = heteroscorpionate ligands, E = O, S).
1128 F.T.Edelmann/CoordinationChemistryReviews257 (2013) 1122–1231

Scheme 8. Synthesis of [Ln{N(SiHMe2)2}2(NNE)]2(Ln = Nd and Sm; E = O).
warming to room temperature or slightly above, forming new

organicproductsER,i.e.,formingC Si,C P,andC Snbonds,and

re-formingtheinorganicmetalcarbene(L)LnR(X)or(L) LnXcom-
2

plex,respectively(Scheme16).Warmingthetris(alkyl)complexes
(LE)L nR formedo rganicp rodu ctsarising fro mC Cor C Sibond
3

formation, which appeared to proceed via the same elimination

route[14].
Tre atment of (L) Sc(CH SiMe ) with iodopentafluorobenzene Scheme9. Multidentatetetheredphenoxy-amidinateligands.
2 2 3
(Scheme 17) resulted in the “reverse sense” addition, which

rauenpvdoe nrr seitlbheleaersfmeudno lctyhtsieoi sni oafldoizormaatleikodann teoh feMt heme3NeSti-CahlHe 2taeIr,ry oal cgcyaocinlmi cpfaclaceirxlbi te(aLnt)ee2dgS crbo(yCu 6ptFhi5ne) Edforicl,l hoYlwbo)re ididn eb hyci orgemha pcytlieieoxlnde .sw Dciiteshp,m rLonetrCo-l(n3Ca(zTtxiHo)FLn)n xoC, fla fH(fTo-HCrdzFex)d (w Lthniteh= s YNix,a-ENcro,(oSYirbMd)i.enT3ah)t2ee,
theseteth eredsystems[14] . dialkylcom plexeswer ealsopreparedby2reacti ono f th ed ichlo ride
Re duction of carbo diimides RN C NR (R=iPr and Cy) by comple xeswith2 equiv .ofL iCH SiMe ( Scheme 20 ).Se veralnew
SmL2(THF), w hi ch was forme d in s itu by the reac tion of complexes were c haract er ized b2y X-r3ay crystal logra phy. Th e Er
Sm[N(TMS) 2]2(THF) 2with H2LinT HF (H2L =1,4 -bis( 2-hydroxy -3- andYbdial kylco mplexeswere fou ndtod isplayafive-coo rdin ate
tert-butyl-5-methyl-benzy l)pip er azidi ne),y ie ldedtheSm(III)com- trigo na l-bipyra midalgeom etry withth e Czxliga nd spanningboth
pfolerxiP wrNithC anN oiPxral(a=mDIiCd)inaantde tlhigeaSnmd (LIISIm)c[o(mN ipPlre)x2CwCi( tNhiaP rd)i2a]mSmidL o·cTaHrF- tahxeiaSl iaMned ognreo ueqpusastiotr oiavle sritthe ewci athrb tahz eo lCeH r2inSigM sey3streomt a.tTehde susochlu tthioant
benelig and LSm ((cid:5)-CyN CNC y)S mL·5.5 THFforC yN C NCy(=DCC, stru cture3s were f oun d to be consisten t wit h those in t he solid
Schem e18) .Thelatterwasthefirstexamp leo fab rid gedc arbene statebyNM Rsp ectrosc opy .Tr eatmentof they ttrium di alkyl with
Sm(III)c omp lexf ormed by the redu ctionofa ca rb odiimid e[15]. [Ph C ]+[ B(C F ) ]− cleanly produced t he alk yl catio nic com plex
tBuI2n) (a6 -sCimH2il)a]r2 Nm CaHn2nCeHr,2 aN rM eaec2t) iown iotfh YbiPL r(NTH F C)2N(LiP =r [ lOedC6H to2(2t,h4e- 2[(,C3z-3dx)imY(eCtHh2y6Slbi5Mut4ea3d)i]e+n[Be([C167F] 5.)4]−, but this spec ies did n ot insert
belreidctgreodn craerdbuecnteio ynttperrboicuemss coofmcap rlbeoxd (YiimbLi)d2e((cid:5)( S-cNh iPermCeN 1iP9r)) [v 1ia6 ]a. two- carbAa zoblies)(phwosapshinreop)coa rrtbedazotleo, rHeLa ct(HwL i=t h3,6-rtaBrue2--e1a,r8t-h(PPmh2e)t2a-l
The carbaz ole-bis(o xa zoline) li gand 1,8 -bis(4(cid:3),4(cid:3)- tris(amino benzyl ) complex es ( Ln[CH C H N Me -o] ) to afford
dimeth yloxazolin-2(cid:3)-yl)-3,6-di-tert-b utylcarbazo le (=H-Czx) the first PNP-carb azolide rare -earth m2e6tal4bis(al2kyl)3c om plexes,
wthaesfi pvere-cpoaorerddi naantde dtriaelaktyeldc owmitphl eLxne(sC(HC2zSxi)MLne(3C)H3(2T SHiMF)e23)t2o (Lanffo=rYd, LcoLnm [Cp6leHx 4CwHa2sN(cMhaer)a2c]2ter(iSz cehdembye 2X1-r; aLyn d=i Yff, r aScct,i oEnr).a nT ahley syisttraisuma

Scheme 10. Synthesis of the “ate” complexes {LONR}2Ln4((cid:5)-Me)4Li2(TMEDA)2.
F.T.Edelmann/CoordinationChemistryReviews257 (2013) 1122–1231 1129

Scheme 11. Formation of {LONiPr}2Yb2((cid:5)-Me)2(OH)2Li2(TMEDA)2.
Scheme12. Synthesisofamonoalkylyttriumbis(aminoalkyl)pyridinatecomplex.

solvent-free monomer, in which the carbazolide ligand coor- variousdeuteriumlabelingandkineticstudiesitwasdetermined
dinates to the Y3+ io n i n a (cid:6)P :(cid:6)N: (cid:6)P(cid:3)-tridentat e mod e and thatthe lattercomp lexform sth roughd irectme ta latio nexchange,
the two a mino benzyl g rou ps coordinate to the Y 3+ ion in a with no eviden ceofatr ansien timidoi nterm ediate.Allt hesereac-
(cid:2)1C :(cid:6)N-b identatemod es[18]. tions are summar ize d inSchem e22[1 9].
In a related s tudy, t he process of metallacycle ring open- Th e N -R-quinoliny l-8 -amino lig ands HL1–3 (R=2,6-iPr C H
2 6 3
ing h as been p robed i n de tail usin g a doubly orth o-me talated (HL1), 2,6-Et C H (HL2), 2,6-M e C H (HL3)) ha v e been pre-
2 6 3 2 6 3
lute tium arylc omplex .W hilere action of (LAr)Lu( THF)(LAr=ortho- pared, which reacted re adily with one equi v. of rare earth

metalated bis(phosphinimine)carbazolide) with bulky anilines metaltris(alkyl)stoaffordthecorrespondingbis(alkyl)complexes
(MesNH , TripNH )resultedindoublemet allacyc lering opening L1Y(CH SiMe ) ( TH F) and L1 −3Lu(CH SiMe ) (THF) via alkane
2 2 2 3 2 2 3 2

to generate the corresponding bis(anilide) lutetium complexes, elimination(Scheme23)[20].

utilization of the extremely sterically demanding Mes*NH pro- In contrast, treatment of the in situ generated neodymium
2
motedsing le meta llacyclerin gopening toaffordthe mono(anilide) trialk yl with H L1 afforde d a m ono alky l neodymi um complex

complex exclusively. The latter product was found to be highly (Scheme24)[20].

thermallysensitiveandrapidlyunderwentanunusualmetalation In a similar manner, the scandium alkyl complex

exchangeprocesstogiveastructuralisomerinhighyield.Through (Me TACD)Sc(CH SiMe ) wasobtainedbyaprotonationreaction
3 2 3 2

Scheme13. SynthesisofN-heterocycliccarbenescandiumtrialkylcomplexes.
1130 F.T.Edelmann/CoordinationChemistryReviews257 (2013) 1122–1231

Scheme14. SynthesisoflanthanideN-heterocycliccarbenecomplexes.

of the cyclic polyamine 1,4,7-trimethyl-1,4,7,10- Treatment of the rare-earth metal trialkyl complexes

tetraazacyclododecane((=Me TACD)H)withSc(CH SiMe ) (THF) Ln(CH SiMe ) (THF) (Ln=Sc,Y,Lu)with1equiv.of1,4-diazadiene
3 2 3 3 2 3 3 2
inbenzene-d (Scheme 25)[21]. ligands2,6-R C H N CH CH N C H R - 2 ,6(R= iP r,Me)afforded
6 2 6 3 6 3 2

Monoalkyl yttrium complexes containing tridentate pyridyl- straightforwardly the imino-amido rare-earth metal dialkyl

1-azaallyl dianionic ligands have been prepared according complexesshowninScheme29in65–85%isolatedyields[24].

to Scheme 26 by alkane elimination reactions between A mechanism involving intramolecular alkyl and hydrogen

Y(CH SiMe ) (THF) and the protonated ligand precursors migration, illustrated in Scheme 30, was supported on the basis
2 3 3 2

[22]. of DFT calculations to account for the ligand alkylation. The 2,6-

Subsequentreactionsofthemonoalkylyttriumcomplexeswith dimethylphenyl-substituted imino-amido lutetium complex was

oneequivalentof2,6-diisopropylanilineproducedthecorrespond- used as a model. It is clear that the isomerization of the tri-

ingmonoanilidecomplexesviahighlyselectiveprotonolysisofthe alkylcomplexainvolvestwosteps.Inthefirstone,a CH SiMe
2 3

terminalalkylY-CH SiMe bond(Scheme27)[22]. group transfers from the lutetium to a carbon atom forming
2 3

Anewscandiumalkylcomplexbearingabulkyphosphinimino- an intermediate b. In the second step, a hydrogen atom shifts

amine ligand has been prepared as outlined in Scheme 28. fromthecarbonatomconnectedwiththetransferred CH SiMe
2 3

The solid-state structure of the product was determined by X- group to the nearby carbon atom yielding the final product

ray diffraction analysis to be a monomeric THF-free scandium [24].
dial kyl, in agre ement w ith its s olution-state structure . The Sc3+ The synthesis, structure, and reactivity of the
ion is c hel ated by a N ,N-bid en tate ligand and two cis-p ositi oned yttrium anilid o hydri de [LY{NH(DI PP)}((cid:5) -H)]
2
alky l groups, g en er ating a four-c oordina te t etrah edral geome- (L=[Me C(N(DIPP))CHC (Me)(NCH CH NMe )]−, DIPP=2,6-
2 2 2
try. Treatmen t of the d ia lkyl with an eq uimolar am ount of iPr C H ) have been reported. A proto nolysis rea c tion
2 6 3

[Ph C][B(C F ) ] yielded the corresponding cationic monoalkyl of the yttrium dialkyl LY(CH SiMe ) with 1equiv. of
3 6 5 4 2 3 2

species[23]. 2,6-diisopropylaniline gave the yttrium anilido alkyl
F.T.Edelmann/CoordinationChemistryReviews257 (2013) 1122–1231 1131

Scheme 15. Formation of C Si and C C bonds from the addition of Group 14 halides to [(L)MR2]2.
LY[NH(DIPP)](CH SiMe ), and a subsequent (cid:4)-bond metathesis formationofthereactionproductwithtBuN(C,whichistheonly
2 3

reaction of the monoalkyl intermediate with 1equiv. compoundintheseriescontaininganY Cbond[25].

of PhSiH afforded the dimeric yttrium anilido hydride Inthecourseofarelatedinvestigation,anewscandiumimido
3
[LY {NH(DIPP)}((cid:5)-H)] as s hown in S cheme 31 . The str ucture of comp lexh asbee ns yn thesize dviathereacti o nseq uenceillus trated
2
[LY{NH(DIPP)}((cid:5)-H)] wa scharac ter izedbyX -ray crys tallograph y, inSchem e33 .Sca ndiummono -a nd bis-alkyls serveda sinterme-
2
whichshowedthatthecom plexisa(cid:5)-H dim er[2 5]. dia tesinth iss yntheticro ute[26 ].
The dimeric hyd ride [LY{NH( DI PP )}((cid:5) -H)] showedhighreac- An att emp tedsynth esisof tris((cid:2)-diketiminato)lanthanidecom-
2
tivityto wardav arietyo funsaturatedsubstrates,includi ngim ines, plexes Ln(L2,6−M e2) (L2,6 −M e2=[{N(C H Me -2,6)C(Me)} C H]−)
3 6 3 2 2

azobenzene, carbodiimides, isocyanides, ketones, and Mo(CO) , resultedinliganddeprotonation,anddifferentoutcomesdepend-
6

givingsomestructurallyintriguingproducts.Scheme32showsthe ingonthecentralmetalusedwereobserved.ReactionofYbCl with
3

Scheme16. ReactivityofscandiumN-heterocycliccarbenecomplexes.