ArticleFigure5.Cyclic(a)anddifferentialpulse(b)voltammogramsofcomplex-9d1inCH2Cl2with0.1Mn-Bu4NClO4atascanrateof0.10Vs.

oxidationprocesses,givingrisetoredoxwavesatEþ0.16VandEp,a=p,a=þ0.81V,respectively.Thelargesepara-tionoftheprocess(ΔE=0.65V)for9destablishesthattheoxidizedspeciesarestableinsolutionandshouldcorres-pondtotheformationof[μ-(1,4-phenylenediisocyanide){Os-(CHC(PPh3)CHCClCH)Cl(PPh3)2}2]3þand[μ-(1,4-phenyl-enediisocyanide){Os(CHC(PPh3)CHCClCH)Cl(PPh3)2}2]4þ,respectively.5nInthiscontext,itisworthytonotethatthecommunicationsbetweenthearomaticosmabenzeneringsys-temsin9dmaybeprecludedduetotheperpendicularorienta-tionbetweenthebridgingphenylringandtheosmabezenerings,whichhasalreadybeenconfirmedbyX-raycrystal-lographicstudy.

Conclusion

Thoughtherehavebeenmanymetallabenzenecomplexessynthesizedsofar,bismetallabenzenesandtheiranaloguesarerareandthestudiesoftheirphysicalpropertiesarestillratherlimited.Inthiswork,wehavesuccessfullyconstructedaseriesofdiisocyanide-bridgedbisosmabenzeneseithervialigandsubstitutionreactionsofosmabenzenes[Os(CHC-(PPh3)CHC(PPh3)CH)Cl2(PPh3)2]OHwithvariousdiisocya-nidesorthroughsimilarligandsubstitutionreactionsoftheosmacycle[Os(CHdC(PPhfollowedbynucleophilicattack3)CH(OH)-η2-CtCH)Clatthecoordinated2(PPhalkyne.3)2]Electrochemicalstudieshaveshownthatbisosmabenzenes

Organometallics,Vol.29,No.13,20102923

[(μ-CN-R-NC){Os(CHC(PPh4,40-oxybisphenyl;9d3)CHCClCH)Cl(PPhR=1,4-phenylene)3)exhibit2}2]Cl(9cR=2metal-metalinteractionthroughtheconjugateddiisocya-nidebridgeandundergotwoconsecutive,chemicallyandelectrochemically,one-electronredoxprocesses.

ExperimentalSection

GeneralConsiderations.AllmanipulationswerecarriedoutatroomtemperatureunderanitrogenatmosphereusingstandardSchlenktechniques,unlessotherwisestated.Solventsweredistilledundernitrogenfromsodiumbenzophenone(diethylether,tetra-hydrofuran)orcalciumhydride(dichloromethane).Thestartingmaterials[Os(CHC(PPh3)CHC(PPh3)CH)Cl2(PPh3)2]OH(3),5n,21[Os(CHC(PPh23)C(OEt)O)Cl2(PPh3)2](6),230[Os(CHdC(PPh23,29CH)Cl-biphenyldiisocya-3)-CH(OH)-η-Ctnide(4a),4,40-diisocyanodiphenylmethane2(PPh3)2](8),5n,214,4(4b),30bis(4-iso-cyanophenyl)ether(4c),31and1,4-phenylenediisocyanide(4d)22,32were0synthesizedbyliteratureprocedures.4,40-Biphenylamine,4,4-diaminobiphenylmethane,and4,40-diaminobiphenyletherwerepurchasedfromSigma-AldrichandAlfaAesar.Columnchromatographywasperformedonneutralalumina(200-300mesh).AlltheNMRspectrawererecordedwithaBrukerAV300(1H300.11MHz;13C75.5MHz;31P121.5MHz)oraBrukerAV400(H400.1MHz;13C100.6MHz;31P162.0MHz)spectro-meter.131

Hand13CNMRchemicalshiftsarerelativetoTMS,andPNMRchemicalshiftsarerelativeto85%HanalysesdatawereobtainedonaThermoQuest3POItalia4.ElementalSPAEA1110instrument.Samplesforinfraredspectroscopywerepreparedaspellets(KBr),withspectraacquiredonNicoletAvatar370spectrometers,ThermoElectronCorporation,U.S.A.

Cyclicvoltammetrywasperformedatroomtemperature(25οC)underNNClO2atmosphereinfreshlydistilledCH2Cl2containing0.1MBu44(TBAP),usingaCHI660Avoltammetricanalyzer.Athree-electrodesysteminasingle-compartmentcellwithresistancecompensationwasusedthroughout.Theworkingelectrodewasaglassycarbondisk(diameter=3mm).Thiselectrodewascarefullypolishedwith1mm,0.3mm,and0.05mmaluminapowderandultrasonicallyrinsedwithdistilledwaterandethanolbeforeeachrun.Theauxiliaryelectrodewasaplatinumsheet,andthereferenceelectrodewasAg/AgClinCH2Cl2with0.1MTBAP.Theferro-cene/ferroceniumredoxcouplewaslocatedat0.39Vunderourexperimentalconditions.

CAUTION!Theaminobiphenylsareverycarcinogenicmateri-alsandmustbehandledwithextremecare.Additionally,allisocyanidepreparationsshouldbeconductedinafumehoodowingtothetoxicgas.

[μ-(4,40-Biphenyldiisocyanide){Os(CHC(PPh3)CHC(PPhCH)ClToasolutionofcomplex3(0.323)-2(PPh3)}2][PF6]2(5a).g,0.23mmol)indrydichloromethane(30mL)wereadded4,40-biphenyldiisocyanide(4a)(23mg,0.12mmol)andNH(38mg,0.23mmol).Thesolutionwasstirredfor0.5hatroom4PF6temperature.Afterfiltration,thesolutionwasconcentratedtoca.5mL.Diethyletherwasaddedslowlytogiveagreenprecipitate,whichwascollectedbyfiltration.Recrystallizationofthecrudeproductfromdichloromethane/diethylethergave5aasadeepgreensolid.Yield:0.18g,371%.1HNMR((CD300.1MHz):δ(ppm)17.40(d,J(PH)=18.6Hz,23)H,2-CO,OsCH),15.69(d,3J(PH)=25.2Hz,2H,OsCH),9.09(t,3J(PH)=12.7Hz,2H,OsCHC(PPh3)CH),6.54-8.12(m,98H,PPh

3

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