Raj Ghadwal

Bielefeld University · Anorganische Chemie und Strukturelle Chemie

Diradicals based on a meta‐quinodimethane (m‐QDM) scaffold generally have a triplet ground state and are rather scarce. Herein, m‐QDM‐based non‐Kekulé diradicals [3,3′‐(NHC)2BP] (3‐NHC) (NHC = SIPr = C{N(Dipp)CH2}2; IPr = C{N(Dipp)CH}2, Me‐IPr = C{N(Dipp)CMe}2; Dipp = 2,6‐iPr2C6H3; BP = 1,1′‐C6H4C6H4) featuring N‐heterocyclic carbene (NHC) pendants...

N‐Heterocyclic carbene (NHC) analogues of Wittig hydrocarbon, [(NHC)(Stil)(NHC)] (3a‐c) (NHC = SIPr (1a) = C[N(Dipp)CH2]2, Dipp = 2,6‐iPr2C6H3; IPr (1b) = C[N(Dipp)CH]2; Me‐IPr (1c) = C[N(Dipp)CMe]2 and Stil = C6H4CHCHC6H4) have been reported as crystalline solids. 3a‐c are prepared by two‐electron reductions of the corresponding bis‐1,3‐imidazoli(...

Carbocyclic aluminium halides [(ADC)AlX2]2 (2‐X) (X=F, Cl, and I) based on an anionic dicarbene (ADC=PhC{N(Dipp)C}2, Dipp = 2,6‐iPr2C6H3) framework are prepared as crystalline solids by dehydrohalogenations of the alane [(ADC)AlH2]2 (1). KC8 reduction of 2‐I affords the peri‐annulated Al(III) compound [(ADCH)AlH]2 (4) (ADCH=PhC{N(Dipp)C2(DippH)N},...

Herein, reactivity studies of a cyclic bis‐hydridostannylene [(ADC)SnH]2 (1‐H2) (ADC=PhC{(NDipp)C}2; Dipp=2,6‐iPr2C6H3) with various unsaturated organic substrates are reported. Reactions of terminal alkynes (RC≡CH) with 1‐H2 afford mixed acetylide‐vinyl‐functionalized bis‐stannylenes via dehydrogenation and hydrostannylation. Treatment of 1‐H2 wit...

We report the room temperature dimerization of carbon monoxide mediated by C4/C5‐vicinal anionic dicarbenes Li(ADC) (ADC = ArC{(Dipp)NC}2; Dipp = 2,6‐iPr2C6H3; Ar = Ph, DMP (4‐Me2NC6H4), Bp (4‐PhC6H4)) to yield (E)‐ethene‐1,2‐bis(olate) (i.e. ⁻O−C=C−O⁻ = COen) bridged mesoionic carbene (iMIC) lithium compounds COen‐[(iMIC)Li]2 (COen‐[iMIC]2 = [ArC{...

We report the room temperature dimerization of carbon monoxide mediated by C4/C5‐vicinal anionic dicarbenes Li(ADC) (ADC = ArC{(Dipp)NC}2; Dipp = 2,6‐iPr2C6H3; Ar = Ph, DMP (4‐Me2NC6H4), Bp (4‐PhC6H4)) to yield (E)‐ethene‐1,2‐bis(olate) (i.e. –O–C=C–O– = COen) bridged mesoionic carbene (iMIC) lithium compounds (COen‐[(iMIC)Li]2) (COen‐[iMIC]2 = [Ar...

The first carbocyclic gallylene [(ADC)2Ga(GaI2)] and bis-gallylene [(ADC)Ga]2 (ADC = PhC{N(Dipp)C}2; Dipp = 2,6-iPr2C6H3) featuring a central C4Ga2 ring annulated between two 1,3-imidazole rings are prepared by KC8 reductions of...

Decarbonylation of a cyclic bis‐phosphaethynolatostannylene [(ADC)Sn(PCO)]2 based on an anionic dicarbene framework (ADC = PhC{N(Dipp)C}2; Dipp = 2,6‐iPr2C6H3) under UV light results in the formation of a Sn2P2 cluster compound [(ADC)SnP]2 as a green crystalline solid. The electronic structure of [(ADC)SnP]2 is analyzed by quantum‐chemical calculat...

Herein, ring‐opening of mesoionic carbenes (iMICs) (iMIC=[ArC{N(Dipp)}2C(SiMe3)C:) (Dipp=2,6‐iPr2C6H3, Ar=Ph, 4‐Me2NC6H4 or 4‐PhC6H4) based on an 1,3‐imidazole scaffold to yield N‐ethynylformimidamide (eFIM) derivatives as crystalline solids (eFIM={(Dipp)N=C(Ar)N(Dipp)}C≡CSiMe3) is reported. eFIMs are thermally stable under inert gas atmosphere and...

Cyclic organoalane compounds [(ADCAr)AlH2]2 (ADCAr = ArC{(DippN)C}2; Dipp = 2,6‐iPr2C6H3; Ar = Ph or 4‐PhC6H4 (Bp)) based on anionic dicarbene (ADC) frameworks have been reported as crystalline solids. Treatments of Li(ADCAr) with LiAlH4 at room temperature afford [(ADCAr)AlH2]2 with the concomitant release of LiH. Compounds [(ADCAr)AlH2]2 are stab...

Classical N‐heterocyclic carbenes (NHCs) featuring the carbene center at the C2‐position of 1,3‐imidazole framework (i.e. C2‐carbenes) are well acknowledged as very versatile neutral ligands in molecular as well as in materials sciences. The efficiency and success of NHCs in diverse areas is essentially attributed to their persuasive stereoelectron...

Klassische N‐heterocyclische Carbene (NHCs) mit dem Carbenzentrum an der C2‐Position des 1,3‐Imidazolgerüsts (d.h. C2‐Carbene) sind als vielseitige neutrale Liganden sowohl in der Molekularforschung als auch in den Materialwissenschaften bekannt. Die Effizienz und der Erfolg der NHCs in verschiedenen Bereichen ist im Wesentlichen auf ihre überzeuge...

The first 1,4‐distibabenzene‐1,4‐diide compound [(ADC)Sb]2 (5) based on an anionic dicarbene (ADC) (ADC=PhC{N(Dipp)C}2, Dipp=2,6‐iPr2C6H3) is reported as a bordeaux‐red solid. Compound 5, featuring a central six‐membered C4Sb2 ring with formally SbI atoms may be regarded as a base‐stabilized cyclic bis‐stibinidene in which each of the Sb atoms bear...

Stable anions based on classical N‐heterocyclic carbenes (NHCs) can be prepared by KC8‐reduction of the corresponding NHC radicals as reported by Diego M. Andrada, Rajendra S. Ghadwal et al. in their Research Article (DOI: 10.1002/ange.202215244). The key to the stability of these anions is the delocalization of the electron lone pair over the C2‐b...

Stable anions based on classical N‐heterocyclic carbenes (NHCs) can be prepared by KC8 reduction of the corresponding NHC radicals as reported by Diego M. Andrada, Rajendra S. Ghadwal, and co‐workers in their Research Article (e202215244). The key to the stability of these anions is the delocalization of the electron lone pair over the C2‐biphenyl...

The first 1,4‐distibinine‐1,4‐diide compound [(ADC)Sb]2 (5) based on an anionic dicarbene (ADC) (ADC = PhC{N(Dipp)C}2, Dipp = 2,6‐iPr2C6H3) is reported as a bordeaux‐red solid. Compound 5, featuring a central six‐membered C4Sb2 ring with formally Sb(I) atoms may be regarded as a base‐stabilized cyclic bis‐stibinidene in which each of the Sb atoms b...

Herein, the first stable anions K[SIPrBp] (4 a‐K) and K[IPrBp] (4 b‐K) (SIPrBp=BpC{N(Dipp)CH2}2, IPrBp=BpC{N(Dipp)CH}2; Bp=4‐PhC6H4; Dipp=2,6‐iPr2C6H3) derived from classical N‐heterocyclic carbenes (NHCs) (i.e. SIPr and IPr) have been isolated as violet crystalline solids. 4 a‐K and 4 b‐K are prepared by KC8 reduction of the neutral radicals [SIPr...

Herein, the first stable anions K[SIPrBp] (4a‐K) and K[IPrBp] (4b‐K) (SIPrBp = BpC{N(Dipp)CH2}2, IPrBp = BpC{N(Dipp)CH}2; Bp = 4‐PhC6H4; Dipp = 2,6‐iPr2C6H3) derived from classical N‐heterocyclic carbenes (NHCs) (i.e. SIPr and IPr) have been isolated as violet crystalline solids. 4a‐K and 4b‐K are prepared by KC8 reduction of the neutral radicals [...

Herein, we report on the synthesis, characterization, and reactivity studies of the first cyclic C2As2‐diradicaloid {(IPr)CAs}2 (6) (IPr = C{N(Dipp)CH}2; Dipp = 2,6‐iPr2C6H3). Treatment of (IPr)CH2 (1) with AsCl3 affords the Lewis adduct {(IPr)CH2}AsCl3 (2). Compound 2 undergoes stepwise dehydrochlorination to yield {(IPr)CH}AsCl2 (3) and {(IPr)CAs...

Dipnictenes are molecules comprising a double bond between two Group 15 elements (referred as pnictogens (Pn) = P, As, Sb, Bi). Over the last decades, the chemistry of dipnictenes has undergone a remarkable advance. This is largely because of the advancement of new ligand sets with distinct stereoelectronic properties. In general, classical dipnict...

Herein, we report on the synthesis, characterization, and reactivity studies of the first cyclic C 2 As 2 ‐diradicaloid {(IPr)CAs} 2 ( 6 ) (IPr = C{N(Dipp)CH} 2 ; Dipp = 2,6‐ i Pr 2 C 6 H 3 ). Treatment of (IPr)CH 2 ( 1 ) with AsCl 3 affords the Lewis adduct {(IPr)CH 2 }AsCl 3 ( 2 ). Compound 2 undergoes stepwise dehydrochlorination to yield {(IPr)...

Phosphino-functionalized mesoionic olefins (p-MIOs), (iMIC)CHR (iMIC = PhC{N(Dipp)}2C(PPh2)C, Dipp = 2,6-iPr2C6H3; R = H 4a or Ph 4b), derived from a 1,3-imidazole-based mesoionic carbene (iMIC) are reported. The p-MIOs 4a (blue) and 4b (green) are crystalline solids and have been characterized by NMR spectroscopy and X-ray diffraction as well as D...

Mesoionic dithiolates [(MIDtAr)Li(LiBr)2(THF)3] (MIDtAr={SC(NDipp)}2CAr; Dipp=2,6‐iPr2C6H3; Ar=Ph 3 a, 3‐MeC6H4 (3‐Tol) 3 b, 4‐Me2NC6H4 (DMP) 3 c) and [(MIDtPh)Li(THF)2] (4) are readily accessible (in≥90 % yields) as crystalline solids on treatments of anionic dicarbenes Li(ADCAr) (2 a‐c) (ADCAr={C(NDipp)2}2CAr) with elemental sulfur. 3 a‐c and 4 a...

ConspectusMolecules and materials with easily tunable electronic structures and properties are at the forefront of contemporary research. π-Conjugation is fundamental in organic chemistry and plays a key role in the design of molecular materials. In this Account, we showcase the applicability of N-heterocyclic vinyl (NHV) substituents based on clas...

1,4‐Diarsinine‐1,4‐diide compound [(ADCPh)As]2 (5) (ADCPh={C(DippN)}2CPh, Dipp=2,6‐iPr2C6H3) with a planar C4As2 ring fused between two 1,3‐imidazole scaffolds has been isolated as a red crystalline solid. Compound 5, formally comprising an 8π‐electron C4As2 ring, is antiaromatic and undergoes 2e‐oxidation with AgOTf to form the 6π‐electron aromati...

Die KC8-Reduktion eines hypervalenten Arsen-Heterozyklus 4 ergibt das 1,4-Diarsinin-1,4-diid 5 als roten kristallinen Feststoff. Der C4As2-Ring von 5, der formal acht π-Elektronen enthält, ist planar und zeigt antiaromatischen Charakter. Die Zwei-Elektronen-Oxidation von 5 mit AgOTf liefert die C4As2-Verbindung 6, die mit sechs π-Elektronen ein aro...

Metalloradicals are key species in synthesis, catalysis, and bioinorganic chemistry. Herein, two iron radical cation complexes (3‐E)GaCl4 [(3‐E).+ = [{(IPr)C(Ph)E}2Fe(CO)3].+, E = P or As; IPr = C{(NDipp)CH}2, Dipp = 2,6‐iPr2C6H3] are reported as crystalline solids. Treatment of the divinyldipnictenes {(IPr)C(Ph)E}2 (1‐E) with Fe2(CO)9 affords [{(I...

The first SnI diradical [(ADCPh)Sn]2 (4) based on an anionic dicarbene (ADCPh={CN(Dipp)}2CPh; Dipp=2,6‐iPr2C6H3) scaffold has been isolated as a green crystalline solid by KC8 reduction of the corresponding bis‐chlorostannylene [(ADCPh)SnCl]2 (3). The six‐membered C4Sn2‐ring of 4 containing six π‐electrons shows a diatropic ring current, thus 4 may...

Das 1,4‐Distannabenzol‐Derivat 4 mit zweifach koordinierten SnI‐Atomen wurde als grüner, kristalliner Feststoff isoliert. Der Grundzustand von 4 ist ein offenschaliges Singulett (OS) mit der Singulett‐Triplett‐Energielücke (ΔEOS–T) von 4.4 kcal mol⁻¹ (nach CASSCF, ΔES–T=6.6 kcal mol⁻¹). Folglich zeigt 4 ein Halbfeld‐EPR‐Signal bei 100 K und addiert...

Herein, we report the first 1,4‐diphosphinine‐1,4‐diide compound [(ADCPh)P]2 (5‐Ph) (ADCPh=PhC{(NDipp)C}2; Dipp=2,6‐iPr2C6H3) derived from an anionic dicarbene (ADCPh) as a red crystalline solid. Compound 5‐Ph containing a 16π‐electron planar fused‐tricyclic ring system was obtained by the 4e reduction of [(ADCPh)PCl2]2 (4‐Ph) with Mg (or KC8) in a...

The cyclic Ge(I) compound [(ADCPh)Ge]2 (4) (ADCPh = {CN(Dipp)}2CPh, Dipp = 2,6-iPr2C6H3) containing a 6π-electron C4Ge2 framework has been isolated as a red crystalline solid. CASSCF calculations reveal a closed-shell singlet ground state for 4 with a considerable diradical character (y = 34%). Thus, the diradicaloid 4 readily splits dihydrogen at...

Intramolecular 1,2‐Dipp migration of seven mesoionic carbenes (iMICAr) 2 a–g (iMICAr=ArC{N(Dipp)}2CHC; Ar=aryl; Dipp=2,6‐iPr2C6H3) under nickel catalysis to give 1,3‐imidazoles (IMDAr) 3 a–g (IMDAr=ArC{N(Dipp)CHC(Dipp)N}) has been reported. The formation of 3 indicates the cleavage of an N−CDipp bond and the subsequent formation of a C−CDipp bond i...

Super‐iMICs (5) mit dem bisher größten „Buried Volume“ (%Vbur=45) für iMICs sind über eine neuartige Ni‐katalysierte intramolekulare 1,2‐Dipp‐Wanderung von C5‐protonierten iMICs (2) zu 3, anschließende N‐Alkylierung von 3 und letztlich durch Deprotonierung von 4 zugänglich. S‐iMICs (5) sind stärkere σ‐Donoren und stärkere π‐Akzeptoren als 2. Eine k...

Crystalline 1,4‐distannabarrelene compounds [(ADCAr)3Sn2]SnCl3 (3‐Ar) (ADCAr={ArC(NDipp)2CC}; Dipp=2,6‐iPr2C6H3, Ar=Ph or DMP; DMP=4‐Me2NC6H4) derived from anionic dicarbenes Li(ADCAr) (2‐Ar) (Ar=Ph or DMP) have been reported. The cationic moiety of 3‐Ar features a barrelene framework with three coordinated SnII atoms at the 1,4‐positions, whereas...

Herein, the synthesis and characterization of dicationic dichalcogenide compounds [(SIPr)E] 2 (OTf) 2 ( 3a‐E ) (E = S, Se, Te) based on a saturated N‐heterocyclic carbene (NHC), SIPr (SIPr =:C{N(Dipp)CH 2 } 2 , Dipp = 2,6‐iPr 2 C 6 H 3 ) are reported. Treatment of SIPr ( 1a ) with elemental chalcogens affords the heavier ketone derivatives (SIPr)E...

Phosphinidene complexes of the general formula RPM(CO) n (R = an alkyl or aryl group; M = a transition metal) are electrophilic and thermally unstable. Thus, the isolation of these elusive species for structural elucidations remains a challenge. Herein, we report the first terminal phosphinidene complexes [{(NHC)C(Ph)}P]Fe(CO)4 [NHC = IPr = C{(NDip...

1,3-Imidazole-based mesoionic carbenes (iMICs) are a very promising class of carbon-donor ligands in synthesis and catalysis. However, a systematic study of the quantification of stereoelectronic properties of iMICs is lacking. This is most likely due to the absence of rational synthetic routes to suitable iMIC compounds. Herein, we report the synt...

2-Arsa-1,3-butadienes (L)As(cAACR) (L = PhC=C{(NDipp)CH}2, Dipp = 2,6-iPr2C6H3; cAACR = C{(NDipp)CMe2CH2C(R)}, R = Me2 2a, R = cyclohexyl (Cy) 2b) and the corresponding radical cations [(L)}As-(cAACR)]GaCl4 (R = Me2 3a, Cy 3b) and dications [(L)As(cAACR)]-(GaCl4)2 (R = Me 4a, Cy 4b) featuring a C=C‒As=C π-conjugated framework are reported.

The first C5-protonated 1,3-imidazol-based mesoionic carbene iMICBp (2) (iMICBp = :C{CH(NDipp)2C(Bp)}; Dipp = 2,6-iPr2C6H3; Bp = 4-PhC6H4) has been reported as a crystalline solid. Spectroscopic, X-ray diffraction, and computational studies...

A synthetic strategy for the 2-phospha-1,3-butadiene derivatives [{(IPr)C(Ph)}P(cAACMe)] (3a) and [{(IPr)C(Ph)}P(cAACCy)] (3b) (IPr = C{(NDipp)CH2}2, Dipp = 2,6-iPr2C6H3; cAACMe = C{(NDipp)CMe2CH2CMe2}; cAACCy = C{(NDipp)CMe2CH2C(Cy)}, Cy = cyclohexyl) containing a C=C‒P=C framework has been established. Compounds 3a and 3b have a remarkably small...

The first terminal arsinidene complexes [{(NHC)C(Ph)}As]Fe(CO)4 (NHC = IPr = C{(NDipp)CH}2 5, Me-IPr = C{(NDipp)CMe}2 6; Dipp = 2,6-iPr2C6H3) with a two-coordinated arsenic atom have been reported as crystalline solids....

The divinyldiarsene radical cations [{(NHC)C(Ph)}As]2(GaCl4) (NHC=IPr: C{(NDipp)CH}2 3; SIPr: C{(NDipp)CH2}2 4; Dipp=2,6‐iPr2C6H3) and dications [{(NHC)C(Ph)}As]2(GaCl4)2 (NHC=IPr 5; SIPr 6) are readily accessible as crystalline solids on sequential one‐electron oxidation of the corresponding divinyldiarsenes [{(NHC)C(Ph)}As]2 (NHC=IPr 1; SIPr 2) w...

A series of unique C2P3-ring compounds [(ADCAr)P3] (ADCAr = ArC{(DippN)C}2; Dipp = 2,6-iPr2C6H3; Ar = Ph 4a, 3-MeC6H44b, 4-MeC6H44c, and 4-Me2NC6H44d) are readily accessible in an almost quantitative yield by the direct functionalization of white phosphorus (P4) with appropriate anionic dicarbenes [Li(ADCAr)]. The formation of 1,2,3-triphosphol-2-i...

Die stufenweise Oxidation von Diarsenen [As2], die N‐heterocyclische Vinyl‐π‐Donorsubstituenten tragen, mit GaCl3 führt zur Bildung von Radikalkationen [As2]+. und Dikationen [As]²⁺ in kristallinen Feststoffen. Experimentelle und theoretische Studien bestätigen die Delokalisierung des ungepaarten Elektrons über das π‐konjugierte CAs2C‐Gerüst. Abst...

The synthesis and charcterization of the crystalline diphosphene radical cations [{(NHC)C(Ph)}P]2(GaCl4) (NHC = IPr = C{(NDipp)CH}2 3, SIPr = C{(NDipp)CH2}2 4; Dipp = 2,6-iPr2C6H3) and dications [{(NHC)C(Ph)}P]2¬(GaCl4)2 (NHC = IPr...

Carbon-centered radicals and diradicaloids based on classical N-heterocyclic carbene (NHC) scaffolds are readily accessible as crystalline solids. The presence of an aryl (Ar) substituent at the C2-position is the key to the remarkable stability of these open-shell species as it provides appropriate room for the spin-density delocalization. Two cat...

The first divinyldiarsenes [{(NHC)C(Ph)}As]2 (NHC=IPr 3 a, SIPr 3 b; IPr=C{(NAr)CH}2; SIPr=C{(NAr)CH2}2; Ar=2,6‐iPr2C6H3) are reported. Compounds 3 a and 3 b were prepared by the reduction of corresponding chlorides {(NHC)C(Ph)}AsCl2 (NHC=IPr 2 a, SIPr 2 b) with Mg. Calculations revealed a small HOMO–LUMO energy gap of 3.86 (3 a) and 4.24 eV (3 b)....

The olefinic C−H bond functionalization of (NHC)CHPh (NHC=IPr=C{(NAr)CH}2 1; SIPr=C{(NAr)CH2}2 2; Ar=2,6‐iPr2C6H3), derived from classical N‐heterocyclic carbenes (NHCs), with PCl3 affords the dichlorovinylphosphanes {(NHC)C(Ph)}PCl2 (NHC=IPr 3, SIPr 4). Two‐electron reduction of 3 and 4 with magnesium leads to the formation of the divinyldiphosphe...

Para‐quinodimethane (pQDM) is a fundamental structural component in many π‐conjugated organic molecules and materials. The incorporation of phosphorus atom into π‐conjugated frameworks offers unique opportunities for controlling the properties of derived species. A phosphorus analogue of p‐quinodimethane (pQDM), (IPrC)2P4 [5, IPr=C{N(Ar)CH2}2; Ar=2...

Two‐fold C‐C cross‐coupling of N‐heterocyclic carbenes (NHCs) (SIPr = C{NAr}2CH2CH2,1; IPr = C{NAr}2CHCH, 2; Me‐IPr = C{NAr)}2CMeCMe, 3; Ar = 2,6‐iPr2C6H3) with 4,4ʹʹ‐diiodo‐p‐terphenyl under Ni‐catalysis furnished [(SIPr)2(C6H4)3](I)2 (4), [(IPr)2(C6H4)3](I)2 (5), and [(Me‐IPr)2(C6H4)3](I)2 (6). Two electron reduction of 4‐6 with KC8 readily affor...

The direct double carbenylation of 1,4-diiodobenzene and 4,4′-dibromobiphenyl with a classical N-heterocyclic carbene, SIPr (1) (SIPr = :C{N(2,6-iPr2C6H3)}2CH2CH2) by means of nickel catalysis gives rise to 1,3-imidazolinium salts [(SIPr)(C6H4)(SIPr)](I)2 (2) and [(SIPr)(C6H4)2(SIPr)](Br)2 (3) as off-white solids. Two-electron reduction of 2 and 3...

Stable N-heterocyclic carbene analogues of Thiele and Chichibabin hydrocarbons, [(IPr)(C6 H4 )(IPr)] and [(IPr)(C6 H4 )2 (IPr)] (4 and 5, respectively; IPr=C{N(2,6-iPr2 C6 H3 )}2 CHCH), are reported. In a nickel-catalyzed double carbenylation of 1,4-Br2 C6 H4 and 4,4'-Br2 (C6 H4 )2 with IPr (1), [(IPr)(C6 H4 )(IPr)](Br)2 (2) and [(IPr)(C6 H4 )2 (IP...

Stable N‐heterocyclic carbene analogues of Thiele and Chichibabin hydrocarbons, [(IPr)(C6H4)(IPr)] and [(IPr)(C6H4)2(IPr)] (4 and 5, respectively; IPr=C{N(2,6‐iPr2C6H3)}2CHCH), are reported. In a nickel‐catalyzed double carbenylation of 1,4‐Br2C6H4 and 4,4′‐Br2(C6H4)2 with IPr (1), [(IPr)(C6H4)(IPr)](Br)2 (2) and [(IPr)(C6H4)2(IPr)](Br)2 (3) were g...

One electron reduction of C2-arylated 1,3-imidazoli(ni)um salts (IPrAr)Br (Ar = Ph, 3a; 4-DMP, 3b; 4-DMP = 4-Me2NC6H4) and (SIPrAr)I (Ar = Ph, 4a; 4-Tol, 4b) derived from classical NHCs (IPr = :C{N(2,6-iPr2C6H3)}2CHCH, 1; SIPr = :C{N(2,6- iPr2C6H3)}2CH2CH2, 2) gives radicals [(IPrAr)]* (Ar = Ph, 5a; 4-DMP, 5b) and [(SIPrAr)]* (Ar = Ph, 6a; 4-Tol, 6...

One electron reduction of C2-arylated 1,3-imidazoli(ni)um salts (IPrAr)Br (Ar = Ph, 3a; 4-DMP, 3b; 4-DMP = 4-Me2NC6H4) and (SIPrAr)I (Ar = Ph, 4a; 4-Tol, 4b) derived from classical NHCs (IPr = :C{N(2,6-iPr2C6H3)}2CHCH, 1; SIPr = :C{N(2,6- iPr2C6H3)}2CH2CH2, 2) gives radicals [(IPrAr)]* (Ar = Ph, 5a; 4-DMP, 5b) and [(SIPrAr)]* (Ar = Ph, 6a; 4-Tol, 6...

The first C5-protonated abnormal N-heterocyclic carbene (aNHC), PhC{N(2,6-iPr2C6H3)}2CHC: (4) is readily accessible by C4-deprotonation of [ArC{N(2,6-iPr2C6H3)}2CHCH]X (3a-X) (Ar = Ph, X = Br or I) with a base. The aNHC 4 is stable at 298 K in [D8]THF solution and has been spectroscopically characterized. The facile availability of 4 enables the sy...

Invited for the cover of this issue is the group of Rajendra S. Ghadwal at the University of Bielefeld. The image depicts the bridging of a silylene and a carbene, leading to the formation of the silylene-functionalized NHC (Si-NHC). Read the full text of the article at 10.1002/chem.201703530.

The incorporation of carbene (R2C:) and silylene (R2Si:) functionalities in the same molecule is a challenging task owing to their inherent reactivity. The synthesis of a stable compound (Si−NHC) featuring an unmasked carbene as well as a silylene is accomplished for the first time by installing a silylene functionality on the backbone of a 1,3-imi...

Cationic copper(I) complexes [Cu(aIPrPh)(IPr)]I (3) and [Cu(aIPrPh)2]I (4) featuring an abnormal N-heterocyclic carbene (aNHC) (aIPrPh = 1,3-bis(2,6-diisopropylphenyl)-2-phenylimidazol- 4-ylidene) and/or an NHC (IPr = 1,3-Bis(2,6-diisopropylphenyl)imidazol-2-ylidene) ligand(s) are reported. Treatment of Cu(aIPrPh)I (2) with IPr affords complex 3. R...

A highly efficient nickel catalysed method for the direct C2-arylation of N-heterocyclic carbenes (NHCs) is reported. This protocol enables a facile access to C2-arylated imidazolium salts (NHC-Ar)X (X = Cl,...

The synthesis, structure, and reactivity of the first silylene-functionalized N-heterocyclic carbene (Si-NHC), {(L1)Si}, (3) (L1 = PhC(NtBu)2; L2 = CCH(CNAr)2C:); Ar = 2,6-diisopropylphenyl) are reported. The ditopic carbanionic-NHC (dc-NHC), [Li(L2)]∞ (1) reacts with the monochlorosilylene (L1)SiCl (2) to afford 3. The HOMO of 3 is the silylene lo...

Four-membered biradicaloid compounds containing a N2E2 (E = main group element) framework have been thoroughly investigated, however the synthesis of stable analogues with a C2P2 skeleton remains a challenge. Base-mediated double C-H functionalization of IPr=CH2 (1) (IPr = C[N(2,6-iPr2-C6H3)CH]2) with PCl3 affords [{(IPr)CP}2Cl]Cl (2) as a royal bl...

The synthesis and characterization of N-heterocyclic carbene (NHC) stabilized-dichlorosilylene Group 6 metal complex {(IPr)SiCl2}W(CO)5 (3-W), {(IPr)SiCl2}2Cr(CO)4 (4-Cr), and {(IPr)SiCl2}2W(CO)4 (4-W) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) are reported. Treatment of 3-W with CsOH in the presence of IPr leads to the formation of a...

Deprotonation of [IPrPh]I (1) with Co{N(SiMe3)2}2 readily affords the abnormal N-heterocyclic carbene (aNHC) complex (aIPrPh)2CoI2 (2) (aIPrPh = 1,3-bis(2,6-iPr2C6H3)-2-phenyl-imidazol-4-ylidene). Treatment of 1 with NaHBEt3 yields (aIPrPh)BEt3 (3) that serves as an aNHC-transfer agent and yields (aIPrPh)Co{N(SiMe3)2}2 (4) on reaction with Co{N(SiM...

Reaction of a C2-arylated imidazolium iodide (IPrPh)I (1) (IPrPh = 1,3-bis(2,6-diisopropylpheny1)-2-phenyl-imidazolium) with PdCl2 in the presence of Ag2O affords abnormal N-heterocyclic carbene (aNHC) palladium complexes (aIPr(Ph))PdCl2 (2) and (aIPr(Ph))(2)PdCl2 (3) (aIPr(Ph) = 1,3-bis(2,6-diisopropylphenyl)-2-phenyl-imidazol-4-ylidene). Treatmen...

Treatment of imidazolium salts (IPrH)Cl (1) and (IPrH)I (2) with MeMgI leads to the formation of normal N-heterocyclic carbene (nNHC) compounds (IPr)MgCl(I) (3) and (IPr)MgI2 (4) [IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene], respectively. By employing a similar strategy, the first magnesium compound (aIPrPh)MgI2(OEt2) (6) featuring an a...

N-Heterocyclic carbenes (NHCs) are an important class of compounds that are indeed regarded as most versatile carbon-donor ligands in transition metal and organometallic catalysis. In addition, NHCs are also capable of stabilizing a variety of highly reactive main group compounds with intriguing properties. The enormous success of NHCs prompted the...

Reaction of Ti(OPri)4 with 2-methyl-2,4-pentanediol [HOGOH, where G = CMe2CH2CH(Me)] in 1 : 3 M ratio under reflux afforded the monomeric [Ti(OGO)(OGOH)2] (1), which on further reactions with [Al(OPri)3] or [Nb(OPri)5] in 1 : 1 and 1 : 2 M ratios afforded heterometallic derivatives, [Ti(OGO)3{M(OPri)n−2}] and [Ti(OGO)3{M(OPri)n−1}2] [where M = Al (...