Raj Ghadwal

Raj Ghadwal
Bielefeld University · Anorganische Chemie und Strukturelle Chemie

Priv.-Doz. Dr.

About

105
Publications
4,484
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,895
Citations
Introduction
We are a synthetic inorganic/ organometallic group and aim at the synthesis of new molecules featuring a low-valent main-group element(s), particularly from Group 13-15, and exploration of their structure, reactivity, and physical (optical, magnetic, and electronic) properties. A special emphasis is given to the activation and/ or functionalization of small molecules as a sustainable means to access new valuable compounds. Developing open-shell molecular systems for advanced functional materials and designing new ligand sets for more efficient and selective catalytic structures are among the other topics we are currently working on.
Additional affiliations
August 2015 - present
Universität Bielefeld
Position
  • Research Group Leader (Molecular Inorganic Chemistry and Catalysis Group)
April 2011 - July 2015
Georg-August-Universität Göttingen
Position
  • Georg-August-Universität Göttingen
Description
  • Research Group Leader
March 2008 - March 2011
Georg-August-Universität Göttingen
Position
  • PostDoc Position

Publications

Publications (105)
Article
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...
Article
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)...
Article
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)...
Article
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...
Article
Full-text available
Mesoionic dithiolates [(MIDt Ar )Li(LiBr) 2 (THF) 3 ] (MIDt Ar = {SC(NDipp)} 2 CAr; Dipp = 2,6‐ i Pr 2 C 6 H 3 ; Ar = Ph 3a , 3‐MeC 6 H 4 (3‐Tol) 3b , 4‐Me 2 NC 6 H 4 (DMP) 3c ) and [(MIDt Ph )Li(THF) 2 ] ( 4 ) are readily accessible (in ≥ 90% yields) as crystalline solids on treatments of anionic dicarbenes Li(ADC Ar ) ( 2a‐c ) (ADC Ar = {C(NDipp)...
Article
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...
Article
Full-text available
1,4-Diarsinine-1,4-diide compound [(ADC Ph )As] 2 ( 5 ) (ADC Ph = {C(DippN)} 2 CPh, Dipp = 2,6- i Pr 2 C 6 H 3 ) with a planar C 4 As 2 -ring fused between two 1,3-imidazole scaffolds has been isolated as a red crystalline solid. Compound 5 , formally comprising an 8π-electron C 4 As 2 -ring, is antiaromatic and undergoes 2e-oxidation with AgOTf to...
Article
Full-text available
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...
Article
Full-text available
Metalloradicals are key species in synthesis, catalysis, and bioinorganic chemistry. Herein, two iron radical cation complexes ( 3‐E )GaCl 4 [( 3‐E ) •+ = [{(IPr)C(Ph)E} 2 Fe(CO) 3 ] •+ , E = P or As; IPr = C{(NDipp)CH} 2 , Dipp = 2,6‐ i Pr 2 C 6 H 3 ] are reported as crystalline solids. Treatment of the divinyldipnictenes {(IPr)C(Ph)E} 2 ( 1‐E ) w...
Article
Full-text available
The first Sn(I) diradical [(ADC Ph )Sn] 2 ( 4 ) based on an anionic dicarbene (ADC Ph = {CN(Dipp)} 2 CPh; Dipp = 2,6‐ i Pr 2 C 6 H 3 ) scaffold has been isolated as a green crystalline solid by KC 8 reduction of the corresponding bis‐chlorostannylene [(ADC Ph )SnCl] 2 ( 3 ). The six‐membered C 4 Sn 2 ‐ring of 4 containing 6π‐electrons shows a diatr...
Article
Full-text available
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...
Article
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...
Article
Full-text available
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...
Article
Full-text available
Herein, we report the first 1,4-diphosphinine-1,4-diide compound [(ADC Ph )P] 2 ( 5-Ph ) (ADC Ph = PhC{(NDipp)C} 2 ; Dipp = 2,6-iPr 2 C 6 H 3 ) derived from an anionic dicarbene (ADC Ph ) as a red crystalline solid. Compound 5-Ph containing a 16π-electron planar fused-tricyclic ring system was obtained by the 4e reduction of [(ADC Ph )PCl 2 ] 2 ( 4...
Article
Full-text available
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...
Article
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...
Article
Full-text available
Crystalline 1,4‐distannabarrelene compounds [(ADC Ar ) 3 Sn 2 ]SnCl 3 ( 3‐Ar ) (ADC Ar = {CC(NDipp)CAr}; Dipp = 2,6‐iPr 2 C 6 H 3 , Ar = Ph or DMP; DMP = 4‐Me 2 NC 6 H 4 ) derived from anionic dicarbenes Li(ADC Ar ) ( 2‐Ar ) (Ar = Ph or DMP) have been reported. The cationic moiety of 3‐Ar features a barrelene framework with three coordinated Sn(II)...
Article
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...
Article
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.
Article
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...
Article
Full-text available
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...
Article
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....
Article
Full-text available
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...
Article
Full-text available
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;...
Article
Full-text available
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...
Article
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...
Article
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...
Article
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-iPr2 C6 H3 ), 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 divinyldipho...
Article
The first divinyldiarsenes [{(NHC)C(Ph)}As]2 (NHC = IPr 3a, SIPr 3b; IPr = C{(NAr)CH}2; SIPr = C{(NAr)CH2}2; Ar = 2,6‐iPr2C6H3) are reported. 3a and 3b were prepared by the reduction of corresponding chlorides {(NHC)C(Ph)}AsCl2 (NHC = IPr 2a, SIPr 2b) with Mg. Calculations revealed a small HOMO‐LUMO energy gap of 3.86 eV (3a) and 4.24 eV (3b). Trea...
Article
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...
Article
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...
Article
Full-text available
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...
Article
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...
Article
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...
Article
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...
Article
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...
Article
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...
Article
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.
Article
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...
Article
Full-text available
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...
Article
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,...
Article
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...
Article
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...
Article
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...
Article
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...
Article
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...
Article
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...
Article
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...
Article
Full-text available
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 (...
Article
Full-text available
Brønsted acid HNTf2 (Tf = SO2CF3) mediated dehydrogenative hydride abstraction from (L1)BH3 (3) and (L2)BH3 (4) (L1 = IPrCH2 = 1,3-(2,6-di-isopropylphenyl)imidazol-2-methylidene (1); L2 = SIPrCH2 = 1,3-(2,6-di-isopropylphenyl)imidazolidin-2-meth-ylidiene (2)) affords thermally stable hydride bridged mono-cationic hydrido boron compounds [{(L1)BH2}2...
Article
Blocking the C2 position of an imidazole-derived classical N-heterocyclic carbene (NHC) with an aryl group is an essential strategy to establish a route to mesoionic carbenes (MICs), which coordinate to the metal via the C4 (or C5) carbon atom. An efficient catalytic route to MIC precursors by direct arylation of an NHC is reported. Treatment of 1,...
Article
Reaction of VO(OPri)(3) with HOCMe2(CH2)CMe2OH in 1 : 2 molar ratio affords dimeric homometallic glycolate complex, [VO(OGO)(OGOH)](2) (1) (where OGO = doubly deprotonated form of the 2,5-dimethy1-2,5-hexanediol). Reactions of (1) with different metal isoproposides in 1 : 2 molar ratio yield a novel class of heterobimetallic isopropoxideglycolate d...
Article
Carbenes are well established reactive intermediates and play an important role in organic synthesis, whereas the scope of borylenes is rather limited. Selective borylene insertion into a C–N bond to yield boryl-functionalized N-heterocyclic olefins (NHOs), [{N(Dipp)N(DippBH)CHCH}CCH2]2 (6) and [{N(Dipp)N(DippBPh)CHCH}CCH2][{N(Dipp)N(2-iPr-6-CHMeCH...
Article
The cover picture shows insertion of a borylene into a C–N bond with an N-heterocyclic olefin (NHO) ligand. Selective borylene insertion into a C–N bond to yield boryl-functionalized NHOs [{N(Dipp)N(DippBH)CHCH}CCH2]2 and [{N(Dipp)N(DippBPh)CHCH}CCH2][{N(Dipp)N(2-iPr-6-CHMeCH2BC6H3)CHCH}CCH2] (Dipp = 2,6-iPr2C6H3) is reported for the first time. (I...
Article
Functionalization of the C4 carbon of an imidazol-derived N-heterocyclic carbene (NHC) may allow fine-tuning of the electronic and steric properties of the C2 carbene center. A facile route to silyl-functionalized di-N-heterocyclic carbenes (Di-NHCs) is described. Treatment of the polymeric lithiated NHC, {Li(IPrH)}n (1) (Li(IPrH) = {(N(2,6-iPr2C6H...
Article
N-heterocyclic olefins (NHOs), IPrCH2 () and SIPrCH2 () (IPrCH2 = {N(2,6-iPr2C6H3)CH}2CCH2 and SIPrCH2 = {N(2,6-iPr2C6H3)CH2}2CCH2), react with HSiCl3 and afford IPrCH(SiHCl2) () and SIPrCH(SiHCl2) (), respectively. Compounds and have been isolated in almost quantitative yield. Interestingly, treatment of the silylene IPr·SiCl2 with also affords ,...
Article
The first carbonyl free mixed valence cobalt(i)/cobalt(ii) compound [2{2Co(i)(η(6)-C7H8)}](2+) [Co(ii)2Cl6](2-) () [ = PhC(N(t)Bu)2SiCl] was obtained by the reaction of four equivalents of anhydrous CoCl2 with five equivalents of N-heterocyclic chlorosilylene . In contrast, the reaction of with CoBr2 yielded [2CoBr2] (). Compound was formed by the...
Article
Full-text available
Functionalization of N-heterocyclic carbenes (NHCs) has an important influence on their stability, Lewis donor, and acceptor properties. In this study, we report on the selective functionalization of a four-membered N-heterocyclic bis-silylene (2,6-Ar2C6H3NSi:)2 () (Ar = 2,4,6-iPr3C6H2) with mono-oxygen sources N2O and Me3NO. Treatment of with N2O...
Article
Three- and five-membered rings that bear the (Si-C-S) and (Si-C-C-C-S) unit have been synthesized by the reactions of LSiCl (1; L=PhC(NtBu)(2) ) and L'Si (2; L'=CH{(CCH(2) )(CMe)(2,6-iPr(2) C(6) H(3) N)(2) }) with the thioketone 4,4'-bis(dimethylamino)thiobenzophenone. Treatment of 4,4'-bis(dimethylamino)thiobenzophenone with LSiCl at room tempera...
Article
Isolating stable compounds with low-valent main group elements have long been an attractive research topic, because several of these compounds can mimic transition metals in activating small molecules. In addition, compounds with heavier low-valent main group elements have fundamentally different electronic properties when compared with their light...
Article
The reactions of silylenes with organic azides are quite diverse, depending on the substituents of the silylene center and on the nature of the azide employed. Elusive silaimine with three-coordinate silicon atom L(1)SiN(2,6-Triip(2)-C(6)H(3)) (5) {L(1) = CH[(C═CH(2))(CMe)(2,6-iPr(2)C(6)H(3)N)(2)] and Triip = 2,4,6-triisopropylphenyl} was synthesiz...
Article
Stable N-heterocyclic silylene, (RNCMe:CHC(:CH2)NR)Si (1, R = 2,6-iPr2C6H3) undergo addn. of Ph3SiOH and C6F5OH yielding silicon(IV) pentacoordinate diketiminate complexes [(RNCMeCHCMeNR)SiH(OX)2] (2, 3, X = SiPh3, C6F5), which structure was detd. by single-crystal d-ray anal. Compds. 2 and 3 were formed by O-H bond activation of triphenylsilanol a...
Article
The three-membered silacyclic ring compounds LSi[N(2)(Ph)(2)]tBu (1), LSi[HCN(Ph)(2)]tBu (2) and LSi[C(2)(Ph)(2)]tBu (3) were obtained by the treatment of base stabilized monoalkylsilylenes LSitBu (L = PhC(NtBu)(2)) with PhN=NPh, PhN=CHPh and PhC≡CPh. The reaction of PhN=NPh and PhC≡CPh with LSitBu shows a different reactivity pattern with base sta...
Article
Full-text available
Formyl chloride (H(Cl)C=O) is unstable at room temperature and decomposes to HCl and CO. Silicon analogue of formyl chloride, silaformyl chloride IPr·SiH(Cl)=O·B(C(6)F(5))(3) (3) (IPr = 1,3-bis(2,6-diisopropyl-phenyl)imidazol-2-ylidene), was stabilized by Lewis donor-acceptor ligands. Compound 3 is not only the first stable acyclic silacarbonyl com...
Article
Full-text available
An abnormal N-heterocyclic carbene (aNHC) has been used as a Lewis base to initiate dismutation of trichlorosilane. This report presents the reactivity differences of a normal N-heterocyclic carbene (NHC) versus aNHC with heavier group 14 elements. Three novel compounds (NHC)(2)·SiCl(2)H(2) (2), aNHC·SiCl(2)H(2) (3), and aNHC·GeCl(2) (4) have been...
Article
Reactions of silylenes with org. substrates generally lead to Si(IV) compds. Ligand substitution at the Si(II) atom of silylene, without changing the formal +2 oxidn. state, is very rare. A straightforward route to functionalized silylenes LSiX (L = PhC(NtBu)2 and X = PPh2 (1), NPh2 (2), NCy2(3), NiPr2 (4), NMe2 (5), N(SiMe3)2 (6), OtBu (7)) is rep...
Article
The first base stabilized monoalkylsilylenes LSitBu (2) and LSi[C(SiMe(3))(3)] (3) (L = PhC(NtBu)(2)) were synthesized by the facile metathesis reactions of LitBu and KC(SiMe(3))(3) with LSiCl (1). The reaction of LSitBu (2) with N(2)O afforded the dimer [LSitBu(μ-O)](2) (4) which contains a four-membered Si(2)O(2) ring.
Article
Three transition-metal-carbonyl complexes [V(L)(CO)(3)(Cp)] (1), [Co(L)(CO)(Cp)] (2), and [Co(L(2))(CO)(3)](+)[CoCO)(4)](-) (3), each containing stable N-heterocyclic-chlorosilylene ligands (L; L=PhC(NtBu)(2)SiCl) were synthesized from [V(CO)(4)(Cp)], [Co(CO)(2)(Cp)], and Co(2)(CO)(8), respectively. Complexes 1-3 were characterized by NMR and IR sp...
Article
Silicon(II) fluoride is unstable; therefore, isolation of the stable species is highly challenging and was not successful during the last 45 years. SiF(2) is generally generated in the gas phase at very high temperatures (~1100-1200 °C) and low pressures and readily disproportionates or polymerizes. We accomplished the syntheses of stable silicon(I...
Article
The reaction of N-heterocyclic silylene (NHSi) L [L = CH{(C[double bond, length as m-dash]CH(2))(CMe)(2,6-iPr(2)C(6)H(3)N)(2)}Si] with benzoylhydrazine, 1,2-dicarbethoxyhydrazine, 1,2-diacetylhydrazine and 1,2-bis(tert-butoxycarbonyl)hydrazine in 1 : 1 molar ratio resulted in compounds 1-4 with an almost quantitative yield and five coordinate silic...
Article
A stable silicon analogue of an acid anhydride {PhC(Bu(t)N)(2)}Si{═O·B(C(6)F(5))(3)}O-Si(H){═O·B(C(6)F(5))(3)}{(NBu(t))(HNBu(t))CPh} (4) with a O═Si-O-Si═O core has been prepared by treating monochlorosilylene PhC(Bu(t)N)(2)SiCl (1) with H(2)O·B(C(6)F(5))(3) in the presence of NHC (NHC = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene). Compound 4...
Article
The H atom analogue muonium (Mu) has been used to explore the free radical reactivity of two novel chlorosilylenes. Spectroscopic and computational investigations show that Mu adds to the silicon in the NHC-stabilised dichlorosilylene. In contrast, Mu reacts at the carbon of a siladiazirene ring in the monochlorosilylene. Muon and Cl hyperfine cons...