@article {44417, title = {Access to silicon(II)- and germanium(II)-indium compounds}, journal = {Organometallics}, volume = {37}, year = {2018}, month = {APR}, pages = {1206-1213}, abstract = {Despite the remarkable ability of N-heterocyclic silylene to act as a Lewis base and form stable Lewis adducts with group 13 elements such as boron, aluminum, and gallium, there has been no such comparable investigation with indium and the realization of a stable silylene-indium complex has still remained elusive. Similarly, a germylene-indium complex is also presently unknown. We describe herein the reactions of [PhC(NtBu)(2)SiN-(SiMe3)(2)] (1) and [PhC(NtBu)(2)GeN(SiMe3)(2)] (4) with InCl3 and InBr3 that have resulted in the first silylene-indium complexes, [PhC(NtBu)(2)Si{N(SiMe3)(2)}-> InCl3] (2) and [PhC(NtBu)(2)Si{N(SiMe3)(2)}-> InBr3] (3), as well as the first germylene-indium complexes, [PhC(NtBu)(2)Ge{N(SiMe3)(2)}-> InCl3] (5) and [PhC(NtBu)(2)Ge{N(SiMe3)(2)}-> InBr3] (6). The solid-state structures of all species have been validated by single-crystal X-ray diffraction studies. Note that 5 and 6 are the first structurally characterized organometallic compounds that feature a Ge-In single bond (apart from the compounds in Zintl phases). Theoretical calculations reveal that the Si(II)-> In bonds in 2 and 3 and the Ge(II)-> In bonds in 5 and 6 are dative bonds.}, doi = {10.1021/acs.organomet.8b00093}, author = {Pahar, Sanjukta and Karak, Suvendu and Pait, Moumita and Raj, K. Vipin and Vanka, Kumar and Sen, Sakya S.} } @article {46680, title = {Access to diverse germylenes and a six-membered dialane with a flexible beta-diketiminate}, journal = {Chemical Communications}, volume = {56}, year = {2020}, month = {OCT}, pages = {11871-11874}, type = {Article}, abstract = {

A nacnac-based tridentate ligand containing a picolyl group (L) was employed to isolate chlorogermylene (1). The reaction of1with another equivalent of GeCl2 center dot dioxane surprisingly gave pyridylpyrrolide-based chlorogermylene (2)viaC-N bond cleavage and C-C coupling, while with AlCl3, it afforded a transmetalated product,4. The reaction of L with AlH3 center dot NMe2Et led to an unusual cyclohexane type six-membered dialane heterocycle (5).

}, issn = {1359-7345}, doi = {10.1039/d0cc05202g}, author = {Pahar, Sanjukta and Swamy, V. S. V. S. N. and Das, Tamal and Gonnade, Rajesh G. and Vanka, Kumar and Sen, Sakya S.} } @article {46716, title = {Amidinato germylene-zinc complexes: synthesis, bonding, and reactivity}, journal = {Chemistry-An Asian Journal}, volume = {15}, year = {2020}, month = {OCT }, pages = {3116-3121}, type = {Article}, abstract = {

Despite the explosive growth of germylene compounds as ligands in transition metal complexes, there is a modicum of precedence for the germylene zinc complexes. In this work, the synthesis and characterization of new germylene zinc complexes [PhC(NtBu)(2)Ge{N(SiMe3)(2)}-\> ZnX2](2)(X= Br (2) and I (3)) supported by (benz)-amidinato germylene ligands are reported. The solid-state structures of2and3have been validated by single-crystal X-ray diffraction studies, which revealed the dimeric nature of the complexes, with distorted tetrahedral geometries around the Ge and Zn center. DFT calculations reveal that the Ge-Zn bonds in2and3are dative in nature. The reaction of2with elemental sulfur resulted in the first structurally characterized germathione stabilized ZnBr(2)complexes PhC(NtBu)(2)Ge(=S){N(SiMe3)(2)}-\> ZnBr2(5). Therefore, the Ge=S in5is in-between Ge-S single and Ge=S double bond length, owing to the coordination of a sulfur lone pair of electrons to ZnBr2.

}, keywords = {DFT, Germathione, Germylene, X-ray Structure, zinc}, issn = {1861-4728}, doi = {10.1002/asia.202000807, Early Access Date = SEP 2020}, author = {Yadav, Sandeep and Kumar, Rohit and Raj, K. Vipin and Yadav, Prashant and Vanka, Kumar and Sen, Sakya S.} } @article {47595, title = {Access to a variety of Ge(II) and Sn(II) compounds through substitution of hypersilyl moiety}, journal = {Organometallics}, volume = {40}, year = {2021}, month = {AUG }, pages = {2651-2657}, type = {Article}, abstract = {We have prepared amidinato-germylene (3) and -stannylene (4) with a tris(trimethylsilyl)silyl substituent and subsequently substituted the hypersilyl moiety by reacting 3 with chlorophosphines, which led to phosphino germylenes (5 and 6) with concomitant liberation of (Me3Si)(3)SiCl. Exploiting the fluoride affinity of the silicon atom, we have prepared pentafluoropyridyl germylene (7) and -stannylene (8) by reacting 3 and 4 with C5F5N with simultaneous elimination of (Me3Si)(3)SiF. These are the first examples of aryl germylenes or stannylenes prepared via C-F bond activation of a perfluoroarene. The reaction of 4 with Me3NO resulted in a novel Sn2O2 ring (9). All compounds were characterized by single-crystal X-ray structure determination studies.}, issn = {0276-7333}, doi = {10.1021/acs.organomet.1c00306}, author = {Bisai, Milan Kumar and Ajithkumar, V. S. and Gonnade, Rajesh G. and Sen, Sakya S.} } @article {48753, title = {Activation of the olefinic C-H bond of NHC and NHO by perimidine-based silicon and germanium compounds}, journal = {Organometallics}, volume = {42}, year = {2023}, month = {JUL}, pages = {1909-1917}, type = {Article}, abstract = {

In this manuscript, several backbonegermylene-functionalized zwitterioniccompounds were prepared conveniently from the corresponding N-heterocycliccarbenes or N-heterocyclic olefins in a single step through backboneC-H activation. Our initial motivation was to generate a silylenefrom C10H6(Me3SiN)(2)SiHCl(2) using ItBu [ItBu= (1,3-ditert-butyl)imidazol-2-ylidene], but instead, the reactionled to deprotonation from the imidazolium backbone of ItBu, forming the imidazolium salt with a silyl backbone at the C4position (3). We presumed that the reaction proceededthrough the generation of an ephemeral silylene. We subsequently preparedthe analogous germylene (4) and reacted it with IDipp[IDipp = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene], ItBu, and IDipp=CH2. Spectroscopic and crystallographicanalysis of these complexes revealed that, in all cases, there wasdeprotonation from the backbone and formation of zwitterionic products(5-7). When the hydrogen in the NHCbackbone was replaced with methyl groups such as IDipp(Me) (1,3-bis(2,6-diisopropylphenyl)-4,5-dimethylimidazol-2-ylidene),simple adduct formation occurred, exemplified by the isolation ofIDipp(Me)\& BULL;Ge(NSiMe3)(2)C10H6 (8).

}, issn = {0276-7333}, doi = {10.1021/acs.organomet.3c00167}, author = {Gour, Kritika and Pramanik, Debjit and Dash, Soumya Ranjan and Tothadi, Srinu and Vanka, Kumar and Sen, Sakya S.} } @article {48971, title = {Access to NHC-Boryl mono- and bis-selenide and utility as mild selenium transfer reagent including to the C-F bond}, journal = {Chemistry- a european journal}, volume = {30}, year = {2024}, month = {JAN }, type = {Article}, abstract = {

Reactions of 5-SIDipp \& sdot; BH3 (5-SIDipp=1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene) (1) with diphenyldiselenide provide access to 5-SIDipp-boryl mono- (5-SIDipp \& sdot; BH2SePh) (2) and bis-selenide (5-SIDipp \& sdot; BH(SePh)2) (3). The facile cleavage of the B-Se bond makes 2 a neutral source of selenium nucleophiles in substitutions reactions with benzyl bromides, and provide access to the corresponding selenoethers. The direct transformations of one of the C(sp2)-F bonds of C5F5N and C6F5CF3 to C-Se bonds have also been achieved by the use of 2 without employing transition-metal catalysts. While it was previously established that C6F6 could undergo complete defluoroselenation under harsh conditions, we successfully achieved partial defluorination of C6F6 by employing 2 as a mild selenide transfer reagent. During the formation of C-Se bonds through the cleavage of C-F bonds, the potential by-product NHC \& sdot; BH2F undergoes ring expansion of the NHC, leading to the formation of the six-membered diaazafluoroborinane (7). Access to NHC \& sdot; boryl mono- and bis-selenides from NHC \& sdot; BH3 has been achieved. The boryl mono selenide has been demonstrated to function as a selenium transfer reagent, enabling the synthesis of selenoethers from benzyl bromide. Additionally, it can also facilitate the conversion of the challenging aromatic C-F bond to a C-Se bond, resulting in concomitant ring expansion of NHC \& sdot; haloborane.image

}, keywords = {boron, C-F Bond Activation, N-Heterocyclic carbene, Ring expansion, Selenium}, issn = {0947-6539}, doi = {10.1002/chem.202302984}, author = {Kundu, Gargi and Amrutha, P. R. and Tothadi, Srinu and Sen, Sakya S.} } @article {49393, title = {Activation of carbon disulfide by a hypersilyl germylene}, journal = {Dalton Transactions}, volume = {53}, year = {2024}, month = {JUL}, type = {Article}, abstract = {

In this work, the insertion of CS2 into the Ge-Si bond of PhC(NtBu)2Ge-Si(SiMe3)3 (1) has been investigated, resulting in the formation of PhC(NtBu)2Ge-C( 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 S)-S-Si(SiMe3)3 (2). Interestingly, the addition of NHC to 2 allows the release of NHCCS2 with concomitant regeneration of 1. Addition of another equivalent of 1 or an analogous hypersilyl silylene, [PhC(NtBu)2Si-Si(SiMe3)3], to 2 led to the formation of compounds with a GeS (3) or a SiS (4) bond. In this work, the insertion of CS2 into the Ge-Si bond of PhC(NtBu)2Ge-Si(SiMe3)3 (1) has been investigated, resulting in the formation of PhC(NtBu)2Ge-C(S)-S-Si(SiMe3)3 (2).

}, issn = {1477-9226}, doi = {10.1039/d4dt01573h}, author = {Ajithkumar, V. S. and Khilari, Nripen and Ghanwat, Pratiksha B. and Venugopal, Geethu and Koley, Debasis and Sen, Sakya S.} }