@article {46086, title = {Stabilization of bis(chlorogermyliumylidene)s within bifunctional PNNP ligand frameworks and their reactivity studies}, journal = {Dalton Transactions}, volume = {48}, year = {2019}, month = {JUN }, pages = {7344-7351}, type = {Article}, abstract = {

The diiminodiphosphine (L-im) and diaminodiphosphines (l-NH and l-NMe) with a bifunctional PNNP ligand framework have been employed to host two [GeCl](+) units leading to the formation of bis(chlorogermyliumylidene) 1-3, respectively. The synthetic route involves a 1:2 stoichiometric reaction between the PNNP ligand and GeCl(2)dioxane and the subsequent addition of two equivalents of chloride abstracting agent. Compound 1 is unstable towards coordinating solvents and Lewis bases, resulting in the displacement of the GeCl unit and the formation of rearranged products 4 and 5. However, the diaminodiphosphine coordinated Ge(ii) bis(monocation)s 2 and 3 proved to be stable and revealed their electrophilic behaviour towards the Lewis bases studied.

}, issn = {1477-9226}, doi = {10.1039/c9dt00109c}, author = {Sahoo, Padmini and Raut, Ravindra K. and Maurya, Devesh and Kumar, Vikas and Rani, Pooja and Gonnade, Rajesh G. and Majumdar, Moumita} } @article {47587, title = {Intramolecularly double-donor-stabilized stannylene and its coordination towards Ag(I) and Au(I) centers}, journal = {Chemistry-An Asian Journal}, volume = {16}, year = {2021}, month = {AUG }, pages = {2118-2125}, type = {Article}, abstract = {The intramolecularly double-donor-stabilized stannylene 1 has been synthesized from the salt-metathesis reaction between two equivalents of lithium pyridine ene-amide L1 and SnCl2. Compound 1 exhibits dipolar behavior when reacted with B(C6F5)(3) leading to the zwitterionic compound 2. The reaction of 1 with one equivalent and 0.5 equivalent of AgOTf (OTf=trifluoromethane sulfonate) result in the formation of a stannylene-AgOTf complex 3 and a homoleptic distannylene-silver ionic complex 4, respectively. Analogous to complex 4, the gold(I) complex 5 has been synthesized from the reaction between two equivalents of 1 and 0.5 equivalent of AuCl.SMe2/Me3SiOTf. Complex 5 is the first example of homoleptic stannylene-Au(I) ionic complex among the very scarce reports on stannylene-gold(I) coordination complexes. All compounds have been structurally characterized using single crystal X-ray crystallography. Solution-state characterization have been performed using multinuclear NMR techniques. Detailed DFT calculations on the optimized geometries 1 o, 3 o-5 o reveal the change in sp- hybridization on the pyramidal Sn(II) center upon metal coordination and their bonding overlaps.}, keywords = {coordination, gold cation, hybridization, intramolecular donor, stannylene}, issn = {1861-4728}, doi = {10.1002/asia.202100523}, author = {Chibde, Purva and Raut, Ravindra K. and Kumar, Vikas and Deb, Rahul and Gonnade, Rajesh and Majumdar, Moumita} } @article {47714, title = {Stabilization of the elusive antimony(I) cation and its coordination complexes with transition metals}, journal = {Angewandte Chemie-International Edition}, volume = {60}, year = {2021}, month = {NOV}, pages = {25522-25529}, type = {Article}, abstract = {Upon stabilization by 5,6-bis(diisopropylphosphino)acenaphthene to form compound 1, the fugitive antimony (I) cation exhibited nucleophilic behavior towards coinage metals. Compound 1 was strategically synthesized at room temperature from SbCl3, the bis(phosphine), and trimethylsilyl trifluoromethanesulfonate taken in a 1:2:3 ratio, whereby the bis(phosphine) plays the dual role of a reductant and a supporting ligand. The generation of 1 involves two-electron oxidation of the ligand to form a P-P bonded diphosphonium dication. Compound 1 was separated from this dication to give both products in pure form in moderate yields. Despite the overall positive charge, the Sb-I site in 1 was found to bind to metal centers, forming complexes with Au-I, Ag-I and Cu-I. Compound 1 reduced Cu-II to Cu-I and formed a coordination complex with the resulting Cu-I species. The effects of the electron-rich bis(phosphine) and the constrained peri geometry in stabilizing and enhancing the nucleophilicity of 1 have been rationalized through computational studies.}, keywords = {antimony(I) cation, coordination modes, nucleophilicity, phosphine ligands, reduction}, issn = {1433-7851}, doi = {10.1002/anie.202111339}, author = {Kumar, Vikas and Gonnade, Rajesh G. and Yildiz, Cem B. and Majumdar, Moumita} } @article {48969, title = {Intramolecular donor-stabilized tetra-coordinated germanium(iv) di-cations and their Lewis acidic properties}, journal = {Chemical Science }, volume = {14}, year = {2023}, month = {DEC }, pages = {13755-13764}, type = {Article}, abstract = {

We report the first examples of intramolecular phosphine-stabilized tetra-coordinated germanium(iv) di-cationic compounds: [(L2Ge)-Ge-iPr][CF3SO3](2)3iPr and [(L2Ge)-Ge-Ph][CF3SO3](2)3Ph (L-iPr = 6-(diisopropylphosphanyl)-1,2-dihydroacenaphthylene-5-ide; L-Ph = 6-(diphenylphosphanyl)-1,2-dihydroacenaphthylene-5-ide). The step wise synthetic strategy involves the isolation of neutral and mono-cationic Ge(iv) precursors: [(L2GeCl)-Ge-iPr][X] (X = GeCl(3)1iPr, OTf 2iPr), [(L2GeCl2)-Ge-Ph] 1Ph and [(L2GeCl)-Ge-Ph][OTf] 2Ph. Both 3iPr and 3Ph exhibit constrained spiro-geometry. DFT studies reveal the dispersion of di-cationic charges over P-Ge-P sites. Anion or Lewis base binding occurs at the Ge site resulting in relaxed distorted trigonal bipyramidal/tetrahedral geometry. 3iPr and 3Ph activate the Si-H bond initially at the P-site. The hydride ultimately migrates to the Ge-site rapidly giving [(L2GeH)-Ge-Ph][CF3SO3] 3PhH, while sluggishly forming [(L2GeH)-Ge-iPr][CF3SO3] 3iPrH. Compounds 3iPr and 3Ph were tested as catalysts for the hydrosilylation of aromatic aldehydes. While catalytic hydrosilylation proceeded via the initial Et3Si-H bond activation in the case of 3iPr, compound 3Ph as a catalyst showed a masked Frustrated Lewis Pair (FLP) type reactivity in the catalytic cycle.

}, issn = {2041-6520}, doi = {10.1039/d3sc03717g}, author = {Peddi, Balakrishna and Khan, Souvik and Gonnade, Rajesh G. and Yildiz, Cem B. and Majumdar, Moumita} } @article {49139, title = {Zwitterionic tetrastanna(II) cyclic crown}, journal = {European Journal of Inorganic Chemistry}, volume = {26}, year = {2023}, month = {OCT }, type = {Article}, abstract = {

A 12-membered zwitterionic tetrastanna(II) cycle 1 having a crown ether-like topology has been isolated from the deprotonation of 1,1 \& PRIME;-methylenediimidazole (B) with two equivalents of Sn[N(SiMe3)(2)](2) (A). The solid-state structure and NMR analysis confirms the tetrastanna(II) cycle 1 to be comprised of two stannate(II) and two stannyliumylidene ion pairs in alternating positions of the heterocycle. Computational analysis shows greater nucleophilicity at the proximally located stannate(II) centers. Nonetheless, the tetrastanna(II) cycle 1 remains poorly reactive due to engagement of Sn-II lone pair electrons in intramolecular donor-acceptor interactions. Simple deprotonation reaction between Sn[N(SiMe3)(2)](2) (A) and N-(diisopropylphenyl)imidazole (C) in equimolar ratio has led to a stannylene 2, involving the formation of a Sn-C covalent bond with the anionic imidazol-2-yl carbon center along with the release of NH(SiMe3)(2). Compound 2 exists as a dimer, where the unsubstituted ring nitrogen atom coordinated intermolecularly to the other stannylene center.

}, keywords = {Deprotonation, Imidazole, Macrocycle, Sn-II cation, stannylene}, issn = {1434-1948}, doi = {10.1002/ejic.202300249}, author = {Sahoo, Padmini and Chibde, Purva and Das, Satyabrata and Banerjee, Subhrashis and Mali, Bhupendra P. and Vanka, Kumar and Gonnade, Rajesh G. and Yildiz, Cem. B. and Majumdar, Moumita} } @article {50085, title = {Smallest acyclic tricationic molecule containing a Bis(phosphine)-stabilized low-valent triantimony-based Unit}, journal = {Nature Communications}, volume = {17}, year = {2026}, month = {MAR}, pages = {2697}, type = {Article}, abstract = {

Element-element bonded multiply charged cationic species are well known as dimers or small cyclic oligomers in the condensed phase. However, the smallest acyclic version, a trinuclear unit possessing greater than a monocationic charge, has remained elusive. Here we introduce a bis(phosphine) supported low valent triantimony-based tricationic compound as a new entrant in this field. Structural elucidation and electronic understanding reveal a W-shaped tricationic unit comprising of a three-center four-electron sigma-bonded triantimony moiety that is terminally capped by bis(phosphine) ligands, with the central antimony atom having two lone pairs of electrons. The unique counter trianion [Sb(O)2(OTf)4]3- (OTf = CF3SO3) possesses reactive polar Sb delta+-O delta- bonds, the structure of which is determined from single crystal X-ray diffraction analysis. The ensemble of reactive molecular fragments found in this highly charged antimony-based compound makes it thermally unstable. Nonetheless, this fully characterized fleeting species shows a diverse reactivity profile, advancing the isolation of various novel antimony compounds, including the formation of a distinct low-valent antimony-cobalt carbonyl cluster.

}, doi = {10.1038/s41467-026-70910-5}, author = {Mukherjee, Nilanjana and Peerless, Benjamin and Nadurata, Vincent L. and Kumar, Vikas and Sangole, Mayur P. and Singh, Kirandeep and Wiedemann, Haakon T. A. and Kay, Christopher W. M. and Kruk, Robert and Weigend, Florian and Dehnen, Stefanie and Gonnade, Rajesh G. and Yildiz, Cem B. and Majumdar, Moumita} }