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Thiele's Hydrocarbons (THs) featuring a 9,10‐anthrylene core with switchable geometric and electronic configurations offer exciting possibilities in advanced functional materials. Despite significant advances in main group‐based diradicaloids in contemporary chemistry, main group THs containing an anthrylene cores have remained elusive, primarily due to the lack of straightforward synthetic strategies and the inherent high reactivity of these species. In this study, we utilize an anthracene‐based phosphine synthon to demonstrate, for the first time, a facile and high‐yielding synthetic strategy for robust P‐functionalized overcrowded ethylenes (OCEs) within the TH family. These OCEs feature a non‐symmetric environment, incorporating (thio) xanthyl and phosphaalkene termini. We systematically probe the electronic structures of these derivatives to illustrate the impact of the isolobal phosphaalkene motif on the quinoidal/diradicaloid character. Notably, the compounds exhibit dynamic redox behavior, leading to orthogonally twisted conformational changes upon oxidation, with a kinetically locked redox‐couple. [ABSTRACT FROM AUTHOR]

The stepwise reduction of the highly contorted truxene‐based triphosphaalkene 1 using KC8 led to the isolation of mono‐, di‐, and tri‐anionic species. The solid‐state molecular structures of mono‐ and diradical anionic species were elucidated by single crystal X‐ray diffractions, revealing elongated P−C bonds and a pronounced “indene” aromatization compared to the parent system. All three radical species displayed distinct Electron Paramagnetic Resonance (EPR) spectra, providing compelling evidence for the open‐shell electronic configuration of both the diradical and triradical species—an observation unprecedented in any previously reported phosphorous‐based anionic polyradicals. Mulliken spin density calculations revealed a dominant localization of radical spin on a single phosphorous atom in the monoanion. In the dianion, spin localization is observed on two phosphorous atoms (~34 % each), with a minor contribution from the third phosphorous (0.13 %), while the trianion demonstrates a uniform distribution of spin density (~30 %) across each phosphorous atom. [ABSTRACT FROM AUTHOR]

Owing to the strict hard/soft dichotomy between the lanthanoids and tellurium atoms, and the strong affinity of lanthanoid ions for high coordination numbers, low‐coordinate, monomeric lanthanoid tellurolate complexes have remained elusive as compared to the lanthanoid complexes with lighter group 16 elements (O, S, and Se). This makes the development of suitable ligand systems for low‐coordinate, monomeric lanthanoid tellurolate complexes an appealing endeavor. In a first report, a series of low‐coordinate, monomeric lanthanoid (Yb, Eu) tellurolate complexes were synthesized by utilizing hybrid organotellurolate ligands containing N‐donor pendant arms. The reaction of bis[2‐((dimethylamino)methyl)phenyl] ditelluride, 1 and 8,8′diquinolinyl ditelluride, 2 with Ln0 metals (Ln=Eu, Yb) resulted in the formation of monomeric complexes [LnII(TeR)2(Solv)2] [R=C6H4‐2‐CH2NMe2] [3: Ln=Eu, Solv=tetrahydrofuran; 4: Ln=Eu, Solv=acetonitrile; 5: Ln=Yb, Solv=tetrahydrofuran; 6: Ln=Yb, Solv=pyridine] and [EuII(TeNC9H6)2(Solv)n] (7: Solv=tetrahydrofuran, n=3; 8: Solv=1,2‐dimethoxyethane, n=2), respectively. Complexes 3–4 and 7–8 represent the first sets of examples of monomeric europium tellurolate complexes. The molecular structures of complexes 3–8 are validated by single–crystal X‐ray diffraction studies. The electronic structures of these complexes were investigated using Density Functional Theory (DFT) calculations, which revealed appreciable covalency between the tellurolate ligands and lanthanoids. [ABSTRACT FROM AUTHOR]

The metathesis reaction of aryltellurium chloride, ppyTeCl [ppy=2‐(2'‐pyridyl)phenyl] (5) with AgClO4 afforded Intramolecular Chalcogen Bonding (IChB)‐stabilized organotellurenyl cation [ppyTe] ⋅ ClO4 ([6] ⋅ ClO4). The reaction of [6] ⋅ ClO4 with K2PtCl4 in acetic acid resulted in the formation of platinum(II)‐based carboxylate‐bridged heterobimetallic complex [Pt(ppyTe)(μ‐OOCMe)Cl2], 7 containing an organotellurenyl cation as ligand. This is the first time a Pt(II) complex of an organotellurenyl cation donor‐acceptor ligand has been reported. Complex 7 was characterized by multi‐nuclear NMR spectroscopy (1H, 13C, and 125Te), FT‐IR spectroscopy, CHN analysis, and single‐crystal X‐ray diffraction studies. The single‐crystal X‐ray diffraction studies and DFT analysis infer that the Te center in 7 behaves as an ambiphilic ligand, accepting electrons from the N‐atom of the ppy moiety and the O‐atom of the carboxylate groups while simultaneously donating electrons to the Pt(II) center. The 2D‐fingerprint plots derived from the Hirshfeld surface analysis reveal multiple intermolecular interactions in the packing diagrams of complex 7. The natural charges accumulated on the atoms in complex 7 were calculated by Natural Population Analysis (NPA). In addition, the HOMO‐LUMO energy gap in 7 was calculated. [ABSTRACT FROM AUTHOR]

The oxidation reaction of L-tellurocystine, [Te2{CH2CH(NH3+)COO−}2] (4) with H2O2 in the presence of HBr resulted in the formation of cyclic, zwitterionic organotellurolate(IV) species, namely [Te−{CH2CH(NH3+)COO}(Br)3] (5). The H2O2 oxidation of Te-protected tellurocysteine derivatives [RTe{CH2CH(NH2)COOH}] [R = C6H5 (6) and 4-MeC6H4 (7)] in the presence of HCl resulted in the formation of chlorotellurane species [(C6H5)Te{CH2CH(NH3+)COOH}(Cl)2]Cl (8) and [(4-MeC6H5)Te{CH2CH(NH3+)COO}(Cl)]Cl (9), respectively. The oxidation reaction of diorganodiselenides R2Se2 [R = 4-MeC6H4 (10), R = 4-OMeC6H4 (11), R = 3,4-Me2C6H3 (12) and R = 2,4,6-Me3C6H2 (13)] with H2O2 afforded homoleptic diorganoselenones R2SeO2 [R = 4-MeC6H4 (14), R = 4-OMeC6H4 (15), R = 3,4-Me2C6H3 (16) and R = 2,4,6-Me3C6H2 (17)], respectively. The synthesized compounds were thoroughly characterized by multinuclear NMR (1H, 13C, 125Te/77Se), FT-IR spectroscopy, ESI-MS and elemental analysis. The molecular structures of the compounds were determined by single crystal X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

The discovery of the first isolable N-heterocyclic carbene in 1991 ushered in a new era in coordination chemistry. The remarkable bonding properties of carbenes have led to their rapid proliferation as auxiliary ligands for a wide range of transition metals and main group elements. In the case of group 15, while carbene-stabilized nitrogen and phosphorus compounds are extensively studied, the scope of research has shrunk significantly from arsenic to bismuth. This is essentially attributed to the decrease in stability of the C–E bond upon descending the group. Even so, modulating the carbene backbone or introducing alternative synthetic strategies not only alleviates the stability issues but also offers promising results in terms of the bonding and reactivities of these compounds. The purpose of the present perspective is to provide a comprehensive overview of the origins and development of carbene chemistry of arsenic, antimony, and bismuth, as well as to highlight the future prospects of this field. [ABSTRACT FROM AUTHOR]

The structural characterisation of bis(8-sulfanylquinolinium) hexachloridostannate(iv) (2) is reported and the variable reaction behaviour of this compound in different solvents has been explored. In particular, attempted recrystallization of 2 from chloroform and dichloromethane affords two polymorphs of cis -dichloridobis(8-quinolinethiolato)tin(iv), 3m and 3t , respectively. Attempted recrystallization of 2 from methanol gives crystals of 8,8′-dithiodiquinolinium hexachloridostannate(iv) 4. When 2 is dissolved in dimethyl sulfoxide in the presence of air, it undergoes oxidation to afford diquinolinyl-8,8′-disulfide 5. The molecular structures of the isolated compounds 2 – 4 are unambiguously authenticated by single crystal X-ray diffraction studies. The electronic structure properties of all the isolated compounds 2 – 4 are thoroughly studied by DFT calculations. Bis(8-sulfanylquinolinium) hexachloridostannate(IV) undergoes variable reaction behaviour in different solvents to form cis -dichloridobis(8-quinolinethiolato)tin(IV), 8,8′-dithiodiquinolinium hexachloridostannate(IV), and diquinolinyl-8,8′-disulfide. [ABSTRACT FROM AUTHOR]

A simple methodology for the synthesis of heteroleptic diorganotelluride [2,6‐(Me2NCH2)2C6H3]TenBu (1) and homoleptic diorganotelluride [2,6‐(Me2NCH2)2C6H3]2Te (2) is reported. The halogenation reactions of diorganotelluride 1 are studied. In particular, the reaction of 1 with Br2 resulted in the isolation of a monoorgano dibromotelluronium(IV) cation, namely [2,6‐(Me2NCH2)2C6H3TeBr2]·Br3 ([3]·Br3). The reaction of [3]·Br3 with K2PdCl4 afforded a monoorgano mixed dihalotelluronium(IV) cation, [2,6‐(Me2NCH2)2C6H3TeClBr]·PdBr4 ([4]·PdBr4). When diorganotelluride 1 was treated with I2, the reaction afforded the tellurenium(II) cation, [2,6‐(Me2NCH2)2C6H3Te]·I2·I3 ([5]·I2·I3). The reaction of 1 with HgCl2 resulted in the isolation of dimeric diorganoditelluroxonium(IV) cation, [2,6‐(Me2NCH2)2C6H3Te(µ‐O)]2·Hg2Cl6 ([6]·Hg2Cl6). A similar diorganoditelluroxonium(IV) cation, namely [2,6‐(Me2NCH2)2C6H3Te(µ‐O)]2·2Br ([6]·2Br) was also obtained by the reaction of 1 with Br2 and NaOH. The crystallographic studies suggest that for each compound, both the N atoms from the pendant arms make strong Intramolecular Chalcogen Bonding (IChB) interactions with the Te center(s). The presence of a strong N→Te IChB interaction in the synthesized compounds was further validated by DFT calculations. [ABSTRACT FROM AUTHOR]

In the title salt, di-μ-oxido-bis­{2,6-bis­[(di­methyl­amino)­meth­yl]phenyl-κC¹}tellurium(­IV) bis[tri­chlorido­(dimethyl sulfoxide-κS)platinate(II)], (C24H38N4O2Te2)[PdCl3(C2H6OS)]2, which crystallizes in the triclinic space group P1̅, each Te atom is in a distorted five-coordinated TeO2N2C square-pyramidal geometry (τ values of 0.026 and 0.001) with the C atoms of the phenyl rings occupying the apical positions. The phenyl rings in the [C24H38N4O2Te2]2+ cation are in a cis arrangement to enable this species to participate in Te...Cl cation–anion inter­actions. There are also C—H...O inter­actions involving the dimethyl sulfoxide ligands and numerous cation–anion and anion–anion C—H...Cl inter­actions, which link the ions into a complex three-dimensional array. [ABSTRACT FROM AUTHOR]

The intramolecularly coordinated homoleptic diorgano selenide bis{2,6‐bis[(dimethylamino)methyl]phenyl} selenide, C24H38N4Se or R2Se, where R is 2,6‐(Me2NCH2)2C6H3, 14, was synthesized and its ligation reactions with PdII and HgII precursors were explored. The reaction of 14 with SO2Cl2 and K2PdCl4 resulted in the formation of the meta C—H‐activated dipalladated complex {μ‐2,2′‐bis[(dimethylamino)methyl]‐4,4′‐bis[(dimethylazaniumyl)methyl]‐3,3′‐selanediyldiphenyl‐κ4C1,N2:C1′,N2′}bis[dichloridopalladium(II)], [Pd2Cl4(C24H38N4Se)] or [{R(H)PdCl2}2Se], 15. On the other hand, when ligand 14 was reacted with HgCl2, the reaction afforded a dimercurated selenolate complex, {μ‐bis{2,6‐bis[(dimethylamino)methyl]benzeneselanolato‐κ4N2,Se:Se,N6}‐μ‐chlorido‐bis[chloridomercury(II)], [Hg2(C12H19N2Se)Cl3] or RSeHg2Cl3, 16, where two HgII ions are bridged by selenolate and chloride ligands. In palladium complex 15, there are two molecules located on crystallographic twofold axes and within each molecule the Pd moieties are related by symmetry, but there are still two independent Pd centers. Mercury complex 16 results from the cleavage of one of the Se—C bonds to form a bifurcated SeHg2 moiety with the formal charge on the Se atom being −1. In addition, one of the Cl ligands bridges the two Hg atoms and there are two terminal Hg—Cl bonds. Each Hg atom is in a distorted environment which can be best described as a T‐shaped base with the bridging Cl atom in an apical position, with several angles close to 90° and with one angle much larger and closer to 180°. [ABSTRACT FROM AUTHOR]

By the transmetallation of ppyHgCl [ppy = 2‐(2'‐pyridyl)phenyl] (1) with SnCl4 and SbCl3, the synthesis of the monoorgano main group halides, [ppySnCl3(H2O)]·2(0.5diox) (diox = 1,4‐dioxane) [2(H2O)]·2(0.5diox) and [ppySbCl2] (3) was achieved. The reaction of 1 with BiCl3 does not give the analogous monoorganobismuth dichloride. Instead, it results in the formation of [(ppy)2Bi]+·[ppyBiCl3]– (4). Reactions of (ppy)2Te and (ppyTe)2 with SO2Cl2 and Br2 result in the formation of ppyTeCl (5) and ppyTeBr (6) respectively. All the synthesized compounds were characterized by multi‐nuclear NMR spectroscopy (1H, 13C, 119Sn, and 125Te), FT‐IR spectroscopy, ESI‐MS, CHN analysis, and single‐crystal X‐ray diffraction studies. The molecular structures of 2–6 reveal strong intramolecular coordination of the N‐atoms of the pendant arms with the main group element centers. DFT calculations; including Natural Bond Order (NBO), Electron Localization Function (ELF), Electrostatic Surface Potential (ESP) and Atoms in Molecules (AIM) infer that the stability of 2–6 relies on the σ‐hole participation of the element center with the N‐lone pair of the pyridyl arm. [ABSTRACT FROM AUTHOR]

The stoichiometrically controlled alkaline hydrolysis of 4, (ppy)TeCl3, [ppy = 2-(2′-pyridyl)phenyl] afforded the partially hydrolyzed μ-oxo-bridged dinuclear telluroxane 5, [(ppyTeCl2)2(μ-O)] and a novel example of an Intramolecular Chalcogen Bonding (IChB) stabilized, monomeric organotellurinic acid 6, (ppy)Te(O)OH. The oxidation of diaryl ditelluride 7, (ppyTe)2 using H2O2 resulted in the isolation of μ-oxo-bridged dimethyl ester 8, [(ppy)Te(O)(OH)(OMe)]2(O). The molecular structures of 4–6 and 8 are unambiguously authenticated by single crystal X-ray diffraction studies. The electronic structure of monomeric tellurinic acid 6 is investigated using DFT calculations. The Natural Bond Order (NBO) analysis, in corroboration with Atoms in Molecules (AIM) analysis reveals that tellurinic acid 6 is stabilized by σ-hole participation of the tellurium atom with the pyridyl N-atom resulting in strong electrostatic interactions between the N and Te atoms. [ABSTRACT FROM AUTHOR]

The synthesis of a series of palladium(II) complexes of unsymmetrical, hybrid selenoether and telluroether ligands is reported. While the reaction of Pd(II) precursors with symmetrical telluroether ligands containing two coordinating groups results in cleavage of Te–C bond, no such labilisation is observed using unsymmetrical ligands containing one coordinating group. Two novel unsymmetrical selenoether ligands namely, N,N -dimethyl-2-(o -tolylselanyl)aniline (10) and 2-((2,6-dimethylphenyl)selanyl)- N,N -dimethylaniline (11) were synthesized from N,N -dimethylbenzylamine via the ortho -lithiation route. When ligands 10 and 11 were treated with Pd(COD)Cl 2 (COD = 1,5-cyclooctadiene), the reaction afforded novel Pd(II) complexes of the form Pd(2-NMe 2 CH 2 C 6 H 4)(R)SeCl 2 , where R = 2-MeC 6 H 4 (16) and 2,6-MeC 6 H 3 (17) respectively. Similarly, when unsymmetrical telluroether ligands, N,N -dimethyl-2-(phenyltellanyl)aniline (12) , N,N -dimethyl-2-(o-tolyltellanyl)aniline (13), 2-((2,6-dimethylphenyl)tellanyl)- N,N -dimethylaniline (14) and 2-((2,6-diisopropylphenyl)tellanyl)- N,N -dimethylaniline (15), which contain one coordinating group with an sp 3 N-donor atom, were treated with Pd(COD)Cl 2 , the palladium telluroether complexes of the form Pd(2-NMe 2 CH 2 C 6 H 4)(R)TeCl 2 , where R = C 6 H 5 (18), 2-MeC 6 H 4 (19), 2,6-MeC 6 H 3 (20) and 2,6- i PrC 6 H 3 (21) respectively were obtained. The selenoether complexes 16 and 17 and telluroether complexes 18 , 20 and 21 were characterized by single crystal X-ray diffraction studies. In the asymmetric unit of complex 18 , two molecules are present and due to the presence of weak, intermolecular Te⋯Cl interactions, the two molecules exist as symmetrically related dimer. The N-donor substituents, which were involved in intramolecular chalcogen bonding (IChB) with the chalcogen atoms in the free ligand, made six-membered chelating rings in the complexes. Again, when bis(2-phenylazophenyl- C,N ′)selenide 22 was treated with Pd(COD)Cl 2 , it afforded ortho C–H bond activated cyclopalladated complex 24. However, when bis(2-phenylazophenyl- C,N ′)telluride 23 was treated with Pd(COD)Cl 2 , due to strong IChB from two N-donor substituents, the reaction afforded cleaved product, [2-(phenylazo)phenyl-C,N′]tellurenyl chloride, 25. All the metal complexes exhibited significant downfield chemical shifts in 77Se/125Te NMR spectra as compared to the corresponding free ligands. The downfield shifts in the 77Se/125Te NMR signal in the complexes might be attributed to the coordination of the chalcogen atoms to the electropositive Pd(II) center. [ABSTRACT FROM AUTHOR]

Intramolecularly coordinated homoleptic diorganotelluride L2Te (6) [where L = 2,6-(Me2NCH2)2C6H3] was synthesized and its reactions with Pd(II) and Hg(II) precursors were explored. The reaction of 6 with SO2Cl2 and K2PdCl4 resulted in the formation of the first example of a Pd(II) complex, LTePdCl3 (7), with any organotellurenium cation (LTe+) as a ligand. When diorganotelluride 6 was reacted with HgCl2, the reaction afforded the tellurenium cation [LTe]2+[Hg2Cl4]2− (8). The reaction of 6 with [(PhCN)2PdCl2] afforded the Pd(II)–telluroether complex L2TePdCl2 (9). Diorganotelluride 6 and complexes (7–9) were characterized by single-crystal X-ray diffraction studies. The crystallographic studies suggested that in complex 7, the Te(II) center was 'ambiphilic' in nature in the sense that while Te(II) acted as a donor to the Pd(II) ion, at the same time, it accepted electrons from the N-donor side arms via secondary bonding interactions. The donation of electrons from Te(II) to Pd(II) in complex 7 was further substantiated by Natural Bond Order (NBO) analysis. [ABSTRACT FROM AUTHOR]

The oxidation reaction of unsymmetrical diorganotellurides, namely, bis[2-{(dimethylamino)methyl}aryl]tellurides [aryl = phenyl (6), 2-methylphenyl (7), 2,6-dimethylphenyl (8) and 2,6-diisopropylphenyl (9)] with meta-chloroperbenzoic acid afforded the first examples of tetraorganoditelluronic acids, [RR′Te(μ-O)(OH)2]2, where R = 2-NMe2CH2C6H4, R′ = C6H5 (10), 2-MeC6H4 (11), 2,6-MeC6H3 (12) and 2,6-iPrC6H3 (13). The structures of tetraorganoditelluronic acids 10–13 were authenticated by single crystal X-ray diffraction studies. From the molecular structures of 10–13, it was observed that the sp3 N-donor atoms, which were initially involved in intramolecular Te…N bonding interactions in diorganotellurides 6–9, did not interact with the tellurium atoms in tetraorganoditelluronic acids 10–13. The 125Te chemical shifts for 10–13 were considerably downfield shifted as compared with the values observed for the corresponding tellurides 6–9. The relative stabilities of the tetraorganoditelluronic acids 10–13 with respect to their lighter analogues (S and Se) have been assessed using DFT calculations. [ABSTRACT FROM AUTHOR]

The oxidation reaction of unsymmetrical diorganotellurides, namely, bis[2-{(dimethylamino)methyl}aryl]tellurides [aryl = phenyl (6), 2-methylphenyl (7), 2,6-dimethylphenyl (8) and 2,6-diisopropylphenyl (9)] with meta-chloroperbenzoic acid afforded the first examples of tetraorganoditelluronic acids, [RR′Te(μ-O)(OH)2]2, where R = 2-NMe2CH2C6H4, R′ = C6H5 (10), 2-MeC6H4 (11), 2,6-MeC6H3 (12) and 2,6-iPrC6H3 (13). The structures of tetraorganoditelluronic acids 10–13 were authenticated by single crystal X-ray diffraction studies. From the molecular structures of 10–13, it was observed that the sp3 N-donor atoms, which were initially involved in intramolecular Te…N bonding interactions in diorganotellurides 6–9, did not interact with the tellurium atoms in tetraorganoditelluronic acids 10–13. The 125Te chemical shifts for 10–13 were considerably downfield shifted as compared with the values observed for the corresponding tellurides 6–9. The relative stabilities of the tetraorganoditelluronic acids 10–13 with respect to their lighter analogues (S and Se) have been assessed using DFT calculations. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • New NNN- and CNC type N-hetrocyclic nitrenium ions (NHN) within tridentate pincer scaffold are reported. • The Natural Bond Order (NBO) calculations and Atoms in Molecules (AIM) analyses on the metal complexes adequately substantiate the presence of interaction between triazolium N with metal centre. • Synthesis of two new selone based OSeO type pincer ligands is reported. Abstract The synthesis of three new NNN- and CNC type N-heterocyclic nitrenium (NHN) ion based pincer ligands is reported from 1,3-di-(2′-bromoethyl)-triazolium bromide (5). The reaction of 5 with ammonium hexafluorophosphate followed by two equivalent of pyrrolidine/diethylamine afforded NHN ions (10a and 10b). The reaction of 5 with N-butylbenzimidazole (6) afforded nitrenium ion 7 , where the chelating arms have benzimidazole based carbene carbons. In an attempt to synthesize hybrid NHN ligand containing soft tellurium donor in the chelating arm, 1-(2′-bromoethyl)-benzotriazole was first reacted with in situ generated NaTePh to afford tellurated benzotriazol (13). However, when compound 13 was treated with methyl iodide, an unexpected methylation underwent at tellurium center to afford compound 14. Reaction of 7 with Hg(OAc) 2 and 10a with CuI afforded complexes 8 and 11 respectively. Both these complexes are characterized by NMR (1H, 13C), HRMS and CHN analysis. The Natural Bond Order (NBO) calculations and Atoms in Molecules (AIM) analyses sufficiently substantiate the presence of interaction between triazolium N atom with metal centre. The reaction of N,N′-disubstituted benzimidazoles, 17a – 17b with in situ generated Na 2 Se 2 in the presence of potassium tert -butoxide at room temperature afforded two novel benzimidazoline-2-chalcogenones (18a and 18b). Nitrenium ion (10a – 10b), tellurated benzotriazole (13 and 14) and selone 18a are authenticated by single crystal X-ray diffraction studies. [ABSTRACT FROM AUTHOR]

Selones, since their first report in 1963, have attracted significant interest with respect to their bonding, structure and more importantly as an ancillary ligand for complexation with various metals. Starting as an analogue of N-heterocyclic carbene (NHC), selones are considered as promising molecules in chemistry with numerous applications in various important processes. Herein, a brief overview of selone, its genesis and relevance in contemporary chemistry is given, particularly focusing on its syntheses, reactivity and applications. [ABSTRACT FROM AUTHOR]

Two novel hypervalent selenium(IV) compounds stabilized by intramolecular interactions, namely 6‐phenyl‐6,7‐dihydro‐5H‐2,3‐dioxa‐2aλ4‐selenacyclopenta[hi]indene, C14H12O2Se, 14, and 5‐phenyl‐5,6‐dihydro‐4H‐benzo[c][1,2]oxaselenole‐7‐carbaldehyde, C14H12OSe2, 15, have been synthesized by the reaction of 2‐chloro‐1‐formyl‐3‐(hydroxymethylene)cyclohexene with in‐situ‐generated disodium diselenide (Na2Se2). The title compounds were characterized by FT–IR spectroscopy, ESI–MS, and single‐crystal X‐ray diffraction studies. For 14, there is whole‐molecule disorder, with occupancies of 0.605 (10) and 0.395 (10), a double bond between C and Se, and the five‐membered selenopentalene rings are coplanar. The packing is stabilized by π–π stacking interactions involving one of the five‐membered Se/C/C/C/O rings [centroid–centroid (Cg...Cg) distance = 3.6472 (18) Å and slippage = 1.361 Å], as well as C—H...π interactions involving a C—H group and the phenyl ring. In addition, there are bifurcated C—H...Se,O interactions which link the molecules into ribbons in the c direction. For 15, the C—Se bond lengths are longer than those of 14. The two five‐membered rings are coplanar. There are no π–π or C—H...π interactions; however, molecules are linked by C—H...O interactions into centrosymmetric dimers, with graph‐set notation R22(16). In the structures of two chalcogenapentalene derivatives, 6‐phenyl‐6,7‐dihydro‐5H‐2,3‐dioxa‐2aλ4‐selenacyclopenta[hi]indene and 5‐phenyl‐5,6‐dihydro‐4H‐benzo[c][1,2]oxaselenole‐7‐carbaldehyde, the former is stabilized by Se—O bonds, while in the latter, there is both an Se—Se bond and an Se...O interaction, which helps in the stabilization of the structure. [ABSTRACT FROM AUTHOR]

A convenient approach for the synthesis of alicyclic selenospirocycles, 24 and 25, stabilized by intramolecular chalcogen bonding (IChB) is reported by the reaction of 5‐alkyl‐2‐chloro‐1‐formyl‐3‐hydroxymethylenecyclohexene derivatives {alkyl=H (22), Me (23)} with in situ generated disodium diselenide (Na2Se2). However, when 2‐chloro‐1‐formyl‐3‐hydroxymethylenecyclohexene, 22 is condensed with aniline or 4‐methoxyaniline and the resulting Schiff bases 26 and 27 are subjected to identical reactions, the Schiff bases undergo cyclisation to afford brightly colored, fused 1,6‐diaza‐6a‐selenapentalene derivatives 28–29, instead of the expected selenospirocycles. The aromatic nucleophilic substitution (SNAr) reaction of N‐(2‐bromo‐3‐nitrobenzyl)naphthylamine, 33 with nBuSeLi affords N‐[2‐(butylselanyl)‐3‐nitrobenzyl]naphthylamine, 34. The bromination of 34 results in the formation of cyclic isoselenazolines, 35. Selenospirocycles 24 and 25, 1,6‐diaza‐6a‐selenapentalenes 28 and 29 and isoselenazoline 35 are authenticated by single‐crystal X‐ray diffraction studies. Compounds 24, 25 and 35 are stabilized by intramolecular secondary interactions. The reaction of 5‐alkyl‐2‐chloro‐1‐formyl‐3‐hydroxymethylenecyclohexene derivatives (alkyl=H, Me) with in situ generated disodium diselenide (Na2Se2) affords alicyclic selenospirocycles. However, a similar reaction of the Schiff base derivatives of 2‐chloro‐1‐formyl‐3‐hydroxymethylenecyclohexene with Na2Se2 leads to the formation of highly colored azapentalenes. The attempted synthesis of selenospirocycle from N‐[2‐(butylselanyl)‐3‐nitrobenzyl]naphthylamine results in the formation of isoselenazolines. [ABSTRACT FROM AUTHOR]

• A series of novel Ru and Os complexes of the bidentate ligand, N,N′-bis(2-pyridyl)benzene-1,2-diamine is reported. • The electronic structures of the complexes and their accessible oxidized and reduced forms were experimentally studied. • The experimental observations are validated by DFT and TD-DFT calculations. The synthesis of Ru and Os complexes of the ligand, N,N′-bis(2-pyridyl)benzene-1,2-diamine namely, [RuIII(acac) 2 (Py-bqdi)], (9), [RuII(Ph-trpy)(Py-bqdi)Cl], (10) and [OsII(bpy) 2 (Py-bqdi)](ClO 4), (11 ClO 4) [where Py-bqdi = N,N′-dipyridyl- o -benzoquinonediimine, acac = 2,4-pentanedionate, Ph-trpy = 4′-phenyl-2,2′:6′,2″-terpyridine, bpy = 2,2′-bipyridine] is reported. The molecular structures of complexes 9 - 11 ClO 4 are authenticated by single crystal X-ray diffraction studies. The electronic structural properties of the complexes, in particular, the accessible oxidized/reduced forms of the complexes, are examined by using an array of analytical techniques (magnetic resonance, UV–Vis-NIR spectroscopy and electrochemistry). Comprehensive Density Functional Theory (DFT) calculations have also been carried out to provide additional support to the experimental work. [ABSTRACT FROM AUTHOR]

In the title salt, di-μ-oxido-bis-{2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κ C 1 }tellurium(-IV) bis[tri-chlorido-(dimethyl sulfoxide-κ S )platinate(II)], (C 24 H 38 N 4 O 2 Te 2 )[PdCl 3 (C 2 H 6 OS)] 2 , which crystallizes in the triclinic space group P , each Te atom is in a distorted five-coordinated TeO 2 N 2 C square-pyramidal geometry (τ values of 0.026 and 0.001) with the C atoms of the phenyl rings occupying the apical positions. The phenyl rings in the [C 24 H 38 N 4 O 2 Te 2 ] 2+ cation are in a cis arrangement to enable this species to participate in Te⋯Cl cation-anion inter-actions. There are also C-H⋯O inter-actions involving the dimethyl sulfoxide ligands and numerous cation-anion and anion-anion C-H⋯Cl inter-actions, which link the ions into a complex three-dimensional array., (© Gupta et al. 2020.)

The oxidation reaction of unsymmetrical diorganotellurides, namely, bis[2-{(dimethylamino)methyl}aryl]tellurides [aryl = phenyl (6), 2-methylphenyl (7), 2,6-dimethylphenyl (8) and 2,6-diisopropylphenyl (9)] with meta-chloroperbenzoic acid afforded the first examples of tetraorganoditelluronic acids, [RR'Te(μ-O)(OH) 2 ] 2 , where R = 2-NMe 2 CH 2 C 6 H 4 , R' = C 6 H 5 (10), 2-MeC 6 H 4 (11), 2,6-MeC 6 H 3 (12) and 2,6- i PrC 6 H 3 (13). The structures of tetraorganoditelluronic acids 10-13 were authenticated by single crystal X-ray diffraction studies. From the molecular structures of 10-13, it was observed that the sp 3 N-donor atoms, which were initially involved in intramolecular TeN bonding interactions in diorganotellurides 6-9, did not interact with the tellurium atoms in tetraorganoditelluronic acids 10-13. The 125 Te chemical shifts for 10-13 were considerably downfield shifted as compared with the values observed for the corresponding tellurides 6-9. The relative stabilities of the tetraorganoditelluronic acids 10-13 with respect to their lighter analogues (S and Se) have been assessed using DFT calculations.