Simple Adducts Research Articles

T-cell activation by transitory neo-antigens derived from distinct microbial pathways

T cells discriminate between foreign and host molecules by recognizing distinct microbial molecules, predominantly peptides and lipids. Riboflavin precursors found in many bacteria and yeast also selectively activate mucosal-associated invariant T (MAIT) cells, an abundant population of innate-like T cells in humans. However, the genesis of these small organic molecules and their mode of presentation to MAIT cells by the major histocompatibility complex (MHC)-related protein MR1 (ref. 8) are not well understood. Here we show that MAIT-cell activation requires key genes encoding enzymes that form 5-amino-6-d-ribitylaminouracil (5-A-RU), an early intermediate in bacterial riboflavin synthesis. Although 5-A-RU does not bind MR1 or activate MAIT cells directly, it does form potent MAIT-activating antigens via non-enzymatic reactions with small molecules, such as glyoxal and methylglyoxal, which are derived from other metabolic pathways. The MAIT antigens formed by the reactions between 5-A-RU and glyoxal/methylglyoxal were simple adducts, 5-(2-oxoethylideneamino)-6-D-ribitylaminouracil (5-OE-RU) and 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil (5-OP-RU), respectively, which bound to MR1 as shown by crystal structures of MAIT TCR ternary complexes. Although 5-OP-RU and 5-OE-RU are unstable intermediates, they became trapped by MR1 as reversible covalent Schiff base complexes. Mass spectra supported the capture by MR1 of 5-OP-RU and 5-OE-RU from bacterial cultures that activate MAIT cells, but not from non-activating bacteria, indicating that these MAIT antigens are present in a range of microbes. Thus, MR1 is able to capture, stabilize and present chemically unstable pyrimidine intermediates, which otherwise convert to lumazines, as potent antigens to MAIT cells. These pyrimidine adducts are microbial signatures for MAIT-cell immunosurveillance.

Sensitivity and Selectivity of Switchable Reagent Ion Soft Chemical Ionization Mass Spectrometry for the Detection of Picric Acid

We have investigated the reactions of NO(+), H3O(+), O2(+), and Kr(+) with picric acid (2,4,6 trinitrophenol, C6H3N3O7, PiA) using a time-of-flight mass spectrometer with a switchable reagent ion source. NO(+) forms a simple adduct ion PiA·NO(+), while H3O(+) reacts with PiA via nondissociative proton transfer to form PiAH(+). In contrast, both O2(+) and Kr(+) react with PiA by nondissociative charge transfer to produce PiA(+). For Kr(+), we also observe dissociation of PiA, producing NO2(+) with a branching percentage of approximately 40%. For the reagent ions H3O(+) and O2(+) (and operating the drift tube with normal laboratory air), we find that the intensities of the PiAH(+) and PiA(+) ions both exhibit a peak at a given drift-tube voltage (which is humidity dependent). This unusual behavior implies a peak in the detection sensitivity of PiA as a function of the drift-tube voltage (and hence E/N). Aided by electronic-structure calculations and our previous studies of trinitrotoluene and trinitrobenzene, we provide a possible explanation for the observed peak in the detection sensitivity of PiA.

A tale of hydrogen abstraction, initially detectedviaX-ray diffraction

Reaction of a bis-tetrazinyl pyridine pincer ligand, btzp, with a vanadium(III) reagent gives not a simple adduct but dichlorido{3-methyl-6-[6-(6-methyl-1,2,4,5-tetrazin-3-yl-κN(2))pyridin-2-yl-κN]-1,4-dihydro-1,2,4,5-tetrazin-1-yl-κN(1)}oxidovanadium(IV) acetonitrile 2.5-solvate, [V(C11H10N9)Cl2O]·2.5CH3CN, a species which X-ray diffraction reveals to have one H atom added to one of the two tetrazinyl rings. This H atom was first revealed by a short intermolecular N...Cl contact in the unit cell and subsequently established, from difference maps, to be associated with a hydrogen bond. One chloride ligand has also been replaced by an oxide ligand in this synthetic reaction. This formula for the complex, [V(Hbtzp)Cl2O], leaves open the question of both ligand oxidation state and spin state. A computational study of all isomeric locations of the H atom shows the similarity of their energies, which is subject to perturbation by intermolecular hydrogen bonding found in X-ray work on the solid state. These density functional calculations reveal that the isomer with the H atom located as found in the solid state contains a neutral radical Hbtzp ligand and tetravalent d(1) V center, but that these two unpaired electrons are more stable as an open-shell singlet and hence antiferromagnetically coupled.

Ene-thiol reaction of C3-vinylated chlorophyll derivatives in the presence of oxygen: synthesis of C3-formyl-chlorins under mild conditions

Reactions of thiol with the C 3-vinyl group of various chlorophyll (Chl) derivatives were examined. The reactions resemble thiol-olefin co-oxidation, except that the vinyl C = C double bond was cleaved to afford a formyl group without any transition metal catalyst, and that the simple anti-Markovnikov adduct of thiol to olefin was obtained as a minor product. Peripheral substituents of Chl derivatives little affected the reaction, while the central metal atom of the chlorin macrocycle influenced the composition of the products. Oxygen and acid dissolved in the reaction mixture can facilitate the oxidation. Sufficiently mild conditions in this regioselective oxidation at the C 31-position are significant in bioorganic chemistry.

The effect of substituents of the 1,10-phenanthroline ligand on the nature of diorgnotin(IV) complexes formation

The adduct formation between dimethyl- and dibuthyltin diisothiocyanate and 1,10-phenanthroline and 2,9-dimethyl-1,10-phenanthroline were investigated. It was found that the reaction of R2Sn(NCS)2 (R = Me, n-Bu) with 1,10-phenanthroline in a 1:1 M ratio led to the formation of simple adducts of [Me2Sn(NCS)2(phen)]·CH3CN (1) and [Bu2Sn(NCS)2(phen)] (2), for R = Me and R = n-Bu, respectively. However, the reaction of 2,9-dimethyl-1,10-phenanthroline with R2Sn(NCS)2 (R = Me, n-Bu), instead of adducts, resulted in the formation of an organostannate salt, (C14H13N2)2[Me2Sn(NCS)4] (3), and dimeric stannoxane, [Me2(NCS)SnOSnMe2OCH3]2 (4), for R = Me and (C14H13N2)NCS (5), and [Bu2(NCS)SnOSnR2OBu]2 (6), for R = n-Bu. Single crystal X-ray structural analyses were carried out for complexes 1, 3, 4, and 5. The crystal structures results of 1, 3, 4, and 5 along with the 1H, 13C and 119Sn NMR and IR spectroscopic measurements of all the products are used to discuss the effect of the substituent of 1,10-phenanthroline on complex formation. The results show that the central tin atom of the stannate salt (3) is not bonded to the two N donor atoms of the ligand species, and the moderately bulky substituent at the 2 and 9 positions of 1,10-phenanthroline ligand exerts a profound influence on the nature of the complexes and their formation.

Reactivity Study of Imino-N-Heterocyclic Carbene Palladium(II) Methyl Complexes

Neutral and cationic palladium(II) complexes containing three different heteroditopic bis(aryl)-substituted imino-N-heterocyclic carbene ligands have been synthesized and structurally characterized. Modifications made to the substituent at the iminic carbon allow for independent tuning of the steric and electronic environment around the metal center. The nature of this substituent profoundly affects the thermal stability of the neutral palladium complexes. While the tert-butyl derivative decomposes at 60 °C over a period of 24 h to give the corresponding 1-mesityl-2-methyl-1H-imidazole and the corresponding imidoyl chloride as the major products, the phenyl and methyl analogues show no sign of decomposition. Likewise, the corresponding cationic complexes of all three carbene derivatives are stable under the same conditions, with no evidence of decomposition. While inactive for ethylene polymerization, these palladium methyl complexes react with CO and isocyanides to form a variety of products, including structurally characterized simple adducts and single and multiple insertion products.

Activation of X–H Bonds (X = N, P, O, S) with SCS Pincer Palladium Complexes: A Theoretical Study

AbstractActivation of X–H bonds with SCS pincer palladium complexes featuring methanediide and indenediide backbones was studied by DFT calculations. Me2NH, Me2PH, MeOH, MeSH, PhOH, and PhSH were chosen as model substrates. Different products were considered for these addition reactions: simple adduct (X coordination), 1,2‐addition across the Pd–C and Pd–S bonds, 1,3‐addition (if possible), as well as oxidative addition at Pd. For the methanediide system, 1,2‐PdC adducts were predicted to be the most favored activation products. For the indenediide system, 1,3‐PdC and 1,2‐PdC additions are conceivable. This theoretical study suggests that methanediide and indenediide Pd complexes may be interesting candidates for catalytic transformations involving X–H bond activation, typically hydrofunctionalization reactions.

Neutral mononuclear and dinuclear complexes of gold(I) featuring azole ligands: Synthesis, structure and cytotoxicity

The aim of this work was to extend the small library of existing compounds of gold(I) that contain pentafluorophenyl and thiazole ligands and to determine the biological activity of such compounds against a well-known cancer cell line. Seven mono and dinuclear new compounds that contain imidazole, thiazole and tetrazole rings were isolated and characterised. Three of the crystal structures determined indicated Au…Au interactions between constituent complex molecules. A simple adduct, [Au(C6F5)(N-methyl-imidazole)], exhibits a relatively high anti-tumour specificity indicating the viability of selected phosphine-free gold complexes as cytotoxic agents.

A cationic surfactant-concentration dependent binding of a guest molecule with the nanotubes of β-cyclodextrin and its release from the nanotubular cavities

The effect of concentration of a cationic surfactant, cetylpyridinium chloride (CPyCl), on the inclusion complex between β-cyclodextrin (β-CD) and a guest molecule, trans-2-[4-(dimethylamino)styryl]benzothiazole (DMASBT), has been studied by exploiting the twisted intramolecular charge transfer (TICT) fluorescence properties of the latter. The steady-state fluorescence, fluorescence anisotropy, time-resolved fluorescence of DMASBT and dynamic light scattering (DLS) methods have been used to monitor the different phases of binding of CPyCl with the β-CD–DMASBT system. At the chosen concentration of β-CD (8.0 mM), the β-CD molecules in the presence of 5.0 μM of DMASBT exist as extended nanotubes forming rod-like suprastructures along with simple adducts and single nanotubes. At a very low concentration of CPyCl (<0.7 mM), it partially binds with all the forms of β-CD–DMASBT inclusion complexes. Above 0.7 mM, CPyCl effectively binds with the β-CD–DMASBT system forming a β-CD–DMASBT–CPyCl complex. The premicellar aggregation starts at ∼10.0 mM of CPyCl, while micellization occurs at ∼20.0 mM, which is suggested to be the apparent critical micellar concentration (CMC*) of CPyCl. Above CMC*, the CPyCl molecules replace almost all DMASBT molecules from the cavities of nanotubes and the released DMASBT molecules then get solubilized in the micelles of CPyCl. This phenomenon suggests that the present system can be explored for the development of a drug-delivery system. The hydrodynamic radii of various components in the solution have been determined by the DLS method.

Gas-phase reactions of doubly charged actinide cations with alkanes and alkenes—probing the chemical activity of 5f electrons from Th to Cm

Small alkanes (methane, ethane, propane, n-butane) and alkenes (ethene, propene, 1-butene) were used to probe the gas-phase reactivity of doubly charged actinide cations, An(2+) (An = Th, Pa, U, Np, Pu, Am, Cm), by means of Fourier transform ion cyclotron resonance mass spectrometry. Different combinations of doubly and singly charged ions were observed as reaction products, comprising species formed via metal-ion induced eliminations of small molecules, simple adducts and ions resulting from electron, hydride or methide transfer channels. Th(2+), Pa(2+), U(2+) and Np(2+) preferentially yielded doubly charged products of hydrocarbon activation, while Pu(2+), Am(2+) and Cm(2+) reacted mainly through transfer channels. Cm(2+) was also capable of forming doubly charged products with some of the hydrocarbons whereas Pu(2+) and Am(2+) were not, these latter two ions conversely being the only for which adduct formation was observed. The product distributions and the reaction efficiencies are discussed in relation to the electronic configurations of the metal ions, the energetics of the reactions and similar studies previously performed with doubly charged lanthanide and transition metal cations. The conditions for hydrocarbon activation to occur as related to the accessibility of electronic configurations with one or two 5f and/or 6d unpaired electrons are examined and the possible chemical activity of the 5f electrons in these early actinide ions, particularly Pa(2+), is considered.

Hypervalent neutral O-donor ligand complexes of silicon tetrafluoride, comparisons with other group 14 tetrafluorides and a search for soft donor ligand complexes

The hypervalent adducts of SiF(4), trans-[SiF(4)(R(3)PO)(2)] (R = Me, Et or Ph), cis-[SiF(4){R(2)P(O)CH(2)P(O)R(2)}] (R = Me or Ph), cis-[SiF(4)(pyNO)(2)] and trans-[SiF(4)(DMSO)(2)] have been prepared from SiF(4) and the ligands in anhydrous CH(2)Cl(2), and characterised by microanalysis, IR and VT multinuclear ((1)H, (19)F, (31)P) NMR spectroscopy. The NMR studies show extensive dissociation at ambient temperatures in non-coordinating solvents, but mixtures of cis and trans isomers of the monodentate ligand complexes were identified at low temperatures. Crystal structures are reported for trans-[SiF(4)(R(3)PO)(2)] (R = Me or Ph), and cis-[SiF(4)(pyNO)(2)]. The GeF(4) analogues cis-[GeF(4){R(2)P(O)(CH(2))(n)P(O)R(2)}] (R = Me or Ph, n = 1; R = Ph, n = 2) were similarly characterised and the structures of cis-[GeF(4){R(2)P(O)CH(2)P(O)R(2)}] (R = Me or Ph) determined. The reaction of R(3)AsO (R = Me or Ph) with SiF(4) does not give simple adducts, but forms [R(3)AsOH](+) cations as fluorosilicate salts. SiF(4) adducts of some ether ligands (including THF, 12-crown-4) were also characterised by (19)F NMR spectroscopy in solution at low temperatures (∼190 K), but are fully dissociated at room temperature. Attempts to isolate, or even to identify, SiF(4) adducts with phosphine or thioether ligands in solution at 190 K were unsuccessful, contrasting with the recent isolation and detailed characterisation of GeF(4) analogues. The chemistry of SiF(4) with these oxygen donor ligands, and with soft donors (P, As, S or Se), is compared and contrasted with those of GeF(4), SnF(4) and SiCl(4). The key energy factors determining stability of these complexes are discussed.

Reactions of an Aluminum Amide with Aromatic Nitriles: Formation of Al−N−C Frameworks

Reactions of a four-membered Al−N ring, [(Dipp)HNAlMe2]2 (2; Dipp =2,6-diisopropylphenyl), with the aromatic nitriles PhCN, TbpCN (Tbp =4-tert-butylphenyl), DmpCN (Dmp = 2,6-dimethylphenyl), DepCN (DepCN = 2,6-diethylphenyl), and DippCN are reported. 2 reacts with PhCN to give a 1:2 insertion product, the tetrameric aluminum amidinate 3, whereas with TbpCN it gives the 1:1 insertion products 4−6. Under similar conditions, DmpCN, DepCN, and DippCN do not undergo insertion but form simple adducts of alumazene (1), 7a−c and 8a−c (2:1 and 1:1 nitrile/alumazene), in which the nitriles coordinate to Al. Compounds 3−6 and 7a−c have been structurally characterized. 3 is comprised of four four-membered aluminum amidinate rings. 5 features a core made of three Al2N2 and two AlCN2 four-membered rings fused together. The structures of 4 and 6 consist of a dimer of a six-membered Al2CN3 framework. A high-yield synthesis of 3 from N-(Dipp)benzamidine and AlMe3 has also been reported.

Structure-Function Relationships in Miscoding by Sulfolobus solfataricus DNA Polymerase Dpo4: GUANINE N2,N2-DIMETHYL SUBSTITUTION PRODUCES INACTIVE AND MISCODING POLYMERASE COMPLEXES

Structure-Function Relationships in Miscoding by Sulfolobus solfataricus DNA Polymerase Dpo4: GUANINE N2,N2-DIMETHYL SUBSTITUTION PRODUCES INACTIVE AND MISCODING POLYMERASE COMPLEXES

Characterization of guest molecule concentration dependent nanotubes of β-cyclodextrin and their secondary assembly: Study with trans-2-[4(dimethylamino)styryl]benzothiazole, a TICT-fluorescence probe

The formation of nanotubes of β-cyclodextrins (β-CD) and their secondary assembly induced by trans-2-[4-(dimethylamino)styryl]benzothiazole (DMASBT) as a guest molecule has been explained using twisted intramolecular charge transfer (TICT) fluorescence, steady state fluorescence anisotropy, time-correlated single-photon counting fluorescence decay of DMASBT, atomic force microscopy and also transmission electron microscopy. It has been demonstrated that although at lower concentration of β-CD, DMASBT molecules form simple adduct of 1:1 stoichiometry but they form extended nanotubes at relatively high concentration of β-CD which further lead to the secondary assembly through intertubular hydrogen bondings forming rod-like structures. The changes in fluorescence properties of DMASBT yield critical aggregation concentration (CAC) of β-CD very close to 2.5 mM. The extent of formation of these supramolecular structures is dependent on the concentration of guest molecule. It has been observed that perchlorate ion (ClO 4 −) reduces the stability of supramolecular structures at higher concentration of it but at low concentration (<7 mM) it enhances the stability by providing the anchor sites for intermolecular hydrogen bonding between neighboring β-CD molecules. The polarity and viscosity dependent TICT fluorescence characteristics of DMASBT are exploited to determine the micropolarity and microviscosity of environment around it inside the nanotubes.

Phenylhydrazine Compounds of Aluminum and Gallium – from Adducts to Cyclic Hydrazides and Cages

AbstractThe reactions of trialkyl‐element compounds (E = Al, Ga) with hydrazines usually proceed by the intermediate formation of the simple adducts R3E←NH2‐N(H)‐R′. However, only one adduct (1; R = iPr, E = Ga) could be isolated and characterized in the reactions of ER3 compounds bearing relatively small substituents with phenylhydrazine. In all other cases fast secondary processes gave directly the corresponding dimeric hydrazides [R2E–N(H)–N(H)‐C6H5]2 (2 to 4; R = Me, Et; E = Al, Ga) by gas evolution below room temperature. In contrast, decomposition of the adduct 1 required boiling toluene to produce the hydrazide 5. Compounds 3 and 4 possess four‐membered E2N2 heterocycles with two exocyclic N–N bonds in the solid state, while a five‐membered Ga2N3 heterocycle with an endocyclic and an exocyclic N–N bond was found in the crystal structure of 5. These hydrazides exhibit a dynamic behavior in solution with a complicated equilibrium between four‐ and five‐membered rings and cis‐/trans‐isomers. Further thermolysis of the hydrazides 2 and 4 inboiling toluene or at 200 °C afforded the cage compounds [(R)E–N(H)–N–C6H5]4 (6 and 7, E = Al, Ga) in which two six‐membered E2N4 heterocycles with a boat conformation are connected by four Al–N bonds.

The reaction of tin(iv) iodide with phosphines: formation of new halotin anions

The reaction of SnI(4) with each of a primary, secondary and tertiary phosphine has been investigated and in none of the cases are simple adducts formed. With Cy(3)P, [Cy(3)PI](+) salts of both [SnI(3)](-) (1) and [SnI(5)](-) (2) are isolated arising from reactions involving both reduction at tin and halogen transfer. With the secondary and primary amines Ph(2)PH and CyPH(2), respectively, additional HI elimination reactions occur and the salts [Ph(2)PH(2)](+)(6)[Sn(3)I(12)](6-) (3), [Ph(2)PH(2)](+)(2)[SnI(6)](2-) (4) and [CyPH(3)](+)(2)[SnI(4)](2-) (5) have been isolated. Compounds 1-5 have been characterised crystallographically.

Reactions of Halogens/Interhalogens with Polypyridyl Substrates: The Case of 2,4,6‐Tris(2‐pyridyl)‐1,3,5‐triazine

AbstractThe reactions between 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine (tptz) and halogens (Br2, I2) or interhalogens (ICl, IBr) yielded different products isolated in the solid state. (Htptz+)(Br3–), (Htptz+)(IBr2–), (H3tptz3+)(I3Br4–)(IBr2–)2, and (H3tptz3+)(ICl2–)3, obtained from the reactions between tptz and Br2, IBr, and ICl, were characterized by single‐crystal X‐ray diffraction and FT‐Raman spectroscopy. All compounds are salts containing the protonated donor counterbalanced by polyhalide anions of various complexity. In particular, in (H3tptz3+)(I3Br4–)(IBr2–)2 the first example of a planar I3Br4– moiety can be observed. In the case of the reaction between tptz and I2, the elemental analysis of the product indicates a 1:1 molar ratio between tptz and I2, but the FT‐Raman spectrum is not consistent with the formation of a simple adduct, clearly indicating the simultaneous presence of diiodine and symmetric triiodide. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2008)

Migratory Insertion of the R2P Group into a Nitrogen−Nitrogen Bond − A Novel Type of Rearrangement in Phosphorus−Nitrogen Ligand Chemistry. 3. The Rearrangement of Triphosphinohydrazide Ligand −N(PPh2)−N(PPh2)2 to Triphosphazenide Anion {[(Ph2P−N]2PPh2}− in the Coordination Sphere of Divalent Cobalt and Nickel

Hydrazine dihydrochloride reacts with 3 equiv of Ph2PCl in tetrahydrofuran in the presence of triethylamine to give tris(diphenylphosphino)hydrazine (1) in 70% yield. Each nitrogen atom in 1 has a trigonal-planar environment according to X-ray analysis. Thermolysis of 1 at 130 degrees C results in the formation of two products: bis(diphenylphosphino)amine and octaphenylcyclotetraphosphazene. The interaction of free ligand 1 with NiBr2 affords a simple adduct [(Ph2P)2N-NH-PPh2]NiBr2, while its anionic (hydrazide) form undergoes rearrangement in a coordination sphere of divalent cobalt and nickel involving migratory insertion of the Ph2P group into a nitrogen-nitrogen bond. The reaction of 1 with cobalt bis(trimethylsilyl)amide, [(Me3Si)2N]2Co, yields the complex of phosphazenide-type (Me3Si)2N-Co[(Ph2PN)2PPh2] (2) in 86% yield. A similar reaction of 1 with nikelocene proceeds with substitution of one Cp ring to form durable 18-electron complex CpNi[(Ph2PN)2PPh2] (3).

Acid–Base Bifunction and Umpolung of the Bridging Hydride in a Coordinatively Unsaturated Mesylimido- and Hydrido-Bridged Diiridium Complex

The mono(mesylamido)-bridged diiridium(III) complex [(Cp*IrCl)2(μ2-H)(μ2-NHMs)] (Cp* = η5-C5(CH3)5, Ms = SO2CH3) undergoes reversible dehydrochlorination to afford the unsaturated imido-bridged dinuclear complex [Cp*Ir(μ2-H)(μ2-NMs)IrClCp*] (2). The reaction of 2 with trimethylphosphine gives the simple adduct [Cp*Ir{P(CH3)3}(μ2-H)(μ2-NMs)IrClCp*], while the reaction with CO results in sequential formation of the mono- and dicarbonyl Ir(II) complexes [Cp*Ir(CO)(μ2-NHMs)IrClCp*] and [{Cp*Ir(CO)}2(μ2-NMs)] with concomitant umpolung of the bridging hydrido ligand in 2 to the amido proton.

Different Reactivity Patterns in the Reactions of the Homologous Trimethylelement Compounds EMe3 (E = Al, Ga, In) with Methylhydrazine

AbstractThe trimethylelement compounds EMe3 (E = Al, Ga, In) followed three different reaction courses upon treatment with methylhydrazine, H2N–N(H)Me. AlMe3 reacted at room temperature by releasing 1.5 equiv. methane to yield the sesquihydrazide (Me2Al)3[μ‐NH–N(H)Me]6Al (1), which in the solid state has a hexacoordinate central aluminum atom and six hydrazido groups in the bridging positions to the three terminally arranged AlMe2 groups. Dissociation occurred upon dissolution, and the dialuminum compound Me2Al[μ‐NH–N(H)Me]2Al(Me)[NH–N(H)Me] (2), containing one terminal hydrazido group, was identified unambiguously by NMR spectroscopy. GaMe3 gave a simple adduct, Me3Ga←N(H)Me–NH2 (3), under the same reaction conditions. Boiling toluene was required to initiate a secondary reaction with the release of methane. A bicyclic tetragallium compound, 4, in which a twofold deprotonated hydrazide, [HN–NMe]2–, bridges four gallium atoms, was the result. Each pair of gallium atoms on both sides of the central hydrazinediide ligand is further bridged by the monoanionic hydrazide [HN–N(H)Me]– to yield two annelated, five‐membered Ga2N3 heterocycles. A similar compound, 5, was directly obtained from the reaction of InMe3 with methylhydrazine at room temperature.(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2008)