Synthesis and reactivity of 4,5-[1,2-dicarba-closo-dodecaborano(12)]-1,3-diselenacyclopentane: opening of the icosahedron to give a zwitterionic intermediate and conversion into 7,8-dicarba-nido-undecaborate(1-)

The reaction of the 1,2-diselenolato-1,2-dicarba-closo-dodecaborane(12) dianion [1,2-(1,2-C(2)B(10)H(10))Se(2)](2-) with dichloromethane (CH(2)Cl(2) or CD(2)Cl(2)) in the presence of donor solvents gave 4,5-[1,2-dicarba-closo-dodecaborano(12)]-1,3-diselenacyclopentane, the title compound, which was characterized by X-ray structural analysis and NMR spectroscopy ((1)H, (11)B, (13)C, and (77)Se). In the presence of pyridine, opening of the icosahedron took place, and a zwitterionic intermediate was isolated and fully characterized in the solid state by X-ray diffraction and in solution by multinuclear magnetic resonance techniques. Although such types of intermediates, prior to deboronation of the ortho-carborane cage, have been proposed several times, this is first example for which the structure has been confirmed unambiguously. This intermediate possesses a nido structure and contains a 7,8-dicarba-nido-undecaborate(1-) anion and a boronium cation, the latter with two pyridine rings linked to the boron atom, which has been extruded from the cage. It was shown that this process is reversible as long as the deboronation is not complete. The formation of the intermediate is accompanied by deboronation, which leads to the 7,8-dicarba-nido-undecaborate(1-) anion. The latter was prepared independently by conventional routes from the title compound, isolated as crystalline material as the tetrabutyl ammonium salt, and characterized by X-ray structural analysis and multinuclear magnetic resonance spectroscopy ((1)H, (11)B, (13)C, and (77)Se).     

Synthesis of derivatives of 7-iodo-4-aminoquinolines

7-Iodo- and 7,8-diiodo-4-(3-dimethylaminopropylamino)quinolines and 7-iodo-4-(3) dipropyl-aminopropylamlno)- and 7-iodo-4-(3-diallylaminopropylamino)quinoline were obtained by the reaction of 7-iodo- and 7,8-diodo-4-chloroquinolines with the corresponding diamines. The catalytic hydrogenation of 7-iodo-4-(3-diallylaminopropylamino)quinoline at normal pressure leads to 7-iodo-4-(3-dipropylaminopropylamino)quinoline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 972–975, July, 1980.     

The crystal and molecular structure of cesium 9,10,11-trimethyl-7,8-dicarba-nido-undecaborate(1-) Cs[9,10,11-Me3-7,8-C2B9H9]

Conclusions By a complete x-ray diffraction study of cesium 9,10,11-trimethyl-7,8-dicarba-nido-undecaborate(1-) we proved the axial orientation of the Me group attached to the B¹⁰ atom of the open face of the nido-carborane polyhedron. This serves as an additional proof of the stereospecificity of the alkylation reaction of the dicarbollide ions and the necessity for a migration stage of the boron atom with the substituent to the site of the deficient apex of the icosahedron to form a derivative with an equatorial disposition of the alkyl group.The atoms in the carborane polyhedron are numbered as in [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2474–2481, November, 1979.     

脱卤亚磺化研究——连二亚硫酸钠作为新的脱卤亚磺化试剂

全氟碘代烷与亚硫酸盐发生单电子转移反应生成全氟亚磺酸盐;连二亚硫酸钠水溶液热分解时,ESR表明生成SO_2~-主阴离子自由基,这两者促使我们尝试用连二亚硫酸钠代替亚硫酸盐与全氟卤代烷反应.实验表明对于全氟碘代烷及溴代烷它是一种有效的     

"Water-stable boron-iodinated dicarbollide dianions [7,8-nido-C2H2B9I9]2- and [7,8-nido-C2H2B9I8H]2-"

The reaction of 3,4,5,7,8,9,10,11,12-I(9)-1,2-closo-C(2)B(10)H(3) with KOH/EtOH gave a mixture of the boron periodinated [1,2,3,4,5,6,9,10,11-I(9)-7,8-nido-C(2)B(9)H(2)](2-) and the highly iodinated on boron [1,2,4,5,6,9,10,11-I(8)-7,8-nido-C(2)B(9)H(3)](2-) in approximately 50% each. Moreover, 3,4,5,6,7,8,9,10,11,12-I(10)-1,2-closo-C(2)B(10)H(2) was reacted with KOH/EtOH to purely produce [1,2,3,4,5,6,9,10,11-I(9)-7,8-nido-C(2)B(9)H(2)](2-). It is the first dinegative dicarbollide stable in water or protic solvent reported in literature.     

On the reaction of nido-carborane with thiourea

Russian Chemical Bulletin - A reaction of the protonated form of 7,8-dicarba-nido-undecaborate anion 7,8-C2B9H13 with thiourea leads to the formation of a mixture of 9- and 10-thiuronium...     

Gold(I) Complexes with the nido-Diphosphino Ligand [7,8-(Ph(2)P)(2)-7,8-C(2)B(9)H(10)](-). Preparation of the First Metallocarborane Complex of this Ligand. Crystal Structures of [Au{(PPh(2))(2)C(2)B(9)H(10)}(PPh(3))].CH(2)Cl(2) and [Au(2){(PPh(2))(2)C(2)B(9)H(10)}(2){(PPh(2))(2)(CH(2))(3)}].3Me(2)CO

The reaction of [AuCl(PR(3))] with [1,2-(Ph(2)P)(2)-1,2-C(2)B(10)H(10)] in refluxing ethanol proceeds with partial degradation (removal of a boron atom adjacent to carbon) of the closo species to give [Au{(PPh(2))(2)C(2)B(9)H(10)}(PR(3))] [PR(3) = PPh(3) (1), PPh(2)Me (2), PPh(2)(4-Me-C(6)H(4)) (3), P(4-Me-C(6)H(4))(3) (4), P(4-OMe-C(6)H(4))(3) (5)]. Similarly, the treatment of [Au(2)Cl(2)(&mgr;-P-P)] with [1,2-(Ph(2)P)(2)-1,2-C(2)B(10)H(10)] under the same conditions leads to the complexes [Au(2){(PPh(2))(2)C(2)B(9)H(10)}(2)(&mgr;-P-P)] [P-P = dppe = 1,2-bis(diphenylphosphino)ethane (6), dppp = 1,3-bis(diphenylphosphino)propane (7)], where the dppe or dppp ligands bridge two gold nido-diphosphine units. The reaction of 1 with NaH leads to removal of one proton, and further reaction with [Au(PPh(3))(tht)]ClO(4) gives the novel metallocarborane compound [Au(2){(PPh(2))(2)C(2)B(9)H(9)}(PPh(3))(2)] (8). The structure of complexes 1 and 7 have been established by X-ray diffraction. [Au{(PPh(2))(2)C(2)B(9)H(10)}(PPh(3))] (1) (dichloromethane solvate) crystallizes in the monoclinic space group P2(1)/c, with a = 17.326(3) ?, b = 20.688(3) ?, c = 13.442(2) ?, beta = 104.710(12) degrees, Z = 4, and T = -100 degrees C. [Au(2){(PPh(2))(2)C(2)B(9)H(10)}(2)(&mgr;-dppp)] (7) (acetone solvate) is triclinic, space group P&onemacr;, a = 13.432(3) ?, b = 18.888(3) ?, c = 20.021(3) ?, alpha = 78.56(2) degrees, beta = 72.02(2) degrees, gamma = 73.31(2) degrees, Z = 2, and T = -100 degrees C. In both complexes the gold atom exhibits trigonal planar geometry with the 7,8-bis(diphenylphosphino)-7,8-dicarba-nido-undecaborate(1-) acting as a chelating ligand.     

Utility of 5-Diazo-1,2,4- Triazol-3-Carboxylic Acid for Colorimetric Determination of Certain 8-Hydroxyquinolines

Abstract

A colorimetric method for the determination of certain 8-hydroxyquinolines has been developed. The method is based on the coupling of 8-quinolinols with diazotriazole carboxylic acid in the presence of sodium carbonate (0.5% w/v) at ambient temperature (around 30°C). The resulting azo dyes are stable and give intense absorption in the range of 486–540 nm. Beer's law is valid in the concentration ranges of 1 – 8, 2.5 – 17.5, 5 – 35, 2 – 20, and 2 – 20 mcg/ml for 8-hydroxyquinoline (HQ), 5,7-diiodo-8-hydroxyquinoline (DIQ), 5,7-dibromo-8-hydroxyquinoline (DBQ), 5-chloro-7-iodo-8-hydroxyquinoline (CIQ) and 8-hydroxy-7-iodo-5-quinoline sulfonic acid (SIQ), respectively. The proposed method has been successfully applied for the determination of the studied compounds in pure form and in commercial formulations. The obtained results are in good agreement with those obtained from reported methods.     

Synthesis, reactivity and complexation studies of N,S exo-heterodisubstituted o-carborane ligands. Carborane as a platform to produce the uncommon bidentate chelating (pyridine)N-C-C-C-s(H) motif

The synthesis of N,S-heterodisubstituted 1-(2'-pyridyl)-2-SR-1,2-closo-C2B10H10 compounds (R = Et, 2; R = (i)Pr, 3) has been accomplished starting from 1-(2'-pyridyl)-l,2-closo-C2B10H11 (1), and their partial deboronation reaction leading to the structurally chiral [7-(2'-pyridyl)-8-SR-7,8-nido-C2B9H10]-derivatives (R = Et, [4]-; R = (i)Pr, [5]-) has been studied. Capillary electrophoresis combined with the chiral selector alpha-cyclodextrin has permitted the separation of the electrophoretically pure racemic [7-(2'-pyridyl)-8-SR-7,8-nido-C2B9H11]- ions into two peaks each one corresponding to the interaction of one enantiomer with the alpha-cyclodextrin. The N,S-heterodisubstituted o-carborane containing a mercapto group, 1-(2'-pyridyl)-2-SH-1,2-closo-C2B10H10, 1, is one of the two examples of a rigid bidentate chelating (pyridine)N-C-C-C-S(H) motif having been structurally fully characterized. To study the potential of such a binding site, 1 has been tested as a ligand with metal ions requiring different coordination numbers, two (Au(+)) and four (Pd2+ and Rh+). The crystal structures of the Pd(II) and Au(I) complexes are reported. For the Pd(II) complex, 1 acts as a bidentate ligand whereas for Au(I), 1 acts as a monodentate ligand through the thiolate.     

Synthesis and structural characterization of mono- and bisfunctional o-carboranes

Functionalized o-carboranes are interesting ligands for transition metals. Reaction of LiC2B10H11 with Me2NCH2CH2Cl in toluene afforded 1-Me2NCH2CH2-1,2-C2B10H11 (1). Treatment of 1 with 1 equiv. of n-BuLi gave [(Me2NCH2CH2)C2B10H10]Li ([1]Li), which was a very useful synthon for the production of bisfunctional o-carboranes. Reaction of [1]Li with RCH2CH2Cl afforded 1-Me2NCH2CH2-2-RCH2CH2-1,2-C2B10H10 (R = Me2N (2), MeO (3)). 1 and 2 were also prepared from the reaction of Li2C2B10H10 with excess Me2NCH2CH2Cl. Treatment of [1]Li with excess MeI or allyl bromide gave the ionic salts, [1-Me3NCH2CH2-2-Me-1,2-C2B10H10][I] (4) and [1-Me2N(CH2=CHCH2)CH2CH2-2-(CH2=CHCH2)-1,2-C2B10H10][Br] (6), respectively. Interaction of [1]Li with 1 equiv. of allyl bromide afforded 1-Me2NCH2CH2-2-(CH2=CHCH2)-1,2-C2B10H10 (5). Treatment of [1]Li with excess dimethylfulvene afforded 1-Me2NCH2CH2-2-C5H5CMe2-1,2-C2B10H10 (7). Interaction of [1]Li with excess ethylene oxide afforded an unexpected product 1-HOCH2CH2-2-(CH2=CH)-1,2-C2B10H10 (8). 1 and 3 were conveniently converted into the corresponding deborated compounds, 7-Me2NHCH2CH2-7,8-C2B9H11 (9) and 7-Me2NHCH2CH2-8-MeOCH2CH2-7,8-C2B9H10 (10), respectively, in MeOH-MeOK solution. All of these compounds were characterized by various spectroscopic techniques and elemental analyses. The solid-state structures of 4 and 6-10 were confirmed by single-crystal X-ray analyses.     

Synthesis of indeno-fused derivatives of quinolizinium salts, imidazo[1,2-a]pyridine, pyrido[1,2-a]indole, and 4h-quinolizin-4-one via benzannulated enyne-allenes

The benzannulated enediynyl propargylic alcohol 8 was prepared from 1-bromo-2-iodobenzene by two consecutive Sonogashira cross-coupling reactions. The subsequent transformation to mesylate 9 followed by treatment with 4-substituted pyridines 10 then furnished the benzannulated enediynes 11. On exposure of 11 to triethylamine, the indeno-fused quinolizinium salts 15 were produced in quantitative yield. Presumably the reaction proceeded through a 1,3-prototropic rearrangement to form the benzannulated enyne-allenes 12, which then underwent either a concerted Diels-Alder reaction or a two-step process involving a Schmittel cyclization reaction to form biradical 13 followed by an intramolecular radical-radical coupling to afford 14. A subsequent prototropic rearrangement then produced 15. Similarly, 21a and 21b were produced from 19a and 19b, respectively. The use of the Sonogashira reaction for cross-coupling between 1-iodo-2-(phenylethynyl)benzene (7) and 1-(2-propynyl)-1H-imidazole (25) followed by treatment of the resulting adduct with potassium tert-butoxide gave the indeno-fused imidazo[1,2-a]pyridine 24 in 98% yield. Similarly, the indeno-fused pyrido[1,2-a]indole 32 and 4H-quinolizin-4-one 35 were obtained by starting from 7 for cross-coupling with 1-(2-propynyl)-1H-indole (30) and 1-(2-propynyl)-2(1H)-pyridinone (33), respectively, followed by treatment with potassium tert-butoxide.     

Halogenation of the 7,8-dicarba-<Emphasis Type="Italic">nido</Emphasis>-undecaborate anion derivatives [10-RO-7,8-C<Subscript>2</Subscript>B<Subscript>9</Subscript>H<Subscript>11</Subscript>]<Superscript>−</Superscript>

Iodination and bromination of 10-alkoxyderivatives of 7,8-dicarba-nido-undecaborate anion [10-RO-7,8-C₂B₉H₁₁]⁻ has been studied. The corresponding monoiodo, diiodo and dibromo derivatives were prepared.     

η5‐(3)‐1‐Methyl‐1,2‐dicarbollyl‐η5‐2′,5′‐dimethylpyrrolylcobalt(III)

In the title compound, (η⁵‐2,5‐di­methyl­pyrrolyl)[(7,8,9,10,11‐η)‐7‐methyl‐7,8‐dicarba‐nido‐undecaborato]­cobalt(III), [3‐Co{η⁵‐[2,5‐(CH₃)₂‐NC₄H₂]}‐1‐CH₃‐1,2‐C₂B₉H₁₀] or [Co(C₃H₁₃B₉)(C₆H₈N)], the Co^III atom is sandwiched between the pentagonal faces of the pyrrolyl and dicarbollide ligands, resulting in a neutral mol­ecule. The C—C distance in the dicarbollide cage is 1.649 (3) Å.     

Synthesis, reactivity and structural studies of carboranyl thioethers and disulfides

The equimolar reaction of 1-SH-2-R-1,2-closo-C2B10H10(R=Me, H, Ph) with KOH in ethanol produces the thiolate species [1-S-2-R-1,2-closo-C2B10H10]-. These react with iodine to give the disulfide bridged dicluster (1-S-2-R-1,2-closo-C2B10H10)2(R=H, Me, Ph) compounds as analytically pure, white and air-stable solids in high yield. Synthesis of monothioether bridged species is synthetically more difficult. In fact three procedures have been tested to obtain the thioether bridged dicluster compounds (2-R-1,2-closo-C2B10H10)2S (R=Me, H, Ph) but only (2-Me-1,2-closo-C2B10H10)2S was successfully synthesized and characterized. Attempts to produce mixed compounds (1-R-1,2-closo-C2B10H10)S(1-R'-1,2-closo-C2B10H10), R not=R', were unsuccessful. Deboronation reaction of this dicarboranylthioether lead, depending on the reaction conditions, to monoanionic [(2-Me-1,2-closo-C2B10H10)S(8-Me-7,8-nido-C2B9H10)]- or dianionic [(8-Me-7,8-nido-C2B9H10)2S]2- sulfur bridge anions. Deboronation of carboranyl disulfides gave the corresponding dianionic [(7-S-8-R-7,8-nido-C2B9H10)2]2-(R=H, Me, Ph) species. This reaction was very dependent, however, on the reaction conditions. With slight variation of the reaction conditions, splitting of the S-S bond leading to the thiolate species with retention of the closo cluster was also found. Carboranyl disulfides (1-S-2-R-1,2-closo-C2B10H10)2(R=H, Me, Ph) do not lead to thiosulfinates R-S(O)-S-R' by oxidation with H2O2 or I2 as organic disulfides do. This behaviour is attributed to the presence of the sulfur atom directly bonded to the carbon cluster that produces electronic transfer from the filled orbitals on the sulfur atom into the cage LUMO (largely located on the cage Cc-Cc bond). This causes a depletion of electron density on the sulfur, thence impairing sulfur oxidation, and facilitating S-S breaking. Crystal structures of monothioethers (2-Me-1,2-closo-C2B10H10)2S, [NMe4][(2-Me-1,2-closo-C2B10H10)S(8-Me-7,8-nido-C2B9H10)](the first example reported in the literature of a two cluster compound incorporating the closo C2B10 and the nido[C2B9]- moieties linked by a one member spacer) and disulfides (1-S-1,2-closo-C2B10H11)2, (1-S-2-Me-1,2-closo-C2B10H10)2, (1-S-2-Ph-1,2-closo-C2B10H10)2 are reported which support the behaviour of these species.     

Unexpected formation of ruthenium(II) hydrides from a reactive dianiline precursor and 1,2-(Ph2P)2-1,2-closo-C2B10H10

Reaction of the new precursor cis, trans-Ru(cod)(anln)2Cl2 with the diphosphine 1,2-bis(diphenylphosphino)-1,2-dicarba-closo-dodecaborane (o-dppc) unexpectedly results in two new ruthenium(II) hydrides, trans-Ru(o-dppc) 2(H)Cl and the neutral, five-coordinate complex Ru(o-dppc)(nido-dppc)(H), depending upon the reaction conditions [anln is aniline and nido-dppc is 7,8-(Ph2P)2C2B9H10(-)]. Chloride abstraction from trans-Ru(o-dppc)2(H)Cl leads to another five-coordinate hydride, [Ru(o-dppc)2(H)](+), which is isolated as either a triflate or hexafluorophosphate salt. On the basis of labeling and reactivity studies, the source of the hydride appears to be the cod ligand.     

Contribution of the nido-[7,8-C2B9H10]- anion to the chemical stability, basicity, and 31P NMR chemical shift in nido-o-carboranylmonophosphines

The icosahedral dicarboranes and their decapitated anion, 1-R'-1,2-C(2)B(10)H(10) (closo) and [7-R'-7,8-C(2)B(9)H(10)](-) (nido), exert a distict influence at the alpha position of substituents attached to the cage carbon atom. The closo fragment is electron-withdrawing while the nido anion is electron-releasing. These effects are studied by (31)P NMR, phosphorus oxidation, and phosphorus protonation in [7-PR(2)-8-R'-7,8-C(2)B(9)H(10)](-) species. The (31)P NMR chemical shift dependence is related to the R alkyl or aryl nature of [7-PR(2)-8-R'-7,8-C(2)B(9)H(10)](-). No direct relationship to the nature of the R substituent on the nido-carboranylmonphosphine toward oxidation has been found. The basicity of the nido-alkylcarboranylmonophosphines is the highest while the lowest corresponds to the nido-arylcarboranylmonophosphines. Interpretation can be carried out qualitatively by considering the electronic properties of the cluster and the nature of the R groups. The influence of R' is less relevant. Confirmation of the molecular structure of the oxidated and protonated nido-carboranylmonophosphine compounds was obtained by X-ray diffraction analysis of [NBu(4)][7-P(O)Ph(2)-8-Ph-7,8-C(2)B(9)H(10)] and [7-PH((i)Pr)(2)-8-Me-7,8-C(2)B(9)H(10)].     

Synthesis of unsaturated 7,8- and 7,9-di(hydroxymethyl)decahydro-7,8- and-7,9-dicarba-nido-undecaborate(1−) diethers

Dicarba-nido-undecaborate(1–) anions were obtained by treatment of 1,2-di(hydroxymethyl)-1,2-dicarba-closo-dodecaborane(12) diallyl ether, 1,2-di(hydroxymethyl)-1,2-dicarba-closo-dodecaborane (12), and 1,7-di(hydroxymethyl)-1,7-dicarba-closo-dodecaborane(12) with ethanolic solutions of KOH and subsequent reaction of the products with cesium and tetramethylammonium chlorides.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1821–1823, September, 1995.     

Cooperative effect of carborane and pyridine in the reaction of carboranyl alcohols with thionyl chloride: halogenation versus oxidation

Thionyl chloride (SOCl2) acts as halogenation reagent in its reaction with 1-[phenyl(hydroxy)methyl]-2-R-1,2-dicarba-closo-dodecaborane 1a, b but unexpectedly behaves as an oxidant for 1-[2'-pyridyl(hydroxy)methyl]-2-R-1,2-dicarba-closo-dodecaboranes 2a, b. The synthesis and characterization of all new compounds, including structure determinations of 1a, 2a, 1-[phenyl(chloro)methyl]-2-methyl-1,2-dicarba-closo-dodecaborane 3a, and 1-[2'-pyridyl(oxo)methyl]-2-methyl-1,2-dicarba-closo-dodecaboranes 4a are reported and the possible pathways are discussed.     

Synthesis and reactions of halo-, nitro-, and arylazo-substituted 3-acetyltropolones. Formation of heterocycle-fused troponoid compounds

3-Acetyltropolone ( 1 ) reacted with bromine, iodine, and nitric acid to afford respectively 3-acetyl-5,7-di-bromotropolone ( 2 ), 3-acetyl-7-iodotropolone ( 3 ), and 3-acetyl-5-nitro- ( 4 ) and 3-acetyl-5,7-dinitrotropolone ( 5 ). Azo-coupling reactions of 1 gave 3-acetyl-5-arylazotropolones 7a-f. The Schmidt reactions of 2 and 3 gave respectively 5,7-dibromo- ( 9 ) and 7-iodo-2-methyl-8H-cyclohept[d]oxazol-8-one ( 10 ), while 4 gave 3-acetamido-5-nitrotropolone ( 11 ). Compounds 2 and 4 reacted with hydroxylamine to give 3-methyl-8H-cyclohept[d]isoxazol-8-ones 12 and 13. The reactions of 2 , 3 , and 4 with hydrazine gave 3-methyl-1,8-dihydrocycloheptapyrazol-8-ones 15 , 16 , and 17.     

The dianion of 5-cyanoiminotetrazoline: C2N62-

Several salts (alkali, Pd(NH(3))(3), and (i)PrNH(2)) of 5-cyanoiminotetrazoline (C(2)N(6)(2-), 5-cyanoiminotetrazolinediide, CIT) were investigated. A full characterization by means of X-ray, Raman, NMR techniques, mass spectrometry, and elemental analysis is presented for the (i)()PrNH(2) (4), Cs (5), and Pd(NH(3))(3) (6) salts. The CIT dianion represents a nitrogen-rich binary CN dianion, and 5 forms monoclinic crystals (a = 7.345(2) Angstroms, b = 9.505(2) Angstroms, c = 10.198(2) Angstroms, beta = 92.12(3) degrees, space group P2(1)/n, Z = 4). DSC and in situ temperature-dependent X-ray diffraction measurements of the cesium salt 5 revealed an astonishing thermal stability accompanied by a reversible phase transition from the low-temperature alpha modification to the metastable beta modification at 253 degrees C. Above the melting point (334 degrees C), the cesium salt decomposes yielding cesium azide and cesium dicyanamide, which decomposes under further heating under release of nitrogen. The reaction of Cs(2)CIT with SO(2) resulted in the surprising formation of a new cesium salt with the 5-cyaniminotetrazoline-1-sulfonate dianion (Cs(2)CITSO(3).SO(2) (7)). 7 crystallizes in the monoclinic space group P2(1) with one SO(2) solvent molecule (a = 8.0080(2) Angstroms, b = 8.0183(2) Angstroms, c = 9.8986(3) Angstroms, beta = 108.619(1) degrees, Z = 2). The structure and bonding of the 10pi dianion are discussed on the basis B3LYP/aug-cc-pvTZ computations (MO, NBO), and the three-dimensional array of the cesium salts with respect to the Cs(delta) (+)-N(delta)(-) in 5 compared to the Cs(delta)(+)-N(delta)(-) and Cs(delta)(+)-O(delta)(-) in 7 is discussed. Due to the expected rich bonding modes of the CIT anions, the coordination chemistry with palladium was also studied, yielding monoclinic crystals of [Pd(CIT)(NH(3))(3)].H(2)O (6, a = 7.988(2) Angstroms, b = 8.375(2) Angstroms, c = 13.541(3) Angstroms, beta = 104.56 degrees, space group P2(1)/n, Z = 4). In the solid state, the complex is composed of dimers, showing two agostic interactions and an unusual close interplanar pi-pi stacking of the tetrazole moiety of the CIT ligand.