The mechanism of fluxionality of (1,2,7-η3-2-Me-benzyl)(η5-C5H5)Mo(CO)2

It is shown that (1,2,7-η³-2-Me-benzyl)(η⁵-C₅H₅)Mo(CO)₂ exits in solution as one isomer which is fluxional, probably via (7-η¹-2-Me-benzyl)((η⁵-C₅H₅)Mo(CO)₂, with ΔG^≠₃₇₀ = 23.6 ± 1.0 kcal mol⁻¹. In contrast, (1,2,7-η³-3-Me-benzyl)(η⁵-C₅H₅)Mo(CO)₂ exits as two isomers at −20°C, which undergo interconversion at room temperature with ΔG^≠ 15.7 kcal mol⁻¹. This dynamic process is an allyl rotation. It is probable that there is also a low energy [1,5]-sigmatropic shift.     

Stereochemistry of 2, 7-disubstituted and 1,2,7-trisubstituted 4-alkyldecahydro-4-quinolols

The configurations of the 2 and 4 centers in 1,2,7-trimethyl-, 2,7-dimethyl-, and 1,2-dimethyl-7-tert-butyl-4-alkyldecahydro-4-quinolols were assigned on the basis of a comparison of the^I[M-CH₃] +/^I _[M] ⁺ and I_[m] + peak intensity ratios (the [M-CH₃) + and [M-C₂H₅]⁺ ions are due to elimination of 2-CH₃ and 4-C₂H₅ groups, respectively) in the mass spectra of the stereoisomers.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 809–811, June, 1976.     

Rhodathiaboranes with `anomalous' electron counts: synthesis, structure and reactivity

Analysis of the structures of 8,8-(PPh₃)₂-8,7-nido-RhSB₉H₁₀ and 9,9-(PPh₃)₂-9,7,8-nido-RhC₂B₈H₁₁ by RMS misfit calculations has confirmed that these rhodaheteroboranes possess nido 11-vertex cluster geometries in apparent contravention of Wade's rules. However, examination of the molecular structures of both species shows that the {RhP₂} planes are inclined by ca. 66° with respect to the metal-bonded SB₃ or CB₃ faces, and that two weak ortho-CHRh agostic interactions occupy the vacant co-ordination position thereby created. As a consequence of these agostic bonds the Rh atom, and hence the overall cluster, is provided with an additional electron pair, meaning that their nido structures are now fully consistent with Wade's rules. The chelated diphosphine compound 8,8-(dppe)-8,7-nido-RhSB₉H₁₀ is similar to the PPh₃ compound in showing the same agostic bonding. Attempts to prepare a bis-P(OMe)₃ analogue result in ligand scavenging and the formation of 8,8,8-{P(OMe)₃}₃-8,7-nido-RhSB₉H₁₀. Similarly, reaction between Cs[6-arachno-SB₉H₁₂] and RhCl(dmpe)CO does not result in CO loss but in formation of 8,8-(dmpe)-8-(CO)-8,7-nido-RhSB₉H₁₀, shown to exist as a mixture of two of three possible rotamers. Deprotonation of 8,8-(PPh₃)₂-8,7-nido-RhSB₉H₁₀ and 8,8-(dppe)-8,7-nido-RhSB₉H₁₀ with MeLi yields the anions [1,1-(PPh₃)₂-1,2-closo-RhSB₉H₉]⁻ and [1,1-dppe-1,2-closo-RhSB₉H₉]⁻, respectively, with octadecahedral cage structures. It is argued that anion formation causes the agostic bonding to be `switched-off' and results in the cluster adopting the closo architecture predicted by Wade's rules. This structural change is fully reversible on reprotonation, and if reprotonation of [1,1-(dppe)-1,2-closo-RhSB₉H₉]⁻ is carried out in MeCN, the product 8,8-(dppe)-8-(MeCN)-8,7-nido-RhSB₉H₁₀ forms. Interestingly, 8,8-(dppe)-8-(MeCN)-8,7-nido-RhSB₉H₁₀ reconverts to 8,8-(dppe)-8,7-nido-RhSB₉H₁₀ on standing in CDCl₃, suggesting that the agostic bonding is sufficiently strong to displace co-ordinated MeCN. All new compounds are fully characterised by multinuclear NMR spectroscopy and, in many cases, by single crystal X-ray diffraction.     

Platinum Indolylphosphine Fluorido and Polyfluorido Complexes: An Interplay between Cyclometallation,Fluoride Migration,and Hydrogen Bonding

The reaction of [PtCl₂(COD)] (COD=1,5-cyclooctadiene) with diisopropyl-2-(3-methyl)indolylphosphine (iPr₂P(C₉H₈N)) led to the formation of the platinum(ii ) chlorido complexes, cis-[PtCl₂{iPr₂P(C₉H₈N)}₂] ( 1 ) and trans-[PtCl₂{iPr₂P(C₉H₈N)}₂] ( 2 ). The cis-complex 1 reacted with NEt₃ yielding the complex cis-[PtCl{κ²-(P,N)-iPr₂P(C₉H₇N)}{iPr₂P(C₉H₈N)}] ( 3 ) bearing a cyclometalated κ²-(P,N)-phosphine ligand, while the isomer 2 with a trans-configuration did not show any reactivity towards NEt₃. Treatment of 1 or 3 with (CH₃)₄NF (TMAF) resulted in the formation of the twofold cyclometalated complex cis-[Pt{κ²-(P,N)-iPr₂P(C₉H₇N)}₂] ( 4 ). The molecular structures of the complexes 1–4 were determined by single-crystal X-ray diffraction. The fluorido complex cis-[PtF{κ²-(P,N)-iPr₂P(C₉H₇N)}{iPr₂P(C₉H₈N)}] ⋅ (HF)₄ ( 5 ⋅ (HF)₄) was formed when complex 4 was treated with different hydrogen fluoride sources. The Pt(ii ) fluorido complex 5 ⋅ (HF)₄ exhibits intramolecular hydrogen bonding in its outer coordination sphere between the fluorido ligand and the NH group of the 3-methylindolyl moiety. In contrast to its chlorido analogue 3 , complex 5 ⋅ (HF)₄ reacted with CO or the ynamide 1-(2-phenylethynyl)-2-pyrrolidinone to yield the complexes trans-[Pt(CO){κ²-(P,C)-iPr₂P(C₉H₇NCO)}{iPr₂P(C₉H₈N)}][F(HF)₄] ( 7 ) and a complex, which we suggest to be cis-[Pt{C=C(Ph)OCN(C₃H₆)}{κ²-(P,N)-iPr₂P(C₉H₇N)}{iPr₂P(C₉H₈N)}][F(HF)₄] ( 9 ), respectively. The structure of 9 was assigned on the basis of DFT calculations as well as NMR and IR data. Hydrogen bonding of HF and NH to fluoride was proven to be crucial for the existence of 7 and 9 .     

Synthesis,Structure, and Luminescent Property of the Templated Borate [C9H14N]·[B5O6(OH)4]

The templated borate, [C₉H₁₄N] · [B₅O₆(OH)₄], was synthesized under hydrothermal conditions. Single crystal X‐ray diffraction techonology reveals that it crystallizes in the triclinic system, space group P$\bar{1}$ (No. 2). The material was also characterized by element analysis, Fourier transform infrared spectroscopy (FTIR), powder X‐ray diffraction (PXRD), thermogravimetric and differential thermal analysis (TG‐DTA), and luminescence spectroscopy. The compound consisted of isolated pentaborate [B₅O₆(OH)₄]^– and N‐butylpyridinium cations [C₉H₁₄N]⁺. The [B₅O₆(OH)₄]^– anions are connected together by hydrogen bonds to form a three‐dimensional framework, in which [C₉H₁₄N]⁺ cations are located in. [C₉H₁₄N] · [B₅O₆(OH)₄] exhibits tunable luminescence emission at 415–458 nm by means of heating treatment from 100 to 300 °C.     

Lamotrigine,an antiepileptic drug,and its chloride and nitrate salts

In lamotrigine [systematic name: 6‐(2,3‐dichlorophenyl)‐1,2,4‐triazine‐3,5‐diamine], C₉H₇Cl₂N₅, (I), the asymmetric unit contains one lamotrigine base molecule. In lamotriginium chloride [systematic name: 3,5‐diamino‐6‐(2,3‐dichlorophenyl)‐1,2,4‐triazin‐2‐ium chloride], C₉H₈Cl₂N₅⁺·Cl⁻, (II), the asymmetric unit contains one lamotriginium cation and one chloride anion, while in lamotriginium nitrate, C₉H₈Cl₂N₅⁺·NO₃⁻, (III), the asymmetric unit contains two crystallographically independent lamotriginium cations and two nitrate anions. In all three structures, N—H...N hydrogen bonds form an R₂²(8) dimer. In (I) and (II), hydrophilic layers are sandwiched between hydrophobic layers in the crystal packing. In all three structures, hydrogen bonds lead to the formation of a supramolecular hydrogen‐bonded network. The significance of this study lies in its illustration of the differences between the supramolecular aggregation in the lamotrigine base and in its chloride and nitrate salts.     

Synthesis and characterization of Schiff base metal complexes: their antimicrobial,genotoxicity and electrochemical properties

We have synthesized the three Schiff-base ligands H₂L¹–H₂L³ and their Co^II, Fe^III and Ru^III metal complexes. All compounds have been characterized by analytical and spectroscopic methods. Oxidation of cyclohexane has been done by the metal complexes in CH₃CN using H₂O₂ and/or t-butylhydroperoxide (TBHP) as a co-catalyst. The keto-enol tautomeric forms of the ligands have been studied in polar and non-polar organic solvents. Electrochemical properties of the complexes have been studied at different scan rates. Thermal studies were carried out for the compounds. The ligands H₂L¹–H₂L³ were mutagenic on Salmonella Typhimurium TA 98 strain in the presence and/or absence of S9 mix. While the ligands H₂L¹ and H₂L² showed mutagenic activity on the strain TA 100 with and without S9 mix, the ligand H₂L³ was not mutagenic for TA 100. Antimicrobial activity studies of the compounds have also been carried out.     

一种含咔唑基团的混配型钌(II)配合物的合成、表征和酸碱性质研究

合成了钌(II)配合物cis-[Ru(HL)(Hdcbpy)(NCS)₂]^－•[N(C₄H₉)₄]^＋ (HL＝2-(9-乙基-9H-3-咔唑基)-1H-咪唑[4,5-f] [1,10]邻菲啰啉, H₂dcbpy＝4,4'-二羧酸-2,2'-联吡啶). 采用元素分析、核磁共振氢谱、红外光谱、紫外-可见吸收光谱、质谱(MS)对配合物进行了表征. 通过紫外-可见吸收光谱和稳态荧光光谱, 研究了该配合物的基态和激发态酸碱性质. 结果表明该配合物在基态时能发生5步质子化/去质子化反应, 表现出基于光致发光强度和激发态能量转移途径的质子化/去质子化诱导的分子开关性质.     

Collisional activation spectra. Gas phase [C12H10O]+˙ and [C12H9O]+ ions from dephenyl ether,diphenyl carbonate,and o-, m- and p-phenylphenol

[C₁₂H₁₀O]⁺˙ ions in the mass spectra of diphenyl ether and diphenyl carbonate have the same structure, but one which differs from that of these ions from phenylphenol. [C₁₂H₉O]⁺ ions from all three compounds have isomerized to a common structure.     

3-Pyridylacetonitrile-ligated 11-vertex rhodathiaboranes: synthesis,characterization, and X-ray crystal structure

The reaction between the 11-vertex rhodathiaborane [8,8-(PPh₃)₂-nido-8,7-RhSB₉H₁₀] (1) and 3-pyridylacetonitrile affords the hydrorhodathiaborane [8,8,8-(PPh₃)₂H-9-(3-Py-CH₂CN)-nido-8,7-RhSB₉H₉] (2) in good yield. Treatment of this cluster with ethylene leads to the formation of red, [1,1-(PPh₃)(η²-C₂H₄)-3-(3-Py-CH₂CN)-closo-1,2-RhSB₉H₈] (3). Both 11-vertex polyhedral boron-based clusters have been characterized by multielement NMR spectroscopy. In addition, (3) has been analyzed by single-crystal X-ray diffraction analysis and is only the second ethylene-ligated metalla-heteroborane to be characterized in the solid state. The molecular structure of this cluster is based on an octadecahedron. In the crystal lattice, the individual clusters form layers supported by short edge-to-face π-interactions between the phenyl rings of neighboring molecules.     

有机锡9-芴酮-4-甲酸酯的合成、结构及抗癌活性

合成了3个有机锡9-芴酮-4-甲酸酯:三苯基锡9-芴酮-4-甲酸酯[(C₆H₅)₃Sn(C₁₄H₇O₃)](1)、三环己基锡9-芴酮-4-甲酸酯[(C₆H₁₁)₃Sn(C₁₄H₇O₃)](2)和三(2-甲基-2-苯基丙基)锡9-芴酮-4-甲酸酯[(C₆H₅C(CH₃)₂CH₂)₃Sn(C₁₄H₇O₃)](3)。通过元素分析、红外光谱、核磁共振谱(¹H、¹³C和¹¹⁹Sn)、热重分析进行了表征;用单晶X射线衍射方法测定了化合物的晶体结构,并对其进行了量子化学计算和体外抗...     

Total synthesis of the proposed structures of hyacinthacines C2, C3, and their C5-epimers

Synthesis and structural confirmation of highly oxygenated pyrrolizidine alkaloids, hyacinthacines C₂ [(1S,2R,3R,5R,7S,7aR)-3,5-hydroxymethyl-1,2,7-trihydroxypyrrolizidine], C₃[(1S,2R,3R,5S,7R,7aR)-3,5-hydroxymethyl-1,2,7-trihydroxypyrrolizidine], and their C5-epimers were achieved on the basis of the highly divergent method employing (S)-(−)-2-pyrrolidone-5-carboxylic acid as the starting material.     

HB9X9˙ and H2B9X9 (X = Cl,Br, I): Neutral closo-Nonaboranes in the Novel Series BnHn+1, and BnHn+2 – Syntheses,Ab Initio Calculations,and Electronic Structures

Chemical reduction of B₉X₉ (X = Cl, Br, I) with gaseous HI proceeds stepwise to give the neutral paramagnetic clusters HB₉X₉ ^· , and the corresponding diamagnetic clusters H₂B₉X₉. Together they comprise the first neutral derivatives in the series B_nH_n+1 and B_nH_n+2 with n = 9. The EPR spectra of the paramagnetic HB₉X₉ ^· (X = Cl, Br, I) in glassy frozen CH₂Cl₂ solutions showed increasing g anisotropy for the heavier halogen derivatives, illustrating significant halogen participation at the singly occupied MO due to the larger spin-orbit coupling contributions. Temperature dependent ¹H NMR spectra of H₂B₉X₉ (in CD₃CN, X = Cl, Br) indicate the presence of H₂B₉X₉, [HB₉X₉]^–, and [CD₃CNH]⁺ with H₂B₉X₉ acting as a Brønsted acid. The corresponding ¹¹B NMR spectra (in CD₃CN) show the presence of the dianions [B₉X₉]^2– as a result of the protonation of CD₃CN. The ¹¹B resonances of the species H₂B₉X₉ and [HB₉X₉]^– are obscured by superimposition of the two resonance lines of the dianions [B₉X₉]^2–. Temperature dependent ¹¹B{¹H} MAS-NMR spectra of H₂B₉Br₉ show coalescence at 410 K and hence dynamic behaviour of the neutral B₉-cluster in the solid. Cyclic voltammetry experiments of H₂B₉Br₉ in CH₃CN solvent) are compatible with the redox sequence [B₉Br₉]^2––[B₉Br₉] ^{· –}–B₉Br₉. Quantum chemical calculations with the electron localization function (ELF) are described.     

Structural and Anion Coordination Features of Macrocyclic Polyammonium Cations in the Solid,Solution and Computational Phases

Abstract

The crystal structures of two hexaaza macrocycles 1,4,7,12,15,18-hexaazacyclodocosane ([22]N₆:1-6H⁺, 6C1^?) and 1,13-dioxa-4,7,10,16,19,22-hexaazacyclotetraeicosane ([24]N₆O₂:2-6H⁺,6CI^?) as their hexa-hydrochloride salts have been determined. 1-6H⁺ binds specifically two CI^? anions above and below the almost planar hexaammonium macrocycle yielding a dinuclear CI^? complex. The hexacation 2-6H⁺ on the other hand interacts preferentially with three CI^? anions of the six present in the solid state. Among the three closest anions, one of them, interacting with four ammonium groups, is located in the centre of the macrocycle which adopts a “pocket-like” conformation. Potentiometric and ³⁵CI NMR experiments demonstrate that 2-6H⁺ also binds CI^? in aqueous solution. Subsequent extensive molecular dynamics computational studies starting from X-ray coordinates show that the solid state structure is representative of the solution conformations for I-6H⁺, whereas the conformations of 2-6H⁺ are strongly affected by intramolecular interactions between the ammonium centres and O-atoms of the ether linkage as well as by intermolecular interactions with H₂O molecules and CI^? counterions.     

Indene in a novel bonding mode in a carbonyl cluster: isolation,characterisation, and crystal and molecular structure of [HOs4(CO)9(C9H6)(C9H7)]

The reaction of [Os₃(CO)₁₂] with indene at 150°C under reflux affords the known compounds [H₂Os₃(CO)₉(C₉H₆)] (2) and [Os₄(CO)₁₂(C₉H₆)] (3). When the reaction temperature is increased to 170°C, the yield of 2 is greatly reduced, and a new tetraosmium cluster [HOs₄(CO)₉(C₉H₆)(C₉H₇)] (1) is isolated. An X-ray diffraction study of 1 has shown that one face of the Os₄ tetrahedron is capped by an indyne ligand coordinated in a μ₃-η²-− bonding mode, while the indenyl ligand (C₉H₇) is coordinated to a single Os atom in a η⁵ bonding mode through the five-membered ring.     

Proton-transfer salts of diphenylphosphinic acid with substituted 2-aminopyridine: crystal structure,spectroscopic and DFT studies

Three proton-transfer salts of diphenylphosphinic acid (DPPA) with 2-amino-5-(X)-pyridine (AMPY, X = Cl, CN or CH₃), namely, 2-amino-5-chloropyridinium diphenylphosphinate, C₅H₆ClN₂⁺·C₁₂H₁₀O₂P⁻ ( 1 , X = Cl), 2-amino-5-cyanopyridinium diphenylphosphinate, C₆H₆N₃⁺·C₁₂H₁₀O₂P⁻ ( 2 , X = CN), and 2-amino-5-methylpyridinium diphenylphosphinate, C₆H₉N₂⁺·C₁₂H₁₀O₂P⁻ ( 3 , X = CH₃), have been synthesized and characterized by FT–IR and ¹H NMR spectroscopy, and X-ray crystallography. The crystal structures of compounds 1 – 3 were determined in the space group P for 1 and 2 , and C2/c for 3 . All three compounds contain N—H…O hydrogen-bonding interactions due to proton transfer from the O=P—OH group of DPPA as donor to the pyridine N atom of AMPY as acceptor. The proton transfer of compounds 1 – 3 was also verified by ¹H NMR and FT–IR spectroscopy. The stoichiometry of all three proton-transfer salts was determined to be 1:1 and the Benesi–Hildebrand equation was applied to determine the formation constant (K_CT) and the molar extinction coefficient (ϵ_CT) in each case. Theoretical density functional theory (DFT) calculations were performed to investigate the optimized geometries, the molecular electrostatic potentials (MEP) and the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) of all three proton-transfer salts. The results showed good agreement between the experimental data and the DFT computational analysis.     

Nitrogen‐Rich Compounds of the Lanthanoids: The 5,5′‐Azobis[1H‐tetrazol‐1‐ides] of some Yttric Earths (Tb,Dy, Ho,Er, Tm,Yb, and Lu)

A set of N‐rich salts, 3 – 9 , of the heavy lanthanoids (terbium, 3 ; dysprosium, 4 ; holmium 5 ; erbium, 6 ; thulium, 7 ; ytterbium, 8 ; lutetium, 9 ) based on the energetic 5,5′‐azobis[1H‐tetrazole] (H₂ZT) was synthesized and characterized by elemental analysis, vibrational (IR and Raman) spectroscopy, and X‐ray structure determination. The synthesis of the lanthanoid salts 3 – 9 was performed by crystallization from concentrated aqueous solutions of disodium 5,5′‐azobis[1H‐tetrazol‐1‐ide] dihydrate (Na₂ZT?2 H₂O; 1 ) and the respective Ln(NO₃)₃?5 H₂O and yielded large rhombic crystals of the type [Ln(H₂O)₈]₂(ZT)₃?6 H₂O in ca. 70% of the theoretical yield. The compounds 3 – 9 are isostructural (triclinic space group P ) to the previously published yttrium salt 2 ; they show, however, a clear lanthanoid contraction of several crystallographic parameters, e.g., the cell volume or the Ln? O bond lengths of the Ln³⁺ ions and the coordinating H₂O molecules. The lanthanoid contraction influences the strengths of the H‐bonds, which can be observed as a red shift by 4 cm^?1 in the characteristic IR band, in particular from 3595 cm^?1 ( 3 ) to 3599 cm^?1 ( 9 ). In good agreement with previous works, 2 – 9 are purely salt‐like compounds without a coordinative bond between the tetrazolide anion and the Ln³⁺ cation.     

Indenylvanadium(V)‐Verbindungen. Darstellung,Struktur und NMR‐spektroskopische Untersuchungen

Indenylvanadium(V) Compounds Synthesis, Structure, and NMR Spectroscopic Studies Syntheses of the indenylvanadium(V)compounds are described: ^tC₄H₉N = V(η⁵‐C₉H₇)Cl₂ ( 1 ), ^tC₄H₉N = V(η⁵‐C₉H₇)Br₂ ( 2 ), ^tC₄H₉N = V(η⁵‐C₉H₇)(O^tC₄H₉)Cl ( 3 ), ^tC₄H₉N = V(η¹‐C₉H₇)(O^tC₄H₉)₂ ( 4 ), ^tC₄H₉N = V(η¹‐C₉H₇)₂(O^tC₄H₉) ( 5 ), ^tC₄H₉N = V(η¹‐C₉H₇)(η⁵‐C₅H₅) · (O^tC₄H₉) ( 6 ), ^tC₄H₉N = V(η¹‐C₉H₇)(η⁵‐C₅H₅)(NH^tC₄H₉) ( 7 ). All compounds were totally characterized by spectroscopic methods (MS; ¹H, ¹³C, ⁵¹V NMR), 3 by single crystal X‐ray diffraction. For 6 the presence of the diastereomeres RR/SS and RS/SR was shown by NMR spectroscopy. The chlorovanadate (IV) complex [NHC₄H₉]₂⁺[(^tC₄H₉N)₇V₇ · (μ‐Cl)₁₄Cl₂]^2– has been obtained by decomposition of 1 in solution; the crystal structure indicates a wheel structure with hydrogen bonds between the tert‐butylammonium cations and the complex anion.     

Synthesis,crystal structures,and luminescent properties of three cluster-based heterometallic and monometallic compounds

Two heterometallic cluster compounds and one monometallic cluster compound, namely [Ni₉Co₆(PMIDA)₆(BTC)₂(H₂O)₁₂]·6H₂O (1), [Co₁₃Zn₂(PMIDA)₆(H₂O)₁₈]·6NO₃·15H₂O (2), and [Fe₁₅(PMIDA)₆(BTC)₂(H₂O)₂₂]·38H₂O (3), have been obtained under hydrothermal conditions using N-(phosphonomethyl)imino-diacetic acid (H₄PMIDA) and 1,3,5-benzenetricarboxylate acid (H₃BTC) as ligands, and structurally characterized by X-ray crystallography. Compound 1 exhibits a 3D open framework constructed from [Ni₉Co₆(PMIDA)₆(H₂O)₁₂]⁶⁺ heteronuclear clusters and BTC^3? ligands. Compounds 2 and 3 are both zero-dimensional polynuclear clusters, further extended into 3D supramolecular structures via hydrogen-bonding interactions. However, there are some differences in their crystal structures; compound 2 features an isolated spherical heteronuclear cation cluster based on PMIDA^4? ligands, such that the NO₃ ^? anions only balance the charge, whereas compound 3 is characterized as a neutral monometallic cluster incorporating two different types of organic acid ligands, namely PMIDA^4? and BTC^3?, and the two BTC^3? ligands exhibit regular distribution in each cluster. The luminescence properties of all three compounds have been investigated at room temperature.     

Darstellung, 11B-NMR-, Schwingungsspektren und Kristallstruktur von [(C5H5N)2CH2][1-(O2N)B10H9]

Preparation, ¹¹B NMR, Vibrational Spectra, and Crystal Structure of [(C₅H₅N)₂CH₂][1-(O₂N)B₁₀H₉] By reaction of [B₁₀H₁₀]^2? in aqueous acetonitrile with a saturated solution of NO₂ in dichloromethane [1-(O₂N) · B₁₀H₉]^2? and [B₁₀H₉(NO)B₁₀H₉]^3? are formed which can be separated by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose from the starting compound. The X-ray structure determination of [(C₅H₅N)₂CH₂][1-(O₂N)B₁₀H₉] (triclinic, space group P1 , a = 7.1530(9), b = 8.3753(8), c = 15.198(2) Å, α = 96.00(1), β = 95.48(1), γ = 95.60(1)°, Z = 2) reveals the coordination of the NO₂ group via N with a B1? N distance of 1.535(5) Å and an O2? N? O1 angle of 119.3(3)°. The ¹¹B NMR spectrum exhibits the characteristic feature (1 : 1 : 4 : 4) of an apical monosubstituted B₁₀ cluster with a strong downfield shift of the ipso-B atom at +13.4 ppm. The IR and Raman spectra show strong NO stretching vibrations at 1381 und 1420 cm^?1.