Air-stable Crystals Research Articles

Partially Oxidized Purely Organic Zwitterionic Neutral Radical Conductor: Multi-step Phase Transitions and Crossover Caused by Intra- and Intermolecular Electronic Interactions.

Formation of a partially charge-transfer or partially oxidized/reduced state has been one of the most important requirements for the development of highly conducting molecular materials, such as organic metals and superconductors. This requirement has been fulfilled by combining appropriate electron-donor and acceptor molecules to construct multi-component molecular complexes/salts, such as (TTF+0.59)(TCNQ-0.59) and (BEDT-TTF+0.5)2X-, where TTF = tetrathiafulvalene, TCNQ = tetracyanoquinodimethane, BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, and X = monovalent inorganic anion. Here, we propose a methodology to fulfill this requirement by a single neutral molecule; namely, we have connected two TTF+0.5-type partially oxidized π-skeletons through a boron anion to design a purely organic zwitterionic neutral radical {[(PDT-TTF-Cat)2]+B-}•. This molecule was successfully obtained as air-stable crystals containing solvent tetrahydrofuran (THF) molecules. Measurements of electrical resistivity, magnetic susceptibility, and X-ray diffraction reveal that the partially oxidized state is certainly formed, which enables realization of a 3/4-filled electron band. Furthermore, this system has intramolecular charge degrees of freedom, attributable to the two TTF+0.5 π-skeletons introduced into the molecule. The resulting interplay of intra- and intermolecular charge degrees of freedom (or simply, intra- and intermolecular electronic interactions) has led to multi-step phase transitions and crossover, providing unique strongly correlated electron properties, such as the formation of a three-dimensional charge-ordered dimer-Mott insulating state and its melting triggered by disorder-order transformation of the co-crystallized solvent THF molecules at low temperatures.

Configurational landscape of chiral iron(ii) bis(phosphane) complexes.

The reaction of a chiral [FeH(η2-H2){(R,R)-Me-DuPhos}2]+ ((R,R)-Me-DuPhos = (-)-1,2-bis[(2R,5R)-2,5-dimethylphospholano]benzene) complex with ethers and halides is investigated by NMR techniques. From this study, it is apparent that dihydrogen ligand exchange by poorly-coordinating donor molecules, such as THF or Et2O, is feasible under mild conditions. The cis-[FeH(THF-d8){(R,R)-Me-DuPhos}2]+ complex is identified as the product in THF-d8 solution. A mixture of cis- and trans-[FeH(ether){(R,R)-Me-DuPhos}2]+ isomers is obtained after the addition of small quantities of THF or Et2O to a CD2Cl2 solution of [FeH(η2-H2){(R,R)-Me-DuPhos}2]+. The reaction of [FeH(η2-H2){(R,R)-Me-DuPhos}2]+ with an excess of iodide or chloride salts in THF-d8 or CD2Cl2 affords initially cis- and trans-[FeHX{(R,R)-Me-DuPhos}2] (X = Cl or I) isomers. The trans complex is the thermodynamic product obtained when X = Cl, whereas the cis isomer is obtained when X = I. These complexes evolve with time, and the pentacoordinated [FeX{(R,R)-Me-DuPhos}2](A) (X = Cl, A = BF4; X = A = I) and hexacoordinated trans-[FeCl2{(R,R)-Me-DuPhos}2] compounds are obtained as air-stable crystals and identified by X-ray diffraction and NMR techniques. Experiments done with (S,S)-Me-DuPhos ((+)-1,2-bis[(2S,5S)-2,5-dimethylphospholano]benzene) gave similar results, and the [FeI{(S,S)-Me-DuPhos}2](ClO4) compound has been crystallographically characterized.

Formulation of an Unprecedented Potassium Thiadiazolate Framework Via In-Situ Ligand Synthesis

The development of extended structures using s-block metal centres is fairly rare because of the predominance of ionic forces at metal center. The in-situ formation of 1,3,5-thiadiazole-2,5-dithiol ligand and its coordination to potassium metal ions results in the form of air stable green crystals of a novel framework [C2HKN2OS3]. The two-dimensional framework is characterized as P21 space group with the potassium ion, being heptacoordinated. The compound, showed distorted pentagonal bipyramidal coordination geometry due to the larger cationic radius of the potassium. The potassium metal ion is forming a bond with a nitrogen atom of azine nitrogens, two bonds with the oxygen atoms of the two hydroxyl ions and four bonds with the four sulfide ions of thiol moieties of four different thiadiazole rings. The C-S bond distances are in the range of 1.687(4) to 1.760(4) slightly shorter than the ideal value of 1.77 and#197; for a C(sp2)-S single bond. The thermogravimetric analysis indicates that a successive loss of the ligand occurs in the range of 253.06 oC to 357.53 oC that infers the stability of the compound.

Synthesis and Structure of Melamium Bromide C6N11H10Br and Melamium Iodide C6N11H10I

Melamium bromide and melamium iodide were synthesized from dicyandiamide in the presence of ammonium halides in evacuated Duran glass ampoules at temperatures of 450 °C. The crystal structures of both compounds were obtained from single‐crystal X‐ray diffraction. Melamium bromide C6N11H10Br crystallizes in space group P21/n [no. 14, a = 7.0500(5), b = 28.7096(18), c = 10.8783(8) Å, β = 96.060(2)°, Z = 8, wR2 = 0.2231] and exhibits a layer‐like arrangement of melamium ions, wherein both planar as well as twisted molecular structures of the cations occur. Melamium iodide C6N11H10I crystallizes in space group P21/c [no. 14, a = 6.8569(3), b = 11.9949(6), c = 14.0932(6) Å, β = 97.613(2)°, Z = 4, wR2 = 0.0654], however in a structure completely different from the one of melamium bromide. The melamium iodide structure is comprised of stacks of planar melamium ions that form complex, hydrogen‐bonded network layers with iodide ions within the layers. Both compounds were further characterized by FTIR spectroscopy, mass spectrometry, and elemental analyses. Melamium bromide and melamium iodide could be obtained as air stable and colorless crystals. Samples are crystallographically phase pure as shown by Rietveld refinement.

Hydrogen and halogen bonding in a concerted act of anion recognition: F⁻ induced atmospheric CO₂ uptake by an iodophenyl functionalized simple urea receptor.

Two simple urea based para-halo substituted [Iodo (L1) and Bromo (L2)] acyclic receptors have been extensively studied as a receptor for various anions. Receptors L1 efficiently uptake atmospheric CO2 and stabilize as air-stable crystals of HCO3(-) dimer (complex 1a) in the presence of n-tetrabutylammonium (n-TBA) fluoride through the simultaneous formation of hydrogen and halogen bonding, yielding a tetrahedrally surrounded non-covalent coordinated complex. However, receptor L2, in the presence of n-TBA salt of F(-), has been found to form a complex with the octahedral SiF6(2-) anion, where the coordination environment of the anion is merely governed by multiple N-H···F (anion) interactions. The fluoride induces an uptake of aerial CO2 only for L1, which is due to the unique ability of L1 to simultaneously form both hydrogen and halogen bonds with an anionic guest. The most decisive evidence supporting the ability of L1 to form a halogen bond is obtained via crystallizing the acetate complex of both the receptors. The receptor L1 stabilizes the acetate anion via both H-bonding and halogen bonding interactions, while the receptor L2 only forms H-bonding interactions with acetate anion. The solution-state anion binding properties of L1 and L2 have been investigated by qualitative and quantitative (1)H NMR titration experiments with halides and oxyanions in DMSO-d6. Both the receptors showed strong solution-state binding with F(-), HCO3(-) and CH3COO(-), as observed in the solid-state, whereas both of them have been found to be less interactive with other anions such as Cl(-), Br(-), I(-), NO3(-), HSO4(-), and H2PO4(-).

ChemInform Abstract: Synthesis and Photolysis of a 1,2-Disilathietane.

The reaction of tetramesityldisilene (1) with thiobenzophenone (2) gave the first disilathietane, 4,4-diphenyl-1,1,2,2-tetramesityl-1,2,3-disilathietane (3), as air-stable colorless crystals. Photolysis of 3 in the presence of ethanol afforded two compounds, dimesityl(diphenylmethyl) ethoxysilane (5) and dimesitylehoxysilanethiol (6); in the absence of ethanol photolysis gave the silene 1,1-dimesityl-2,2-diphenylsilene (7), in moderate yield

Synthesis of Oxygen- and Sulfur-Bridged Dirhodium Complexes and Their Use As Catalysts in the Chemoselective Hydrogenation of Alkenes

Oxygen-bridged and sulfur-bridged rhodium homobimetallic complexes were synthesized as air-stable crystals by using 2,6-bis(phosphanylmethyl)phenolate and -thiophenolate as the ligands, respectively. The oxygen-bridged dirhodium complex has a symmetrical structure where the carbon atom at the ipso position, oxygen, and two rhodium atoms are located in the same plane. It is thermally stable compared to the sulfur-bridged dirhodium complex and shows catalytic activity for hydrogenation of alkenes with high chemoselectivity.

Three‐Dimensional Intramolecular Exchange Interaction in a Curved and Nonalternant π‐Conjugated System: Corannulene with Two Phenoxyl Radicals

A neutral diradical based on corannulene with curved and nonalternant π conjugation has been synthesized and isolated as air-stable crystals. Sizable spin delocalization and strong intramolecular exchange interaction in the intrinsically three-dimensional π network (see picture), as well as significant diradical contributions in the ground state, were experimentally disclosed.

Synthese und Kristallstruktur von heteronuklearen Metallkomplexen mit Nitridobrücken Re≡N‐Ni, Re≡N‐Pt, Os≡N‐Rh und Os≡N‐Ir

AbstractSynthesis and Crystal Structure of Heteronuclear Metal Complexes with Nitrido Bridges Re≡N‐Ni, Re≡N‐Pt, Os≡N‐Rh, and Os≡N‐IrThe heteronuclear complex [(Me2PhP)3Br2Re≡N‐NiBr2(OPMe2Ph)] (1) is obtained by the reaction of [ReNBr2(PMe2Ph)3] with NiBr2 in tetrahydrofuran in form of dark green, air sensitive crystals crystallizing in the monoclinic space group P21/n with a = 961.44(9), b = 3692.6(4), c = 1177.8(2) pm, β = 103.42(1)°, and Z = 4. In the dinuclear complex the complex fragment [NiBr2(OPMe2Ph)] is connected by an asymmetric nitrido bridge Re≡N‐Ni with the nitrido complex [ReNBr2(PMe2Ph)3], such that the Ni atom achieves a tetrahedral coordination. The nitrido bridge is characterized by a bond angle Re‐N‐Ni of 172.7(7)° and distances Re‐N = 169(1) and Ni‐N = 195.0(9) pm.The reaction of [ReNCl2(PMe2Ph)3] with PtCl4 in THF proceeds under reduction of PtIV to yield air stable, brown crystals of [{(Me2PhP)3Cl2Re≡N}2PtCl2] (2) with the monoclinic space group P21/c and a = 1241.3(1), b = 1734.0(1), c = 1369.7(1) pm, β = 101.32(1)°, and Z = 2. The divalent Pt atom exhibits a square planar coordination with the two rhenium(V) nitrido complexes coordinated by nitrido bridges Re≡N‐Pt in trans position. The distances in the virtually linear nitrido bridge (Re‐N‐Pt = 174.0(3)°) are Re‐N = 170.6(5) pm and Pt‐N = 196.4(5) pm.The nitrido complex [OsNCl3(AsPh3)2] reacts with [Rh(μ‐Cl)(COD)]2 in CH2Cl2 to yield [(Ph3As)2Cl3Os≡N‐RhCl(COD)] (3). The heterometallic complex forms olive green, largely air stable crystals with the monoclinic space group Cc and a = 2316.8(5), b = 1169.3(1), c = 1601.4(2) pm, β = 106.12(1)°, and Z = 4. Rh(I) exhibits a square‐planar coordination with the two π bonds of the COD ligand coordinating in cis position. The osmium nitrido complex is coordinated by a linear nitrido bridge Os≡N‐Rh (Os‐N‐Rh = 176.1(7)°) with distances Os‐N = 168(1) pm and Rh‐N = 186(1) pm.The complex [(Ph3As)2Cl3Os≡N‐IrCl(COD)] (4) is obtained by the reaction of [Ir(μ‐Cl)(COD)]2 with [OsNCl3(AsPh3)2] in CH2Cl2. 4 crystallizes isotypic to 3 in form of olive brown blocks with the space group Cc and a = 2322.1(2), b = 1167.01(6), c = 1603.8(2) pm, β = 105.927(9)°, and Z = 4. The nitrido bridge Os≡N‐Ir is characterized by the bond angle Os‐N‐Ir = 176.2(8)° and distances Os‐N = 171.2(8) pm and Ir‐N = 181.5(8) pm.

Structural modulation of molybdenyl iodate architectures by alkali metal cations in AMoO3(IO3) (A = K, Rb, Cs): a facile route to new polar materials with large SHG responses.

Three new molybdenyl iodates, KMoO3(IO3) (1), RbMoO3(IO3) (2), and CsMoO3(IO3) (3), have been prepared through the hydrothermal reactions of MoO3 with AIO4 (A = K, Rb, or Cs) at 180 C. These compounds are isolated as nearly colorless, air-stable crystals. Single-crystal X-ray diffraction experiments reveal that 1 possesses a corrugated layered structure constructed from molybdenum oxide chains that are bridged by iodate anions. The puckering of the layers is caused by the alignment of bent molybdenyl (MoO2(2+)) groups along one side of the molybdenum oxide chains. The K+ cations separate these layers from one another and serve to balance charge. In contrast, compounds 2 and 3, which are isostructural, form three-dimensional structures with small cavities filled with Rb+ or Cs+ cations. The differences between the structures of 1 and those of 2 and 3 are due to rotation of the molybdenyl units as translation occurs down the molybdenum oxide chains in order to accommodate the increased size of the Rb+ and Cs+ cations. This rotation allows for the iodate anions to bridge the molybdenum oxide chains in an additional dimension, creating a three-dimensional network structure. Furthermore, while 1 crystallizes in a centrosymmetric space group, 2 and 3 crystallize in polar space groups. Second-harmonic generation measurements on 2 and 3 show large responses of 400x alpha-quartz. Differential scanning calorimetry measurements demonstrate that 2 and 3 are thermally stable to 494 and 486 C, respectively. UV-vis diffuse reflectance spectra of these compounds show a high degree of transparency from 1 to 3 eV and a band gap of 3.1 eV.

Modular Construction of A1+xM4-2xM‘7+xSe15 (A = K, Rb; M = Pb, Sn; M‘ = Bi, Sb): A New Class of Solid State Quaternary Thermoelectric Compounds

Five isostructural compounds, K1.25Pb3.5Bi7.25Se15 (I), K1.46Sn3.09Bi7.45Se15 (II), Rb1.45Pb3.1Sb7.45Se15 (III), K1.45Pb3.1Sb7.45Se15 (IV), and K2.15Pb1.7Sb8.15Se15 (V) were prepared by the molten flux method as silver rodlike air-stable crystals. They all crystallize in the monoclinic space group P21/m with a = 17.4481(8) A, b = 4.1964(2) A, c = 21.695(1) A, β = 98.850(1)° for I, a = 17.454(5) A, b = 4.201(1) A, c = 21.760(6) A, β = 98.550(5)° for II, a = 17.3160(7) A, b = 4.1406(2) A, c = 21.6401(8) A, β = 99.139(1)° for III, a = 17.1204(6) A, b = 4.1568(2) A, c = 21.6362(8) A, β = 98.706(1)° for IV, and a = 17.167(4) A, b = 4.1494(9) A, c = 21.684(5) A, β = 98.664(3)° for V (Z = 2 for all compounds). The general formula A1+xM4-2xM‘7+xSe15 (A = K, Rb; M = Pb, Sn; M‘ = Bi, Sb) is derived from a large degree of variability in composition that is expressed in terms of mixed occupancy among A+, M2+, and M‘3+ atoms. The structure type has a three-dimensional framework assembled from NaCl- and Bi2Te3-type mod...

Air-stable crystalline primary phosphines and germanes: synthesis and crystal structures of dibenzobarellenephosphine and tribenzobarellenegermane

The syntheses of dibenzobarellenephosphine and tribenzobarellenegermane are described; at room temperature these primary phosphines and germanes form air-stable crystals whose structures are reported together with that of tribenzobarellenemethane.

The Syntheses of [M(C5Ph5)2]n+ (N=0,1) Complexes of Nickel, Iron and Chromium. The Structures of the Decaphenylmetallocenium Cations of Nickel and Iron

Decaphenylnickelocene is isolated from the reaction between [Ni(CO)2(PPh3)2], 5-bromo-1,2,3,4,5-pentaphenylcyclopenta-1,3-diene and zinc dust. Decaphenylnickelocene is obtained as air-stable crystals, insoluble in most common solvents. It can be oxidized by bromine or by nitronium tetrafluoroborate to the decaphenylnickelocenium cation, which can be chemically reduced to decaphenylnickelocene. The decaphenylnickelocenium cation is characterized spectroscopically and its crystal structure, as its tribromide and tetrafluoroborate salts, is reported. The structures are compared with that of decaphenylferrocenium tribromide, which is formed by bromine oxidation of decaphenylferrocene. Decaphenylchromocenium tribromide is prepared by bromine oxidation of decaphenylchromocene, which is prepared from [Cr(MeCN)3(CO)3], pentaphenylcyclopentadienyl bromide and zinc dust.

N,N-Disubstituierte Nʹ-Ferrocenoylthioharnstoffe als zweizähnige Komplexliganden für Übergangsmetallionen. Kristallstruktur von Bis-(N,N-diethyl-Nʹ-ferrocenoylthioureato)nickel(II) / N,N-Disubstituted Nʹ-Ferrocenoyl Thioureas as Bidentate Ligands for Transition Metal Ions. Crystal Structure of Bis-(N,N-diethyl-Nʹ-ferrocenoylthioureato)nickel(II)

N,N-diethyl-Nʹ-ferrocenoyl-thiourea and N-(morpholino-thiocarbonyl)ferrocenecarboxylic amide have been prepared by the reaction of ferrocenoyl chloride with potassium thiocyanate and the respective amine in dry acetone. These bidentate ligands yield neutral heterometalIic complexes with Ni(II), Cu(II), Mn(II) and Co(III). The dark brown air stable crystals of bis-(N,N-diethyl-Nʹ-ferrocenoylthioureato)nickel(II) were characterized by X-ray structure de­termination. Lattice dimensions: a = 1870.9(1), 6= 1161.5(1), c = 1491.4(1) pm; space group Pca21, Z = 4, R = 0.030 for 5707 observed reflections.

A Straightforward Synthesis of Nitrilimines; X‐Ray Crystal Structure of a Nitrilimine Stabilized by Non‐Heteroatom Substituents

Air-stable crystals of bis(triphenylmethyl)-substituted nitrilimine 3 are produced in 90% yield from the reaction of bis(trimethylstannyl)diazomethane 1 with triphenylmethyl chloride. The stability of 3 can only be explained by steric effects, since the electronic interaction of the Ph3C substituents with the CNN frame is not evident. Compound 3 reacts as a 1,3-dipole.

Notizen: 3-Diethylamino-5-phenyl-1,2,4-dithiazolium-hexachlorodicuprat(II) und -tetrachlorocuprat(II), (dpd)2Cu2Cl6 und (dpd)2CuCl4 / 3-Diethylamino-5-phenyl-1,2,4-dithiazolium Hexachlorodicuprates(II) and Tetrachlorocuprates(II), (dpd)2Cu2Cl6 and (dpd)2CuCl4

(dpd)2Cu2Cl6 has been prepared by the reaction of bis(1,1-diethyl-3-benzoyl-thioureato)-copper(II) with SOCl2 in nitromethane. The brown air stable crystals were characterized by X-ray structure determination. Space group P21/n, Z = 4, 4222 observed unique reflexions, R = 0.053, Lattice dimensions (22 °C): a = 1336.4(2), b = 1677.2(9), c = 749.3(2) pm; β = 92.46(2)°. Similar reaction in acetonitrile yields stable orange crystals of (dpd)2CuCl4.

Trifluormethylisocyanidkomplexe des chroms, molydäns und wolframs, hexakis(trifluormethylisocyanid)chrom

Tricarbonyl-tris(trifluoromethyl isocyanide)molybdenum ( 3a) and -tungsten ( 3b) are formed upon reaction of trifluoromethyl isocyanide ( 1) with tricarbonyl(η 6-cycloheptatrien)molydenum ( 2a) and -tungsten ( 2b), respectively. The NMR spectra indicate that these compounds are formed as the meridial isomers. Photolysis of 3a and 3b in the presence of 1 yields unseparable mixtures of the compounds (CO) x M(CNCF 3) 6− x . The homoleptic trifluoromethyl isocyanide complex hexakis(trifluoromethyl isocyanide)chromium ( 5) has been synthesized in low yields by reaction of tris(η 3-allyl)chromium ( 4) with 1. The yellow air-stable crystals of 5 possess a high vapour pressure at ambient temperature, and are thermally stable up to 180°C. The structure of 5 has been determined by an X-ray diffraction study.

Polyhedral metallacarbaborane chemistry: preparation, molecular structure, and nuclear magnetic resonance investigation of [3-(η5-C5Me5)-closo-3,1,2-MC2B9H11] (M = Rh or Ir)

Reaction between Cs[nido-7,8-C2B9H11] and [{M(η5-C5Me5)Cl2}2] (M = Rh or Ir) yielded orange-yellow, air-stable crystals of [3-(η5-C5Me5)-closo-3,1,2-RhC2B9H11] [compound (2), 34%] or [3-(η5-C5Me5)-closo-3,1,2-IrC2B9H11] [compound (3), 96%] both of which were characterized by their assigned 11B and 1H n.m.r. spectra and by single-crystal X-ray diffraction analyses. Crystals of (2) were orthorhombic, space group P212121, with a = 1 081.0(2), b = 1 278.2(1), c = 1 278.4(2) pm, and Z = 4; R = 0.0197, R′ = 0.0204 for 1 756 observed reflections [I > 2.0σ(I)]. Crystals of (3) were also orthorhombic, space group P212121, with a = 1 076.3(1), b = 1 282.9(1), c = 1 292.8(2) pm, and Z = 4; R = 0.0286, R′ = 0.0307, for 1 712 observed reflections [I > 2.0σ(I)]. The n.m.r. properties of the C2B9H11 fragments of (2) and (3) are compared with the 11B and hitherto unreported 1H n.m.r. characteristics of the corresponding fragments of [3-(η5-C5H5)-closo-3,1,2-CoC2B9H11] (4), closo-1,2-C2B10H12, nido-7,8-C2B9H13, and [nido-7,8-C2B9H12]−, in order to assess any n.m.r. shielding patterns that might reveal bonding trends. The unique endo/bridging open-face hydrogen atom in [nido-7,8-C2B9H12]− is discussed in the light of its n.m.r. properties.

Synthese von zweikernigen Triazenido- und Pentaazadienidokomplexen des einwertigen Silbers. Kristallstruktur von [Ag(MeOC6H4N3C6H4OM e)]2· 2/3 Py, [Ag(MeOC6H4N5C6H4OMe)]2 und [Ag(EtOC6H4N5C6H4OEt)]2 · Py / Dimeric Triazenido and Pentaazadienido Complexes of Monovalent Silver. Synthesis and Structure of [Ag(MeOC6H4N3C6H4OM e)]2· 2/3 Pyridine, [Ag(MeOC6H4N5C6H4OMe)]2 und [Ag(EtOC6H4N5C6H4OEt)]2 · Pyridine

[Ag(MeOC6H4N3C6H4OMe)]2 (1) is formed in THF from AgNO3 , and the triazenide anion, as obtained from the corresponding triazene and Na. 1 crystallizes from pyridine in the form of orange-yellow , air stable crystals with the com position 1·2/3 C5H5N: space group P 1̅ with a = 1468.0(5), b = 1514.1(6), c - 1316.1(3) pm, a = 113.45(3)°, β = 1 1 4 .8 1 (2 )°, γ = 66.78(3)°, Z - 3. The triazenide ion functions as a bridging ligand forming planar (AgN3)2 heterocycles. The unit cell contains two symmetry-independent dinuclear complexes, one of which is centrosymmetrical. The short Ag -Ag distances of 268.0 and 269.8 pm suggest Ag -Ag bonding. The pentaazadienido complexes Ag(RN5R) with R = p -MeO - C6H4 (2), p -EtO - C6H4 (3), p-Cl -C6H4 (4), p -F -C6H4 (5), are obtained from saturated solutions of the pentaazadiene in conc. NH3 and AgNO3 , as explosive, red precipitates which are stable in air. Crystals of 2 and 3 · C5H5N are obtained from pyridine. 2 crystallizes in the monoclinic space group P21/c: a - 583.7(6), b = 1705.1(9), c = 1489.6(9) pm. β = 96.2(1)°, Z = 2; 3 · C5H5N is triclinic (space group P 1̅) with a = 1160.4(4). b = 1671.0(6), c = 509.0(1) pm. a = 97.51(2)°, β = 97.36(2)°, γ = 81.51(3)°, Z = 1. The complexes 2 and 3 are dinuclear with the pentaazadienide ion as a (N1)-η1,(N5)-η1 bridging ligand in 2 and a (N1)-η1, (N3)-η1 bridging ligand in 3. The bridging mode in 3 results in a short Ag -Ag contact of 283.44 pm. The Ag -N distances range from 210.8 to 215.7 pm in 1 and from 215.0 to 220 pm in (2) and (3).

Titanium(0) Arene Complexes: Synthesis and X‐ray Crystal Structure of [η6‐C10H8Ti{tBuSi(CH2PMe2)3}

An unusually strong metal-arene back-bonding characterizes the bonding in the title complex 1, which is obtained in the form of deep purple-red, air-stable crystals on reduction of [TiCl3(trimpsi)(thf)], trimpsi = tBuSi(CH2PMe2)3, with naphthalenesodium in THF. This 16e-complex has an overall three-legged piano-stool geometry, and the π-bonded naphthalenring has partial dienediyl character.