An Accurate Molecular Structure of Phenyl,the Simplest Aryl Radical

The phenyl radical (C₆H₅^.) is the prototypical σ‐type aryl radical and one of the most common aromatic building blocks for larger ring molecules. Using a combination of rotational spectroscopy of singly substituted isotopic species and vibrational corrections calculated theoretically, an extremely accurate molecular structure has been determined. Relative to benzene, the phenyl radical has a substantially larger C‐C_ipso‐C bond angle [125.8(3)° vs. 120°], and a shorter distance [2.713(3) Å vs. 2.783(2) Å] between the ipso and para carbon atoms.     

Synthesis,Spectroscopic, and X‐Ray Diffraction Studies of cis‐Dichlorobis(4‐propanoyl‐2,4‐dihydro‐5‐methyl‐2‐phenyl3 H‐pyrazol‐3‐onato) Tin(IV)

Reaction between an aqueous ethanol solution of tin(II) chloride and that of 4‐propanoyl‐2,4‐dihydro‐5‐methyl‐2‐phenyl‐3 H‐pyrazol‐3‐one in the presence of O₂ gave the compound cis‐dichlorobis(4‐propanoyl‐2,4‐dihydro‐5‐methyl‐2‐phenyl‐3 H‐pyrazol‐3‐onato) tin(IV) [(C₂₆H₂₆N₄O₄)SnCl₂]. The compound has a six‐coordinated Sn^IV centre in a distorted octahedral configuration with two chloro ligands in cis position. The tin atom is also at a pseudo two‐fold axis of inversion for both the ligand anions and the two cis‐chloro ligands. The orange compound crystallizes in the triclinic space group P 1 with unit cell dimensions, a = 8.741(3) Å, b = 12.325(7) Å, c = 13.922(7) Å; α = 71.59(4), β = 79.39(3), γ = 75.18(4); Z = 2 and D_x = 1.575 g cm^–3. The important bond distances in the chelate ring are Sn–O [2.041 to 2.103 Å], Sn–Cl [2.347 to 2.351 Å], C–O [1.261 to 1.289 Å] and C–C [1.401 Å] the bond angles are O–Sn–O 82.6 to 87.7° and Cl–Sn–Cl 97.59°. The UV, IR, ¹H NMR and ¹¹⁹Sn Mössbauer spectral data of the compound are reported and discussed.     

The seven‐membered nickelacycle [NiBr{o‐CH=C(CF3)C6H4CH2PPh2‐κ2C,P}{PPh(CH2Ph)2}]

The crystal and molecular structures of the title compound, 3‐bromo‐3‐(di­benzyl­phenyl­phospho­nio)‐2,2‐di­phenyl‐5‐trifluoromethyl‐1H‐benzo­[e][1,2]­phosphanickelepine, [NiBr(C₂₂H₁₇F₃P)(C₂₀H₁₉P)], which was obtained as the major regioisomer from insertion of HCCCF₃ into the Ni—C bond of the five‐membered phosphanickelacycle [NiBr(o‐C₆H₄CH₂PPh₂‐κ²C,P){PPh(CH₂Ph)₂}], have been determined. Principal geometric data include the Ni—X bond lengths Ni—Br 2.3343 (4) Å, Ni—P 2.1867 (7) and 2.2094 (7) Å, and Ni—C 1.882 (3) Å, and the two trans angles P—Ni—P 171.55 (3)° and Br—Ni—C 176.88 (9)°.     

A ruthenium(II)–porphyrin–carbene complex with a weakly bonded methanol ligand

The title di­phenyl­carbene porphyrin complex (di­phenyl­carbenyl‐κC)(methanol‐κO)(5,10,15,20‐tetra‐p‐tolyl­por­phy­rin­ato‐κ⁴N)ruthenium(II) methanol solvate, [Ru­(C₁₃H₁₀)(C₄₈H₃₆N₄)(CH₄O)]·CH₄O, has a six‐coordinate Ru atom with a methanol mol­ecule as the second axial ligand. The carbene fragment is slightly distorted from an ideal sp² configuration, with a C(phenyl)—C(carbene)—C(phenyl) angle of 112.2 (3)°. The Ru—C bond length of 1.845 (3) Å is comparable with other carbene complexes. The two phenyl rings of the carbene ligand are perpendicular to the carbene plane. Methanol solvate mol­ecules link the methanol ligands of adjacent porphyrin complexes via hydrogen bonds.     

Two trans‐4‐aminoazoxybenzenes

Two isomeric trans‐4‐amino­azoxy­benzenes, trans‐1‐(4‐amino­phenyl)‐2‐phenyl­diazene 2‐oxide (α, C₁₂H₁₁N₃O) and trans‐2‐(4‐amino­phenyl)‐1‐phenyl­diazene 2‐oxide (β, C₁₂H₁₁N₃O), have been characterized by X‐ray diffraction. The α isomer is almost planar, having torsion angles along the C_aryl—N bonds of only 4.9 (2) and 8.0 (2)°. The relatively short C_aryl—N bond to the non‐oxidized site of the azoxy group [1.401 (2) Å], together with the significant quinoid deformation of the respective phenyl ring, is evidence of conjugation between the aromatic sextet and the π‐electron system of the azoxy group. The geometry of the β isomer is different. The non‐substituted phenyl ring is twisted with respect to the NNO plane by ca 50°, whereas the substituted ring is almost coplanar with the NNO plane. The non‐oxidized N atom in the β isomer has increased sp³ character, which leads to a decrease in the N—N—C bond angle to 116.8 (2)°, in contrast with 120.9 (1)° for the α isomer. The deformation of the C—C—C angles (1–2°) in the phenyl rings at the substitution positions is evidence of the different character of the oxidized and non‐oxidized N atoms of the azoxy group. In the crystal structures, mol­ecules of both isomers are arranged in chains connected by weak N—H?O (α and β) and N—H?N (β) hydrogen bonds.     

cis‐Di­phenyl­bis(1,3,5‐tri­aza‐7‐phospha­adamantane‐κP)platinum(II)

The structure of the title compound, [Pt(C₆H₅)₂(C₆H₁₂N₃P)₂] or [Pt(Ph)₂(PTA)₂] (where Ph is phenyl and PTA is 1,3,5‐tri­aza‐7‐phosphaadamantane), is discussed. Selected geom­etric parameters are: Pt—P = 2.2888 (16) and 2.2944 (17) Å, Pt—C = 2.052 (5) and 2.064 (6) Å, C—Pt—C = 84.6 (2)° and P—Pt—P = 99.28 (6)°. The effective cone angle for the PTA ligands was calculated as 113°.     

Bis{2‐[(phenylimino)ethyl]‐1H‐pyrrol‐1‐ido‐κ2N,N′}nickel(II): a supramolecular structure formed by C—H...π hydrogen bonds

In the title compound, [Ni(C₁₂H₁₁N₂)₂], the Ni^II cation lies on an inversion centre and has a square‐planar coordination geometry. This transition metal complex is composed of two deprotonated N,N′‐bidentate 2‐[(phenylimino)ethyl]‐1H‐pyrrol‐1‐ide ligands around a central Ni^II cation, with the pyrrolide rings and imine groups lying trans to each other. The Ni—N bond lengths range from 1.894 (3) to 1.939 (2) Å and the bite angle is 83.13 (11)°. The Ni—N(pyrrolide) bond is substantially shorter than the Ni—N(imino) bond. The planes of the phenyl rings make a dihedral angle of 78.79 (9)° with respect to the central NiN₄ plane. The molecules are linked into simple chains by an intermolecular C—H...π interaction involving a phenyl β‐C atom as donor. Intramolecular C—H...π interactions are also present.     

2‐Imino‐3‐allyl‐benzothiazole as a π‐Ligand: Synthesis and Crystal Structure of [(CuCl)C10H10SN2], [C10H11SN2+]2[Cu2Cl4]2−, and [C10H11SN2+]2[Cu2Br4]2− π‐Compounds

The reaction of 2‐amino‐benzothiazole with allyl bromide resulted in a mixture of 2‐imino‐3‐allyl‐benzothiazole and 2‐imino‐3‐allyl‐benzothiazolium bromide.Using such a mixture and copper(II) chloride in acetonitrile solution in alternating‐current electrochemical synthesis crystals of the [(CuCl)C₁₀H₁₀SN₂] ( I ) have been obtained. The same procedure, performed in ethanol solution, has led to formation of [C₁₀H₁₁SN₂⁺]₂[Cu₂Cl₄]^2? ( II ). In the same manner the bromine derivative [C₁₀H₁₁SN₂⁺]₂[Cu₂Br₄]^2? ( III ) has been synthesized. All three compounds were X‐ray structurally investigated. I :monoclinic space group P2₁/n, a = 13.789(6), b = 6.297(3), c = 13.830(6) Å, β = 112.975(4)°, V = 1105.6 (9) ų, Z = 4 for CuCl·C₁₀H₁₀ SN₂ composition. Compounds II and III are isomorphous and crystallize in triclinic space group. II a = 7.377(3), b = 8.506(3), c = 9.998(4) Å, α = 79.892(10)°, β = 82.704(13)°, γ = 78.206(12)°, V = 601.9(4) ų, Z = 1. III a = 7.329(2), b = 8.766(3), c = 10.265(3) Å, α = 79.253(9)°, β = 82.625(9)°, γ = 77.963(9)°, V = 630.9(3) ų, Z = 1. In the structure I [(CuCl)C₁₀H₁₀SN₂] building blocks are bound into infinitive spiral‐like chains via strong N‐H..Cl hydrogen bonds. In the zwitter‐ionic II and III compounds copper and halide atoms form centrosymmetric [Cu₂X₄]^2? anions, which are interconnected via N‐H..X hydrogen bonds into infinite butterfly‐like chains. The strongest Cu‐(C=C) π‐interaction has been observed in structure I , where copper possesses coordination number 3. Increasing copper coordination number to 4 in II as well as replacing chlorine atoms by bromine ones in III suppresses markedly this interaction.     

Three N2‐benzoyl­oxybenz­amidines: sheet structures built from hard and soft hydrogen bonds and aromatic π–π stacking interactions

Molecules of the title compounds N²‐(benzoyl­oxy)­benz­ami­dine, C₁₄H₁₂N₂O₂, (I), N²‐(2‐hydroxy­benzoyl­oxy)­benz­ami­dine, C₁₄H₁₂N₂O₃, (II), and N²‐benzoyloxy‐2‐hydroxybenzamidine, C₁₄H₁₂N₂O₃, (III), all have extended chain conformations, with the aryl groups remote from one another. In (I), the mol­ecules are linked into chains by a single N—H⋯N hydrogen bond [H⋯N = 2.15 Å, N⋯N = 3.029 (2) Å and N—H⋯N = 153°] and these chains are linked into sheets by means of aromatic π–π stacking interactions. There is one intramolecular O—H⋯O hydrogen bond in (II), and a combination of one three‐centre N—H⋯(N,O) hydrogen bond [H⋯N = 2.46 Å, H⋯O = 2.31 Å, N⋯N = 3.190 (2) Å, N⋯O = 3.146 (2) Å, N—H⋯N = 138° and N—H⋯O = 154°] and one two‐centre C—H⋯O hydrogen bond [H⋯O = 2.46 Å, C⋯O = 3.405 (2) Å and C—H⋯O = 173°] links the mol­ecules into sheets. In (III), an intramolecular O—H⋯N hydrogen bond and two N—H⋯O hydrogen bonds [H⋯O = 2.26 and 2.10 Å, N⋯O = 2.975 (2) and 2.954 (2) Å, and N—H⋯O = 138 and 163°] link the molecules into sheets.     

4,4′‐Tri­methyl­enedipyridinium bis­[carboxy­methyl­phos­pho­nate(1–)]: a three‐dimensional framework structure built from O—H⃛O,N—H⃛O and C—H⃛O hydrogen bonds

In the title compound, C₁₃H₁₆N₂²⁺·2C₂H₄O₅P⁻, the cation lies across a twofold rotation axis in space group Fdd2. The anions are linked into molecular ladders by two O—H⃛O hydrogen bonds [H⃛O = 1.73 and 1.77 Å, O⃛O = 2.538 (2) and 2.598 (3) Å, and O—H⃛O = 160 and 170°], these ladders are linked into sheets by a single type of N—H⃛O hydrogen bond [H⃛O = 1.75 Å, N⃛O = 2.624 (3) Å and N—H⃛O = 171°] and the sheets are linked into a three‐dimensional framework by a single type of C—H⃛O hydrogen bond [H⃛O = 2.48 Å, C⃛O = 3.419 (4) Å and C—H⃛O = 167°].     

The effect of molecular planarity on crystal non‐centrosymmetry in benzyl­idene–aniline derivatives

In the title compound, N‐(2‐methoxy­phenyl)‐4‐nitro­benzyli­deneamine, C₁₄H₁₂N₂O₃, the two phenyl rings make a dihedral angle of 48.0 (2)° and the nitro group is at an angle of 6.5 (1)° with respect to its attached phenyl ring. In the crystal structure, mol­ecules are related as centrosymmetric pairs through π–π interactions and are further connected through strong C—H?O hydrogen bonds [C?O 3.4259 (17) Å and C—H?O 167°], forming molecular stacks along [100]. These stacks associate further through longer C—H?O interactions, forming two‐dimensional networks. In the c direction, there are only weak van der Waals interactions. The relationship between the molecular planarity and its centrosymmetry is also briefly described.     

Adducts of 1,1,1‐tris(4‐hydroxyphenyl)ethane with diamines: three‐dimensional hydrogen‐bonded frameworks formed with 1,6‐diaminohexane and 2,2′‐bipyridyl

The adduct 1,6‐di­amino­hexane–1,1,1‐tris(4‐hydroxy­phenyl)­ethane (1/2) is a salt {hexane‐1,6‐diyldiammonium–4‐[1,1‐bis(4‐hydroxyphenyl)ethyl]phenolate (1/2)}, C₆H₁₈N₂²⁺·2C₂₀H₁₇O₃^?, in which the cation lies across a centre of inversion in space group P. The anions are linked by two short O—H?O hydrogen bonds [H?O 1.74 and 1.76 Å, O?O 2.5702 (12) and 2.5855 (12) Å, and O—H?O 168 and 169°] into a chain containing two types of R(24) ring. Each cation is linked to four different anion chains by three N—H?O hydrogen bonds [H?O 1.76–2.06 Å, N?O 2.6749 (14)–2.9159 (14) Å and N—H?O 156–172°]. In the adduct 2,2′‐bipyridyl–1,1,1‐tris(4‐hydroxy­phenyl)­ethane (1/2), C₁₀H₈N₂·2C₂₀H₁₈O₃, the neutral di­amine lies across a centre of inversion in space group P2₁/n. The tris­(phenol) mol­ecules are linked by two O—H?O hydrogen bonds [H?O both 1.90 Å, O?O 2.7303 (14) and 2.7415 (15) Å, and O—H?O 173 and 176°] into sheets built from R(38) rings. Pairs of tris­(phenol) sheets are linked via the di­amine by means of a single O—H?N hydrogen bond [H?N 1.97 Å, O?N 2.7833 (16) Å and O—H?N 163°].     

Hydro­gen‐bond networks in tris(4‐hydroxy­phenyl)­methane and its 1:1 molecular complex with 4,4′‐bi­pyridine

In tris(4‐hydroxy­phenyl)­methane (or 4,4′,4′′‐methane­triyl­tri­phenol), C₁₉H₁₆O₃, mol­ecules are connected by O—H⃛O hydrogen bonds [O⃛O = 2.662 (2) and 2.648 (2) Å] into two‐dimensional square networks that are twofold interpenetrated. In tris(4‐hydroxy­phenyl)­methane–4,4′‐bi­pyridine (1/1), C₁₉H₁₆O₃·C₁₀H₈N₂, trisphenol mol­ecules form rectangular networks via O—H⃛O [O⃛O = 2.694 (3) Å] and C—H⃛O [C⃛O = 3.384 (3) Å] hydrogen bonds. Bi­pyridine mol­ecules hydrogen bonded to phenol moieties [O⃛N = 2.622 (3) and 2.764 (3) Å] fill the voids to complete the structure.     

1,6‐Interactions between di­methyl­amino and aldehyde groups in two bi­phenyl derivatives

The title compounds, 2‐(di­methyl­amino)­bi­phenyl‐2′‐carbox­aldehyde, C₁₅H₁₅NO, and 2‐(di­methyl­amino)­bi­phenyl‐2′,6′‐dicarbox­aldehyde, C₁₆H₁₅­NO₂, show similar 1,6‐interactions [N?C=O 2.929 (3) to 3.029 (3) Å] between the di­methyl­amino and aldehyde groups located in the ortho positions of the two rings, which lie at 58.1 (1)–62.4 (1)° to each other.     

[1,3‐Bis(4‐nitrophenyl)triazenido](triphenylphosphine)gold(I)

In the title complex, [Au(C₁₂H₈N₅O₄)(C₁₈H₁₅P)], the coordination geometry about the Au^I ion is linear, with one deprotonated 1,3‐bis(4‐nitro­phenyl)­triazenide ion, [O₂NC₆H₄N=N–NC₆H₄NO₂]⁻, acting as a monodentate ligand (two‐electron donor), and one neutral tri­phenyl­phosphine mol­ecule completing the metal coordination. The triazenide ligand is almost planar (r.m.s. deviation = 0.0767 Å), with the largest interplanar angle being 11.6 (7)° between the phenyl ring of one of the terminal 4‐nitro­phenyl substituents and the plane defined by the N=N—N triad. The Au—N and Au—P distances are 2.108 (5) and 2.2524 (13) Å, respectively. Pairs of mol­ecules generated by centrosymmetry are associated into a supramolecular array via intermolecular C—H⋯O inter­actions, and N⋯C and N⋯O π–π interactions.     

Crystal structure of a liquid crystal non‐symmetric dimer: cholesteryl 4‐[4‐(4‐n‐butylphenylethynyl)phenoxy]butanoate

The crystal structure of cholesteryl 4‐[4‐(4‐n‐butylphenylethynyl)phenoxy]butanoate [phase sequence: Cr 155°C (46.1?J?g^?1) SmA 186.8°C (1.5?J?g^?1) TGB‐N* 204.7 (6?J?g^?1) I] has been solved from single crystal X‐ray diffraction data. The compound crystallizes in the monoclinic space group P2₁ with unit cell parameters: a?=?13.129(2), b?=?9.3904(10), c?=?17.4121(8)?Å, β?=?92.790(7)°, Z?=?2. The structure has been solved by direct methods and refined to R?=?0.0606 for 3?250 observed reflections. The bond distances and angles are in good agreement with the corresponding values for compounds containing phenyl and cholesterol moieties. The phenyl rings A and B are planar. The dihedral angle between the least‐squares planes of the two phenyl rings is 28°. The cholesterol moiety has the usual structure: the C and E rings have chair conformations, and the D and F rings adopt half‐chair conformations. The molecules in the unit cell are arranged in an antiparallel manner. The crystal structure is stabilized by an intermolecular C–H…O contact of 2.989(10)?Å.     

A ruthenium complex with 1,5‐di­phenyl‐3‐thio­carbazone (dithizone) as monodentate ligands: bis(2,2′‐bipyridyl‐κ2N,N′)­bis­(dithizonato‐κS)ruthenium(II)

The title compound, [Ru(C₁₃H₁₁N₄S)₂(C₁₅H₈N₂)₂], has C₂ symmetry, with bidentate 2,2′‐bipyridyl ligands dictating a cis geometry around the Ru^II center. The monodentate S‐bonded dithizone ligands are almost planar, except for one of the phenyl rings, which is twisted by 34.2 (4)° from the N/N/C(S)/N/N plane. The Ru—S bond length is 2.4140 (13) Å, and the Ru—N bond lengths are 2.048 (4) and 2.074 (4) Å.     

Propynylferrocene and (phenyl­ethyn­yl)­ferrocene

The title compounds, propynylferrocene, [Fe(C₅H₅)(C₈H₇)], (I), and (phenyl­ethyn­yl)ferrocene, [Fe(C₅H₅)(C₁₃H₉)], (II), are stabilized by weak C—H⋯π inter­actions. The C[triple‐bond]C bond distances in these mol­ecules are in the range 1.182 (3)–1.192 (3) Å. In (II), the ferrocenyl and phenyl groups are perpendicular, making an angle of 89.06 (13)°, which is a rare occurrence.     

cis‐Bis­[1,3‐bis(2‐fluoro­phenyl)­triazenido‐κ2N1,N3]­bis­(pyridine‐κN)cadmium(II)

In the title compound, [Cd(C₁₂H₈F₂N₃)₂(C₅H₅N)₂], the Cd atom lies on a crystallographic twofold axis in space group Iba2. The coordination geometry about the Cd^II ion corresponds to a rhombically distorted octahedron, with two deprotonated 1,3‐bis(2‐fluoro­phenyl)­triazenide ions, viz. FC₆H₄NNNC₆H₄F⁻, acting as bidentate ligands (four‐electron donors). Two neutral pyridine (py) mol­ecules complete the coordination sphere in positions cis with respect to one another. The triazenide ligand is not planar (r.m.s. deviation = 0.204 Å), the dihedral angle between the phenyl rings of the terminal 2‐fluoro­phenyl substituents being 24.6 (1)°. The triazenide and pyridine Cd—N distances are 2.3757 (18)/2.3800 (19) and 2.3461 (19) Å, respectively. Intermolecular C—H⋯F interactions generate sheets of mol­ecules in the (010) plane.     

3,3′‐Dinitro‐2,2′‐dithiodipyridine

In the title compound, C₁₀H₆N₄O₄S₂, (I), the molecule has a centre of inversion. The structure is a positional isomer of 5,5′‐dinitro‐2,2′‐dithiodipyridine [Brito, Mundaca, Cárdenas, López‐Rodríguez & Vargas (2007). Acta Cryst. E 63 , o3351–o3352], (II). The 3‐nitropyridine fragment of (I) shows excellent agreement with the bonding geometries of (II). The most obvious differences between them are in the S—S bond length [2.1167 (12) Å in (I) and 2.0719 (11) Å in (II)], and in the C—C_ipso—N_ring [119.8 (2)° in (I) and 123.9 (3)° in (II)] and S—C—C [122.62 (18)° in (I) and 116.0 (2)° in (II)] angles. The crystal structure of (I) has an intramolecular C—H...O interaction, with an H...O distance of 2.40 (3) Å, whereas this kind of interaction is not evident in (II). The molecules of (I) are linked into centrosymmetric R⁴₄(30) motifs by a C—H...O interaction. There are no aromatic π–π stacking and no C—H...π(arene) interactions. Compound (I) can be used as a nucleophilic tecton in self‐assembly reactions with metal centres of varying lability.