Synthesis,crystal, and molecular structure of coordination polymers constructed by self-assembly of NiN<Subscript>4</Subscript> cores with 2,2′-iminodibenzoate and nitroprusside ions

Two coordination compounds of compositions [Ni(L¹)(idba)(H₂O)]·1.5 H₂O (1) and [Ni(L²)Fe(CN)₅NO]·C₂H₅OH (2) where L¹ is N, N′-bis(3-aminopropyl)ethylenediamine, L² is 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),2,11,13,15-pentaene, and idba^2? is 2,2′-iminodibenzoate have been synthesized and characterized by elemental analysis, IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic space group P2₁/n (No. 14) with a=9.810(2) Å, b=10.230(2) Å, c=25.350(5) Å, V=2543.6(9) Å³, Z=4, and R=0.0727. The nickel atom is six-coordinated by four N atoms of amine and two O atoms of water and idba^2?. The molecular packing of the complex comprises of an infinite one-dimensional layered network in which the molecules in the crystal are held together by a system of hydrogen bonding. Complex 2, however, crystallizes in the space group C2/c (No. 15) of the monoclinic system with a=19.7990(4) Å, b=14.9440(3) Å, c=19.8800(3) Å, V=5115.90(17) Å³, Z=4, and R=0.0540. The Ni ion in compound 2 has a slightly distorted octahedral arrangement of the N₄ donor atoms of primary ligand L² and two N-donor atoms of the secondary nitroprusside ligand. The structure of 2 displays an extended one-dimensional network formed by linear [—Ni—NC—Fe—CN—] units. A cyclic voltammetric study shows that compound 1 undergoes a quasireversible oxidation attributable to Ni²⁺ → Ni³⁺ in the range 300–420 mV vs SCE.     

Two New One-Dimensional Chain-Like Compounds Constructed from the Sandwich-Type Polyoxotungstate Clusters

Two new one-dimensional chain-like compounds, K₄Na₄[Mn₂(H₂O)₈Mn₄(H₂O)₂(GeW₉O₃₄)₂] · 20.5H₂O (1) and K₂Na₄Cu₂(H₂O)₁₂[Cu(H₂O)₂Cu₄(H₂O)₂(SiW₉O₃₄)₂] · 15H₂O (2), constructed from the sandwich-type clusters, have been obtained by the routine synthetic reactions in aqueous solutions, and their structures were determined by X-ray single crystal diffraction analysis. The crystal data is following: for 1, space group, monoclinic, P _21/n, a = 16.693(3) Å, b = 14.935(3) Å, c = 20.090(4) Å, β = 92.23(3)°, V = 5004.7(17) ų, Z = 2; For 2, space group, triclinic, P _?1, a = 11.744(2) Å, b = 13.415(3) Å, c = 17.609(4) Å, α = 73.08(3)°, β = 82.68(3)°, γ = 65.18(3)°, V = 2409.1(8) ų, Z = 1. The crystal structure of 1 shows a 1D ladder-like chain, built up of the sandwich anions [Mn₄(H₂O)₂(GeW₉O₃₄)₂]^12? and the Mn²⁺ ions. Compound 2 is a polymeric chain, composed of the Cu-substituted sandwich-type anions [Cu₄(H₂O)₂(SiW₉O₃₄)₂]^12? linked by the Cu(H₂O)₄ clusters. These extended materials based on the sandwich-type polyoxoanions are rarely reported in the POM chemistry.     

Crystal structure and properties of [M(NH<Subscript>3</Subscript>)<Subscript>5</Subscript>Cl](NO<Subscript>3</Subscript>)<Subscript>2</Subscript>, (M = Ir,Rh, Ru)

The crystal structures of compounds from the series [M(NH₃)₅Cl](NO₃)₂, (M = Ir, Rh, Ru) were described. The compounds crystallized in the tetragonal crystal system, space group I4, Z = 2. Crystal data for [Ir(NH₃)₅Cl](NO₃)₂ (I): a = 7.6061(1) Å, b = 7.6061(1) Å, c = 10.4039(2) Å, V = 601.894(16) ų, ρ_calc = 2.410 g/cm³, R = 0.0087; [Rh(NH₃)₅Cl](NO₃)₂ (II): a = 7.5858(5) Å, b = 7.5858(5) Å, c = 10.41357(7) Å, V = 599.24(7) ų, ρ_calc = 1.926 g/cm³, R = 0.0255; [Ru(NH₃)₅Cl](NO₃)₂ (III): a = 7.5811(6) Å, b = 7.5811(6) Å, c = 10.5352(14) Å, V = 605.49(11) ų, ρ_calc = 1.896 g/cm³, R = 0.0266. The compounds were defined by IR spectroscopy and XRPA and thermal analyses.     

<Emphasis Type="Italic">cis</Emphasis>-Dioxomolybdenum(VI) complexes of sterically encumbered phenol-based tetradentate N<Subscript>2</Subscript>O<Subscript>2</Subscript> ligands: Structural,spectroscopic, and electrochemical studies

Two cis-dioxomolybdenum(VI) complexes [MoO₂L] (L: L ¹, 2 and L: L ², 3) in a phenol-based sterically encumbered N₂O₂ ligand environment have been synthesized, and their crystallographic characterizations are reported. The orange crystals of 2 are monoclinic, space group P2₁/a with unit cell dimensions as a=16.2407(17) Å, b=7.2857(8) Å, c=18.400(2) Å, β=98.002(9)°, Z=4, and d _cal=1.486 g cm^?3. The light orange crystals of 3, however, are orthorhombic, space group, Pbcn, with unit cell dimensions a=8.3110(12) Å, b=12.637(3) Å, c=34.673(5) Å, Z=4, and d _cal=1.187 g cm^?3. The structures were refined by a full-matrix least-squares procedure on F ² to a final R=0.046 (0.055 for 3) using 4944 (3677) all independent data. In both the cases, the Mo atom exists in a distorted octahedral geometry defined by a N₂O₄ donor set, which features a cis-Mo(–O)₂ and a trans-Mo(OPh)₂ arrangement. Compound 2 undergoes a quasireversible one-electron reduction at ?1.3 V vs Ag/AgCl reference due to Mo^VIO₂/Mo^VO₂ electron transfer and thus providing a rare example of steric solution to the comproportionation–dimerization problem encountered frequently in the development of valid biomimetic models for the active sites of oxomolybdenum enzymes.     

Tetrakis [<Emphasis Type="Italic">N</Emphasis>-(2-pyridyl) sulfonamide] di palladium: synthesize,X-ray diffraction,antibacterial properties and as a novel binuclear Pd-complex for coupling reactions

The N-(2-pyridyl) 4-toluene sulfonamide as a free ligand (PTS) was prepared from the reaction of 2-amino pyridine and 4-toluenesulfonyl chloride in the presence of potassium hydroxide solution 1 M as a base and THF was used as a solvent. The complex tetrakis [N-(2-pyridyl) sulfonamide] di palladium (1) (Pd₂L₄) was also prepared from the reaction of PdCl₂(CH₃CN)₂ using (PTS) in the presence of NaOH 0.5 M and its application in Heck and Suzuki reactions. This complex consists of a binuclear unit consisting of four ligands linked to two palladium atoms via the nitrogen of pyridines ring and the nitrogen of sulfonamides. These compounds were confirmed by FT-IR and ¹H NMR spectroscopy. Moreover, the structure of the complex was studied by single-crystal X-ray diffraction method. The green crystal of Pd₂L₄ [L = N-(2-pyridyl) sulfonamide](1) was found to crystallize in the monoclinic space group C2/c with a = 18.2013(19), b = 19.7544(16), c = 17.2898(19) Å, β = 120.179(8) °; V = 5374.0(9) ų; Z = 4; the final R ₁ = 0.0894, wR ₂ = 0.1754 (or 5867 observed reflections and 318 variables). The Pd–Pd distance is 2.567(2) Å. In addition, PTS and Pd₂L₄ presented different antibacterial behaviors. The free ligand was active against Staphylococcus aureus and Escherichia coli, but the complex was inactive against them.     

A New Sandwich Polyoxometalate Constructed from a Zn<Stack><Subscript>6</Subscript><Superscript>12+</Superscript></Stack> Hexagon Cluster Sandwiched by Two B-α-[BiW<Subscript>9</Subscript>O<Subscript>33</Subscript>]<Superscript>9−</Superscript>

A new sandwich polyoxometalate Na₄Zn₂[Zn₂(H₂O)₁₀(ZnCl)₆(B-α- BiW₉O₃₃)₂] · 40.5H₂O (1) has been obtained in aqueous solution and characterized by IR, UV, element analysis, TG and single-crystal X-ray analysis. Polyoxoanion 1 is composed of a Zn ₆ ¹²⁺ hexagon sandwiched by two [BiW₉O₃₃]^9? units, which is firstly observed in tungstobismutate. The crystal data for compound 1: Triclinic, space group P–1, a = 15.426(3) Å, b = 15.467(3) Å, c = 15.526(3) Å, α = 74.24(3)°, β = 64.37(3)°, γ = 60.73(3)°, V = 2905.3(1) ų, Z = 1.     

Tetramminenickel hydrogen hexamolybdometalates(III)

Tetramminenickel hydrogen hexamolybdoaluminate and hexamolybdogallate(III) of compositions [Ni(NH₃)₄] · H[AlMo₆O₁₈(OH)₆] · 10H₂O (I) and [Ni(NH₃)₄] · H[GaMo₆O₁₈(OH)₆] · 10H₂O (II) were synthesized and characterized by mass spectrometry, thermogravimetry, X-ray powder diffraction, and IR spectroscopy. Their crystals are triclinic. For compound I, a= 17.30 Å, b= 14.69 Å, c= 10.45 Å, α = 129.07, β = 65.91°, γ = 138.01°, V = 1338.7l ų, ρ_calcd = 2.75g/cm³, Z = 2; for compound II, a = 17.38 Å, b= 14.75 Å, c= 10.51 Å, α = 131.38°, β= 65.96°, γ = 138.09, V = 1338.15 ų, ρ_calcd = 2.68 g/cm³, Z = 2.     

A novel synthesis of 2,5-diphenylpyrazine

The compound C₁₆H₁₂N₂ (2,5-diphenylpyrazine) was obtained as the by-product of synthesizing 5H-Imidazol[2,3-b]isoquinoline-1-ethanol-5-one,1,2,3,10b-tetrahydro-, β(S)-phenyl-3(S)-phenyl-(compound 2), and its structure was determined by X-ray diffraction. The crystal is monoclinic, P2(1)/c, a = 13.466(5) Å, α = 90.00º, b = 5.758(2) Å, β = 93.049(9)º, c = 7.713(3) Å, γ = 90.00º, V = 597.2(4) Å³, Z = 2, Dcalc. = 1.292 mg/m³; the final R factor is R₁ = 0.0592, 771 for reflections with I ₀ > 2σ(I ₀).     

Synthesis,crystal structure,and vibrational spectrum of lithium <Emphasis Type="Italic">N</Emphasis>-(4′-benzo-15-crown-5)-5-bromo-2-hydroxyphenylaldiminatozinc perchlorate dihydrate

The synthesis, the IR absorption spectrum, and X-ray diffraction analysis of the complex [ZnLi(L¹)₂(H₂O)](ClO₄) · H₂O (I) (HL¹ = N-(4′-benzo-15-crown-5)-5-bromo-2-hydroxyphenylaldimine) are described. The crystals of I are monoclinic, a = 19.840(4) Å, b = 13.947(3) Å, c = 19.956(4) Å, β = 117.06(3)°, V = 4917.4(17) ų, Z = 4, space group P2₁/n, R = 0.0609 for 1409 reflections with I > 2σ(I). In the complex cation [ZnLi(L¹)₂(H₂O)]⁺, the Zn atom is bound to a distorted tetrahedral array of two N atoms (av. Zn-N, 2.027(10) Å) and two O atoms (av. Zn-O, 1.8968(8) Å) of two deprotonated L¹ ligands. The Li atom linked to the five ether oxygen atoms (av. Li-O_ether, 2.254(3) Å) sits atop the benzo-15-crown-5 (B15C5) macrocyclic plane of one coordinated L¹ ligand. The Li coordination is completed by water oxygen (Li-O(w1), 1.83(5) Å). The B15C5 cavity of the second coordinated ligand L¹ is vacant.     

Synthesis and characterization of ruthenium heterocyclic-thiocarboxylate complexes

The cyclopentadienyl ruthenium complexes CpRuL₂SCO-het (Cp = η⁵-C₅H₅; L₂ = 2PPh₃ (1), dppe (2)) bearing heterocyclic thiocarboxylate ligands have been synthesized from the reaction of CpRuL₂SH with heterocyclic acid chlorides (ClCO-2-C₄H₃S (a); ClCO-2-C₄H₃O (b); ClCO-1-C₄H₈N (c)). Bubbling of CO gas through a THF solution of (1) produced the mixed carbonyl–phosphine complexes CpRu(PPh₃)(CO)SCO-het (3) with high yields. Complexes (1)-(3) were characterized by spectroscopic methods (i.r., ¹H-n.m.r., ³¹P-n.m.r.) and elemental analysis. The molecular structure of CpRu(PPh₃)₂SCO-2-C₄H₃S (1a) verifies that the thiocarboxylate ligands bind via the sulfur atom (Ru–S = 2.406(2) Å).     

Synthesis,Crystal Structure and Catalytic Property of a New Cadmium Coordination Polymer

A new cadmium coordination polymer [Cd(L)(Cl)(H₂O)]_n (1) (L = 5-(imidazol-1-yl)-2-pyridine carboxylic anion) constructed from dinuclear cadmium clusters has been synthesized under hydrothermal condition and structurally characterized by single-crystal X-ray diffraction analysis. The compound crystallizes in triclinic system, space group P-1, with a = 6.8747(6), b = 9.7434(8), c = 9.9119(7) Å, α = 118.615(8)°, β = 104.445(7)°, γ = 94.815(7)°, V = 548.01(9) ų, Z = 2. Compound 1 is a one-dimensional (1D) double chain structure based on dinuclear [Cd₂(Cl)₂] clusters, and is further extended to a 3D supramolecular framework by hydrogen bonds. As a Lewis acid catalyst, compound 1 exhibits excellent catalytic performance for the acetalization reaction under mild conditions and can be reused several times without a significant decrease of the catalytic activity.     

Synthesis,crystal structure of new linear trinuclear isovalence Co(II)([Co<Subscript>3</Subscript>(H–L)<Subscript>2</Subscript>(L)<Subscript>2</Subscript>]), and visualizing intermolecular interactions with Hirshfeld surface method

S-allyl-β-N-[(2-hydroxyphenyl)methylene]hyrazinecarbodithioate) (1, H₂L), the Schiff base of dithiocarbazate with unsaturated allyl substitution, can act as a new tridentate SNO ligand H₂–L and react with cobalt(II) nitrate hexahydrate to form the novel linear trinuclear isovalence Co(II) complex, [Co₃(H–L)₂(L)₂] 2C₂H₅OH (2). The compounds were characterized by elemental analysis, infrared, and ultraviolet spectroscopy. Compound 2 was also characterized by single-crystal X-ray analysis and crystallizes in the orthorhombic space group, Pbcn, with a = 30.643(1) Å, b = 9.118(4) Å, c = 19.017(7) Å, α = β = γ = 90°, V = 5312.95 Å³, Z = 4, and R ₁ = 0.0790, (wR ₂) = 0.1223. The six-coordinate central Co(II) atom is bonded to two deprotonated metal-containing ligands. The terminal Co(II) atoms are in a square planar SNON four-coordinate environment and connected to the central Co(II) by N-atoms from the ligand backbone. For quantifying the intermolecular interactions in crystal lattice, the new d _norm surface and the breakdown of fingerprint plots have been used for visualizing and exploring the compound 2.     

Substituent group effects on the self-assembly of oxovanadium(V) complexes with hydrazone ligands bearing benzoic acid (1-methyl-3-oxobutylidene)hydrazide backbones

An oxo-bridged dinuclear oxovanadium(V) complex, [V₂O₂(μ-O)(L¹)₂] (1) [H₂L¹ = 3-nitrobenzoic acid (1-methyl-3-oxobutylidene)hydrazide], and a mononuclear oxovanadium(V) complex, [VO(OMe)(L²)] (2) [H₂L² = 3-hydroxynaphthalene-2-carboxylic acid (1-methyl-3-oxobutylidene)hydrazide], were prepared by the reactions of [VO(acac)₂] with H₂L¹ and H₂L², respectively, in methanol. Both complexes were characterized by elemental analysis, IR spectra, and single crystal X-ray crystallography. The crystal of 1 crystallizes in the monoclinic space group P2/n, with a = 13.116(3) Å, b = 7.597(2) Å, c = 13.927(2) Å, β = 104.851(2)°, V = 1341.4(5) ų, Z = 2. The crystal of 2 crystallizes in the triclinic space group \(P\overline 1 \), with a = 7.897(2) Å, b = 9.690(2) Å, c = 11.576(3) Å, α = 86.405(2)°, β = 70.597(2)°, γ = 85.991(2)°, V = = 832.7(3) ų, Z = 2. The V atoms in the complexes have square pyramidal environment. The substituent groups attached to the aromatic rings can influence the self-assembly of the complexes.     

Synthesis and Structure of a New Cu(II) Complex with 2-Benzoylpyridine and Its Hydrolyzed Derivative H<Subscript>2</Subscript>bpd as Ligands

A new Cu(II) complex, [Cu₂(bzpy)₂(Hbpd)₂(H₂O)](ClO₄)₂·H₂O (1) based on bzpy (bzpy = 2-benzoylpyridine) and H₂bpd (benzyl-2-pyridylmethanediol) mixing ligands, was synthesized and characterized by IR, UV–Vis spectra, TGA and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P2(1)/n with a = 18.7790(2), b = 14.4609(3), c = 18.9434(4) Å, β = 102.17°, V = 5028.63(16) ų, Z = 4. The complex bears a dinuclear structure in which two Cu(II) atoms adopt elongated square pyramidal (SP) and octahedral geometry, respectively, and two intramolecular π…π interactions are also observed. Then with the help of intermolecular π…π and CH…π interactions, a 1D chain structure is formed based on the dinuclear unit. Thermal stability of 1 was studied.     

Heterobimetallic compounds [Ru(η<Superscript>5</Superscript>-Cp)(dppf)X] (X = Cl,Br, I and N<Subscript>3</Subscript>): synthesis,electrochemical analysis,and the crystal structure of [Ru(η<Superscript>5</Superscript>-Cp)(dppf)I] [dppf = 1,1′-bis(diphenylphosphino)ferrocene]

A series of new ruthenium-iron based derivatives [Ru(η⁵-Cp)(dppf)Cl] (1), [Ru(η⁵-Cp)(dppf)Br] (2), [Ru(η⁵-Cp)(dppf)I] (3) and [Ru(η⁵-Cp)(dppf)N₃] (4) were obtained by reactions of [Ru(η⁵-Cp)(PPh₃)₂Cl] with 1,1′-bis(diphenylphosphino) ferrocene (dppf) and characterized by IR, NMR (¹H, ¹³C and ³¹P), ⁵⁷Fe Mössbauer spectroscopy and cyclic voltammetry. Additionally, the compound (3) was structurally characterized by X-ray crystallography, and the results were as follows: orthorhombic, Pbca, a = 18.2458(10), b = 20.9192(11), c = 34.4138(19) Å, α = β = γ = 90°, V = 13135.3(12) Å³ and Z = 16.     

New organic–inorganic hybrid structure based on paradodecatungstate clusters and imidazolium cations

An organic–inorganic hybrid material based on paradodecatungstate anions and imidazolium cations, Na₂(HIm)₈(H₂W₁₂O₄₂)·10H₂O (HIm: imidazolium), has been synthesized under mildly acidic conditions. This compound was characterized by single-crystal X-ray diffraction, IR and UV–visible spectroscopies, and thermogravimetric and differential thermal analyses. The compound crystallizes in the triclinic P-1 space group with a = 11.6945(8) Å, b = 12.4782(6) Å, c = 14.0952(9) Å, α = 106.041(3)°, β = 109.338(2)°, γ = 100.249(3)°, V = 1781.0(3) Å³, and Z = 2. The crystal structure exhibits an infinite 1D inorganic structure built from [H₂W₁₂O₄₂]^10? clusters and sodium cations; adjacent chains are further joined up by hydrogen-bonding interactions between protonated imidazole cations, water molecules, and polyoxoanions, to form a 3D supramolecular architecture.     

Syntheses,characterization, and crystal structures of two dinuclear nickel(II) and copper(II) complexes with Schiff bases

The phenolic azide bridged dinuclear nickel(II) complex, [Ni₂(L¹)₂(N₃)(H₂O)(μ_1,1-N₃)] · EtOH (I), and the thiocyanate bridged dinuclear copper(II) complex, [Cu₂(L²)₂(μ_1,1-NCS)₂] (II), where L¹ and L² are the deprotonated forms of 2-mothoxy-6-[(2-piperidin-1-ylethylimino)methyl]phenol and 2,4-dichloro-6-[(2-methylaminoethylimino)methyl]phenol, respectively, were synthesized and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. The crystal of I is orthorhombic: space group Pbca, a = 12.172(1), b = 20.953(1), c = 29.779(2) Å, V = 7594.8(9) ų, Z = 8. The crystal of II is monoclinic: space group P2₁/n, a = 8.7615(11), b = 19.672(2), c = 16.568(2) Å, β = 99.449(2)°, V = 2816.9(6) ų, Z = 4. The Ni atoms in I are in octahedral coordinations, and the Cu atoms in II are in square-pyramidal coordinations.     

Self-Assembly,Crystal Structure and Analysis of Intermolecular Interactions of the Supramolecular Compound Based on Hexamolybdochromate(III), Sulfate and Piperazine

A new supramolecular compound based on Anderson-B hexamolybdochromate, (H₂Pz)₃[Cr(OH)₆Mo₆O₁₈H](SO₄)₂·12H₂O (1) (Pz = piperazine) was synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction (Mo Kα). The compound crystallizes in monoclinic system, P21/c space group with a = 13.5708(6) Å, b = 17.3711(8) Å, c = 22.2387(9) Å, β = 110.631(2)°; V = 4906.3(4) Å³, Z = 4, D _c  = 2.290 g/cm³, F(000) = 3364.0; μ = 1.905, S = 1.033. The final R = 0.0398 and wR = 0.0971. The H₂pz²⁺ ions and sulfate anions in 1 are arranged through hydrogen bonds into a hexagonal network in [202] plane and hexamolybdochromates anions (CrMo₆) fill in the hexagonal vacancies. The networks stack in such a way that each anion links two sulfate ions from adjacent networks via hydrogen bonds with short (CrMo₆)O···OSO₃ distances of 2.637–2.697 Å. A lot of hydrogen bonds are formed between water molecules, sulfate, H₂pz²⁺ ions and CrMo₆ anions, which are the dominating force constructing the supramolecular structure. Hirshfeld surface analysis of 1 gives us the details of intermolecular interactions in the crystals of 1 in a visual manner and shows that the CrMo₆ anion acts as a stronger hydrogen bond donor than as an acceptor.     

A Novel 3D Platinum–Thallium Coordination Polymer having Strong Metal–Metal Interactions

A new three-dimensional platinum(II)–thallium(I) coordination polymer [{Pt(pda)(NHCOtBu)₂}₄Tl₄][Pt(CN)₄]₂·2H ₂ O (pda = 1,2-propyldiamine) has been prepared from the direct reaction of [Tl₂Pt(CN)₄] and [Pt(pda)(NHCOtBu)₂] in water, and its structure was characterized by X-ray diffraction analysis. The compound crystallizes in monoclinic, space group Pn, a = 11.567(2) Å, b = 11.570(2) Å, c = 37.677(8)Å, β = 94.64(3)°, V = 5025.8(17) Å³, Z = 2, R1 = 0.0679 and wR2 = 0.1574 [I >  2σ (I)], Goodness-of-fit on F ² = 1.055. The compound exhibits a novel 3D network structure consisting of [Pt(CN)₄]^2? connected 1D infinite Pt–Tl–Pt–Tl chains via strong Pt–Tl bonds.     

Molecular structure and conformation of nitrobenzene reinvestigated by combined analysis of gas-phase electron diffraction,rotational constants,and theoretical calculations

The molecular structure and conformation of nitrobenzene has been reinvestigated by gas-phase electron diffraction (GED), combined analysis of GED and microwave (MW) spectroscopic data, and quantum chemical calculations. The equilibrium r _e structure of nitrobenzene was determined by a joint analysis of the GED data and rotational constants taken from the literature. The necessary anharmonic vibrational corrections to the internuclear distances (r _e ? r _a) and to rotational constants (B _e ⁽ⁱ⁾  ? B ₀ ⁽ⁱ⁾ ) were calculated from the B3LYP/cc-pVTZ quadratic and cubic force fields. A combined analysis of GED and MW data led to following structural parameters (r _e) of planar nitrobenzene (the total estimated uncertainties are in parentheses): r(C–C)_av = 1.391(3) Å, r(C–N) = 1.468(4) Å, r(N–O) = 1.223(2) Å, r(C–H)_av = 1.071(3) Å, \({\angle}\)C2–C1–C6 = 123.5(6)°, \({\angle}\)C1–C2–C3 = 117.8(3)°, \({\angle}\)C2–C3–C4 = 120.3(3)°, \({\angle}\)C3–C4–C5 = 120.5(6)°, \({\angle}\)C–C–N = 118.2(3)°, \({\angle}\)C–N–O = 117.9(2)°, \({\angle}\)O–N–O = 124.2(4)°, \({\angle}\)(C–C–H)_av = 120.6(20)°. These structural parameters reproduce the experimental B ₀ ⁽ⁱ⁾ values within 0.05 MHz. The experimental results are in good agreement with the theoretical calculations. The barrier height to internal rotation of nitro group, 4.1±1.0 kcal/mol, was estimated from the GED analysis using a dynamic model. The equilibrium structure was also calculated using the experimental rotational constants for nitrobenzene isotopomers and theoretical rotation–vibration interaction constants.