Anion-directed organized assemblies of protonated pyrazole-based ionic salts

The reactions of 3(5)-(4-methoxyphenyl)-5(3)-phenyl-1H-pyrazole (L ¹ ) with nitric acid and 5-(4-benzyloxyphenyl)-3-(furan-2-yl)-1H-pyrazole(L ² ) with hydrochloric acid produced [HL ¹ · NO₃] (Salt-1) and [HL ² · Cl] (Salt-2). The structures of Salt-1 and Salt-2 were determined by single crystal X-diffraction. In Salt-1, HL ¹ showed [2 + 2] binding of NO₃ ^? ions in the solid state to form dimer architecture with R ₁ ² (4) and R ₄ ⁴ (14) graph sets. An anion directed one-dimensional anion-assisted helical chain with active participation of the chloride ion and protonated pyrazole via N–H···Cl hydrogen bonding in Salt-2. In addition, the protonated HL ² molecules interacted with each other through weak C–H···π interactions resulting in the formation of another one-dimensional helical chain.     

Simplified bicyclic cage-type molecule as a C 3 -symmetric host: X-ray and FTIR characterization of encapsulation of a nitrile molecule

We synthesized a new amine-type host molecule 2 by 2 steps, using 1,3,5-tris(aminomethyl)-2,4,6-trimethylbenzene and 2,6-pyridinedicarboxaldehyde as starting materials. Recrystallization of 2·6H₂O from hot acetonitrile, hot propionitrile and hexane/benzonitrile solutions gave colorless crystals of MeCN@2·MeCN·2H₂O, EtCN@2·EtCN, and 8H₂O@2·PhCN. In the former two crystals, the nitrile compounds were captured inside of the cavity of 2. On the other hand, in the latter one, the benzonitrile was laid outside 2. Infrared spectral measurements of MeCN@2·MeCN·2H₂O, EtCN@2·EtCN, and 8H₂O@2·PhCN showed that absorption bands assignable to the C ≡ N stretching vibrations of nitrile compounds were observed at 2240, 2241, and 2226 cm^?1 for MeCN@2·MeCN·2H₂O, EtCN@2·EtCN, and 8H₂O@2·PhCN, respectively. The former two peaks shifted to a lower energy region by 6–13 and 21–26 cm^?1 than those of liquid and gas phases of MeCN and EtCN, respectively. That for 8H₂O@2·PhCN shifted to a slightly lower region by 2 and 12 cm^?1 those of liquid and gas states of PhCN, respectively, indicating that the outer benzonitrile molecule dose not so much interact with 2 in the crystal.     

Benzoylacetonate and its fluorinated derivatives as ligands for Co(II) complexes: the effect of the presence of fluorine atoms on the crystal packing

The influence of the introduced fluorine atoms to diketonato backbone exerted on the crystal packing was studied on cobalt(II) bis(4,4,4-trifluoro-1-phenylbutane-1,3-dionato-κ ² O,O′) compounds with pyridine (1), 2,2′-bipyridine (2) and 1,10-phenanthroline (4), and cobalt(II) bis(benzoylacetonato-κ ² O,O′) compound with 2,2′-bipyridine (3). The solid-state structures of 1–4 were determined by single crystal X-ray analysis. The coordination of Co(II) is octahedral in all four compounds. The differences in crystal packing of 1 with regard to the known complexes with non-fluorinated analogue and 4,4,4-trifluoro-1-(4-fluorophenyl)butane-1,3-dionate were observed. Unit cell parameters of 2·½C₇H₈ and 3·½C₇H₈ slightly differ, but they have similar crystal packing dominated by the π–π interactions. Strong π–π interactions and weak C–H···π(arene) and C–F···π(arene) interactions are present in 2–4, while no significant intermolecular interactions are present in 1.     

Two new 2D copper(II) complexes constructed from a flexible bis-pyridyl-bis-amide ligand and two aromatic tricarboxylates: syntheses, crystal structures, fluorescence, and electrochemical properties

Two new 2D metal-organic complexes, namely [Cu(3-dpyb)(1,2,4-HBTC)(H₂O)]·H₂O (1) and [Cu₃(3-dpyb)₃(SIP)₂(H₂O)₈]·6H₂O (2) [3-dpyb?=?N,N??-bis(3-pyridinecarboxamide)-1,4-butane, 1,2,4-H₃BTC?=?1,2,4-benzenetricarboxylic acid, H₃SIP?=?5-sulfoisophthalic acid], have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction analyses. Single crystal X-ray analyses reveal that the two Cu(II) complexes show different 2D coordination networks, the 4-connected (4⁴·6²) topology for complex 1 and the (4·6²)₂(4²·6²·8²) topology for complex 2. In the 2D layers of complexes 1 and 2, the 3-dpyb ligands adopt a typical ?? ₂-bridging mode (via ligation of two pyridyl nitrogen atoms), while 1,2,4-HBTC and SIP serve as a linear spacer and a ??V??-like linker, respectively, to connect the adjacent Cu(II) centers. The adjacent 2D layers are extended to 3D supramolecular networks via hydrogen-bonding interactions. The fluorescence properties of both complexes and electrochemical properties of complex 2 have also been investigated. The complex 2 bulk-modified carbon paste electrode (2-CPE) displayed a one-electron redox wave in potential range of 600?C200?mV in 1?M H₂SO₄ aqueous solution, and 2-CPE showed good electrocatalytic activity toward the reduction of nitrite.     

Synthesis, crystal structures and electrochemical properties of CoIII complexes with hexadentate ligand containing thioether-amidopyridyl donor set

Two new cobalt(III) complexes of the hexadentate ligand [1,4-bis[o-(pyridine-2-carboxamidophenyl)]-1,4-dithiobutane] (H₂bpctb) with N₄S₂ donor set atoms have been synthesized. A reaction of Co(CH₃COO)₂·4H₂O with (H₂bpctb) leads to the formation of [Co^III(bpctb)]PF₆ (1) having a CoN₂(pyridine)N′₂(amide)S₂(thioether) coordination by symmetric bpctb^2? ligand. A similar reaction under slightly different conditions, however, gives [Co^III(L ^a )(L ^b )] (2), resulting from a C–S bond cleavage reaction triggered by an acetate ion as a base, having CoN₂(pyridine)N′₂(amide)S(thioether)S′(thiolate) coordination. These two Co(III) complexes have been characterized by elemental analyses and spectroscopic methods, and the crystal and molecular structures of [Co^III(bpctb)]PF₆ (1) in the form of the solvate (1·MeOH·H₂O) and of [Co^III(L ^a )(L ^b )] (2) have been determined by X-ray crystallography. The Co atoms of both complexes exhibit distorted octahedral geometry. The electrochemical investigation of [Co(bpctb)]PF₆·MeOH·H₂O (1·MeOH·H₂O) and [Co^III(L ^a )(L ^b )] (2) by cyclic voltammetry reveals a reversible Co^III–Co^II redox process at E _1/2 = ?0.32 V (ΔE _p = 80 mV); for 1, and E _1/2 = ?0. 87 V (ΔE _p = 70 mV) for 2.     

Synthesis,identification, crystal structure and theoretical study of a Ce(IV) complex

The compound (dienH₃)₂(pydc)_3, 1; dien: diethyltriamine, pydcH₂: pyridine-2,6-dicarboxylic acid, as a proton transfer ligand was applied to synthesize (dienH₃)₂[Ce(pydc)₃]₃·16.75H₂O, 2. The compounds were examined by elemental analysis, IR, UV and NMR spectroscopy. In addition, the compound 2 was studied by TG analysis, single crystal X-ray diffractometry and computational calculations. Geometry optimizations were carried out using B3PW91 hybrid density functional and quasi-relativistic effective core potentials (ECP46MWB) to represent the atomic core of cerium and 6–311G(d, p) basis set that used to describe the electrons of oxygen, nitrogen, carbon and hydrogen atoms. Also, natural bond orbital (NBO) analysis at the B3 PW91/A level gives the natural electron population and the natural charge for each atom. Cerium atom in 2 is nine-coordinated with three (pydc)^2? groups giving an anionic complex which is balanced by (dienH₃)³⁺ in the crystal structure. Several intermolecular interactions including O–H···O and N–H···O hydrogen bonds, face-to-face and edge-to-face stackings are responsible to stabilize the extended structure.     

Electron ionization induced metastable decompositions of isomeric trimethylsilylmethanol, (CH3)3SiCH2OH, and methoxytrimethylsilane, (CH3)3SiOCH3

The metastable decompositions of trimethylsilylmethanol, (CH₃)₃SiCH₂OH (MW: 104, 1) and methoxytrimethylsilane, (CH₃)₃SiOCH₃ (MW: 104, 2) upon electron ionization have been investigated by use of mass-analyzed ion kinetic energy (MIKE) spectroscopy and D labeling. The metastable ions of 1 ^·+ decompose to give the fragment ions m/z 89 (CH ₃ ^· loss) and 73 (^·CH₂OH loss), whereas those of 2 ^·+ only yield the fragment ion m/z 89 (CH ₃ ^· loss). The latter fragment ion is generated by loss of a methyl radical from the trimethylsilyl group via a simple cleavage reaction as shown by D labeling. However, the fragment ions m/z 89 and 73 from 1 ^·+ are generated following an almost statistical exchange of the original methyl and methylene hydrogen atoms in the molecular ion as shown also by D labeling. This exchange indicates a complex rearrangement of the molecular ion of 1 ^·+ prior to metastable decomposition for which as key step a 1,2-trimethylsilyl group migration from carbon to oxygen is suggested. A different behavior is also found between the source-generated m/z 89 ions from 1 ^·+ which decompose in the metastable time region to give ions m/z 61 by loss of ethylene and those from 2 ^·+ which decompose in the metastable region to yield ions m/z 59 by elimination of formaldehyde.     

Construction of 0D to 3D Copper(II) MOFs based on heterocyclic carboxylic acid: Synthesis,structures, cyclic voltammograms,and luminescent properties

The crystal structures of MOFs [Cu(PDA)(Phen)(H₂O)]₂ · 5H₂O (I) and [Cu(PZCA)₂(H₂O)₂] · 2H₂O (II) (H₂PDA = pyridine-2,6-dicarboxylic acid, Phen = 1,10-phenanthroline, HPZCA = pyrazine-2-carboxylic acid, H₂PZDA = pyrazine-2,3-carboxylic acid) have been prepared under hydrothermal conditions. These MOFs have been characterized by element analysis, single-crystal X-ray diffraction, thermogravimetric analyses and IR spectroscopy. 3D frameworks of MOFs I and II are fabricated from zero-dimensional (0D) motifs through hydrogen bonds and π-π interactions. In MOF II, the PZCA ligand comes from in situ decarboxylation of the part of pyrazine-2,3-dicarboxylic acid (H₂PZDA). Luminescent emissions bands of MOF I in methanol have been measured at room temperature and it displays selectivity to Zn²⁺, Cu²⁺, Pb²⁺, and Cd²⁺ ions. Cyclic voltammetry of MOFs I and II showed that the Cu(II/I) couple is irreversible.     

Guest inclusion in cyclic imides containing flexible tethers

Guest inclusion properties of two cyclic imides which have carboxylic acids connected through flexible tether, namely, 4-(1,3-dioxo-1,3-dihydro-isoindol-2-ylmethyl)-cyclohexanecarboxylic acid (1) and 4-(1,3-dioxo-1H,3H-benzo[de]isoquinolin-2-ylmethyl)-cyclohexanecarboxylic acid (2) are studied. The crystals of host 1 containing one molecule of 1, the crystals of 4,4′-bipyridine (bpy) cocrystal of 1 containing one molecule of 1 and half molecule of bpy (1a), the crystals of 1,4-dioxane solvate of 1 containing two molecule of 1 and one and half molecule of 1,4-dioxane (1b) and the crystals of quinoline solvate of 1 containing one molecule of 1 and one molecule of quinoline (1c) in their crystallographic asymmetric units are investigated. Intermolecular hydrogen bonded two dimensional (2D) sheet structure of 1 and 3D channel network of 1b are comprised of cyclic R ₂ ² (8) hydrogen bond motifs; whereas cleavage of dimeric carboxylic acid R ₂ ² (8) motifs occurs in the structures of 1a and 1c in which 3D host–guest networks are comprised of discrete O–H···N and cyclic R ₂ ² (7) interactions, respectively. Various types of weak interactions between the two symmetry nonequivalent host molecule are found to be responsible for the formation of channels (14 × 11 Å) filled by guest 1,4-dioxane molecules in the crystal lattice of 1b. Two different solvates of 2 containing one molecule of 2 with a water molecule (2a) and one molecule of 2 with a quinoline molecule (2b) in their crystallographic asymmetric units, respectively, are also crystallized in different space groups. The quinoline molecules are held with host molecules by discrete O–H···N and C–H···O interactions and reside inside the voids formed by 3D repeated hexameric assemblies of host molecules in the crystal lattice of 2b.     

Synthesis, spectroscopic, and thermal investigation of transition and non-transition complexes of metformin as potential insulin-mimetic agents

Complexes of [Mn(MF)₂(Cl)₂]·2H₂O (1), [Fe(MF)₂(Cl)₂]Cl·4H₂O (2), [Ni(MF·HCl)₂(Cl)₂]·6H₂O (3), [Cu(MF·HCl)₂(Cl)₂] (4), [Zn(MF·HCl)₂](NO₃)₂·6H₂O (5), [Cd₂(MF·HCl)(Cl)₄(H₂O)] (6), [Mg(MF·HCl)₂(Cl)₂]·6H₂O (7), [Sr₂(MF·HCl)(Cl)₄(H₂O)] (8), [Ba(MF·HCl)₂(Cl)₂]·2H₂O (9), [Pt(MF)₄] (10), [Au(MF)₃]Cl₃ (11), and [Pd(MF)₂]Cl₂ (12) were synthesized from Legitional behavior of metformin drug as a diabetic agent. The authenticity of the transition and non-transition metal complexes were characterized by elemental analyses, molar conductivity, (infrared, UV–Vis) spectra, effective magnetic moment in Bohr magnetons, electron spin resonance, thermal analysis, X-ray powder diffraction as well as scanning electron microscopy. Infrared spectral studies as well as elemental analyses revealed the existence of metformin in the base or hydrochloride salt forms in the chelation state acts as a bidentate ligand while the platinum(IV) complex is coordinated through the deprotonation of –NH group. The magnetic and electronic spectra of Mn(II), Fe(III), Ni(II), and Cu(II) complexes suggest an octahedral geometry. Antimicrobial screening of metformin and its complexes were determined against the (G⁺ and G^?) bacteria (Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa) and fungi (Aspergillus flavus and Candida albicans).     

Synthesis, crystal structures, and properties of inorganic-organic hybrid complexes constructed from copper(II) macrocyclic fragment

Reaction of a macrocyclic copper(II) complex [Cu(L)](ClO₄)₂ · 3H₂O (I) (L = 1,3,10,12,16,19-hexaazatetracyclotetracosane) with a hexapod carboxylate ligand H₆TTHA (H₆TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid) and a tripod carboxylate ligand H₃TATB (H₃TATB = 4,4′,4″-S-triazine-2,4,6-triyl-tribenzoic acid) yielded two mononuclear copper(II) complexes [Cu(L)][H₄TTHA] · 4H₂O (II) and [Cu(L)][HTATB] · 4H₂O (III). The complexes I–III have been structurally characterized. The crystal structures of complexes II and III show the copper(II) ion has a distorted pentacoordinate square-pyramidal geometry with two secondary and two tertiary amines from the macrocyclic complex [Cu(L)]²⁺ and one oxygen atom from the carboxylate ligand group at the axial position. The UV-Vis spectra are utilized to discuss the hydrolysis of the complex II.     

Crystal structure,thermal behavior,and microbiological activity of a thiosemicarbazide-type ligand and its cobalt complexes

The synthesis of a potentially bioactive mixed-valence Co^III/Co^II complex with 2-acetylpyridine S-methylisothiosemicarbazone (HL) ligand is described. The crystal and molecular structure of the formed [Co^IIIL₂][Co^IICl₃ py]·Me₂CO (I) compound (py stands for pyridine) is determined by single-crystal X-ray crystallography. It’s thermal decomposition along with the decomposition of the ligand and six structurally related complexes with formulas [CoL₂]NO₃·MeOH (1), [CoL₂]Br·MeOH (2), [CoL₂]HSO₄·MeOH (3), [CoL₂]₂[Co^II(NCS)₄] (4), [Co(HL)(L)]I₂·2MeOH (5), and [Co(HL)(L)][Co^IICl₄]·MeOH (6) was determined by simultaneous TG/DSC measurements. The decomposition pattern is evaluated using TG/DTA-MS data. The results were related to the solvent/moisture content and the decomposition mechanism of the compounds. The antimicrobial activity of the ligand and of all the complexes was tested in vitro for selected gram-negative and gram-positive bacteria and fungi. The activity of the ligand against all tested bacteria is comparable with those obtained for standard antibiotics, while it is less active against fungi. Surprisingly, the activity of the complexes is very low. The low antimicrobial activity of the complexes may be in connection with their high thermodynamic and kinetic inertness in solution. The results are also supported by the relatively high thermal stability of the complexes.     

Novel coordination polymers with 1,4-di(benzimidazole-1-yl)benzene modulated by an anion: Syntheses, structures and properties

Three novel coordination polymers, {[Co(L)(SO₄)(H₂O)](CH₃OH)}_∞ (1), {[Cd(L)₂(SiF₆)](H₂O)}_∞ (2) and [Zn(L)(NO₃)₂]_∞ (3), synthesized from 1,4-di(benzimidazole-1-yl)benzene (L), have been characterized by infrared spectroscopy, elemental analysis and single crystal X-ray diffraction. Compounds 1–3 exhibit different structures. Complex 1 has a 3-D diamond network containing 1-D Co^II chains connected by SO ₄ ^2? · anions; 2 has a 3-D-Po framework with 1-D porous channels along the c axis; and 3 has a 1-D zig-zag chain structure with a 2-D supramolecular network based on π-π interactions. The magnetic properties of 1 and the solid state fluorescence spectra of 2 and 3 have also been explored.     

Synthetic aspects, crystal structures and antibacterial activities of manganese(III) and cobalt(III) complexes containing a tetradentate Schiff base

Three new Schiff base complexes, namely [Mn(L)Cl] · H₂O (1), [Co(L)Cl]₂ · 2CH₃COCH₃ (2) and [Co(L)NCS]₂ (3), where H₂L = 2,2′-[propane-1,2-diylbis(nitriloeth-1-yl-1-ylidene)]diphenol, have been prepared and characterized. The syntheses of 1 and 2 have been achieved by reacting equimolar amounts of the respective metal chloride and the tetradentate Schiff base ligand (H₂L). While the mononuclear Mn(III) complex 1 was obtained with MnCl₂ in acetone medium, the same synthetic system yielded the binuclear Co(III) complex 2 in the presence of CoCl₂. Dissolution of 1 and 2 followed by crystallization with ammonium thiocyanate in methanol yielded two isostructural phenoxo-bridged binuclear complexes, namely [Mn(L)NCS]₂ (previously reported by us) and a new complex [Co(L)NCS]₂ (3), respectively. All the complexes 1–3 have been characterized by microanalytical, spectroscopic, single crystal X-ray diffraction and other physicochemical studies. Structural studies reveal that 1 adopts a distorted tetragonal pyramidal geometry while 2 and 3 comprise dimeric Co(III) units with bridging phenolate oxygen atoms. All the complex units in 1–3 and the respective solvent molecules are held together by weak intermolecular H-bonding to constitute a supramolecular network in the solid state. The antibacterial activity of the complexes has been tested against some Gram(+) and Gram(?) bacteria.     

Synthesis, characterization and catalytic activity of three palladium(II) complexes containing Schiff base ligands

Three new Pd(II) complexes of Schiff base ligands, namely, [Pd₄(L¹)₄] (1), [Pd₂(L²)₂Cl₂] (2) and [Pd(L³)₂Cl₂] (3) [HL ¹ ?=?N-(benzylidene)-2-aminophenol; L ² ?=?N-(2,4-dichlorobenzylidene)-2,6-diethylbenzenamine, L ³ ?=?4-(2,4-dichlorobenzylide-neamino)phenol] have been synthesized using solvothermal methods and characterized by elemental analysis, spectroscopy and single crystal X-ray diffraction. The crystal structures of the free ligands were also determined. The ??-oxygen-bridged tetranuclear cyclometallated Pd(II) complex (1) contains four nearly planar units, in which Pd^II is four-coordinate. Complex 2 is a ??-chloro-bridged dinuclear cyclometallated Pd(II) complex, whereas complex 3 is mononuclear. The Heck reactions of bromobenzene with acrylic acid catalyzed by complexes 1?C3 have also been studied.     

Long, multicenter bonding in π-[terthiophene] 2 2+ dimers

The repulsive nature of the interaction between the cation radicals of the π-[terthiophene] ₂ ²⁺ dimers, 1 ₂ ²⁺ , found in crystals has been concluded from B3LYP/6-31+G(d) calculations. Hence, the bonding component is weaker than the Coulombic repulsion, consistent to recent findings for [TTF]^·+–[TTF]^·+ interactions (TTF = tetrathiafulvalene). The existence of 1 ₂ ²⁺ dimers originates from the cation⁺–anion^? electrostatic interactions, which exceeds the combined effect of the 1 ^.+–1 ^.+ plus (SbF₆)^?–(SbF₆)^? repulsions in 1 ₂(SbF₆)₂, similar to what is found for [TTF]^·+–[TTF]^·+ interactions in [TTF]₂(ClO₄)₂ aggregates and in crystals. The long, multicenter bond in 1 ₂ ²⁺ is characterized as a 2e^?/10c bond from an Atoms-in-molecules analysis.     

Synthesis,characterization, spectrophotometric and electrochemistry studies,and DNA cleavage of copper(II) complexes of a new azacrown bis-macrocycle and its mono-cyclic analogue

A new azacrown bis-macrocycle (5) and its mono–cyclic analogue (7) were synthesized and characterized by FT-IR, ¹H NMR, ¹³C NMR, DEPT ¹³C NMR, MS, and elemental analysis. The reaction with copper(II) nitrate yielded the corresponding complexes, formulated as Cu(5)(NO₃)₂·3H₂O (8), and Cu(7)(NO₃)₂·2.5H₂O (9). Also the stoichiometries of the complexes were determined in alcoholic solution and the results show that for both complexes the ratio of ligand to metal was 1:1 in methanol. The redox behavior of both complexes has been studied by cyclic voltammetry in DMF. Cyclic voltamogram of 8 shows quasi-reversible Cu^II/Cu^I redox couple whereas 9 shows a reversible Cu^II/Cu^I redox couple. Mono- and bis-macrocycle copper(II) complexes (8 and 9 respectively) cleaved plasmid pGS2 DNA by using an oxidative mechanism with 3- mercaptopropionic acid (MPA) as the reductant under aerobic conditions. The bis-macrocycle copper(II) complex 8 showed higher cleavage efficiency than their mono-macrocycle analogue 9 at the same Cu²⁺ concentration.     

Synthesis, structure and property of three divalent metal complexes of the piperidinoacetyl-containing calix[4]arene

Three new mononuclear complexes [Cd(L)](ClO₄)₂·4(MeCN) (1) (L?=?5,11,17,23-tetra-t-butyl-25,26,27,28-tetrakis(piperidinocarbonylmethoxy)calix[4]arene), [Zn(L)](ClO₄)₂·4(MeCN)·CH₂Cl₂ (2), [Cu(L)](ClO₄)₂·3(MeCN)·Et₂O (3) have been synthesized and characterized by elemental analysis and X-ray single crystal diffraction (CCDC: 838342, 838343 and 838344). The results of the crystal structural analyses show that calix[4]arene backbones in 1, 2, 3 are fixed in the cone conformation while the divalent metal cations (Cd, Zn and Cu) are coordinated with the discrepant geometry. The cadmium ion in 1 is eight-coordinated with four carbonyl oxygen atoms and four ethereal oxygen atoms in the low rim of calix[4]arene, whereas zinc ion in 2 and copper ion in 1 are four-coordinated with the acyl oxygen atoms. The atomic net charges distribution and frontier molecular orbital energies were obtained by Gaussian 98 program with DFT method at B3LYP/lanl2dz level. Furthermore, the SOD-like activities of 3 were measured by xanthine/xanthine oxidase-NBT assay at pH 7.2 and 7.8.     

Experimental and theoretical studies of the topological and energy parameters in the crystal of 4,7-di-tert-butyl-2-phenyl-1,3,2-benzodioxaborole

The electron density distribution in the crystal of 4,7-di-tert-butyl-2-phenyl-1,3,2-benzodioxaborole (1) was examined both experimentally and theoretically. According to the theory “Atoms in Molecules”, the B-O bonds are “intermediate” interactions (?²γ(r) > 0, h _e(r) < 0), while the B-C(Ph), O-C, and C-C bonds are “shared” (?²γ(r) < 0, h _e(r) < 0). The energies of intra- and intermolecular interactions in the crystals were estimated. Compound 1 is inert to oxygen, which agrees with the low HOMO energy (?6.26 eV).