Trigonal Bipyramidal Coordination Research Articles

Dihydroxybenzoic acids as polydentate ligands in phenylantimony (V) complexes

The compounds Ph4Sb[O(O)CC6H3(OH)2-2,5] (1), Ph4Sb[O(O)CC6H3(OH)2-2,6] (2) and [Ph4Sb]+[Ph4Sb(O2C6H3CO2H)]−(3) were obtained through the interaction of pentaphenylantimony with 2,5-; 2,6- and 2,3-dihydroxybenzoic acids in toluene. The structure of synthesized compounds and the coordination type of antimony atoms in 1, 2 and 3 depend on the location of hydroxyl groups in the benzene ring. The antimony atoms in 1 and 2 have distorted trigonal-bipyramidal coordination, through to different degrees. The antimony atom in the anion of compound 3 is hexacoordinated with [C4O2]− surroundings. The compounds 1,2 and 3 have been characterized by elemental analysis, IR- and NMR-spectroscopy, X-ray analysis.

Crystal structure and Hirshfeld surface analysis of (μ-2-{4-[(carboxyl-atometh-yl)carbamo-yl]benz-amido}-acetato-κ2 O:O')bis-[bis-(1,10-phenanthroline-κ2 N,N')copper(II)] dinitrate N,N'-(1,4-phenyl-enedicarbon-yl)diglycine monosolvate octa-hydrate.

The centrosymmetric binuclear complex cation of the title compound, [Cu2(C12H10N2O6)(C12H8N2)4](NO3)2·C12H12N2O6·8H2O, is composed of a CuII atom with a distorted trigonal-bipyramidal coordination environment defined by four N atoms from two bidentate 1,10-phenanthroline ligands and one oxygen atom from one-half of the monodentate N,N'-(1,4-phenyl-enedicarbon-yl)diglycinate anion. The asymmetric unit is completed by one-half of the N,N'-(1,4-phenyl-enedicarbon-yl)diglycine solvent mol-ecule, which is located on a centre of inversion, by one nitrate counter-anion and four water mol-ecules. In the crystal, the cationic complexes are linked via inter-molecular π-π stacking and through lone-pair⋯π inter-actions involving the N,N'-(1,4-phenyl-enedicarbon-yl)diglycinate anion and the phenanthroline ligands. The N,N'-(1,4-phenyl-enedicarbon-yl)diglycine solvent mol-ecule is involved in classical and non-classical hydrogen-bonding inter-actions, as well as π-π stacking inter-actions. The centroid-to-centroid distances between aromatic entities are in the range 3.5402 (5)-4.3673 (4) Å. The crystal structure is stabilized by further C-H⋯O contacts as well as by O-H⋯O and N-H⋯O hydrogen bonds between water mol-ecules, the nitrate anions, the N,N'-(1,4-phenyl-enedicarbon-yl)diglycinate ligands, N,N'-(1,4-phenyl-enedicarbon-yl)diglycine solvent mol-ecules and phenanthroline ligands, giving rise to a supra-molecular framework. A Hirshfeld surface analysis was carried out to qu-antify these inter-actions.

More crystal field theory in action: the metal-4-picoline (pic)-sulfate [M(pic)x]SO4 complexes (M= Fe, Co, Ni, Cu, Zn, and Cd).

Seven crystal structures of five first-row (Fe, Co, Ni, Cu, and Zn) and one second-row (Cd) transition metal-4-picoline (pic)-sulfate complexes of the form [M(pic)x]SO4 are reported. These complexes are catena-poly[[tetrakis(4-methylpyridine-κN)metal(II)]-μ-sulfato-κ2O:O'], [M(SO4)(C6H7N)4]n, where the metal/M is iron, cobalt, nickel, and cadmium, di-μ-sulfato-κ4O:O-bis[tris(4-methylpyridine-κN)copper(II)], [Cu2(SO4)2(C6H7N)6], catena-poly[[bis(4-methylpyridine-κN)zinc(II)]-μ-sulfato-κ2O:O'], [Zn(SO4)(C6H7N)2]n, and catena-poly[[tris(4-methylpyridine-κN)zinc(II)]-μ-sulfato-κ2O:O'], [Zn(SO4)(C6H7N)3]n. The Fe, Co, Ni, and Cd compounds are isomorphous, displaying polymeric crystal structures with infinite chains of MII ions adopting an octahedral N4O2 coordination environment that involves four picoline ligands and two bridging sulfate anions. The Cu compound features a dimeric crystal structure, with the CuII ions possessing square-pyramidal N3O2 coordination environments that contain three picoline ligands and two bridging sulfate anions. Zinc crystallizes in two forms, one exhibiting a polymeric crystal structure with infinite chains of ZnII ions adopting a tetrahedral N2O2 coordination containing two picoline ligands and two bridging sulfate anions, and the other exhibiting a polymeric crystal structure with infinite chains of ZnII ions adopting a trigonal bipyramidal N3O2 coordination containing three picoline ligands and two bridging sulfate anions. The structures are compared with the analogous pyridine complexes, and the observed coordination environments are examined in relation to crystal field theory.

Synthesis, characterization and crystal structures of copper(II), zinc(II) and vanadium(V) complexes, derived from 3-methyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide, with antibacterial activity

Three copper(II), zinc(II), and vanadium(V) complexes, [CuL(HL)]ClO4 (1), [ZnL2] (2) and [VO2L] (3), where L is the anionic form of 3-methyl-N′-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL), were prepared and characterized by IR, UV–vis and single-crystal X-ray determination. X-ray analysis indicates that the complexes are mononuclear species, with the Cu and Zn ions in 1 and 2 in octahedral coordination, and with the V ion in 3 in trigonal bipyramidal coordination. The hydrazone compound and the three complexes were evaluated for antibacterial activities. The copper complex has effective activities.

Crystal structure of chlorido-{tris-[2-(iso-propyl-sulfan-yl)phen-yl]phosphane-κ4 P,S,S',S''}nickel(II) tri-fluoro-methane-sulfonate.

The complex cation of the title compound, [NiCl{P(C6H4-2-S-i-Pr)3}](CF3SO3), has a slightly distorted trigonal-bipyramidal coordination geometry in which three S atoms are located in the equatorial plane, and one P and one Cl atom in the apical positions. In the cation, there are two intra-molecular C-H⋯S hydrogen bonds. In the crystal, there are some inter-molecular C-H⋯O and C-H⋯F hydrogen bonds formed between the cation and the anion. The tri-fluoro-methane-sulfonate anion and one of the methyl groups are both disordered over two sets of sites with occupancies of 0.629 (17):0.371 (17) and 0.786 (14):0.214 (14), respectively.

Crystal structure of a 1:1 adduct of tri-phenyl-tin chloride with 3-cyclo-hexhyl-2-phenyl-1,3-thia-zolidin-4-one.

In the centrosymmetric (racemic) title compound, chlorido-(3-cyclo-hexhyl-2-phenyl-1,3-thia-zolidin-4-one-κO)tri-phenyl-tin(IV), [Sn(C6H5)3Cl(C15H19NOS)], the tin(IV) atom exhibits a trigonal-bipyramidal coordination geometry with the three phenyl groups in equatorial positions and the chloride anion and ligand oxygen atom present at axial sites [O-Sn-Cl = 175.07 (14)°]. The thia-zolidinone ring of the ligand adopts an envelope conformation with the S atom as the flap. The dihedral angles between the heterocycle ring plane (all atoms) are 44.3 (9)° with respect to the pendant C-phenyl plane and 34.3 (11)° to the N-cyclo-hexyl ring (all atoms). The C-phenyl and N-cyclo-hexyl ring are close to orthogonal to each other, with a dihedral angle of 81.1 (4)° between them. In the crystal, mol-ecules are linked by weak C-H⋯Cl hydrogen bonds to generate [001] chains.

Triarylbismuth Dicarboxylates Ar3Bi[OC(O)R]2, Ar = p-Tol, R = CH2Cl; Ar = Ph, R = C6H4OMe-2, CH=CHPh

Triarylbismuth dicarboxylates Ar3Bi[OC(O)R]2, Ar = p-Tol, R = CH2Cl (I); Ar = Ph, R = C6H4OMe-2 (II), CH=CHPh (III) have been synthesized by the reactions of tri(para-tolyl)bismuth with monochloroacetic acid and triphenylbismuth with 2-methoxybenzoic and cinnamic acids in methyl-tert-butyl ether in the presence of tert-butyl hydroperoxide with a high yield. The Bi atoms in complexes I–III have a distorted trigonal bipyramidal coordination with carboxylate ligands in axial positions (OBiO angles, 171.06(6)° (I), 170.46(12)° (II), 175.39(8)° (III)). The Sb-O and Sb-C bond lengths are 2.283(2), 2.288(2) A and 2.185(2)–2.199(2) A (I), 2.265(7), 2.268(7) A and 2.194(7)–2.218(8) A (II), and 2.310(2), 2.310(2) A and 2.200(2)–2.210(3) A (III). Molecules of complexes I–III have intramolecular contacts between the Bi atom and the O atoms of carbonyl groups: the Bi⋯O(=C) distances are 2.990(2), 2.985(3) A (I), 2.753(8), 2.739(8) A (II), and 2.688(2) A (III). The structural organization in crystals of complexes I–III is caused by weak inter-molecular hydrogen bonds H⋯O of 2.61–2.65 A (I), 2.47–2.50 A (II), and 2.56 A (III).

Inorganic pigments with transition metal chromophores at trigonal bipyramidal coordination: Y(In,Mn)O3 blues and beyond

The discovery of a brilliant-blue color through Mn3+ substitution in trigonal-bipyramidal (TBP) sites of hexagonal YInO3 has led to a search for other inorganic pigments with chromophore ions at TBP coordination. Introducing transition metal cations Fe3+, Cu2+/Ti4+ and Mn3+/Zn2+/Ti4+ into the TBP sites in YInO3 has produced various colors from orange, green to purple. These indium-containing samples are successfully prepared via several synthetic routes including solid state reactions, modified Pechini method and microwave radiation. All pigments show excellent near infrared reflectance comparable to that of commercial TiO2. Cheaper hexagonal YMO3 host materials with TBP coordination such as citrate-prepared hexagonal YAlO3 (M = Al) have failed to produce the anticipated vivid color due to the destruction of TBP sites caused by carbonate incorporation. We conclude that the resulting intense colors of pigments are due to the crystal field splitting associated with the TBP coordination and the short apical M–O bonds (M = Mn, Fe, Cu). Other colored compounds containing TBP coordination are briefly reviewed. Blue and/or bluish-purple colors are found when Mn3+, Co2+ or Cu2+ are substituted into TBP sites of metal oxides that are not hexagonal YMO3-based.

Synthesis and crystal structure of bicopper(II) complexes: The influence of bridging ligands on DNA/BSA binding behaviors and in vitro antitumor activity

Two new μ-oxamide or μ-oxamate bridged bicopper(II) complexes, [Cu2(mapox)(bpy)2](ClO4)2 (1) and Cu2(mapoa)(CH3OH)(bpy)2(pic)2·0.5H2O (2) (H2mapox = N,N′-bis[3-(methylamino)propyl]-oxamide, H2mapoa = N-[3-(methylamino)propyl]oxamate, bpy = 2,2′-bipyridine, pic = picrate anions), have been synthesized and characterized by elemental analyses, molar conductance measurement, spectroscopic studies and single-crystal X-ray diffraction. In complex 1, both the copper(II) atoms acquire a square-pyramidal coordination geometry. The distance between Cu1 and Cu2 atoms is 5.2541(8) Å. The structure of complex 2 contains two bicopper(II) cations [Cu2(mapoa)(CH3OH)(bpy)2]2+, in which the Cu atoms acquire distorted square-pyramid coordination geometry (Cu1, Cu2, Cu4) or distorted trigonal bipyramid coordination geometry (Cu3). The Cu⋯Cu separations are 5.2316(8) Å (Cu1, Cu2) and 5.2187(7) Å (Cu3, Cu4), respectively. The interaction between complexes 1 and 2 and herring Sperm DNA (HS-DNA) were studied by using UV absorption and fluorescence spectra, electrochemical techniques and viscometry. The results indicated that both of the two complexes could bind to HS-DNA by intercalation with the order 1 > 2. Protein binding properties investigations reveal that the two complexes could bind to bovine serum albumin (BSA) by the static quenching mechanism. The in vitro cytotoxicities experiments reveal that complex 1 exhibit better growth-inhibitory effects than complex 2 on human hepatocellular carcinoma cell SMMC-7721 and human lung adenocarcinoma cell A549.

Tri-para-Tolylantimony Dicarboxylates (4-MeC6H4)3Sb[OC(O)R)]2, R = C6H4(NO2-3), C6H3(NO2)2-3,5, CH2Br: Synthesis and Structure

Tri-para-tolylantimony bis(3-nitrobenzoate) (I), tri-para-tolylantimony bis(3,5-dinitrobenzoate) (II), and tri-para-tolylantimony bis(bromoacetate) (III), in which the Sb atoms have a trigonal bipyramidal coordination according to X-ray diffraction analysis, have been synthesized by the reaction of tri-para-tolylantimony (4-MeC6H4)3Sb with 3-nitrobenzoic, 3,5-dinitrobenzoic, and bromoacetic acids in the presence of tert-butyl hydroperoxide. The OSbO axial angles are 171.83(12)°, 173.06(9)°, and 173.82(10)°. The Sb-O and Sb-C bond lengths are 2.109(3), 2.123(3), and 2.095(4)–2.111(5) A in I, 2.108(2), 2.133(3), and 2.095(4)–2.103(3) A in II, 2.126(3), 2.133(3), and 2.102(3)–2.115(3) A in III. The Sb⋯O intramolecular distances (3.105(5), 3.168(5) in I, 3.060(4), 3.096(4) in II, 3.069(4), 3.100(4) ⋯ in III) are ∼0.5 ⋯ smaller than the sum of the antimony and oxygen van der Waals radii.

Synthesis and Structure of μ2-Oxobis(carboxylatotriarylantimony)

Binuclear antimony compounds with a bridging oxygen atom [Ph3SbOC(O)R]2O (R = CF2CF3, CF2CF2CF3), [(4-МеC6H4)3SbOC(O)CF2CF3]2O, [(3-FC6H4)3SbOC(O)R]2O (R = C6F5, CF2CF3) have been synthesized by reacting equimolar amounts of triarylantimony, carboxylic acid and tert-butyl hydroperoxide in diethyl ether. According to X-ray diffraction data, in the molecules of compounds obtained, the Sb atoms have a trigonal bipyramid coordination with carboxylate ligands and a bridging oxygen atom in axial positions. The intramolecular distances Sb···O with a carbonyl oxygen atom are less than the sum of the van der Waals radii of Sb and O by ~0.2–0.4 A.

Синтез и рентгеноструктурное исследование сольвата бис[μ-оксо-три(2-метилфенил)сурьмы] c бензолом

Previously known bis [μ-oxo-tri(2methylphenyl)antimony] was synthesized by the reaction of tris (2-methylphenyl)antimony with tret -butyl hydroperoxide (1:1 molar ratio) in DMSO. A single crystal of the [(2 MeC 6 H 4 ) 3 SbO] 2 ·PhH ( 1 ) solvate was obtained by recrystallization from the mixture of benzene and heptane (3:1). The structure of solvate 1 has been investigated by X-ray diffraction study and IR spectroscopy. Absorption bands of hydroxy groups are not detected in the IR spectrum of solvate 1 . Stretching vibrations of the Sb-O moiety and cyclic fragment υ as (Sb 2 O 2 ) are observed at 542–668 cm –1 and 653, 636 cm –1 , respectively. Deformation vibrations δ(Sb 2 O 2 ) are attributed to the band at 482 cm –1 . According to X-ray data, the crystals of compound 1 are triclinic with the P -1 space group. Antimony atoms have a trigonal bipyramidal coordination. Two aryl substituents and the m 2 -bridged oxygen atom are in the equatorial plane of antimony atoms, and the third aryl substituent and the second m 2 -bridged oxygen atom are in axial positions. The sum of the CSbC and OSbC equatorial angles is 357.84º, and the OSbC axial angle is 162.89º. The cyclic Sb 2 O 2 fragment of the molecule is flat. The Sb-C, Sb-O bond lengths and the SbOSb, OSbO valence angles are close to the previously reported unsolvated oxide. Structural organization in the crystals is characterized by the presence of intermolecular contacts C···H (2.893 Å) involving atoms of the phenyl rings of different molecules in the dimer oxide. Solvent molecules do not participate in the formation of short contacts and form a layer between the dimer oxide molecules bonded in a “chain” due to intermolecular bonds.

Строение аддукта бис(хлорацетата) три(о-толил)висмута с хлоруксусной кислотой

An inclusion complex of tri( o -tolyl) bismuth bis (chloroacetate) with chloroacetic acid ( o -Tol) 3 Bi[OC(O)CH 2 Cl] 2 HOC(O)CH 2 Cl ( 1 ) was synthesized from tri( o -tolyl)bismuth bis (chloroacetate) and chloroacetic acid in benzene. The structure of adduct 1 was determined by X-ray structural analysis. X-ray analysis of the compound crystal was performed on a D8 Quest Bruker automatic four-circle diffractometer (MoKα radiation, λ = 0.71073 Å, graphite monochromator) at 292 K. 1, P 2 1 / с , a = 10.8054(2), b = 14.2764(3), c = 12.9748(3) Å, β = 102.677(2)º, V = 1952.73(7) Å 3 , Z = 4, 0.209 × 0.172 × 0.116 mm, 3.371 30.508º, intervals of reflection indices –15 ≤ h ≤ 15, –20 ≤ k ≤ 20, –18 ≤ l ≤ 18, measured reflections 38696, independent reflections 5964, refinement variables 299, GOOF 1.13, R 1 = 0.0348, wR 2 = 0.076, residual electron density –0.523 / 0.777 e / A 3 , (calc.) 1.445 g/cm 3 . In the structure of crystal 1 the Bi atoms have a distorted trigonal bipyramidal coordination with the oxygen atoms in axial positions. The OBiO axial angle in 1 is 175.24 (11). The lengths of the BiO and BiC bonds are 2.258(3)–2.302(3) and 2.211(5), 2.228(5) Å. The chloroacetic acid molecule is linked by a coordination bond through the carboxyl hydrogen atom to the carbonyl oxygen atom of one of the two carboxyl groups of triarylbismuth dicarboxylate. The intermolecular OHO distances (1.9 Å) are shorter than the sum of van der Waals radii O and H by 0.8 Å.

Synthesis and Structure of µ2-Oxo-Bis [(Pentafluoropropionato)-Tris(5-Bromo-2-Methoxyphenyl)Antimony

The synthesis of μ 2 -oxo- bis [(pentafluoropropionato) tris (5-bromo-2-methoxy­phenyl)­antimony] ( 1 ) has been curried out by the oxidative addition reaction of tris (5-bromo-2-methoxyphenyl)antimony with pentafluoropropionic acid in the presence of hydrogen peroxide at an equimolar ratio of reactants. The compound is characterized by IR spectroscopy and X-ray diffraction analysis. According to X-ray diffraction data, there are two types of crystallographically independent molecules with slightly different geometrical parameters in the crystal. The antimony atoms in each molecule are linked by the bridging oxygen atom (the SbOSb angle is 167.6(7)°). The trigonal bipyramidal coordination of antimony atoms is distorted; the axial OSbO angles are 175.9(4)°, 174.5(4)° for Sb(1) and Sb(2) atoms, respectively. The sums of valence CSbC angles in the equatorial planes are 359.6(6)° and 356.4(6)°. The mean values of the Sb(1)–C and Sb(2)–C bond lengths are 2.12(2) Å, the Sb–O( μ 2 ) distances are 1.89(1), 1.98(1) Å. The carboxylate ligands in each molecule are monodentate. The distances between the antimony atoms and the corresponding terminal oxygen atoms are 2.22(1), 2.39(1) Å, the Sb···O=C distances are 3.38(2), 3.71(1) Å. The d(Sb···O=C)/d(Sb–О) ratios, which can be used to estimate the asymmetry of the ligand related to metal atom coordination, are 1.67 and 1.41. In crystal 1 there are such contacts as Sb···OMe (2.88(1)–3.16(1), 3.01(1)–3.20(1) Å), hydrogen bonds involving halogen atoms H···F (2.16, 2.50, 2.58 Å), H···Br (2.92, 2.96, 3.04 Å) and carbonyl oxygen atoms H···О (2.43, 2.59 Å), as well as halogen···halogen F···F interactions (2.70, 2.71 Å).

Синтез и строение гидрата 2-[(6-аминопиримидин-4(3Н)-он-2-ил)сульфанил]ацетата тетрафенилсурьмы

Tetraphenylantimony 2-[(6-Aminopyrimidine-4(3 H )-one-2-yl)sulfonyl]acetate, obtained due to substitution of the hydrogen atom by the Ph 4 Sb-fragment in the carboxylic group, is a product of the reaction between pentaphenylantimony and 2-[(6-aminopyrimidine-4(3 H )-one-2-yl)sulfonyl]acetic acid. The compound has been isolated in the form of a hydrate with 78 % yield and represents colourless crystals with the melting point 197 °С. The compound has been characterized by IR-spectroscopy and X-ray analysis. The absorption bonds of the carbonyl groups in the cycle and acid fragment are present in the IR-spectra at the frequency 1629 and 1603 сm −1 ,respectively. According to the X-ray analysis, carried out on a D8 QUEST Bruker diffractometer, the compound unit cells parameters are: triclinic syngony, P group of symmetry; а = 9.551(3), b =13.469(3), c = 14.484(5) Å, α = 86.355(11)°, β = 74.421(18)°, γ = 76.483(10)°, V = 1745.0(9) Å 3 , ρ calc = 1.234 g/cm 3 . The antimony atom has a distorted trigonal bipyramidal coordination. The OSbC axial angle equals 179.42(10)°, the sum of angles in the equatorial plane equals 357.0(13)°. The Sb–C axial bond and equatorial bonds equal 2.175(3) Å and 2.107(3)−2.139(3) Å, respectively. The Sb−O bond length equals 2.253(2) Å. The single and double bond are not aligned (1.283(3) и 1.226(4) Å, respectively). The pyrimidine cycle is practically planar, the nitrogen and carbon atoms deviate from the middle plane by no more than 0.012 Å; the sulfur atom deviates from the middle plane by 0.106 Å.

Синтез и строение cольвата 2,6-пиридиндикарбоксилата бис(тетрафенилсурьмы) с толуолом

At interaction of pentaphenylantimony with 2,6-pyridinedicarboxylic acid (mole ratio 1:1 or 2:1) in a toluene solution, bis (tetraphenylantimony) 2,6-pyridinedicarboxylate toluene solvate (1) has been obtained for the first time (yield 72%, colorless crystals, m.p. 170 °C). The compound 1 has been characterized by IR-spectroscopy, elemental and X-ray analysis. The absorption band of a carbonyl group with the frequency 1620 cm –1 is present in the IR-spectrum, shifting towards the area of low-frequency oscillations in comparison with the spectrum of the acid (1701 cm –1 ). According to the data of X-ray analysis the unit cell crystallographic parameters of compound 1: triclinic syngony, the symmetry group P; a = 12.494(5), b = 13.788(5); c = 16.684(6) Å; V = 2550.5(16) Å3; Z = 2; ρ(calc.) = 1.455 g/сm 3 . The Sb(1) and Sb(2) atoms in a molecule have a distorted trigonal-bipyramidal coordination in different degrees. The CSb(1)O and CSb(2)O axial angles equal 178.41(10)° and 176.75(11)°, the CSb(1)C and CSb(2)C equatorial angles vary in the ranges 111.58(14)–125.24(13)°) and 103.44(13)−146.5(11)°. The Sb(1,2)−O bond lengths equal 2.301(2), 2.310(2) Å. The Sb(1,2)–Ceqv equatorial bonds (2.105(3)–2.112(3) Å and 2.140(3)–2.162(3) Å) are shorter than the Sb(1,2)–Cax axial one (2.177(3), 2.162(3) Å). The bidentate binding of carboxylate ligands is weak (the distance Sb(1)∙∙∙O(2) equals 3,263(4) Å) it has been proved by significant difference in the lengths of single (С–О 1.288(3), 1.261(4) Å) and double bonds (С=О 1.226(3), 1.236(4) Å) in the carboxylate groups. The pypidine ring nitrogen atom coordinates to the antimony atom (the distance Sb(2)∙∙∙N equals 2.947(3) Å).

Минорный продукт [Ph3Sb(Cl)O]3C• PhH в реакции перераспределения лигандов арильных производных пятивалентной сурьмы

One of the reaction products of triphenylantimony dichloride and triphenylantimony bis (2,4-dibromophenoxide) (1:1 mol.) in benzene in air is the compound of three-coordinated carbon [Ph 3 Sb(Cl)O] 3 C × PhH ( 1 ). The compound has been identified by IR spectroscopy and X-ray diffraction analysis. According to the X-ray diffraction analysis the target product is a benzene solvate [С 61 H 51 Cl 3 O 3 Sb 3 , М = 1303.65; the monoclinic system, space group P2 1 /c; a 17.17(2), b 18.75(2); c 17.322(18) A; α 90.00, β 90.58(5), γ 90.00 град.; V 5576(11) A 3 ; Z 4; µ 1.630 mm –1 ; F (000) 2580.0; crystal size 0.28 × 0.22 × 0.11 mm; 2θ for data collection 6.4 - 36.8 degrees; index ranges −15 ≤ h ≤ 15, −16 ≤ k ≤ 16, −15 ≤ l ≤ 15; total reflections 24392; independent reflections 3981; R int 0.0516; variables 632, GOOF 1.141; R 1 = 0.0392; wR 2 = 0.0912; residual electron density 0.43/–0.35 e/A 3 ]. The COSb angles in the compound 1 vary in the interval 123.3(8)-127.1(8)°. The C–O shortened distances (1.365(15)–1.385(15) A) compared to the sum of the covalent radii of carbon and oxygen atoms (1.51 A) indicate an increase in the multiplicity of these bonds. The abnormal reduction of Sb–O distances (1.986(7), 2.001(7), 2.011(7) A) in the neutral molecule 1 compared to the sum of the covalent radii of antimony and oxygen atoms (2.14 A) implies delocalization of the electron density in the CO 3 Sb 3 core. The Sb – Cl distances are slightly longer than the sum of the covalent radii of antimony and chlorine atoms and are longer than ones in triphenylantimony dichloride. The antimony atoms have a distorted trigonal-bipyramidal coordination with heteroatoms in axial positions. The formation of the crystal structure is due to the formation of weak hydrogen bonds such as С···Н (2.72-2.90 A) and Сl···Н (2.94 A). Complete tables of coordinates of atoms, bond lengths and valence angles are deposited at the Cambridge Structural Data Bank (No. 1851485; deposit@ccdc.cam.ac.uk; http:// www.ccdc.cam.ac.uk/data_request/cif).

Syntheses, Characterization and Crystal Structures of Schiff Base Zinc(II) Complexes with Antibacterial Activity

Two polynuclear zinc(II) complexes, [Zn2(L1)2(OH2)2] (1) and [ZnL2(μ1,1-N3)]n (2), where L1 is the dianionic form of N,N'-bis(3,5-difluoro-2-hydroxybenzylidene)-1,3-diaminopropane, and L2 is the monoanionic form of 2-[(2-dimethylaminoethylimino)methyl]-4,6-difluorophenol, have been prepared and structurally characterized by elemental analyses, IR and UV-Vis spectroscopy, as well as single-crystal X-ray diffraction. In complex 1, the Zn atom is in octahedral coordination, with the donor atoms of the Schiff base ligands L1 and one water O atom. In complex 2, the Zn atom is in trigonal-bipyramidal coordination, with the three donor atoms of the Schiff base ligand L2 and two azido N atoms. The complexes have strong antibacterial activity against B. subtilis and S. aureus.

Probing Hydrogen Bonding Interactions to Iron-Oxido/Hydroxido Units by 57 Fe Nuclear Resonance Vibrational Spectroscopy.

Hydrogen bonds (H-bonds) have been shown to modulate the chemical reactivities of iron centers in iron-containing dioxygen-activating enzymes and model complexes. However, few examples are available that investigate how systematic changes in intramolecular H-bonds within the secondary coordination sphere influence specific properties of iron intermediates, such as iron-oxido/hydroxido species. Here, we used 57 Fe nuclear resonance vibrational spectroscopy (NRVS) to probe the Fe-O/OH vibrations in a series of FeIII -hydroxido and FeIV/III -oxido complexes with varying H-bonding networks but having similar trigonal bipyramidal primary coordination spheres. The data show that even subtle changes in the H-bonds to the Fe-O/OH units result in significant changes in their vibrational frequencies, thus demonstrating the utility of NRVS in studying the effect of the secondary coordination sphere to the reactivities of iron complexes.

Probing Hydrogen Bonding Interactions to Iron‐Oxido/Hydroxido Units by 57 Fe Nuclear Resonance Vibrational Spectroscopy

Hydrogen bonds (H-bonds) have been shown to modulate the chemical reactivities of iron centers in iron-containing dioxygen-activating enzymes and model complexes. However, few examples are available that investigate how systematic changes in intramolecular H-bonds within the secondary coordination sphere influence specific properties of iron intermediates, such as iron-oxido/hydroxido species. Here, we used 57Fe nuclear resonance vibrational spectroscopy (NRVS) to probe the Fe-O/OH vibrations in a series of FeIII-hydroxido and FeIV/III-oxido complexes with varying H-bonding networks but having similar trigonal bipyramidal primary coordination spheres. The data show that even subtle changes in the H-bonds to the Fe-O/OH units result in significant changes in their vibrational frequencies, thus demonstrating the utility of NRVS in studying the effect of the secondary coordination sphere to the reactivities of iron complexes.