Neutral {CpFe II (CO) 2 [Sn II (Pc •3– )]} {Cp is cyclopentadienyl ( 1 , 2 ) or Cp* is pentamethylcyclopentadienyl ( 3 ); Pc: phthalocyanine}, {Cp*Fe II (CO) 2 [Sn II (Nc •3– )]} ( 4 , Nc: naphthalocyanine), and {CpFe II (CO) 2 [Sn II (TPP •3– )]} ( 5 , TPP: tetraphenylporphyrin) complexes in which CpFe II (CO) 2 fragments (Cp: Cp or Cp*) are coordinated to Sn II (macrocycle •3– ) have been obtained. The product complexes were obtained at the reaction of charge transfer from CpFe I (CO) 2 (Cp: Cp or Cp*) to [Sn II (macrocycle 2− )] to form the diamagnetic Fe II and paramagnetic radical trianionic macrocycles. As a result, these formally neutral complexes contain S = 1/2 spins delocalized over the macrocycles. This provides alternation of the C–N imine or C–C meso bonds in the macrocycles, the appearance of new bands in the near-infrared spectra of the complexes, and blue shift of both Soret and Q-bands. The {CpFe II (CO) 2 Sn II (macrocycle •3– )} units (Cp: Cp or Cp*, macrocycle: Pc or Nc) form closely packed π-stacking dimers in 1 and 3 or one-dimensional chains in 2 and 4 with effective π–π interaction between the macrocycles. Such packing allows strong antiferromagnetic coupling between S = 1/2 spins. Magnetic interaction can be described well by the Heisenberg model for the isolated dimers in 1 and 3 with exchange interaction J / k B = −78 and −85 K, respectively. Magnetic behavior of 2 and 4 is described well by the model that includes contributions from an antiferromagnetically coupled S = 1/2 dimer ( J intra ) and a Heisenberg S = 1/2 chain with alternating antiferromagnetic spin exchange between the neighbors ( J inter ). Compound 2 demonstrates large intradimer interaction of J intra / k B = −54 K and essentially weaker interdimer exchange interactions of J ...
Coordination of tin(II) phthalocyanine to transition metal carbonyl clusters in neutral {Sn(II){Pc(2-)}}(0) or radical anion {Sn(II){Pc(•3-)}}(-) states is reported. Direct interaction of Co4(CO)12 with {Sn(II){Pc(2-)}}(0) yields crystalline complex {Co4(CO)11·Sn(II){Pc(2-))} (1)....
BackgroundThe steady rise in the spread of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) requires rapid and reliable methods to identify resistant strains. The current molecular methods to detect MTB resistance to second-line drugs either do not cover an extended spectrum of mutations to be identified or are not easily implemented in clinical laboratories. A rapid molecular technique for the detection of resistance to second-line drugs in M. tuberculosis has been developed using hybridisation analysis on microarrays.MethodsThe method allows the identification of mutations within the gyrA and gyrB genes responsible for fluoroquinolones resistance and mutations within the rrs gene and the eis promoter region associated with the resistance to injectable aminoglycosides and a cyclic peptide, capreomycin. The method was tested on 65 M. tuberculosis clinical isolates with different resistance spectra that were characterised by their resistance to ofloxacin, levofloxacin, moxifloxacin, kanamycin and capreomycin. Also, a total of 61 clinical specimens of various origin (e.g., sputum, bronchioalveolar lavage) were tested.ResultsThe sensitivity and specificity of the method in the detection of resistance to fluoroquinolones were 98% and 100%, respectively, 97% and 94% for kanamycin, and 100% and 94% for capreomycin. The analytical sensitivity of the method was approximately 300 genome copies per assay. The diagnostic sensitivity of the assay ranging from 67% to 100%, depending on the smear grade, and the method is preferable for analysis of smear-positive specimens.ConclusionsThe combined use of the developed microarray test and the previously described microarray-based test for the detection of rifampin and isoniazid resistance allows the simultaneous identification of the causative agents of MDR and XDR and the detection of their resistance profiles in a single day.
Reduction of neutral metal clusters (Co4(CO)12, Ru3(CO)12, Fe3(CO)12, Ir4(CO)12, Rh6(CO)16, {CpMo(CO)3}2, {Mn(CO)5}2) by decamethylchromocene (Cp*2Cr) or sodium fluorenone ketyl in the presence of cryptand[2.2.2] and DB‐18‐crown‐6 was studied. Nine new salts with paramagnetic Cp*2Cr+, cryptand[2.2.2](Na+), and DB‐18‐crown‐6(Na+) cations and [Co6(CO)15]2– (1, 2), [Ru6(CO)18]2– (3–4) dianions, [Rh11(CO)23]3– (6) trianions, and new [Ir8(CO)18]2– (5) dianions were obtained and structurally characterized. The increase of nuclearity of clusters under reduction was shown. Fe3(CO)12 preserves the Fe3 core under reduction forming the [Fe3(CO)11]2– dianions in 7. The [CpMo(CO)3]2 and [Mn(CO)5]2 dimers dissociate under reduction forming mononuclear [CpMo(CO)3]– (8) and [Mn(CO)5]– (9) anions. In all anions the increase of negative charge on metal atoms shifts the bands attributed to carbonyl C–O stretching vibrations to smaller wavenumbers in agreement with the elongation of the C–O bonds in 1–9. In contrast, the M–C(CO) bonds are noticeably shortened at the reduction. Magnetic susceptibility of the salts with Cp*2Cr+ is defined by high spin Cp*2Cr+ (S = 3/2) species, whereas all obtained anionic metal clusters and mononuclear anions are diamagnetic. Rather weak magnetic coupling between S = 3/2 spins is observed with Weiss temperature from –1 to –11 K. That is explained by rather long distances between Cp*2Cr+ and the absence of effective π–π interaction between them except compound 7 showing the largest Weiss temperature of –11 K. The {DB‐18‐crown‐6(Na+)}2[Co6(CO)15]2– units in 2 are organized in infinite 1D chains through the coordination of carbonyl groups of the Co6 clusters to the Na+ ions and π–π stacking between benzo groups of the DB‐18‐crown‐6(Na+) cations.
Reduction of copper(II) octafluoro- {CuII(F8Pc)} and hexadecafluorophthalocyanines {CuII(F16Pc)} by NaCpCo(CO)2 in the presence of cryptand[2.2.2] yields new crystalline {cryptand(Na+)}[CuII(F8Pc)•3-]- 2C6H4Cl2(1) and {cryptand(Na+)}2[CuII(F16Pc)4-]2- C6H14 (2) salts. Together with two previously characterized...
The interaction of {Cryptand(K+)}(C60 •–) with Fe3(CO)12 produced {Cryptand(K+)}2{Fe(CO)2-μ 2-η 2,η 2-C60}2 2–·2.5C6H4Cl2 (1) as the first negatively charged iron-bridged fullerene C60 dimer. The bridged iron atoms are coordinated to two 6–6 bonds of one C60 hexagon with short and long C(C60)–Fe bonds with average lengths of 2.042(3) and 2.088(3) Å. Fullerenes are close to each other in the dimer with a center-to-center interfullerene distance of 10.02 Å. Optical spectra support the localization of negative electron density on the Fe2(CO)4 units, which causes a 50 cm–1 shift of the CO vibration bands to smaller wavenumbers, and the C60 cages. Dimers are diamagnetic and electron paramagnetic resonance silent and have a singlet ground state resulting from the formation of an Fe–Fe bond in the dimer with a length of 2.978(4) Å. According to density functional theory calculations, the excited triplet state is higher than the ground state by 6.5 kcal/mol. Compound 1 shows a broad near-infrared band with a maximum at 970 nm, which is attributable to the charge transfer from the orbitals localized mainly on iron atoms to the C60 ligand.
Herein, a new method for the preparation of anionic hexaazatrinaphthylene (HATNA) coordination complexes was developed. The reduced HATNA coordinated three FeIICl2 units for the formation of (CV+)2{HATNA(FeIICl2)3}2− ⋅ 3.5 C6H4Cl2 (1) (CV+ is a cationic form of crystal violet). The FeII atoms had a high S=2 spin state and were arranged in nearly equilateral triangles at a distance of approximately 7 Å. The χMT value of 1 was 9.70 emu⋅K/mol at 300 K, exceeding the calculated spin‐only value of three independent high‐spin FeII centers (S=2) (9.00 emu⋅K/mol). A strong antiferromagnetic exchange was observed between FeII atoms through the diamagnetic HATNA units since Weiss temperature is −98 K. Magnetic behavior of 1 was modelled by PHI package obtaining the exchange interaction constant J=−4.6 cm−1 and zero‐field splitting parameter D=5.6 cm−1 at g=2.23. Arrangement of magnetic centers in the equilateral triangles supposes that some degree of spin frustration exists in 1. Crystal structures of two phases of pristine HATNA molecule are also reported.
New ionic complex {Co(+)(dppe)(2)}·(C(60)˙(-))·(C(6)H(4)Cl(2))(2) (1) was obtained by the reduction of a Co(dppe)Br(2) and C(60) mixture by TDAE in o-dichlorobenzene followed by precipitation of crystals by hexane. Optical and EPR spectra of 1 indicated the formation of C(60)˙(-) radical anions and diamagnetic Co(+)(dppe)(2) cations. The structure of 1 solved at 100(2) K involves chains of C(60)˙(-) arranged along the lattice a-axis with a center-to-center distance of 10.271 Å. The chains are separated by bulky Co(+)(dppe)(2) cations and solvent molecules. All components of 1 are well ordered allowing the distortion of the C(60)˙(-) radical anion to be analyzed. An elongation of the C(60)˙(-) sphere by 0.0254(2) was found. It is essentially smaller than those in the salts (Cp*(2)Ni(+))·(C(60)˙(-))·CS(2) and (PPN(+))(2)·(C(60)(2-)) with greater distortion of the fullerene cage. The calculation of the electronic structure of fullerene by the extended Hückel method showed slight splitting of the C(60) LUMO, due to the distortion, by three levels. Two levels are located 180 and 710 cm(-1) higher than the ground level. The averaged 6-6 and 5-6 bonds in C(60)˙(-) with lengths of 1.397(2) and 1.449(2) Å are close to those determined for the C(60)(2-) dianions in (PPN(+))(2)·(C(60)(2-)), but are slightly longer and shorter, respectively, than the length of these bonds in neutral C(60).
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