H2 Complexes Research Articles

Understanding functions of eEF1 translation elongation factors beyond translation. A proteomic approach.

Mammalian translation elongation factors eEF1A1 and eEF1A2 are 92% homologous isoforms whose mutually exclusive tissue-specific expression is regulated during development. The isoforms have similar translation functionality, but show differences in spatial organization and participation in various processes, such as oncogenesis and virus reproduction. The differences may be due to their ability to interact with isoform-specific partner proteins. We used the identified sets of eEF1A1 or eEF1A2 partner proteins to identify cell complexes and/or processes specific to one particular isoform. As a result, we found isoform-specific interactions reflecting the involvement of different eEF1A isoforms in different cellular processes, including actin-related, chromatin-remodeling, ribonuclease H2, adenylyl cyclase, and Cul3-RING ubiquitin ligase complexes as well as initiation of mitochondrial transcription. An essential by-product of our analysis is the elucidation of a number of cellular processes beyond protein biosynthesis, where both isoforms appear to participate such as large ribosomal subunit biogenesis, mRNA splicing, DNA mismatch repair, 26S proteasome activity, P-body and exosomes formation, protein targeting to the membrane. This information suggests that a relatively high content of eEF1A in the cell may be necessary not only to maintain efficient translation, but also to ensure its participation in various cellular processes, where some roles of eEF1A have not yet been described. We believe that the data presented here will be useful for deciphering new auxiliary functions of eEF1A and its isoforms, and provide a new look at the known non-canonical functions of this main component of the human translation-elongation machinery.

Elucidation of Charge Contribution in Iridium-Chelated Hydrogen-Bonding Systems

We present two iridium complexes 1H + and 2H + that contain cationic ligands to extend the knowledge of charge-assisted hydrogen bonding (CAHB), which counts among the strongest non-covalent bonding interactions. Upon protonation, both complexes were converted into new hydrogen-bonding arrays with various selectivity for respective H-bonding partners. This study compares the association strengths of four hydrogen-bonding co-systems, emphasizing the roles of CAHB in supramolecular systems. We determined that the cationic charge in these systems contributed up to 2.7 kJ mol−1 in the H-bonding complexation processes.

Theoretical studies on complexes with ammonia: comparison with H2O complexes: hydrogen bonding

High-level theoretical results for structures, dissociation energies and vibrational frequencies of the ammonia complexes NH3–N2, NH3–CO, NH3–O2, NH3–NO, NH3–H2, NH3–F2, NH3–HF, NH3–Ne, NH3–Ar, NH3–CO2, NH3–N2O and NH3–NH3 are reported, and compared with results for corresponding complexes of H2O. While complexes of H2O with N2, CO, NO, Ne, Ar and NH3 are hydrogen bonded, of the complexes with NH3 only NH3-NH3 qualifies. However, for NH3–CO, NH3–N2 and NH3-Ne structures with weak hydrogen bonding are predicted by present theoretical results. Structures of H2, F2, HF, CO2 and N2O complexes with NH3 are similar to those with H2O, not hydrogen bonded, having AB face N of NH3. Their dissociation energies De are close to those of H2O-AB. Due to complex formation, some large changes are noted in vibrational frequencies and infrared intensities, especially for the NH3 dimer and for NH3–HF.

Rotational spectroscopy and bound state calculations of deuterated NH3–H2 van der Waals complexes

Pure rotational transitions of the deuterated NH3–H2 weakly bound complexes formed by NH3/ND3 and H2/D2, namely ND3–H2, NH3–D2 and ND3–D2, have been detected. Three different techniques, a millimeter-wave intracavity jet OROTRON spectrometer, molecular beam Fourier transform microwave (FTMW) cavity spectrometer and the broadband chirped pulse (CP) FTMW spectrometer were used to record the spectra in the frequency range from 20 to 140 GHz. The double resonance method was additionally applied to extend the frequency range of the OROTRON spectrometer to lower and of the FTMW cavity spectrometer to higher frequencies. A search for the transitions of deuterated isotopologues and their assignments were based on the recent study of the main isotopic species NH3–H2 [L.A. Surin et al., Astrophys. J., 838, 27 (2017)] and further confirmed by the bound state calculations presented here. The measured line positions including hyperfine splitting due to the 14N nuclear spin of NH3/ND3 and the D nuclear spins of D2 were analysed in order to determine the molecular parameters and structure of the deuterated NH3–H2 complexes. This study provides an effective new probe of the intermolecular interaction between ammonia and dihydrogen, knowledge of which is important for numerical modelling of astrophysical environments.

H2 storage and equilibrium isotope effect for Be, Li, and Ti-doped closoborate complexes

This work reports hydrogen uptake capacity and equilibrium isotope effect (EIE) for the Be, Li, and Ti-doped closoborate (B6H6) complexes using first-principles calculations at MP2/6-311++G** level. The EIE was obtained using vibrational frequencies of H2 and D2-adsorbed B6H6M (M = Be, Li, and Ti) complexes at MP2/6-311++G** level. Two, three, and four H2/D2 molecules get adsorbed on B6H6Be, B6H6Li, and B6H6Ti respectively. The gravimetric H2(D2) uptake capacity of B6H6Be, B6H6Li, and B6H6Ti complexes is found to be 4.8(9.5), 7.2(13.44), and 6.3(11.94) wt% respectively. H2 adsorption is thermodynamically favorable on B6H6Ti at ambient conditions, whereas it is unfavorable on B6H6Li and B6H6Be complexes. Contribution from each vibrational mode in calculating the equilibrium isotope effect is obtained. The EIE calculated using vibrational frequencies for the B6H6Be(1H2/1D2), B6H6Be(2H2/2D2), B6H6Li(1H2/1D2), B6H6Li(2H2/2D2), B6H6Li(3H2/3D2), B6H6Ti(2H2/2D2), B6H6Ti(3H2/3D2), and B6H6Ti(4H2/4D2) complexes is found to be 0.56, 0.26, 0.76, 0.93, 1.05, 0.25, 0.05, and 0.75 respectively. In case of B6H6Ti(1H2) complex, the hydrogen is adsorbed in atomic form. It is found that D2 binds better than the H2 to the B6H6M (M = Be, Li, and Ti) complex.

Exploring the Reaction Mechanism of H2S Decomposition with MS3 (M = Mo, W) Clusters.

H2S is abundantly available in nature, and it is a common byproduct in industries. Molybdenum sulfides have been proved to be active in the catalytic decomposition of hydrogen sulfide (H2S) to produce hydrogen. In this study, density functional theory (DFT) calculations are carried out to explore the reaction mechanisms of H2S with MS3 (M = Mo, W) clusters. The reaction mechanism of H2S with MoS3 is roughly the same as that of the reaction with WS3, and the free-energy profile of the reaction with MoS3 is slightly higher than that of the reaction with WS3. The overall driving forces (−ΔG) are positive, and the overall reaction barriers (ΔGb) are rather small, indicating that such H2 productions are product-favored. MS3 (M = Mo, W) clusters have clawlike structures, which have electrophilic metal sites to receive the approaching H2S molecule. After several hydrogen-atom transfer (HAT) processes, the final MS4·H2 (IM-4) complexes are formed, which could desorb H2 at a relatively low temperature. The singlet product MS4 clusters contain the singlet S2 moiety, similar to the adsorbed singlet S2 on the surface of sulfide catalysts. The theoretical results are compared with the experiments of heterogeneous catalytic decomposition of H2S by MoS2 catalysts. Our work may provide some insights into the optimal design of the relevant catalysts.

Solution and Solid‐State Structure of the First NHC‐Substituted Rhenium Heptahydrides

The structure of three new bis(N‐heterocyclic carbene) heptahydride rhenium complexes ([ReH7(NHC)2] with NHC= IMes (2b) (1,3‐bis(2,4,6‐trimethyl phenyl) imidazol‐2‐ylidene), IMesCl2 (4b) (4,5‐dichloro‐1,3‐dihydro‐1,3‐bis(2,4,6‐trimethyl phenyl)‐2H‐imidazol‐2‐ylidene) BIMes (5b) (1,3‐Bis(2,4,6‐trimethylphenyl)‐benzo imidazole ylidene), and of the known complex [ReH7(PPh3)2] (1) (bis(triphenyl phosphine)‐rhenium heptahydride), and the one of their labelled counterparts 2c‐d7, 4c‐d7, and 5c‐d7, were established in solution. The compounds exchanged with HD (2 bar) at 60 °C in deuterated THF to produce statistically distributed isotopomers. This exchange pointed to the intermediacy of H2 complexes and dynamic systems with fast equilibration processes of all hydride positions. T1min measurements were run on 2b, 4b, 5b and 1 in deuterated methylcyclohexane: 2b T1min = 144 ms, 5b T1min = 127 ms, both at 203 K. For 4b two T1min values were obtained corresponding to the 1H‐NMR signals of the hydrides: T1min = 119 ms and T1min = 128 ms both at 203 K. The T1min values determined are typical of terminal rhenium polyhydrides and for 1 was reported a comparably short value of T1min (70 ms, [D8]toluene, at –73 °C), typical of complexes that contain dihydrogen ligands. D‐NMR T1min measurements were also run for the fully deuterated compounds 2c‐d7, 4c‐d7, 5c‐d7 and of 1c‐d7 allowing to calculate the ionicities of the metal hydride bonds. The Re‐D ionicity values were obtained from the Deuterium Quadrupole Coupling Constant (DQCC) determinations. They were in the range of 0.61–0.71 for the fully labelled complexes: 2c‐d7: T1min = 15 ms, i = 61 %; 4c‐d7: (A) T1min = 20 ms, i = 67 %, (B) T1min = 41 ms, i = 77 %; 5c‐d7: T1min = 24 ms, i= 70 %; and 1c‐d7: T1min = 26 ms, i = 71 %. Single crystal X‐ray diffraction studies on 4b enabled us to refine the hydride positions with only restraints in the bond lengths and thermal parameters. The X‐ray solid structure resembles a pseudo‐capped square antiprismatic geometry.

A computational study of hydrogen dimers in giant-planet infrared spectra

The absorption due to H2–H2 complexes is investigated theoretically. The potential and dipole surfaces for the complex are taken from the literature. Quantum dynamical calculations of the roto-translational absorption spectrum are performed. Special attention is paid to the fine features due to hydrogen dimers, (H2)2, at the centers of the collision-induced rotational S(0) and S(1) transitions. The computed absorption coefficients are used to analyze the spectra of the four giant planets of our solar system.

Ab initio studies of the ground and first excited states of the Sr-H2 and Yb-H2 complexes.

Accurate intermolecular potential-energy surfaces (IPESs) for the ground and first excited states of the Sr-H2 and Yb-H2 complexes were calculated. After an extensive methodological study, the coupled cluster with single, double, and non-iterative triple excitation method with the Douglas-Kroll-Hess Hamiltonian and correlation-consistent basis sets of triple-ζ quality extended with 2 sets of diffuse functions and a set of midbond functions were chosen. The obtained ground-state IPESs are similar in both complexes, being relatively isotropic with two minima and two transition states (equivalent by symmetry). The global minima correspond to the collinear geometries with R = 5.45 and 5.10 Å and energies of -27.7 and -31.7 cm-1 for the Sr-H2 and Yb-H2 systems, respectively. The calculated surfaces for the Sr(3P)-H2 and Yb(3P)-H2 states are deeper and more anisotropic, and they exhibit similar patterns within both complexes. The deepest surfaces, where the singly occupied p-orbital of the metal atom is perpendicular to the intermolecular axis, are characterised by the global minima of ca. -2053 and -2260 cm-1 in the T-shape geometries at R = 2.41 and 2.29 Å for Sr-H2 and Yb-H2, respectively. Additional calculations for the complexes of Sr and Yb with the He atom revealed a similar, strong dependence of the interaction energy on the orientation of the p-orbital in the Sr(3P)-He and Yb(3P)-He states.

An enzyme-free sensitive electrochemical microRNA-16 biosensor by applying a multiple signal amplification strategy based on Au/PPy–rGO nanocomposite as a substrate

In present study, a sensitive and effective electrochemical microRNA (miRNA) sensing platform is successfully developed by integrating gold nanoparticles/polypyrrole-reduced graphene oxide (Au/PPy-rGO), catalyzed hairpin assembly (CHA) and hybridization chain reaction (HCR) multiple signal amplification strategy. Firstly, Au/PPy–rGO was employed onto a bare GCE by electrodeposition that can greatly enhanced conductivity and effectively immobilize probes. Then, the thiolated capture probes (SH-CP) were self-assembled on the Au/PPy–rGO modified GCE via Au-S bond. The target miRNA triggered the dynamic assembly of the two hairpin substrates (H1 and H2), leading to the cyclicality of the target miRNA and the formation of H1–H2 complexes without the assistance of enzyme. Subsequently, the newly emerging DNA fragment of H2 triggered the HCR when a mixture solution (hairpins H3 and H4) and produced dsDNA polymers. Finally, a substantial amount of methylene blue (MB) as signal indicator was intercalated into the minor groove of the long dsDNA polymers to achieve detected electrochemical signal. The fabricated sensor is able to detect miRNA-16 (model target) with concentration range from 10 fM to 5 nM with a low detection limit (LOD) of 1.57 fM (S/N = 3). Current research suggests that the developed multiple signal amplification platform has a great potential for the applications in the field of biomedical research and clinical analysis.

Intermolecular complexes of [B6H6]2− with nH2 (n = 1-8) molecules: a theoretical study

Ab initio calculations were used to analyze the interactions among [B6H6]2− dianion with H2 molecules at the MP2/aug-cc-pVTZ computational level. The vibrational spectrum of the optimized complexes has been studied for consolidation testing. The triangular faces at the surface of the [B6H6]2− have enough potential to act as the main focus for interaction with H2 molecules. The results show that the stabilization energies of the [B6H6]2− increase with increasing H2 number. The unscaled vibrational stretching frequencies B-H and H2(H-H) show blue shifts and red shifts, respectively. The cooperativity in [B6H6]2− H2 complexes has been investigated. The Atoms in Molecules (AIM 2000) method was applied to analyze the interactions.

Complexes between H2 and neutral oxyacid beryllium derivatives. The role of angular strain

ABSTRACTThe complexes between 14 different Be-salts of oxyacids from groups 13 to 16 with one and two molecules of H2 have been investigated by means of the MP2/aug-cc-pVTZ ab initio molecular orbital theory method, which was found to be reliable for the treatment of these weakly bound species. The main conclusion is that these Be-salts yield rather stable complexes with dihydrogen, with binding energies one order of magnitude larger than other typical H2 complexes reported in the literature. This strong binding is shown to be due to an enhancement of the electron-deficient nature of Be when attached to an oxyacid moiety, which depends more on the type of coordination of the central atom of the oxyacid moiety. The formation of these complexes is followed by a significant lengthening of the H2 internuclear distance and a concomitant red-shift of the H–H stretching frequency, which becomes a good indicator of the strength of the interaction. The charge shifting from the bonding region of the H2 molecule to the interboundary Be···H2 region is the physical phenomenon behind the stability of these complexes. Accordingly, the most important contributor to this stability is the inductive term, followed by the electrostatic interactions. The ability of Be to bind H2 is enhanced by the angular arrangement of the O–Be–O electron-acceptor group.

Utilization of Thermodynamic Scaling Relationships in Hydricity To Develop Nickel Hydrogen Evolution Reaction Electrocatalysts with Weak Acids and Low Overpotentials

Two heteroleptic nickel(II) complexes of the type [Ni(bis-NHC)(dRpe)]2+ (1, R = phenyl; 2, R = methyl; bis-NHC = 1,l′:3,3′-bis(1,3-propanediyl)dibenzimidazolin-2,2′-diylidene) have been synthesized and characterized. The complexes exhibit reversible, two-electron reductions at −1.53 and −1.87 V versus Fc+/0, respectively. Through the use of thermodynamic scaling relationships, hydricities for the corresponding nickel(II) hydride complexes 1H and 2H are estimated to be 45.6 and 37.8 kcal mol–1, respectively. Experimental estimation of an upper bound for the hydricities (ΔGH–°(1H) < 50.3 kcal mol–1 and ΔGH–°(2H) < 40.6 kcal mol–1) was determined by selection of an added weak acid such that the hydrogen evolution reaction (HER) becomes exergonic vs endergonic. Further electrochemical studies establish 2 as an efficient hydrogen evolution electrocatalyst, operating at low overpotential (η = 0.4 V) and reasonable rates (TOF ∼ 1000 s–1) using phenol as the Bronsted acid source. This demonstrates the utility of ...

Axially chiral benzimidazolium based silver(I) and gold(I) bis-NHC complexes of R-BINOL scaffold: synthesis, characterization and DFT studies

The axially chiral ligand of R-BINOL scaffold was synthesized by a series of manipulations which involved different chemical reactions to obtain the desired sliver(I) and gold(I) $$\{[\hbox {L}(\hbox {L}'\hbox {-NHC})_{2}]\hbox {M}\}\hbox {Cl}$$ ( $$\hbox {L} = 3{,}3'\hbox {-dimethyl-2}{,}2'\hbox {-dimethoxy-1,1}'\hbox {-binaphthyl}, \hbox {L}' = i\hbox {-propyl-benzo}[\hbox {d}]\hbox {imidazole})$$ (M =Ag and Au) complexes. Enantiopure R-BINOL was employed as a basic unit to synthesize a benzimidazole based bis-NHC ligand 1g which was obtained through the formation of different intermediate 1(a-f) compounds. The newly synthesized bis-NHC ligand precursor (1g) and its corresponding $$\{[\hbox {L}(\hbox {L}'\hbox {-NHC})_{2}]\hbox {Ag}\}\hbox {Cl}$$ (1h) and $$\{[\hbox {L}(\hbox {L}'\hbox {-NHC})_{2}]\hbox {Au}\}\hbox {Cl}$$ (1i) complexes were characterized by different spectroscopic techniques. The geometries of the optimized structure of the complexes 1h and 1i were computed at the B3LYP/SDD, 6-31G(d) level. Low temperature fluorescence spectroscopic studies did not show any evidence for the weak metal-metal interaction in these complexes. SYNOPSIS Synthesis, characterization of $$\{[\hbox {L}(\hbox {L}'\hbox {-NHC})_{2}]\hbox {M}\}\hbox {Cl}$$ (M = Ag and Au) (1h) and (1i) type sliver(I) and gold(I) complexes are reported. Molecular structures of these benzimidazole based, axially chiral complexes of R-BINOL scaffolds were determined by the computational studies. The results of spectroscopic and analytical data as well as the computational study show that the ligand (1g) prefers to form mononuclear bis-NHC silver(I) and gold(I) complexes in the given conditions.

Chiral Oxazolidine‐Fused N‐Heterocyclic Carbene Complexes of Rhodium and Iridium and Their Utility in the Asymmetric Transfer Hydrogenation of Ketones

The catalytic potential of new N‐heterocyclic carbene ligands, derived from a chiral fused bicyclic ring scaffold with restricted rotation along the C–N bond bearing the chiral auxiliary, has been explored in the transition‐metal‐mediated asymmetric transfer hydrogenation reactions of ketones. In particular, the chiral oxazolidine‐fused N‐heterocyclic carbene precursors (3S)‐3‐R‐6‐methyl‐7‐phenyl‐2,3‐dihydroimidazo[5,1‐b]oxazol‐6‐ium iodide [R = sec‐butyl (1f), i‐butyl (2f), isopropyl (3f)] were synthesized from commercially available optically pure amino acids in a multistep sequence that avoids tedious chiral resolution. The reactions of the chiral imidazolium iodide salts 1f–3f with Ag2O yielded the corresponding silver complexes 1g–3g, which were treated with [(COD)MCl]2 (M = Rh, Ir; COD = 1,5‐cyclooctadiene) to afford the rhodium(I) and iridium(I) complexes (1h–3h and 1i–3i, respectively). The rhodium(I) and iridium(I) complexes conveniently catalyze the asymmetric transfer hydrogenation of acetophenones for a wide variety of substrates ranging from electron‐rich ones such as 4‐methylacetophenone, 3,4‐dimethylacetophenone, 4‐tert‐butylacetophenone, and 4‐(methylthio)acetophenone to electron‐deficient ones such as 4‐bromoacetophenone, 4‐chloroacetophenone, 4‐fluoroacetophenone, 4‐nitroacetophenone, and 3‐fluoroacetophenone in moderate‐to‐good yields (ca. 18–95 %) but with low enantioselectivities (ca. 4–41 % ee).

Gold(I) Hydrides as Proton Acceptors in Dihydrogen Bond Formation.

Wavefunction and DFT calculations indicate that anionic dihydride complexes of AuI form strong to moderate directed Au-H⋅⋅⋅H bonds with one or two HF, H2 O and NH3 prototype proton donor molecules. The largely electrostatic interaction is influenced by relativistic effects which, however, do not increase the binding energy. Very weak Au⋅⋅⋅H associations-exhibiting a corresponding bond path-occur between neutral AuH and HF units, although ultimately F becomes the preferred donor atom in the most stable structure. Increasing the hydridicity of AuH by attachment of an electron donating NHC ligand effects Au-H⋅⋅⋅H bonding of moderate strength only with HF, whereas competing Au⋅⋅⋅H interactions dominate for H2 O and NH3 . Rare η2 coordinated and HX (X=F or OH) associated H2 complexes are produced during interaction with a single ion of stronger acidity, H2 F+ or H3 O+ . Theoretically, reaction of excess [AuH2 ]- as proton acceptor with H3 O+ or NH4+ in 3:1 or 4:1 ionic ratios, respectively, affords H⋅⋅⋅H bonded analogues of Eigen-type adducts. Outstanding analytical relationships between selected bonding parameters support the integrity of the results.

Characterization of a Borane σ Complex of a Diiron Dithiolate: Model for an Elusive Dihydrogen Adduct.

The azadithiolate complex Fe2[(SCH2)26NMe](CO)6 reacts with borane to give an initial 1:1 adduct, which spontaneously decarbonylates to give Fe2[(SCH2)2NMeBH3](CO)5. Featuring a Fe-H-B three-center, two-electron interaction, the pentacarbonyl complex is a structural model for H2 complexes invoked in the [FeFe]-hydrogenases. The pentacarbonyl compound is a "σ complex", where a B-H σ bond serves as a ligand for iron. The structure of this σ complex was characterized by variable-temperature NMR spectroscopy and X-ray crystallography. Complementary to the 1:1 borane adduct is the quaternary ammonium complex [Fe2](SCH2)2NMe2](CO)6]+, which was also characterized. It represents a kinetically robust analogue of the N-protonated amine cofactor, as indicated by its mild reduction potential.

Interactions between metal cations with H2 in the M+- H2 complexes: Performance of DFT and DFT-D methods

The interactions between metal cations (Ni+, Cu+, Zn+) and H2 molecule have been investigated in detail using dispersion-corrected and -uncorrected double hybrid density functional (DHDF), gradient corrected density functional, ordinary density functional and CCSD(T) methods in conjunction with the correlation consistent triple- ζ quality basis sets. Structural properties, depth of the potential well and dissociation energies are calculated using DFT, DFT-D and CCSD(T) methods and are compared with experimental results. A comparative analysis has been made among DFT, DFT-D and CCSD(T) methods with respect to experiments. The energy components of the interaction energy have been estimated by the symmetry-adapted perturbation theory (SAPT) to analyze the effect of various components on the interaction of the complexes. The dispersion-corrected DHDF, mPW2PLYP-D method shows the best agreement with the experimental values. An NBO analysis has been performed to understand the orbital participation in metal ligand interaction and charge transfer process in these complexes.

A novel surface plasmon resonance biosensor for enzyme-free and highly sensitive detection of microRNA based on multi component nucleic acid enzyme (MNAzyme)-mediated catalyzed hairpin assembly

MicroRNAs (miRNAs) are potentially useful biomarkers for early diagnosis of human diseases. Here, a simple surface plasmon resonance (SPR) biosensor has been developed for highly sensitive detection of miRNA by designing a new enzyme-free and isothermal amplification strategy, named multi component nucleic acid enzyme-mediated mismatched catalyzed hairpin assembly (MNAzyme-CHA). The partial MNAzymes co-recognized the target to form a stable active MNAzyme, which continued to digest multiple hairpin H0 substrates, concomitantly generating a lot of fragments. The H0 fragments could initiate the mismatched CHA cycles, resulting in the generation of massive hairpin H1–H2 complexes. As a result, the H1–H2 complexes and streptavidin were attached to the sensor surface, leading to a significantly amplified SPR signal readout. The established biosensor showed high sensitivity and selectivity with a wide dynamic range from 1pM to 100nM. It was also successfully applied to the determination of target miRNA spiked into human total RNA samples. Thus, this developed biosensing strategy presents a simple and stable platform toward sensitive and convenient miRNA detection, and has great potential in assays of many other nucleic acids analytes for biomedical research and early clinical diagnosis.

Synthesis and cytotoxic activity of dibutyltin complexes derived from pyridoxamine and salicylaldehydes

The synthesis of monomeric pentacoordinated diorganotin complexes derived from pyridoxamine dihydrochloride and substituted salicylaldehydes is described. The complexes were characterized using UV/Vis, IR, MS, as well as 1H, 13C, and 119Sn NMR techniques; the molecular structure of the 1e complex was established by X-ray diffraction, which showed a distorted trigonal bipyramidal geometry, in which the basal plane is defined by the butyl groups and the azomethine nitrogen atom, whereas the oxygen atoms from the aromatic ring occupy axial positions. The cytotoxic activity of the complexes against human cell lines U-251 (glioblastoma), PC-3 (prostate), K-562 (chronic myelogenous leukemia), HCT-15 (human colorectal), MCF-7 (human breast), SKLU-1 (non-small cell lung), and MDA-MB-251 (human breast) was evaluated, and the inhibitory percentage values indicated higher activities than the reference standard, cis-platin, and non-cytotoxic activity was observed in culture of mononuclear cells from peripheral blood on healthy Wistar rats. Oral toxicity studies were performed by the OECD test guide line 423 and reveals that LD50 of complexes 1a, 1b, 1c–1g is in the range of 200–300 mg/Kg body weight and can be classified under category 3, the complexes 1c and 1h resulted to be the less toxic.