Azido Complexes Research Articles

Tuning The Intracellular Distribution of [3+2+1] Iridium(III) Complexes In Bacterial And Mammalian Cells By iClick Reaction With Biomolecular Carriers Functionalized With Alkynone Groups.

Three iridium(III) triazolato complexes of the general formula [Ir(triazolatoR,R')(ppy)(terpy)]PF6 with ppy=2-phenylpyridine and terpy=2,2':6',2''-terpyridine were efficiently prepared by iClick reaction of [Ir(N3)(ppy)(terpy)]PF6, with alkynes and alkynones, which allowed facile introduction of biological carriers such as biotin and cholic acid. In contrast to the precursor azido complex, which decomposed upon photoexcitation on a very short time scale, the triazolato complexes were stable in solution for up to 48 h. They emit in the spectral region around 540 nm with a quantum yield of 15-35 % in aerated acetonitrile solution and exhibit low cytotoxicity with IC50 values >50 μM for most complexes in L929 and HeLa cells, demonstrating their high suitability as luminescent probes. Cell uptake studies with confocal luminescence microscopy in prokaryotic Gram-positive S. aureus and Gram-negative E. coli bacteria as well as eukaryotic mammalian L929 and HeLa cells showed significant uptake in particular of the cholic acid conjugates iridium(III) moiety and distinct intracellular distribution modulated by the nature of the peripheral functional groups that can easily be modified by the iClick reaction.

Antibacterial activity of Au(I), Pt(II), and Ir(III) biotin conjugates prepared by the iClick reaction: influence of the metal coordination sphere on the biological activity.

A series of biotin-functionalized transition metal complexes was prepared by iClick reaction from the corresponding azido complexes with a novel alkyne-functionalized biotin derivative ([Au(triazolatoR,R')(PPh3)], [Pt(dpb)(triazolatoR,R')], [Pt(triazolatoR,R')(terpy)]PF6, and [Ir(ppy)(triazolatoR,R')(terpy)]PF6 with dpb = 1,3-di(2-pyridyl)benzene, ppy = 2-phenylpyridine, and terpy = 2,2':6',2''-terpyridine and R = C6H5, R' = biotin). The complexes were compared to reference compounds lacking the biotin moiety. The binding affinity toward avidin and streptavidin was evaluated with the HABA assay as well as isothermal titration calorimetry (ITC). All compounds exhibit the same binding stoichiometry of complex-to-avidin of 4:1, but the ITC results show that the octahedral Ir(III) compound exhibits a higher binding affinity than the square-planar Pt(II) complex. The antibacterial activity of the compounds was evaluated on a series of Gram-negative and Gram-positive bacterial strains. In particular, the neutral Au(I) and Pt(II) complexes showed significant antibacterial activity against Staphylococcus aureus and Enterococcus faecium at very low micromolar concentrations. The cytotoxicity against a range of eukaryotic cell lines was studied and revealed that the octahedral Ir(III) complex was non-toxic, while the square-planar Pt(II) and linear Au(I) complexes displayed non-selective micromolar activity.

Bridging Titanium Nitrido Complexes Containing A Linear Ti-N-Ti Core with A Two-Coordinate Nitrido Ligand.

A series of titanium μ2-nitrido complexes supported by the triamidoamine ligand Xy-N3N (Xy-N3N={(3,5-Me2C6H3)NCH2CH2}3N3-) is reported. The titanium azido complex [(Xy-N3N)TiN3] (1-N3), prepared by salt metathesis of the chloride complex [(Xy-N3N)TiCl] (1-Cl) with NaN3, reacted with lithium metal or with alkali metal naphthalenides (alkali metal M=Na, K, and Rb) in THF to give the corresponding dinuclear μ2-nitrido complexes M[(Xy-N3N)Ti=N-Ti(Xy-N3N)] (2-M; M=Li, Na, K, Rb). Single crystal X-ray diffraction studies of 2-Li, 2-Na, and 2-K revealed alkali metal dependent structures in the solid state. While 2-Li and 2-K contain a μ2-nitrido ligand with a linear Ti-N-Ti core, 2-Na includes a μ3-nitrido ligand as part of a T-shape Ti2NaN fragment with the sodium cation weekly coordinated to the nitrido nitrogen atom. When the synthesis of the nitrido complexes was carried out in the presence of excess alkali metals, decomposition of the nitrido complexes was observed affording some intractable titanium species along with the trialkali metal salts [M3(Xy-N3N)] (3-M) (M=Li, Na, K, and Rb). These salts were also prepared by deprotonation of (Xy-N3N)H3 with the corresponding alkali metal hexamethyldisilazide and characterized by multinuclear NMR spectroscopy as well as single crystal X-ray diffraction.

Structures, electrical properties and catecholase-like activity of a series of new copper(II) coordination polymers supported by azido bridges

A series of new copper(II)-azido complexes of 1D polymeric chains of [Cu(L1)(μ1,3-N3)]n (1) and [Cu(L2)(μ1,3-N3)]n (2), and binuclear [Cu(L3)(μ1,1-N3)]2 (3) [HL1 = N-butyl-N-(5-bromosalcylidine)ethane-1,2-diamine, HL2 = N-butyl-N-(5-chlorosalcylidine)ethane-1,2-diamine, HL3 = N-butyl-N-(salcylidine)ethane-1,2-diamine] have been synthesized and characterized. Characterizations of 1–3 have been accomplished by usual physico-chemical techniques such as elemental analysis, FTIR, UV–vis and single crystal X-ray diffraction studies. X-ray diffraction analyses of 1 and 2 reveal that the monomeric units of 1D polymers are interconnected via the μ1,3-azido bridging. The coordination geometry around the copper(II) centers in 1 and 2 can be best described as distorted square pyramidal environments. Complex 3 shows a centrosymmetric structure with two copper(II) centers that are held together by μ1,1-azido bridging in a distorted square pyramidal environment. In the electrical studies of 1–3, both direct current (dc) and alternating current (ac) analyses have been carried out based on the metal-complex (1/2/3)-metal (M-S-M) structures. The sheet resistance of the deposited films and the metal-complex contact resistance are estimated by employing transfer length method (TLM) measurements. The dark current-voltage characteristics of Al-complex (1/2/3)-Al structures are analyzed by considering dual back-to-back Schottky barrier diode structure. The voltage variations of the device current under illumination (400–700 nm) clearly demonstrate the photo-sensitivity of these materials. The catalytic activities of 1–3 have been investigated towards aerial oxidation of 3,5-di-tert-butylcatechol. All three complexes exhibit potential catalytic effectiveness towards oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butyl-o-quinone (3,5-DTBQ) with turnover numbers 14.76, 33.92 and 81.02 h−1 for 1, 2 and 3, respectively.

Ligand-Dominated Activation of CO2 and CS2 by the Putative Nickel Phosphiniminato Intermediates.

Room-temperature photoactivation of the first- and second-generation PN3P-pincer nickel azido complexes 1a and 1b in the presence of CO2 or CS2 afforded N-bound carbamates, dithiocarbamates, and isothiocyanates, providing insights into CO2 and CS2 activation and demonstrating how a seemingly small difference in the ligand structure significantly influences the reactivity. Theoretical calculations disclosed that the charge of the phosphorus atom plays a critical role in determining the nitrogen atom transfer to form a plausible nickel phosphiniminato intermediate.

Photophysical investigation of highly phosphorescent N^C^N platinum(II) azido complexes and their triazole derivatives

Substitution of chloride by azide in cyclometalated 5-R-1,3-di(2-pyridyl)-benzene platinum(II) complexes (R = mesityl, methyl or 2-thienyl) leads to novel azido complexes with an intense phosphorescence that is modulated by the nature of R. An increase of the concentration brings about to the formation of aggregates with a red-shifted emission. Furthermore, the presence of the ancillary azido group allows, via i-click reaction, the obtainment of even more emissive 1,2,3-triazole derivatives. The 1,2,3-triazolate of the mesityl and 2-thienyl N^C^N–Pt(II) complexes were characterized by X-ray diffraction analysis and their photophysical properties were deeply investigated.

Jellyfish-type Dinuclear Hafnium Azido Complexes: Synthesis and Reactivity.

Di- and multinuclear hafnium complexes bridged by ligands have been rarely reported. In this article, a novel 3,5-disubstituted pyrazolate-bridged ligand LH5 with two [N2 N]2- -type chelating side arms was designed and synthesized, which supported a series of dinuclear hafnium complexes. Dinuclear hafnium azides [LHf2 (μ-1,1-N3 )2 (N3 )2 ][Na(THF)4 ] 3 and [LHf2 (μ-1,1-N3 )2 (N3 )2 ][Na(2,2,2-Kryptofix)] 4 were further synthesized and structurally characterized, featuring two sets of terminal and bridging azido ligands like jellyfishes. The reactivity of 3 under reduction conditions was conducted, leading to a formation of a tetranuclear hafnium imido complex [L1 Hf2 (μ1 -NH)(N3 ){μ2 -K}]2 5. DFT calculations revealed that the mixed imido azide 5 was generated via an intramolecular C-H insertion from a putative dinuclear HfIV -nitridyl intermediate.

Isostructural Series of Ni(II), Pd(II), Pt(II), and Au(III) Azido Complexes with a N^C^N Pincer Ligand to Elucidate Trends in the iClick Reaction Kinetics and Structural Parameters of the Triazolato Products.

An isoelectronic and isostructural series of cyclometalated azido complexes [M(N3)(dpb)] with M = Ni(II), Pd(II), Pt(II), and Au(III) based on the N^C^N pincer ligand 1,3-di(2-pyridyl)phenide (dpb) was characterized by X-ray diffraction analysis and investigated for reactivity in the iClick reaction with a wide range of internal and terminal alkynes by using 1H and 19F NMR spectroscopy. Reaction rate constants were found to increase with greater charge density in the order Ni(II) > Pd(II) > Pt(II) > Au(III). Terminal alkynes R-C≡C-R' with strongly electron-withdrawing groups R and R' exhibited faster kinetics than those with electron-donating substituents in the order CF3 > ketone > ester > H > phenyl ≫ amide, while R = CH3 resulted in complete loss of reactivity. Four symmetrical triazolato complexes [M(triazolatoCOOCH3,COOCH3)(dpb)] with M = Ni(II), Pd(II), Pt(II), and Au(III) as well as four nonsymmetrically substituted triazolato complexes [Pt(triazolatoR,R')(dpb)] originating from terminal and internal alkynes were shown by X-ray crystal structure analysis to exclusively feature N2-coordination of the five-membered ring ligand. However, the Pt(II) triazolato complexes exist as a mixture of N1- and N2-coordinated species in solution. Torsion angles between the mean planes of the N^C^N pincer and the triazolato ligand increase from a nearly coplanar to a perpendicular arrangement when going from Au(III)/Pt(II)/Pd(II) to Ni(II), while different substituents R and R' on the alkyne have no influence on the torsion angle and were rationalized by DFT calculations. Finally, a carbohydrate derivative obtained by glucuronic acid conjugation to methyl propiolate demonstrates the facile biofunctionalization of metal complexes via the iClick reaction.

A New Zn(II) Azido Complex of L-Arginine: X-ray Crystal Structure, Hirshfeld, and AIM Studies

The synthesis and X-ray crystal structure analyses of the azido complex [Zn(N3)(Arg)2](N3)·3H2O, where Arg is L-arginine, were presented. The molecular structure of the complex was further studied using FT-IR spectra as well as atoms in molecules (AIM) theory. An analysis of the crystal data indicated monoclinic crystal system and P21 space group with a = 13.0283(5) Å, b = 15.2032(7) Å, c = 13.3633(6) Å, β = 114.3580(10)°, V = 2411.28(18) Å3, and Z = 4. Two of the [Zn(N3)(Arg)2](N3)·3H2O formulae represent the asymmetric unit of this complex where the geometric parameters of both units are slightly different. In [Zn(N3)(Arg)2](N3)·3H2O, the central Zn(II) ion is penta-coordinated with two Arg molecules as a bidentate ligand and one terminally coordinated azide ion. Each of the two Arg molecules are located trans to one another and coordinated with the Zn(II) via the N and O atoms of the amino and carboxylate groups, respectively. Hence, Zn(II) is five-coordinated and has a distorted square pyramidal coordination geometry. The supramolecular structure of the [Zn(N3)(Arg)2](N3)·3H2O complex was inspected using the Hirshfeld analysis. The O···H (26.6–28.4%), H···H (32.3–35.3%), and N···H (30.4–34.0%) contacts are the most significant interactions in the crystal structure of the [Zn(N3)(Arg)2](N3)·3H2O complex. The Zn–N, and Zn–O bonds have slight covalent interactions based on the AIM study.

Synthesis of aryl‐functionalized, 1,5‐disubstituted 1,2,3‐triazoles and derivatives by arylation of zwitterionic ruthenium triazolato complexes

AbstractThe synthesis of a series of ruthenium 1,5‐disubstituted 1,2,3‐triazolato complexes, 1,5‐disubstituted 1,2,3‐triazoles, and a triazolium salt is reported. Treatment of the ruthenium azido complex [Ru]‐N3 (1, [Ru] = (η5‐C5H5)(dppe)Ru, dppe = Ph2PCH2CH2PPh2) with an excess of ethyl propiolate results in the formation of a mixture of the Z‐ and E‐forms of zwitterionic N(1)‐bound N(3)‐ethyl acryl‐4‐carboxylate triazolato complexes [Ru]N3(CH=CHCO2Et)C2H(CO2) (Z‐2) and (E‐2). The arylation of 2 with aromatic bromides gives a series of cationic N(1)‐bound N(3)‐ethyl acryl‐4‐alkoxycarbonyl triazolato complexes {[Ru]N3(CH=CHCO2Et)C2H(CO2CH2R)}[Br] (3a, R = Ph; 3b, R = C6F5; 3c, R = 4‐C6H4CN, 3d, R = 2,6‐C6H3F2) and the subsequent cleavage of the Ru‐N bond of 3a–d gives 1,5‐disubstituted 1,2,3‐triazoles N3(CH=CHCO2Et)C2H(CO2CH2R) (4a, R = Ph; 4b, R = C6F5; 4c, R = 4‐C6H4CN; 4d, R = 2,6‐C6H3F2) and [Ru]‐Br. A 1,2,3‐triazolium salt [N3(CH=CHCO2Et)(CH2C6F5)C2H2][Br] (5) was formed by transformation of 4b in BrCH2C6F5/chloroform mixture. The structures of Z‐3a and Z‐5 were confirmed by single‐crystal x‐ray diffraction analysis and both complexes participate in non‐covalent aromatic interactions in the solid‐state structures which can be favorable in the binding of DNA/biomolecular targets and have shown great potential in the application of biologically active anticancer drugs.

Synthesis, Supramolecular Structural Investigations of Co(II) and Cu(II) Azido Complexes with Pyridine-Type Ligands

Two new Co(II) and Cu(II) azido complexes with 4-picoline (4-Pic) and pyridine-2-carboxaldoxime (HAld) were synthesized by self-assembly of the organic ligand and the M(II) nitrate in the presence of azide as a co-ligand. Their structures were determined to be [Co(4-Pic)4(H2O)(N3)]NO3*H2O*4-Pic (1) and [Cu(HAld)(Ald)(N3)] (2) using X-ray single crystal diffraction. In complex 1, the coordination geometry is a slightly distorted octahedron with a water molecule and azide ion located trans to one another. On the other hand, complex 2 has a distorted square pyramid CuN5 coordination sphere with N-atoms of the organic ligand as a basal plane and azide ion as apical. All types of intermolecular contacts and their contributions in the molecular packing were analyzed using Hirshfeld analysis. The intermolecular contacts, H…H (53.9%), O…H (14.1%), N…H (11.0%) and H…C (18.8%) in 1, and H…H (27.4%), N…H (27.7%), O…H (14.7%) and H…C (13.6%) in 2 have the largest contributions. Of all the contacts, the O…H, N…H and C…C interactions in 2 and the O…H, N…H and H…C in 1 are apparently shorter than the van der Waals radii sum of the interacting atoms. Atoms in molecules (AIM) topological parameters explained the lower symmetry of the coordinated azide in 1 than 2.

Electrospray Mass Spectrometry to Study Combinatorial iClick Reactions and Multiplexed Kinetics of [Ru(N3)(N∧N)(terpy)]PF6 with Alkynes of Different Steric and Electronic Demand.

In a combinatorial approach, a family of ruthenium(II) azido complexes [Ru(N3)(N∧N)(terpy)]PF6 with terpy = 2,2':6',2″-terpyridine and N∧N as a bidentate chelator derived from 2,2'-biypridine and its 4,4'-disubstituted derivatives, 2,2'-bipyrimidine, and 1,10-phenanthroline were reacted with different internal and terminal alkynes to give access to a total of 7 × 7 = 49 triazolato complexes in a room-temperature catalyst-free iClick reaction. The reactants were mixed in a repurposed high-performance liquid chromatography (HPLC) autosampler, and the reaction progress was monitored by direct injection into an electrospray mass spectrometer. The ratio of the peak intensities of [Ru(N3)(N∧N)(terpy)]+ and [Ru(triazolato)(N∧N)(terpy)]+ was converted to a colored heat map for facile visual inspection of the conversion ratio. By automated multiple injections of the reaction mixture in fixed time intervals and plotting peak intensities over reaction time, pseudo-first-order rate constants were easily determined. Finally, nonoverlapping isotope patterns of the azido starting materials and triazolato products enabled multiplexed parallel determination of rate constants for four different ruthenium(II) azido complexes from a single sample vial, thereby reducing experiment time by 75%.

Synthesis and X-ray Structure Combined with Hirshfeld and AIM Studies on a New Trinuclear Zn(II)-Azido Complex with s-Triazine Pincer Ligand

The trinuclear [Zn3(PMT)2(Cl4)(N3)2] complex of the N-pincer ligand, 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (PMT), was obtained by self-assembly of the polydentate ligand (PMT) with ZnCl2 in the presence of azide ion as an auxiliary bridging ligand. The X-ray structure analysis revealed a monoclinic crystal system and centrosymmetric space group C2/c. There are two crystallographically independent Zn(II) sites where the Zn1 and Zn2 are tetra- and penta-coordinated with ZnN2Cl2 and ZnN4Cl coordination environments, respectively. The distortion τ4 and τ5 parameters for the Zn1 and Zn2 sites are 0.93 and 0.52, respectively. Hence, the Zn(1)N2Cl2 has a distorted tetrahedral configuration, while the Zn(2)N4Cl coordination sphere is intermediate between the square pyramidal and trigonal bipyramidal configurations. In this complex, the PMT is a tridentate N-chelate, while the chloride and azide anions are terminal and μ(1,1) bridged ligands, respectively. The %H…H, N…H, Cl…H, and C…H are 40.8, 17.2, 16.0, and 10.1%, respectively, based on Hirshfeld analysis. The charges at the Zn1 (+0.996 e) and Zn2 (+1.067 e) sites are calculated to be less than the official charge of the isolated Zn(II) ion. The μ(1,1) bridged azide has two asymmetric N–N bonds with clear covalent characters. In contrast, the Zn–N and Zn–Cl bonds have predominant closed-shell characters.

Synthesis, Molecular and Supramolecular Structures of Symmetric Dinuclear Cd(II) Azido Complex with bis-Pyrazolyl s-Triazine Pincer Ligand

A new dinuclear Cd(II)-azido complex of 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (PMT) pincer ligand is synthesized. Its single crystal X-ray structure reveals the dinuclear [Cd(PMT)(Cl)(N3)]2 formula. The triclinic crystal parameters are a = 9.323(4) Å, b = 10.936(5) Å, c = 11.312(6) Å, α = 112.637(10)°, β = 104.547(11)° and γ = 105.133(10)° while V = 944.1(8) Å3. Due to symmetry considerations, the asymmetric unit comprises a half [Cd(PMT)(Cl)(N3)]2 formula. The Cd(II) is hexa-coordinated with one tridentate PMT ligand in a pincer fashion mode in addition to one terminal chloride and two azide ions bridging the two Cd(II) centers in double μ(1,1) bridging mode. Unusually, the Cd-N(s-triazine) bond is not the shortest among the Cd-N interactions with the PMT pincer ligand. The supramolecular structure of the dinuclear [Cd(PMT)(Cl)(N3)]2 formula is controlled by a significant amount of Cl…H (16.4%), N…H (25.3%), H…C (9.8%) and H…H (37.2%) interactions based on Hirshfeld surface analysis. Careful inspection of the shape index map reveals the presence of some weak π-π stacking interactions between the s-triazine and pyrazolyl moieties. The percentage of C…C contacts is 1.9% where the C2…C8 (3.462 Å) is the shortest while the centroid–centroid distance is 3.686 Å. Natural charge analysis describes the charge transferences from the ligand groups to the Cd(II), while and atoms in molecules (AIM) give an indication on the properties of the Cd-N and Cd-Cl bonds.

Reactivity of the TpRu(HN=CPh2)(PPh3)−Azido complex and Insertion of Methylene into the Tp B−H Bond

• We report [3+2] cycloaddition reactions of alkyne with the ruthenium azido complex. • The stable triazolato and tetrazolato products obtained in all cases were N (2)-bound. • We report that during protonation of ruthenium azido complex, methylene insertion accidentally took place, to yield unusual boron-methylated product. • Their structures are elucidated by IR, NMR and X-ray crystallography. Herein, we report on the reactivity of an Ru(II) azido complex allowing the facile synthesis of further interesting complexes. Starting from the parent chlorido complex (HN=CPh 2 )[Ru]−Cl { 1 , [Ru] = Tp(PPh 3 )Ru; Tp = HB(pz) 3 , pz = pyrazolyl)} the title complex (HN=CPh 2 )[Ru]−N 3 ( 2 ) was obtained upon reaction with NaN 3 . The N (2)-bound 4,5-bis-(methoxycarbonyl)-1,2,3-triazolato complex (HN=CPh 2 )[Ru]−{N 3 C 2 (CO 2 Me) 2 } ( 3 ) was obtained from reaction of 2 with dimethyl acetylene dicarboxylate (DMAD). Protonation of 3 with HCl afforded the N -coordinated triazolato complex {HN 3 C 2 (CO 2 Me) 2 }[Ru]−Cl ( 4 ). Reaction of CS 2 with 2 produced the thiocyanato complex (HN=CPh 2 )[Ru]−NCS ( 5 ). The Ru tetrazolato complex (HN=CPh 2 )[Ru]−N 4 C[C(CN)=C(CN) 2 ] ( 6 ) was prepared from 2 and tetracyanoethylene (TCNE). The reaction of 2 with HX gave the 17-electron Ru(III) complexes (Cl)[Ru]−X ( 7a , X = Cl ; 7b , X = Br) and the Ru(II) complexes containing the methyl tris(pyrazolyl)borate ligand Me Tp(PPh 3 )(HN=CPh 2 )Ru−X ( 8a , X = Cl ; 8b , X = Br), as a result of an unusual methylene insertion into the B−H bond of the Tp ligand with the CH 2 Cl 2 solvent as the assumed source for the methylene. The structures of 4, 5, 7a, 7b and 8b had been determined by X-ray diffraction analysis.

Synthesis and molecular structure of arene ruthenium(II) complexes containing benzhydrazone derivative ligands with antibacterial and antioxidant properties

A suitable method for the synthesis of ruthenium(II) arene benzhydrazone complexes (1–6) of the general formula [(η6-arene)Ru(L)Cl] (arene = p-cymene or benzene; L= bidentate substituted benzhydrazone derivatives) has been described. The composition of all the complexes have been established by IR, UV-Vis and NMR spectroscopies and ESI-MS. Ruthenium precursors [(η6-arene)RuCl2]2 (arene = p-cymene or benzene) on reacting with benzhydrazone derivative ligands (L1, L2 and L3) resulted in the formation of mononuclear neutral complexes (1-6). All the neutral complexes were further reacted with NaN3 to yield azido complexes (7-12). Then, the binding modes of the benzhydrazone derivatives to the metal center for complexes (1, 5, 6, 7 and 9) have been confirmed by single-crystal X-ray diffraction studies. Further, their in-vitro antibacterial activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli, Klebsiella pneumoniae) strains have been evaluated for the complexes (1-6) and their ligands. An anti-bacterial study revealed that complex 1 and complex 6 have magnificent activity against S. aureus, E. coli and K. pneumoniae. For antioxidant properties, all the complexes showed a higher percentage of DPPH radical scavenging activity than the ligands.

Mononuclear cobalt(III) azido complex containing a tetradentate amine: one pot synthesis, structure and thermal behavior

One hexacoordinated mononuclear complex trans-[Co(L)(N3)2] PF6 (1) [L = N,N′-bis(3-aminopropyl)- 1,2-ethanediamine] is prepared by using one-pot reactions of the building units and characterized. X-ray analysis shows that cobalt center in 1 adopts a distorted octahedral geometry with CoN6 chromophore ligated through four N atoms of tetradentate amine (L) and the two N atoms of terminal azides in mutual trans orientation. In the crystalline state, double N-H…N and multiple N-H…F hydrogen bondings result in 2D sheet structure. The compound has a thermal stability up to 193°C.
 Bangladesh J. Sci. Ind. Res. 57(2), 109-116, 2022

The straightforward synthesis of N-coordinated ruthenium 4-aryl-1,2,3-triazolato complexes by [3 + 2] cycloaddition reactions of a ruthenium azido complex with terminal phenylacetylenes and non-covalent aromatic interactions in structures.

The straightforward preparation of N-coordinated ruthenium triazolato complexes by [3 + 2] cycloaddition reactions of a ruthenium azido complex [Ru]–N3 (1, [Ru] = (η5-C5H5)(dppe)Ru, dppe = Ph2PCH2CH2PPh2) with a series of terminal phenylacetylenes is reported. The reaction products, N(2)-bound ruthenium 4-aryl-1,2,3-triazolato complexes such as [Ru]N3C2H(4-C6H4CN) (2), [Ru]N3C2H(4-C6H4CHO) (3), [Ru]N3C2H(4-C6H4F) (4), [Ru]N3C2H(Ph) (5) and [Ru]N3C2H(4-C6H4CH3) (6) were produced from 4-ethynylbenzonitrile, 4-ethynylbenzaldehyde, 1-ethynyl-4-fluorobenzene, phenylacetylene and 4-ethynyltoluene, respectively, at 80 °C or above under an atmosphere of air. To the best of our knowledge, this is the first example of the preparation of N-coordinated ruthenium aryl-substituted 1,2,3-triazolato complexes by the [3 + 2] cycloaddition of a metal-coordinated azido ligand and a terminal aryl acetylene, less electron-deficient terminal aryl alkynes. All of the compounds have been fully characterized and the structures of complexes 2, 3, 5 and 6 were confirmed by single-crystal X-ray diffraction analysis. Each compound participates in non-covalent aromatic interactions in the solid-state structure which can be favorable in the binding of DNA/biomolecular targets and has shown great potential in the development of biologically active anticancer drugs.

Pharmacological applications of azido complexes derived from N-(2’-hydroxyacetophenone)-L-alanate

Assistant Professor, PG and Research Department of Chemistry, D.K.M College for Women (Autonomous), Vellore-632001

Ligand mediated structural diversity of copper(II)-azido moiety: Synthesis, structure and magnetic study

Two copper azido complexes [Cu4(L1)4(µ1,1-N3)3(N3)] (1) and [{Cu2(L2)(N-benzylen)(µ1,1-N3)3(µ1,1,3-N3(N3)]n (2) have been synthesized by the reaction of aqueous solution of sodium azide to a methanolic solution of copper perchlorate hexahydrate and corresponding Schiff-base ligands. Schiff bases HL1 and HL2 act as blocking coligands are derived from the 1:1 condensation of N-benzyl ethylenediamine with Salicyldehyde and 2-hydroxy-5-chloroacetophenone respectively (N-benzylen is the N-benzyl ethylenediamine). These two complexes are characterized by the elemental analysis, FT-IR, single crystal X-ray diffraction, powder XRD and also TGA. Single crystal X-ray structural study reveals that complex 1 is the only single μ1,1- azido bridged chain tetramer to the best of our knowledge and complex 2 is a mixed ligand azido bridged one dimensional chain which also represents the unique example containing three types of azido bonding modes µ1,1-N3, µ1,1,3-N3 and terminal N3 present simultaneously. Magnetic susceptibility measurements between 4.5 K and 300 K showed that complex 1 and complex 2 are antiferromagnetic and ferromagnetic in nature, respectively.