Monoclinic Space Group Research Articles

3-Ferrocenyl-estra-1,3,5 (10)-triene-17-one: Synthesis, Crystal Structure, Hirshfeld Surface Analysis, DFT Studies, and Its Binding to Human Serum Albumin Studied through Fluorescence Quenching and In Silico Docking Studies.

3-ferrocenyl-estra-1,3,5 (10)-triene-17-one (2), [Fe(C5H5)(C24H25O3)], crystallizes in the monoclinic space group C2. The cyclopentadienyl (Cp) rings adopt a nearly eclipsed conformation, and the Cp plane is tilted by 87.66° with respect to the substituted phenyl plane. An average Fe-C(Cp) bond length of 2.040(13) Å was determined, similar to the one reported for ferrocene. Hirshfeld surfaces and two-dimensional fingerprint plots were generated to analyze weak intermolecular C-H···π and C-H···O interactions. Density functional theory studies revealed a 1.15 kcal/mol rotational barrier for the C3-O1 single bound. Fluorescence quenching studies and in silico docking studies suggest that human serum albumin forms a complex with 2 via a static mechanism dominated by van der Waals interactions and hydrogen bonding interactions.

Praziquantel meets Niclosamide: A dual-drug Antiparasitic Cocrystal

In this paper we report a successful example of combining drugs through cocrystallization. Specifically, the novel solid is formed by two anthelminthic drugs, namely praziquantel (PZQ) and niclosamide (NCM) in a 1:3 molar ratio, and it can be obtained through a sustainable one-step mechanochemical process in the presence of micromolar amounts of methanol. The novel solid phase crystallizes in the monoclinic space group of P21/c, showing one PZQ and three NCM molecules linked through homo- and heteromolecular hydrogen bonds in the asymmetric unit, as also attested by SSNMR and FT-IR results. A plate-like habitus is evident from scanning electron microscopy analysis with a melting point of 202.89 °C, which is intermediate to those of the parent compounds. The supramolecular interactions confer favorable properties to the cocrystal, preventing NCM transformation into the insoluble monohydrate both in the solid state and in aqueous solution. Remarkably, the PZQ - NCM cocrystal exhibits higher anthelmintic activity against in vitro S. mansoni models than corresponding physical mixture of the APIs. Finally, due to in vitro promising results, in vivo preliminary tests on mice were also performed through the administration of minicapsules size M.

Three-in-One Tetrahedral Functional Units Constructing Diamondlike Ag2In2SiS3.06Se2.94 with High-Performance Nonlinear-Optical Activity.

Exploration of new functional materials with enhanced performance from known ones is always an attractive strategy. A new infrared (IR) nonlinear-optical (NLO) mixed chalcogenide Ag2In2SiS3.06Se2.94 (1), was obtained through partial congener substitution originated from Ag2In2SiS6 (0). 1 crystallizes in the monoclinic space group Cc, and its three-dimensional (3D) polyanionic network is composed of {[In4Si2Se5(S/Se)11]12-}∞ helical chains sharing S/Se(5) corner atoms with cavities embedded with counterion Ag+ ions. It exhibits a much enhanced NLO response compared to that of 0, reaching 1.1 × AgGaS2. Further theoretical analysis results indicate that the large NLO response can be attributed to the synergistic effect of AgQ4 and InQ4 tetrahedral functional motifs. This work not only reports a new high-performance IR NLO material but also enriches the partial ion substitution strategy to obtain new functional materials.

Nucleation & growth of α-Ti(HPO4)2·H2O single-crystal and its structure determination from X-ray single–crystal data

α-titanium phosphate phase [α-Ti(HPO4)2·H2O; abbreviated as α-TiP] is a nanolayered metal phosphate with several industrial and recent biotechnological applications related to their nanolayered morphology and ion exchange capabilities. Structural wise, α-TiP is a tetravalent metal phosphate that tends to crystallize into microcrystalline powder. Here we report that the crystallization of single α-TiP crystals with suitable dimensions (>50 μm) for single-crystal X-ray diffraction could be effectuated using a prolonged hydrothermal treatment of a metallic titanium alloy (Ti–6Al–4V) in a highly concentrated phosphoric acid aqueous solution. Accordingly, the single-crystal X-ray diffraction analysis revealed the crystalline structure in a monoclinic space group, P21/c, with a = 8.6288(5) Å, b = 5.00546(17) Å, c = 19.1468(11) Å, and β = 127.555(9)°. Although the space group is the same crystallographic space group that was previously reported from the microcrystalline powder relying on powder X-ray diffraction (PXRD) and neutron powder diffraction, the obtained unit cell volume is slightly larger. Bulk of the obtained crystals were also subjected to detailed analyses using polarization optical microscopy (POM), scanning electron microscopy combined with energy dispersive X-ray microanalysis (SEM-EDX), Fourier transform Infrared Spectroscopy (FTIR) and thermal analysis (TG/SDTA). The single crystals are hexagonally shaped and exhibit the exact titanium to phosphorus ratio expected for α-TiP. The bulk sample PXRD pattern resembles perfectly that reported for the α-TiP polycrystalline powder with clearly sharper peaks. TGA-SDTA analysis revealed the expected thermal behaviour for α-TiP phase and demonstrated their higher thermal stability when compared to the polycrystalline powder.

Architecture of the rings of 5-arylidenerhodanine derivatives versus P-gp inhibition.

5-Arylidene derivatives of rhodanine show various biological activities. The new crystal structures of five derivatives investigated towards ABCB1 efflux pump modulation are reported, namely, 2-[5-([1,1'-biphenyl]-4-ylmethylidene]-4-oxo-2-thioxothiazolidin-3-yl)acetic acid dimethyl sulfoxide monosolvate, C18H13NO3S2·C2H6OS (1), 4-[5-([1,1'-biphenyl]-4-ylmethylidene]-4-oxo-2-thioxothiazolidin-3-yl)butanoic acid, C20H17NO3S2 (2), 5-[4-(benzyloxy)benzylidene]-2-thioxothiazolidin-4-one, C17H13NO2S2 (3), 4-{5-[4-(benzyloxy)benzylidene]-4-oxo-2-thioxothiazolidin-3-yl}butanoic acid, C21H19NO4S2 (4), and 5-[4-(diphenylamino)benzylidene]-2-thioxothiazolidin-4-one, C22H16N2OS2 (5). Compounds 1 and 3-5 crystallize in the triclinic space group P-1, while 2 crystallizes in the monoclinic space group P21/n, where the biphenyl moiety is observed in two positions (A and B). Two molecules are present in the asymmetric unit of 5 and, for the other four compounds, there is only one molecule; moreover, 1 crystallizes with one dimethyl sulfoxide molecule. The packing of the molecules containing a carboxyl group (1, 2 and 4) is determined by O-H...O hydrogen bonds, while in the other two compounds (3 and 5), the packing is determined by N-H...O hydrogen bonds. Additionally, induced-fit docking studies have been performed for the active compounds to investigate their putative binding mode inside the human glycoprotein P (P-gp) binding pocket.

A nickel(II) complex with an unsymmetrical tetra-dentate chelating ligand derived from pyridine-2,6-dicarbaldehyde and 2-amino-thio-phenol.

[(2-{[6-(1,3-Benzo-thia-zol-2-yl)pyridin-2-yl]carbonyl-aza-nid-yl}phen-yl)sulf-anido]nickel(II), [Ni(C19H11N3OS2)], crystallizes in the centrosymmetric monoclinic space group P21/n with one mol-ecule in the asymmetric unit. The expected ligand, a bis-Schiff base derived from pyridine-2,6-dicarbaldehyde and 2-amino-thio-phenol, had modified in situ in a both unexpected and unsymmetrical fashion. One arm had cyclized to form a benzo[d]thia-zol-2-yl functionality, while the imine linkage of the second arm had oxidized to an amide group. The geometry about the central NiII atom is distorted square-planar N3S. The mol-ecules form supra-molecular face-to-face dimers via rather strong π-π stacking inter-actions, with these dimers then linked into chains via pairwise C-H⋯O inter-actions.

Structure, spectroscopic investigations and discussion on conductivity of rare-earth metal thiophosphates(V) hosting silver ions in the Ag3RE[PS4]2 series (RE = Y, Dy, Ho and Er)

As the ongoing research in cation-conductive thiophosphates attracted attention especially for the Li+-ion conducting materials, their great structural variety and potential application motivated research on other thiophosphates as well. Here we present the silver-containing yttrium thiophosphate(V) Ag3Y[PS4]2 (a = 1697.65(9), b = 924.38(5), c = 937.46(5) pm, β = 123.217(3)°, Z = 4) plus three new lanthanoid representatives, namely Ag3Dy[PS4]2, Ag3Ho[PS4]2 and Ag3Er[PS4]2, crystallizing isotypically in the monoclinic space group C2/c. These new compounds were synthesized from the respective sulfides (Ag2S, RE2S3 and P2S5; RE = Y, Dy, Ho and Er) in fused glassy silica ampoules under inert conditions at 700 °C. The crystal structure of the materials was revisited to reveal [AgS4]7–, [RES8]13− and [PS4]3– polyhedra as building blocks, and spectroscopic studies were first performed on these particular Ag3RE[PS4]2 samples. Electrochemical impedance spectroscopy (EIS) shed light on the Ag+-conducting potential of these thiophosphates for the example of Ag3Ho[PS4]2. Raman-spectroscopic investigations confirmed the presence of [AgS4]7– and discrete [PS4]3– tetrahedra and the studies of the diffuse reflectance (DRS) revealed optical band gaps of Eg = 2.4–2.7 eV.

Insight on the presence of dimethylammonium cation within anionic metal-organic supramolecular host: structural, Hirshfeld surface, optical and theoretical analysis

A new supramolecular metal-organic complex, [(DMA)+{Fe(IDA)2}-] (where H2IDA = iminodiacetic acid and DMA = dimethylammonium cation) (1), has been synthesized solvothermally at 90 °C from reaction of ferric(III) chloride hexahydrate with nitrilotriacetic acid (H3NTA) in stoichiometric ratio. The complex was characterized by single crystal X-ray diffraction (SCXRD) along with spectroscopic analyses. During the reaction process, H3NTA is degraded into IDA2- ligand. Structural analysis reveals that 1 is mononuclear and crystallizes in the monoclinic space group C2/c. Within the [Fe(IDA)2]- unit, Fe3+ shows six-coordinate distorted octahedral geometry. The [Fe(IDA)2]- units are connected by strong N1-H1···O4 hydrogen bonds to form anionic 2D supramolecular layers which are further connected by weak C-H···O hydrogen bonds to form a 3D metal-organic supramolecular host (MOSH) structure having 1D supramolecular channels along the crystallographic c-axis. DMA cations are present within the supramolecular channels through N2-H2···O2 hydrogen bonding interactions. Hirshfeld surface analysis and corresponding 2D fingerprint plots indicate that O···H interactions are the major supramolecular interactions present between MOSH and guest DMA cation. DFT calculations reveal that the HOMO and LUMO of the [Fe(IDA)2]- unit are composed of mixed metal-ligand orbitals. Both the absorption and emission spectra of the complex were studied in aqueous phase and the result was correlated with the TDDFT study.

Structural investigation, quantum chemical calculation, energy framework analysis and MIC studies of silver and cobalt complexes of 4-amino-N-(4, 6-dimethyl-2 pyrimidinyl) benzenesulfonamide in presence of secondary ligand

Silver and cobalt complexes of SMZ ligand (SMZ = 4-amino-N-(4, 6-dimethyl-2 pyrimidinyl) benzenesulfonamide) have been synthesized and characterized by elemental, FT-IR and 1H-NMR spectroscopy analysis. Due to the magnetic behaviour of the cobalt complex, it was characterized by EPR and magnetic susceptibility analysis. Single crystal X-ray diffraction (SC-XRD) study reveals the [Ag2(C12H14N4O2S)2(C6H7N), complex-1 crystallizes in orthorhombic space group Pbca, while [{Co(C12H13N4O2S)2(C5H5N)2}.(C5H5N)], complex-2 crystallizes in monoclinic space group C2/c. The SC-XRD analysis shows that silver in complex-1 is four-coordinate exhibiting distorted tetrahedral geometry, while cobalt in complex-2 is coordinated to six nitrogen’s leading to distorted octahedral geometry. Additionally, Hirshfeld surfaces and 2D fingerprint plots analysis shows that the H…H intermolecular contacts are the main contribution to the Hirshfeld surface area displaying values for complex-1 and complex-2 are 59.1% and 50% respectively (%H-H; complex 1 > Complex 2). In 3D energy frameworks analysis, complex-1, has shown the highest dispersion interaction energies than that of complex 2 [dispersion energy; -74.5 kJ mol-1 (complex-1) > -63.4 kJ mol-1 (complex-2)], Moreover, computational studies such as frontier molecular orbital (FMO), natural bond orbital (NBO) and Mulliken population analysis (MPA) were calculated using B3LYP method. Besides, The MIC data against panel of gram-positive and gram-negative organisms confirm that both the metal complexes of SMZ ligand possesses better inhibitory activities than that of SMZ ligand. The MIC data shows the silver complex exhibits comparatively better response towards the panel of the gram positive and gram negative bacteria. Furthermore, the molecular docking study agrees that the binding affinity of the complexes with 1BNA is higher than that of free SMZ ligand.

Crystal structure, Hirshfeld surface analysis, and computational study of tin (IV) complex: Insights from spectroscopic, anticancer and cytotoxic properties

The complex di(p-methylbenzyl) (dibromo)(4,7-diphenyl-1,10-phenanthroline) tin (IV) complex (B1) was synthesized and characterized. For the theoretical investigation, we used DFT. With the help of the Multiwfn software package, topological analysis and RDG were calculated. A very low energy gap (2.3 eV) was observed in the HOMO-LUMO analysis. Nucleophilic and electrophilic attacking sites are confirmed using the MEP study. In a single crystal, analysis confirmed the octahedral shape and monoclinic space group. The intramolecular hydrogen was formed through the C—H—Br. The tin atom is in a uniform octahedral shape, which can be seen in the XRD of the complex B1. The Vero and Hela cell lines are used for anticancer and cytotoxic activities. Our synthesized complex shows better activity against Vero and Hela cell lines when compared to cisplatin.

A novel centrosymmetric [C7H9NF]2ZnCl4 hybrid material: Synthesis, crystal structure, thermal, vibrational spectroscopy, optical and photoluminescence properties

A novel organic–inorganic hybrid material, [C7H9NF]2ZnCl4, was obtained by slow evaporation at room temperature and characterized by single crystal X-ray diffraction. The compound has monoclinic space group P21/n with the following cell parameters: a= 15.1956(10) Å, b= 7.2108(3) Å, c = 36.103(2) Å, β=93.16°, V=3950.1 Å3 and Z=8. The crystal structure consists of tetrahedral [ZnCl4]2− anions and 4-fluorobenzylammonuim [C7H9NF]+ cations connected by hydrogen bonding N–H…Cl, C–H…Cl, π-π, and van der Waals interactions, which ensures the stability of the crystal packing, forming layers lying approximately within the (101) planes. RT- XPRD was carried out to identify the purity of the synthesis material. Infrared spectroscopy technique is used to characterize the vibrational properties of the system. The material exhibits thermal stability up to 180 °C. Hirshfeld surface analysis reveals the significance of hydrogen bonds and electrostatic interactions in the material cohesion, while 2D fingerprint plots indicate the contributions of the H…Cl and H…H intermolecular interactions. The material also displays diffuse absorption, indicating the existence of optical direct allowed transition mechanisms with the band gap energy equal to 4.33 eV. Its photoluminescence spectrum extends over the entire visible band when excited by ultraviolet radiation. Owing to these properties, the compound is promising for use in optical devices.

Sol-gel synthesis and Opto-electrical properties study of double perovskite oxide Dy2NiMnO6 thin film

Thin film of double perovskite oxide Dy2NiMnO6 (DNMO) has been synthesised by the simple and cost-effective chemical solution deposition technique. The room temperature X-ray diffraction pattern and Raman spectroscopy confirm the monoclinic (space group - P21/n) crystal structure of polycrystalline DNMO thin film. The optical and electrical properties of DNMO thin film are investigated to study the detailed photo physical properties of DNMO thin film. The direct band gap and temperature dependant impedance spectroscopy confirm its semiconductor behaviour. Impedance spectroscopy also shows two types of dielectric relaxation behaviour and the nature of conductivity reveals the electron hopping conduction mechanism. Moreover, the chemical solution deposited DNMO film shows promising photo response under white light.

Structure and magnetism of the triangular lattice material YbBO3

YbBO3 is a member of the orthoborate family of materials which contains a triangular arrangement of Yb3+ ions. Here we study the physical properties of YbBO3 with neutron diffraction, inelastic neutron scattering, specific heat, and ac susceptibility measurements. The neutron diffraction measurements confirm that our samples of YbBO3 crystallize in the monoclinic space group (#15) which contains two crystallographically distinct Yb3+ sites decorating a slightly distorted triangular lattice. Heat capacity and ac susceptibility measurements indicate a potential transition to magnetic order at 0.4 K. In agreement with these observations, neutron diffraction measurements at 0.044 K observe magnetic Bragg peaks which can be indexed by a propagation vector of (0 0 1). Although determining a unique spin configuration corresponding to the observed magnetic Bragg peaks is not possible, model refinements indicate that the ordered moments are likely in the range of 0.4–0.9 and, notably, require moments on both Yb sites. In addition to the magnetic Bragg peaks, diffuse scattering at low Q is observed indicating that the transition does not correspond to complete long range magnetic order. The two-site picture for YbBO3 is further evidenced by the number of crystal field excitations observed by inelastic neutron scattering measurements. Together these results show that YbBO3 is a two-site triangular lattice material with signatures of long-range order as well as shorter ranged spin correlations.

Discovery of ferroelectricity in natural product androstane

Progesterone and its derivatives attracted widespread interest because of their applications in medicine, health care and birth control, which is the main active ingredient of contraceptive pills known as one of the five chemistry discoveries that changed human life. Although the research of pharmacological effects on contraceptive pill-related compounds has been around for decades, their ferroelectricity has long been overlooked. Here, we report that 4-androsten-3-one-5-ene-17-carboxylic acid, a derivative of progesterone, is an organic single-component ferroelectric, as confirmed by the polarization–electric field hysteresis loops. It crystallizes in the monoclinic space group P21 with a polar packing structure and undergoes a reversible structural phase transition at a high temperature of 489 K. Thermal analysis revealed that its ferroelectricity can persist up to 533 K, giving a wide working temperature range. As the first ferroelectric in steroid biomaterials, 4-androsten-3-one-5-ene-17-carboxylic acid shows great potential in applications for flexible devices, biomedical devices, bio-machines and so on.

Ultrahigh breakdown current density of van der Waals one dimensional PdBr2

One-dimensional (1D) van der Waals (vdW) materials offer nearly defect-free strands as channel materials in the field-effect transistor devices and probably, a better interconnect than conventional copper with higher current density and resistance to electro-migration with sustainable down-scaling. We report a theoretically predicted halide based 1D few-chain atomic thread, PdBr2, isolable from its bulk which crystallizes in a monoclinic space group C2/c. Liquid phase exfoliated nanowires with mean length (20 ± 1)μm transferred onto a SiO2/Si wafer with a maximum aspect ratio (length:width) of ≈5000 confirm the lower cleavage energy perpendicular to the chain direction. Moreover, an isolated nanowire can also sustain a current density of 200 MA/cm2, which is atleast one-order higher than typical copper interconnects. However, local transport measurement via the conducting atomic force microscopy (CAFM) tip along the cross direction of the single chain records a much lower current density due to the anisotropic electronic band structure. While 1D nature of the nanoobject can be linked with a non-trivial collective quantum behavior, vdW nature could be beneficial for possible pathways in an interconnect fabrication strategy with better control of placement in an integrated circuit.

Synthesis and Characterization of Iron Bispyridine Bisdicyanamide, Fe[C5H5N]2[N(CN)2

Fe[C5H5N]2[N(CN)2]2 (1) was synthesized from a reaction of stoichiometric amounts of NaN(CN)2 and FeCl2·4H2O in a methanol/pyridine solution. Single-crystal and powder diffraction show that 1 crystallizes in the monoclinic space group I2/m (no. 12), different from Mn[C5H5N]2[N(CN)2]2 (P21/c, no. 14) due to tilted pyridine rings, with a = 7.453(7) Å, b = 13.167(13) Å, c = 8.522(6) Å, β = 114.98(6)° and Z = 2. ATR-IR, AAS, and CHN measurements confirm the presence of dicyanamide and pyridine. Thermogravimetric analysis shows that π-stacking interactions of the pyridine rings play an important role in structural stabilization. Based on DFT-optimized structures, a chemical bonding analysis was performed using a local-orbital framework by projection from a plane-wave basis. The resulting bond orders and atomic charges are in good agreement with the expectations based on the structure analysis. SQUID magnetic susceptibility measurements show a high-spin state FeII compound with predominantly antiferromagnetic exchange interactions at lower temperatures.

Synthesis, Hirshfeld atom refinement of crystal structure, and Hirshfeld surface analysis of 5-ethoxycarbonyl-6-methyl-4-(2-(trifluoromethyl)phenyl)-3,4-dihydropyrimidin-2-(1H)-one formic acid monosolvate

We report the cyanamide-based multicomponent synthesis and crystal structure of the title compound, 5-ethoxycarbonyl-6-methyl-4-(2-(trifluoromethyl)phenyl)-3,4-dihydropyrimidin-2-(1H)-one which crystallized as a binary cocrystal with formic acid, C15H15F3N2O3·HCO2H (DHPM···FA). The molecular structure of the DHPM···FA heterosynthon was unequivocally confirmed using X-ray single crystal diffraction techniques and spectroscopic methods. X-ray diffraction analysis shows that this cocrystalline material crystallizes in the monoclinic space group P21/n, Z = 4 with the 3,4-dihydropyrimidin-2-(1H)-one ring in a twist-boat form attached to the ester and phenyl group in an s−cis/s−cis and sp−conformation, respectively. The molecular structure and crystalline packing are stabilized by intermolecular N2–H2∙∙∙O1, N1–H1∙∙∙O5, O4–H4A∙∙∙O1, C4–H4∙∙∙O5, C6–H6∙∙∙O3 and C16–H16∙∙∙O3 hydrogen bonds into a 3D supramolecular network R22(8). Furthermore, the Hirshfeld surface analysis confirms that the most important contributions for the crystal packing are the H∙∙∙O/O∙∙∙H (58.7%), C − H···C (17.8%), H∙∙∙H (30.4%) and H∙∙∙F/F∙∙∙H (18.3%) surface contacts.

Preference for a pressure-induced 3D structure after 1T-HfSe2

Extensive crystal structure prediction searches provide evidence of two 3D structures with orthorhombic (Immm) and monoclinic (C2/m) space groups as reasonable candidates for the first pressure-induced phase of 1T-HfSe2. Our candidates are compared with two recent proposals that keep the 2D nature of the ambient conditions phase and display hexagonal (P63/mmc) and monoclinic (C2/m) symmetry, although the latter has a different structure than our proposed C2/m phase. Both of these 2D-like structures are discarded based on simple thermodynamic and kinetic arguments that can be extended to explain the pressure-induced polymorphic sequence of other transition metal dichalcogenides. The computed observables of our orthorhombic phase are fully consistent with the experimental structural and Raman data observed at low and high-pressure.

Copper(II) halide salts of 5-bromo-2-aminopyridine and 3,5-dibromo-2-aminopyridine: syntheses, structures and magnetic behavior

Two 5-bromo-2-aminopyridinium quantum Heisenberg antiferromagnetic (QHAF) complexes of copper(II) have been synthesized and studied structurally and magnetically. The structures of (5-BAPH)2[CuCl4] (1) and (5-BAPH)(3,5-diBAPH)[CuBr4] (2) are reported [5-BAPH = 2-amino-5-bromopyridinium; 3,5-diBAPH = 2-amino-3,5-dibromopyridinium]. Single-crystal X-ray diffraction measurements show that 1 crystallizes in the triclinic space group Pī and 2 crystallizes in the monoclinic space group P21/c. Both products crystallize with a four-coordinate Cu(II) ion and are stabilized with extensive hydrogen bonding between the halide ions and pyridinium and amino substituents on each cation. The tetrahalidocuprate ions in 1 and 2 exist in distorted geometries between square planar and tetrahedral with mean trans angles of 139.48° and 131.85°, respectively. Halogen bonding is also observed. Magnetic susceptibility data were collected on 1 and 2. Magnetic susceptibility data of 1 exhibit moderate antiferromagnetic interactions which are best fit using an alternating chain model [CC = 0.4262(3) cm3 K mol−1, J/kB = −22.75(2) K, α = 0.134(3)]. Magnetic susceptibility data of 2 exhibit weak antiferromagnetic interactions, best fit using a uniform chain model [CC = 0.410(6), J/kB = −6.1(4) K].

Syntheses, crystal structures, optical and antibacterial properties of two organic-inorganic hybrids containing pyridinium-substituted triphenylphosphonium and tetrachlorocobaltate/copperate(II)

In this article, we present the syntheses, crystal structures, vibrational spectra, optical and antibacterial properties of two new organic-inorganic hybrids, [Py(CH2)3TPP][CoCl4]·H2O (1) and [Py(CH2)3TPP][CuCl4] (2), where [Py(CH2)3TPP]2+ was 1-(1′-pyridyl-propyl)-3-triphenyl phosphonium. Two hybrids were crystallized in the monoclinic space group P21/n. The hybrids consisted of a [Py(CH2)3TPP]2+ cation and a tetrahedral [CoCl4]2−/[CuCl4]2− anion, where the crystal structure was stabilized by C−H···Cl, O−H···Cl, and C−H···O hydrogen bonds due to the presence of a water molecule in 1, and the crystal structure of 2 was stabilized by C−H···Cl hydrogen bonds. Experimental vibrational bands (IR and Raman) have been discussed and assigned. The intermolecular energy, the energy gap between HOMO and LUMO orbitals, as well as the first hyperpolarizabilities were predicted based on DFT calculations. The low energy gaps (1.26 eV for 1 and 1.20 eV for 2) were responsible for the charge transfer interactions that eventually occur between the cation and anion. The first hyperpolarizabilities (β tot) of 1 and 2 were 82 and 237 times as high as that of the standard KDP crystal, respectively, indicating that the as-prepared hybrids were excellent materials for NLO applications. Furthermore, it was found that both salts exhibit good bactericidal activity against Escherichia coli and Staphylococcus aureus.