Chromium(III), manganese(II) and iron(III) complexes based on hydrazone Schiff-base and azide ligands: synthesis, crystal structure and antimicrobial activity

<p>A tridentate NNO donor hydrazine Schiff base, HL, was obtained from condensation of pyridine 2-carbaldehyde and 4-hydroxy benzohydrazide. HL and azide ligands with Cr(III), Mn(II) and Fe(III) have been used to synthesize [Cr(L)(N₃)(OCH₃)]₂ (<b>1</b>), [Mn(HL)₂(N₃)₂] (<b>2</b>), and [Fe(L)(N₃)(OCH₃)]₂·H₂O (<b>3</b>). HL is quite diverse in its chelating ability and can be a neutral or monoanionic ligand as a tridentate unit. In this paper, we report structures showing different denticities of the ligand having different charges. The ligand <b>1</b>–<b>3</b> was characterized by elemental analysis, FT-IR, and UV–vis spectral studies and solid-state structures were determined by single-crystal X-ray diffraction analysis, revealing that <b>1</b> and <b>3</b> are binuclear, while <b>2</b> is mononuclear. The efficiencies of the ligand and the three complexes were evaluated for antimicrobial activity; MIC data revealed that HL <b>1</b>–<b>3</b> are not strongly active in comparison to standard drugs.</p

A Series of M^IICu^II₃ Stars (M = Mn, Ni, Cu, Zn) Exhibiting Unusual Magnetic Properties

The work in this report describes the syntheses, electrospray ionization mass spectromtery, structures, and experimental and density functional theoretical (DFT) magnetic properties of four tetrametallic stars of composition [M^II(Cu^IIL)₃]­(ClO₄)₂ (<b>1</b>, M = Mn; <b>2</b>, M = Ni; <b>3</b>, M = Cu; <b>4</b>, M = Zn) derived from a single-compartment Schiff base ligand, <i>N</i>,<i>N</i>′-bis­(salicylidene)-1,4-butanediamine (H₂L), which is the [2 + 1] condensation product of salicylaldehyde and 1,4-diaminobutane. The central metal ion (Mn^II, Ni^II, Cu^II, or Zn^II) is linked with two μ₂-phenoxo bridges of each of the three [Cu^IIL] moieties, and thus the central metal ion is encapsulated in between three [Cu^IIL] units. The title compounds are rare or sole examples of stars having these metal-ion combinations. In the cases of <b>1</b>, <b>3</b>, and <b>4</b>, the four metal ions form a centered isosceles triangle, while the four metal ions in <b>2</b> form a centered equilateral triangle. Both the variable-temperature magnetic susceptibility and variable-field magnetization (at 2–10 K) of <b>1</b>–<b>3</b> have been measured and simulated contemporaneously. While the Mn^IICu^II₃ compound <b>1</b> exhibits ferromagnetic interaction with <i>J</i> = 1.02 cm^–1, the Ni^IICu^II₃ compound <b>2</b> and Cu^IICu^II₃ compound <b>3</b> exhibit antiferromagnetic interaction with <i>J</i> = −3.53 and −35.5 cm^–1, respectively. Variable-temperature magnetic susceptibility data of the Zn^IICu^II₃ compound <b>4</b> indicate very weak antiferromagnetic interaction of −1.4 cm^–1, as expected. On the basis of known correlations, the magnetic properties of <b>1</b>–<b>3</b> are unusual; it seems that ferromagnetic interaction in <b>1</b> and weak/moderate antiferromagnetic interaction in <b>2</b> and <b>3</b> are possibly related to the distorted coordination environment of the peripheral copper­(II) centers (intermediate between square-planar and tetrahedral). DFT calculations have been done to elucidate the magnetic properties. The DFT-computed <i>J</i> values are quantitatively (for <b>1</b>) or qualitatively (for <b>2</b> and <b>3</b>) matched well with the experimental values. Spin densities and magnetic orbitals (natural bond orbitals) correspond well with the trend of observed/computed magnetic exchange interactions

Mn(III) and Cu(II) complexes of 1-((3-(dimethylamino)propylimino)methyl) naphthalen-2-ol): Synthesis, characterization, catecholase and phenoxazinone synthase activity and DFT-TDDFT study

<p>Two new complexes, [MnL₂](ClO₄) (<b>1</b>) and [CuL₂] (<b>2</b>) (where LH = (E)-1-((3-(dimethylamino)propylimino)methyl)naphthalen-2-ol), have been synthesized and characterized by spectroscopic techniques and their molecular structures are established by single-crystal X-ray diffraction study. Complex <b>1</b> adopts an octahedral geometry around the central manganese atom which is in + 3 oxidation state, whereas in complex <b>2</b>, the Cu⁺² ion preferred a square pyramidal environment around it through the ligand donor atoms. Both complexes were tested for catecholase and phenoxazinone synthase activity. Complex <b>1</b> catalyzes the oxidation of 3,5-ditertiary-butyl catechol with a <i>k</i>_cat value of 6.8424 × 10² h⁻¹ in acetonitrile whereas the same for complex <b>2</b> is 3.7485 × 10² h⁻¹ in methanol. Phenoxazinone synthase activity was shown only by complex <b>2</b> having <i>k</i>_cat = 74.225 h⁻¹. Structures of both the title complexes have been optimized by means of DFT calculations. Experimental electronic spectra of the complexes have been corroborated by TDDFT analysis. Electrochemical investigations by means of cyclic voltammetry have been carried out to study the electron transfer processes in the complexes.</p

Tetrabromoterepthalic Acid in Designing Co-crystals and Salts: Modification of Optical Properties and Schottky Barrier Effect

Herein, tetrabromoterepthalic acid (TBTA) is used as the potential co-crystal former with various organic base molecules containing free nitrogen atoms. The crystal structure of TBTA (compound <b>1</b>) has been determined from powder X-ray diffraction (PXRD) data. In a systematic way, we have synthesized hydrated-TBTA (compound <b>2</b>), two salts of TBTA [TBTA^2––4,4′-bipy²⁺ (compound <b>3</b>), 4,4′-bipy = 4,4′-bipyridine, and TBTA^2––(3-AP⁺)₂ (compound <b>4</b>), 3-AP = 3-aminopyridine] and two co-crystals of TBTA [TBTA–DPTZ (compound <b>5</b>), DPTZ = 3,6-di­(pyridyl-2-yl)-1,2,4,5-tetrazine, and TBTA–(3-IP)₂ (compound <b>6</b>), 3-IP = 3-iodopyridine]. All of the compounds were characterized by structural, spectral, and thermal studies. Supramolecular structural analysis reveals that <b>1</b> forms a 2D supramolecular sheet structure by means of O–H···Br hydrogen bonding interactions and hydrated-<b>2</b> forms a 3D supramolecular structure through water mediated hydrogen bonding interactions and π··· interactions. The O–H···N/O¯···H–N⁺ hydrogen bonding interactions between acid and base molecules give rise to 1D supramolecular chain structure in <b>3</b> and supramolecular trimers in <b>4</b>, <b>5</b>, and <b>6</b>. Because of presence of charge assisted O^¯···H–N⁺ hydrogen bonds between acid–base molecules, <b>3</b> and <b>4</b> form hydrogen bonds with solvent water molecules, and also both <b>3</b> and <b>4</b> form 3D supramolecular structures using both hydrogen bonding and π··· interactions. In co-crystal <b>5</b>, solvent water molecules participate in crystallization in contrast to <b>6</b>, and it has been observed that <b>5</b> forms 3D supramolecular structure, while <b>6</b> forms 2D supramolecular structure using both hydrogen bonding and π··· interactions. An investigation of intermolecular closed contacts has been carried out by Hirshfeld surface analysis, and associated 2D fingerprint plots reveal the similarities and differences of TBTA molecules in these six crystal structures. Photoluminescence spectra of all the compounds have been studied, and they reveal that with change of polarity around TBTA luminescent intensity of the compounds has been modified. <i>I</i>–<i>V</i> measurement indicates that <b>3</b> shows semiconducting behavior, and the ITO/<b>3</b>/Al sandwich structure acts as a Schottky barrier diode. The device exhibits an excellent rectification ratio (19 at ±1 V) with an ideality factor of 2.96. The semiconducting behavior of <b>3</b> is attributed to the formation charge assisted hydrogen bonding interactions between acid and base molecules

Tetrabromoterepthalic Acid in Designing Co-crystals and Salts: Modification of Optical Properties and Schottky Barrier Effect

Herein, tetrabromoterepthalic acid (TBTA) is used as the potential co-crystal former with various organic base molecules containing free nitrogen atoms. The crystal structure of TBTA (compound <b>1</b>) has been determined from powder X-ray diffraction (PXRD) data. In a systematic way, we have synthesized hydrated-TBTA (compound <b>2</b>), two salts of TBTA [TBTA^2––4,4′-bipy²⁺ (compound <b>3</b>), 4,4′-bipy = 4,4′-bipyridine, and TBTA^2––(3-AP⁺)₂ (compound <b>4</b>), 3-AP = 3-aminopyridine] and two co-crystals of TBTA [TBTA–DPTZ (compound <b>5</b>), DPTZ = 3,6-di­(pyridyl-2-yl)-1,2,4,5-tetrazine, and TBTA–(3-IP)₂ (compound <b>6</b>), 3-IP = 3-iodopyridine]. All of the compounds were characterized by structural, spectral, and thermal studies. Supramolecular structural analysis reveals that <b>1</b> forms a 2D supramolecular sheet structure by means of O–H···Br hydrogen bonding interactions and hydrated-<b>2</b> forms a 3D supramolecular structure through water mediated hydrogen bonding interactions and π··· interactions. The O–H···N/O¯···H–N⁺ hydrogen bonding interactions between acid and base molecules give rise to 1D supramolecular chain structure in <b>3</b> and supramolecular trimers in <b>4</b>, <b>5</b>, and <b>6</b>. Because of presence of charge assisted O^¯···H–N⁺ hydrogen bonds between acid–base molecules, <b>3</b> and <b>4</b> form hydrogen bonds with solvent water molecules, and also both <b>3</b> and <b>4</b> form 3D supramolecular structures using both hydrogen bonding and π··· interactions. In co-crystal <b>5</b>, solvent water molecules participate in crystallization in contrast to <b>6</b>, and it has been observed that <b>5</b> forms 3D supramolecular structure, while <b>6</b> forms 2D supramolecular structure using both hydrogen bonding and π··· interactions. An investigation of intermolecular closed contacts has been carried out by Hirshfeld surface analysis, and associated 2D fingerprint plots reveal the similarities and differences of TBTA molecules in these six crystal structures. Photoluminescence spectra of all the compounds have been studied, and they reveal that with change of polarity around TBTA luminescent intensity of the compounds has been modified. <i>I</i>–<i>V</i> measurement indicates that <b>3</b> shows semiconducting behavior, and the ITO/<b>3</b>/Al sandwich structure acts as a Schottky barrier diode. The device exhibits an excellent rectification ratio (19 at ±1 V) with an ideality factor of 2.96. The semiconducting behavior of <b>3</b> is attributed to the formation charge assisted hydrogen bonding interactions between acid and base molecules

Tetrabromoterepthalic Acid in Designing Co-crystals and Salts: Modification of Optical Properties and Schottky Barrier Effect

Herein, tetrabromoterepthalic acid (TBTA) is used as the potential co-crystal former with various organic base molecules containing free nitrogen atoms. The crystal structure of TBTA (compound <b>1</b>) has been determined from powder X-ray diffraction (PXRD) data. In a systematic way, we have synthesized hydrated-TBTA (compound <b>2</b>), two salts of TBTA [TBTA^2––4,4′-bipy²⁺ (compound <b>3</b>), 4,4′-bipy = 4,4′-bipyridine, and TBTA^2––(3-AP⁺)₂ (compound <b>4</b>), 3-AP = 3-aminopyridine] and two co-crystals of TBTA [TBTA–DPTZ (compound <b>5</b>), DPTZ = 3,6-di­(pyridyl-2-yl)-1,2,4,5-tetrazine, and TBTA–(3-IP)₂ (compound <b>6</b>), 3-IP = 3-iodopyridine]. All of the compounds were characterized by structural, spectral, and thermal studies. Supramolecular structural analysis reveals that <b>1</b> forms a 2D supramolecular sheet structure by means of O–H···Br hydrogen bonding interactions and hydrated-<b>2</b> forms a 3D supramolecular structure through water mediated hydrogen bonding interactions and π··· interactions. The O–H···N/O¯···H–N⁺ hydrogen bonding interactions between acid and base molecules give rise to 1D supramolecular chain structure in <b>3</b> and supramolecular trimers in <b>4</b>, <b>5</b>, and <b>6</b>. Because of presence of charge assisted O^¯···H–N⁺ hydrogen bonds between acid–base molecules, <b>3</b> and <b>4</b> form hydrogen bonds with solvent water molecules, and also both <b>3</b> and <b>4</b> form 3D supramolecular structures using both hydrogen bonding and π··· interactions. In co-crystal <b>5</b>, solvent water molecules participate in crystallization in contrast to <b>6</b>, and it has been observed that <b>5</b> forms 3D supramolecular structure, while <b>6</b> forms 2D supramolecular structure using both hydrogen bonding and π··· interactions. An investigation of intermolecular closed contacts has been carried out by Hirshfeld surface analysis, and associated 2D fingerprint plots reveal the similarities and differences of TBTA molecules in these six crystal structures. Photoluminescence spectra of all the compounds have been studied, and they reveal that with change of polarity around TBTA luminescent intensity of the compounds has been modified. <i>I</i>–<i>V</i> measurement indicates that <b>3</b> shows semiconducting behavior, and the ITO/<b>3</b>/Al sandwich structure acts as a Schottky barrier diode. The device exhibits an excellent rectification ratio (19 at ±1 V) with an ideality factor of 2.96. The semiconducting behavior of <b>3</b> is attributed to the formation charge assisted hydrogen bonding interactions between acid and base molecules

Tetrabromoterepthalic Acid in Designing Co-crystals and Salts: Modification of Optical Properties and Schottky Barrier Effect

Herein, tetrabromoterepthalic acid (TBTA) is used as the potential co-crystal former with various organic base molecules containing free nitrogen atoms. The crystal structure of TBTA (compound <b>1</b>) has been determined from powder X-ray diffraction (PXRD) data. In a systematic way, we have synthesized hydrated-TBTA (compound <b>2</b>), two salts of TBTA [TBTA^2––4,4′-bipy²⁺ (compound <b>3</b>), 4,4′-bipy = 4,4′-bipyridine, and TBTA^2––(3-AP⁺)₂ (compound <b>4</b>), 3-AP = 3-aminopyridine] and two co-crystals of TBTA [TBTA–DPTZ (compound <b>5</b>), DPTZ = 3,6-di­(pyridyl-2-yl)-1,2,4,5-tetrazine, and TBTA–(3-IP)₂ (compound <b>6</b>), 3-IP = 3-iodopyridine]. All of the compounds were characterized by structural, spectral, and thermal studies. Supramolecular structural analysis reveals that <b>1</b> forms a 2D supramolecular sheet structure by means of O–H···Br hydrogen bonding interactions and hydrated-<b>2</b> forms a 3D supramolecular structure through water mediated hydrogen bonding interactions and π··· interactions. The O–H···N/O¯···H–N⁺ hydrogen bonding interactions between acid and base molecules give rise to 1D supramolecular chain structure in <b>3</b> and supramolecular trimers in <b>4</b>, <b>5</b>, and <b>6</b>. Because of presence of charge assisted O^¯···H–N⁺ hydrogen bonds between acid–base molecules, <b>3</b> and <b>4</b> form hydrogen bonds with solvent water molecules, and also both <b>3</b> and <b>4</b> form 3D supramolecular structures using both hydrogen bonding and π··· interactions. In co-crystal <b>5</b>, solvent water molecules participate in crystallization in contrast to <b>6</b>, and it has been observed that <b>5</b> forms 3D supramolecular structure, while <b>6</b> forms 2D supramolecular structure using both hydrogen bonding and π··· interactions. An investigation of intermolecular closed contacts has been carried out by Hirshfeld surface analysis, and associated 2D fingerprint plots reveal the similarities and differences of TBTA molecules in these six crystal structures. Photoluminescence spectra of all the compounds have been studied, and they reveal that with change of polarity around TBTA luminescent intensity of the compounds has been modified. <i>I</i>–<i>V</i> measurement indicates that <b>3</b> shows semiconducting behavior, and the ITO/<b>3</b>/Al sandwich structure acts as a Schottky barrier diode. The device exhibits an excellent rectification ratio (19 at ±1 V) with an ideality factor of 2.96. The semiconducting behavior of <b>3</b> is attributed to the formation charge assisted hydrogen bonding interactions between acid and base molecules

Tetrabromoterepthalic Acid in Designing Co-crystals and Salts: Modification of Optical Properties and Schottky Barrier Effect

Herein, tetrabromoterepthalic acid (TBTA) is used as the potential co-crystal former with various organic base molecules containing free nitrogen atoms. The crystal structure of TBTA (compound <b>1</b>) has been determined from powder X-ray diffraction (PXRD) data. In a systematic way, we have synthesized hydrated-TBTA (compound <b>2</b>), two salts of TBTA [TBTA^2––4,4′-bipy²⁺ (compound <b>3</b>), 4,4′-bipy = 4,4′-bipyridine, and TBTA^2––(3-AP⁺)₂ (compound <b>4</b>), 3-AP = 3-aminopyridine] and two co-crystals of TBTA [TBTA–DPTZ (compound <b>5</b>), DPTZ = 3,6-di­(pyridyl-2-yl)-1,2,4,5-tetrazine, and TBTA–(3-IP)₂ (compound <b>6</b>), 3-IP = 3-iodopyridine]. All of the compounds were characterized by structural, spectral, and thermal studies. Supramolecular structural analysis reveals that <b>1</b> forms a 2D supramolecular sheet structure by means of O–H···Br hydrogen bonding interactions and hydrated-<b>2</b> forms a 3D supramolecular structure through water mediated hydrogen bonding interactions and π··· interactions. The O–H···N/O¯···H–N⁺ hydrogen bonding interactions between acid and base molecules give rise to 1D supramolecular chain structure in <b>3</b> and supramolecular trimers in <b>4</b>, <b>5</b>, and <b>6</b>. Because of presence of charge assisted O^¯···H–N⁺ hydrogen bonds between acid–base molecules, <b>3</b> and <b>4</b> form hydrogen bonds with solvent water molecules, and also both <b>3</b> and <b>4</b> form 3D supramolecular structures using both hydrogen bonding and π··· interactions. In co-crystal <b>5</b>, solvent water molecules participate in crystallization in contrast to <b>6</b>, and it has been observed that <b>5</b> forms 3D supramolecular structure, while <b>6</b> forms 2D supramolecular structure using both hydrogen bonding and π··· interactions. An investigation of intermolecular closed contacts has been carried out by Hirshfeld surface analysis, and associated 2D fingerprint plots reveal the similarities and differences of TBTA molecules in these six crystal structures. Photoluminescence spectra of all the compounds have been studied, and they reveal that with change of polarity around TBTA luminescent intensity of the compounds has been modified. <i>I</i>–<i>V</i> measurement indicates that <b>3</b> shows semiconducting behavior, and the ITO/<b>3</b>/Al sandwich structure acts as a Schottky barrier diode. The device exhibits an excellent rectification ratio (19 at ±1 V) with an ideality factor of 2.96. The semiconducting behavior of <b>3</b> is attributed to the formation charge assisted hydrogen bonding interactions between acid and base molecules

Tetrabromoterepthalic Acid in Designing Co-crystals and Salts: Modification of Optical Properties and Schottky Barrier Effect

Herein, tetrabromoterepthalic acid (TBTA) is used as the potential co-crystal former with various organic base molecules containing free nitrogen atoms. The crystal structure of TBTA (compound <b>1</b>) has been determined from powder X-ray diffraction (PXRD) data. In a systematic way, we have synthesized hydrated-TBTA (compound <b>2</b>), two salts of TBTA [TBTA^2––4,4′-bipy²⁺ (compound <b>3</b>), 4,4′-bipy = 4,4′-bipyridine, and TBTA^2––(3-AP⁺)₂ (compound <b>4</b>), 3-AP = 3-aminopyridine] and two co-crystals of TBTA [TBTA–DPTZ (compound <b>5</b>), DPTZ = 3,6-di­(pyridyl-2-yl)-1,2,4,5-tetrazine, and TBTA–(3-IP)₂ (compound <b>6</b>), 3-IP = 3-iodopyridine]. All of the compounds were characterized by structural, spectral, and thermal studies. Supramolecular structural analysis reveals that <b>1</b> forms a 2D supramolecular sheet structure by means of O–H···Br hydrogen bonding interactions and hydrated-<b>2</b> forms a 3D supramolecular structure through water mediated hydrogen bonding interactions and π··· interactions. The O–H···N/O¯···H–N⁺ hydrogen bonding interactions between acid and base molecules give rise to 1D supramolecular chain structure in <b>3</b> and supramolecular trimers in <b>4</b>, <b>5</b>, and <b>6</b>. Because of presence of charge assisted O^¯···H–N⁺ hydrogen bonds between acid–base molecules, <b>3</b> and <b>4</b> form hydrogen bonds with solvent water molecules, and also both <b>3</b> and <b>4</b> form 3D supramolecular structures using both hydrogen bonding and π··· interactions. In co-crystal <b>5</b>, solvent water molecules participate in crystallization in contrast to <b>6</b>, and it has been observed that <b>5</b> forms 3D supramolecular structure, while <b>6</b> forms 2D supramolecular structure using both hydrogen bonding and π··· interactions. An investigation of intermolecular closed contacts has been carried out by Hirshfeld surface analysis, and associated 2D fingerprint plots reveal the similarities and differences of TBTA molecules in these six crystal structures. Photoluminescence spectra of all the compounds have been studied, and they reveal that with change of polarity around TBTA luminescent intensity of the compounds has been modified. <i>I</i>–<i>V</i> measurement indicates that <b>3</b> shows semiconducting behavior, and the ITO/<b>3</b>/Al sandwich structure acts as a Schottky barrier diode. The device exhibits an excellent rectification ratio (19 at ±1 V) with an ideality factor of 2.96. The semiconducting behavior of <b>3</b> is attributed to the formation charge assisted hydrogen bonding interactions between acid and base molecules