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1.
Gastroenterology ; 164(6): 937-952.e13, 2023 05.
Article in English | MEDLINE | ID: mdl-36657529

ABSTRACT

BACKGROUND & AIMS: Tissue fibrosis results from uncontrolled healing responses leading to excessive mesenchymal cell activation and collagen and other extracellular matrix deposition. In the gastrointestinal tract, fibrosis leads to narrowing of the lumen and stricture formation. A drug treatment to prevent fibrosis and strictures in the gastrointestinal tract would be transformational for patient care. We aimed to develop a stricture treatment with the following characteristics and components: a small molecule with strong antifibrotic effects that is delivered locally at the site of the stricture to ensure correct lesional targeting while protecting the systemic circulation, and that is formulated with sustained-release properties to act throughout the wound healing processes. METHODS: A high-throughput drug screening was performed to identify small molecules with antifibrotic properties. Next, we formulated an antifibrotic small molecule for sustained release and tested its antifibrotic potential in 3 animal models of fibrosis. RESULTS: Sulconazole, a US Food and Drug Administration-approved drug for fungal infections, was found to have strong antifibrotic properties. Sulconazole was formulated as sulconazole nanocrystals for sustained release. We found that sulconazole nanocrystals provided superior or equivalent fibrosis prevention with less frequent dosing in mouse models of skin and intestinal tissue fibrosis. In a patient-like swine model of bowel stricture, a single injection of sulconazole nanocrystals prevented stricture formation. CONCLUSIONS: The current data lay the foundation for further studies to improve the management of a range of diseases and conditions characterized by tissue fibrosis.


Subject(s)
Collagen , Extracellular Matrix , Mice , Animals , Swine , Constriction, Pathologic , Delayed-Action Preparations , Extracellular Matrix/pathology , Fibrosis
2.
J Biomed Mater Res B Appl Biomater ; 109(9): 1271-1282, 2021 09.
Article in English | MEDLINE | ID: mdl-33373104

ABSTRACT

Wound healing attempts to maintain homeostasis in the wound while minimizing the risk of infection to the tissue by foreign agents, such as opportunistic bacterial pathogens. Biofilms established by these pathogens are a common cause of chronic infections that slow the healing process. Preparation of skin wound healing devices comprised of electrospun proteins associated with skin have been shown to accelerate the healing process relative to conventional wound dressings. In this work, we have developed electrospinning methods to incorporate the antimicrobial ionic liquid/deep eutectic solvent choline geranate (CAGE) into these devices. Integration of CAGE into the dressing material was verified via 1 H nuclear magnetic resonance spectrometry, and the effect on the material property of the resultant devices were assessed using scanning electron microscopy. CAGE-containing devices demonstrate a concentration-dependent inactivation of exogenously applied solutions of both gram-positive and gram-negative pathogens (Enterococcus sp and Pseudomonas aeruginosa, respectively), but maintain their ability to serve as a compatible platform for proliferation of human dermal neonatal fibroblasts.


Subject(s)
Anti-Infective Agents/chemistry , Biocompatible Materials/chemistry , Choline/chemistry , Persistent Infection/drug therapy , Pseudomonas aeruginosa/drug effects , Tissue Scaffolds/chemistry , Wound Healing/drug effects , Administration, Cutaneous , Anti-Infective Agents/pharmacology , Bandages , Biofilms , Choline/pharmacology , Cross-Linking Reagents/chemistry , Drug Liberation , Fibroblasts/chemistry , Humans , Ionic Liquids/chemistry , Microbial Sensitivity Tests , Skin , Tissue Engineering
3.
PLoS One ; 14(9): e0222211, 2019.
Article in English | MEDLINE | ID: mdl-31527873

ABSTRACT

Choline geranate (also described as Choline And GEranic acid, or CAGE) has been developed as a novel biocompatible antiseptic material capable of penetrating skin and aiding the transdermal delivery of co-administered antibiotics. The antibacterial properties of CAGE were analyzed against 24 and 72 hour old biofilms of 11 clinically isolated ESKAPE pathogens (defined as Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter sp, respectively), including multidrug resistant (MDR) isolates. CAGE was observed to eradicate in vitro biofilms at concentrations as low as 3.56 mM (0.156% v:v) in as little as 2 hours, which represents both an improved potency and rate of biofilm eradication relative to that reported for most common standard-of-care topical antiseptics in current use. In vitro time-kill studies on 24 hour old Staphylococcus aureus biofilms indicate that CAGE exerts its antibacterial effect upon contact and a 0.1% v:v solution reduced biofilm viability by over three orders of magnitude (a 3log10 reduction) in 15 minutes. Furthermore, disruption of the protective layer of exopolymeric substances in mature biofilms of Staphylococcus aureus by CAGE (0.1% v:v) was observed in 120 minutes. Insight into the mechanism of action of CAGE was provided with molecular modeling studies alongside in vitro antibiofilm assays. The geranate ion and geranic acid components of CAGE are predicted to act in concert to integrate into bacterial membranes, affect membrane thinning and perturb membrane homeostasis. Taken together, our results show that CAGE demonstrates all properties required of an effective topical antiseptic and the data also provides insight into how its observed antibiofilm properties may manifest.


Subject(s)
Anti-Infective Agents, Local/pharmacology , Choline/pharmacology , Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Biofilms/drug effects , Microbial Sensitivity Tests/methods
4.
Chem Commun (Camb) ; 53(85): 11682-11685, 2017 Oct 24.
Article in English | MEDLINE | ID: mdl-29019359

ABSTRACT

Ionic liquids containing lanthanide halide anions give the opportunity to investigate magnetic behaviour in non-ordered systems. Reported herein is the synthesis and characterization of ionic liquids containing a series of lanthanide halide anions, with the resulting materials displaying unusual behaviour below 50 K. Specifically, the ionic liquid structural glass formation appears to drive magnetic behaviour due to cluster formation of the anions during rapid cooling. This system presents a possible probe to study the dynamics of glass forming materials.

5.
Proc Natl Acad Sci U S A ; 111(37): 13313-8, 2014 Sep 16.
Article in English | MEDLINE | ID: mdl-25157174

ABSTRACT

Biofilm-protected microbial infections in skin are a serious health risk that remains to be adequately addressed. The lack of progress in developing effective treatment strategies is largely due to the transport barriers posed by the stratum corneum of the skin and the biofilm. In this work, we report on the use of Ionic Liquids (ILs) for biofilm disruption and enhanced antibiotic delivery across skin layers. We outline the syntheses of ILs, analysis of relevant physicochemical properties, and subsequent neutralization effects on two biofilm-forming pathogens: Pseudomonas aeruginosa and Salmonella enterica. Further, the ILs were also examined for cytotoxicity, skin irritation, delivery of antibiotics through the skin, and treatment of biofilms in a wound model. Of the materials examined, choline-geranate emerged as a multipurpose IL with excellent antimicrobial activity, minimal toxicity to epithelial cells as well as skin, and effective permeation enhancement for drug delivery. Specifically, choline-geranate was comparable with, or more effective than, bleach treatment against established biofilms of S. enterica and P. aeruginosa, respectively. In addition, choline-geranate increased delivery of cefadroxil, an antibiotic, by >16-fold into the deep tissue layers of the skin without inducing skin irritation. The in vivo efficacy of choline-geranate was validated using a biofilm-infected wound model (>95% bacterial death after 2-h treatment). This work establishes the use of ILs for simultaneous enhancement of topical drug delivery and antibiotic activity.


Subject(s)
Drug Delivery Systems , Ionic Liquids/pharmacology , Pseudomonas aeruginosa/physiology , Salmonella enterica/physiology , Administration, Cutaneous , Biofilms/drug effects , Cell Death/drug effects , Epithelial Cells/cytology , Epithelial Cells/drug effects , Humans , Irritants/toxicity , Microbial Sensitivity Tests , Pseudomonas aeruginosa/drug effects , Reproducibility of Results , Salmonella enterica/drug effects , Skin/drug effects , Skin, Artificial/microbiology , Spectroscopy, Fourier Transform Infrared
6.
Anal Chem ; 84(21): 9169-75, 2012 Nov 06.
Article in English | MEDLINE | ID: mdl-23066794

ABSTRACT

Analytical capabilities to identify dyes associated with structurally robust wool fibers would critically assist crime-scene and explosion-scene forensics. Nondestructive separation of dyes from wool, removal of contaminants, and dye analysis by MALDI- or ESI-MS, were achieved in a single-pot, ionic liquid-based method. Ionic liquids (ILs) that readily denature the wool α-keratin structure have been identified and are conducive to small volume, high-throughput analysis for accelerated threat-response times. Wool dyed with commercial or natural, plant-based dyes have unique signatures that allow classification and matching of samples and identification of dyestuffs. Wool released 0.005 mg of dye per mg of dyed wool into the IL, allowing for analysis of single-thread sample sizes. The IL + dye mixture promotes sufficient ionization in MALDI-MS: addition of common MALDI matrices does not improve analysis of anionic wool dyes. An inexpensive, commercially available tetrabutylphosponium chloride IL was discovered to be capable of denaturing wool and was determined to be the most effective for this readily fieldable method.


Subject(s)
Coloring Agents/analysis , Coloring Agents/isolation & purification , Ionic Liquids/chemistry , Wool/chemistry , Animals , Coloring Agents/chemistry , Limit of Detection , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
7.
Inorg Chem ; 51(14): 7520-8, 2012 Jul 16.
Article in English | MEDLINE | ID: mdl-22746404

ABSTRACT

[Ni(HF(2))(3-Clpy)(4)]BF(4) (py = pyridine) is a simple one-dimensional (1D) coordination polymer composed of compressed NiN(4)F(2) octahedra that form chains with bridging HF(2)(-) ligands. In spite of significant distortion of the HF(2)(-) bridge, a quasi-1D antiferromagnetic (AFM) behavior was observed with J(FHF) = 4.86 K.

8.
Dalton Trans ; 41(24): 7235-43, 2012 Jun 28.
Article in English | MEDLINE | ID: mdl-22569844

ABSTRACT

A tetragonal polymorph of [Ni(HF(2))(pyz)(2)]PF(6) (designated ß) is isomorphic to its SbF(6)-congener at 295 K and features linear Ni-FHF-Ni pillars. Enhancements in the spin exchange (J(FHF) = 7.7 K), Néel temperature (T(N) = 7 K), and critical field (B(c) = 24 T) were found relative to monoclinic α-PF(6). DFT reveals that the HF(2)(-) bridges are significantly better mediators of magnetic exchange than pyz (J(pyz)), where J(FHF) ≈ 3J(pyz), thus leading to quasi-1D behavior. Spin density resides on all atoms of the HF(2)(-) bridge whereas N-donor atoms of the pyz ring bear most of the density.

9.
Inorg Chem ; 51(5): 2728-30, 2012 Mar 05.
Article in English | MEDLINE | ID: mdl-22339585

ABSTRACT

The promotion for hydrogen release from ammonia-borane (AB) was observed in the presence of ZIF-8. Even at concentrations of ZIF-8 as low as 0.25 mol %, a reduction of the onset temperature for dehydrogenation accompanies an increase in both the rate and amount of hydrogen released from AB.

10.
Inorg Chem ; 50(13): 5990-6009, 2011 Jul 04.
Article in English | MEDLINE | ID: mdl-21598910

ABSTRACT

[Ni(HF(2))(pyz)(2)]X {pyz = pyrazine; X = PF(6)(-) (1), SbF(6)(-) (2)} were structurally characterized by synchrotron X-ray powder diffraction and found to possess axially compressed NiN(4)F(2) octahedra. At 298 K, 1 is monoclinic (C2/c) with unit cell parameters, a = 9.9481(3), b = 9.9421(3), c = 12.5953(4) Å, and ß = 81.610(3)° while 2 is tetragonal (P4/nmm) with a = b = 9.9359(3) and c = 6.4471(2) Å and is isomorphic with the Cu-analogue. Infinite one-dimensional (1D) Ni-FHF-Ni chains propagate along the c-axis which are linked via µ-pyz bridges in the ab-plane to afford three-dimensional polymeric frameworks with PF(6)(-) and SbF(6)(-) counterions occupying the interior sites. A major difference between 1 and 2 is that the Ni-F-H bonds are bent (∼157°) in 1 but are linear in 2. Ligand field calculations (LFT) based on an angular overlap model (AOM), with comparison to the electronic absorption spectra, indicate greater π-donation of the HF(2)(-) ligand in 1 owing to the bent Ni-F-H bonds. Magnetic susceptibility data for 1 and 2 exhibit broad maxima at 7.4 and 15 K, respectively, and λ-like peaks in dχT/dT at 6.2 and 12.2 K that are ascribed to transitions to long-range antiferromagnetic order (T(N)). Muon-spin relaxation and specific heat studies confirm these T(N)'s. A comparative analysis of χ vs T to various 1D Heisenberg/Ising models suggests moderate antiferromagnetic interactions, with the primary interaction strength determined to be 3.05/3.42 K (1) and 5.65/6.37 K (2). However, high critical fields of 19 and 37.4 T obtained from low temperature pulsed-field magnetization data indicate that a single exchange constant (J(1D)) alone is insufficient to explain the data and that residual terms in the spin Hamiltonian, which could include interchain magnetic couplings (J(⊥)), as mediated by Ni-pyz-Ni, and single-ion anisotropy (D), must be considered. While it is difficult to draw absolute conclusions regarding the magnitude (and sign) of J(⊥) and D based solely on powder data, further support offered by related Ni(II)-pyz compounds and our LFT and density-functional theory (DFT) results lead us to a consistent quasi-1D magnetic description for 1 and 2.


Subject(s)
Electrons , Magnetics , Organometallic Compounds/chemistry , Quantum Theory , Hydrofluoric Acid/chemistry , Molecular Structure , Nickel/chemistry , Organometallic Compounds/chemical synthesis , Pyrazines/chemistry
11.
Anal Chem ; 83(8): 2921-30, 2011 Apr 15.
Article in English | MEDLINE | ID: mdl-21410201

ABSTRACT

Room temperature ionic liquids, or RTILs, based on tetraalkylphosphonium (PR(4)(+)) cations were used as the basis of a platform that enables separation of dyes from textiles, extraction of dyes from aqueous solution, and identification of the dyes by MALDI-MS in a single experimental step for forensic purposes. Ionic liquids were formed with PR(4)(+) cations and ferulate (FA), α-cyano-4-hydroxycinnamate (CHCA), and 2,5-dihydroxybenzoate (DHB) anions. The use of tetraalkylphosphonium-based ionic liquids in MALDI-MS allowed detection of small molecule dyes without addition of a traditional solid MALDI matrix.


Subject(s)
Coloring Agents/analysis , Ionic Liquids/chemistry , Organophosphorus Compounds/chemistry , Ionic Liquids/chemical synthesis , Molecular Structure , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Stereoisomerism
12.
Chem Commun (Camb) ; 46(11): 1848-50, 2010 Mar 21.
Article in English | MEDLINE | ID: mdl-20198229

ABSTRACT

Herein we describe the unique luminescent behavior observed in [Ce(IV)(W(5)O(18))(2)](8-) clusters and examine the photophysical properties using density functional theory.

13.
Chem Commun (Camb) ; (4): 447-9, 2008 Jan 28.
Article in English | MEDLINE | ID: mdl-18188463

ABSTRACT

A series of ionic liquids containing different paramagnetic anions have been prepared and all show paramagnetic behavior with potential applications for magnetic and electrochromic switching as well as novel magnetic transport; also, the tetraalkylphosphonium-based ionic liquids reveal anomalous magnetic behavior.

14.
Chem Commun (Camb) ; (3): 272-4, 2006 Jan 21.
Article in English | MEDLINE | ID: mdl-16391731

ABSTRACT

An intriguing and novel charge-transfer complex between dimethyldihydrophenazine and diethylviologen has been crystallized from an ionic liquid at room temperature, resulting in an interesting stacking motif of interrupted D***A***D type triads: efficient formation of the complex is seen within an ionic liquid and acetone, with the complex absorbing strongly across nearly the entire visible-NIR spectral region.

15.
Magn Reson Chem ; 42(1): 71-5, 2004 Jan.
Article in English | MEDLINE | ID: mdl-14745820

ABSTRACT

The ionic liquids 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) and 1-methyl-3-propylimidazolium tetrafluoroborate ([PMIM][BF4]) were studied by H,H-NOESY NMR using a cross-relaxation matrix analysis. Cross-peak intensities are seen to increase with increasing mixing time. Experimental and theoretical hydrogen-hydrogen distances are in agreement at short mixing times (50 ms). Mixing times longer than 50 ms result in an increasing contribution of spin diffusion that produces unrealistically short hydrogen-hydrogen distances. Gas-phase ab initio molecular structures are obtained using Hartree-Fock (HF) and density functional theory (B3LYP) methods at the 6311 + G(2d,p) basis set level. The hydrogen-hydrogen distances obtained from the theoretical structures are in reasonable agreement with those calculated from the cross-relaxation matrices.


Subject(s)
Imidazoles/chemistry , Ions/chemistry , Magnetic Resonance Spectroscopy/methods , Spin Labels , Diffusion , Models, Chemical , Molecular Structure , Time Factors
16.
J Org Chem ; 68(9): 3367-79, 2003 May 02.
Article in English | MEDLINE | ID: mdl-12713334

ABSTRACT

Chemical reduction of 2,4,6-tricyano-1,3,5-triazine, TCT, results in the formation of an unstable radical anion that undergoes immediate dimerization at a ring carbon to form [C(12)N(12)](2-), [TCT](2)(2-), characterized by a long 1.570 (4) A central C[bond]C. [TCT](2)(2-) can decompose into the radical anion of 4,4',6,6'-tetracyano-2,2'-bitriazine, [TCBT]*-, the one-electron reduced form of planar (D(2h)) TCBT, which is also structurally characterized as the [TMPD][TCBT] charge-transfer complex (TMPD = N,N,N',N'-tetramethyl-p-phenylenediamine) with a 1.492 (2) A central sp(2)[bond]sp(2) C[bond]C. Although crystals could not be obtained for the radical anion [TCBT]*-, the electrochemistry (E degrees = +0.03 V), EPR (g = 2.003, (2)A((14)N) = 3.347 G, and (4)A((14)N) = 0.765 G and a line width of 0.24 G), and theoretical calculations support the formation of [TCBT]*-. In addition, thermolysis of [TCT](2)(2-) yields [TCBT]*-. Chemical reduction of 2,4,6-tricyanobenzene, TCB, forms an unstable radical anion that immediately undergoes dimerization at a ring carbon to form [C(12)H(6)N(6)](2-), [TCB](2)(2-), which has a long 1.560 (5) A central C[bond]C. Reaction of TCT with tetrathiafulvalene (TTF) forms structurally characterized [TTF][TCT], and in the presence of water, TCT hydrolyzes to 2,4-dicyano-6-hydroxy-s-triazine, DCTOH. In contrast, the reaction of TCT with TMPD forms [TMPD][TCT], which in the presence of water forms structurally characterized [HTMPD](+)[DCTO](-).

17.
Chemistry ; 8(21): 4894-908, 2002 Nov 04.
Article in English | MEDLINE | ID: mdl-12397591

ABSTRACT

Three groups of singlet ground state [TCNE](2) (2-) (TCNE=tetracyanoethylene) dimers with characteristic intradimer CC separations (r) and dihedral angles (d) [i.e., group S(t) (r approximately 1.6 A; d=180 degrees ), L(t) (r approximately 3.5 A; d=180 degrees ), and L(c) (r approximately 2.9 A; d= approximately 0 degrees ); notation: S/L: short/long bond length; subscript t/c: trans/cis, respectively] are experimentally characterized. The S(t) group is comprised of sigma-dimers of [TCNE](.-) and octacyanobutanediide, [C(4)(CN)(8)](2-), which have a typical, albeit long, sp(3)-sp(3) sigma bond (r approximately 1.6 A) between each [TCNE](.-) moiety and characteristic nu(CN), nu(CC), and delta(CCN) IR absorptions. The L groups are structurally characterized as pi-dimers of [TCNE](.-) that are either eclipsed with r approximately 2.9 A (L(c)) and the nitriles bend away from the nominal TCNE plane away from the center of the dimer by 5.0 degrees (approximately sp(2.17)) or are noneclipsed with r approximately 3.5 A (L(t)) and the nitriles bend toward the center of the dimer by 1.9 degrees ( approximately sp(2.06)). Ab initio computations on isolated dimers were used to study the formation and stability of these exceptionally long CC (> or =2.9 A) bonding interactions as well as the process of pi-[TCNE](2) (2-) dimer formation for the L(c) and L(t) groups. The results of these computational studies show that the ground-state potential curve is that of a closed-shell/open-shell singlet, depending on the distance. The short S(t) group (r approximately 1.6 A) of dimers in this surface are true minimum-energy structures; however, the L(t) and L(c) groups are unstable, although two different nonphysical minima are found when imposing a double occupancy of the orbitals. These minima are metastable relative to dissociation into the isolated [TCNE](.-) units. Consequently, the existence of dimer dianions in crystals is due to cation.[TCNE](-) interactions, which provide the electrostatic stabilization necessary to overcome the intradimer electrostatic repulsion. This cation-mediated pi*-pi* [TCNE](-).[TCNE](-) interaction complies with Pauling's definition of a chemical bond. This bonding interaction involves the pi* orbitals of each fragment, and arise from the overlap of the b(2g) SOMO on each of the two [TCNE](.-)s to form a filled b(2u) [TCNE](2) (2-) orbital. Although a pi dimer typically forms, if the fragments are close enough a sigma dimer can form. Due to the presence of cation-mediated intradimer CC bonding interactions the L(c) group of pi-[TCNE](2) (2-) dimers exhibits experimentally observable nu(CN) IR absorptions at 2191+/-2 (m), 2173+/-3 (s), and 2162+/-3 cm(-1) (s) and nu(CC) at 1364+/-3 cm(-1) (s) as well as a new UV-Vis feature in the range of 15 000 to 18 200 cm(-1) (549 to 667 nm) and averaging 16 825+/-1180 cm(-1) (594 nm) assigned to the predicted new intradimer (1)A(1g) --> (1)B(1u) transition and is purple on reflected light. Upon cooling to 77 K in 2-methyl tetrahydrofuran, this new band occurs at 18 940 cm(-1) (528 nm) for [[Et(4)N](+)](2)[TCNE](2) (2-), and the yellow solution turns deep red. Group L(t) is characterized by nu(CN) absorptions at 2215+/-2, 2197+/-3, and 2180+/-4 cm(-1) and nu(CC) at 1209+/-9 cm(-1) (w), while group S(T) has nu(CN) bands at 2215+/-4, 2157+/-3, and 2107+/-4 cm(-1) and nu(CC) at 1385+/-1 cm(-1) (vs).

18.
Inorg Chem ; 41(18): 4708-14, 2002 Sep 09.
Article in English | MEDLINE | ID: mdl-12206694

ABSTRACT

By using the tripodal tetradentate ligand tris(2-benzimidazolylmethyl)amine (H(3)ntb), which can have several charge states depending on the number of secondary amine protons, mononuclear octahedral and dinuclear trigonal bipyramidal Fe(III) complexes were prepared. The reaction of mononuclear octahedral [Fe(III)(H(3)ntb)Cl(2)]ClO(4), 1, with 3 equiv of sec-butylamine in methanol led to the formation of mononuclear cis-dimethoxo octahedral Fe(III)(H(2)ntb)(OMe)(2), 2. One equivalent of the sec-butylamine was used to generate the monoanionic H(2)ntb(-) ligand where one of the three amines in the benzimidazolyl groups was deprotonated. The remaining 2 equiv were used to generate two methoxides that were coordinated to the octahedral Fe(III) ion in a cis fashion as demonstrated by the chlorides in 1. Reaction of 1 with excess (7 equiv) sec-butylamine generated the doubly deprotonated dianionic Hntb(2-) that stabilized the dinuclear mu-oxo Fe(III)(2)O(Hntb)(2), 3, adopting a five-coordinate trigonal bipyramidal geometry. The magnetic data for 3 are consistent with the antiferromagnetically coupled Fe(III) (S = 5/2) sites with the coupling constant J = -127 cm(-1).

19.
J Am Chem Soc ; 124(23): 6613-25, 2002 Jun 12.
Article in English | MEDLINE | ID: mdl-12047182

ABSTRACT

We report the supramolecular chemistry of several metal complexes of N-(4-pyridyl)benzamide (NPBA) with the general formula [Ma(NPBA)2AbSc], where M = Co2+, Ni2+, Zn2+, Mn2+, Cu2+, Ag+; A = NO3-, OAc-; S = MeOH, H2O; a = 0, 1, 2; b = 0, 1, 2, 4; and c = 0, 2. NPBA contains structural features that can engage in three modes of intermolecular interactions: (1) metal-ligand coordination, (2) hydrogen bonding, and (3) pi-pi stacking. NPBA forms one-dimensional (1-D) chains governed by hydrogen bonding, but when reacted with metal ions, it generates a wide variety of supramolecular scaffolds that control the arrangement of periodic nanostructures and form 1- (2-4), 2- (5), or 3-D (6-10) solid-state networks of hydrogen bonding and pi-pi stacking interactions in the crystal. Isostructural 7-9 exhibit a 2-D hydrogen bonding network that promotes topotaxial growth of single crystals of their isostructural family and generates crystal composites with two (11) and three (12) different components. Furthermore, 7-9 can also form crystalline solid solutions (M,M')(NPBA)2(NO3)2(MeOH)2 (M, M' = Co2+, Ni2+, or Zn2+, 13-16), where mixtures of Co2+, Ni2+, and Zn2+ share the same crystal lattice in different proportions to allow the formation of materials with modulated magnetic moments. Finally, we report the effects that multidimensional noncovalent networks exert on the magnetic moments between 2 and 300 K of 1-D (4), 2-D (5), and 3-D (7, 8, 10, and 13-16) paramagnetic networks.


Subject(s)
Benzamides/chemistry , Metals/chemistry , Organometallic Compounds/chemistry , Crystallization , Hydrogen Bonding , Magnetics , Models, Molecular , Molecular Conformation , Structure-Activity Relationship
20.
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