Next Issue
Previous Issue

Table of Contents

Inorganics, Volume 7, Issue 5 (May 2019)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Cover Story (view full-size image) The aqueous synthesis of metal–organic frameworks (MOFs) at room temperature offers many [...] Read more.
View options order results:
result details:
Displaying articles 1-13
Export citation of selected articles as:
Open AccessReview
Responsive ParaCEST Contrast Agents
Received: 2 May 2019 / Revised: 16 May 2019 / Accepted: 21 May 2019 / Published: 25 May 2019
Viewed by 231 | PDF Full-text (2512 KB) | HTML Full-text | XML Full-text
Abstract
This article aimed at reviewing the advances on the development of paramagnetic complexes used as chemical exchange saturation transfer agents in magnetic resonance imaging. This relatively new type of contrast opens new avenues in the development of MRI probes for molecular imaging, and [...] Read more.
This article aimed at reviewing the advances on the development of paramagnetic complexes used as chemical exchange saturation transfer agents in magnetic resonance imaging. This relatively new type of contrast opens new avenues in the development of MRI probes for molecular imaging, and coordination chemistry lies at the center of such advances. Strategies to detect important biomarkers such as pH, cations, anions, metabolites, enzyme, and O2 were described. The current challenges, limitations, and opportunities in this field of research were discussed. Full article
(This article belongs to the Special Issue MRI Contrast Agents)
Figures

Graphical abstract

Open AccessArticle
Impact of the Subunit Arrangement on the Nonlinear Absorption Properties of Organometallic Complexes with Ruthenium(II) σ-Acetylide and Benzothiadiazole as Building Units §
Received: 29 April 2019 / Revised: 21 May 2019 / Accepted: 22 May 2019 / Published: 24 May 2019
Viewed by 232 | PDF Full-text (2194 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In this paper, the nonlinear absorption properties of two complexes consisting of Ru(C≡CPh)(C≡C)(dppe)2 (dppe = Ph2PCH2CH2PPh2) as electron donor (D) and 4,7-di(2-thienyl)benzo[c][1,2,5]thiadiazole as electron acceptor (A) units in two different arrangement, i.e., A–D–A and [...] Read more.
In this paper, the nonlinear absorption properties of two complexes consisting of Ru(C≡CPh)(C≡C)(dppe)2 (dppe = Ph2PCH2CH2PPh2) as electron donor (D) and 4,7-di(2-thienyl)benzo[c][1,2,5]thiadiazole as electron acceptor (A) units in two different arrangement, i.e., A–D–A and D–A–D, are presented. They were measured in solution by the femtosecond open-aperture Z-scan method. The complexes show moderate two-photon absorption cross-sections σ(2) of several hundred to one thousand GM (here 1 GM = 10−50 cm4 s molecule−1 photon−1). Although they are formed by the same building units, it was found that the two-photon absorption values of the D–A–D arrangement are six times higher than that of the A–D–A one. This difference can be explained by the number of metal cores (one or two ruthenium centers), the geometrical configurations of the complexes (more or less planar), and the resonance enhancement by lowering the intermediate state. Full article
(This article belongs to the Special Issue Metal Complexes as Nonlinear Optical Molecular Materials)
Figures

Graphical abstract

Open AccessArticle
Titanium Doping of the Metallic One-Dimensional Antiferromagnet, Nb12O29
Received: 4 March 2019 / Revised: 7 May 2019 / Accepted: 21 May 2019 / Published: 23 May 2019
Viewed by 290 | PDF Full-text (25371 KB) | HTML Full-text | XML Full-text
Abstract
Monoclinic Nb12O29 undergoes a charge ordering transition to form antiferromagnetic Nb4+ chains (TN ~ 12 K) spaced 15.7 Å apart, which are coupled through mediation from a subset of metallic electrons which are present over all temperature regimes. [...] Read more.
Monoclinic Nb12O29 undergoes a charge ordering transition to form antiferromagnetic Nb4+ chains (TN ~ 12 K) spaced 15.7 Å apart, which are coupled through mediation from a subset of metallic electrons which are present over all temperature regimes. We present the effects of disrupting the delicate electronic equilibrium in monoclinic Nb12O29 through doping Nb4+ (d1) with Ti4+ (d0) ions in the series, TixNb12−xO29. Powder neutron diffraction demonstrates that Ti is distributed over all of the 6 crystallographically distinct Nb positions. Magnetic susceptibility measurements reveal a rapid suppression of the magnetic ordered state on Ti doping, with a 3% percolation threshold consistent with the existence of one-dimensional Nb4+ chains. The reduction of the number of unpaired electrons on Ti4+ doping is shown to depopulate both localised and itinerant electron subsets, demonstrating that they are intrinsic to the properties of the system, which is argued to be a direct consequence of the mixture of bonding schemes within the lattice. Full article
(This article belongs to the Special Issue Magnetic Oxide Materials)
Figures

Figure 1

Open AccessArticle
Transmetalation from Magnesium–NHCs—Convenient Synthesis of Chelating π-Acidic NHC Complexes
Received: 6 May 2019 / Revised: 18 May 2019 / Accepted: 19 May 2019 / Published: 22 May 2019
Viewed by 270 | PDF Full-text (3236 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The synthesis of chelating N-heterocyclic carbene (NHC) complexes with considerable π-acceptor properties can be a challenging task. This is due to the dimerization of free carbene ligands, the moisture sensitivity of reaction intermediates or reagents, and challenges associated with the workup procedure. [...] Read more.
The synthesis of chelating N-heterocyclic carbene (NHC) complexes with considerable π-acceptor properties can be a challenging task. This is due to the dimerization of free carbene ligands, the moisture sensitivity of reaction intermediates or reagents, and challenges associated with the workup procedure. Herein, we report a general route using transmetalation from magnesium–NHCs. Notably, this route gives access to transition-metal complexes in quantitative conversion without the formation of byproducts. It therefore produces transition-metal complexes outperforming the conventional routes based on free or lithium-coordinated carbene, silver complexes, or in situ metalation in dimethyl sulfoxide (DMSO). We therefore propose transmetalation from magnesium–NHCs as a convenient and general route to obtain NHC complexes. Full article
(This article belongs to the Section Organometallic Chemistry)
Figures

Graphical abstract

Open AccessArticle
The Role of Surface Plasmon Resonance of Gold Nanoparticles for the Enhancement of Second Harmonic Generation of Nonlinear Chromophores
Received: 16 April 2019 / Revised: 14 May 2019 / Accepted: 15 May 2019 / Published: 18 May 2019
Viewed by 258 | PDF Full-text (1904 KB) | HTML Full-text | XML Full-text
Abstract
A significant enhancement of the second harmonic generation (SHG) from second-order nonlinear optical (NLO) dyes in solution has been evidenced when these dyes were grafted onto the surface of spherical gold nanoparticles (AuNPs), as compared to their NLO response without AuNPs. The length, [...] Read more.
A significant enhancement of the second harmonic generation (SHG) from second-order nonlinear optical (NLO) dyes in solution has been evidenced when these dyes were grafted onto the surface of spherical gold nanoparticles (AuNPs), as compared to their NLO response without AuNPs. The length, as well as the nature of the spacers between the gold particle and the chromophore, is shown to play an important role, a benzene linker being more favorable to AuNP-4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) interactions, as illustrated by a higher exaltation of the NLO response for DAST molecules linked to AuNP via a phenyl ring as compared to their equivalent with a CH2–CH2 link. Full article
(This article belongs to the Special Issue Metal Complexes as Nonlinear Optical Molecular Materials)
Figures

Graphical abstract

Open AccessArticle
High-Pressure Synthesis of Non-Stoichiometric LixWO3 (0.5 ≤ x ≤ 1.0) with LiNbO3 Structure
Received: 21 April 2019 / Revised: 10 May 2019 / Accepted: 10 May 2019 / Published: 12 May 2019
Viewed by 311 | PDF Full-text (2211 KB) | HTML Full-text | XML Full-text
Abstract
Compounds with the LiNbO3-type structure are important for a variety of applications, such as piezoelectric sensors, while recent attention has been paid to magnetic and electronic properties. However, all the materials reported are stoichiometric. This work reports on the high-pressure synthesis [...] Read more.
Compounds with the LiNbO3-type structure are important for a variety of applications, such as piezoelectric sensors, while recent attention has been paid to magnetic and electronic properties. However, all the materials reported are stoichiometric. This work reports on the high-pressure synthesis of lithium tungsten bronze LixWO3 with the LiNbO3-type structure, with a substantial non-stoichiometry (0.5 ≤ x ≤ 1). Li0.8WO3 exhibit a metallic conductivity. This phase is related to an ambient-pressure perovskite phase (0 ≤ x ≤ 0.5) by the octahedral tilting switching between aaa and a+a+a+. Full article
(This article belongs to the Section Inorganic Solid-State Chemistry)
Figures

Graphical abstract

Open AccessArticle
Modeling the Catalyst Activation Step in a Metal–Ligand Radical Mechanism Based Water Oxidation System
Received: 14 March 2019 / Revised: 31 March 2019 / Accepted: 13 April 2019 / Published: 9 May 2019
Viewed by 223 | PDF Full-text (2287 KB) | HTML Full-text | XML Full-text
Abstract
Designing catalysts for water oxidation (WOCs) that operate at low overpotentials plays an important role in developing sustainable energy conversion schemes. Recently, a mononuclear ruthenium WOC that operates via metal–ligand radical coupling pathway was reported, with a very low barrier for O–O bond [...] Read more.
Designing catalysts for water oxidation (WOCs) that operate at low overpotentials plays an important role in developing sustainable energy conversion schemes. Recently, a mononuclear ruthenium WOC that operates via metal–ligand radical coupling pathway was reported, with a very low barrier for O–O bond formation, that is usually the rate-determining step in most WOCs. A detailed mechanistic understanding of this mechanism is crucial to design highly active oxygen evolution catalysts. Here, we use density functional theory based molecular dynamics (DFT-MD) with an explicit description of the solvent to investigate the catalyst activation step for the [Ru(bpy) 2 (bpy–NO)] 2 + complex, that is considered to be the rate-limiting step in the metal–ligand radical coupling pathway. We find that a realistic description of the solvent environment, including explicit solvent molecules and thermal motion, is crucial for an accurate description of the catalyst activation step, and for the estimation of the activation barriers. Full article
(This article belongs to the Special Issue Recent Advances in Water Oxidation Catalysis)
Figures

Figure 1

Open AccessArticle
Comparing the Acidity of (R3P)2BH-Based Donor Groups in Iridium Pincer Complexes
Received: 31 March 2019 / Revised: 28 April 2019 / Accepted: 29 April 2019 / Published: 7 May 2019
Viewed by 280 | PDF Full-text (3260 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In the current manuscript, we describe the reactivity of a series of iridium(III) pincer complexes with the general formulae [(PEP)IrCl(CO)(H)]n (n = +1, +2) towards base, where PEP is a pincer-type ligand with different central donor groups, and E is the [...] Read more.
In the current manuscript, we describe the reactivity of a series of iridium(III) pincer complexes with the general formulae [(PEP)IrCl(CO)(H)]n (n = +1, +2) towards base, where PEP is a pincer-type ligand with different central donor groups, and E is the ligating atom of this group (E = B, C, N). The donor groups encompass a secondary amine, a phosphine-stabilised borylene and a protonated carbodiphosphorane. As all ligating atoms E exhibit an E–H bond, we addressed the question of wether the coordinated donor group can be deprotonated in competition to the reductive elimination of HCl from the iridium(III) centre. Based on experimental and quantum chemical investigations, it is shown that the ability for deprotonation of the coordinated ligand decreases in the order of (R3P)2CH+ > R2NH > (R3P)2BH. The initial product of the reductive elimination of HCl from [(PBP)IrCl(CO)(H)]n (1c), the square planar iridium(I) complex, [(PBP)Ir(CO)]+ (3c), was found to be unstable and further reacts to [(PBP)Ir(CO)2]+ (5c). Comparing the C–O stretching vibrations of the latter with those of related complexes, it is demonstrated that neutral ligands based on tricoordinate boron are very strong donors. Full article
(This article belongs to the Special Issue Metal Complexes Containing Boron Based Ligands)
Figures

Graphical abstract

Open AccessCommunication
Functionalizing NaGdF4:Yb,Er Upconverting Nanoparticles with Bone-Targeting Phosphonate Ligands: Imaging and In Vivo Biodistribution
Received: 11 December 2018 / Revised: 12 April 2019 / Accepted: 19 April 2019 / Published: 30 April 2019
Viewed by 311 | PDF Full-text (1595 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Lanthanide-doped upconverting nanoparticles (UCNPs) transform near infrared light (NIR) into higher-energy UV and visible light by multiphotonic processes. Owing to such unique feature, UCNPs have found application in optical imaging and have been investigated for the NIR light activation of prodrugs, including transition [...] Read more.
Lanthanide-doped upconverting nanoparticles (UCNPs) transform near infrared light (NIR) into higher-energy UV and visible light by multiphotonic processes. Owing to such unique feature, UCNPs have found application in optical imaging and have been investigated for the NIR light activation of prodrugs, including transition metal complexes of interest in photochemotherapy. Besides, UCNPs also function as magnetic resonance imaging (MRI) contrast agents and positron emission tomography (PET) probes when labelled with radionuclides such as 18F. In this contribution, we report on a new series of phosphonate-functionalized NaGdF4:Yb,Er UCNPs that show affinity for hydroxyapatite (inorganic constituent of bones), and we discuss their potential as bone targeting multimodal (MRI/PET) imaging agents. In vivo biodistribution studies of 18F-labelled NaGdF4:Yb,Er UCNPs in rats indicate that surface functionalization with phosphonates favours the accumulation of nanoparticles in bones over time. PET results reveal leakage of 18F for phosphonate-functionalized NaGdF4:Yb,Er and control nanomaterials. However, Gd was detected in the femur for phosphonate-capped UCNPs by ex vivo analysis using ICP-MS, corresponding to 6–7% of the injected dose. Full article
Figures

Graphical abstract

Open AccessReview
Potential of MRI in Radiotherapy Mediated by Small Conjugates and Nanosystems
Received: 6 April 2019 / Revised: 25 April 2019 / Accepted: 25 April 2019 / Published: 30 April 2019
Viewed by 283 | PDF Full-text (2920 KB) | HTML Full-text | XML Full-text
Abstract
Radiation therapy has made tremendous progress in oncology over the last decades due to advances in engineering and physical sciences in combination with better biochemical, genetic and molecular understanding of this disease. Local delivery of optimal radiation dose to a tumor, while sparing [...] Read more.
Radiation therapy has made tremendous progress in oncology over the last decades due to advances in engineering and physical sciences in combination with better biochemical, genetic and molecular understanding of this disease. Local delivery of optimal radiation dose to a tumor, while sparing healthy surrounding tissues, remains a great challenge, especially in the proximity of vital organs. Therefore, imaging plays a key role in tumor staging, accurate target volume delineation, assessment of individual radiation resistance and even personalized dose prescription. From this point of view, radiotherapy might be one of the few therapeutic modalities that relies entirely on high-resolution imaging. Magnetic resonance imaging (MRI) with its superior soft-tissue resolution is already used in radiotherapy treatment planning complementing conventional computed tomography (CT). Development of systems integrating MRI and linear accelerators opens possibilities for simultaneous imaging and therapy, which in turn, generates the need for imaging probes with therapeutic components. In this review, we discuss the role of MRI in both external and internal radiotherapy focusing on the most important examples of contrast agents with combined therapeutic potential. Full article
(This article belongs to the Special Issue MRI Contrast Agents)
Figures

Graphical abstract

Open AccessArticle
Reactive Heterobimetallic Complex Combining Divalent Ytterbium and Dimethyl Nickel Fragments
Received: 8 March 2019 / Revised: 29 March 2019 / Accepted: 17 April 2019 / Published: 26 April 2019
Viewed by 443 | PDF Full-text (2633 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This article presented the synthesis and characterization of original heterobimetallic species combining a divalent lanthanide fragment and a divalent nickel center bridged by the bipyrimidine ligand, a redox-active ligand. X-ray crystal structures were obtained for the Ni monomer (bipym)NiMe2, 1, [...] Read more.
This article presented the synthesis and characterization of original heterobimetallic species combining a divalent lanthanide fragment and a divalent nickel center bridged by the bipyrimidine ligand, a redox-active ligand. X-ray crystal structures were obtained for the Ni monomer (bipym)NiMe2, 1, as well as the heterobimetallic dimer compounds, Cp*2Yb(bipym)NiMe2, 2, along with 1H solution NMR, solid-state magnetic data, and DFT calculations only for 1. The reactivity with CO was investigated on both compounds and the stoichiometric acetone formation is discussed based on kinetic and mechanistic studies. The key role of the lanthanide fragment was demonstrated by the relatively slow CO migratory insertion step, which indicated the stability of the intermediate. Full article
(This article belongs to the Special Issue Binuclear Complexes)
Figures

Graphical abstract

Open AccessArticle
Assessment of Double-Hybrid Density Functional Theory for Magnetic Exchange Coupling in Manganese Complexes
Received: 7 April 2019 / Revised: 18 April 2019 / Accepted: 22 April 2019 / Published: 26 April 2019
Viewed by 354 | PDF Full-text (600 KB) | HTML Full-text | XML Full-text
Abstract
Molecular systems containing magnetically interacting (exchange-coupled) manganese ions are important in catalysis, biomimetic chemistry, and molecular magnetism. The reliable prediction of exchange coupling constants with quantum chemical methods is key for tracing the relationships between structure and magnetic properties in these systems. Density [...] Read more.
Molecular systems containing magnetically interacting (exchange-coupled) manganese ions are important in catalysis, biomimetic chemistry, and molecular magnetism. The reliable prediction of exchange coupling constants with quantum chemical methods is key for tracing the relationships between structure and magnetic properties in these systems. Density functional theory (DFT) in the broken-symmetry approach has been employed extensively for this purpose and hybrid functionals with moderate levels of Hartree–Fock exchange admixture have often been shown to perform adequately. Double-hybrid density functionals that introduce a second-order perturbational contribution to the Kohn–Sham energy are generally regarded as a superior approach for most molecular properties, but their performance remains unexplored for exchange-coupled manganese systems. An assessment of various double-hybrid functionals for the prediction of exchange coupling constants is presented here using a set of experimentally characterized dinuclear manganese complexes that cover a wide range of exchange coupling situations. Double-hybrid functionals perform more uniformly compared to conventional DFT methods, but they fail to deliver improved accuracy or reliability in the prediction of exchange coupling constants. Reparametrized double-hybrid density functionals (DHDFs) perform no better, and most often worse, than the original B2-PLYP double-hybrid method. All DHDFs are surpassed by the hybrid-meta-generalized gradient approximation (GGA) TPSSh functional. Possible directions for future methodological developments are discussed. Full article
(This article belongs to the Special Issue Applications of Density Functional Theory in Inorganic Chemistry)
Figures

Figure 1

Open AccessArticle
Green Synthesis of a Functionalized Zirconium-Based Metal–Organic Framework for Water and Ethanol Adsorption
Received: 8 April 2019 / Revised: 19 April 2019 / Accepted: 21 April 2019 / Published: 26 April 2019
Viewed by 660 | PDF Full-text (1593 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Aqueous synthesis of metal–organic frameworks (MOFs) at room temperature offers many advantages such as reduction in the generation of toxic byproducts and operation costs, as well as increased safety in the material’s production. Functional group-bearing MOFs have received growing attention compared to nonfunctionalized [...] Read more.
Aqueous synthesis of metal–organic frameworks (MOFs) at room temperature offers many advantages such as reduction in the generation of toxic byproducts and operation costs, as well as increased safety in the material’s production. Functional group-bearing MOFs have received growing attention compared to nonfunctionalized analogues due to enhanced adsorption properties of the former in many cases. Here, we report an aqueous solution-based synthesis of a robust zirconium MOF, UiO-66-NO2, at room temperature. We evaluated the phase purity, porosity, thermal stability, particle morphology and size of the resulting material. High uptake, as well as near complete recyclability of water and ethanol vapor isotherms at room temperature supports the potential of UiO-66-NO2 as a solid adsorbent in adsorption-based cooling applications or water harvesting systems. Full article
(This article belongs to the Special Issue Functional Coordination Polymers and Metal–Organic Frameworks)
Figures

Graphical abstract

Inorganics EISSN 2304-6740 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top