Transition metal complexes of the PPO/POP ligand: variable coordination chemistry and photo-luminescence properties

In the current work the tautomeric equilibrium between tetraphenyldiphosphoxane (Ph$_2$P–O–PPh$_2$, POP) and tetraphenyldiphosphine monoxide (Ph$_2$P–P([double bond, length as m-dash]O)Ph$_2$, PPO) in the absence and presence of transition metal precursors is investigated. Whereas with hard transition metal ions, such as Fe(II) and Y(III), PPO-type complexes, such as [FeCl$_2$(PPO)$_2$] and [YCl$_3$(THF)$_2$(PPO)], are formed, softer transition metals ions tend to form so-called coordination stabilised tautomers of the POP ligand form, such as [Cu$_2$(MeCN)$_3$(μ$_2$-POP)$_2$](PF$_6$)$_2$, [Au$_2$Cl$_2$(μ$_2$-POP)], and [Au$_2$(μ$_2$-POP)$_2$](OTf)$_2$. The photo-optical properties of the PPO- and POP-type transition metal complexes are investigated experimentally using photo-luminescence spectroscopy, whereby the presence of metallophillic interactions was found to play a crucial role. The dinuclear copper complex [Cu$_2$(MeCN)$_3$(μ$_2$-POP)$_2$](PF$_6$)$_2$ shows a very interesting thermochromic behavior and intense photo-luminescence with remarkable phosphoresence lifetimes at 77 K, which can probably be attributed to short intramolecular Cu–Cu distances

Solvatomorphism of Moxidectin

The solvatomorphism of the anthelmintic drug moxidectin is investigated, and a new solvatomorph with nitromethane is reported. Moreover, the hitherto unknown crystal structures of the solvatomorphs with ethanol and 2-propanol are reported and discussed. The thermal characterization of these solvatomorphs through variable-temperature powder X-ray diffraction analysis (VT-PXRD) is also described, providing new insights into the crystallochemistry of this active pharmaceutical ingredient

CO2 Adsorption in a Robust Iron(III) Pyrazolate-Based MOF: Molecular-Level Details and Frameworks Dynamics From Powder X-ray Diffraction Adsorption Isotherms

Understanding adsorption processes at the molecular level, with multi-technique approaches, is nowadays at the frontier of porous materials research. In this work it is shown that with a proper data treatment, in situ high-resolution powder X-ray diffraction (HR-PXRD) at variable temperature and gas pressure can reveal atomic details of the accommodation sites, the framework dynamics as well as thermodynamic information (isosteric heat of adsorption) of the CO2 adsorption process in the robust iron(III) pyrazolate-based MOF Fe2(BDP)3 [H2BDP = 1,4-bis(1H-pyrazol-4-yl)benzene]. Highly reliable "HR-PXRD adsorption isotherms" can be constructed from occupancy values of CO2 molecules. The "HR-PXRD adsorption isotherms" accurately match the results of conventional static and dynamic gas sorption experiments and Monte Carlo simulations. These results are indicative of the impact of the molecular-level behavior on the bulk properties of the system under study and of the potential of the presented multi-technique approach to understand adsorption processes in metal-organic frameworks

Correction: Facile synthesis of <i>cyclo</i>-(P₄^<i>t</i>Bu₃)-containing oligo- and pnictaphosphanes

Correction for 'Facile synthesis of cyclo-(P4tBu3)-containing oligo- and pnictaphosphanes' by Volker Jens Eilrich et al., Dalton Trans., 2021, 50, 14144–14155, DOI: 10.1039/D1DT02639A

Solvatomorphism of Moxidectin

The solvatomorphism of the anthelmintic drug moxidectin is investigated, and a new solvatomorph with nitromethane is reported. Moreover, the hitherto unknown crystal structures of the solvatomorphs with ethanol and 2-propanol are reported and discussed. The thermal characterization of these solvatomorphs through variable-temperature powder X-ray diffraction analysis (VT-PXRD) is also described, providing new insights into the crystallochemistry of this active pharmaceutical ingredient

Methanol Sensing by a Luminescent Zinc(II)‐Based Metal−Organic Framework

A luminescent zinc-based metal-organic framework (MOF; 1) was synthesized from a highly conjugated tridentate ligand, 1,3,5-tris[(1E)-2′-(4′′-benzoic acid)vinyl]benzene. X-ray single crystal analysis reveals the organization of 1 in a three-dimensional porous framework. Thermogravimetric analysis shows that 1 has a good thermal stability, and resists decomposition up to 420 °C. The removal of the solvent molecules from the cavities leads to a temporary loss of crystallinity, which can be regained by heating the MOF in diethylformamide, the solvent used for the synthesis, as shown by powder X-ray diffraction. In addition, 1 shows luminescent features influenced by the chemical environment, making it suitable as optical sensor. Detection of methanol with a turn-on effect was possible in low concentration in mixtures with water (50 μL/3 mL and 10 μL/3 mL) and as vapor

Methanol Sensing by a Luminescent Zinc(II)-Based Metal−Organic Framework

A luminescent zinc-based metal-organic framework (MOF; 1) was synthesized from a highly conjugated tridentate ligand, 1,3,5-tris[(1E)-2′-(4′′-benzoic acid)vinyl]benzene. X-ray single crystal analysis reveals the organization of 1 in a three-dimensional porous framework. Thermogravimetric analysis shows that 1 has a good thermal stability, and resists decomposition up to 420 °C. The removal of the solvent molecules from the cavities leads to a temporary loss of crystallinity, which can be regained by heating the MOF in diethylformamide, the solvent used for the synthesis, as shown by powder X-ray diffraction. In addition, 1 shows luminescent features influenced by the chemical environment, making it suitable as optical sensor. Detection of methanol with a turn-on effect was possible in low concentration in mixtures with water (50 μL/3 mL and 10 μL/3 mL) and as vapor

Versatile Coordination Modes of Triphospha-1,4-pentadiene-2,4-diamine

1,3,5-Triphospha-1,4-pentadiene-2,4-diamine reacts with [M­(CO)₄L] (M = Mo, L = nbd (norbornadiene); M = W, L = 2 CH₃CN) to give the chelate complexes [M­(CO)₄(PMes­{C­(NHCy)­PMes}₂-κ<i>P</i>¹<i>,P</i>³)]. In contrast, an unusual intramolecular rearrangement occurred with [Cu­(CH₃CN)₄]­PF₆ leading to the dimeric copper­(I) complex [Cu­(CNCy)­{PHMesP­MesC­(NHCy)­PMes-κ<i>P</i>¹<i>,P</i>³}]₂(PF₆)₂. The mechanism of the rearrangement was supported by quantum-mechanical calculations. The transition-metal complexes were characterized by multinuclear NMR spectroscopy, mass spectrometry, infrared spectroscopy, and X-ray crystallography

Facile synthesis of a nickel(0) phosphine complex at ambient temperature.

The reaction of the bis(methoxy)-2-pyridyl-phosphine (MeO)2P(2-py) (1) with [Ni(MeCN)6](BF4)2 leads to the unexpected single-step reduction of NiII and the formation of a tetrahedral nickel(0) complex [{(MeO)2P(2-py-H)}2{(MeO)2P(2-py)}2Ni](BF4)2 (2). The redox activity is probably induced by the decomposition of the tetrafluoroborate anion; NMR spectroscopic studies point towards a fluoride-assisted oxidation of the 2-pyridyl-phosphine ligand, with associated reduction of the metal

EHDTA: a green approach to efficient Ln3+-chelators

: The rich coordination chemistry of lanthanoid ions (Ln3+) is currently exploited in a vast and continuously expanding array of applications. Chelating agents are central in the development of Ln3+-complexes and in tuning their physical and chemical properties. Most chelators for Ln3+-complexation are derived from the macrocyclic DOTA or from linear DTPA platforms, both of which arise from fossil-based starting materials. Herein, we report a green and efficient approach to a chelating agent (EHDTA), derived from cheap and largely available furfurylamine. The oxygenated heterocycle of the latter is converted to a stereochemically defined and rigid heptadentate chelator, which shows good affinity towards Ln3+ ions. A combination of NMR, relaxometric, potentiometric and spectrophotometric techniques allows us to shed light on the interesting coordination chemistry of Ln3+-EHDTA complexes, unveiling a promising ligand for the chelation of this important family of metal ions