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There is a growing interest in developing paramagnetic nanoparticles as responsive magnetic resonance imaging (MRI) contrast agents, which feature switchable T1 image contrast of water protons upon biochemical cues for better discerning diseases. However, performing an MRI is pragmatically limited by its cost and availability. Hence, a facile, routine method for measuring the T1 contrast is highly desired in early‐stage development. This work presents a single‐point inversion recovery (IR) nuclear magnetic resonance (NMR) method that can rapidly evaluate T1 contrast change by employing a single, optimized IR pulse sequence that minimizes water signal for "off‐state" nanoparticles and allows for sensitively measuring the signal change with "switch‐on" T1 contrast. Using peptide‐induced liposomal gadopentetic acid (Gd3+‐DTPA) release and redox‐sensitive manganese oxide (MnO2) nanoparticles as a demonstration of generality, this method successfully evaluates the T1 shortening of water protons caused by liposomal Gd3+‐DTPA release and Mn2+ formation from MnO2 reduction. Furthermore, the NMR measurement is highly correlated to T1‐weighted MRI scans, suggesting its feasibility to predict the MRI results at the same field strength. This NMR method can be a low‐cost, time‐saving alternative for pre‐MRI evaluation for a diversity of responsive T1 contrast systems. [ABSTRACT FROM AUTHOR]

A structurally precise hydride‐containing Pt‐doped Cu‐rich nanocluster [PtH2Cu14{S2P(OiPr)2}6(CCPh)6] (1) has been synthesized. It consists of a bicapped icosahedral Cu14 cage that encapsulates a linear PtH2 unit. Upon the addition of two equivalents of CF3COOH to 1, two hydrido clusters are isolated. These clusters are [PtHCu11{S2P(OiPr)2}6(CCPh)4] (2), which is a vertex‐missing Cu11 cuboctahedron encaging a PtH moiety, and [PtH2Cu11{S2P(OiPr)2}6(CCPh)3] (3), a distorted 3,3,4,4,4‐pentacapped trigonal prismatic Cu11 cage enclosing a PtH2 unit. The electronic structure of 2, analyzed by Density Functional Theory, is a 2e superatom. The electrocatalytic activities of 1–3 for hydrogen evolution reaction (HER) were compared. Notably, Cluster 2 exhibited an exceptionally excellent HER activity within metal nanoclusters, with an onset potential of −0.03 V (at 10 mA cm−2), a Tafel slope of 39 mV dec−1, and consistent HER activity throughout 3000 cycles in 0.5 M H2SO4. Our study suggests that the accessible central Pt site plays a crucial role in the remarkable HER activity and may provide valuable insights for establishing correlations between catalyst structure and HER activity. [ABSTRACT FROM AUTHOR]

Chemical components in the hexane‐extract mixture from Phalaenopsis leaves were isolated and identified during the spike induction process. Several lipophilic components in the hexane‐extract mixture were isolated and identified as oleic acid, 1,2‐O‐dilinolenoyl‐MGDG, 1‐O‐linolenoyl‐2‐O‐linoleoyl‐MGDG, and α‐tocopherol by HPLC and NMR techniques. It is noteworthy that only one isomer of α‐tocopherol was isolated from Phalaenopsis leaves based on NMR spectra analysis. MGDG have a great potential to be a control factor in the regulation of spike process of Phalaenopsis. It is the first time to identify the chemical MGDG related to temperature‐controlled process of Phalaenopsis. These components have hydrophilic and hydrophobic moieties in the same molecule to act as potential amphiphiles. The use of the entire mixed hexane extract to form liposomes containing the dmbpyPtCl2 complex greatly enhanced the reactivity of the complex for inhibiting E. coli growth compared with the use of a single amphiphile. [ABSTRACT FROM AUTHOR]

In sharp contrast to surface hydrides, reactivities of interstitial hydrides are difficult to explore. When treated with a metal ion (Cu+, Ag+, and Au+), the stable CuI dihydride template [Cu11H2{S2P(OiPr)2}6(C≡CPh)3] (H2Cu11) generates surprisingly three very different compounds, namely [CuH2Cu11{S2P(OiPr)2}6(C≡CPh)3]+ (1), [AgH2Cu14{S2P(OiPr)2}6((C≡CPh)6]+ (2), and [AuCu11{S2P(OiPr)2}6(C≡CPh)3Cl] (3). Compounds 1 and 2 are both MI species and maintain the same number of hydride ligands as their H2Cu11 precursor. Neutron diffraction revealed the first time a trigonal‐pyramidal hydride coordination mode in the AgCu3 environment of 2. 3 has no hydride and exhibits a mixed‐valent [AuCu11]10+ metal core, making it a two‐electron superatom. [ABSTRACT FROM AUTHOR]

In our attempts to identify probable intermediates in the preparation of anionic silver hydride cluster [Ag8(H){S2CC(CN)2}6]5− under the condition of excess NaBH4, we isolated and analyzed a new cluster compound, namely, [Bu4N]6[Ag7(H){S2CC(CN)2}6]. We report here the synthesis, crystal structure, characterizations by various spectroscopic (UV–Vis, IR, multinuclear NMR, elemental analyses) techniques and the luminescent properties of this cluster. Its X-ray crystal structure reveals that the cluster contains a distorted; tricapped tetrahedral silver core enclosed an interstitial hydride anion and is surrounded by six 1,1-dicyanoethylene-2,2-dithiolate ([S2CC(CN)2]2−, i-MNT) ligands. The presence of hydride inside the heptanuclear silver cluster is unequivocally certified by both 1H and 109Ag NMR spectroscopies. The title compound represents the first atomic precisely anionic Ag7-H skeleton with a non-disordered, tricapped tetrahedral silver framework. [ABSTRACT FROM AUTHOR]

Reaction of Mo2(O2CCH3)2(DMepyF)2 (HDMepyF=N,N′-di(6-methyl-2-pyridyl)formamidine) with HBF4 in CH2Cl2/CH3CN afforded the complex trans-[Mo2(H2DMepyF)2(CH3CN)4](BF4)6 (1), which crystallized in two forms, trans-[Mo2(H2DMepyF)2(CH3CN)4](ax-CH3CN)2(BF 4)6 · 2CH3CN (1a), and trans- [Mo2(H2DMepyF)2(CH3CN)4](ax-BF4) 2(BF4)4 · 2CH3CN (1b). The molecular structures of complexes (1) consist of two quadruply bonded molybdenum atoms, which are spanned by two trans-bridging formamidinate ligands and coordinated by four trans-CH3CN. Each H2DMepyF+ ligand adopts an s-cis,s-cis- conformation. The difference between 1a and 1b is that complex 1a contains two CH3CN molecules as axial ligands, while 1b contains two BF4− anions as axial ligands. Complex 1 is the first dimolybdenum complex containing a pair of trans bridging ligands and two pairs of trans-CH3CN ligands. [Copyright &y& Elsevier]