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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]

There is a growing interest in developing paramagnetic nanoparticles as responsive magnetic resonance imaging (MRI) contrast agents, which feature switchable T 1 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 T 1 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 T 1 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" T 1 contrast. Using peptide-induced liposomal gadopentetic acid (Gd 3+ -DTPA) release and redox-sensitive manganese oxide (MnO 2 ) nanoparticles as a demonstration of generality, this method successfully evaluates the T 1 shortening of water protons caused by liposomal Gd 3+ -DTPA release and Mn 2+ formation from MnO 2 reduction. Furthermore, the NMR measurement is highly correlated to T 1 -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 T 1 contrast systems., (© 2024 Wiley‐VCH GmbH.)

A structurally precise hydride-containing Pt-doped Cu-rich nanocluster [PtH 2 Cu 14 {S 2 P(O i Pr) 2 } 6 (CCPh) 6 ] (1) has been synthesized. It consists of a bicapped icosahedral Cu 14 cage that encapsulates a linear PtH 2 unit. Upon the addition of two equivalents of CF 3 COOH to 1, two hydrido clusters are isolated. These clusters are [PtHCu 11 {S 2 P(O i Pr) 2 } 6 (CCPh) 4 ] (2), which is a vertex-missing Cu 11 cuboctahedron encaging a PtH moiety, and [PtH 2 Cu 11 {S 2 P(O i Pr) 2 } 6 (CCPh) 3 ] (3), a distorted 3,3,4,4,4-pentacapped trigonal prismatic Cu 11 cage enclosing a PtH 2 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 H 2 SO 4 . 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., (© 2023 Wiley-VCH GmbH.)

Three hitherto unknown eight-electron rhodium/silver alloy nanoclusters, [RhAg 21 {S 2 P(O n Pr) 2 } 12 ] ( 1 ), [RhHAg 20 {S 2 P(O n Pr) 2 } 12 ] ( 2 ), and [RhH 2 Ag 19 {S 2 P(O n Pr) 2 } 12 ] ( 3 ), have been isolated and fully characterized. Cluster 1 contains a regular Rh@Ag 12 icosahedral core, whereas 2 and 3 exhibit distorted RhH@Ag 12 and RhH 2 @Ag 12 icosahedral cores. The single-crystal neutron structure of 2 located the encapsulated hydride at the center of an enlarged RhAg 3 tetrahedron. A similar position was found by neutron diffraction for one of the hydrides in 3 , whereas the other hydride is trigonally coordinated to Rh and an elongated Ag-Ag edge. The solid-state structures of 1 - 3 possess C 1 symmetry due to the asymmetric arrangement of the surrounding capping Ag atoms. Our investigation shows that the insertion of one hydride dopant provokes the elimination of one capping silver atom on the cluster surface, resulting in the general formula [RhH x @Ag 21- x {S 2 P(O n Pr) 2 } 12 ] ( x = 0-2), which maintains the same number of cluster electrons as well as neutral charge. Clusters 1 - 3 exhibit an intense emission band in the NIR region. Contrarily to their PdAg 21 and PdHAg 20 relatives, the 4d orbitals of the encapsulated heterometal are somewhat involved in the optical processes.

The first 8-electron Pd/Ag superatomic alloys with an interstitial hydride [PdHAg 19 (dtp) 12 ] (dtp=S 2 P(O i Pr) 2 - ) 1 and [PdHAg 20 (dtp) 12 ] + 2 are reported. The targeted addition of a single Ag atom to 1 is achieved by the reaction of one equivalent of trifluoroacetic acid, resulting in the formation of 2 in 55 % yield. Further modification of the shell results in the formation of [PdAg 21 (dtp) 12 ] + 3 via an internal redox reaction, with the system retaining an 8-electron superatomic configuration. The interstitial hydride in 1 and 2 contributes its 1s 1 electron to the superatomic electron count and occupies a PdAg 3 tetrahedron. The distributions of isomers corresponding to different dispositions of the outer capping Ag atoms are investigated by multinuclear VT NMR spectroscopy. The emissive state of 3 has a lifetime of 200 μs (λ ex =448; λ em =842), while 1 and 2 are non-emissive. The catalytic reduction of 4-nitrophenol is demonstrated with 1-3 at room temperature., (© 2023 Wiley-VCH GmbH.)

The structural diversity of polycyclic aromatic hydrocarbons (PAHs) offers exciting opportunities for their applications. Yet, selective synthesis of such conjugated networks poses a formidable challenge. Compared to the prominence of transition-metal-catalyzed cross-coupling and oxidative Scholl reactions, cationic rearrangement in the synthesis of polycyclic aromatic hydrocarbon is an underexplored subject. In this study, we reveal that cationic intermediate generated from epoxy dibenzocycloheptanol can be transformed into acenes, azulene-embedded PAHs, and dibenzocycloheptanone derivatives. Reactive patterns, including Meinwald rearrangement, Nazarov cyclization, transannular aryl migration, and transannular Friedel-Crafts cyclization were identified. Both substrate structures and reaction temperature affect the reaction pathways in predictable and manageable manners. A mechanistic scheme was postulated as the working model to guide the reactivity for further application. Substrates containing heterocyclic and ferrocenyl groups exhibit similar reactivity profiles. The inquiry culminates in the selective synthesis of 5, 7, 12, 14-tetrasubstituted C 2 h and C 2 v pentacene derivatives. Our results demonstrate that polycyclic aromatic hydrocarbons can be selectively prepared with this cation-initiated strategy by methodically tuning the reactivity., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

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 Cu I dihydride template [Cu 11 H 2 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 3 ] (H 2 Cu 11 ) generates surprisingly three very different compounds, namely [CuH 2 Cu 11 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 3 ] + (1), [AgH 2 Cu 14 {S 2 P(O i Pr) 2 } 6 ((C≡CPh) 6 ] + (2), and [AuCu 11 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 3 Cl] (3). Compounds 1 and 2 are both M I species and maintain the same number of hydride ligands as their H 2 Cu 11 precursor. Neutron diffraction revealed the first time a trigonal-pyramidal hydride coordination mode in the AgCu 3 environment of 2. 3 has no hydride and exhibits a mixed-valent [AuCu 11 ] 10+ metal core, making it a two-electron superatom., (© 2021 Wiley-VCH GmbH.)