One-Electron (2c/1e) Tin···Tin Bond Stabilized by ortho-Phenylenediamido Ligands.

Odd-electron bonds, i.e., the two-center, three-electron (2c/3e), or one-electron (2c/1e) bonds, have attracted tremendous interest owing to their novel bonding nature and radical properties. Herein, complex [K(THF)6][LSn:···Sn:L] (1), featuring the first and unsupported 2c/1e Sn···Sn σ-bond with a long distance (3.2155(9) Å), was synthesized by reduction of stannylene [LSn:] (L = N,N-dpp-o-phenylene diamide) with KC8. The one-electron Sn-Sn bond in 1 was confirmed by the crystal structure, DFT calculations, EPR spectroscopy, and reactivity studies. This compound can be viewed as a stabilized radical by delocalizing to two metal centers and can readily mediate radical reactions such as C-C coupling of benzaldehyde.

Vanadium-Catalyzed Dinitrogen Reduction to Ammonia via a [V]═NNH2 Intermediate.

The catalytic transformation of N2 to NH3 by transition metal complexes is of great interest and importance but has remained a challenge to date. Despite the essential role of vanadium in biological N2 fixation, well-defined vanadium complexes that can catalyze the conversion of N2 to NH3 are scarce. In particular, a V(NxHy) intermediate derived from proton/electron transfer reactions of coordinated N2 remains unknown. Here, we report a dinitrogen-bridged divanadium complex bearing POCOP (2,6-(tBu2PO)2-C6H3) pincer and aryloxy ligands, which can serve as a catalyst for the reduction of N2 to NH3 and N2H4. Low-temperature protonation and reduction of the dinitrogen complex afforded the first structurally characterized neutral metal hydrazido(2-) species ([V]═NNH2), which mediated 15N2 conversion to 15NH3, indicating that it is a plausible intermediate of the catalysis. DFT calculations showed that the vanadium hydrazido complex [V]═NNH2 possessed a N-H bond dissociation free energy (BDFEN-H) of as high as 59.1 kcal/mol. The protonation of a vanadium amide complex ([V]-NH2) with [Ph2NH2][OTf] resulted in the release of NH3 and the formation of a vanadium triflate complex, which upon reduction under N2 afforded the vanadium dinitrogen complex. These transformations model the final steps of a vanadium-catalyzed N2 reduction cycle. Both experimental and theoretical studies suggest that the catalytic reaction may proceed via a distal pathway to liberate NH3. These findings provide unprecedented insights into the mechanism of N2 reduction related to FeV nitrogenase.

Automatic P-Phase-Onset-Time-Picking Method of Microseismic Monitoring Signal of Underground Mine Based on Noise Reduction and Multiple Detection Indexes.

The underground pressure disaster caused by the exploitation of deep mineral resources has become a major hidden danger restricting the safe production of mines. Microseismic monitoring technology is a universally recognized means of underground pressure monitoring and early warning. In this paper, the wavelet coefficient threshold denoising method in the time-frequency domain, STA/LTA method, AIC method, and skew and kurtosis method are studied, and the automatic P-phase-onset-time-picking model based on noise reduction and multiple detection indexes is established. Through the effect analysis of microseismic signals collected by microseismic monitoring system of coral Tungsten Mine in Guangxi, automatic P-phase onset time picking is realized, the reliability of the P-phase-onset-time-picking method proposed in this paper based on noise reduction and multiple detection indexes is verified. The picking accuracy can still be guaranteed under the severe signal interference of background noise, power frequency interference and manual activity in the underground mine, which is of great significance to the data processing and analysis of microseismic monitoring.

Allosteric inhibition of SHP2 phosphatase inhibits cancers driven by receptor tyrosine kinases.

The non-receptor protein tyrosine phosphatase SHP2, encoded by PTPN11, has an important role in signal transduction downstream of growth factor receptor signalling and was the first reported oncogenic tyrosine phosphatase. Activating mutations of SHP2 have been associated with developmental pathologies such as Noonan syndrome and are found in multiple cancer types, including leukaemia, lung and breast cancer and neuroblastoma. SHP2 is ubiquitously expressed and regulates cell survival and proliferation primarily through activation of the RAS­ERK signalling pathway. It is also a key mediator of the programmed cell death 1 (PD-1) and B- and T-lymphocyte attenuator (BTLA) immune checkpoint pathways. Reduction of SHP2 activity suppresses tumour cell growth and is a potential target of cancer therapy. Here we report the discovery of a highly potent (IC50 = 0.071 µM), selective and orally bioavailable small-molecule SHP2 inhibitor, SHP099, that stabilizes SHP2 in an auto-inhibited conformation. SHP099 concurrently binds to the interface of the N-terminal SH2, C-terminal SH2, and protein tyrosine phosphatase domains, thus inhibiting SHP2 activity through an allosteric mechanism. SHP099 suppresses RAS­ERK signalling to inhibit the proliferation of receptor-tyrosine-kinase-driven human cancer cells in vitro and is efficacious in mouse tumour xenograft models. Together, these data demonstrate that pharmacological inhibition of SHP2 is a valid therapeutic approach for the treatment of cancers.

Sinensetin Attenuates Amyloid Beta25-35-Induced Oxidative Stress, Inflammation, and Apoptosis in SH-SY5Y Cells Through the TLR4/NF-κB Signaling Pathway.

Sinensetin (SIN) is an important active compound that exists widely in citrus plants, and has been reported to exhibit various pharmacological properties, including anti-oxidative, anti-inflammatory, and anti-tumor. This study was designed to examine whether SIN can protect against amyloid beta (Aß)-induced neurotoxicity and to elucidate the underlying mechanism. Our results showed that pretreatment with SIN for 1 h, followed by co-treatment with Aß plus SIN for 24 h, attenuated Aß25-35-induced cell viability reduction, oxidative stress, inflammation, and apoptosis in a dose-dependent manner. Aß25-35-induced upregulation of Toll-like receptor 4 (TLR4) expression and nuclear translocation of nuclear factor-kappaB (NF-κB) p65 subunit were inhibited by pretreatment with SIN. Furthermore, the protective effect of SIN was abrogated by TLR4 overexpression. Hence, our data suggested that SIN attenuated Aß25-35-induced neurotoxicity through the TLR4/NF-κB pathway.

Moschamindole induces glioma cell apoptosis by blocking Mia40-dependent mitochondrial intermembrane space assembly and oxidative respiration.

Glioblastoma multiforme (GBM) is the most frequent, lethal, and aggressive tumor of the central nervous system in adults. In this study, we found for the first time that moschamindole (MCD), a rare phenolic amide with 8/6/6/5/5 rings, is a major bioactive constituent derived from Phragmites communis Trin (Poaceae) that exhibits a potential cytotoxic effect on both TMZ-resistant GBM cell lines and xenograft models. MCD-induced intrinsic apoptosis signals and mitochondrial dysfunction were confirmed by cell cycle arrest, caspase-3/7 activation, and membrane potential depolarization. Furthermore, investigations exploring the mechanism showed that MCD specifically inhibits Mia40-mediated oxidative folding of mitochondrial intermembrane space (IMS) proteins via PCR assay and immunoblot analysis. MCD relies on its positive charge to associate with mitochondrial oxidative respiration, thus blocking energy metabolism and inducing apoptosis. Overexpression and upregulation of Mia40 were proven to reverse MCD-induced apoptosis and were correlated with the chemoresistance of GBM in vitro and in vivo, respectively. Taken together, our study demonstrates that Mia40 is a potential target of the chemoresistance of glioblastoma and suggests that MCD might be a potential agent for the individualized treatment of chemoresistant GBM based on mitochondrial metabolic characteristics and Mia40 expression.

Multifunctionalization of Unactivated Cyclic Ketones via an Electrochemical Process: Access to Cyclic α-Enaminones.

The multifunctionalization of unactivated cyclic ketones was developed via an electrochemically intermolecular α-amination under metal-free conditions. The reaction can be carried out smoothly with a broad scope of the aromatic amines substrates under mild conditions, affording a variety of α-enaminones with good to excellent yields in one step.

Radical-Facilitated Green Synthesis of Highly Ordered Mesoporous Silica Materials.

In the hydrothermal synthesis of highly ordered mesoporous silica material SBA-15, strong acid is typically required to catalyze the hydrolysis and condensation of silica species. Meanwhile, under strongly acidic conditions, the transition metal ions, e.g., iron ions, are difficult to incorporate into SBA-15 because of the facile dissociation of Fe-O-Si bonds. Here, we demonstrate an acid-free green synthetic strategy for the synthesis of highly ordered mesoporous SBA-15 and Fe-SBA-15 with the assistance of hydroxyl free radicals that are generated by physical or chemical methods. The prepared materials exhibit a large specific surface area compared to the counterparts prepared by conventional method under acidic conditions. Moreover, Fe-SBA-15 shows high metal loading efficiency as over 50%. Density functional theory calculations suggest that the hydroxyl free radicals exhibit higher catalytic activity than H+ ions for the hydrolysis of tetraethyl orthosilicate. This radical-facilitated synthesis approach overcomes the challenge to the direct synthesis of highly ordered SBA-15 and Fe-SBA-15 without adding any acid, providing a facile and environmentally friendly route for future large-scale production of ordered mesoporous materials.

A Stratified Algorithm for Skull Base Reconstruction With Endoscopic Endonasal Approach.

The authors presented our institutional experience with skull base reconstruction techniques and developed a stratified algorithm for different causes of cerebrospinal fluid (CSF) leak. This is a retrospective review of patients who were diagnosed as CSF leak treated with skull base reconstruction or who underwent endoscopic transsphenoidal surgery for sellar and parasellar lesions at our department from August 2012 to April 2017. The authors totally identified 57 (59 operations in total) patients who were divided into 3 groups according to the causes of CSF leak and different reconstruction techniques. All patients underwent skull base reconstruction with specific focus on diagnosis, reconstruction techniques and strategies, and clinical outcome. The reconstruction technique we adopted was the classical multiple-layer technique, as known as "sandwich" technique, with combination of fat tissue, septal bone, autologous fascia lata, artificial dura, and nasoseptal flap (NSF). The NSF was selectively harvested for large defects according to our protocol. The reconstruction failure rate is 4.4% (2 of 45) in patients underwent endoscopic surgery for sellar and parasellar lesions. Reconstruction for postoperative iatrogenic, traumatic, and spontaneous CSF leak achieved 100% success rate; 54.2% (32 of 59) operations were done with "sandwich" plus NSF. The overall failure rate of all reconstructions was 3.4% (2 of 59). A stratified approach with multiple-layer technique and NSF is reliable for skull base reconstruction.

A Chiral Ligand Assembly That Confers One-Electron O2 Reduction Activity for a Cu2+ -Selective Metallohydrogel.

The design of functional metallohydrogels is attractive but challenging. A rational approach is introduced for designing functional metallohydrogels using chiral ligands, a phenylalanine derivative with a pyridyl group (l/d-PF). Intriguingly, the as-prepared metallohydrogel exhibits excellent O2 binding and activating properties. Insights into the O2 binding pathway reveals the presence of a novel [(l+d)-PF-Cu3+ -O2- ] species, which can efficiently reduce ferric cytochrome c with the reactive O2- by receiving an electron from reductant ascorbic acid. This study provides helpful instructions for developing new artificial systems with specific functions through the effective combination of chiral ligands with metal ions.

Electrocatalytic C-H/N-H Coupling of 2'-Aminoacetophenones for the Synthesis of Isatins.

2'-Aminoacetophenones undergo a C(sp3)-H oxidation followed by intramolecular C-N bond formation by virtue of a simple electrochemical oxidation in the presence of n-Bu4NI, providing various isatins with moderate to good yields. The reaction intermediates were detected, and a radical-based pathway was proposed.

Direct Evidence for Neutral N-Pyrazolyl Radicals: Paddlewheel Dibismuthanes Bearing Pyrazolato Ligands with Very Short Bi-Bi Single Bonds.

Neutral N-pyrazolyl radicals [3,5-R2pz]• as reactive intermediates were generated by one-electron oxidization of the corresponding 3,5-disubstituted pyrazolato anions [3,5-R2pz]- (R = tBu, Ph) with BiCl3 and trapped by the use of 5,5-dimethyl-1-pyrroline-N-oxide as a spin trap, which was confirmed by electron paramagnetic resonance spectral analysis. With dimerization of the postulated pyrazolato low-valent BiII radical species, two novel paddlewheel pyrazolatodibismuthanes [L2(Bi-Bi)L2] [L = η1,η1-3,5-R2pz; R = tBu (5α, 5ß, and 5γ), Ph (6)] were isolated and structurally characterized.

Endoscopic Versus Microscopic Transsphenoidal Surgery for Pituitary Tumors.

BACKGROUND: To compare the clinical outcomes and complications of 247 pituitary tumor patients managed by endoscopic and microscopic approaches in our hospital. METHODS: The authors performed a retrospective review of 100 pituitary tumor patients treated by endoscopic endonasal transsphenoidal surgery (ETS) and 147 patients treated by microscopic transsphenoidal surgery (MTS) at our center from January 2007 to July 2014. The tumors were stratified by Knosp classification and modified Hardy classification, and tumor gross total resection (GTR)/remission rate, visual improvement rate, complications, operation time, intraoperative bleeding and length of hospital stay were compared between ETS and MTS. RESULTS: The GTR rate decreased with increasing Knosp grades for both ETS and MTS, with the rates of 93.3%, 87.5%, 71.4%, 58.8% for ETS and 82.8%, 92.0%, 70.7%, 36.0% for MTS in resecting Knosp grades 0, I, II, and III tumors, respectively. The visual improvement rates increased with increasing Hardy grades, which was 66.7% and 45.5% for Hardy grade B lesion, 72.2% and 71.4% for grade C lesion, and 88.9% and 78.9% for grade D lesion treated by ETS and MTS, respectively. No significant differences were observed for GTR rate, visual outcome and complication rate between ETS and MTS, while ETS resulted in more intraoperative blood loss, longer operative time, and shorter hospital stay than MTS. CONCLUSIONS: These data conclude that, compared with MTS, ETS needs longer operation time and results in more intraoperative blood loss, but appears to achieve higher GTR rate for Knosp grade III pituitary tumors.

Mono- and Dinuclear Heteroleptic Cobalt Complexes with α-Diimine and Polyarene Ligands.

Reactions of the dimeric cobalt complex [(L(-) Co)2 ] (1, L=[(2,6-iPr2 C6 H3 )NC(Me)]2 ) with polyarenes afforded a series of mononuclear and dinuclear complexes: [LCo(η(4) -anthracene)] (2), [LCo(µ-η(4) :η(4) -naphthalene)CoL] (3), and [LCo(µ-η(4) :η(4) -phenanthrene)CoL] (4). The pyrene complexes [{Na2 (Et2 O)2 }{LCo(µ-η(3) :η(3) -pyrene)CoL}] (5) and [{Na2 (Et2 O)3 }{LCo(η(3) -pyrene)}] (6) were obtained by treating precursor 1 with pyrene followed by reduction with Na metal. These complexes contain three potential redox active centers: the cobalt metal and both α-diimine and polyarene ligands. Through a combination of X-ray crystallography, EPR spectroscopy, magnetic susceptibility measurement, and DFT computations, the electronic configurations of these complexes were studied. It was determined that complexes 2-4 have a high-spin Co(I) center coupled with a radical α-diimine ligand and a neutral polyarene ligand. Whereas, the ligand L in complexes 5 and 6 has been further reduced to the dianion, the cobalt remains in a formal (I) oxidation state, and the pyrene molecule is either neutral or monoanionic.

Selective inhibition of Ezh2 by a small molecule inhibitor blocks tumor cells proliferation.

Ezh2 (Enhancer of zeste homolog 2) protein is the enzymatic component of the Polycomb repressive complex 2 (PRC2), which represses gene expression by methylating lysine 27 of histone H3 (H3K27) and regulates cell proliferation and differentiation during embryonic development. Recently, hot-spot mutations of Ezh2 were identified in diffused large B-cell lymphomas and follicular lymphomas. To investigate if tumor growth is dependent on the enzymatic activity of Ezh2, we developed a potent and selective small molecule inhibitor, EI1, which inhibits the enzymatic activity of Ezh2 through direct binding to the enzyme and competing with the methyl group donor S-Adenosyl methionine. EI1-treated cells exhibit genome-wide loss of H3K27 methylation and activation of PRC2 target genes. Furthermore, inhibition of Ezh2 by EI1 in diffused large B-cell lymphomas cells carrying the Y641 mutations results in decreased proliferation, cell cycle arrest, and apoptosis. These results provide strong validation of Ezh2 as a potential therapeutic target for the treatment of cancer.

Differential proteomic analysis of grapevine leaves by iTRAQ reveals responses to heat stress and subsequent recovery.

BACKGROUND: High temperature is a major environmental factor limiting grape yield and affecting berry quality. Thermotolerance includes the direct response to heat stress and the ability to recover from heat stress. To better understand the mechanism of the thermotolerance of Vitis, we combined a physiological analysis with iTRAQ-based proteomics of Vitis vinifera cv Cabernet Sauvignon, subjected to 43°C for 6 h, and then followed by recovery at 25/18°C. RESULTS: High temperature increased the concentrations of TBARS and inhibited electronic transport in photosynthesis apparatus, indicating that grape leaves were damaged by heat stress. However, these physiological changes rapidly returned to control levels during the subsequent recovery phase from heat stress. One hundred and seventy-four proteins were differentially expressed under heat stress and/or during the recovery phase, in comparison to unstressed controls, respectively. Stress and recovery conditions shared 42 proteins, while 113 and 103 proteins were respectively identified under heat stress and recovery conditions alone. Based on MapMan ontology, functional categories for these dysregulated proteins included mainly photosynthesis (about 20%), proteins (13%), and stress (8%). The subcellular localization using TargetP showed most proteins were located in the chloroplasts (34%), secretory pathways (8%) and mitochondrion (3%). CONCLUSION: On the basis of these findings, we proposed that some proteins related to electron transport chain of photosynthesis, antioxidant enzymes, HSPs and other stress response proteins, and glycolysis may play key roles in enhancing grapevine adaptation to and recovery capacity from heat stress. These results provide a better understanding of the proteins involved in, and mechanisms of thermotolerance in grapevines.

Genetic diversity and prevalence of emerging Rickettsiales in Yunnan Province: a large-scale study.

BACKGROUND: Rickettsia and related diseases have been identified as significant global public health threats. This study involved comprehensive field and systematic investigations of various rickettsial organisms in Yunnan Province. METHODS: Between May 18, 2011 and November 23, 2020, field investigations were conducted across 42 counties in Yunnan Province, China, encompassing small mammals, livestock, and ticks. Preliminary screenings for Rickettsiales involved amplifying the 16S rRNA genes, along with additional genus- or species-specific genes, which were subsequently confirmed through sequencing results. Sequence comparisons were carried out using the Basic Local Alignment Search Tool (BLAST). Phylogenetic relationships were analyzed using the default parameters in the Molecular Evolutionary Genetics Analysis (MEGA) program. The chi-squared test was used to assess the diversities and component ratios of rickettsial agents across various parameters. RESULTS: A total of 7964 samples were collected from small mammals, livestock, and ticks through Yunnan Province and submitted for screening for rickettsial organisms. Sixteen rickettsial species from the genera Rickettsia, Anaplasma, Ehrlichia, Neoehrlichia, and Wolbachia were detected, with an overall prevalence of 14.72%. Among these, 11 species were identified as pathogens or potential pathogens to humans and livestock. Specifically, 10 rickettsial organisms were widely found in 42.11% (24 out of 57) of small mammal species. High prevalence was observed in Dremomys samples at 5.60%, in samples from regions with latitudes above 4000 m or alpine meadows, and in those obtained from Yuanmou County. Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis were broadly infecting multiple genera of animal hosts. In contrast, the small mammal genera Neodon, Dremomys, Ochotona, Anourosorex, and Mus were carrying individually specific rickettsial agents, indicating host tropism. There were 13 rickettsial species detected in 57.14% (8 out of 14) of tick species, with the highest prevalence (37.07%) observed in the genus Rhipicephalus. Eight rickettsial species were identified in 2375 livestock samples. Notably, six new Rickettsiales variants/strains were discovered, and Candidatus Rickettsia longicornii was unambiguously identified. CONCLUSIONS: This large-scale survey provided further insight into the high genetic diversity and overall prevalence of emerging Rickettsiales within endemic hotspots in Yunnan Province. The potential threats posed by these emerging tick-borne Rickettsiales to public health warrant attention, underscoring the need for effective strategies to guide the prevention and control of emerging zoonotic diseases in China.

Systematic investigation of the Borrelia miyamotoi spirochetes in ticks, wildlife and domestic animal hosts in Yunnan province, Southwest China.

Background: Borrelia miyamotoi is a spirochete species transmitted via hard ticks. Following its discovery in Japan, this pathogen has been detected around the world, and is increasingly confirmed as a human pathogen causing febrile disease, namely relapsing fever. Its presence has been confirmed in the Northeast China. However, there is little information regarding the presence of B. miyamotoi and other hard-tick-borne relapsing fever spirochetes in southern China including Yunnan province, where tick and animal species are abundant and many people both inhabit and visit for recreation. Methods: For the present study, we collected samples of ticks, wildlife, and domestic animal hosts from different counties in Yunnan province. Nucleic acids from samples were extracted, and the presence of B. miyamotoi and other relapsing fever spirochetes was confirmed using polymerase chain reaction (PCR) for the 16S rRNA specific target gene fragment. The positive samples were then amplified for partial genome of the flaB and glpQ genes. Statistical differences in its distribution were analyzed by SPSS 20 software. Sequence of partial 16S rRNA, flaB and glpQ genome were analyzed and phylogenetic trees were constructed. Results: A total of 8260 samples including 2304 ticks, 4120 small mammals and 1836 blood of domestic animal hosts were collected for screening for infection of B. miyamotoi and other relapsing fever spirochetes. Cattle and sheep act as the main hosts and Rhipicephalus microplus, Haemaphysalis nepalensis, H. kolonini and Ixodes ovatus were identified as the important vector host with high prevalence or wide distribution. Only one Mus caroli (mouse) and one Sorex alpinus (shrew) were confirmed positive for relapsing fever spirochetes. Evidence of vertical transmission in ticks was also confirmed. Two known strains of B. miyamotoi and one novel relapsing fever spirochetes, B. theileri-like agent, were confirmed and described with their host adaptation, mutation, and potential risk of spreading and spillover for human beings. Conclusions: Our results provide new evidence of relapsing fever spirochetes in vector and animal hosts in Yunnan province based on large sample sizes, and offer guidance on further investigation, surveillance and monitoring of this pathogen.

The basic properties of the electronic structure of the oxygen-evolving complex of photosystem II are not perturbed by Ca2+ removal.

Ca(2+) is an integral component of the Mn(4)O(5)Ca cluster of the oxygen-evolving complex in photosystem II (PS II). Its removal leads to the loss of the water oxidizing functionality. The S(2)' state of the Ca(2+)-depleted cluster from spinach is examined by X- and Q-band EPR and (55)Mn electron nuclear double resonance (ENDOR) spectroscopy. Spectral simulations demonstrate that upon Ca(2+) removal, its electronic structure remains essentially unaltered, i.e. that of a manganese tetramer. No redistribution of the manganese valence states and only minor perturbation of the exchange interactions between the manganese ions were found. Interestingly, the S(2)' state in spinach PS II is very similar to the native S(2) state of Thermosynechococcus elongatus in terms of spin state energies and insensitivity to methanol addition. These results assign the Ca(2+) a functional as opposed to a structural role in water splitting catalysis, such as (i) being essential for efficient proton-coupled electron transfer between Y(Z) and the manganese cluster and/or (ii) providing an initial binding site for substrate water. Additionally, a novel (55)Mn(2+) signal, detected by Q-band pulse EPR and ENDOR, was observed in Ca(2+)-depleted PS II. Mn(2+) titration, monitored by (55)Mn ENDOR, revealed a specific Mn(2+) binding site with a submicromolar K(D). Ca(2+) titration of Mn(2+)-loaded, Ca(2+)-depleted PS II demonstrated that the site is reversibly made accessible to Mn(2+) by Ca(2+) depletion and reconstitution. Mn(2+) is proposed to bind at one of the extrinsic subunits. This process is possibly relevant for the formation of the Mn(4)O(5)Ca cluster during photoassembly and/or D1 repair.

Distinct stepwise reduction of a nickel-nickel-bonded compound containing an α-diimine ligand: from perpendicular to coaxial structures.

A nickel-nickel-bonded complex, [{Ni(µ-L(.-))}2] (1; L=[(2,6-iPr2C6H3)NC(Me)]2), was synthesized from reduction of the LNiBr2 precursor by sodium metal. Further controllable reduction of 1 with 1.0, 2.0 and 3.0 equiv of Na, respectively, afforded the singly, doubly, and triply reduced compounds [Na(DME)3]·[{Ni(µ-L(.-))}2] (2; DME=1,2-dimethoxyethane), [Na(Et2O)]Na[(L(.-))Ni-NiL(2-)] (3), and [Na(Et2O)]2Na[L(2-)Ni-NiL(2-)] (4). Here L represents the neutral ligand, L(.-) denotes its radical monoanion, and L(2-) is the dianion. All of the four compounds feature a short Ni-Ni bond from 2.2957(6) to 2.4649(8) Å. Interestingly, they display two different structures: the perpendicular (1 and 2) and the coaxial (3 and 4) structure, in which the metal-metal bond axis is perpendicular to or collinear with the axes of the α-diimine ligands, respectively. The electronic structures, Ni-Ni bonding nature, and energetic comparisons of the two structure types were investigated by DFT computations.