Feasibility of initiating robotic surgery during the early stages of gastrointestinal surgery education.

PURPOSE: Minimally invasive surgery for gastrointestinal cancers is rapidly advancing; therefore, surgical education must be changed. This study aimed to examine the feasibility of early initiation of robotic surgery education for surgical residents. METHODS: The ability of staff physicians and residents to handle robotic surgical instruments was assessed using the da Vinci® skills simulator (DVSS). The short-term outcomes of 32 patients with colon cancer who underwent robot-assisted colectomy (RAC) by staff physicians and residents, supervised by a dual console system, between August 2022 and March 2024 were compared. RESULTS: The performances of four basic exercises were assessed after implementation of the DVSS. Residents required less time to complete these exercises and achieved a higher overall score than staff physicians. There were no significant differences in the short-term outcomes, operative time, blood loss, incidence of postoperative complications, and length of the postoperative hospital stay of the two surgeon groups. CONCLUSION: Based on the evaluation involving the DVSS and RAC results, it appears feasible to begin robotic surgery training at an early stage of surgical education using a dual console system.

CO2-Sensitive Porous Magnet: Antiferromagnet Creation from a Paramagnetic Charge-Transfer Layered Metal-Organic Framework.

Porous magnets that undergo a magnetic phase transition in response to gaseous adsorbates are desirable for the development of sustainable sensing and memory devices. Familiar gases such as O2 and CO2 are one class of target adsorbates because of their close association with life sciences and environmental issues; however, it is not easy to develop magnetic devices that respond to these ubiquitous gases. To date, only three examples of gas-responsive magnetic phase transitions have been demonstrated: (i) from a ferrimagnet to an antiferromagnet, (ii) its vice versa (i.e., change of magnetic phase), and (iii) from a ferrimagnet to a paramagnet (i.e., erasure of the magnetic phase). However, the creation of a magnet, meaning the change from a nonmagnet to a magnet by O2 or CO2 gas adsorption and magnetic switching by this phenomenon have not yet been explored. Herein, we report a CO2-induced antiferromagnet modified from a paramagnetic charge-flexible layered compound, [{Ru2(2,4-F2PhCO2)4}2TCNQ(OEt)2] (1; 2,4-F2PhCO2- = 2,4-difluorobenzoate; TCNQ(OEt)2 = 2,5-diethoxy-7,7,8,8-tetracyanoquinodimethane), where three molar equivalents of CO2 was accommodated at a CO2 pressure of 100 kPa. The magnetic change originates from charge fluctuation due to the transfer of electrons moving from the electron-donor to the electron-acceptor unit or vice versa, resulting in a change in the electron distribution induced by CO2 adsorption/desorption in the donor-acceptor-type charge transfer framework. Owing to the reversible electronic state change upon CO2 adsorption/desorption, these magnetic phases are switched, accompanied by modification of the electrical conductivity, which is boosted by the CO2 accommodation. This is the first example of the creation of a CO2-responsive magnet, which is promising for novel molecular multifunctional devices.

Densely Packed CO2 Aids Charge, Spin, and Lattice Ordering Partially Fluctuated in a Porous Metal-Organic Framework Magnet.

Partial charge fluctuations in the charge-ordered state of a material, often triggered by structural disorders and/or defects, can significantly alter its physical characteristics, such as magnetic long-range ordering. However, it is difficult to post-chemically fix such accidental partial fluctuations to reconstruct a uniform charge-ordered state. Herein, we report CO2 -aided charge ordering demonstrated in a CO2 -post-captured layered magnet, [{Ru2 (o-ClPhCO2 )4 }2 {TCNQ(OMe)2 }] ⋅ CO2 (1⊃CO2 ; o-ClPhCO2 - =ortho-chlorobenzoate; TNCQ(OMe)2 =2,5-dimethoxy-7,7,8,8-tetracyanoquinodimethane). Pristine porous layered magnet 1 had a partially charge-fluctuated ordered state, which provided ferrimagnetic ordering at TC =65 K. Upon loading CO2 , 1 adsorbed one mole of CO2 , forming 1⊃CO2 , and raising TC to 100 K. This was because of the vanishing charge fluctuations without significantly changing the framework structure. This research illustrates the post-accessible host-guest chemistry delicately combined with charge, spin, and lattice ordering in a spongy magnet. Furthermore, it highlights how this innovative approach opens up new possibilities for technology and nanoscale magnetism manipulation.

Considerations on Gated CO2 Adsorption Behavior in One-Dimensional Porous Coordination Polymers Based on Paddlewheel-Type Dimetal Complexes: What Determines Gate-Opening Temperatures?

Low-dimensional coordination polymers such as one-dimensional chains often exhibit gated guest sorption accompanying structural transition at a temperature (TG), which is associated with an external pressure of the guest (PG) characteristic to the material and guest used. This phenomenon can be evaluated using the Clausius-Clapeyron relationship with the equation d(ln PG)/d(1/TG) = ΔHG/R, where ΔHG and R are the transition enthalpy and gas constant, respectively. In this study, gated CO2 adsorption behavior was investigated in a one-dimensional chain based on a benzoate-bridged paddlewheel diruthenium(II,II) complex with a phenazine (phz) linker, [Ru2(p-MeOPhCO2)4(phz)] (1; p-MeOPhCO2- = p-anisate). Surprisingly, 1 underwent gate opening (GO)/closing (GC) at a much higher TG, e.g., 385 K for GC, under PCO2 = 100 kPa than those previously reported for such chain compounds, which usually appeared in the temperature range of 200-270 K. The transition entropy ΔSG in each system plays a key role in shifting TG; 1 results in a much smaller |ΔSG| in the series. Only 1 produced a CO2-accessible two-dimensional topological pore in its CO2-adsorbed phase 1⊃CO2, whereas the others reported previously produced one-dimensional or discrete topological pores for CO2 accommodation, strongly reflecting the degree of freedom of CO2 molecules in pores, which is related to ΔSG.

A Host-Guest Electron Transfer Mechanism for Magnetic and Electronic Modifications in a Redox-Active Metal-Organic Framework.

Host-guest electron transfer (HGET) in molecular framework systems is a critical trigger for drastic functional changes in both host framework and guest. A reversible magnetic phase transition was achieved via HGET in a layered framework, [{Ru2 (2,6-F2 PhCO2 )4 }2 (BTDA-TCNQ)] (1), where 2,6-F2 PhCO2 - and BTDA-TCNQ represent 2,6-difluorobenzoate and bis[1,2,5]dithiazolotetracyanoquinodimethane, respectively. The guest-free 1 with an antiferromagnetic ground state transformed into a paramagnet, [{Ru2 (2,6-F2 PhCO2 )4 }2 (BTDA-TCNQ)]I3 (1-I3 ), by adsorbing iodine (I2 ). The local charge distribution of [{Ru2 II,III }+ -(BTDA-TCNQ).- -{Ru2 II,II }] in 1 was reversibly modified to [{Ru2 II,III }+ -(BTDA-TCNQ)0 -{Ru2 II,II }](I3 - ) in 1-I3 through HGET. Theoretical calculations of 1-I3 indicated a partial charge delocalization as [{Ru2 }(1-δ)+ -(BTDA-TCNQ)0 -{Ru2 }δ+ ](I3 - ) with δ≈0.2, aided by weak ferromagnetic coupling. 1-I3 exhibited a hundred-fold enhancement in electrical conductivity compared to that of 1.

Magnet Creation by Guest Insertion into a Paramagnetic Charge-Flexible Layered Metal-Organic Framework.

Changing nonmagnetic materials to spontaneous magnets is an alchemy-inspiring concept in materials science; however, it is not impossible. Here, we demonstrate chemical modification from a nonmagnet to a bulk magnet of either a ferrimagnet or antiferromagnet, depending on the adsorbed guest molecule, in an electronic-state-flexible layered metal-organic framework, [{Ru2(2,4-F2PhCO2)4}2TCNQ(EtO)2] (1; 2,4-F2PhCO2- = 2,4-difluorobenzoate; TCNQ(EtO)2 = 2,5-diethoxy-7,7,8,8-tetracyanoquinodimethane). The guest-free paramagnet 1 undergoes a thermally driven intralattice electron transfer involving a structural transition at 380 K. This charge modification can also be implemented by guest accommodations at room temperature; 1 adsorbs several organic molecules, such as benzene (PhH), p-xylene (PX), 1,2-dichloroethane (DCE), dichloromethane (DCM), and carbon disulfide (CS2), forming 1-solv with intact crystallinity. This induces an intralattice electron transfer to produce a ferrimagnetically ordered magnetic layer. According to the interlayer environment tuned by the corresponding guest molecule, the magnetic phase is consequently altered to a ferrimagnet for the guests PhH, PX, DCE, and DCM or an antiferromagnet for CS2. This is the first demonstration of the postsynthesis of bulk magnets using guest-molecule accommodations.

Tunable Synchronicity of Molecular Valence Tautomerism with Macroscopic Solid-Liquid Transition by Molecular Lattice Engineering.

The combination of a cobalt-dioxolene core that exhibits valence tautomerism (VT) with pyridine-3,5-dicarboxylic acid functionalized with chains bearing two, four, or six oxyethylene units led to new complexes ConEGEspy (n = 2, 4, and 6). These complexes commonly form violet crystals of the low-spin (ls)-[CoIII (nEGEspy)2 (3,6-DTBSQ)(3,6-DTBCat)] (ls-[CoIII ], 3,6-DTBSQ = 3,6-di-tert-butyl semiquinonato, 3,6-DTBCat = 3,6-di-tert-butyl catecholato). Interestingly, violet crystals of Co2EGEspy in the ls-[CoIII ] transitioned into a green liquid, accompanied by an almost complete VT shift (94 %) to the high-spin (hs)-[CoII (nEGEspy)2 (3,6-DTBSQ)2 ] (hs-[CoII ]) upon melting. In contrast, violet crystals of Co4EGEspy and Co6EGEspy in the ls-[CoIII ] exhibited partial VT (33 %) and only a 9.3 % VT shift after melting, respectively. These data demonstrate the tunability of the synchronicity of the molecular VT and macroscopic solid-liquid transitions by optimizing the tethered chains, thus establishing a new strategy for coupling bistable molecules with the macroscopic world.

Molecular motion in the nanospace of MOFs upon gas adsorption investigated by in situ Raman spectroscopy.

Molecular motions taking place in the nanospace of metal-organic frameworks (MOFs) are an interesting research subject, although not yet fully investigated. In this work, we utilized in situ Raman spectroscopy in the ultralow-frequency region to investigate the libration motion (including the rotational motion of phenylene rings) of MOFs, in particular [Cu2(bdc)2(dabco)] (Cu-JAST-1), where bdc = 1,4-benzenedicarboxylate and dabco = 1,4-diazabicyclo[2.2.2]octane. The libration mode of Cu-JAST-1 was found to be significantly suppressed by the adsorption of various guest molecules, such as CO2, Ar, and N2. In addition, an appreciable correlation between the libration mode and adsorption equilibrium time was identified, which provides useful novel tools in the design of MOFs acting as molecular adsorption and separation materials.

Ionicity Diagrams for Electron-Donor and -Acceptor Metal-Organic Frameworks: DA Chains and D2A Layers Obtained from Paddlewheel-Type Diruthenium(II,II) Complexes and Polycyano-Organic Acceptors.

Recent developments in research concerning metal-organic frameworks and coordination polymers have provided the successful design of charge-variable molecular frameworks. However, few comprehensive studies exist that investigate the control of charge states in series of molecular frameworks such as these. Herein, we discuss the ionicity diagrams of two series containing electron-donor (D) and -acceptor (A) units: one-dimensional DA chains and two-dimensional D2A layers. The series were obtained by reacting paddlewheel-type diruthenium(II,II) complexes ([Ru2II,II]), which served as D units, with the polycyano-organic acceptors N,N'-dicyanoquinodiimine (DCNQI) and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ), which served as A units. Fifteen novel members of neutral charged DA chains were fabricated in this study to characterize the ionicity diagrams for DA and D2A systems.

Magnetic Correlation Engineering in Spin-Sandwiched Layered Magnetic Frameworks.

The insertion of "sandwiched spins" between magnetic layers could efficiently affect the interlayer magnetic correlations, but doing so increases the complexity in the interlayer spin alignment because of competition between the inserted spin-layer interaction JNNI and the interlayer through-space interaction JNNNI if the magnitude of JNNI is of the same order as JNNNI with reciprocal signs of the respective interactions. Herein, systematic tuning of the magnetic phase variations by JNNI and JNNNI in two kinds of metal-variable isostructural series of supramolecular pillared layer magnets [MCp*2 ][{Ru2 II,II (2,3,5,6-F4 CO2 )4 }2 (TCNQ)]⋅2 DCE (M=Co, Fe, Cr; 2,3,5,6-F4 PhCO2 - =2,3,5,6-tetrafluorobenzoate; TCNQ=7,7,8,8-tetracyano-p-quinodimethane; DCE=1,2-dichloroethane) and their DCE-free series, in which [MCp*2 ]+ (Cp*=η5 -C5 Me5 ) species with S=0, 1/2, and 3/2 for M=Co, Fe, Cr, respectively, are sandwiched between ferrimagnetic layers of [{Ru2 }2 (TCNQ)]- , is demonstrated. The results showed that the flexible magnetic natures of these magnets are changeable in dependence on JNNI and JNNNI , as well as on interlayer inserted spins M.

CO2 -Induced Spin-State Switching at Room Temperature in a Monomeric Cobalt(II) Complex with the Porous Nature.

CO2 -responsive spin-state conversion between high-spin (HS) and low-spin (LS) states at room temperature was achieved in a monomeric cobalt(II) complex. A neutral cobalt(II) complex, [CoII (COO-terpy)2 ]⋅4 H2 O (1⋅4 H2 O), stably formed cavities generated via π-π stacking motifs and hydrogen bond networks, resulting in the accommodation of four water molecules. Crystalline 1⋅4 H2 O transformed to solvent-free 1 without loss of porosity by heating to 420 K. Compound 1 exhibited a selective CO2 adsorption via a gate-open type of the structural modification. Furthermore, the HS/LS transition temperature (T1/2 ) was able to be tuned by the CO2 pressure over a wide temperature range. Unlike 1 exhibits the HS state at 290 K, the CO2 -accomodated form 1⊃CO2 (P CO 2 =110 kPa) was stabilized in the LS state at 290 K, probably caused by a chemical pressure effect by CO2 accommodation, which provides reversible spin-state conversion by introducing/evacuating CO2 gas into/from 1.

In Situ Tracking of Dynamic NO Capture through a Crystal-to-Crystal Transformation from a Gate-Open-Type Chain Porous Coordination Polymer to a NO-Adducted Discrete Isomer.

Optimal control of gas adsorption properties in metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) remains a great challenge in the field of materials science. An efficient strategy to capture electron-acceptor-type gas molecules such as nitrogen monooxide (NO) is to use host-guest interactions by utilizing electron-donor-type MOFs/PCPs as host frameworks. Herein, we focus on a highly electron-donating chain compound by using the paddlewheel-type [Ru2 II,II ] complex [Ru2 (2,4,5-Me3 PhCO2 )4 ] (2,4,5-Me3 PhCO2 - =2,4,5-trimethylbenzoate) with the phenazine (phz) linker: [Ru2 (2,4,5-Me3 PhCO2 )4 (phz)] (1). Compound 1 exhibited a specific gated adsorption for NO under gas pressures greater than 60 kPa at 121 K, which finally resulted in approximately seven molar equivalents being taken up at 100 kPa followed by four molar equivalents remaining under vacuum at 121 K; its Rh isomorph (2) with weaker donation ability was inactive for NO. When the sample of 1⊃4 NO was heated to room temperature, the compound underwent a crystal-to-crystal phase transition to give [Ru2 (2,4,5-Me3 PhCO2 )4 (NO)2 ](phz) (1-NO), involving a post-synthetic nitrosylation on the [Ru2 ] unit, accompanied by an eventful site-exchange with phz. This drastic event, which is dependent on the NO pressure, temperature, and time, was coherently monitored by using several different in situ techniques, revealing that the stabilization of NO molecules in nanosized pores dynamically and stepwisely occurred with the support of strong electronic/magnetic host-guest interactions.

Host-Guest Hydrogen Bonding Varies the Charge-State Behavior of Magnetic Sponges.

The electron-donor(D) and -acceptor(A)-assembled D2 A-layer framework [{Ru2 (m-FPhCO2 )4 }2 TCNQ(OMe)2 ]⋅nDCE (1-nDCE; m-FPhCO2 - =m-fluorobenzoate; TCNQ(OMe)2 =2,5-dimethoxyl-7,7,8,8-tetracyanoquinodimethane; DCE=1,2-dichloroethane) undergoes drastic charge-ordered state variations via three distinct states that are a two-electron-transferred state (2e-I), a charge-disproportionated state (1.5e-I), and a one-electron-transferred state (1e-I), depending on the degree of solvation by nDCE. The pristine form 1-4DCE has a paramagnetic 2e-I state, which eventually produces the solvent-free form 1 in 1.5e-I via an intermediate state 1-nDCE (n≤1) in 1e-I. Resolvation of 1 stabilizes 1-DCE, allowing it to switch between 1.5e-I and 1e-I, and to become ferrimagnetic with a Tc of 30 K (1.5e-I) and 88 K (1e-I). The stabilization of the 1e-I state of 1-DCE is due to the presence of host-guest hydrogen bonding that enables to suppress the electron-donation ability of D even in an identical framework with 1.

Magnetic Sponge Behavior via Electronic State Modulations.

A reversible magnetic change in response to external stimuli is a desired function of molecular magnetic materials. The magnetic change induced by a change in the intrinsic spin is significant because the magnetic change is inevitable and could become drastic. In this study, we demonstrate a reversible magnetic change closely associated with electronic state modulations, as well as structural modifications realized by solvation/desolvation cycles of a magnetic sponge. The compound was a D2A-type layered magnet, [{Ru2(O2CPh-2,3,5-Cl3)4}2(TCNQMe2)]·4DCM (1; 2,3,5-Cl3PhCO2- = 2,3,5-trichlorobenzoate; TCNQMe2 = 2,5-dimethyl-7,7,8,8-tetracyanoquinodimethane; DCM = dichloromethane), where [Ru2(O2CPh-2,3,5-Cl3)4] ([Ru2II,II]) is an electron donor (D) and TCNQMe2 is an electron acceptor (A). Compound 1 had a one-electron-transferred, charge-ordered state with a [{Ru2II,II}-TCNQMe2•--{Ru2II,III}+] (1e-I) formula. Strong intralayer antiferromagnetic couplings between [Ru2II,II] with S = 1 or [Ru2II,III]+ with S = 3/2 and TCNQMe2•- with S = 1/2, as well as ferromagnetic interlayer interactions, induced long-range ferrimagnetic ordering at Tc = 101 K. Interstitial DCM molecules were located between layers, and these were gradually eliminated under vacuum at 80 °C to form a solvent-free compound (1-dry) without loss of crystallinity. The electronic state of 1-dry thermally fluctuated and eventually provided a charge-disproportionate disordered state, with a [{Ru2}0.5+-TCNQMe21.5--{Ru2II,III}+] (1.5e-I) formula as the ground state. The Tc in 1-dry was 34 K because of the presence of diamagnetic TCNQMe22- in some parts of the framework. A large Tc variation with Δ Tc ≈ 70 K was switchable; switching was achieved by charge-state modulations accompanied by subtle structural modifications in solvation/desolvation treatments.

Magnetic Switching by the In Situ Electrochemical Control of Quasi-Spin-Peierls Singlet States in a Three-Dimensional Spin Lattice Incorporating TTF-TCNQ Salts.

Magnetic phase switching in a coordination polymer is reported, which is demonstrated by combining two processes: (A) the pre-organization of magnetic/redox-active molecules into a framework, and (B) a post-treatment through electrochemical tuning of the pre-organized molecules. A TTF.+ -TCNQ.- salt (TTF=tetrathiafulvalene; TCNQ=7,7,8,8-tetracyano-p-quinodimethane) was incorporated into a three-dimensional framework with paddlewheel-type dimetal(II, II) units ([M2II,II ]; M=Ru with S=1, 1; and Rh with S=0, 2), where the [M2II,II ] and TCNQ.- units form the coordinating framework, and TTF.+ is located in the pores of framework, forming an irregular π-stacking alternating column with the TCNQ.- in the framework. In 1, the spins of [Ru2II,II ] and TCNQ.- units make a magnetic correlation through the framework upon decreasing the temperature from 300 K, which is, however, suddenly suppressed below 137 K (=Td (1)) by the formation of a spin singlet in the TTF.+ -TCNQ.- columns, as seen in the spin-Peierls transition (Td (2)=200 K). This material was incorporated as a cathode in a Li-ion battery (LIB); a long-range ferrimagnetic correlation was formed through the three-dimensional [{Ru2II,II }2 TCNQ]- framework at Tc =78 K in the discharge process. The reversible magnetic phase switching between the non-volatile ferrimagnetic and paramagnetic states, resulting from the local spin tuning of quasi-spin-Peierls singlet, is demonstrated through the discharge/charge cycling of the LIB.

One-Dimensional Chains of Paddlewheel-Type Dichromium(II,II) Tetraacetate Complexes: Study of Electronic Structure Influenced by σ- and π-Donation of Axial Linkers.

Paddlewheel-type carboxylate-bridged dichromium(II,II) complexes possess intriguing properties such as high redox activity and thermally assisted paramagnetism. However, the relationship of their structures with electronic states and physical properties has not been extensively studied. In this work, we investigated a series of one-dimensional chain complexes based on the paddlewheel-type dichromium(II,II) tetraacetate complex ([Cr2II,II(OAc)4] = [Cr2II,II]) with pyridine/pyrazine-type organic linkers (µ2-Lax) having different σ- and π-donating abilities to clarify the electronic structure of [Cr2II,II] assemblies. The chain compounds are stable in air, probably owing to their robust polymerized forms. X-ray crystallographic studies and magnetic measurements revealed that the basicity (p Kb) of Lax, which quantitatively correlates with the σ-donor strength of Lax, modulates the Cr-Cr and Cr-Lax distances and the energy separation ( ES-T) between the diamagnetic (singlet) and thermally populated paramagnetic (triplet) states. The Cr-Cr and Cr-Lax distances are strongly influenced by σ- and π-donation from Lax, while the frontier δ orbital makes only a small contribution to the structural features. Density functional theory calculations were conducted to clarify this issue. The calculations produced the following unanticipated results against the long-known model: (i) the σ bonding orbital is the HOMO and dominates bonding in the [Cr2II,II] unit, (ii) the total Cr-Cr bond order is less than 1.0, and (iii) the δ orbital electron density is almost completely localized on the chromium sites. The computational results accurately predict the magnetic behavior and provide evidence for a new configuration of frontier orbitals in [Cr2II,II(RCO2)4(Lax)2].

Regulation of NO Uptake in Flexible Ru Dimer Chain Compounds with Highly Electron Donating Dopants.

On-demand design of porous frameworks for selective capture of specific gas molecules, including toxic gas molecules such as nitric oxide (NO), is a very important theme in the research field of molecular porous materials. Herein, we report the achievement of highly selective NO adsorption through chemical doping in a framework (i.e., solid solution approach): the highly electron donating unit [Ru2(o-OMePhCO2)4] (o-OMePhCO2- = o-anisate) was transplanted into the structurally flexible chain framework [Ru2(4-Cl-2-OMePhCO2)4(phz)] (0; 4-Cl-2-OMePhCO2- = 4-chloro-o-anisate and phz = phenazine) to obtain a series of doped compounds, [{Ru2(4-Cl-2-OMePhCO2)4}1-x{Ru2(o-OMePhCO2)4}x(phz)] (x = 0.34, 0.44, 0.52, 0.70, 0.81, 0.87), with [Ru2(o-OMePhCO2)4(phz)] (1) as x = 1. The original compound 1 was made purely from a "highly electron donating unit" but had no adsorption capability for gases because of its nonporosity. Meanwhile, the partial transplant of the electronically advantageous [Ru2(o-OMePhCO2)4] unit with x = 0.34-0.52 in 0 successfully enhanced the selective adsorption capability of NO in an identical structurally flexible framework; an uptake at 95 kPa that was 1.7-3 mol/[Ru2] unit higher than that of the original 0 compound was achieved (121 K). The solid solution approach is an efficient means of designing purposeful porous frameworks.

Construction of an Artificial Ferrimagnetic Lattice by Lithium Ion Insertion into a Neutral Donor/Acceptor Metal-Organic Framework.

Construction of a molecular system in which the magnetic lattice exhibits long-range order is one of the fundamental goals in materials science. In this study, we demonstrate the artificial construction of a ferrimagnetic lattice by doping electrons into acceptor sites of a neutral donor/acceptor metal-organic framework (D/A-MOF). This doping was achieved by the insertion of Li-ions into the D/A-MOF, which was used as the cathode of a Li-ion battery cell. The neutral D/A-MOF is a layered system composed of a carboxylate-bridged paddlewheel-type diruthenium(II,II) complex as the donor and a TCNQ derivative as the acceptor. The ground state of the neutral form was a magnetically disordered paramagnetic state. Upon discharge of the cell, spontaneous magnetization was induced; the transition temperature was variable. The stability of the magnetically ordered lattice depended on the equilibrium electric potential of the D/A-MOF cathode, which reflected the electron-filling level.

Electron-Transferred Donor/Acceptor Ferrimagnet with T(C) = 91 K in a Layered Assembly of Paddlewheel [Ru2] Units and TCNQ.

The donor (D)/acceptor (A) assembly reaction of the paddlewheel-type diruthenium(II,II) complex [Ru2(2,4,6-F3PhCO2)4(THF)2] (2,4,6-F3PhCO2(-) = 2,4,6-trifluorobenzoate; abbreviated hereafter as [Ru2]) with 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) in a p-xylene/CH2Cl2 solvent system led to the formation of a two-dimensional layered compound, [{Ru2(2,4,6-F3PhCO2)4}2(TCNQ)]·2(p-xylene)·2CH2Cl2 (1). As expected from this D/A combination, 1 has a one-electron-transfer ionic state with the D(0.5+)2A(-) formulation. This state formally derives a heterospin state composed of S = 1 for [Ru(II,II)2], S = 3/2 for [Ru(II,III)2](+), and S = ½ for TCNQ(•-), possibly causing intralayer ferrimagnetic spin ordering. Most of these types of compounds have an antiferromagnetic ground state because of the coupling of ferrimagnetically ordered layers in dipole antiferromagnetic interactions. However, 1 became a three-dimensional ferrimagnet with T(C) = 91 K because of the presence of interlayer ferromagnetic interactions.

Fully electron-transferred donor/acceptor layered frameworks with TCNQ(2-).

In a series of two-dimensional layered frameworks constructed by two electron-donor (D) and one electron-acceptor (A) units (a D2A framework), two-electron transferred systems with D(+)2A(2-) were first synthesized as [{Ru2(R-PhCO2)4}2(TCNQRx)]·n(solv) (R = o-CF3, Rx = H2 (1), R = o-CF3, Rx = Me2 (2), R = o-CF3, Rx = F4 (3), R = o-Me, TCNQRx = BTDA-TCNQ (4), R = p-Me, TCNQRx = BTDA-TCNQ (5), where TCNQ is 7,7,8,8-tetracyano-p-quinodimethane and BTDA-TCNQ is bis[1,2,5]dithiazolotetracyanoquinodimethane). The D(+)2A(2-) system was synthesized by assembling D/A combinations of paddlewheel-type [Ru2(II,II)(R-PhCO2)4] complexes and TCNQRx that possibly caused a large gap between the HOMO of D and the LUMO of A (ΔEH-L(DA)). All compounds were paramagnetic because of quasi-isolated [Ru2(II,III)](+) units with weakly antiferromagnetically coupled S = 3/2 spins via diamagnetic TCNQRx(2-) and/or through the interlayer space. The ionic states of these compounds were determined using the HOMO/LUMO energies and redox potentials of the D and A components in the ionization diagram for ΔEH-L(DA) vs ΔE1/2(DA) (= E1/2(D) - E1/2(A); E1/2 = first redox potential) as well as by previously reported data for the D2A and DA series of [Ru2]/TCNQ, DCNQI materials. The boundary between the one-electron and the two-electron transferred ionic regimes (1e-I and 2e-I, respectively) was not characterized. Therefore, another diagram for ΔEH-L(DA) vs |(2)E1/2(A) - (1)E1/2(A)|, where (2)E1/2(A) and (1)E1/2(A) are the second and first redox potentials of TCNQRx, respectively, was used because the 2e-I regime is dependent on on-site Coulomb repulsion (U = |(2)E1/2(A) - (1)E1/2(A)|) of TCNQRx. This explained the oxidation states of 1-5 and the relationship between ΔEH-L(DA) and U and allowed us to determine whether the ionic regime was 1e-I or 2e-I. These diagrams confirm that a charge-oriented choice of building units is possible even when designing covalently bonded D2A framework systems.