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This work reports that the redox-active metalloligand (ML) fac-[CrIII(mp)3]3− (mp: 2-mercaptophenolato) coordinates with a Co(III) ion to afford the trianionic complex [CoIII{fac-CrIII(mp)3}2]3−. The free ML shows ligand-centered redox processes, whereas the guest-metal-bound trinuclear structure exhibited a guest-metal-centered Co(II)/Co(III) redox couple, demonstrating redox switching through guest-metal binding to the MLs. [ABSTRACT FROM AUTHOR]

Valence tautomerism (VT) refers to equilibria between two or more different tautomers differing in their charge distributions. This contribution shows how molecular VT occurring in metal-dioxolene complexes (metal = cobalt, manganese) functionalized with long alkyl chains can be coupled with several types of macroscopic phase transformations, such as solid-to-solid and solid-to-liquid transitions and the double-melting phenomenon. Observations of simultaneous transformation of molecular and macroscopic states have led to the concept of synchronic bistability. The central focus in this microreview is on molecular design, thermodynamic basis, and kinetic control of the synchronic bistability. It is demonstrated that a key factor in designing a synchronic transformation is to build up strong interdependent correlations between molecules and their assembled states. [ABSTRACT FROM AUTHOR]

Abstract: Dynamic properties of a diruthenium complex with ligand-unsupported Ru–Ru triple bonds, Na2[Ru2(3,6-DTBCat)4] (1), were studied using variable-temperature 1H NMR. Structural freedom derived from the ligand-unsupported structure leads to torsional motion about the Ru–Ru bonds in THF and in DMF. The observed solvent dependency corresponds to the electrostatic interactions between the diruthenium complex and Na+ counter cations, which are sensitive to the polarity of solvents. In addition, a new diruthenium complex, [{Na(THF)2(H2O)}{Na(THF)0.5(H2O)}{Ru2(3,6-DTBCat)2(H4Cat)2}] (2·2.5THF·2H2O), with a ligand-unsupported Ru–Ru bond surrounded by two different kinds of catecholate derivatives, has been synthesized and crystallographically characterized. The complex, which was characterized by single-crystal structural analysis, will provide an opportunity to investigate not only static molecular structures but also dynamic physicochemical properties in comparison with analogues containing four identical catecholate derivatives. [Copyright &y& Elsevier]

The molecular structures and physicochemical properties of diruthenium complexes with ligand-unsupported Ru-Ru bonds, generally formulated as [A2{Ru2(DTBCat)4}] (DTB = 3,5- or 3,6-di-tert-butyl; Cat2- = catecholate), were studied in detail by changing the countercations. First, the binding structures of the cations in a family of [{ A(DME)n}2{ Ru2(3,5-DTBCat)4}] (n = 2 for A+ = Li+ and Na+ and n = 1 for A+ = K+ and Rb+) were systematically examined to reveal the effects of the cations on the molecular structures and electrochemical properties. Second, the complex (n-Bu4N)2[Ru2(3,6-DTBCat)4] with a cation-free structure was synthesized using tetra-n-butylammonium cations. The complex clearly demonstrates first that the ligand-unsupported Ru-Ru bonds are essentially stabilized by the dianionic nature of the catecholate derivatives without any other bridging or supporting species. In contrast, the redox potentials and absorption spectra of the complexes can sensitively respond to the countercations depending upon the polarity of the solvents. [ABSTRACT FROM AUTHOR]

A family of diruthenium complexes with ligand-unsupported Ru-Ru bonds has been systematically synthesized, and their crystal structures and physical properties have been examined. A simple, useful reaction between Ru2(OAc)4Cl (OAc- = acetate) and catechol derivatives in the presence of bases afforded a variety of diruthenium complexes, generally formulated as [Nan{Ru2(R4Cat)4}] (n = 2 or 3; R4 = -F4, -Cl4, -Br4, -H4, -3,5-di-t-Bu, and -3,6-di-t-Bu; Cat2- = catecholate). The most characteristic feature of the complexes is the formation of short ligand-unsupported Ru-Ru bonds (2.140–2.273 Å). These comprehensive studies were carried out to evaluate the effects of the oxidation states and the substituents governing the molecular structures and physicochemical properties. The Ru-Ru bond distances, rotational conformations, and bending structures of the complexes were successfully varied. The results presented in this manuscript clearly demonstrate that the complexes with ligand-unsupported Ru-Ru bonds can sensitively respond to redox reactions and ligand substituents on the basis of the greater degree of freedom in their molecular structures. [ABSTRACT FROM AUTHOR]

Three novel one-dimensional coordination polymers with pyridazine (pdz),[M (pdz) Cl 2 ] n (M = Cu (II) ( 1 ), Fe (II) ( 2 ), Mn (II) ( 3 )), were synthesized and characterized. All the compounds have one-dimensional zigzag chain structures. The copper ion in compound 1 has a planer coordination sphere with two bridging pdz ligands and two C1 - anions, while the metal ions in the other compounds have a distorted octahedral environment with pdz and Cl - groups both acting as bridges. The magnetic data of these compounds show antiferromagnetic interaction between the magnetic centers within the chains. [ABSTRACT FROM AUTHOR]

Tris(tetrahalogeno- o -semiquinonate) chromium (III) complexes, Cr III (Cl 4 SQ) 3 ·4C 6 H 6 ( 1 ) and Cr III (Br 4 SQ) 3 ·4C 6 H 6 ( 2 ), crystallize in an isostructural form; tetragonal, P 4 1 2 1 2 with a = 13.452(2) Å 3 , c = 24.78(2) Å, V = 4484(3) Å 3 and a = 13.7465(7) Å, c = 25.680(1)Å, V = 4852.6(4) Å 3 for 1 and 2 , respectively. The inner coordination environments of the complex molecules are similar to that of previously reported crystal, Cr III (Cl 4 SQ) 3 ·CS 2 ·1/2C 6 H 6 , while both complexes show strong π&middot··;π interaction between the three SQ ligands and the four solvate benzene molecules, resulting the formation of two-dimensional π···π stacking array. The effect of π·π interactions was evaluated by thermogravimetric and differential scanning calorimetric analysis where the weigh loss corresponding to the four benzene molecules was observed up to 500 K indicative of the interactions between the ligands and solvated benzene molecules. [ABSTRACT FROM AUTHOR]

Photocatalytic molecular conversions that lead to value-added chemicals are of considerable interest. To achieve highly efficient photocatalytic reactions, it is equally important as it is challenging to construct systems that enable effective charge separation. Here, we demonstrate that the rational construction of a biphasic solution system with a ferrocenium/ferrocene (Fc+/Fc) redox couple enables efficient photocatalysis by spatial charge separation using the liquid–liquid interface. In a single-phase system, exposure of a 1,2-dichloroethane (DCE) solution containing a Ru(II)- or Ir(III)-based photosensitizer, Fc, and benzyl bromide (Bn-Br) to visible-light irradiation failed to generate any product. However, the photolysis in a H2O/DCE biphasic solution, where the compounds are initially distributed in the DCE phase, facilitated the reductive coupling of Bn-Br to dibenzyl (Bn2) using Fc as an electron donor. The key result of this study is that Fc+, generated by photooxidation of Fc in the DCE phase, migrates to the aqueous phase due to the drastic change in its partition coefficient compared to that of Fc. This liquid–liquid phase migration of the mediator is essential for facilitating the reduction of Bn-Br in the DCE phase as it suppresses backward charge recombination. The co-existence of anions can further modify the driving force of phase migration of Fc+ depending on their hydrophilicity; the best photocatalytic activity was obtained with a turnover frequency of 79.5 h−1 and a quantum efficiency of 0.2% for the formation of Bn2 by adding NBu4+Br− to the biphasic solution. This study showcases a potential approach for rectifying electron transfer with suppressed charge recombination to achieve efficient photocatalysis. [ABSTRACT FROM AUTHOR]

The oxidation of [MII(3,5‐DTBCat)(DTBbpy)] (M=Ni ([Ni]), Pd ([Pd]), and Pt ([Pt]); 3,5‐DTBCat=3,5‐di‐tert‐butylcatecholato; DTBbpy=4,4′‐di‐tert‐butyl‐2,2′‐bipyridine) afforded the dimeric {[NiII(3,5‐DTBSQ)(DTBbpy)](PF6)}2 ({[Ni](PF6)}2; 3,5‐DTBSQ=3,5‐di‐tert‐butylsemiquinonato) and monomeric semiquinonato (SQ) complexes [MII(3,5‐DTBSQ)(DTBbpy)](PF6) (M=Pd ([Pd](PF6)) and Pt ([Pt](PF6))). The negative solvatochromic properties of the SQ complexes allowed us to estimate the relative order of their dipole moments: [Pd](PF6)>[Pt](PF6)>{[Ni](PF6)}2. The complexes [Pd](PF6) and [Pt](PF6) adopt monomeric structures and are stable in CH2Cl2 and toluene, whereas they gradually disproportionate at room temperature to [M] and 3,5‐di‐tert‐butylbenzoquinone (3,5‐DTBBQ) in polar solvents such as THF, MeOH, EtOH, DMF, or DMSO. The results of spectroscopic studies suggested that the oxidized nickel complex adopts a monomeric structure ([Ni](PF6)) in CH2Cl2, but a dimeric structure ({[Ni](PF6)}2) in the other investigated solvents. In polar solvents, {[Ni](PF6)}2 may disproportionate to [Ni] and 3,5‐DTBBQ at 323 K, thereby demonstrating a significant solvent‐ and metal‐dependence in temperature. The relative activities of {[Ni](PF6)}2 and [M](PF6) toward disproportionation are related to the electrochemically estimated Kdis values in CH2Cl2 and DMF. The present work demonstrates that solvent polarity and the dipole moments of the SQ complexes promote disproportionation, which can be controlled by a judicious choice of the metal ion, solvent, and temperature. [ABSTRACT FROM AUTHOR]

Methylation of the molybdenum sulfide cluster unit [Mo6S8(PEt3)6] (1) with CH3OTf resulted in the formation of mono‐ and dimethylated cluster units, [Mo6S8–x(SCH3)x(PEt3)6]OTf·yCH2Cl2 {[2]OTf·0.5CH2Cl2 (x = 1, y = 0.5) and [3]OTf·CH2Cl2 (x = 2, y = 1)}. Structural and electrochemical investigations revealed that the methylation of the µ3‐S ligand(s) induced a characteristic structural distortion of the [Mo6S8] cluster core and enhanced its ability to accept multiple electrons. [ABSTRACT FROM AUTHOR]

[Display omitted] • New synthetic and catalytic design with redox-active ligands/non-innocent ligands (RALs/NILs). • RALs/NILs is use for supplying and pooling multiple electrons and active hydrogen species. • RALs/NILs can act as spectators, moderators, suppliers/poolers, cooperators, or actors. • Excited-state hydrogen detachment (ESHD) as an alternative trigger for chemical reactions. • The ESHDs of a RAL/NIL realize various photochemical reactions in solution. • Chemical-, electrochemical- and photochemical activations of a RAL/NIL are described. A central issue in the design of reactions and catalysts based on metal complexes is the hybridization of functional ligands with metal atoms. Recent studies have demonstrated that redox-active/non-innocent ligands can potentially act as spectators, moderators, electron/H+/0/– supplier/poolers, cooperators, or actors, depending on their role(s) in the reaction. In this review, we will highlight selected stoichiometric or catalytic reactions driven by substituted ethylenes and dithiolenes, as well as six-membered ligands, such as catecholato, benezendithiolato, aminophenolato, and o -phenelyenediamine derivatives. Chemically, electrochemically, and photochemically induced lability of these ligands can be expected to provide an enriched recipe for a platform toward useful bond-activation and bond-formation processes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We synthesized a novel Pt(II)--diimine complex with a typical ambidentate thiocyanato ligand, [Pt(thiocyanato)2(H2dcbpy)] (1j H2dcbpy =4,4'-dicarboxy-2)2'-bipyridine), and found that the complex 1 exhibits unique linkage isomerizations with drastic color and luminescence changes driven by exposure to volatile organic chemical (VOC) vapors in the solid state. Reaction between [PtCl2(H2dcbpy)] and KSCN in aqueous solution at 0 °C enabled successful isolation of an isomer with the S-coordinated thiocyanato ligand, [Pt(SCN)2(H2dcbpy)] (1SS·H2O), as a nonluminescent orange solid, Interestingly, 1SS·H2O was isomerized completely to one isomer with the N-coordinated isothiocyanato ligand, [Pt(NCS)2(H2dcbpy)] (1NN·3DMF) by exposure to DMF vapor, and this isomerization was accompanied by significant color and luminescence changes from nonluminescent orange to luminescent red. IR spectroscopy and thermogravimetric analysis revealed that adsorption of the DMF vapor and transformation of the hydrogen-bonded structure both played important roles in this vapor-induced linkage isomerization. Another isomer containing both S- and N-coordinated thiocyanato ligands, [Pt(SCN)(NCS)(H2dcbpy)] (1SN), was obtained as a nonluminescent yellow solid simply by exposure of 1SS·H2O to acetone vapor at room temperature, and about 80% of 1SS&niddot;H2O was found to be converted to ISN. In the solution state, each isomer changed gradually to an isomeric mixture, but pure 1SS was regenerated by UV light irradiation (λirr = 300 nm) of an MeOH solution of the mixture. In the crystal structure of 1SN, the complex molecules were hydrogen-bonded to each other through the carboxyl groups of the H2dcbpy ligand and the N site of the thiocyanato ligand, whereas the 1NN molecules in the 1NN·4DMF crystal were hydrogen-bonded to the solvated DMF molecules. Competition of the hydrogen-bonding abihty among the carboxyl groups of the H2dcbpy ligand, N and S atoms of the thiocyanato ligand, and the vapor molecule was found to be one of the most important factors controlling linkage isomerization behavior in the solid state. This unique linkage isomerization controlled by vapor can provide an outstanding vapochromic system as well as a new molecular sTvitching function driven by vapor molecules. [ABSTRACT FROM AUTHOR]

We previously reported that a tris-(o-phenylenediamine) iron(II) complex promotes photochemical H2 generation and C–H carboxylation of o-phenylenediamine without any additives under N2 and CO2 atmospheres, respectively, in tetrahydrofuran at room temperature. Herein, the key mechanistic process, namely, excited-state hydrogen detachment from the o-phenylendiamine moiety, is demonstrated under an N2 atmosphere. [ABSTRACT FROM AUTHOR]

Zeolites are usually synthesized by hydrothermal reactions using monomeric or polymeric Al- and Si-containing precursors, whereas simple and direct routes for the rational synthesis of zeolites remain elusive. In this work, we demonstrate the synthesis of the two zeolites L (LTL type) and W (MER type) from a single molecular precursor (MP), (PyH)[Al{Ph2Si(OSiPh2O)2}2] (AlSi6; PyH = pyridinium cation), under hydrothermal conditions using KOH as the only additive. Under acidic conditions, the heptanuclear structure of AlSi6 is hydrolyzed without cleavage of the Si–Ph bonds, while the hydrothermal reaction under basic conditions allows the crystallization of zeolites under concomitant Si–Ph cleavage. X-ray diffraction and scanning electron microscopy studies revealed that zeolite L, which exhibits a cylindrical morphology, was produced selectively by hydrothermal treatment of AlSi6 at 160–200 °C in the presence of KOH (3 eq.). In contrast, increasing the amount of KOH (from 6 to 12 eq.) resulted in the formation of zeolite W with a twin-ball morphology. The specific surface area and Si/Al ratios of the synthesized zeolites L and W are comparable to those previously reported. These experimental results suggest promising potential of structurally and compositionally well-defined MPs, including even those with organic functional groups, for the construction of zeolites. [ABSTRACT FROM AUTHOR]

The global demand for energy and the concerns over climate issues renders the development of alternative renewable energy sources such as hydrogen (H2) important. A high‐spin (hs) FeII complex with o‐phenylenediamine (opda) ligands, [FeII(opda)3]2+ (hs‐[6R]2+), was reported showing photochemical H2 evolution. In addition, a low‐spin (ls) [FeII(bqdi)3]2+ (bqdi: o‐benzoquinodiimine) (ls‐[0R]2+) formation by O2 oxidation of hs‐[6R]2+, accompanied by ligand‐based six‐proton and six‐electron transfer, revealed the potential of the complex with redox‐active ligands as a novel multiple‐proton and ‐electron storage material, albeit that the mechanism has not yet been understood. This paper reports that the oxidized ls‐[0R][PF6]2 can be reduced by hydrazine giving ls‐[FeII(opda)(bqdi)2][PF6]2 (ls‐[2R][PF6]2) and ls‐[FeII(opda)2(bqdi)][PF6]2 (ls‐[4R][PF6]2) with localized ligand‐based proton‐coupled mixed‐valence (LPMV) states. The first isolation and characterization of the key intermediates with LPMV states offer unprecedented molecular insights into the design of photoresponsive molecule‐based hydrogen‐storage materials. [ABSTRACT FROM AUTHOR]

Functionalization of a cobalt/dioxolene complex with branched, asymmetric alkyl chains promotes non-cooperative and cooperative valence tautomerisms synchronized with thermodynamically favoured crystal-to-melt and kinetically generated glass-to-melt phase transitions, respectively, depending on the degree of crystallinity. [ABSTRACT FROM AUTHOR]

A novel alkyl chain-functionalized manganese complex with dioxolene ligands shows a bimodal three-membered valence tautomerism, one of which synchronizes with a cooperative solid–melt phase transition and the other occurs in the melt noncooperatively. [ABSTRACT FROM AUTHOR]

Abstract: Invited for the cover of this issue is the group of Ho‐Chol Chang from Chuo University, Tokyo, Japan. The cover image shows the effect of ligand substitution on the electronic properties of the [Mo6S8] cluster core. [ABSTRACT FROM AUTHOR]

Abstract: The combination of the redox‐active mesogenic anion [NiII(Bdt)(BdtSQ)]− (Bdt=1,2‐benzenedithiolato; BdtSQ=1,2‐dithia‐semi‐benzoquinonato) with alkyl‐substituted ammonium cations afforded a series of redox‐active ionic complexes of the type [NR4][NiII(Bdt)(BdtSQ)] [R=nC16H33 (NC164Ni) and C8,10 (NC8,104Ni); C8,10=6‐octylhexadecyl] or [NMe2R2][NiII(Bdt)(BdtSQ)] [R=nC16H33 (NMe2C162Ni) and C8,10 (NMe2C8,102Ni)]. X‐ray crystallographic analyses of NMe2C162Ni and NC164Ni revealed the formation of cation‐dependent integrated ionic layers separated by interdigittated alkyl chains. Complexes NMe2C162Ni and NC164Ni commonly form crystalline phases at room temperature, whereas complexes NMe2C8,102Ni and NC8,104Ni, which contain branched alkyl chains, form a metastable mesophase and an amorphous phase at the same temperature, respectively. Furthermore, complexes NMe2C162Ni, NMe2C8,102Ni, and NC164Ni commonly form a smectic A phase (SmA) at 375, 317, and 342 K, respectively. For the four complexes, well‐defined cyclic voltammetry responses, derived from ligand‐based oxidation and reduction, were observed in solution and the condensed phases, that is, upon casting these complexes on an indium‐doped tin oxide working electrode. The present study demonstrates the tunability of the mesomorphism of ionic molecular assemblies composed of alkyl‐substituted quaternary ammonium cations, while maintaining the well‐defined redox responses of the anions even in the condensed phases. [ABSTRACT FROM AUTHOR]

The reaction of N,N'-bis(diisopropylphosphoniumacetyl)-o-phenylenediamide dibromide (H4L⋅2Br) with NiII[ClO4]⋅ 6H2O in the presence of Et3N resulted in the formation of N,N'-bis(diisopropylphosphinoacetyl)-o-phenylenediamidate nickel(II) ([NiII(L)]). The single-crystal X-ray diffraction analysis of [NiII(L)] revealed that each pair of N and P atoms in L2- coordinates in a tetradentate fashion to afford a distorted squareplanar NiII amide complex. On the other hand, N,N'-bis(diisopropylphosphinoacetyl)-o-phenylenediamide copper(I) bromide ([CuI(H2L)Br]) was isolated by the reaction of H4L⋅2Br with [CuI(MeCN)4][PF6] in the presence of Et3N. The structural analysis revealed that the two P atoms in H2L coordinate in a bidentate fashion to afford a trigonal-planar CuI complex, in which the amide moieties remain in free form. Complex [NiII(L)] showed reversible deprotonation processes on the amidate ligand (L2-), whereas the protonated state of the N atoms of the amide ligand (H2L) in [CuI(H2L)Br] was maintained, even in the presence of excess Et3N, suggesting substantial stability for the protonated state. [ABSTRACT FROM AUTHOR]

The design of redox-active metal-organic frameworks and coordination networks (CNs), which exhibit metal- and/or ligand-centered redox activity, has recently received increased attention. In this study, the redox-active metalloligand (RML) [Me4N]3 fac-[CrIII(mp)3] ( 1) (mp=2-mercaptophenolato) was synthesized and characterized by single-crystal X-ray diffraction analysis, and its reversible ligand-centered one-electron oxidation was examined by cyclic voltammetry and spectroelectrochemical measurements. Since complex 1 contains O/S coordination sites in three directions, complexation with K+ ions led to the formation of the two-dimensional honeycomb sheet-structured [K3 fac-{CrIII(mp)3}(H2O)6] n ( 2⋅6 H2O), which is the first example of a redox-active CN constructed from a RML with o-disubstituted benzene ligands. Herein, we unambiguously demonstrate the ligand-centered redox activity of the RML within the CN 2⋅6 H2O in the solid state. [ABSTRACT FROM AUTHOR]

Chemical one-electron oxidation of [PtII(3,5-DTBCat)(DTBbpy)] (1) (3,5-DTBCat = 3,5-di-tert-butyl catecholato, DTBbpy = 4,4′-di-tert-butyl-2,2′-bipyridine) afforded the corresponding paramagnetic complex, [PtII(3,5-DTBSQ)(DTBbpy)]+PF6− (1(PF6)), as a result of ligand-centred oxidation. While complex 1 is relatively stable in common organic solvents, the present study demonstrates that cationic [1]+ is subject to an unprecedented solvent-induced disproportionation in highly polar solvents such as DMSO and DMF, which results in the formation of 1 and a free benzoquinone. [ABSTRACT FROM AUTHOR]

A novel platinum(II)-diimine complex, [Pt(CN)2(H2dcphen)] ( 1; H2dcphen=4,7-dicarboxy-1,10- phenanthroline), was synthesized and its vapochromic shape-memory behavior was evaluated. The as-synthesized amorphous purple solid, [Pt(CN)2(H2dcphen)]⋅2 H2O ( 1 P), exhibited vapochromic behavior in the presence of alcoholic vapors through transformation to a red, crystalline, porous, vapor-adsorbed form, 1 R⊃vapor. The obtained 1 R⊃vapor complex released the adsorbed vapors upon heating without collapse of the porous structure. The vaporfree, porous 1 R⊃open could detect water or n-hexane vapor, although these vapors could not induce 1 P-to- 1 R⊃vapor transformation, and 1 R⊃open could easily be converted to the initial 1 P by manual grinding. These results indicate that 1 is a new shape-memory material that functions through formation and collapse of the porous framework with an emission change upon vapor-adsorption and grinding; this enables it to exhibit vapor history and ON-OFF switching sensing functions. [ABSTRACT FROM AUTHOR]

The redox-active metalloligand (RML) (Et3NH)3[CrIII(F4Cat)3] (F4Cat = perfluorocatecholato) (1) was synthesized and its interactions with guest metal ions Li+, Mn2+, Fe2+, Co2+, Cu2+, and Zn2+ were examined. Cyclic voltammetry measurements and spectroelectrochemical studies revealed that complex 1 shows three-step ligand-centred one-electron oxidation to consecutively generate [CrIII(F4Cat)2(F4SQ)]2− (F4SQ = perfluorosemiquinonato), [CrIII(F4Cat)(F4SQ)2]−, and [CrIII(F4SQ)3] at −0.12, 0.23, and 0.53 V vs. Ag/Ag+ in dichloromethane, or at −0.21, 0.08, and 0.50 V in acetonitrile (MeCN), respectively. Titration experiments in MeCN revealed that treatment of 1 with Cu2+ leads to the formation of [CrIII(F4Cat)2(F4SQ)]2− and Cu+via a redox reaction. However, when 1 was treated with Li+, Mn2+, Fe2+, Co2+, and Zn2+, further titration experiments revealed that these metal ions coordinated via the lone pairs on the coordinating oxygen atoms of the F4Cat2− moieties in a one-to-one ratio, and binding constants of 3.7 (±0.3) × 104 (Li+), 1.5 (±0.2) × 105 (Mn2+), 2.2 (±0.4) × 105 (Fe2+), 1.9 (±0.2) × 105 (Co2+), and 3.8 (±0.4) × 105 M−1 (Zn2+) were established. Moreover, the oxidation potentials of 1 were positively shifted by 0.08–0.33 V upon addition of guest metal ions. Spectroelectrochemical studies of 1 in the presence of guest metal ions suggested that ligand-centred one- and two-electron oxidation of the RML occurred for Li+, Mn2+, Co2+, and Zn2+, respectively, while guest metal-centred one-electron oxidation was observed for Fe2+. Considering all the aforementioned results, this study demonstrated for the first time the ability of [CrIII(F4Cat)3]3− to act as a RML in solution. [ABSTRACT FROM AUTHOR]

The introduction of a Au(iii) ion into a mesogenic core, [M(Bdt)(Cnbpy)]+ (Bdt = 1,2-benzenedithiolato and Cnbpy = 4,4′-di-alkyl-2,2′-bipyridine (n = 13 (4,4′-di-tridecyl-2,2′-bipyridine (C13bpy)) and 8,10 (4,4′-di-(3-octyltridecyl)-2,2′-bipyridine (C8,10bpy)))), leads to the formation of ionic molecular assemblies in crystalline and mesophases. Successive syntheses of precursor complexes, [AuCl2(Cnbpy)]PF6 (n = 13 (1) and 8,10 (2)), followed by the target complexes, [Au(Bdt)(Cnbpy)]PF6 (n = 13 (3) and 8,10 (4)), were achieved. The crystallographic analysis of 3 revealed that the central cationic cores form a characteristic one-dimensional columnar structure, which is an essential property for the formation of columnar structures in the liquid crystalline phase. The central cores of the [Au(Bdt)(C13bpy)]+ cations in 3 stack alternatively so as to cancel out their dipole moments and the counteranions lie between the cationic columns. Furthermore, the introduction of the branched alkyl tails in 4 induces the formation of a rectangular columnar liquid crystalline phase (Colr) with C2/m symmetry, and it melts to an isotropic liquid at 69 °C. The Colr phase of 4 is partially similar in its liquid crystalline structure to the neutral [Pt(Bdt)(C8,10bpy)] liquid crystal in a hexagonal columnar phase reported previously, while complex 4 shows a lower clearing point than that of the Pt analogue. Based on these results, the present study demonstrates the designability of the liquid crystalline structures of the [M(Bdt)(C8,10bpy)] skeleton together with their assembled structures and physico-chemical properties. [ABSTRACT FROM AUTHOR]

Cobalt, crystal engineering, N,O ligands, phase transitions, valence isomerization Keywords: cobalt; crystal engineering; N,O ligands; phase transitions; valence isomerization EN cobalt crystal engineering N,O ligands phase transitions valence isomerization 16272 16272 1 12/01/21 20211125 NES 211125 B Changing the length b of the side chains in a series of cobalt complexes changed the melting temperature and allowed the synchronicity of the valence tautomerism and solid-liquid transition to be controlled. Cover Feature: Tunable Synchronicity of Molecular Valence Tautomerism with Macroscopic Solid-Liquid Transition by Molecular Lattice Engineering (Chem. Eur. J. 66/2021). [Extracted from the article]

The presence of lone pairs on the Pt and S atoms of [Pt(Bdt)(DTBbpy)] ( l ) (Bdt = 1,2-benzenedithiolato and DTBbpy = 4,4'-di-ferf-butyl-2,2'-bipyridine) and [Pt(Bdt)(C13bpy)] (2) (C13bpy = 4,4'-ditridecyl-2,2'-bipyridine) led to selective dative bond formation with Cd(II). Complexes 1 and 2 show no binding interaction with Zn(II), while they bind selectively with Cd(ll) to give a twisted trinuclear complex, [Cd{Pt(Bdt)(DTBbpy)}2(ClO4)(H2O)]- (ClO4) (3), and a shuttiecock-shaped tetranuclear complex, [Cd{Pt(Bdt)(C13bpy)}3(H2O)](ClO4)2-CH2Cl2 (4), respectively, depending upon the alkyl groups substituted on the 2,2'-bipyridine. The two platinum moieties in 3 are connected to the seven-coordinated Cd atom through Pt →Cd (2.7331(7) and 2.7936(7) Å) and S → Cd (2.690(3), 2.940(3), and 3.067(3) A) dative bonds, while the diree moieties in 4 are connected to the tetrahedral Cd atom only by S → Cd (2.552(4) A) dative bonds. These structural variations found in 3 and 4 are caused not only by steric hindrance of the t-Bu groups but also by the microsegregation effect derived from the tridecyl chains. The three platinum moieties in 4 align so as to form a parallel orientation of their dipole moments, in contrast to the twisted arrangement found in 3. The dative bonds formed in 3 and 4 are commonly stable in the solid state and in less coordinative solvents such as dichloromethane, while dissociation behavior of platinum moieties with Cd(II) was observed in more coordinative THF. UV--vis and NMR spectroscopy unsealed the characteristic association/dissociation properties depending on the coordination abilities of solvents. Finally, the present study revealed that the formation of dative bonds between the platinum moieties with Cd(II) plays important roles not only in stabilizing the ground states, which leads to blue shifts in both absorption and emission energies, but also in electronic interactions between the moieties, which are revealed by electrochemical studies. [ABSTRACT FROM AUTHOR]

Four new bimetallic coordination polymers (CPs), {M[Pt(CN)2(5,5′-dcbpy)]·4H2O}n(M = Mg2+, Ca2+, Sr2+, Ba2+; 5,5′-H2dcbpy = 5,5′-dicarboxy-2,2′-bipyridine) were synthesized using four alkaline-earth metal ions and a Pt(ii)-diimine metalloligand [Pt(CN)2(5,5′-H2dcbpy)]. All four CPs are isomorphous with the Zn complex, {Zn[Pt(CN)2(5,5′-dcbpy)]·4H2O}n, which exhibits effective metallophilic interactions between Pt(ii) ions. These CPs exhibited colourful thermochromic behaviour and solid-state solvatochromic-like behaviours when suspended in various solvents. Thermogravimetric analysis and vapour-adsorption measurements revealed that the CPs can reversibly adsorb water and MeOH vapours. The emission energy of the triplet metal-metal-to-ligand charge-transfer (3MMLCT) state varied markedly upon guest adsorption/desorption. The chromic and vapour-adsorption properties of these CPs depend strongly on the cross-linking M2+ions. [ABSTRACT FROM AUTHOR]

We synthesized a thiosemicarbazone-functionalized flavin (Fl-(H)TSC: 2-[2-(3,4-dihydro-7,8-dimethyl-2,4-dioxobenzo[g]pteridin-10(2H)-yl)ethylidene]-hydrazinecarbothioamide) and its Pt(ii) complex [Pt(Fl-TSC)2], and characterized it using X-ray diffraction, UV–visible absorption and luminescence spectroscopy. X-ray structural analysis for [Pt(Fl-TSC)2] revealed that the structure of the isoalloxazine part was almost the same as that in lumiflavin (7,8,10-trimethylisoalloxazine), and the thiosemicarbazone moiety acted as a bidentate ligand to form a PtS2N2planar conformation. UV–visible absorption and luminescence spectra of these compounds were very similar to those of riboflavin, but the emission intensity and the lifetime decreased considerably. Theoretical calculations suggested that the charge-separated state (Fl−-TSC+) contributed to the faster quenching from the 1π–π* emission state. [ABSTRACT FROM AUTHOR]

Abstract: A zinc complex of biladienone forms a dimer in toluene and dichloromethane. Binding of two molecules of amino alcohols and diamines to the dimer occurs cooperatively, with the first binding constant being two orders or three orders of magnitude smaller than the second binding constant. Simple amines such as butylamine did not show such cooperative binding. We suggest the mechanism of cooperative binding, where the amino or hydroxyl group in amino alcohols or diamines prevents the dimer dissociation to result in the less tight binding for the first guest, while the binding of the second ligand caused dimer dissociation to release strain in the intermediate complex. [Copyright &y& Elsevier]

Syntheses and crystal structures of three new compounds {trans-[Cu(Hsal)2(4,4′-bipy)](DMF)}n (1), {cis-[Cu(Hsal)2(4,4′-bipy)](2H2O)}n (2), and [Cu2(Hsal)4(4,4′-bipy)]n (3) are reported. These three compounds have trans-, cis-, and dimer geometries bearing a common motif [Cu(Hsal)2(4,4-bipy)n] leading to ladder, zig-zag, and linear one-dimensional (1-D) networks, respectively. The Cu⋯Cu distances separated by 4,4′-bipy are different in these three compounds, which leads to an extension structure in compound 3 and a compact structure in compound 2. Conformations of 4,4′-bipy ligands in these three compounds are also different. In compound 1 there is stacking of the bidentate salicylate and the bridging salicylate from another molecule. There is also stacking of salicylate and 4,4′-bipy from another molecule in compound 2. [Copyright &y& Elsevier]

We report the direct observation of dioxygen molecules physisorbed in the nanochannels of a microporous copper coordination polymer by the MEM (maximum entropy method) /Rietveld method, using in situ high-resolution synchrotron x-ray powder diffraction measurements. The obtained MEM electron density revealed that van der Waals dimers of physisorbed O[sub2] locate in the middle of nanochannels and forma one-dimensional ladder structure aligned to the host channel structure. The observed O-O stretching Raman band and magnetic susceptibilities are characteristic of the confined O[sub2] molecules in one-dimensional nanochannels of CPL-1 (coordination polymer 1 with pillared layer structure). [ABSTRACT FROM AUTHOR]

Reactions of the Rh hydrido complex [Rh(H)2(PPh3)2(EtOH)2]ClO4 (1) with nitrogen ligands such as 2-(4-thiazolyl)benzimidazole (tbz), pyridazine (pdz), imidazole (im) and pyrimidine (pmd) in CH2Cl2 afforded various mononuclear Rh hydrido complexes, [Rh(H)2(PPh3)2(tbz)]ClO4 (2), [Rh(H)2(PPh3)2(pdz)2]ClO4·2CH2Cl2 (3), [Rh(H)Cl(PPh3)2(pdz)2]ClO4·CH2Cl2 (4), [Rh(H)2(PPh3)2(im)2]ClO4·2CH2Cl2 (5), [Rh(H)Cl(PPh3)2(im)2]ClO4·CH2Cl2 (6), [Rh(H)2(PPh3)2(pmd)2]ClO4·CH2Cl2 (7) and the Rh non-hydrido complex [RhCl2(pmd)4]ClO4 (8). The Rh complexes 2, 3, 5 and 6 were crystallographically characterized. The formation process was monitored by 1H NMR and UV–Vis spectra. In all the Rh hydrido complexes, the Rh atom is coordinated by two PPh3 ligands in trans-positions and two nitrogen ligands in the cis-positions. The remaining sites are occupied by one or two hydride atoms to form a saturated 18-electron framework in a slightly distorted octahedral geometry. For complex 2 an appreciable inter-molecular π interaction is observed between planes of tbz and PPh3 ligands, while an intra-molecular hydrogen bonding interaction between C&z.sbnd;H and Cl atoms is found in complex 6. [Copyright &y& Elsevier]

Keywords: iron; N ligands; oxidation; reduction; valency EN iron N ligands oxidation reduction valency 17283 17283 1 12/21/20 20201218 NES 201218 The authors wish to revise the original title with a correction shown below. The authors offer their apologies for the mistake and for any inconvenience to the readers. Iron, N ligands, oxidation, reduction, valency. [Extracted from the article]

We report the photochemical carboxylation of o-phenylenedimamine in the absence of a base and an electron donor under an atmosphere of CO2, which afforded 2,3-diaminobenzoic acid (DBA) in 28% synthetic yield and 0.22% quantum yield (Φ(%)). The synthetic yield of DBA in this reaction increased to 58% (Φ(%) = 0.47) in the presence of Fe(II). The photochemical reaction described in this work provides an effective strategy to use light as the driving force for the direct carboxylation of organic molecules by CO2. [ABSTRACT FROM AUTHOR]

A novel Pt(II)–diimine complex exhibits an interesting vapochromic shape‐memory behavior. The amorphous form is converted to a red luminescent vapor‐adsorbed form in the presence of alcoholic vapors. The vapor‐adsorbed form can release the vapors without collapse of the porous structure; this enables it to adsorb other vapors. The vapor‐free porous form can easily be converted to the initial amorphous form by manual grinding. These transformations enable the design of a new chemical sensor with vapor history and ON–OFF switching functions. More information can be found in the Full Paper by A. Kobayashi, M. Kato et al. on page 2682 ff. [ABSTRACT FROM AUTHOR]