Expression of concern: Valence tautomeric interconversion of bis-dioxolene cobalt complex with imino-pyridine functionalized by TEMPO moiety in solid solutions with isostructural nickel analogue: phase transitions and monocrystal destruction.

Expression of concern for 'Valence tautomeric interconversion of bis-dioxolene cobalt complex with imino-pyridine functionalized by TEMPO moiety in solid solutions with isostructural nickel analogue: phase transitions and monocrystal destruction' by Michael P. Bubnov , , 2024, , 9151-9160, https://doi.org/10.

Hydro-coupling of isocyanates promoted by 1,2-bis(arylimino)acenaphthene aluminum hydrides.

The interaction of aluminum hydrides [(dpp-bian)AlH] (1) and [(Ar-bian)AlH(THF)] (2) (dpp-bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene; Ar-bian = 1,2-bis[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene) with isocyanates RNCO (R = Ph, Cy, 3,5-ClPh) proceeds insertion of two molecules of isocyanates into each Al-H bond with the formation of unique Al carboxamides [(Ar-bian)Al{OC(H)N(R)C(NR)O}] (Ar = dpp, R = Ph, 3; Ar = Ar, R = Ph, 4; Ar = Ar, R = Cy, 5; Ar = Ar, R = 3,5-ClCH, 6). In contrast, the reactions of 1 and 2 with an excess of -butylisocyanate afford formimidate derivatives [(Ar-bian)Al{OC(H)N(Bu)}] (Ar = dpp, 7; Ar = Ar, 8). The reactions of ,'-dicyclohexylcarbodiimide with 1 and 2 give [(dpp-bian)Al{(NCy)CH}] (9) and [(Ar-bian)Al(H){(NCy)CH}] (10), correspondingly.

Valence tautomeric interconversion of bis-dioxolene cobalt complex with imino-pyridine functionalized by TEMPO moiety in solid solutions with isostructural nickel analogue: phase transitions and monocrystal destruction.

Valence tautomeric complexes (VT) are promising systems for creating molecular devices. From this viewpoint, valence tautomeric complexes with a hysteresis loop on the magnetic curve are of special interest as potential memory elements. The hysteresis loop is a consequence of retarded structural rearrangements which investigation is an actual problem.

Gradual solid-state redox-isomerism in the lanthanide series.

Oxidation of [(Ar-bian)Yb(dme)] (1) (Ar-bian = 1,2-bis[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene; dme = 1,2-dimethoxyethane) by 0.5 equivalent of MeNC(S)S-S(S)CNMe in dme at ambient temperature affords a mixture of two products, [(Ar-bian)Yb{SC(S)NMe}(dme)] and [(Ar-bian)Yb{SC(S)NMe}(dme)], which represent two redox-isomers (2a and 2b, respectively). Their ratio in solution depends on the solvent as well as on the temperature.

Diversity of transformation of heteroallenes on acenaphthene-1,2-diimine aluminum oxide.

The reactions of oxide [(dpp-bian)Al(μ-O)Al(dpp-bian)] (1) (dpp-bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) with phenyl- or cyclohexylisocyanates result in the formation of carbonimidate derivatives [(dpp-bian)Al(μ-O)(μ-RNCO)Al(dpp-bian)] (R = Ph, 2; Cy, 3). Addition of ,'-dicyclohexylcarbodiimide to compound 1 leads to the formation of ureate complex [(dpp-bian)Al(μ-O)(μ-(CyN)CO)Al(dpp-bian)] (4). The reactions of the oxide 1 with pinacolborane and catecholborane afford oxo-bridged hydride [{(dpp-bian)Al(H)}(μ-O){Al(OBpin)(dpp-bian)}] (5) and compound [{(dpp-bian)Al(OBCat)}(μ-O)] (7), respectively.

Lanthanide Coordination Polymers with Soft-Base Ditopic Bisthiazolate Ligands.

In order to prepare the first lanthanide coordination polymers (CPs) based on ditopic sulfide ligands, benzo[1,2-:4,5-']bisthiazole-2,6(3,7)-dithione (HL) was used as a linker. The reactions of lanthanide silylamides Ln[N(SiMe)] (Ln = Nd, Gd, Er, and Yb) with HL result in the formation of soluble dimethyl sulfoxide (DMSO) ionic salts [Ln(DMSO)][L] [Ln = Nd (), Gd (), Er (), and Yb ()]. Due to the lack of coordination of anionic ligands, compounds , , and do not show sensitized metal-centered photoluminescence (PL), while Gd compound shows weak phosphorescence at 77 K.

Praseodymium Metallacrown-Based NMR Probe for Enantioselective Discrimination of Mandelate Anions in Water.

Recently, the enhanced interest in water-soluble aminohydroximate Ln(III)-Cu(II) metallacrowns (MC) is largely due to their fascinating structural chemistry, diverse properties and ease of synthesis. We examined the water-soluble praseodymium(III) alaninehydroximate complex Pr(HO)[15-MC-5]·3Cl () as a highly effective chiral lanthanide shift reagent for NMR analysis of the biologically relevant (R/S)-mandelate (MA) anions in aqueous media. The R-MA and S-MA enantiomers can be easily discriminated in the presence of small (1.

3 a,6 a-Diaza-1,4-Diphosphapentalenes: Synthesis and Complexation with the Organic π-Acceptor 1,2,4,5-Tetracyanobenzene.

The reaction of PCl with diethyl ketazine and 4-phenylcyclohexanone azine results in the formation of 1,4-dichloro-3a,6a-diaza-1,4-diphosphapentalenes which were reduced by magnesium in THF to give corresponding diazadiphosphapentalenes EtMeDDP and PhcHexDDP, containing two-coordinate phosphorus atoms. According to the CVA data, the new diazadiphosphapentalenes are strong electron donors showing oxidation peak potentials at 0.34 and 0.

Synthesis and Antimicrobial Activity of Sulfenimines Based on Pinane Hydroxythiols.

The widespread presence of multidrug-resistant pathogenic microorganisms challenges the development of novel chemotype antimicrobials, insensitive to microbial tools of resistance. To date, various monoterpenoids have been shown as potential antimicrobials. Among many classes of molecules with antimicrobial activity, terpenes and terpenoids are an attractive basis for the design of antimicrobials because of their low toxicity and availability for various modifications.

Synthesis of Trifluoromethylated Monoterpene Amino Alcohols.

For the first time, monoterpene trifluoromethylated β-hydroxy-benzyl--oximes were synthesized in 81-95% yields by nucleophilic addition of the Ruppert-Prakash reagent (TMSCF) to the corresponding β-keto-benzyl--oximes based on (+)-nopinone, (-)-verbanone and (+)-camphoroquinone. Trifluoromethylation has been determined to entirely proceed chemo- and stereoselective at the C=O rather than C=N bond. Trifluoromethylated benzyl--oximes were reduced to the corresponding α-trifluoromethyl-β-amino alcohols in 82-88% yields.

Synthesis and Biological Activity of Unsymmetrical Monoterpenylhetaryl Disulfides.

New unsymmetrical monoterpenylhetaryl disulfides based on heterocyclic disulfides and monoterpene thiols were synthesized for the first time in 48-88% yields. Hydrolysis of disulfides with fragments of methyl esters of 2-mercaptonicotinic acid was carried out in 73-95% yields. The obtained compounds were evaluated for antioxidant, antibacterial, antifungal activity, cytotoxicity and mutagenicity.

Reduction of CO with Aluminum Hydrides Supported with Ar-BIAN Radical-Anions (Ar-BIAN = 1,2-Bis(arylimino)acenaphthene).

The reactions of HAlCl with [(dpp-Bian)Na(EtO)] and [(Ar-Bian)Na(THF)] produce respective aluminum hydrides supported by radical-anionic 1,2-bis(arylimino)acenaphthene ligands, [(dpp-Bian)AlH] ( and [(Ar-Bian)AlH(THF)] () (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene); Ar-Bian = 1,2-bis[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene). The reaction of with CO proceeds with reduction of both C═O bonds and results in diolate [{(dpp-Bian)Al(μ-OCH)}] (). Complex reacts with CO to carbonate [{(Ar-Bian)Al(μ-OCHOCO)}] () that is a result of the insertion of CO into the Al-O bond in diolate species formed initially.

Novel Oxidovanadium Complexes with Redox-Active R-Mian and R-Bian Ligands: Synthesis, Structure, Redox and Catalytic Properties.

A new monoiminoacenaphthenone 3,5-(CF)CH-mian (complex ) was synthesized and further exploited, along with the already known monoiminoacenaphthenone dpp-mian, to obtain oxidovanadium(IV) complexes [VOCl(dpp-mian)(CHCN)] () and [VOCl(3,5-(CF)CH-bian)(HO)][VOCl(3,5-(CF)CH-bian)]·2.85DME () from [VOCl(CHCN)(HO)] () or [VCl(THF)]. The structure of all compounds was determined using X-ray structural analysis.

Interaction of dicoordinate phosphorus with boranes: chemistry of 3a,6a-diaza-1,4-diphosphapentalene as masked phosphinidene.

Treatment of 3a,6a-diaza-1,4-diphosphapentalene (DDP) with an excess of PhBCl2 yields the corresponding bis(borane) adduct DDP(PhBCl2)2 (14), demonstrating the availability of two lone pairs on the phosphorus center. The reaction between DDP and B(C6F5)3 yields (1 : 1) phosphino-borane complex 16. The free lone electron pair on the pyramidal P atom in 16 participates in the intramolecular non-covalent interactions P(1)F(1) and P(1)F(6) giving additional 3.

Metal-Organic Frameworks Derived from Calcium and Strontium Complexes of a Redox-Active Ligand.

The reactions of monomeric [(dpp-Bian)M(thf)] (M = Ca (), Sr (); dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) with 4,4'-bipyridyl (4,4'-bipy) proceed with electron transfer from dpp-Bian to 4,4'-bipy to afford calcium and strontium complexes containing simultaneously radical-anionic dpp-Bian and 4,4'-bipy ligands. In tetrahydrofuran (thf) the reactions result in 1D coordination polymers [{(dpp-Bian)M(4,4'-bipy)(thf)}·4thf] (M = Ca (), Sr ()), while in a thf/benzene mixture the reaction between and 4,4'-bipy affords the 2D metal-organic framework [{(dpp-Bian)Ca(4,4'-bipy)}·2thf·2CH] (). The structures of compounds , and have been determined by single-crystal X-ray analyses.

Single Crystal X-ray Diffraction Studies of Two Polymorphic Modifications of the Dicarbonyl--Semiquinonato Rhodium Complex at Different Temperatures. Destruction Stimulated by Cooling Versus Stability.

It was found that the dicarbonyl-rhodium--semiquinonate complex (which thread-like crystals can bend reversibly under light/warm activation) can form two polymorphic modifications: isometric prisms () and sticks (). Some thin sticks can bend as mentioned above. X-ray diffraction studies of polymorphic modifications at different temperatures were carried out.

Water-Soluble Bismuth(III) Polynuclear Tyrosinehydroximate Metallamacrocyclic Complex: Structural Parallels to Lanthanide Metallacrowns.

Recently there has been a great deal of interest and associated research into aspects of the coordination chemistry of lanthanides and bismuth-elements that show intriguing common features. This work focuses on the synthesis and characterization of a novel bismuth(III) polynuclear metallamacrocyclic complex derived from aminohydroxamic acid, in order to compare the coordination ability of Bi with the similarly sized La ions. A polynuclear tyrosinehydroximate Bi(OH)[15-MC-5](NO) () was obtained according to the synthetic routes previously described for water-soluble Ln(III)-Cu(II) 15-MC-5 metallacrowns.

Imine-Based Catechols and -Benzoquinones: Synthesis, Structure, and Features of Redox Behavior.

Novel sterically hindered catechols of the type 3-(RN=CH)-4,6-DBCatH with iminoalkyl or iminoaryl groups in the third position of the aromatic ring have been synthesized and characterized in detail. The -benzoquinones 3-(RN=CH)-4,6-DBBQ have been synthesized by the oxidation of the corresponding catechols. The oxidation of methylimino-substituted catechol with K[Fe(CN)] in alkaline medium leads to the formation of two products: -quinone and diene-dione, the product of the water addition to the corresponding -quinone.

Dual Reactivity of 3a,6a-Diaza-1,4-diphosphapentalene: π-Donor versus n-Donor.

Herein, we present the synthesis, single-crystal X-ray structures, and spectroscopic properties for the 1:1 donor-acceptor complexes of 1,2,4,5-tetracyanobenzene (TCNB) with annelated 3a,6a-diaza-1,4-diphosphapentalenes (DDPs) based on cyclohexanone azine () and tetralone azine (). These are the first complexes of an organic π-acceptor with donor phosphorus heterocycles. According to the X-ray study, the DDPs and TCNB molecules are alternately stacked with interplanar distances of 3.

Cerium(iii) complexes with azolyl-substituted thiophenolate ligands: synthesis, structure and red luminescence.

In order to obtain molecular Ce(iii) complexes which emit red light by f-d transitions the azolyl-substituted thiophenolates were used as the ligands. The thiophenolate Ce(iii) complexes were synthesized by the reaction of Ce[N(SiMe)] with respective thiophenols 2-(2'-mercaptophenyl)benzimidazole (H(NSN)), 2-(2'-mercaptophenyl)benzoxazole (H(OSN)) and 2-(2'-mercaptophenyl)benzothiazole (H(SSN)) in DME media. The structures of the benzimidazolate (Ce(NSN)(DME)) and benzothiazolate (Ce(SSN)(DME)) derivatives were determined by X-ray analysis which revealed that the cerium ion in the molecules is coordinated by one DME and three anionic thiophenolate ligands.

Features of the Molecular Structure and Luminescence of Rare-Earth Metal Complexes with Perfluorinated (Benzothiazolyl)phenolate Ligands.

A set of Sc, Nd, Sm, Eu, Ho, Gd, Er, Yb complexes with perfluorinated 2-(benzothiazol-2-yl)phenolate ligands Ln(SON)(DME) were synthesized by the reactions of silylamides Ln[N(SiMe)] with phenol H(SON). The structure of the initial phenol, Sc, and Er complexes was established using X-ray analysis, which revealed that the obtained compounds are mononuclear, in contrast to the binuclear non-fluorinated analogues [Ln(SON)] synthesized earlier. All the obtained complexes, both in solid state and in tetrahydrofuran (THF) solutions, upon excitation by light with λ 395 or 405 nm show intense luminance of the ligands at 440-470 nm.

Synthesis, structure and long-lived NIR luminescence of lanthanide ate complexes with perfluorinated 2-mercaptobenzothiazole.

To obtain new efficient lanthanide-based NIR luminophores perfluorinated 2-mercaptobenzothiazole was used as a ligand. The ate-complexes [(Ln(mbtF)4)-(Na(DME)3)+] of Nd (1), Sm (2), Tb (3), Er (4), Yb (5) and [(Y(mbtF)4)-(Li(DME)3)+] (6) were synthesized in high yields by the reactions of the respective silylamide compounds Ln[N(SiMe3)2]3 and M[N(SiMe3)2] (M = Li, Na) with 4,5,6,7-tetrafluoro-1,3-benzothiazol-2(3H)-thione (HmbtF) in DME media. The complexes 1-3 and 6 were structurally characterized by X-ray diffraction analysis.

One-Electron Reduction of 2-Mono(2,6-diisopropylphenylimino)acenaphthene-1-one (dpp-mian).

The electrochemical characteristics of 2-mono(2,6-diisopropylphenylimino)acenaphthene-1-one (dpp-mian) have been investigated. One-electron reduction of dpp-mian involves the iminoketone fragment, which is revealed by the EPR spectrum obtained after the electrolysis of the dpp-mian solution in tetrahydrofuran (THF). The reduction of dpp-mian with one equivalent of metallic potassium leads to a similar EPR spectrum.

Valence-Tautomeric Interconversion in a Bis(dioxolene)cobalt Complex with Iminopyridine Functionalized by a TEMPO Moiety. Phase Transition Coupled with Monocrystal Destruction.

Iminopyridine modified by TEMPO nitroxide was utilized for the synthesis of an octahedral bis(o-semiquinonato)cobalt complex. Variable-temperature magnetic susceptibility measurements detect a valence tautomeric transformation in the temperature range 200-300 K. A reproducible hysteresis loop of about 40 K width is observed on the magnetic moment temperature dependence in the transition region.

Sensitization of NIR luminescence of Yb by Zn chromophores in heterometallic complexes with a bridging Schiff-base ligand.

Herein, complexes [ZnL] (1), {(HO)Zn(μ-L)Yb[OCH(CF)]} (2), {[(CF)HCO]Zn(μ-L)Yb[OCH(CF)](μ-OH)} (3), and [(HO)Ln(L)] (Ln = Yb (4) and Gd (5)) containing a bridging Schiff-base ligand (HL = N,N'-bis(3-methoxy salicylidene)phenylene-1,2-diamine) were synthesized. The compounds 1-4 were structurally characterized. The ytterbium derivatives 2-4 exhibited bright NIR metal-centred photoluminescence (PL) of Yb ion under one- (λ = 380 nm) and two-photon (λ = 750 nm) excitation.