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The isolable bis(tetramethylaluminate) lanthanide complexes [2-R2,6-XC6H4NC(tBu)(2,6-R12C6H3)]Ln(AlMe4)2 (R1 = R2 = X = Me, Ln = La (1); R1 = R2 = X = Me, Ln = Nd (2); R1 = iPr, R2 = H, X = OMe, Ln...

The outcome of salt metathesis reactions between the equimolar amounts of LnCl3 and dimeric potassium diphenylmethanide {[2,2′-(4-MeC6H3NMe2)2CH]K(THF)}2 depends on the rare-earth metal ion. In the case of ScIII and YIII, the reactions afford chlorido-bis(diphenylmethanido) complexes {[2,2′-(4-MeC6H3NMe2)2CH]2LnIII(μ-Cl)}2, in which the diphenylmethanido ligands perform bidentate κ2-CN coordination according to the X-ray data. For YbIII and SmIII, these reactions result in the spontaneous reduction of LnIII to LnII and the formation of known bis(diphenylmethanido) complexes [2,2′-(4-MeC6H3NMe2)2CH]2LnII and the product of oxidative coupling of diphenylmethanido anions.

N-Heterocyclic carbene is a versatile ligand for the preparation of copper( i ) and silver( i ) derivatives bearing the radical anion forms of redox active o-benzoquinone and o-iminobenzoquinone. The paramagnetic three-coordinated copper( i ) and silver( i ) o-benzosemiquinone and o-iminobenzosemiquinone complexes were prepared and characterized by EPR spectroscopy and X-ray diffraction analysis.

Sm, Er, and Yb complexes containing anionic (4,5,6,7-tetrafluorobenzothiazol-2-yl)-2-(3,4,5,6-tetrafluoro)phenolate (SONF) and 3-(2-benzothiazol-2-yl)-2-naphtholate (NpSON) and neutral 1,10-phenathroline or 2,2'-bipyridine ligands were synthesized. The structures of complexes Yb(SONF)2-(NpSON)(DME)1.5 (II) and previously synthesized Er(SONF)3(DME) (I) were determined by X-ray diffraction (CIF files CCDC nos. 1972769 and 1972770, respectively). Upon excitation by light at λ 405 nm, all complexes showed luminescence of the ligands and Ln3+ ions. The OLED devices based on samarium complexes showed moderate intensi metal-centered emission of moderate intensity at a 19 V voltage.

The exchange reactions of equimolar amounts of potassium penta(benzyl)cyclopentadienide CpBn5K (CpBn5 = C5(CH2Ph)5) and SmI2(THF)2 or YCl3 afforded the corresponding half-sandwich derivatives [CpBn5Sm(DME)(μ-I)]2 (1) and [CpBn5YCl2(THF)]2[KCl(THF)2] (2). According to the X-ray diffraction data, the metal ions in complexes 1 and 2 are coordinated by CpBn5 ligands in a η5-fashion. The difference is that there is a short contact between the SmII cation and one benzyl group of the cyclopentadienyl ligand in structure 1, whereas such interaction is absent in structure 2.

2,5-Dihydroxy-3,6-di-tert-butyl-p-benzoquinone (QtBuDiol) reacts with Ph3SbBr2 in toluene in the presence of triethylamine to yield the ionic complex [Et3NH]+[(DionetBuDiolate)SbPh3Br]– (I). The same reaction in methanol leads to complete displacement of bromide ions from the antimony coordination sphere and gives triphenylantimony(V) 1,2-diolate (DionetBuDiolate)SbPh3 · MeOH (II · MeOH). The molecular structure of the complexes was determined by X-ray diffraction (CIF files CCDC no. 1960681 (I · toluene) and 1960682 (II · 2MeOH)). Both complexes are characterized by quinoid bond distribution in the six-membered carbon rings and by C=O double bonds in the Ph3SbO2C6(t-Bu)2O2 moieties. Formally, the complexes can be considered as 3,6-di-tert-butyl-o-benzoquinone derivatives with the organometallic Ph3SbO2 group in positions 4 and 5 of the quinone ring. The electrochemical reduction of II · MeOH in dichloromethane occurs at E1/2 = –1.52 V, which is significantly shifted to the cathodic region relative to the data for 3,6-di-tert-butyl-o-benzoquinone (E1/2 = –0.51 V). This redox potential shift indicates a significant decrease in the electron-withdrawing properties of the o-quinoid moiety, which is caused by the effect of the electron-donating catecholate metallacycle.

In this article, we report on the results of experimental and theoretical (DFT calculation of an isolated molecule) investigation of electron density in a triphenylantimony disorbate complex (triphenylantimony bis(hexa-2,4-dienoate), Ph3Sb(O2CCH=CH–CH=CH–CH3)2 (1)). A topological analysis of the electron density was carried out in the framework of the quantum theory of atoms in molecules (QTAIM), which allows to study the nature of chemical bonds and the molecular graph in Ph3Sb(O2CCH=CH–CH=CH–CH3)2 complex. The molecular graph is an important tool for determining the interacting atoms. However, the molecular graph of the triphenylantimony disorbate complex did not show the presence of the “expected” intramolecular interactions between the antimony atom and the carbonyl oxygen one. Such a situation can be caused by electron density low curvature between these atoms. It is extremely difficult case, and sometimes it is not possible to find all the “expected” bond paths and critical points (3,−1). Thus, the molecular graph for this class of compounds does not provide a definitive picture of the chemical bonding and should be complemented with other descriptors, such as а source function (SF) and non-covalent interaction (NCI) index. It was found that in some cases using the SF on the NCI isosurface allows to interpret intramolecular interactions in the absence of a bond critical point more correctly. In this article, presence of intramolecular interaction in the absence of a bond critical point between the antimony atom and the carboxylate oxygen one was shown. The carboxylate fragment always acts as a source of the electron density for the Sb…O(carbonyl) interactions, whereas the antimony atom can be both a source and a sink for it.

The addition of different substituted o-benzoquinones and o-iminobenzoquinones to tin(II) bis(o-iminophenolates) of the types (Fc-IP)2SnII and (Fc-4,6-IP)2SnII (where Fc-IP is anion 2-(ferrocenylme...

New 10π-electron stabilized O,N-heterocyclic germylene was synthesized and structurally characterized for the first time. Its reduction with potassium in THF resulted in a unique low-valent germanium compound comprising the conjugated Ge4 chain, which was also characterized by the single crystal X-ray analysis. Bonding aspects in the latter compound have been additionally explored by DFT calculations, which revealed the occurrence of three σ bonds of different (covalent and dative) characters between the Ge atoms.

Three new sterically hindered acridin-4-ols have been prepared by alkylation of anilines with 3,5-di-tert-butyl-6-methoxymethylcatechol followed by oxidation of the reaction mixture. Formation of the acridine moiety was found to occur in the course of oxidation of the intermediate (anilinomethyl)catechol on contact with air in the Et2O/H2O–KOH system. The molecular structure of two acridin-4-ols was determined by single-crystal X-ray diffraction.

The electron density distribution based on a whole-molecule aspherical scattering factor (molecular invariom) and an asymmetric unit-cell aspherical scattering factor (crystal invariom) allows us to analyze both intramolecular and intermolecular interactions in a crystal with sufficient accuracy.

3a,6a-Diaza-1,4-diphosphapentalene (DDP) with indium triiodide forms the [In(DDP)I3] complex (I) with the ratio In : DDP = 1 : 1. The DDP ligand reacts with antimony(III) chloride to form a coordination polymer, the treatment of which with pyridine in the presence of pyridine hydrochloride affords the [PyH]+[Sb(DDP)Cl4)]– complex (II) (CIF files CCDC nos. 1937822 (I) and 1937823 (II)). The metal is coordinated to the phosphorus atom at an angle to the plane of the heteropentalene cycle (101.9(1)° and 106.0(1)° for In and Sb, respectively). This indicates that the coordination occurs due to electrons of the heteroaromatic π system.

The synthesis, crystal structure, thermal stability, porosity and magnetic properties of three new layered coordination polymers [(M2(pQ)3)·4DMAA]n (M3+ = La3+ (1), Pr3+ (2), Nd3+ (3); pQ2− – the dianionic form of 2,5-dihydroxy-3,6-di-tert-butyl-para-quinone; DMAA = N,N′-dimethylacetamide) are reported. The coordination polymers obtained were investigated by solid-state electrochemistry which demonstrates multistep one-electron transformations caused by the presence of redox-active dioxolene ligands.

A series of new isolable and thermally stable half-sandwich Ln(II) benzhydryl complexes coordinated by the sterically demanding ligands tert-butylcarbazol-9-yl [tBu4Carb]Ln[(p-tBu-C6H4)2CH](L) (Ln = Sm, L = DME (4); Ln = Yb, L = DME (5); Ln = Yb, L = TMEDA (6)) and 2,7-di-tert-butyl-fluoren-9-trimethylsilylyl [2,7-tBu2-9-Me3Si-C13H6]Yb[(p-tBu-C6H4)2CH](DME) (7) were synthesized by the alkane elimination reaction of [(p-tBu-C6H4)2CH]2Ln(Ln) (Ln = Sm, Yb) with tBu4CarbH and 2,7-tBu2-9-Me3Si-C13H7. X-ray analysis revealed that in 4, 5, and 7 the benzhydryl ligand is coordinated to the metal ion in an η3 coordination mode, while in 6 it is η1-bound. The type of coordination of the benzhydryl ligands in diamagnetic 5–7 is retained in their C6D6 solutions. Complexes 4–7 demonstrated unprecedented thermal stability and do not undergo decomposition after heating their solutions in C6D6 or toluene at 100 °C for 72 h. The reactions of [tBu4Carb]Ln[(p-tBu-C6H4)2CH](DME) (Ln = Sm (4), Ln = Yb (5)) with an excess of D...

The current study provides a clear understanding of the chemical properties of annelated 3a,6a-diaza-1,4-diphosphapentalenes (DDPs), which are best viewed as stabilized singlet phosphinidenes. It w...

The synthesis of electron-deficient gallium- and aluminum-centered species containing a redox-active dpp-Bian ligand (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) is described. The reaction of digallane [(dpp-Bian)Ga-Ga(dpp-Bian)] with [Ph3C][PF6] or AgPF6 resulted in polyoxidized species [(dpp-Bian)GaF2]2 (1), [(dpp-Bian)H2][PF6] (2), and [(dpp-Bian)GaF(O2PF2)]2 (3). The reaction of digallane with B(C6F5)3 led to electron-deficient gallylene [(dpp-Bian)GaB(C6F5)3] 4 of a dpp-Bian radical anion. The soft oxidation of digallane with tosyl cyanide gave the trinuclear cationic species [(dpp-Bian)Ga(Tos)3Ga(Tos)3Ga(dpp-Bian)][Ga(CN)4] (5) containing dpp-Bian radical anions. The reaction of [(dpp-Bian)AlEt2] with 1 equiv of [Ph3C][B(C6F5)4] resulted in the cationic complex [(dpp-Bian)AlEt2][B(C6F5)4] (6) of neutral dpp-Bian, while the treatment of [(dpp-Bian)AlEt(Et2O)] with 1 equiv of [Ph3C][B(C6F5)4] resulted in the compound [(dpp-Bian)AlEt(Et2O)][B(C6F5)4] (7) of a dpp-Bian radical anion. The reaction of diethylaluminum derivative [(dpp-Bian)AlEt2] with 1 equiv of B(C6F5)3 gave the cationic complex [{(dpp-Bian)AlEt}2F][EtB(C6F5)3] (8) containing radical-anion dpp-Bian ligands. The paramagnetic compounds 1, 2, 4, 5, 7, and 8 were characterized by electron paramagnetic resonance spectroscopy, and the diamagnetic complex 6 was characterized by NMR spectroscopy. The molecular structures of 1-6 and 8 were established by single-crystal X-ray diffraction analysis. Compounds 4 and 6-8 were found to be active initiators for immortal ring-opening polymerization of e-caprolactone.

The complexation of triphenylantimony(V) catecholates (3,6-DBCat)SbPh3 (1), (4,5-pip-3,6-DBCat)SbPh3 (2) and (4,5-Cl2-3,6-DBCat)SbPh3 (3) with neutral 4-(2,6-dimethylphenyliminomethyl)pyridine (Py-CH N–Ar) leads to the formation of hexacoordinated complexes (3,6-DBCat)SbPh3·(Py-CH N–Ar) (4), (4,5-pip-3,6-DBCat)SbPh3·(Py-CH N–Ar) (5) and (4,5-Cl2-3,6-DBCat)SbPh3·(Py-CH N–Ar) (6) (where 3,6-DBCat is 3,6-di-tert-butyl-catecholate, 4,5-pip-3,6-DBCat is 4,5-(N,N′-piperazine-1,4-diyl)-3,6-di-tert-butyl-catecholate, 4,5-Cl2-3,6-DBCat is 4,5-dichloro-3,6-di-tert-butyl-catecholate) containing NPyridine-coordinated neutral donor ligand Py-CH N–Ar. In the absence of donor ligands chlorine-containing catecholate 3 undergoes rearrangement in acetonitrile to form ionic complex [Ph4Sb]+[(4,5-Cl2-3,6-DBCat)2SbPh2]- (7). Complexes have been isolated and characterized by spectroscopic methods and cyclic voltammetry. The pyridine-containing catecholate (3,6-DBCat)SbPh3·Py (8) was also synthesized in order to compare it's the electrochemical behaviour with those of iminopyridine complexes 4–6. The presence of NPyridine-coordinated iminopyridine ligand changes the mechanism of catecholate oxidation in 4 and 6: the first oxidation wave (at Eox1p = 0.94 V for 4 and 0.99 V for 6) is two-electron and corresponds to the oxidation of dianionic catecholate ligand to a coordinated o-benzoquinone. In contrast to catecholates 4 and 6, the electrochemical behaviour of piperazine-containing catecholate 5 does not practically differ from that one for initial catecholate 2. The molecular structures of complexes 3–7 in crystals have been determined by single-crystal X-ray analysis.

Experimental and experimental-theoretical studies (the invariom approach, whole-molecule aspherical scattering factors) of the electron density distribution were carried out to compare its topological characteristics at the critical points (3, −1) of the NCN-(2-pyridinecarbonitrile)-(3,6-di-tert-butylcatecholato)triphenylantimony(v) complex. The topological characteristics of the electron density distribution at the critical points (3, −1) and the atomic volumes determined in experimental studies are almost in quantitative agreement with the results of experimental-theoretical investigation.

The complexes of La, Ce, Nd, Sm, Eu, Tb and Yb with benzoxazolyl-phenolate, benzothiazolyl-phenolate, benzoxazolyl-naphtholate, benzothiazolyl-naphtholate and 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione ligands were treated with n,γ-irradiation upon a sustained (45 h, absorbed dose of 120 krad, flux of neutrons 5·1013 n/cm2) and a pulse mode (3 ms, absorbed dose of 130 krad, flux of neutrons 3.6·1013 n/cm2). It was found that main characteristics of the compounds (shape of substance, color, IR absorption and photoluminescent spectra) have not changed. With an example of cerium complex [Ce(OON)3]2 it was revealed that the molecular structure of compounds after strong pulse irradiation also does not changed. However, computer simulations of neutron exposure on the same complexes showed significant shift of metal atoms and ligands. Possible reasons for the detected discrepancy between experimental and calculated data are discussed.

Three-nuclear clusters Nd2LnI5(S2)(S2N2)(THF)9 (Ln = Tb, Tm) were prepared by the disproportionation reaction of iodide-nitride [(NdI)3N2](THF)6 with LnI3(THF)3 in the presence of sulfur. Molecule of the cluster contains a flat inorganic core formed by two Nd and Ln atoms connected by dithiadiazine group. One of the Nd atoms is bound to the Ln3+ ion, besides terminal N atom of the bridge S2N2 fragment, by a bridge fragment S2. The second Nd atom is coordinated by two iodine anions and SN group forming unusual NdSN tree-member cycle. Structure of inorganic framework of the complexes is similar to that of earlier obtained monometallic analogues Ln3I5(S2)(S2N2)(THF)10 (Ln = Nd, Dy). In both new clusters the Ln atoms have the same coordination surrounding consisting of one iodine anion, S2 group and N atom of dithiadiazine ligand and occupy in the framework Nd2Ln(S2)(S2N2) the same position which corresponds to the lowest energy of the molecule. The nitride [(NdI)3N2](THF)6 in the presence of sulfur easy reacts as well with triiodides of La and Sm. Products isolated in these reactions do not form crystals suitable for X-ray study but the data of elemental analysis, fragment analysis, the found Nd: Ln ratio, spectroscopic and magnetic measurements allow to conclude that the structure of La, Sm products is similar to that of the above Tb, Tm analogs.

The electrochemical investigation of heteroligand o-semiquinonato-formazanato cobalt complexes [CoII(3,6-SQ)(Form)] (1) and [CoIII(3,6-SQ)2(Form)] (2) (where 3,6-SQ is 3,6-di-tert-butyl-o-benzosemiquinonate radical anion; Form is 1,3,5-triphenylformazanate anion) shows that the reduction of complexes proceeds through some successive stages corresponding to the transitions of radical anionic o-semiquinonato ligands to dianionic catecholates and the subsequent reduction of formazanate ligand with a formation of stable metallaverdazyl radical. In the accordance with CV data, we have accomplished the chemical reduction of heteroligand o-semiquinonato-formazanato cobalt complexes by treatment with one eqv. of Cp2Co. The resulting complexes [Co(3,6-Cat)(Form)]−[Cp2Co]+ (1a) and [Co(3,6-SQ)(3,6-Cat)(Form)]−[Cp2Co]+ (2a) have been isolated and characterized in details. The molecular structure of 1a in crystal state has been determined by single-crystal X-ray analysis. The magnetic susceptibility measurements, EPR spectroscopic and DFT studies have shown that complex [CoIII(3,6-SQ)(3,6-Cat)(Form)]−[Cp2Co]+ (2a) exists as a mixture of two valence tautomeric forms: more stable low-spin cobalt(III) isomer [CoIII(3,6-SQ)(3,6-Cat)(Form)]−[Cp2Co]+ and high-spin cobalt(II) isomer [CoII(3,6-SQ)2(Form)]−[Cp2Co]+.

Reaction of bis-o-semiquinonato nickel complex (2,2ʹ-dipyridine)Ni(dioxolene)2 (1) (dioxolene here – mono- or double-reduced forms of 3,6-di-tert-butyl-o-benzoquinone) or its cobalt analogue (2,2ʹ-dipyridine)Co(dioxolene)2) with (2,2ʹ-dipyridine)Sn(dioxolene)2 occur through ligands exchange and results in ate-complex [(2,2ʹ-dipyridine)2M(dioxolene)]+ [Sn(dioxolene)3]- (M = Ni (2), Co(3)). According to single crystal x-ray diffraction study both products are isostructural. Geometry of tin anion is intermediate between octahedral and trigonal prism. Analysis of bonds lengths in chelate cycles in tin anion one of dioxolene ligands is semiquinone anion-radical whereas the other two are catecholato-dianions. Geometry of inner coordination core of both cations is close to octahedral. Cobalt being in 3+ oxidation state is connected to catecholato-dianion. Nickel being in 2+ oxidation state is connected to semiquinonato anion-radical. Variable temperature magnetic susceptibility measurements of 2 indicate high spin nickel ferromagnetically coupled with semiquinonato anion-radical connected to it and independent semiquinone coordinated to tin. Cobalt cation is diamagnetic. EPR studies of ate-complex 3 in solution indicate two independent dynamic processes: solvation and migration of unpaired electron between three structurally identical ligands. Rate of this migration depends on solvent and temperature: from slow (CCl4, toluene) to fast (MeOH, CH3CN) in EPR time scale. Solvent role is solvation of the tin anion on one hand and the extent of isolation of ions: from “close pair” in CCl4 to “solvate separated pair” in methanol on the other hand. It is determined by solvent permittivity and dipole moment. Temperature dependence of hyperfine coupling constant with tin magnetic nuclei allowed estimating enthalpy and entropy of solvation. Temperature dependence of EPR spectrum shape together with it simulation allowed to evaluate the rates of spin migration and it activation parameters. In general, the regularities of ate-complex 2 behavior are the same but EPR lines are broader because of presence of high spin nickel and cation polarity effect is less than that in 3 because of smaller charge separation.

A new series of triphenylantimony(V) 3-alkylthio/arylthio-substituted 4,6-di-tert-butylcatecholates of the type (3-RS-4,6-DBCat)SbPh3, where R = n-butyl (1), n-hexyl (2), n-octyl (3), cyclopentyl (4), cyclohexyl (5), benzyl (6), phenyl (7), and naphthyl-2 (8), were synthesized from the corresponding catechol thioethers and Ph3SbBr2 in the presence of a base. The crystal structures of 1, 2, 3, and 5 were determined by single-crystal X-ray analysis. The coordination polyhedron of 1–3 is better described as a tetragonal pyramid with a different degree of distortion, while that for 5- was a distorted trigonal bipyramid (τ = 0.014, 0.177, 0.26, 0.56, respectively). Complexes demonstrated different crystal packing of molecules. The electrochemical oxidation of the complexes involved the catecholate group as well as the thioether linker. The introduction of a thioether fragment into the aromatic ring of catechol ligand led to a shift in the potential of the “catechol/o-semiquinone” redox transition to the anodic region, which indicated the electron-withdrawing nature of the RS group. The radical scavenging activity of the complexes was determined in the reaction with DPPH radical.

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 (

A tris-dioxolene manganese complex was synthesized and characterized (dioxolene- mono- and dianions of 3,6-DBQ-pipe, which is 3,6-di-tert-butyl-o-benzoquinone having a N,N’-piperazine bicycle as substituent in 4,5-positions). According to the bonds lengths distribution in the chelate cycles of the ligands the complex was identified as a bis-o-semiquinone-catecholato derivative of Mn(IV). Variable temperature magnetic susceptibility measurements indicate one unpaired electron per complex molecule as a result of strong intramolecular antiferromagnetic exchange interactions. The bis-o-semiquinone-catecholato manganese complex interacts with pyridine substituted by a nitronyl-nitroxide moiety forming a six-coordinate compound. The X-ray structural diffraction study of the complex executed at 100 K indicates a trans-arrangement of the pyridine ligands and the two catecholato dianionic chelates. Variable temperature magnetic susceptibility measurements of the complex with nitronyl-nitroxide give a magnetic moment of 5.5 µB which cannot be achieved in the spin system S = 3/2 (Mn4+) and 2 × S = 1/2 (two nitronyl-nitroxides). A valence tautomeric interconversion is proposed when the high multiplicity states [Mn3+(catecholate)(semiquinone)] and [Mn2+(semiquinone)2] are partly populated.

Novel bis-o-semiquinonato nickel complexes (2,2′-bpy)Ni(3,6-DBSQ)2 (1) and (1,10-phen)Ni(3,6-DBSQ)2 (2) was synthesized (2,2′-bpy - 2,2′-dipyridine; 1,10-phen - 1,10-phenanthroline; 3,6-DBSQ-anion-radical of 3,6-tert-butyl-o-benzoquinone). Single crystal X-ray diffraction study indicated distorted octahedral environment of nickel atom in both complexes. Variable temperature magnetic susceptibility measurement detected predomination of ferromagnetic exchange interactions between high spin nickel ion and anion-radicals of o-semiquinones. DFT calculations are in a good agreement with experimental structural and magnetic results.

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(SiMe3)2]3 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)3(DME)) and benzothiazolate (Ce(SSN)3(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. The lanthanum complex La(OSN)3(DME) has been synthesized similarly and structurally characterized. It was found that the solids of Ce(SSN)3(DME) and Ce(OSN)3(DME) exhibit a broad band photoluminescence peaking at 620 nm which disappears upon solvatation. With an example of OSN derivatives it was proposed that this behaviour is caused by the blue shift of the f–d transition of Ce3+ ions.

The reaction of 3a,6a-diaza-1,4-diphosphapentalene with 1-bromo-2-phenylacetylene has led to the formation of 1,1-bis(phenylethynyl)- and 1,4-dibromo-3a,6a-diaza-1,4-diphosphapentalene. The first has been also prepared via a different route by the reaction of 1,4-dichloro-3a,6a-diaza-1,4-diphosphapentalene with lithium phenylacetylenide in 96% yield. No isomeric 1,4-bis(phenylethynyl)-DDP has been formed in this reaction. The reaction in the 3a,6a-diaza-1,4-diphosphapentalene–[Ph3PC≡CPh]Br–carbazole three-component system proceeds as addition of carbazole to the initially formed complex of 3a,6a-diaza-1,4-diphosphapentalene with [Ph3PC≡CPh]Br with the rupture of the P–N bond. The products and intermediates of the reaction have been simulated by B3LYP/6-31+G(d) method.

The deprotonation of amidine 2-[Ph2P(O)]C6H4NHC(But)=N(2,6-Me2C6H3) (1) with BunLi affords lithium amidinate {2-[Ph2P(O)]C6H4NLiC(But)=N(2,6-Me2C6H3)}2 (2) having a dimeric structure, as demonstrated by X-ray diffraction. New amidinate dihalide complexes {2-[Ph2P(O)]C6H4NC(But)N(2,6-Me2C6H3)}NdHal2(THF)2 (Hal = I (3), Cl (4)) were synthesized by exchange reactions of lithium and potassium amidinates with anhydrous neodymium halides NdHal3(THF)n (Hal = I, n = 3.5; Cl, n = 0). The X-ray diffraction studies showed that the new compounds are monomeric and the amidinate ligand is tridentate. Chloride complex 4 involved in the three- and four-component catalyst systems 4–AlR3–[Ph3C] [B(C6F5)4] (1: 10: 1; AlR3 = AlBui 3, AlMe3), 4–AlR3–PriOH (1: 10: 10; AlR3 = AlBui3, AlMe3), and 4–AlR3–[Ph3C][B(C6F5)4]–PriOH (1: 10: 1: 10; AlR3 = AlBui3, AlMe3) exhibits activity in stereospecific isoprene polymerization and allows the preparation of high-molecular-weight polyisoprene samples with exceptionally high cis-1,4-unit content (up to 99.4%).

A series of homo and heterometallic La, Li and Na complexes with 2-(2-benzoxyazol-2-yl)phenolate (L) ligands were synthesized using La[N(SiMe3)2]3 and M[N(SiMe3)2] (M = Li, Na) or La(Cp)3 as starting materials for La2(L)6 (1), La2(L)6(bipy) (2), La(L)2Cp(DME) (3), La2Li(L)7 (4), Li(L) (5), Na(L) (6). Photoluminescent (PL) properties of these compounds, staring phenol H(L) as well as previously obtained complex LaNa(L)4(DME)2 (7) were studied at 300 and 77 K. Molecular structure of 2, 3 and 4 were determined by X-ray analysis. All the compounds in THF solution at 300 K upon UV excitation (370 nm) revealed a bright fluorescence in the range 430–460 nm and moderate phosphorescence as a shoulder at about 500 nm. The total quantum yield (QY) is 1–35%. At 77 K all lanthanum compounds (except 3) in THF solution exhibit weak or moderate fluorescence but intense phosphorescence (τ 3.5 – 95.8 ms). The PL spectra of solid samples at 300 K strongly differ from those of solutions, apparently due to the effects of crystal packing, the shape and size of the crystals. The emission of H(L) is most intensive but the PL of 1 has lowest efficiency. It is assumed that phosphorescence occurs from excimers and exciplexes, the formation of which in the compounds studied has been confirmed by X-ray diffraction analysis.

In the search for a way to organic up-converter materials the complex [(OON)2Er(THF)](μ-O)[(OON)2Yb(THF)] with the (benzoxazol-2-yl)phenolate (OON) ligand was synthesized. Upon excitation by laser with λex 405 nm light the complex displayed only emission of the Yb3+ ion indicating the lack of energy transfer from Yb to Er. To develop a method for preparation of other up-converter materials the complexes [Yb4(SON)8(μ4-O)(OH)2 and [Eu4(OON)10Li2(3-O)2] with (benzothiazol-2-yl)phenolate (SON) and (benzoxazol-2-yl)phenolate ligands were synthesized using water as a co-reagent. The X-ray study revealed that the clusters contain μ2-O, μ3-O and μ4-O bridges and short Ln…Ln contacts. These modelling syntheses showed that the method is applicable for preparation of potential up-convertion materials with Ln-O-Ln’ groupings.

In the present research, the temperature dependence of heat capacity of tris(pentafluorophenyl)-4-pyridylethylgermane (C6F5)3Ge–CH2–CH2–C5H4N was studied by precise adiabatic vacuum calorimetry and differential scanning calorimetry over the temperature range from 6 to 450 K. The temperature and enthalpy of fusion of tris(pentafluorophenyl)-4-pyridylethylgermane and the total mole fraction of impurities have been determined. The thermal stability of the sample was investigated by thermogravimetric analysis. The experimental data were used to calculate the standard thermodynamic functions: heat capacity, enthalpy, entropy, and the Gibbs energy over the range from T → 0 to 420 K for crystalline and liquid states. For the compound under study, the standard entropy of formation in the crystalline state was calculated at T = 298.15 K. In addition, the structure of the investigated compound was established, and corresponding structural parameters were determined.

The electron density distribution in Ph3Sb(O2CC(Me)=CH2)2 ⋅ C6H6 and structural and energy aspects of the phase transition in the crystals of this compound were investigated using a series of common (Ib−Ie) and high-precision (Ia) X-ray diffraction experiments. A considerable difference between the root-mean-square atomic displacements in two chemically equivalent methyl groups of the methacrylate ligands was revealed. This difference was shown to be caused by considerable energy difference of the intra- and intermolecular contacts of the corresponding methyl groups.

A number of mononuclear triphenylantimony(V) 3,5-di-tert-butylcatecholates of the type (6-AlkOCH2-3,5-DBCat)SbPh3 functionalized with alkoxymethyl group in the 6th position of aromatic ring in catecholato ligand, where Alk = Me (1), Et (2), iPr (3), tBu (4), n-Hexyl (5), and binuclear bis-catecholate Ph3Sb(3,5-DBCat-CH2OCH2-3,5-DBCat)SbPh3 (6) have been synthesized and characterized in details. The molecular structures of 1·0.5 (n-hexane), 2, 3, 4, 5·2MeOH, 6·2 (n-hexane) and 6·acetone have been determined by means of single-crystal X-ray analysis. The presence of alkoxymethyl-group in catecholate ligand does not lead to its coordination to the central antimony atom. Complexes 1–4 and 6 possess pentacoordinated environment of the central antimony atoms varying from the trigonal bipyramidal to the distorted tetragonal pyramidal. In crystal, molecules of complexes 1–5 form pairs where the “CPh–H … π-system” interactions were found. The coordination environment of the central antimony atom in 5∙2MeOH is a distorted octahedral with coordinated methanol; the second methanol molecule is fixed between thehydroxyl group of coordinated methanol and the oxygen atom of hexyloxymethyl-group in the 6th position of catecholate ligand through the intramolecular hydrogen bonding. The electrochemical oxidations of complexes 1–4 proceed as two one-electron oxidations (the quasireversible oxidation “catecholate/o-semiquinolate” and the irreversible oxidation “o-semiquinolate/o-benzoquinone”). The first half-wave potential (E11/2) depends weakly on the alkyloxy substituent in AlkO-CH2 group due to a weak inductive effect of AlkO group to the catecholate aromatic ring through the methylene linker. For binuclear bis-catecholate 6, the first redox stage is two-electronic quasi-reversible peak without the separation of two stages into two one-electron processes, which indicates the absence of the electronic interaction between the two catecholate fragments.

The new pentacoordinated chloro-bis-o-iminosemiquinonato complexes (imSQOMe)2MnIIICl (1) and (imSQOMe)2FeIIICl (2) based on 4,6-di-tert-butyl-N-(2-methoxyphenyl)-o-aminophenol were synthesized. As established by X-ray diffraction analysis the compounds 1 and 2 are structural analogues. No additional coordination of methoxy groups to metal center was found in the case of both investigated complexes. Electrochemical oxidation leads to the bonding of functional –OMe group with iron(III) ion in compound 2. Triplet ground spin state (S = 1) for 1 is realized due to a prevailing strong antiferromagnetic interaction between unpaired electrons of high-spin manganese(III) (d4, SMn = 2) and two o-iminosemiquinonato radicals (SR = 1/2). The temperature dependence of effective magnetic moment (μeff) indicates the doublet ground spin state (S = 1/2) and thermally occupied quartet spin state (S = 3/2) for complex 2. The performed DFT calculations demonstrate that the magnetic properties of 2 are conditioned by the strong antiferromagnetic exchange of Fe-imSQ type as well as the transformation of iron(III) ion from high-spin configuration to intermediate-spin state (SFe = 5/2 → S = 3/2) with a decrease in temperature as a result of spin-crossover. The latter phenomenon was proved by Mossbauer spectroscopy. At the same time the intermediate-spin manganese(III) isomer (i.s.MnIII, SMn = 1) is destabilized by more than 20 kcal/mol, and therefore spin-crossover in compound 1 is impossible.

Mononuclear terbium and erbium complexes of the composition Ln(mbtF)3phen and the dinuclear complex Tb2(mbtF)4(OH)2(phen)2 (mbtF is 4,5,6,7-tetrafluoro-2-mercaptobenzothiazolate, phen is 1,10-phenanthroline) were synthesized. The structures of the complexes Er(mbtF)3phen and Tb2(mbtF)4(OH)2(phen)2 were determined by X-ray diffraction. In the solid state, the terbium and erbium complexes exhibit intense metal-centered photoluminescence. Based on the complexes Ln(mbtF)3phen, double-layer organic light-emitting diodes (OLEDs) were assembled. These OLEDs exhibit electroplex emission with a band maximum at 630 nm.

A number of 3,6-di-tert-butyl-catecholates of trialkyl- and triarylantimony(V) (3,6-DBCat)SbR3, where R is methyl (Me), n-hexyl (Hex), cyclohexyl (Cyclohex), o-tolyl (o-Tol), p-tolyl (p-Tol), p-biphenyl (p-biPh), p-fluorophenyl (p-FPh), p-chlorophenyl (p-ClPh) have been synthesized and characterized in details. The molecular structures of (3,6-DBCat)SbMe3, (3,6-DBCat)Sb(p-Tol)3 and (3,6-DBCat)Sb(p-ClPh)3·acetone were determined by single-crystal X-ray analysis. The electrochemical properties of complexes were investigated by means of cyclic voltammetry. It was shown that the electron-acceptor substituents at the central antimony atom shift the oxidation potentials of the corresponding catecholate complexes to the anodic region while electron-donor groups make the oxidation of catecholate complexes to o-semiquinolate derivatives easier.

A series of alkali-metal alkyl complexes containing a tridentate benzhydryl ligand, [2,2′-(4-MeC6H4NMe2)2CH]Li(TMEDA) (1TMEDA), [2,2′-(4-MeC6H4NMe2)2CH]Na(THF)3 (2THF), {[2,2′-(4-MeC6H4NMe2)2CH]K(THF}2 (3THF), and [2,2′-(4-MeC6H4NMe2)2C(SiMe3)]K (5), were synthesized and structurally characterized. Smaller Li and Na ions form the monomeric complexes 1TMEDA and 2THF featuring η4-CCCN coordination of the [2,2′-(4-MeC6H4NMe2)2CH]− ligand, while the larger K affords the dimeric complex 3THF, in which two different types of metal–ligand bonding, μ-η5-pentadienyl-κ2-NN and μ-κ3-CNN:η6-arene are realized. Application of the Me3Si-substituited analogue [2,2′-(4-MeC6H4NMe2)2C(SiMe3)]− leads to the formation of the 1D coordination polymer {[2,2′-(4-MeC6H4NMe2)2C(SiMe3)]K}∞ (5) with μ-η3:η6 bridging coordination of the ligands to potassium ions.

New bis(amidinate) complexes of calcium, [2,6-Pri2C6H3NC(But)NC6H4OMe-2]2Ca(DME) (2), and divalent ytterbium, [2,6-Pri2C6H3NC(But)NC6H4OMe-2]2Yb (4), were synthesized by the transamination of the bis(amide) derivatives [(Me3Si)2N]2M(THF)2 (M = Ca, Yb) with two equivalents of amidine 2,6-Pri2C6H3N=C(But)N(H)C6H4OMe-2, in which one nitrogen atom bears an o-methoxyphenylene moiety capable of coordinating a metalion. An X-ray diffraction study showed that, despite very similar ionic radii of Ca2+ and Yb2+, the amidinate ligands in complexes 2 and 4 bind to these ions in different coordination modes. In the calcium complex, both ligands adopt a κ2-N, O-chelating coordination mode. In the divalent ytterbium compound, one ligand is chelating and binds to the metalion in a κ2-N, O-coordination mode, while the second ligand is coordinated via both the N and O (κ2) atoms and the arene ring of the 2,6-Pri2C6H3 moiety (η6-coordination mode).

A reaction of dimethyl bicyclo[2.2.2]oct-5-ene-endo-2,endo-3-dicarboxylate with 1,3-benzо- thiazole-2- and 3-methoxycarbonylpyridine-2-sulfenyl chlorides leads to two types of heterocyclization products, which are formed through the ring closure by the oxygen atom of the carbоmethoxy group and/or by the nitrogen atom of the hetaryl fragment of the sulfenylating agent. The product ratio is affected by the medium nature and structural features of sulfenyl chlorides.

An approach based on the simultaneous use of a source function and a noncovalent interaction index for studying interatomic interactions in the absence of bond critical points is offered. This approach comprises the selection of reference points for the source function on the noncovalent interaction index isosurface.

Oxidation of 1,1′-methylenebis[4-tert-butyl-2-(diphenylphosphino) benzene] by H2O2 or S8 in toluene affords two new PCP-type pincer ligands. The methylene group deprotonation in the new ligands as well as in their precursor by n-BuLi or LiCH2SiMe3 failed, while the methylene group in the precursor 1,1′-methylenebis[4-tert-butyl-2-(diphenylphosphino)benzene] was readily metallated by Lochmann–Schlosser superbase to form the unstable potassium complex which in turn was readily transformed into new {5-But-2-[4-But-2-(Ph2P)C6H3(Ph)CH]C6H3P(Ph)K(OEt2)}2 complex due to phenyl group migration.

A series of amido Ca and Yb(II) complexes LM[N(SiMe3)2](THF) (1Yb, 1-4Ca) coordinated by amidine-amidopyridinate ligands L1-4 were synthesized via a transamination reaction between proligands L1-4H and bisamido complexes M[N(SiMe3)2]2(THF)2 (M = Yb, Ca). The reactions of Yb[N(SiMe3)2]2(THF)2 with proligands L2H-L4H containing CF3 and C6H4F fragments do not allow for preparing the target Yb(II) complexes, while the Ca analogues were synthesized in good yields. Complexes 1Yb and 1-4Ca were evaluated as precatalysts for hydrophosphination of styrene, p-substituted styrenes, α-Me-styrene, and 2,3-dimethylbutadiene with various primary and secondary phosphines (PhPH2, 2,4,6-Me3C6H2PH2, 2-C5NH4PH2, Ph2PH, Cy2PH). Complexes 1Yb, 1-4Ca performed high catalytic activities in styrene hydrophosphination with PhPH2 and Ph2PH and demonstrated high regioselectivity affording exclusively the anti-Markovnikov addition products. For primary PhPH2 the reactions (1:1 molar ratio of substrates) catalyzed by 1Yb, 1Ca, and 2Ca proved to be highly chemoselective affording the secondary phosphine Ph(PhCH2CH2)PH; however, complexes 3Ca and 4Ca led to the formation of both secondary and tertiary phosphines in 80:20 and 86:14 ratios. Styrene hydrophosphinations with 2,4,6-Me3C6H2PH2 and 2-pyridylphosphine for all complexes 1Yb and 1-4Ca proceeded much more slowly compared to PhPH2. Addition of 2-C5NH4PH2 to styrene catalyzed by complex 1Yb turned out to be non-regioselective and led to the formation of a mixture of Markovnikov and anti-Markovnikov addition products, while all Ca complexes enabled regioselective anti-Markovnikov addition. Complexes 1Ca and 1Yb containing catalytic centers featuring similar ionic radii performed different catalytic activity: the ytterbium analogue proved to be a more active catalyst for intermolecular hydrophosphination of styrene with Cy2PH, 2-C5NH4PH2, and PhPH2, but less active with sterically demanding 2,4,6-Me3C6H2PH2. Styrenes containing in p-position electron-donating groups (Me, tBu, OMe) performed with noticeably lower rates in the reactions with PhPH2 compared to styrene. Complexes 1Yb, 1Ca, 2Ca, 3Ca, and 4Ca enabled addition of PhPH2 toward the double C═C bond of α-Me-styrene, and the reaction rate for this substrate is noticeably lower; however quantitative conversions were reached in ∼40 h. Complexes 1Ca and 2Ca promoted 1,2-addition of PhPH2 to 2,3-dimethyl butadiene with excellent regio- and chemoselectivity to afford linear secondary phosphines. Hydrophosphination of inert 1-nonene with Ph2PH with 40% conversion becomes possible due to the application of complex 2Ca (40 h, 70 °C). The rate law for the hydrophosphination of styrene with Ph2PH catalyzed by 1Ca was found to agree with the idealized equation: v = k[styrene]1[1Ca]1.

Heptacoordinated tin complexes with pentadentate redox-active ligands containing the diiminopyridine fragment combined with two sterically hindered phenolate coordination centers, LSn-Cl2 and L'SnCl2 (L and L' are dianions of deprotonated 2,6-bis[2,4-di-tert-butyl-6-(methylidenylamino) phenol]pyridine and 2,6-bis[2,4-di-tert-butyl-6-(ethylidenylamino)phenol]pyridine, respectively), are synthesized. The molecular and electronic structures of the synthesized compounds were studied by X-ray diffraction analysis (for complex I, CIF file CCDC no. 1557838), a set of spectral methods, and quantum-chemical calculations. The redox properties of the obtained complexes are characterized by cyclic voltammetry.

The oxidative addition of bis-o-benzoquinone Q–(CH=N–N=CH)–Q (L), in which two 3,5-ditert-butyl-o-benzoquinones are linked to each other in positions 6 via the CH=N–N=CH group, to triphenylstibine gave a new binuclear triphenylantimony(V) bis-catecholate complex, Ph3Sb(Cat–(CH=N–N=CH)–Cat)SbPh3 (I). Recrystallization of I from a methanol–trichloromethane mixture resulted in an additional coordination of a methanol molecule to each antimony atom to give the binuclear complex, (CH3OH)Ph3Sb(Cat–(CH=N–N=CH)–Cat)SbPh3(CH3OH) (I · 2CH3OH), the crystals of which (I · 2CH3OH) · 2CH3OH · CHCl3 (II) contain additionally two methanol solvate molecules, which fix the geometry of the nitrogen-containing bridging group, and a trichloromethane molecule. The molecular structure of compound II in the crystalline state was determined by X-ray diffraction (CIF file CCDC no. 1560840).

Lithium silylamides 1,8-C10H6[N(SiMe3)Li(L)]2 (L = Et2O (); L = TMEDA (1TMEDA)), when treated with PhC[triple bond, length as m-dash]N, formed the adducts 1,8-C10H6[N(SiMe3)Li(N[triple bond, length as m-dash]CPh)(OEt2)][N(SiMe3)Li(OEt2)] () and 1,8-C10H6[N(SiMe3)Li(N[triple bond, length as m-dash]CPh)][N(SiMe3)Li(TMEDA)] (2TMEDA) containing one benzonitrile molecule coordinated to Li ion while the second molecule retains a coordinated L ligand. The salt metathesis reactions of LnCl3 (Ln = Y, Sm) with equimolar amounts of and 2TMEDA (THF, 4 h, 40 °C) resulted in benzonitrile insertion and formation of new dianionic amido-amidinate ligands. The reactions of with LnCl3 afforded ionic chloro complexes [{1,8-C10H6[NSiMe3][NC(Ph)NSiMe3]}{1,8-C10H6[N(H)SiMe3][NC(Ph)NSiMe3]}LnCl][Li(L)n] (Ln = Y, L = THF, n = 4 (3Y), Ln = Sm, L = DME, n = 3 (3Sm)), while the reaction of 2TMEDA and YCl3 leds to the formation of the neutral salt-free yttrium chloro complex {1,8-C10H6[NSiMe3][NC(Ph)NSiMe3]}YCl(TMEDA) (4). The treatment of 3Y and 4 with tBuOK enabled the synthesis of tert-butoxides [{1,8-C10H6[NSiMe3][NC(Ph)NSiMe3]}{1,8-C10H6[N(H)SiMe3][NC(Ph)NSiMe3]}YOtBu][Li(THF)4] (7) and {1,8-C10H6[NSiMe3][NC(Ph)NSiMe3]}YOtBu(TMEDA) (8). Complexes 7 and 8 were evaluated as initiators for the ring opening polymerization of rac-lactide. Neutral tert-butoxide complex 8 demonstrated significantly higher activity compared to that of ionic 7.

In an attempt to get more insight into the way of formation of recently obtained unusual iodide-sulfide-nitride clusters Ln 3 I 5 (S 2 )(S 2 N 2 )(THF) 10 (Ln = Nd ( 1 ), Dy ( 2 )) and modify this synthesis reactions of dysprosium iodide-nitride with sulfur were carried out in various conditions. It was found that the reaction of as prepared dysprosium iodide-nitride [(DyI 2 ) 3 N] x with sulfur in THF yields ionic complex {[DyI 2 (THF) 5 ] + [DyI 2 S 5 (THF) 2 ] − } ( 3 ) anionic part of which contains six-membered cycle DyS 5 . The same reaction in iso -propylamine medium affords ionic iodide-sulfide{[( i PrNH 2 ) 4 Dy(μ- η 2 :η 2 - S 2 )] 2 } 2+ [I − ] 2 ( 4 ) containing bipyramide core formed by two apical Dy 3+ cations and two equatorial S 2 fragments. The nitride [(DyI) 3 N 2 ] in THF does not interact with sulfur but upon addition of triiodide DyI 3 the reaction affords cluster 2 in moderate yield.

A series of amido Ca complexes LCa[N(SiMe3)2](THF) (1-4) coordinated by Schiff base ligands L1-4 were synthesized via an amine elimination reaction between proligands L1-4H and a bisamido complex Ca[N(SiMe3)2]2(THF)2 in good yield. Unlike Ca[N(SiMe3)2]2(THF)2, the reactions of M[N(SiMe3)2]2(THF)2 (M = Yb, Sm) with proligands L1-4H do not lead to the formation of the target Ln(ii) amido complexes. The reaction of Yb[N(SiMe3)2]2(THF)2 with L1H is accompanied by intramolecular C-H bond activation of a quinoline ring and results in the formation of complex 6 coordinated by a new trianionic [NNNNOO] ligand. The reactions of amido complexes 1 and 4 with PhSiH3 do not allow for preparing the related hydrides but afford homoleptic bis(phenolate) complexes 5 and 7 due to a ligand redistribution reaction. Amido complexes 1-4 were evaluated as precatalysts for cross-dehydrogenative coupling of silanes (PhSiH3, Ph(Me)SiH2, and Ph3SiH) and aliphatic, aromatic and cyclic amines (RNH2 and R2NH).