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Synthesis and structural characterization of a family of germanium-dioxolene complexes with ditopic N-donor ligands (L 1 -L 5 ) (L 1 =1,2-bis(pyridin-2-ylmethylene)hydrazine L 2 =1,6-bis-(pyridin-2-yl)-2,5-diaza-1,5-hexadiene, L 3 =N,N-bis(pyridin-2-ylmethylene)-1,4-benzenediamine, L 4 =N,N-bis(pyridin-2-ylmethylene)-(biphenyl)-4,4-diamine, L 5 =2,2'-azopyridine) is reported. The reaction of germanium bis-catecholate with bridging ligands L 1 - L 4 , differing by the nature of the linker between pyridine sites gives rise to dinuclear digermanium complexes (36Cat 2 Ge) 2 L 1-4 (36Cat=dianion of 3,6-di-tert-butylcatechol) 1-4 of DMAMD type (donor-metal-acceptor-metal-donor) with a charge transfer in the UV-Vis region. In opposite, the interaction of the 36Cat 2 Ge with 2,2'-azopyridine (L 5 ) results in the two-electron transfer from the donor 36Cat 2- ligands to the azopyridine bridge forming stable open-shell complex 5 [(36SQ)(36CatGe)] 2 (L 5 ) 2- (36SQ=radical-anionic semiquinonate ligand). Molecular structures of compounds 3 and 5 were determined by single crystal X-ray diffraction analysis. Electronic structures of complexes 1-5 were studied by means of DFT calculations., (© 2024 Wiley-VCH GmbH.)

The reaction of dialane [LAl-AlL] (1; L=dianion of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene, dpp-bian) with carbon dioxide results in two different products depending on solvent. In toluene at temperatures of about 0 °C, the reaction gives cycloadduct [L(CO 2 )Al-Al(O 2 C)L] (2), whereas in diethyl ether, the reaction affords oxo-bridged carbamato derivative [L(CO 2 )(Et 2 O)Al(μ-O)AlL] (3). The DFT and QTAIM calculations provide reasonable explanations for the reversible formation of complex 2 in the course of two subsequent (2+4) cycloaddition reactions. Consecutive transition states with low activation barriers were revealed. Also, the DFT study demonstrated a crucial effect of diethyl ether coordination to aluminium on the reaction of dialane 1 with CO 2 . The optimized structures of key intermediates were obtained for the reactions in the presence of Et 2 O; calculated thermodynamic parameters unambiguously testify the irreversible formation of the product 3., (© 2021 Wiley-VCH GmbH.)

We report here the synthesis, structure, magnetic and photoluminescent properties of three new bifunctional Schiff-base complexes [Dy(L 1 ) 2 (py) 2 ][B(Ph) 4 ]⋅py (1), [Dy(L 1 ) 2 Cl(DME)] ⋅ 0.5DME (2) and [Dy(L 2 ) 2 Cl] ⋅ 2.5(C 7 H 8 ) (3) (HL 1 =Phenol, 2,4-bis(1,1-dimethylethyl)-6-[[(2-methoxy-5-methylphenyl)imino]methyl]; HL 2 =Phenol, 2,4-bis(1,1-dimethylethyl)-6-[[(2-methoxyphenyl)imino]methyl]). The coordination environment of the Dy 3+ ion and the direction of the anisotropic axis may be controlled by the combination of the substituent groups of the Schiff bases, the nature of the counter-ions (Cl - vs. BPh 4 - ) and the coordinative solvent molecules. A zero-field slow relaxation of the magnetization is evidenced for all complexes but strong differences in the relaxation dynamics are observed depending on the Dy 3+ site geometry. In this sense, complex 1 exhibits an anisotropy barrier of 472 cm -1 , which may be favourably compared to other related examples due to the shortening of the Dy-O bond in the axial direction. Besides, the three complexes exhibit a ligand-based luminescence making them as bifunctional magneto-luminescent systems., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The first example of intermolecular hydrophosphination of styrene, 2-vinylpyridine and phenylacetylene with PH 3 catalyzed by bis-(amido) complexes [(Me 3 Si) 2 N] 2 M(NHC) 2 (M=Ca, Yb, Sm) coordinated by NHC ligands is described. The reactions of styrene with PH 3 proceed under mild conditions in quantitative yields to afford only anti-Markovnikov product and allow for the chemoselective synthesis of primary, secondary and tertiary phosphines. Addition of phenylacetylene to PH 3 regardless the initial molar substrates ratio results in the exclusive formation of a tertiary tris-(Z-styryl)-phosphine. Crucial effect of the Lewis base coordinated to the metal ion in precatalyst on catalytic activity in styrene hydrophosphination with PH 3 was demonstrated. Free NHCs were also found to be able to promote addition of PH 3 to styrene, however they provide much lower reaction rates compared to the metal complexes., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The synthesis, and magnetic and photoluminescence investigations of two bifunctional dysprosium complexes based on tridentate Schiff base ligands is reported. Magnetic investigations reveal a genuine single-molecule magnet (SMM) behavior, with out-of-phase signals up to 60 K, and tunable emission arising from the Schiff base ligands., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The half-sandwich tetra-tert-butylcarbazol-9-yl iodo complex [(tBu 4 Carb)Sm(μ-I)(THF) 2 ] 2 (1) was synthesized by the salt metathesis reaction of tBu 4 CarbK and SmI 2 (THF) 2 in THF. Complex 1 along with metallic Cu was also isolated from the oxidation reaction of (tBu 4 Carb) 2 Sm by CuI. The formation of stable radical tBu 4 Carb . was detected in this non-conventional process, indicating preferential oxidation of anion tBu 4 Carb - vs. Sm II . The treatment of 1 with two equivalents of dibenzo-18-crown-6 resulted in heterolytic dissociation of a η 5 -bond Sm-tBu 4 Carb and afforded an ionic compound [tBu 4 carb - ][SmI(crown)(THF) 2 ] + (4). Alkylation of 1 with o-NMe 2 C 6 H 4 CH 2 K (1:2 molar ratio) in THF allowed for the synthesis of half-sandwich Sm II alkyl complex (tBu 4 Carb)SmCH 2 (o-NMe 2 C 6 H 4 CH 2 )(THF) 2 (5) in 55 % yield. The amido complex (tBu 4 Carb)SmN(SiMe 3 ) 2 (DME) (6) was obtained by the reaction of 1 with two molar equivalents of NaN(SiMe 3 ) 2 in THF in 89 % yield., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Neutral Y(III) dialkyl complexes supported by tridentate N(-) ,N,N monoanionic methylthiazole- or benzothiazole-amidopyridinate ligands have been prepared and completely characterized. Studies on their stability in solution revealed progressive rearrangement of the coordination sphere in the benzothiazole-containing system through an unprecedented metal-to-ligand alkyl migration and subsequent thiazole ring opening. Attempts to synthesize hydrido species from the dialkyl precursor led to the generation of a dimeric yttrium species stabilized by a trianionic N(-) ,N,N(-) ,S(-) ligand as the result of metal-to-ligand hydride migration with chemoselective thiazole ring opening and subsequent dimerization through intermolecular addition of the residual YH group to the imino fragment of a second equivalent of the ring-opened intermediate. DFT calculations were used to elucidate the thermodynamics and kinetics of the process, in support of the experimental evidence. Finally, all isolated yttrium complexes, especially their cationic forms prepared by activation with the Lewis acid Ph3 C(+) [B(C6 F5 )4 ](-) , were found to be good candidate catalysts for intramolecular hydroamination/cyclization reactions. Their catalytic performance with a number of primary and secondary amino alkenes was assessed., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Acetylene, phenylacetylene, and alkylbutynoates add reversibly to (dpp-bian)Ga-Ga(dpp-bian) (dpp-bian=1,2-bis[(2,6-diisopropylphenyl)-imino]acenaphthene) to give addition products [dpp-bian(R(1)C=CR(2))]Ga-Ga[(R(2)C=CR(1))dpp-bian]. The alkyne adds across the Ga-N-C section, which results in new carbon-carbon and carbon-gallium bonds. The adducts were characterized by electron absorption, IR, and (1)H NMR spectroscopy and their molecular structures have been determined by single-crystal X-ray analysis. According to the X-ray data, a change in the coordination number of gallium from three [in (dpp-bian)Ga-Ga(dpp-bian)] to four (in the adducts) results in elongation of the metal-metal bond by approximately 0.13 Å. The adducts undergo a facile alkynes elimination at elevated temperatures. The equilibrium between [dpp-bian(PhC=CH)]Ga-Ga[(HC=CPh)dpp-bian] and [(dpp-bian)Ga-Ga(dpp-bian) + 2 PhC≡CH] in toluene solution was studied by (1)H NMR spectroscopy. The equilibrium constants at various temperatures (298≤T≤323 K) were determined, from which the thermodynamic parameters for the phenylacetylene elimination were calculated (ΔG°=2.4 kJ mol(-1), ΔH°=46.0 kJ mol(-1), ΔS°=146.0 J K(-1) mol(-1)). The reactivity of (dpp-bian)Ga-Ga(dpp-bian) towards alkynes permits use as a catalyst for carbon-nitrogen and carbon-carbon bond-forming reactions. The bisgallium complex was found to be a highly effective catalyst for the hydroamination of phenylacetylene with anilines. For instance, with [(dpp-bian)Ga-Ga(dpp-bian)] (2 mol%) in benzene more than 99% conversion of PhNH(2) and PhC≡CH into PhN=C(Ph)CH(3) was achieved in 16 h at 90 °C. Under similar conditions, the reaction of 1-aminoanthracene with PhC≡CH catalyzed by (dpp-bian)Ga-Ga(dpp-bian) formed a carbon-carbon bond to afford 1-amino-2-(1-phenylvinyl)anthracene in 99% yield., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A series of new bis(guanidinate) alkoxide Group 3 metal complexes [Ln((Me3Si)2NC(NiPr)2)2(OR)] (R=OtBu, Ln=Y, Nd, Sm, Lu; R=OiPr, Ln=Y, Nd, Lu) has been synthesized. X-ray structural determinations revealed that bis(guanidinate) tert-butoxides are monomeric complexes. The isopropoxide complex [Y((Me3Si)2NC(NiPr)2)2(OiPr)] undergoes slow decomposition in solution, to afford the unusual dimeric amido complex [(Y((Me3Si)2NC(NiPr)2)2(mu-N(iPr)C triple chemical bond N))2]. Complexes [Ln((Me3Si)2NC(NiPr)2)2(OR)] (R=OtBu, Ln=Y, Nd, Sm, Lu; R=OiPr, Ln=Y, Nd, Lu) are active catalysts/initiators for the ROP of rac-lactide and rac-beta-butyrolactone under mild conditions. Most of those polymerizations proceed with a significant degree of control. Bis(guanidinate) alkoxides appear to be well suited for achieving immortal polymerization of lactide, through the introduction of large amounts of isopropanol as a chain-transfer agent. The synthesized complexes are able to promote the stereoselective ROP of rac-beta-butyrolactone to afford syndiotactic poly(hydrobutyrate) through a chain-end control mechanism, while they are surprisingly non-stereoselective for the ROP of lactide under strictly similar conditions.