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Six new coordination polymers (CPs) of cadmium based on an extended anilate-type ligand, 4,4′-(1,4-phenylenebis(azanylylidene))bis(3,6-di-tert-butyl-2-hydroxycyclohexa-2,5-dienone) (H2L), have been synthesized. The series of coordination polymers includes [Cd(L)(DMF)] (1), 1D-CP [Cd(L)(dipy-1)]·2DMF (2A) and 2D-CP [Cd(L)(dipy-1)]·DMF (2B), [Cd2(L)2(dipy-2)(DMF)2] (3), [Cd(HL)(CH3COO)(dabco)] (4) and [Cd(L)(ur)2]·(H2L) (5) (where L – deprotonated form of H2L, DMF – N,N′-dimethylformamide, dipy-1 – 4,4′-trimethylenedipyridine, dipy-2 – 4,4′-dipyridyl, dabco – 1,4-diazabicyclo[2.2.2]octane, ur – urotropine). The crystal structure and thermal decomposition of 1D- and 2D-coordination polymers are reported. The structural diversity of the synthesized compounds was found to depend on the additional neutral donor ligands in the cadmium coordination sphere. Thus, the introduction of the flexible N-donor ligand dipy-1 into the cadmium coordination sphere leads to the formation of two types of coordination polymers (1D and 2D). The use of the rigid ligand dipy-2 promotes the formation of "honeycomb" 2D-CPs. The use of shorter N-donor ligands dabco and ur leads to linear derivatives in which the ligands being coordinated by cadmium don't act as "crosslinkers" of the chains in the network. [ABSTRACT FROM AUTHOR]

We report the synthesis, structures, and magnetic and luminescence properties of a series of new monoand dinuclear Er3+ complexes derived from sterically demanding aryloxide and fluorinated alkoxide ligands: [4-tBu-2,6-(Ph2CH)2C6H2O]3Er(THF) (1), [(C6F5)3CO]3Er(Me3SiOH) (2), [(C6F5)3CO]3Er[(Me3Si)2NH] (3), [(C6F5)3CO]3Er(C6H5CH3) (4), [(C6F5)3CO]3Er(o-Me2NC6H4CH3) (5) and {[Ph(CF3)2CO]2Er(μ²-OC (CF3)2Ph)}2 (6). In compounds 1, 2, and 4, the Er3+ ion is four-coordinated and adopts a distorted trigonal pyramidal geometry, while in 3, 5, and 6, the coordination geometry of Er3+ is impacted by the presence of several relatively short Er...F distances, making them rather 6-coordinated. All compounds behave as field-induced Single Molecule Magnets (SMMs) and exhibit an Er3+ characteristic near infrared (NIR) emission associated with the 4I13/2 → 4I15/2 transition with a remarkably long lifetime going up to 73 µs, which makes them multifunctional luminescent SMMs. The deconvolution of the NIR emission spectra allowed us to provide a direct probe of the crystal field splitting in these compounds, which was correlated with magnetic data. [ABSTRACT FROM AUTHOR]

[Display omitted] Treatment of 1,4-diazabutadienes (DADs) of formula DippN=C(R)C(R)=NDipp (Dipp = 2,6-Pr 2 iC 6 H 3 , R = H or Me) with 2 or 1 equiv. of potassium metal in THF leads to the corresponding dianions (DAD2–) or radical anions (DAD•−), respectively. The subsequent salt metathesis between LnCl3 (Ln = Tb or Er) and the above dianions affords dimeric monochlorido complexes [(DAD2–)Ln(THF) 2 (μ-Cl)] 2 with bridging chlorine atoms between the lanthanides. The reaction of the radical anion species with LnCl3, if R = H, gives monomeric dichlorido complexes (DAD•−)Ln(THF) 2 Cl 2 ; however, if R = Me, the activation of one methyl group occurs, which in the reaction with TbCl3 leads to the formation of a product with shifted double bonds [DippN=C(Me)C(=CH 2)N(Dipp)]Tb(THF) 2 Cl 2. [ABSTRACT FROM AUTHOR]

A series of new octahedral bis‐3,6‐di‐tert‐butylcatecholates based on tin(IV) containing metal‐coordinated N‐donor ligands (substituted iminopyridines and diazabutadienes) has been synthesized and structurally characterized. The compounds, both solid and in solution, are intensely colored. They absorb in the visible region of the spectrum. Charge transfer between the catecholate donor and the diimine acceptor is responsible for the absorption. This observation is in good agreement with the DFT calculations and with the electrochemical studies carried out by CV. [ABSTRACT FROM AUTHOR]

Bis(phenolate) ligands with benzimidazole‐2‐ylidene (L1) and tetrahydropyrimidine‐2‐ylidene (L2) linkers proved to be suitable coordination environments for the synthesis of isolable Sc3+ chloro and alkyl complexes. The treatment of Sc(CH2SiMe3)3(THF)2 with equimolar amounts of [L1,2H3]Cl afforded chloro complexes L1,2ScCl(solv)2 (solv=THF, Py) in 76–85 % yields. L1,2ScCl(THF)2 were also prepared by the salt metathesis reactions of ScCl3 with [L1,2]Na2 generated from [L1,2H3]Cl and 3 equiv. of NaN(SiMe3)2 (−40 °C, THF) and isolated in somewhat lower yields (68–73 %). L2ScCl(THF)2 was subjected to the alkylation reaction with LiCH2SiMe3 affording alkyl derivative [L2Sc(CH2SiMe3)]2. This compound can be alternatively prepared by the subsequent reactions of [L2H3]Cl with equimolar amount of NaN(SiMe3)2 and Sc(CH2SiMe3)3(THF)2. In the dimeric alkyl compound [L2Sc(CH2SiMe3)]2, one of the phenoxide groups of the dianionic ligand is coordinated to one scandium center, while the second one features μ‐bridging coordination with two metal centers. [ABSTRACT FROM AUTHOR]

We report the synthesis, crystal structures, and magnetic and theoretical investigations of five erbium complexes based on halogenated ligands with the respective formulas trans-[Er(L1)3(THF)2] (1), trans-[Er(L2)3(Ph3PO)2] (2), fac-[Er(L3)3(THF)3] (3), fac-[Er(L4)3(Ph3PO)3] (4), and [Er(L5)3] (5) (L1 = OCPh2(CF2Cl), L2 = OCPh(CF3)2, L3 = OCH(C6F5)2, L4 = OCHMe(C6F5), L5 = 1,8-dibromo-3,6-di-tert-butylcarbazol-9-ide, THF = tetrahydrofuran). Modulation of the experimental conditions allows controlling the coordination geometry of the resulting complexes. While 1 and 2 adopt a trigonal bipyramidal geometry, 3 and 4 exhibit a distorted octahedral arrangement. In contrast, 5 exhibits a triangular coordination geometry. Magnetic investigations in line with theoretical calculations reveal that only the three-coordinated complex 5 exhibits a zero-field slow relaxation of the magnetization, while compound 1 demonstrates field-induced relaxation dynamics. [ABSTRACT FROM AUTHOR]

The reduction of 2‐[(2,6‐diisopropylphenyl)imino]acenaphthen‐1‐one (dpp‐MIAN) with metallic calcium in THF affords tetrameric [(dpp‐MIAN)Ca(THF)]4 (1). A further addition of dpp‐MIAN to complex 1 leads to the formation of paramagnetic species [(dpp‐MIAN)3Ca]2Ca (2). Both complexes were characterized by X‐ray diffraction. Complex 1 is active towards phenylacetylene and acetylene at temperatures above 80 °C. As a result, cycloaddition products are formed. Their hydrolysis results in a release of the dpp‐MIAN ligand with an attached phenylethynyl or ethynyl moiety to the carbonyl C atom. Complexes 1 and 2 demonstrate catalytic activity in the polymerization of L‐lactide both in solution and in bulk. [ABSTRACT FROM AUTHOR]

A series of bis(alkyl) complexes {(tBu)C[N(2,6-Me2C6H3)]2}Ln(CH2SiMe3)2(THF)n (Ln = Y, n = 1 (1); Ln = Sc, n = 1 (2)), {2-[Ph2P(O)]C6H4NC(tBu)N(2,6-Me2C6H3)}Sc(CH2SiMe3)2 (3), {2-[Ph2P(NPh)]C6H4NC(tBu)N(2,6-Me2C6H3)}Sc(CH2SiMe3)2 (4) coordinated by bidentate (N,N) and tridentate (N,N,O; N,N,N) amidinate ligands are synthesized using an alkane elimination approach. Yttrium complex 1 demonstrated a half-life of ∼2.5 days at room temperature in benzene-D6 (C6D6) solution, whereas scandium complexes proved to be much more stable (25 d (2), 30 d (3) and 42 d (4)). Complexes 1–4 as a part of ternary catalytic systems 1–4/TB, HNB/AlR3 (AlR3 = AliBu3, AliBu2H; TB = [Ph3C][B(C6F5)4], HNB = [PhNHMe2][B(C6F5)4]) demonstrated high catalytic activity in isoprene polymerization and enable 80%–100% conversion of 1000 equivalents of monomer into polymer at 25 °C within 3–180 min. The isolated polyisoprenes feature predominantly cis-1,4-regularity (69.2%–87.3%) and polydispersities Mw/Mn = 2.26–8.92. Moreover, the binary (2/TB) and ternary (1–4/TB/10 AliBu3) systems initiate 1-heptene polymerization providing 40%–100% conversion of 500 equivalents of monomer in 24 h at 25 °C giving polymer samples with Mn = 1.55–190.2 × 103 and Mw/Mn = 1.55–3.87. [ABSTRACT FROM AUTHOR]

Treatment of toluene solutions of (dpp-bian)M (dpp-bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene; M = Li, Na, K) with 4,4′-bipyridine (4,4′-bipy) affords coordination polymers [(dpp-bian)Li(4,4′-bipy)]n (1), [(dpp-bian)Na(4,4′-bipy)2]n (2) and [(dpp-bian)K(4,4′-bipy)]n (3). Compounds 1–3 have been characterized by elemental analysis and thermogravimetry (TGA) as well as IR, UV-vis and ESR spectroscopy. According to single crystal X-ray analysis, products 1 and 2 present 1D coordination polymers, while product 3 reveals a 2D architecture. [ABSTRACT FROM AUTHOR]

The reactions of 2-imino-2,3-dihydrobenzoxazole LH with M[N(SiMe3)2]2(THF)2 (M = Yb and Ca) and Y(CH2SiMe3)3(THF)2 proceed with the opening of the dihydrobenzoxazole ring and the elimination of HN(SiMe3)2 or SiMe4. Besides, in the case of Yb[N(SiMe3)2]2(THF)2, an electron transfer from Yb(II) to L takes place and Yb(III) complex 1 is coordinated by a dianionic phenolate ligand containing a pendant radical-anionic diazabutadiene fragment form. When LH is reacted with Ca[N(SiMe3)2]2(THF)2, C–H bond activation of a methyl fragment by imino nitrogen occurs and affords a dimeric calcium complex 2. In 2, the phenolate ligand is dianionic due to the presence of the amido-imino fragment [R–N＝C(CH3)–C(＝CH2)–NR′]− (R = 2,4-tBu2-C6H2O; R′ = 2,6-iPr2C6H3). In situ generated ate-complex {Na(Et2O)n}{Ca[N(SiMe3)2]3} also enables C–H bond activation, however the dianionic phenolate ligand in the resulting complex 3 contains an amido-imino fragment [R–N–C(＝CH2)–C(CH3)＝NR′]− featuring the sequence of N–C and N＝C bonds opposite to that in 2. The reaction of Y(CH2SiMe3)3(THF)2 with LH affords mono(alkyl) yttrium complex 4. 4 contains a dianionic amido-imino phenolate ligand resulting from the migration of one alkyl group to the C＝N bond [R–N–C(Me)(CH2SiMe3)–C(Me)＝NR′]. 4 undergoes slow intramolecular C–H bond activation of the residual CH3 group to afford a yttrium complex coordinated by a trianionic diamido-phenolate ligand [R–N–C(Me)(CH2SiMe3)–C(＝CH2)NR′]. [ABSTRACT FROM AUTHOR]

We report the synthesis, crystal structures and magnetic investigations of four octahedral dysprosium complexes based on silanolate or stannanolate ligands of respective formula cis-[Dy(OSiPh3)2(THF)4][BPh4]·THF·C6H6 (1), cis-[Dy(OSnPh3)2(THF)4][BPh4]·THF·C6H6·C6H14 (2), fac-[Dy(OSiPh3)3(THF)3]·THF (3) and fac-[Dy(OSiPh3)3(bipy)(THF)]·THF (4) (where THF = tetrahydrofuran, Ph = phenyl, bipy = 2,2′-bipyridine). Whereas complexes 1–3 exhibit a field-induced slow relaxation of the magnetization, 4 is a zero-field single-molecule magnet, which could be rationalized by the introduction of the bidentate bipy ligand providing a more important linearity of the (Si)O–Dy–O(Si) angle through distortion of the coordination sphere. [ABSTRACT FROM AUTHOR]

We report the synthesis and structures of three luminescent dysprosium(III) complexes based on fluorinated alkoxide ligands of formulas [Dy(L1)2(THF)4][BPh4]·0.5THF (1), [Dy(L2)2(THF)5][BPh4]·2.5THF (2) and [Dy(L3)2(THF)5][BPh4]·2THF (3) (L1 = (CF3)3CO−, L2 = C6F5C6F4O−, L3 = C6F5C(CH3)O−). Despite the different dysprosium ion geometries (octahedral vs. distorted pentagonal bipyramidal), these systems exhibit a single-molecule magnet (SMM) behavior, but with distinct relaxation dynamics. Moreover, a typical dysprosium-based luminescence is observed for the three complexes, which make them bifunctional magneto-luminescent SMMs. Remarkably, complex 3 exhibits a high anisotropy barrier of 1469 cm−1 and a blocking temperature of 22 K, making it one of the most performant alkoxide-based SMMs with the highest blocking temperature for a luminescent SMM. [ABSTRACT FROM AUTHOR]

Bis(alkyl) complexes [(2,6‐Me2C6H3)NC(tBu)N(C6H4−2‐OMe)]M(CH2C6H4−2‐NMe2)2 (M=Sc (4), Y (5)), [(2‐OMe−C6H4N)2C(tBu)]Y(CH2SiMe3)2(THF)2 (6), supported by N,N,O‐tridentate (4, 5) and N,N,O,O‐tetradentate (6) amidinate ligands were synthesized by the alkane elimination approach reacting tris(alkyl) rare‐earth species M(R)3Xn (R=Me3SiCH2, X=THF, n=2; R=CH2C6H4−2‐NMe2, n=0) with one equivalent of amidine (2,6‐Me2C6H3)N=C(tBu)−NH(C6H4−2‐OMe) (1) or (2‐MeO−C6H4)N=C(tBu)−NH(C6H4−2‐OMe) (2). The reaction of amidine 2 with equimolar amount of Y(CH2C6H4−2‐NMe2)3 in toluene unexpectedly results in the addition of N,N‐dimethylaminobenzyl group to C=N bond of one amidinate fragment, ligand disproportionation and the formation of novel bis(amide)amidinate complex [(2‐OMe−C6H4N)2C(tBu)CH2C6H4−2‐NMe2]Y[(2‐OMe−C6H4N)2C(tBu)] (7). Complexes 4–6 were evaluated as catalysts for α‐olefins and isoprene polymerization. [ABSTRACT FROM AUTHOR]

New diphenylmethane [4‐tBu‐2‐(C3H2N2Me‐1)C6H3]2CH2 (1) bearing pendant imidazolyl groups in ortho‐positions of aromatic rings of diphenylmethane skeleton was synthesized using Stille cross‐coupling reaction between bis(4‐(tert‐butyl)‐2‐iodophenyl)methane and Bu3Sn(C3H2N2Me) in the presence of Pd(PPh3)4. Potassium diphenylmethanide [{[4‐tBu‐2‐(C3H2N2Me‐1)C6H3]2CH}K(OEt2)]2 (2K) was prepared by treatment of 1 with an equimolar amount of Lochmann‐Schlosser super base. Rare‐earth metal heteroalkyl complexes {[4‐tBu‐2‐(C3H2N2Me‐1)C6H3]2CH}Ln(CH2SiMe3)2(THF)n (Ln = Sc, n = 0 (2Sc); Y, n = 1 (2Y)) with NCsp3N pincer type diphenylmethanido ligand were synthesized by the selective sp3 CH‐bond activation of the central CH2 group in 1 by Ln(CH2SiMe3)3(THF)2. According to the X‐ray data the diphenylmethanido ligands in 2K and 2Sc perform a tridentate pincer‐type κ3‐N,C,N coordination. Complexes 2Ln were evaluated as catalysts for isoprene polymerization and hydrosilylation of alkenes and alkynes. [ABSTRACT FROM AUTHOR]

We report the synthesis, structure and magnetic investigations of two new Dy3+ homoleptic ate-complexes based on different ene-diamido ligands [K(THF)2][Dy(DAD2R)2] (R = H (1), Me (2) DAD2R = [2,6-iPr2C6H3N–CR＝CR–NC6H3iPr2-2,6] showing K+/arene interactions. Magnetic investigations reval that both compounds exhibit a zero-field single-molecule magnetic relaxation mainly governed by a Raman process. [ABSTRACT FROM AUTHOR]

Complexes [(2-MeOC6H4N)C(tBu)N(2,6-Me2C6H3)]2LnN(SiMe3)2 (Ln = Y (2), Sm (3)) and [(2-MeOC6H4N)C(tBu)N(2,6-Me2C6H3)]CaN(SiMe3)2(THF) (4) were obtained by reacting Ln[N(SiMe3)2]3 (Ln = Y, Sm) or Ca[N(SiMe3)2]2 with [2-MeOC6H4N]C(tBu)NH(2,6-Me2C6H3) (1) in 1 : 2 or 1 : 1 molar ratios, respectively, and were isolated in 76 (2), 68 (3) and 63% (4) yields. In complexes 2 and 3, the amidinate ligands are tridentate due to the intramolecular coordination of the 2-MeO-group to the metal center. Complex 4 exhibits an unusual κ2-N,O:η3-arene coordination mode of the amidinate ligand. Complexes 2–4 initiate ring-opening polymerization (ROP) of rac-lactide (rac-LA) and ε-caprolactone (ε-CL) at room temperature and allow for conversion of 1000 equivalents of monomer into polymer within 180–230 min for rac-LA and 1–7 min for ε-CL. Complexes 2 and 3 enable the formation of atactic polymers (Pr = 0.52–0.58) featuring moderate polydispersities (PDI = 1.30–3.06 for polylactide; PDI = 1.48–2.84 for polycaprolactone). When 4 was applied, PDIs were somewhat narrower (1.28–2.43 for PLA; 1.24–2.48 for PCL). Application of the initiating systems 2–4/iPrOH (1 : 1) leads to the formation of the polymers having close values of the experimental and calculated molecular weights however does not affect strongly the molecular weight distribution. In the presence of 5 equivalents of iPrOH, complexes 2–4 initiate immortal polymerization for both rac-LA and ε-CL. The polymers feature a good match with the experimental and calculated Mn but have moderate polydispersities (PDI = 1.28–1.90 for polylactide; PDI = 1.24–1.96 for polycaprolactone). [ABSTRACT FROM AUTHOR]

Amido [ButC(NC6H4‐2‐OMe)2]2LnN(SiMe3)2 (Ln = Y (3), Nd (4)) and borohydrido complexes [ButC(NC6H4‐2‐OMe)2]2LnBH4 (Ln = Y (5), Nd (6)) coordinated by new amidinate ligand bearing two pendant anisolyl groups are synthesized. According to X‐ray analysis in complexes 3 and 4 one amidinate ligand is coordinated to the Ln3+ cation in a bidentate fashion (κ2‐NN), while the second one is tetradentate (κ4‐NNOO). At the same time in borohydrido neodymium complex 6 the amidinate ligands demonstrate κ4‐NNOO and κ3‐NNO coordination modes. Complexes 3–6 proved to be efficient initiators for ring‐opening polymerization of rac‐lactide and allow for achieving quantitative conversion of 500 equivalents of monomer into polymer in 0.3–4.5 h at 25 °C. The polymerization of ε‐caprolactone initiated by 3–6 proceeds much faster under similar conditions. [ABSTRACT FROM AUTHOR]

The reactions of [(Me3Si)2N]2Ca(thf)2 with amidines 2‐(Ph2P=NPh)C6H4NHC(tBu)=N(2,6‐R2C6H3) {R = iPr (L1H); R = Me (L2H)} afford heteroleptic calcium amido complexes [2‐(Ph2P=NPh)C6H4NC(tBu)=N(2,6‐R2C6H3)]Ca[N(SiMe3)2](thf) {R = iPr (1); R = Me (2)} featuring tridentate coordination of the amidinate ligands. Complexes 1 and 2 proved to be efficient catalysts for intermolecular hydrophosphination of styrene, α‐methylstyrene, divinylbenzene and phenylacetylene with Ph2PH and PhPH2. Compounds 1 and 2 exhibit high catalytic activity in the ring‐opening polymerization of ε‐caprolactone and enable quantitative conversion of 500 equiv. of monomer in 5 seconds (22 °C). Polymerization of rac‐lactide initiated by 1 and 2 proceeds much slower: 52–72 % conversion ([M]0/[Ca]0 = 100) was reached in 12 h (20 °C). The obtained polymers are characterized by narrow polydispersities (Mw/Mn = 1.22–1.28). Catalytic activity of complexes 1 and 2 in rac‐lactide polymerization increases significantly in the presence of 1–3 equiv. of iPrOH. Nearly quantitative (86–98 %) conversion of 100 equiv. of monomer was reached in 1 h and the obtained polymer samples were characterized by relatively narrow polydispersity (Mw/Mn = 1.51–1.68). [ABSTRACT FROM AUTHOR]

We report the investigation of synthesis, structure and magnetic properties of a series of homoleptic Ln(III) complexes coordinated by radical-anionic iminopyridine ligands of general formula [Ln(IPy)3]·solv (IPy = iminopyridine; Ln = Tb, Dy, Er, Y, Gd). The dysprosium analogue exhibits a zero-field Single-Molecule Magnet (SMM) behavior. [ABSTRACT FROM AUTHOR]

Lithium silylamides 1,8-C10H6[N(SiMe3)Li(L)]2 (L = Et2O (UGRAPHIC DISPLAY="INLINE" ID="UGT1" SRC="UGT1"/); L = TMEDA (1TMEDA)), when treated with PhC≡N, formed the adducts 1,8-C10H6[N(SiMe3)Li(N≡CPh)(OEt2)][N(SiMe3)Li(OEt2)] (UGRAPHIC DISPLAY="INLINE" ID="UGT2" SRC="UGT2"/) and 1,8-C10H6[N(SiMe3)Li(N≡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 UGRAPHIC DISPLAY="INLINE" ID="UGT3" SRC="UGT3"/ and 2TMEDA (THF, 4 h, 40 °C) resulted in benzonitrile insertion and formation of new dianionic amido-amidinate ligands. The reactions of UGRAPHIC DISPLAY="INLINE" ID="UGT4" SRC="UGT4"/ 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. [ABSTRACT FROM AUTHOR]

The salt-metathesis reactions of anhydrous LnCl3 (Ln = Y, Er) with [1,3-C6H4{NC(Ph)NSiMe3}2Li2(thf)2]2 (1; thf = tetrahydrofuran) in a 2:1 molar ratio in thf afford tris(amidinate) complexes [(1,3-C6H4{NC(Ph)NSiMe3}2)3Y(thf)Y(μ-Cl)Li(thf)3] (3) and [(1,3-C6H4{NC(Ph)NSiMe3}2)3Er2(μ-Cl)Li(thf)3] (4), which feature bridging coordination of the amidinate ligands to two Ln3+ ions. The reactions of the dilithium derivative of the related bis(amidine) with a 2,6-pyridinediyl linker, [2,6-C5H3N-{NC(tBu)N(2,6-Me2C6H3)}2]2-, with LnCl3 (Ln = Y, Er) result in the formation of mononuclear chlorido bis(ligand) ate complexes [{(2,6-C5H3N)(NC{tBu}N{2,6-Me2C6H3})2}({2,6-C5H3N}{NC(tBu)N-(2,6-Me2C6H3)}{NC(tBu)NH(2,6-Me2C6H3)})LnCl][Li(dme)3] [Ln = Y (5), Er (6); dme = 1,2-dimethoxyethane]. The Ln3+ ions in these complexes are coordinated by one dianionic tridentate amidopyridinate-amidinate ligand, and the second ligand is a monoanionic amidopyridinate. The reaction of YbCl3 with [(Me2Si-{NC(Ph)N(2,6-iPr2C6H3)}2)2Li3][Li(thf)4], which contains a short SiMe2 linker, in a 2:1 molar ratio in thf afforded the bis-(amidinate)chloridoytterbium complex [(Me2Si{NC(Ph)N(2,6-iPr2C6H3)}2)2(Yb2Cl)(μ-Cl)2Li(thf)3] (8). The magnetic properties of 4 were investigated through superconducting quantum interference device (SQUID) magnetometry. [ABSTRACT FROM AUTHOR]

Bis(amido)–TiIV and –ZrIV complexes stabilized by the bis(amidinate) ligands {C6H4-1,2-[NC(tBu)N(2,6-R2C6H3)]2}M(NMe2)2 [M = ZrIV, R = Me (3), R = iPr (4); M = TiIV, R = Me (5), R = iPr (6)] and {C6H4-1,2-[NC(tBu)N(2,6-Me2C6H3)]2}Zr(NMe2)3H (3·HNMe2) were prepared in fairly good yields by treating a (bis)amidine ligand C6H4-1,2-[NC(tBu)N(2,6-R2C6H3)H]2 [R = Me (1), iPr (2)] with an equimolar amount of the metal precursor M(NMe2)4 (M = ZrIV, TiIV). The salt metathesis reactions between equimolar amounts of the sodium amidinates C6H4-1,2-[NC(tBu)N(2,6-R2C6H3)]2Na2 and ZrCl4(thf)2 were also scrutinized to synthesize the corresponding ZrIV bis(amidinate) dichlorides {C6H4-1,2-[NC(tBu)N(2,6-R2C6H3)]2}ZrCl2 [R = Me (7), iPr (8)]. The coordination mode of the ligand to the MIV ions was strongly affected by the steric hindrance of the amidinate ligand (Me- vs. iPr-substituted aniline moieties) as well as by the nature of the ancillary groups bound to the metal center (NMe2 vs. Cl). The bis(amido) ligand with the 2,6-Me2C6H3 substituents at the amidinate nitrogen atoms coordinates to the zirconium ion in a tetradentate fashion both in solution and in the solid state (3 and 3·HNMe2). The compounds containing the bulkier 2,6-iPr2C6H3 units prefer a tridentate coordination mode (4). With the smaller TiIV ion, the bis(amidinate) ligands from this series are tridentate in the solid state (5 and 6), whereas they reversibly switch their denticity from tridentate to tetradentate (κ3 vs. κ4) in solution depending on the temperature. The ZrIV complex 4, featuring the bulkier bis(amidinate) ligand 2, shows a behavior similar to that of its TiIV analogue, that is, a tridentate ligand coordination in the solid state and a temperature-induced denticity change in solution. The standard thermodynamic parameters for the κ3/κ4 interconversions of the two model compounds 4 and 5 in [D8]toluene solution were determined from the respective linear van't Hoff plots. Finally, the ZrIV bis(chloride) complexes 7 and 8 invariably show a tetracoordinate mode for their bis(amidinate) ligands (1 and 2) in solution and in the solid state. [ABSTRACT FROM AUTHOR]

Graphical abstract A salt metathesis reaction of anhydrous DyCl 3 and [1,3-C 6 H 4 {NC(Ph)N(SiMe 3)} 2 Li 2 (THF) 2 ] in THF affords the complex [1,3-C 6 H 4 {NC(Ph)N(SiMe 3)} 2 ] 3 Dy 2 regardless of a ratio between reagents. The assembling of a binuclear core results from a spanning coordination of the amidinate fragments of three μ-bridging ansa -bis(amidinate) ligands to two Dy3+ ions. The magnetic properties of the product were studied by SQUID magnetometry in a temperature range of 1.8–300 K. [ABSTRACT FROM AUTHOR]

The reactions of bis(pyrazolyl)methanes CH2(C3HN2R2-3,5)2 (R = Me, tBu) with Y(CH2SiMe3)3(THF)2 and LY(CH2SiMe3)2(THF)n (L = amidopyridinate (Ap'), amidinate (Amd), tridentate amidinate bearing 2-methoxyphenyl pendant in a side arm (AmdOMe) and pentamethylcyclopentadienyl (Cp*); n = 0, 1) were investigated. CH2(C3HN2tBu2-3,5)2 turned out to be inert in these reactions, while less bulky CH2(C3HN2Me2-3,5)2 easily undergoes metalation by yttrium alkyls. The reaction of Y(CH2SiMe3)3(THF)2 with CH2(C3HN2Me2-3,5)2 regardless of the molar ratio of the reagents affords a homoleptic tris(alkyl) species, Y[CH(C3HN2Me2-3,5)2]3 (1). However, the reactions of equimolar amounts of LY(CH2SiMe3)2(THF)n and CH2(C3HN2Me2-3,5)2 occur selectively with replacement of a sole CH2SiMe3 fragment and afford the related heteroalkyl complexes LY(CH2SiMe2)[CH(C3HN2Me2-3,5)2](THF)n (L = Ap', n = 1 (6); Amd, n = 0 (7); AmdOMe, n = 1 (8); Cp*, n = 1 (9)) in good yields. The second equivalent of CH2(C3HN2Me2-3,5)2 does not react with heteroalkyl yttrium complexes. The X-ray studies revealed that in complexes 1 and 6-9 the bis(pyrazolyl)methyl ligands are bound to the yttrium centers in a similar fashion via one covalent Y-C and two coordination Y-N bonds. Thermal decomposition of complexes 6-9 (C6D6, 80 °C) as evidenced by 1H NMR spectroscopy resulted in SiMe4 elimination, while no activation of the C-H bonds of bis(pyrazolyl)methyl ligands was detected. When 6 was treated with an equimolar amount of PhSiH3, only the YCH2SiMe3 bond selectively underwent s-bond metathesis and a dimeric yttrium alkyl-hydrido complex, {Ap'Y[CH(C3HN2Me2-3,5)2](µ²-H)}2 (10), was formed. The reaction of 6 with 2,6-diisopropylaniline also resulted in the selective protonation of the YCH2SiMe3 bond and cleanly afforded alkyl-anilido complex Ap'Y(NHC6H3iPr2-2,6)[CH(C3HN2Me2-3,5)2](THF) (11). The ternary catalytic systems 6-9/borate/AliBu3 (borate = [HNMe2Ph][B(C6F5)4], [Ph3C][B(C6F5)4]; [Ln]:[borate]:[AliBu3] = 1:1:10) demonstrated moderate catalytic activity in isoprene polymerization; they allow quantitative conversion into polymer of up to 1000 equiv of monomer in 2-4 h. The best activity and 1,4-cis selectivity (83.5%) were demonstrated by amidinato complex 8. [ABSTRACT FROM AUTHOR]

Introduction of four tBu groups into a carbazol-ylframework leads to switching of the metal–ligand bonding inthe Ln(II) and Ca complexes from σ to π. Complexes [(tBu4Carb)2Ln] (Ln = Sm, Eu, Yb, Ca)are amido analogues of metallocenes, which adopt the sandwich structureswith parallel disposition of the aromatic ligands and strong contributionof η3-mode into η5metal–ligandbonding. The DFT calculations demonstratedthat the geometry is due to steric effects (presence of the bulky tBu groups) as well as the maximization of the overlap betweenthe Sm 4f orbital and the π-type nitrogen lone pairof the carbazol-yl ligand. Coordination of DME to the metal centersin [(tBu4Carb)2M] (M = Sm,Yb) results in the heterolytic dissociation of the metal–ligandπ-bond and the formation of ionic complexes [tBu4Carb–]2[Ln2+(DME)n]. [ABSTRACT FROM AUTHOR]

Neutral YIII 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 Ph3C+[B(C6F5)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. [ABSTRACT FROM AUTHOR]

A series of lanthanide monoborohydrido complexes {C6H4-1,2-[NC(R)NR′]2}Ln(BH4)(L) n (Ln = Y, Nd, Sm; R = tBu, Ph; R′ = 2,6-Me2C6H3, SiMe3; L = dme = dimethoxyethane, n = 1; L = thf, n = 2), in which lanthanides are coordinated by bulky ansa-bis(amidinato) ligand systems with a conformationally rigid o-phenylene linker ({C6H4-1,2-[NC(R)NR′]2}2-), were synthesized by the salt metathesis reactions of equimolar amounts of Ln(BH4)3(thf)3 and {C6H4-1,2-[NC(R)NR′]2}X2(thf) n (X = Li, Na) in thf. X-ray diffraction studies revealed that the complexes are monomeric. Depending on the denticity of the donor ligand (L = dme or thf), the terminal borohydrido ligand coordinated to the metal ion can be located in either an equatorial (L = thf) or an apical (L = dme) position. All complexes are efficient catalysts for the ring-opening polymerization of rac-lactide, which allows to convert up to 1000 equiv. of monomer into a polymer at room temperature within 10-150 min and affords atactic polylactides with high molecular weights and moderate molecular-weight distributions (1.28-2.16). Yttrium-borohydrido complexes coordinated by the {C6H4-1,2-[NC( tBu)N(2,6-Me2C6H3)]2}2- ligand system showed enhanced catalytic activity compared to that of the analogue complexes containing the {C6H4-1,2-[NC(Ph)NSiMe3]2}2- ligand. The obtained borohydrido complexes catalyze the hydrophosphonylation of benzaldehyde at room temperature with good reaction rates. [ABSTRACT FROM AUTHOR]

A monoanionic amido–imino ligand system [(2,6-iPr2C6H3)N=C(Me)C(=CH2)N(C6H3-2,6-iPr2)]− was successfully employed for the synthesis of monomeric dichloro [(2,6-iPr2C6H3)N=C(Me)C(=CH2)N(C6H3-2,6-iPr2)]LnCl2(THF)2 (Ln = Y, 2Y; Lu, 2Lu) and bis(alkyl) [(2,6-iPr2C6H3)N=C(Me)C(=CH2)N(C6H3-2,6-iPr2)]Ln(CH2SiMe3)2(THF) (Ln = Y, 4Y; Lu, 4Lu) species of yttrium and lutetium. Dichloro complexes 2Y and 2Lu turned out to be unstable in aromatic solvents. The ligand symmetrization reaction in the case of 2Y affords the yttrium complex coordinated by dianionic [(2,6-iPr2C6H3)NC(=CH2)C(=CH2)N(C6H3-2,6-iPr2)]2− ligand, (2,6-iPr2C6H3)N=C(Me)C(Me)=N(C6H3-2,6-iPr2) and YCl3. On the contrary, bis(alkyl) species 4Y and 4Lu are rather stable and do not undergo such a transformation or thermal decomposition. The treatment of complex 4Y with DME resulted in C–O bond cleavage and the formation of a dimeric methoxy-alkyl species {[(2,6-iPr2C6H3)N=C(Me)C(=CH2)N(C6H3-2,6-iPr2)]Y(CH2SiMe3)(μ-OMe)}2 (5). The ternary systems 4Ln/AliBu3/borate (borate = [HNMe2Ph][B(C6F5)4] and [CPh3][B(C6F5)4]; molar ratio 1 : 10 : 1) performed high catalytic activity in isoprene polymerization and ability to convert into polymer 1000–5000 equivalents of isoprene in 20–120 min with quantitative conversion. The obtained polyisoprenes possessed high molecular weights (2.9 × 104–4.1 × 104) and moderate polydispersities (2.14–3.52). Predominant 3,4-regioselectivity (up to 78%) was observed. [ABSTRACT FROM AUTHOR]

Bis- o -quinone with resorcinol as a linker forms binuclear metallamacrocycles with Te and Ni. SC XRD study indicates that both metallamacrocycles have no cofacial orientation of bis-dioxolene metal fragments. It occurs due to saturation of coordination sphere with electron lone pairs in Te complex and with phenanthroline in Ni one. [Display omitted] Ditopic ligand containing two 3,6-di- tert -butyl- o -benzoquinonato fragments linked through 4-position by resorcinol bridge was utilized for synthesis of metallamacrocyclic complexes with tellurium and nickel. Both compounds consist of two metal-centered coordination units connected by two bis-dioxolenes. Coordination units have distorted octahedral geometry. Four coordinated oxygen atoms of dioxolenes form uncompleted distorted octahedron environment. The lacking sites in octahedron coordination sphere are filled with electronic lone pairs in the case of tellurium and phenanthroline ligand in the case of nickel. In contrast to previously described cobalt and nickel complexes with the same bis-dioxolene, metal units are situated not cofacially. The reason of this is saturation of coordination sphere of central atom until octahedron which excludes coordination with internal solvent molecule which can connect both metals. [ABSTRACT FROM AUTHOR]

Correction for ‘Amido Ca(ii) complexes supported by Schiff base ligands for catalytic cross-dehydrogenative coupling of amines with silanes’ by Natalia V. Forosenko et al., Dalton Trans., 2018, 47, 12570–12581. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Two synthetic approaches to the new three-decker Yb(II) complex [CpBn5Yb(DME)]2[μ-C10H8] (1) were successfully employed: the reaction of [CpBn5Yb(DME)(μ-I)]2 (2) with 2 molar equiv of [C10H8]-·K in DME and the reaction of [YbI(DME)2]2[μ-C10H8] (3) with CpBn5K in a 1:2 molar ratio in DME. Complex 1 was proved to be a Yb(II) binuclear triple-decker complex containing a dianionic naphthalene ligand bridging two CpBn5Yb(DME) fragments in a μ-η4:η4 fashion. An oxidative substitution of (C10H8)2- by trans-(1E,3E)-1,4-diphenylbuta-1,3-diene afforded the three-decker Yb(II) complex [CpBn5Yb(DME)]2(μ-η4:η4 -PhCHCHCHCHPh) (4) with a dianionic μ-η4:η4-bridging diphenylbutadiene ligand and naphthalene. The reaction of 1 with excess P4 also occurs with oxidation of (C10H8)2-, whereas Yb remains divalent. The reaction results in the formation of the trinuclear Yb(II) complex with a μ-bridging P7 3- ligand [CpBn5Yb(DME)]3(P7) (5). Protonation of the Yb-C10H8 bond in 1 with PhPH2 (1:2 molar ratio) afforded the dimeric phosphido complex [CpBn5Yb(THF)(μ2-PHPh)]2 (6) in 64% yield, while an attempt to obtain a phosphinidene Yb(II) species by reacting equimolar amounts of 1 and PhPH2 in DME resulted in the isolation of the metallocene complex CpBn5 2Yb(DME) (7). [ABSTRACT FROM AUTHOR]

The reactions of bis(trimethylsilylmethyl)yttrium complexessupported by bulky amidopyridinate (Ap) and amidinate (Amd) ligands(LY(CH2SiMe3)2(THF)n: L = Ap, n= 1 (1); L = Amd, n= 1 (2)) with 2,6-diisopropylaniline andphenylacetylene were performed. The reaction of 1withan equimolar amount of 2,6-diisopropylaniline occurs with TMS eliminationand affords an yttrium alkyl anilido species which was isolated asa DME adduct, ApY(CH2SiMe3)(NH-2,6-iPr2C6H3)(DME) (3).The protonolysis of 3with phenylacetylene results inthe alkynyl anilido derivative ApY(CCPh)(NH-2,6-iPr2C6H3)(DME) (6).The treatment of complexes 3and 6with2,2′-bipy leads to the formation of the bis(anilido) derivativeApY(NH-2,6-iPr2C6H3)2(bipy) (5). The formation of a dimericcomplex containing two ApY fragments linked by two μ2-alkynyl groups and a μ-η2:η2-butatrienediyl fragment, [{AmdY(μ2-CCPh)}2(μ2-η2:η2-PhCCCCPh)] (7), was observed in the reaction of 2with 2 equiv of phenylacetylene. [ABSTRACT FROM AUTHOR]

ansa-Bis(amidinate) ligands with a rigid o-phenylene linker, C6H4-1,2-{NC(tBu)N(2,6-R2C6H3)H}2(R = Me (1), iPr (2)), were successfully employed for the synthesis of rare-earth chloroand alkyl species. The reaction of dilithium derivatives of 1and 2with LnCl3(Ln = Y, Lu) affordedthe monomeric bis(amidinate) chloro lanthanide complexes [C6H4-1,2-{NC(tBu)N(2,6-R2C6H3)}2]Y(THF)(μ-Cl)2Li(THF)2(R = Me (3), iPr(5)) and [C6H4-1,2-{NC(tBu)N(2,6-Me2C6H3)}2]LuCl(THF)2(4). Bis(amidinate) ligandsin complexes 3and 4are coordinated tothe metal atoms in a tetradentate fashion, while the bulkier ligandin 5is tridentate. The alkane elimination reactionsof 1and 2with equimolar amounts of (Me3SiCH2)3Ln(THF)2(Ln = Y,Lu) allowed us to obtain the monoalkyl complexes [C6H4-1,2-{NC(tBu)N(2,6-R2C6H3)}2]Ln(CH2SiMe3)(THF)n(Ln = Y, R = Me, n= 1(6); Ln = Lu, R = Me, n= 1 (7); Ln = Y, R = iPr, n= 2 (8)). The kinetics of thermal decomposition of complexes 6–8were measured, and for 6the activation energy was obtained from the temperature dependenceof the rate constants (Ea= 67.0 ±1.3 kJ/mol). Complexes 6and 7turned outto be inert toward H2and PhSiH3. Surprisingly,complex 8was inert toward H2and PhSiH3but rapidly cleaved C–O bonds of DME. The reactionresulted in the formation of the methoxy complex {[C6H4-1,2-{NC(tBu)N(2,6-iPr2C6H3)}2]Y(μ2-OMe)]}2(μ2-DME) (9) andmethyl vinyl ether. [ABSTRACT FROM AUTHOR]

• Monoanionic β-triketiminate ligands feature bidentate coordination mode and are coordinated to a metal center only through two nitrogen atoms. • The ternary systems based on these complexes exhibit catalytic activity in isoprene polymerization. • The ternary systems provide very high content of cis -1,4 units (98.9%). Deprotonation of β-triketimines (2,6-Me 2 C 6 H 3 N = CMe) 3 CH (1), (2,6-Me 2 C 6 H 3 N = CMe) 2 CH(2-MeOC 6 H 4 N = C t Bu) (2), (2,6-Me 2 C 6 H 3 N = CMe) 2 CH(2,6-Me 2 C 6 H 3 N = C t Bu) (3) by equimolar amount of n -BuLi afforded lithium triketiminate complexes [(2,6-Me 2 C 6 H 3 N = CMe) 3 C]Li(THF) (4), [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]Li(THF) 2 (5), [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]Li(THF) 2 (6) in 70–80% yields. The salt metathesis reactions of LnCl 3 (Ln = Y, Nd) with 6 lead to the formation of neutral triketiminate dichloro complexes [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]LnCl 2 (THF) 2 (Ln = Y (7), Nd (8)) in 78 and 70% yields, while the analogous reaction of YCl 3 with 5 resulted in triketiminate yttrium chloro ate complex [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]Y(THF)Cl(µ2-Cl) 2 Li(THF) 2 (9). The reactions of the potassium derivatives of the related triketimines 2 , 3 with YbI 2 (THF) 2 resulted in the formation of mononuclear triketiminate iodo Yb(II) complexes [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]YbI(THF) 2 (10) and [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]YbI(TMEDA) (11). X-ray analysis revealed that in 4 and rare-earth metals complexes 7 – 11 the monoanionic β-triketiminate ligands [(2,6-Me 2 C 6 H 3 N = CMe) 3 C]−, [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2-MeOC 6 H 4 N = C t Bu)]−, [(2,6-Me 2 C 6 H 3 N = CMe) 2 C(2,6-Me 2 C 6 H 3 N = C t Bu)]− feature bidentate coordination mode and are coordinated to a metal center only through two nitrogen atoms. The ternary systems 7–9 /Al i Bu 3 /[CPh 3 [B(C 6 F 5) 4 exhibit catalytic activity in isoprene polymerization, allowing to carry out polymerization of 1000 equivalents in 2 h with 91–100% conversion. The obtained polyisoprenes feature high molecular weights (M n = 12.8 × 104–20.2 × 104) and moderate polydispersities (M w / M n = 2.7–3.6), however excellent control of regio- and stereoselectivities (up to 9.9% cis -1,4 units) was observed. [ABSTRACT FROM AUTHOR]

Neutralbis(alkyl)-organolanthanide complexes supported by tridentate{N–,N,N} monoanionic 5-methylthiazole- or benzothiazole-amidopyridinateligands have been prepared and completely characterized: (LThiaMe2)Ln(CH2SiMe3)2[Ln= Lu3+(3), Er3+(7), Yb3+(8)] and (LBnThMe2)Lu(CH2SiMe3)2(5). Similarly to related Y3+systems, the nature of thethiazole unit controls the ultimate catalyst stability in solution.In the diamagnetic Lu3+complex 5, a progressiveand complete rearrangement of its metal coordination sphere takesplace through a metal-to-ligand alkyl migration with subsequent benzothiazolering-opening and generation of the Lu3+mono(alkyl)-arylthiolatespecies stabilized by a tetradentate {N–,N,N,S–} dianionic ligand. On the other hand, the 5-methylthiazole-containingcomplexes 3, 7, and 8showedno evidence of any ligand rearrangement. Complexes 3–8have been tested as homogeneous catalysts in isoprene (IP)polymerization, after activation with selected organoborates. Binarysystems 3/TB and 7/TB [TB = tritylium tetrakis(pentafluorophenyl)borate]show the highest activity and living character toward IP polymerization,affording polymers with relatively high trans-1,4-selectivity(up to 76.4%), moderate molecular weights (Mnup to 146 000 g/mol), and narrow polydispersities(Mw/Mn). Dependingon the rare-earth ion of choice, a prevalent trans-1,4 (Lu3+, Er3+, Yb3+; up to 76.4%)or a dominant 3,4 (Y3+; 92.7%) polymer structure is observed.The influence of the ligand type, metal ion, and activator(s) on theultimate catalyst activity and selectivity is discussed. [ABSTRACT FROM AUTHOR]

Oxidation reactions of the Yb(II) hydride [{tBuC(NC6H3-2,6-iPr2)2}Yb(μ-H)]2(1) with CuCl(1:2 molarratio) and (PhCH2S)2(1:1 molar ratio) revealedthat the hydrido anion in 1is a stronger reductant thanthe Yb(II) cation. Both reactions occur with evolution of H2and afford the dimeric Yb(II) species [{tBuC(NC6H3-2,6-iPr2)2}Yb(μ-X)]2(X = Cl (2), SCH2Ph (3)) in which a κ1-amido,η6-arene type of coordination of amidinate ligand is retained.Reaction of 1with 2 equiv of (PhCH2S)2results in oxidation of both Yb(II) and hydrido centers andleads to the formation of the Yb(III) complex [{tBuC(NC6H3-2,6-iPr2)2}Yb(μ-SCH2Ph)2]2(4). Complex 4can be also synthesizedby oxidation of 3with an equimolar amount of (PhCH2S)2. It was demonstrated that oxidation of theytterbium center to the trivalent state leads to switching of thecoordination mode of amidinate ligand from κ1-amido,η6-arene to “classical” κ1,κ1-N,N-chelating. Unlike Yb(III) bis(alkyl)species supported by bulky amidopyridinate ligands, the reaction of[{tBuC(NC6H3-2,6-iPr2)2}Yb(CH2SiMe3)2(THF)] (6) with PhSiH3(1:2 molarratio) occurs with reduction of ytterbium to a divalent state andaffords 1. Thus, reduction of Yb(III) to Yb(II) leadsto a change of coordination mode from κ1,κ1-N,N to κ1-N, η6-arene.Oxidation of 1by 2,6-iPr2C6H3NC(H)C(H)NC6H3-2,6-iPr2was found to resultin oxidation of the hydrido ligand and ytterbium ion and formationof the mixed-valent ion-pair complex [{tBuC(NC6H3-2,6-iPr2)2}Yb(DME)2][{2,6-iPr2C6H3NC(H)C(H)NC6H3-2,6-iPr2}2Yb]−(5). The σ-bond metathesis reaction of 1with Ph2PH allowed for the synthesis of the firstmixed-ligand hydrido–phosphido Yb(II) species [{tBuC(NC6H3-2,6-iPr2)2}Yb(μ-H)(μ-PPh2)Yb{tBuC(NC6H3-2,6-iPr2)2}] (7). The second hydrido ligand cannotbe replaced by a phosphido ligand. [ABSTRACT FROM AUTHOR]

The reaction of cadmium amalgam with excess of 3,6-di- tert -butyl- o -quinone (3,6-Q) in THF afforded the new bis- o -semiquinonato cadmium(II) complex coordinated with one molecule of neutral o -quinone (3,6-SQ) 2 Cd(3,6-Q) ( 1 ) acting as a starting reagent to other bis- o -semiquinonato cadmium(II) complex with N-heterocyclic carbene (NHC)–(3,6-SQ) 2 Cd{C[N(Ar)(CH)] 2 } (Ar = 2,6-dimethylphenyl) ( 2 ). Both complexes possess a singlet ground state with thermally accessible triplet state (the singlet-triplet gap is 8 cm − 1 for 1 and 132 cm − 1 for 2 ) as confirmed by magnetic data. The antiferromagnetic exchange SQ–SQ is observed for both complexes. [ABSTRACT FROM AUTHOR]

Two new hypercoordinated tin(IV) complexes bearing 2-hydroxy-3,6-di- tert -butyl- p -benzoquinone (L 1 H) and 2-hydroxy-3,6-di- tert -butyl- N -phenyl- p -iminobenzoquinone (L 2 H) ligands were synthesized and investigated using IR-, UV–Vis, NMR spectroscopy and X-ray diffraction. The rare examples of octacoordinated tin compounds are realized by four bidentate ligands L 1 (in 1) or L 2 (in 2) bonded with metal center. Complexes are characterized by irregular bicapped trigonal prismatic distorted toward the idealized dodecahedron geometry of coordination polyhedron in crystals according to the X-ray diffraction. The dynamic transformation between bicapped trigonal prismatic and dodecahedron configurations of coordination polyhedra was found and investigated in solution of 1 and 2 by means of Variable Temperature NMR spectroscopy. Octacoordinated tin(IV) complexes bearing hydroxy- p -benzoquinone type ligands were synthesized and investigated. Complexes are characterized by distorted bicapped trigonal prismatic geometry in crystals. The dynamic process between bicapped trigonal prismatic and dodecahedron configurations of tin coordination sphere was studied in solution using VT NMR spectroscopy. Image 1 • Synthesis and structural investigations of hypercoordinated coordination compounds. • Bicapped trigonal prismatic SnIV complexes. • Dynamics of coordination sphere in solution. [ABSTRACT FROM AUTHOR]