Luminescent Er3+ based single molecule magnets with fluorinated alkoxide or aryloxide ligands.

We report the synthesis, structures, and magnetic and luminescence properties of a series of new mono- and 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.

π-Carbazolyl supported bis(alkyl) complexes of Sc, Y and La for α-olefin polymerization and hydrogenation.

A series of new half-sandwich bis(alkyl) rare-earth metal complexes coordinated by a sterically demanding 1,3,6,8-tetra-tert-butyl-carbazol-9-yl ligand [tBu4Carb]La(CH2C6H5)2(THF) (1-La), [tBu4Carb]Ln(o-NMe2C6H4CH2)2 (Ln = Sc (2-Sc), Y (2-Y), La (2-La), [tBu4Carb]Ln(CH2SiMe3)2(THF) (Ln = Sc (3-Sc), Y (3-Y)), were synthesized. 1-La, 2-La, and 2-Y were prepared by an alkane elimination protocol, while 2-Sc, 3-Sc, and 3-Y became accessible only when salt metathesis reactions of tBu4CarbK with R2Ln(THF)n+[BPh4]- were employed. X-ray analysis revealed that in all complexes the carbazolyl ligand exhibits π-coordination with metal ions. 2-Sc and 3-Sc when activated with [Ph3C][B(C6F5)4] demonstrate excellent activity in α-olefin (octene-1, nonene-1, decene-1 and 1,1-diphenyl-but-1-ene) polymerization. When H2 was used as a chain transfer agent (1 bar, rt) in the presence of 3-Sc/[Ph3C][B(C6F5)4] or 2-Y, 2-La olefin hydrogenation occurred with quantitative conversion.

Amine-boranes reactions promoted by lanthanide(II) ions.

The catalytic activity in amine-borane dehydrogenation is shown for the first time for Ln(II) species using complexes [{(p-tBu-C6H4)2CH}2M·L] (M = Yb, Sm, L = (DME)2, TMEDA). The protonation of M(II)-C bonds with HNR1R2BH3 affords amidoborane complexes [M(NR1R2BH3)2L], which under excess HNMe2BH3 transform to [NMe2BH2NMe2BH3]- derivatives, both serving as the dehydrocoupling intermediates.

Single-molecule magnet behavior in luminescent carbazolyl Dy(iii) octahedral complexes with a quasi linear N--Dy-N- angle.

We report the synthesis, photoluminescence and magnetic properties of two octahedral dysprosium complexes [DyR2(py)4][BPh4]·2py (1) and [DyR2(THF)4][BPh4] (2) (R = carbazolyl, py = pyridine, THF = tetrahydrofuran) exhibiting a quasi linear N-Dy-N angle in the axial direction, suitable for providing a coordination environment allowing the zero-field slow relaxation of magnetization.

Thermally Stable Ln(II) and Ca(II) Bis(benzhydryl) Complexes: Excellent Precatalysts for Intermolecular Hydrophosphination of C-C Multiple Bonds.

A series of Ln(II) and Ca(II) bis(alkyl) complexes with bulky benzhydryl ligands, [( p- tBu-C6H4)2CH]2M(L n) (M = Sm, L = DME, n = 2 (1); M = Sm, Yb, Ca, L = TMEDA, n = 1 (2, 3, 4), were synthesized by the salt-metathesis reaction of MI2(THF) n ( n = 0-2) and [( p- tBu-C6H4)2CH]-Na+. In complex 1, the benzhydryl ligands are bound to the metal center in η2-coordination mode. Unlike complex 1, in isomorphous complexes 3 and 4, due to the coordination unsaturation of the metal center, the both benzhydryl ligands coordinate to the metal in η3-fashion. In complex 2, one ligand is η3-coordinated while the second one is η4-coordinated to the Sm(II) ion. Complexes 2-4 demonstrated unprecedented thermal stability: no evidence of decomposition was observed after heating their solutions in C6D6 at 100 °C during 72 h. Complex 1 behaves differently: thermolysis in C6D6 solution at 75 °C results in total decomposition in 8 h. Addition of DME promotes decomposition of 2-4 and makes it feasible at 40 °C. Complexes 1-4 demonstrated high catalytic activity and excellent regio- and chemoselectivities in intermolecular hydrophosphination of double and triple C-C bonds with both primary and secondary phosphines. Complexes 2 and 3 enable addition of PhPH2 toward the internal C═C bond of Z- and E-stilbenes with 100% conversion under mild conditions. Double sequential hydrophosphination of phenylacetylene with Ph2PH and PhPH2 was realized due to the application of Yb(II) complex as a catalyst.

Single-molecule magnet behaviour in a Dy(iii) pentagonal bipyramidal complex with a quasi-linear Cl-Dy-Cl sequence.

We report the synthesis and magnetic investigation of a dysprosium pentagonal bipyramidal complex [Dy(THF)5Cl2][BPh4] (1) exhibiting a linear Cl-Dy-Cl sequence suitable for providing a coordination environment allowing a zero-field slow relaxation of the magnetization. Besides, the complex also shows dual luminescence originating from [BPh4]- and Dy3+.

Half-Sandwich Alkyl, Amido, and Iodo Samarium(II) Complexes: Non-Conventional Sterically Governed Oxidation of (tBu4 Carb)2 Sm.

The half-sandwich tetra-tert-butylcarbazol-9-yl iodo complex [(tBu4 Carb)Sm(µ-I)(THF)2 ]2 (1) was synthesized by the salt metathesis reaction of tBu4 CarbK and SmI2 (THF)2 in THF. Complex 1 along with metallic Cu was also isolated from the oxidation reaction of (tBu4 Carb)2 Sm by CuI. The formation of stable radical tBu4 Carb. was detected in this non-conventional process, indicating preferential oxidation of anion tBu4 Carb- vs. SmII . The treatment of 1 with two equivalents of dibenzo-18-crown-6 resulted in heterolytic dissociation of a η5 -bond Sm-tBu4 Carb and afforded an ionic compound [tBu4 carb- ][SmI(crown)(THF)2 ]+ (4). Alkylation of 1 with o-NMe2 C6 H4 CH2 K (1:2 molar ratio) in THF allowed for the synthesis of half-sandwich SmII alkyl complex (tBu4 Carb)SmCH2 (o-NMe2 C6 H4 CH2 )(THF)2 (5) in 55 % yield. The amido complex (tBu4 Carb)SmN(SiMe3 )2 (DME) (6) was obtained by the reaction of 1 with two molar equivalents of NaN(SiMe3 )2 in THF in 89 % yield.

Divalent heteroleptic ytterbium complexes--effective catalysts for intermolecular styrene hydrophosphination and hydroamination.

New heteroleptic Yb(II)-amide species supported by amidinate and 1,3,6,8-tetra-tert-butylcarbazol-9-yl ligands [2-MeOC6H4NC(tBu)N(C6H3-iPr2-2,6)]YbN(SiMe3)2(THF) (6) and [1,3,6,8-tBu4C12H4N]Yb[N(SiMe3)2](THF)n (n = 1 (7), 2 (8)) were synthesized using the amine elimination approach. Complex 6 features an unusual κ(1)-N,κ(2)-O,η(6)-arene coordination mode of the amidinate ligand onto Yb(II). Complexes 7 and 8 represent the first examples of lanthanide complexes with π-coordination of carbazol-9-yl ligands. Complexes 6 and 7, as well as the amidinate-Yb(II)-amide [tBuC(NC6H3-iPr2-2,6)2]YbN(SiMe3)2(THF) (5), are efficient precatalysts for the intermolecular hydrophosphination and hydroamination of styrene with diphenylphosphine, phenylphosphine, and pyrrolidine to give exclusively the anti-Markovnikov monoaddition product. For both types of reaction, the best performances were observed with carbazol-9-yl complex 7 (TONs up to 92 and 48 mol/mol at 60 °C, respectively).