σ-Donor versus η6-π-Arene Interactions in Monomeric Europium(II) and Ytterbium(II) Thiolates − An Experimental and Computational Study

Abstract

Keywords: Ab initio calculations / Lanthanides / π interactions / S ligands / YtterbiumThe base-free, hydrocarbon-soluble complexes M(SAr*) 2 (4a: M = Eu, orange; 4b: M = Yb, purple; Ar* = 2,6-Trip 2 C 6 H 3 ; Trip = 2,4,6-iPr 3 C 6 H 2 ) have been prepared by a protolysis reaction of the Grignard-analogous compound RLnI (R = 2-F 3 CC 6 H 4 ) with HSAr*. Compound 4b has been characterized by melting point, elemental analysis, 1 H, 13 C, and 171 Yb NMR, IR spectroscopy, UV/Vis spectrophotometry, mass spectrometry, and X-ray crystallography. Additionally, the purple Yb III complex YbI 2 (SAr*)(THF) 3 (3) and the yellow DME adduct Yb(SAr*) 2 (dme) 2 (5) have been synthesized and characterized by X-ray crystallography. The solid-state structures of 4a and 4b (as THF or benzene hemisolvates) show monomeric units with the metal atom bonded to two terminal

Stabilization of Unsolvated Europium and Ytterbium Pentafluorophenyls by π-Bonding Encapsulation through a Sterically Crowded Triazenido Ligand

“…This observation can be interpreted in terms of a hindered rotation around the N1−C1 bond and therefore the persistence of the metal−π-arene interactions in solution. A similar behavior with a rotational barrier of 54.3 kJ mol -1 was recently observed and confirmed by quantum-chemical calculations for the unsolvated ytterbium thiophenolate [Yb(S-2,6-Trip 2 C 6 H 3 ) 2 ] …”

Stabilization of Unsolvated Europium and Ytterbium Pentafluorophenyls by π-Bonding Encapsulation through a Sterically Crowded Triazenido Ligand

“…This observation can be interpreted in terms of a hindered rotation around the N1−C1 bond and therefore the persistence of the metal−π-arene interactions in solution. A similar behavior with a rotational barrier of 54.3 kJ mol -1 was recently observed and confirmed by quantum-chemical calculations for the unsolvated ytterbium thiophenolate [Yb(S-2,6-Trip 2 C 6 H 3 ) 2 ] …”

A Comparative Study of π-Arene-Bridged Lanthanum Arylamide and Aryloxide Dimers. Solution Behavior, Exchange Mechanisms, and X-ray Crystal Structures of La2(NH-2,6-iPr2C6H3)6, La(NH-2,6-iPr2C6H3)3(THF)3, and La(NH-2,6-iPr2C6H3)3(py)2

“…This lower energy feature is absent in all monomeric Lewis base adducts (Table ). Similar frequencies were also identified for η 6 -arene coordination of Ln(SAr*) 2 (Ln = Eu, Yb; Ar* = 2,6-Trip 2 C 6 H 3 ; Trip = 2,4,6- i Pr 3 C 6 H 2 ) 5 Infrared Vibrational Frequencies (cm -1 ) for the ν(CC) Stretch in 2,6-Diisopropylphenoxide and 2,6-Diisopropylanilide Complexes compoundν(CC)mediumrefArylamides La 2 (NHAr) 6 1587 1575 Nujol this work La 2 (NHAr) 6 1588 1572 benzene this work Sm 2 (NHAr) 6 1590 1575 Nujol 25 Sm 2 (NHAr) 6 1590 1572 benzene 25 La(NHAr) 3 (THF) 3 1588 Nujol this work La(NHAr) 3 (py) 2 1588 Nujol this work KNHAr 1581 Nujol this work H 2 NAr 1588 neat this workAryloxides La 2 (OAr) 6 1588 1571 Nujol 27 La 2 (OAr) 6 1588 1572 benzene 27 Nd 2 (OAr) 6 1588 1571 Nujol 6 Nd 2 (OAr) 6 1590 1572 benzene 6 Sm 2 (OAr) 6 1586 1572 Nujol 6 Sm 2 (OAr) 6 1589 1572 benzene 6 Er 2 (OAr) 6 1590 1571 Nujol 6 Er 2 (OAr) 6 1589 1572 benzene 6 U 2 (OAr) 6 1588 1553 Nujol 29 La(OAr) 3 (THF) 2 1587 Nujol 27 Pr(OAr) 3 (THF) 2 1584 Nujol 6 Nd(OAr) 3 (THF) 2 1585 Nujol 6 Sm(OAr) 3 (THF) 2 1585 Nujol 6 Gd(OAr) 3 (THF) 2 1585 Nujol 6 …”

Experimental and Theoretical Evidence for the First Example of an Organolanthanide(II) Compound Having an Indenyl Ligand Bonded to the Metal through the Benzo Ring in η4 Hapticity

“…The Yb−C(C 6 ring) bond distances range from 2.733(6) to 3.221(6) Å, and the corresponding Yb−C(37) and Yb−C(38) distances of 3.221(6) and 3.139(6) Å are significantly longer than the other Yb−C(C 6 ring) distances. The Yb−C(39) and Yb−C(42) distances of 2.903(6) and 3.010(7) Å (with an average of 2.956(7) Å) found in 1 are comparable to the average Yb−C distance of 2.973(9) Å found in Yb II (SAr*) 2 (Ar* = 2,6-Trip 2 C 6 H 3 with Trip = 2,4,6- i Pr 3 C 6 H 2 ) with Yb−arene π-bonding . They are also comparable to the Yb−C distances of 3.070(5)−3.421(6) Å associated with η 4 bonding in [Dmp(Tph)-N 3 YbC 6 F 5 ] (Dmp = 2,6-Mes 2 C 6 H 3 with Mes = 2,4,6-Me 3 C 6 H 2 ; Tph = 2-TripC 6 H 4 with Trip = 2,4,6- i Pr 3 C 6 H 2 ) .…”

Stabilization of Unsolvated Europium and Ytterbium Pentafluorophenyls by π-Bonding Encapsulation through a Sterically Crowded Triazenido Ligand

“…This observation can be interpreted in terms of a hindered rotation around the N1−C1 bond and therefore the persistence of the metal−π-arene interactions in solution. A similar behavior with a rotational barrier of 54.3 kJ mol -1 was recently observed and confirmed by quantum-chemical calculations for the unsolvated ytterbium thiophenolate [Yb(S-2,6-Trip 2 C 6 H 3 ) 2 ] …”

A Comparative Study of π-Arene-Bridged Lanthanum Arylamide and Aryloxide Dimers. Solution Behavior, Exchange Mechanisms, and X-ray Crystal Structures of La2(NH-2,6-iPr2C6H3)6, La(NH-2,6-iPr2C6H3)3(THF)3, and La(NH-2,6-iPr2C6H3)3(py)2

“…This lower energy feature is absent in all monomeric Lewis base adducts (Table ). Similar frequencies were also identified for η 6 -arene coordination of Ln(SAr*) 2 (Ln = Eu, Yb; Ar* = 2,6-Trip 2 C 6 H 3 ; Trip = 2,4,6- i Pr 3 C 6 H 2 ) 5 Infrared Vibrational Frequencies (cm -1 ) for the ν(CC) Stretch in 2,6-Diisopropylphenoxide and 2,6-Diisopropylanilide Complexes compoundν(CC)mediumrefArylamides La 2 (NHAr) 6 1587 1575 Nujol this work La 2 (NHAr) 6 1588 1572 benzene this work Sm 2 (NHAr) 6 1590 1575 Nujol 25 Sm 2 (NHAr) 6 1590 1572 benzene 25 La(NHAr) 3 (THF) 3 1588 Nujol this work La(NHAr) 3 (py) 2 1588 Nujol this work KNHAr 1581 Nujol this work H 2 NAr 1588 neat this workAryloxides La 2 (OAr) 6 1588 1571 Nujol 27 La 2 (OAr) 6 1588 1572 benzene 27 Nd 2 (OAr) 6 1588 1571 Nujol 6 Nd 2 (OAr) 6 1590 1572 benzene 6 Sm 2 (OAr) 6 1586 1572 Nujol 6 Sm 2 (OAr) 6 1589 1572 benzene 6 Er 2 (OAr) 6 1590 1571 Nujol 6 Er 2 (OAr) 6 1589 1572 benzene 6 U 2 (OAr) 6 1588 1553 Nujol 29 La(OAr) 3 (THF) 2 1587 Nujol 27 Pr(OAr) 3 (THF) 2 1584 Nujol 6 Nd(OAr) 3 (THF) 2 1585 Nujol 6 Sm(OAr) 3 (THF) 2 1585 Nujol 6 Gd(OAr) 3 (THF) 2 1585 Nujol 6 …”

Experimental and Theoretical Evidence for the First Example of an Organolanthanide(II) Compound Having an Indenyl Ligand Bonded to the Metal through the Benzo Ring in η4 Hapticity

“…The Yb−C(C 6 ring) bond distances range from 2.733(6) to 3.221(6) Å, and the corresponding Yb−C(37) and Yb−C(38) distances of 3.221(6) and 3.139(6) Å are significantly longer than the other Yb−C(C 6 ring) distances. The Yb−C(39) and Yb−C(42) distances of 2.903(6) and 3.010(7) Å (with an average of 2.956(7) Å) found in 1 are comparable to the average Yb−C distance of 2.973(9) Å found in Yb II (SAr*) 2 (Ar* = 2,6-Trip 2 C 6 H 3 with Trip = 2,4,6- i Pr 3 C 6 H 2 ) with Yb−arene π-bonding . They are also comparable to the Yb−C distances of 3.070(5)−3.421(6) Å associated with η 4 bonding in [Dmp(Tph)-N 3 YbC 6 F 5 ] (Dmp = 2,6-Mes 2 C 6 H 3 with Mes = 2,4,6-Me 3 C 6 H 2 ; Tph = 2-TripC 6 H 4 with Trip = 2,4,6- i Pr 3 C 6 H 2 ) .…”

Stabilization of Unsolvated Europium and Ytterbium Pentafluorophenyls by π-Bonding Encapsulation through a Sterically Crowded Triazenido Ligand

“…This observation can be interpreted in terms of a hindered rotation around the N1−C1 bond and therefore the persistence of the metal−π-arene interactions in solution. A similar behavior with a rotational barrier of 54.3 kJ mol -1 was recently observed and confirmed by quantum-chemical calculations for the unsolvated ytterbium thiophenolate [Yb(S-2,6-Trip 2 C 6 H 3 ) 2 ] …”

A Comparative Study of π-Arene-Bridged Lanthanum Arylamide and Aryloxide Dimers. Solution Behavior, Exchange Mechanisms, and X-ray Crystal Structures of La2(NH-2,6-iPr2C6H3)6, La(NH-2,6-iPr2C6H3)3(THF)3, and La(NH-2,6-iPr2C6H3)3(py)2

“…This lower energy feature is absent in all monomeric Lewis base adducts (Table ). Similar frequencies were also identified for η 6 -arene coordination of Ln(SAr*) 2 (Ln = Eu, Yb; Ar* = 2,6-Trip 2 C 6 H 3 ; Trip = 2,4,6- i Pr 3 C 6 H 2 ) 5 Infrared Vibrational Frequencies (cm -1 ) for the ν(CC) Stretch in 2,6-Diisopropylphenoxide and 2,6-Diisopropylanilide Complexes compoundν(CC)mediumrefArylamides La 2 (NHAr) 6 1587 1575 Nujol this work La 2 (NHAr) 6 1588 1572 benzene this work Sm 2 (NHAr) 6 1590 1575 Nujol 25 Sm 2 (NHAr) 6 1590 1572 benzene 25 La(NHAr) 3 (THF) 3 1588 Nujol this work La(NHAr) 3 (py) 2 1588 Nujol this work KNHAr 1581 Nujol this work H 2 NAr 1588 neat this workAryloxides La 2 (OAr) 6 1588 1571 Nujol 27 La 2 (OAr) 6 1588 1572 benzene 27 Nd 2 (OAr) 6 1588 1571 Nujol 6 Nd 2 (OAr) 6 1590 1572 benzene 6 Sm 2 (OAr) 6 1586 1572 Nujol 6 Sm 2 (OAr) 6 1589 1572 benzene 6 Er 2 (OAr) 6 1590 1571 Nujol 6 Er 2 (OAr) 6 1589 1572 benzene 6 U 2 (OAr) 6 1588 1553 Nujol 29 La(OAr) 3 (THF) 2 1587 Nujol 27 Pr(OAr) 3 (THF) 2 1584 Nujol 6 Nd(OAr) 3 (THF) 2 1585 Nujol 6 Sm(OAr) 3 (THF) 2 1585 Nujol 6 Gd(OAr) 3 (THF) 2 1585 Nujol 6 …”

Experimental and Theoretical Evidence for the First Example of an Organolanthanide(II) Compound Having an Indenyl Ligand Bonded to the Metal through the Benzo Ring in η4 Hapticity

“…The Yb−C(C 6 ring) bond distances range from 2.733(6) to 3.221(6) Å, and the corresponding Yb−C(37) and Yb−C(38) distances of 3.221(6) and 3.139(6) Å are significantly longer than the other Yb−C(C 6 ring) distances. The Yb−C(39) and Yb−C(42) distances of 2.903(6) and 3.010(7) Å (with an average of 2.956(7) Å) found in 1 are comparable to the average Yb−C distance of 2.973(9) Å found in Yb II (SAr*) 2 (Ar* = 2,6-Trip 2 C 6 H 3 with Trip = 2,4,6- i Pr 3 C 6 H 2 ) with Yb−arene π-bonding . They are also comparable to the Yb−C distances of 3.070(5)−3.421(6) Å associated with η 4 bonding in [Dmp(Tph)-N 3 YbC 6 F 5 ] (Dmp = 2,6-Mes 2 C 6 H 3 with Mes = 2,4,6-Me 3 C 6 H 2 ; Tph = 2-TripC 6 H 4 with Trip = 2,4,6- i Pr 3 C 6 H 2 ) .…”