Ammoniacal Synthesis of Lanthanum Aryloxide Complexes and Observation of a Unique Interconversion between Oxygen- and .eta.-Arene-Bridged Dimeric Species. X-ray Crystal Structures of La2(OAr)6(NH3)n (n = 0, 2), La(OAr)3(NH3)4, and La(OAr)3(THF)2 (Ar = 2,6-i-Pr2C6H3)

The Synthesis, Structures and Polymorphism of the Dimeric Trivalent Rare‐Earth 3,5‐Dimethylpyrazolate Complexes [Ln(Me2pz)3(thf)]2

“…However, because the η 2 ‐binding of the μ‐η 2 :η 5 ‐Ph 2 pz ligands of this trinuclear complex is highly unsymmetrical, a comparison with the symmetrical μ‐η 2 ‐Me 2 pz‐Ce interactions of 2a is less appropriate, although the bonding appears stronger in 2a . For the η 5 ‐Me 2 pz‐Ce ligation, the observed Ce–C bond lengths [2.953(3)–3.080(3) Å] correspond well with the Ln–C distances in six‐coordinate [Ln{OC 6 H 3 ( i Pr)‐2,6‐μ‐(O,η 6 ‐Ar)‐O‐C 6 H 3 ( i Pr)‐2,6}] 2 {Ln = La 2.978(10)–3.164(9) Å; Ln = Nd 2.898(12)–3.183(1) Å17} (Nd 3+ 0.04 Å smaller than Ce 3+ ),16 and the La–C distances in nine‐coordinate [La(η 6 ‐ArH)(AlCl 4 ) 3 ] (Ar‐H = C 6 Me 6 or PhMe) [2.927(7)–3.035(7) Å] 18. In addition, they are similar to the Nd–C distances of the η 5 (pz)‐Nd interaction of [Nd 3 (pz) 9 (pzH) 2 ] [2.882(3)–3.030(3) Å],5e and to the Ce–C bond lengths of the η 6 ‐Ar–Ce coordination in seven‐coordinate [Ce(OC 6 H 3 Ph 2 ‐2,6) 3 ] [2.975(3)–3.167(3) Å] 19…”

Mono-cyclopentadienyl complexes of lanthanum: synthesis and characterization of anilido derivatives

“…The La-O(THF) distances do not differ greatly from those observed in La(O-2,6-i Pr 2 C 6 H 3 ) 3 (THF) 2 (2.52(1) A ave) [36] as well as other THF adducts of La such as La(g 5 -C 5 Me 5 )[CH(SiMe 3 ) 2 ] 2 (THF) (2.547 (6) A) [37], La(g 5 -C 5 H 5 ) 3 (THF) (2.57(1) A) [38], (g 5 :g 1 :g 1 -C 5 -H 3 (CH 2 -CH 2 NMe 2 ) 2 -1,2)LaI 2 (THF) (2.558(3) A) [20] and (g 5 :g 1 :g 1 -C 5 H 3 (CH 2 CH 2 NMe 2 ) 2 -1,3)LaI 2 (THF) (2.593 (3) A) [20]. The distances between the metal center and the carbon atoms of the Cp ring are within the expected range for such compounds.…”

Elusive Trimethyllanthanum: Snapshots of Extensive Methyl Group Degradation in LaAl Heterobimetallic Complexes

“…[36] The La À CA C H T U N G T R E N N U N G (arene) distances range from 3.136(9) to 3.180(9) , matching those in [La 2 (OC 6 H 3 -2,6-iPr 2 ) 6 ] (2.978(10)-3.164(9) ). [37] The tetradecametallic complex [La 5 Al 9 (CH) 6 …”