Solid-State Structure and Solution Behavior of Eight-Coordinate Sm(III) Poly(pyrazolyl)borate Compounds

Abstract

[Sm(Tp(Me2)(2)(kappa(2)-S(2)CNR(2))] compounds (R = Et (1), Me (2); Tp(Me2) = HB(3,5-Me2pz)(3)) have been isolated from reaction of (R(2)NC(S)S)(2) with 2 equiv of [Sm(Tp(Me2)(2)]. Reductive cleavage of 2,2'-dipyridyl disulfide or 2,2'-dipyridyl diselenide by [Sm(Tp(Me2)(2)] afforded good yields of [Sm(Tp(Me2)(2)(kappa(2)-Y)] compounds (Y = 2-SC(5)H(4)N (3), 2-SeC(5)H(4)N (4)). 4 is the first selenopyridine complex of an f-block element. Sm(Tp(Me2)(2)(2-OC(5)H(4)N) (5) has been synthesized by salt metathesis of [Sm(Tp(Me2)(2)Cl] with the sodium salt of the 2-hydroxypyridine. The solid-state structures of 1, 3, 4, and 5 were determined by single-crystal X-ray diffraction analysis and revealed that the compounds are all eight-coordinate with dodecahedral geometry. The samarium atoms are bound in tridentate fashion to two pyrazolylborate ligands and in bidentate fashion by the third ligand. The solution behavior of the compounds was studied by (1)H NMR techniques. (1)H-(1)H exchange spectroscopy experiments give evidence for two distinct dynamic regimes occurring in solution.

Coordination of 2,2‘-Bipyridyl and 1,10-Phenanthroline to Yttrium and Lanthanum Complexes Based on a Scorpionate Ligand

“…Thus, the observed spectrum is consistent with a C 2 -symmetric structure and similar to those observed for [Sm(Tp Me2 ) 2 (X−X)] complexes, where X−X is a symmetrical bidentate ligand.…”

“…Polytopal analysis suggests that the metal coordination geometry is best described as being dodecahedral . This coordination geometry has been found already in other [Sm(Tp Me2 ) 2 (X−X)] compounds. , The intersecting trapezoids (defined by the atoms N12, N2, N1, N62 and N22, N32, N42, N52) make a dihedral angle of 82° rather than the ideal 90°. The trapezoids are almost planar, with normalized φ angles of 0.6° and 2.2°.…”

Uranium (III) Scorpionates: Synthesis and Structure of [(TpMe2)2U{N(C6H5)2}] and [(TpMe2)2U{N(SiMe3)2}]

“…2 However, in the past few years there has been increased interest in other alternative ligand systems, 3 including the polypyrazolyl borate or "scorpionate" ligands, a sobriquet coined by Trofimenko to relate the tridentate coordination behavior of these ligands to the simple analogy of a scorpion grabbing its prey with two claws and completing the attack with its stingerterminated overarching tail. 4 For the past few years we and Sella had investigated the chemistry of samarium and neodymium systems anchored by the hydrotris(3,5-dimethylpyrazolyl)borate scorpionate ligand, (Tp Me 2 ) -, and we have reported the synthesis of a variety of compounds, such as the halides [(Tp Me 2 ) 2 SmX] (X ) F, Cl, Br, I), 5 aryloxides [(Tp Me 2 ) 2 SmOR] (R ) Ph, Ph-4-Bu t , C 6 H 2 -2,4,6-Me 3 , C 5 H 4 N), [6][7][8] diphenylamide [(Tp Me 2 ) 2 -Sm(NPh 2 )], 7 phenylalkynide [(Tp Me 2 ) 2 Sm(CCPh)], 9 cyclopentadienide [(Tp Me 2 ) 2 Sm(Cp)], 10 and related neodymium complexes. 11 With the availability of [(Tp Me 2 ) 2 UI], 12 we decided to explore the chemistry of this system to assess whether it could be a useful precursor for a range of trivalent uranium [(Tp Me 2 ) 2 U(ER)] compounds and, if so, to compare their nature to the [(C 5 Me 5 ) 2 U(ER)] analogues.…”

“…For the past few years we and Sella had investigated the chemistry of samarium and neodymium systems anchored by the hydrotris(3,5-dimethylpyrazolyl)borate scorpionate ligand, (Tp Me 2 ) - , and we have reported the synthesis of a variety of compounds, such as the halides [(Tp Me 2 ) 2 SmX] (X = F, Cl, Br, I), aryloxides [(Tp Me 2 ) 2 SmOR] (R = Ph, Ph-4-Bu t , C 6 H 2 -2,4,6-Me 3 , C 5 H 4 N), − diphenylamide [(Tp Me 2 ) 2 Sm(NPh 2 )], phenylalkynide [(Tp Me 2 ) 2 Sm(CCPh)], cyclopentadienide [(Tp Me 2 ) 2 Sm(Cp)], and related neodymium complexes …”

Synthesis of Novel Binuclear Samarium Thiolate Complexes [(THF)3I2Sm(μ‐SAr)]2 (Ar=Ph, 4‐Me2NC6H4) and Crystal Structure of [(THF) 3I2Sm(μ‐S‐4‐Me2NC6H4)]2

“…5 However, another approach, the formation of Ln(III) thiolates from oxidation reactions of lanthanide(II) complexes with organic oxidants, has been less explored, and thus only a limited number of examples have been reported so far. For example, two mononuclear lanthanide thiolates (Me 5 C 5 ) 2 Sm(S-2,4,6-Me 3 C 6 -H 2 )(THF) 6 and Sm(TpMe 2 ) 2 (SC 5 H 4 N) (TpMe 2 ＝hydrotris(3,5-dimethylpyrazolyl)borate) 7 were obtained by oxidation reactions of the divalent (Me 5 C 5 ) 2 Ln or (Tp-Me 2 ) 2 Ln complexes with RSSR (R ＝ 2,4,6-Me 3 C 6 H 2 and C 5 H 4 N). Another Sm(III) thiolate [Li(TMEDA)] 3 -[Sm(SBut) 6 ] (TMEDA＝N,N,N',N'-tetramethylethylenediamine) was prepared from reactions of SmI 2 (THF) x with LiSBut, in which C-S bond was cleaved during the reaction and thus Sm(II) was oxidized to Sm(III).…”