Isolation and electronic structures of lanthanide(II) bis(trimethylsilyl)phosphide complexes

Jack Baldwin; Adam Brookfield; George Whitehead; Louise Natrajan; Eric Mcinnes; Meagan Oakley; David Mills

doi:10.1021/acs.inorgchem.4c02888

Isolation and electronic structures of lanthanide(II) bis(trimethylsilyl)phosphide complexes

Jack Baldwin, Adam Brookfield, George Whitehead, Louise Natrajan, Eric Mcinnes, Meagan Oakley, David Mills

Research output: Contribution to journal › Article › peer-review

Abstract

Whilst lanthanide (Ln) silylamide chemistry is mature, the corresponding silylphosphide chemistry is underdeveloped, with [Sm{P(SiMe₃)₂}{μ-P(SiMe₃)₂}₃Sm(THF)₃] being the sole example of a structurally authenticated Ln(II) silylphosphide complex. Here we expand Ln(II) {P(SiMe₃)₂} chemistry through the synthesis and characterization of nine complexes. The dinuclear ‘ate’ salt-occluded complexes [{Ln[P(SiMe₃)₂]₃(THF)}₂(μ-I)K₃(THF)] (1-Ln; Ln = Sm, Eu) and polymeric ‘ate’ complex [KYb{P(SiMe₃)₂}₃{μ-K[P(SiMe₃)₂]}₂]∞(2-Yb) were prepared by the respective salt metathesis reactions of parent [LnI₂(THF)₂] (Ln = Sm, Eu, Yb) with 2 or 3 eq. of K{P(SiMe3)2} in diethyl ether. The separate treatment of these complexes with either pyridine or 18-crown-6 led to the formation of the mononuclear solvated adducts, trans-[Ln{P(SiMe₃)₂}₂(py)₄] (3-Ln; Ln = Sm, Eu, Yb) and [Ln{P(SiMe₃)₂}₂(18-crown-6)] (4-Ln; Ln = Sm, Eu, Yb), with concomitant loss of K{P(SiMe₃)₂}. The complexes were characterized by a combination of NMR, EPR, ATR-IR, electronic absorption and emission spectroscopies, elemental
analysis, SQUID magnetometry, and single crystal X-ray diffraction. We find that these complexes contrast with those of related Ln(II) bis(silyl)amide complexes due to differences in ligand donor atom hardness and ligand steric requirements from Ln–P bonds being longer than Ln–N bonds. This leads to higher coordination numbers, shorter luminescence lifetimes, and smaller easy-axis magnetic anisotropy parameters.

Original language	English
Pages (from-to)	18120–18136
Journal	Inorganic Chemistry
Volume	63
Issue number	39
DOIs	https://doi.org/10.1021/acs.inorgchem.4c02888
Publication status	Published - 16 Sept 2024

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EPSRC National Research Facility for Electron Paramagnetic Resonance
Collison, D. (Academic lead), Mcinnes, E. (Academic lead), Tuna, F. (Academic lead), Bowen, A. (Academic lead), Shanmugam, M. (Senior Technical Specialist), Brookfield, A. (Technical Specialist), Fleming, E. (Other) & Cliff, M. (Platform Lead)
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@article{f4223073fde945c2b247bb413534d828,

title = "Isolation and electronic structures of lanthanide(II) bis(trimethylsilyl)phosphide complexes",

abstract = "Whilst lanthanide (Ln) silylamide chemistry is mature, the corresponding silylphosphide chemistry is underdeveloped, with [Sm{P(SiMe3)2}{μ-P(SiMe3)2}3Sm(THF)3] being the sole example of a structurally authenticated Ln(II) silylphosphide complex. Here we expand Ln(II) {P(SiMe3)2} chemistry through the synthesis and characterization of nine complexes. The dinuclear {\textquoteleft}ate{\textquoteright} salt-occluded complexes [{Ln[P(SiMe3)2]3(THF)}2(μ-I)K3(THF)] (1-Ln; Ln = Sm, Eu) and polymeric {\textquoteleft}ate{\textquoteright} complex [KYb{P(SiMe3)2}3{μ-K[P(SiMe3)2]}2]∞(2-Yb) were prepared by the respective salt metathesis reactions of parent [LnI2(THF)2] (Ln = Sm, Eu, Yb) with 2 or 3 eq. of K{P(SiMe3)2} in diethyl ether. The separate treatment of these complexes with either pyridine or 18-crown-6 led to the formation of the mononuclear solvated adducts, trans-[Ln{P(SiMe3)2}2(py)4] (3-Ln; Ln = Sm, Eu, Yb) and [Ln{P(SiMe3)2}2(18-crown-6)] (4-Ln; Ln = Sm, Eu, Yb), with concomitant loss of K{P(SiMe3)2}. The complexes were characterized by a combination of NMR, EPR, ATR-IR, electronic absorption and emission spectroscopies, elemental analysis, SQUID magnetometry, and single crystal X-ray diffraction. We find that these complexes contrast with those of related Ln(II) bis(silyl)amide complexes due to differences in ligand donor atom hardness and ligand steric requirements from Ln–P bonds being longer than Ln–N bonds. This leads to higher coordination numbers, shorter luminescence lifetimes, and smaller easy-axis magnetic anisotropy parameters.",

author = "Jack Baldwin and Adam Brookfield and George Whitehead and Louise Natrajan and Eric Mcinnes and Meagan Oakley and David Mills",

year = "2024",

month = sep,

day = "16",

doi = "10.1021/acs.inorgchem.4c02888",

language = "English",

volume = "63",

pages = "18120–18136",

journal = "Inorganic Chemistry",

issn = "0020-1669",

publisher = "American Chemical Society",

number = "39",

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TY - JOUR

T1 - Isolation and electronic structures of lanthanide(II) bis(trimethylsilyl)phosphide complexes

AU - Baldwin, Jack

AU - Brookfield, Adam

AU - Whitehead, George

AU - Natrajan, Louise

AU - Mcinnes, Eric

AU - Oakley, Meagan

AU - Mills, David

PY - 2024/9/16

Y1 - 2024/9/16

N2 - Whilst lanthanide (Ln) silylamide chemistry is mature, the corresponding silylphosphide chemistry is underdeveloped, with [Sm{P(SiMe3)2}{μ-P(SiMe3)2}3Sm(THF)3] being the sole example of a structurally authenticated Ln(II) silylphosphide complex. Here we expand Ln(II) {P(SiMe3)2} chemistry through the synthesis and characterization of nine complexes. The dinuclear ‘ate’ salt-occluded complexes [{Ln[P(SiMe3)2]3(THF)}2(μ-I)K3(THF)] (1-Ln; Ln = Sm, Eu) and polymeric ‘ate’ complex [KYb{P(SiMe3)2}3{μ-K[P(SiMe3)2]}2]∞(2-Yb) were prepared by the respective salt metathesis reactions of parent [LnI2(THF)2] (Ln = Sm, Eu, Yb) with 2 or 3 eq. of K{P(SiMe3)2} in diethyl ether. The separate treatment of these complexes with either pyridine or 18-crown-6 led to the formation of the mononuclear solvated adducts, trans-[Ln{P(SiMe3)2}2(py)4] (3-Ln; Ln = Sm, Eu, Yb) and [Ln{P(SiMe3)2}2(18-crown-6)] (4-Ln; Ln = Sm, Eu, Yb), with concomitant loss of K{P(SiMe3)2}. The complexes were characterized by a combination of NMR, EPR, ATR-IR, electronic absorption and emission spectroscopies, elemental analysis, SQUID magnetometry, and single crystal X-ray diffraction. We find that these complexes contrast with those of related Ln(II) bis(silyl)amide complexes due to differences in ligand donor atom hardness and ligand steric requirements from Ln–P bonds being longer than Ln–N bonds. This leads to higher coordination numbers, shorter luminescence lifetimes, and smaller easy-axis magnetic anisotropy parameters.

AB - Whilst lanthanide (Ln) silylamide chemistry is mature, the corresponding silylphosphide chemistry is underdeveloped, with [Sm{P(SiMe3)2}{μ-P(SiMe3)2}3Sm(THF)3] being the sole example of a structurally authenticated Ln(II) silylphosphide complex. Here we expand Ln(II) {P(SiMe3)2} chemistry through the synthesis and characterization of nine complexes. The dinuclear ‘ate’ salt-occluded complexes [{Ln[P(SiMe3)2]3(THF)}2(μ-I)K3(THF)] (1-Ln; Ln = Sm, Eu) and polymeric ‘ate’ complex [KYb{P(SiMe3)2}3{μ-K[P(SiMe3)2]}2]∞(2-Yb) were prepared by the respective salt metathesis reactions of parent [LnI2(THF)2] (Ln = Sm, Eu, Yb) with 2 or 3 eq. of K{P(SiMe3)2} in diethyl ether. The separate treatment of these complexes with either pyridine or 18-crown-6 led to the formation of the mononuclear solvated adducts, trans-[Ln{P(SiMe3)2}2(py)4] (3-Ln; Ln = Sm, Eu, Yb) and [Ln{P(SiMe3)2}2(18-crown-6)] (4-Ln; Ln = Sm, Eu, Yb), with concomitant loss of K{P(SiMe3)2}. The complexes were characterized by a combination of NMR, EPR, ATR-IR, electronic absorption and emission spectroscopies, elemental analysis, SQUID magnetometry, and single crystal X-ray diffraction. We find that these complexes contrast with those of related Ln(II) bis(silyl)amide complexes due to differences in ligand donor atom hardness and ligand steric requirements from Ln–P bonds being longer than Ln–N bonds. This leads to higher coordination numbers, shorter luminescence lifetimes, and smaller easy-axis magnetic anisotropy parameters.

U2 - 10.1021/acs.inorgchem.4c02888

DO - 10.1021/acs.inorgchem.4c02888

M3 - Article

SN - 0020-1669

VL - 63

SP - 18120

EP - 18136

JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 39

ER -

Isolation and electronic structures of lanthanide(II) bis(trimethylsilyl)phosphide complexes

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