Cationic and Neutral Heterometallic Ir-Group 12 Element Polyhydride Compounds: Synthesis, Structure and Reactivity

Amber M. Walsh; Carlos Martín-Fernández; John P. Lowe; Stuart A. Macgregor; Mary F. Mahon; Michael K. Whittlesey

doi:10.1021/acs.inorgchem.5c04368

Cationic and Neutral Heterometallic Ir-Group 12 Element Polyhydride Compounds: Synthesis, Structure and Reactivity

Amber M. Walsh, Carlos Martín-Fernández, John P. Lowe, Stuart A. Macgregor, Mary F. Mahon, Michael K. Whittlesey

University of St Andrews

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

Abstract

The preparation and reactivity of some Ir–Zn and Ir–Cd heterometallic hydride complexes are described. Treatment of [Ir(IPr)₂H₂][BAr^F₄] (1; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; Ar^F = 3,5-C₆H₃(CF₃)₂) with M′R₂ (M′ = Zn; R = Ph, Me, Et; M′ = Cd, R = Me) and Me₃SiCH=CH₂ results in dehydrogenation of an IPr isopropyl substituent, along with R–H elimination, to form square-pyramidal [Ir(IPr)(IPr″)(M′R)H][BAr^F₄] (M′R = ZnPh (4a); ZnMe (4b); ZnEt (4c); CdMe (8); IPr″ = dehydrogenated IPr) featuring apical M′R ligands. Heating 1 with 2 equiv ZnPh₂ under H₂ forms [Ir(IPr)₂(ZnPh)₂H₄][BAr^F₄] (5) featuring trans ZnPh ligands. Exposure of 4b-c and 8 to H₂ yields [Ir(IPr)(IPr″)(M′R)H₃][BAr^F₄] (9b-c, 10) as intermediates to highly fluxional [Ir(IPr)₂(M′R)(η²-H₂)H₃][BAr^F₄] (11b-c, 12). Reacting 11b–c with Lewis bases (L) effects [ZnR]⁺ abstraction to give pentahydride Ir(IPr)₂H₅ (13); with 11c and L = IMes (1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), [L₂ZnEt][BAr^F₄] was characterized, whereas with L = PMe₃, both 13 and [Ir(IPr)₂(ZnEt)(PMe₃)H₃][BAr^F₄] (14c) were formed. Reactions of 13 with M′R₂ similarly proceed with R–H elimination to form Ir(IPr)₂(M′R)H₄ (15a-c, 16). Crystallographic and computational analyses characterize a range of hydride ligands, the nature of which depends subtly on the surrounding coordination environment. The new polyhydride complexes reported here add to the small number of such species featuring N-heterocyclic carbene ligands.

Original language	English
Pages (from-to)	1162-1171
Number of pages	10
Journal	Inorganic Chemistry
Volume	65
Issue number	2
Early online date	1 Jan 2026
DOIs	https://doi.org/10.1021/acs.inorgchem.5c04368
Publication status	Published - 19 Jan 2026

Funding

This project has been supported by funding from the EPSRC (Doctoral Training Award for AMW) and The Leverhulme Trust (Award RPG-2022-078 for CMF). We thank Professor Andrew Johnson for the gift of CdMe2, Dr David Liptrot for access to ATR-IR spectroscopy and Dr Kathryn Proctor (Material and Chemical Characterization Facility (MC2)) for mass spectrometry. We dedicate this paper to the memory of Professor Ken Caulton.

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Inorganic Chemistry

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10.1021/acs.inorgchem.5c04368Licence: CC BY

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@article{a175a349b08347d9b65c0c93d39f8c8f,

title = "Cationic and Neutral Heterometallic Ir-Group 12 Element Polyhydride Compounds: Synthesis, Structure and Reactivity",

abstract = "The preparation and reactivity of some Ir–Zn and Ir–Cd heterometallic hydride complexes are described. Treatment of [Ir(IPr)2H2][BArF4] (1; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; ArF = 3,5-C6H3(CF3)2) with M′R2 (M′ = Zn; R = Ph, Me, Et; M′ = Cd, R = Me) and Me3SiCH=CH2 results in dehydrogenation of an IPr isopropyl substituent, along with R–H elimination, to form square-pyramidal [Ir(IPr)(IPr″)(M′R)H][BArF4] (M′R = ZnPh (4a); ZnMe (4b); ZnEt (4c); CdMe (8); IPr″ = dehydrogenated IPr) featuring apical M′R ligands. Heating 1 with 2 equiv ZnPh2 under H2 forms [Ir(IPr)2(ZnPh)2H4][BArF4] (5) featuring trans ZnPh ligands. Exposure of 4b-c and 8 to H2 yields [Ir(IPr)(IPr″)(M′R)H3][BArF4] (9b-c, 10) as intermediates to highly fluxional [Ir(IPr)2(M′R)(η2-H2)H3][BArF4] (11b-c, 12). Reacting 11b–c with Lewis bases (L) effects [ZnR]+ abstraction to give pentahydride Ir(IPr)2H5 (13); with 11c and L = IMes (1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), [L2ZnEt][BArF4] was characterized, whereas with L = PMe3, both 13 and [Ir(IPr)2(ZnEt)(PMe3)H3][BArF4] (14c) were formed. Reactions of 13 with M′R2 similarly proceed with R–H elimination to form Ir(IPr)2(M′R)H4 (15a-c, 16). Crystallographic and computational analyses characterize a range of hydride ligands, the nature of which depends subtly on the surrounding coordination environment. The new polyhydride complexes reported here add to the small number of such species featuring N-heterocyclic carbene ligands.",

author = "Walsh, \{Amber M.\} and Carlos Mart{\'i}n-Fern{\'a}ndez and Lowe, \{John P.\} and Macgregor, \{Stuart A.\} and Mahon, \{Mary F.\} and Whittlesey, \{Michael K.\}",

year = "2026",

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doi = "10.1021/acs.inorgchem.5c04368",

language = "English",

volume = "65",

pages = "1162--1171",

journal = "Inorganic Chemistry",

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publisher = "American Chemical Society",

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T1 - Cationic and Neutral Heterometallic Ir-Group 12 Element Polyhydride Compounds

T2 - Synthesis, Structure and Reactivity

AU - Walsh, Amber M.

AU - Martín-Fernández, Carlos

AU - Lowe, John P.

AU - Macgregor, Stuart A.

AU - Mahon, Mary F.

AU - Whittlesey, Michael K.

PY - 2026/1/19

Y1 - 2026/1/19

N2 - The preparation and reactivity of some Ir–Zn and Ir–Cd heterometallic hydride complexes are described. Treatment of [Ir(IPr)2H2][BArF4] (1; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; ArF = 3,5-C6H3(CF3)2) with M′R2 (M′ = Zn; R = Ph, Me, Et; M′ = Cd, R = Me) and Me3SiCH=CH2 results in dehydrogenation of an IPr isopropyl substituent, along with R–H elimination, to form square-pyramidal [Ir(IPr)(IPr″)(M′R)H][BArF4] (M′R = ZnPh (4a); ZnMe (4b); ZnEt (4c); CdMe (8); IPr″ = dehydrogenated IPr) featuring apical M′R ligands. Heating 1 with 2 equiv ZnPh2 under H2 forms [Ir(IPr)2(ZnPh)2H4][BArF4] (5) featuring trans ZnPh ligands. Exposure of 4b-c and 8 to H2 yields [Ir(IPr)(IPr″)(M′R)H3][BArF4] (9b-c, 10) as intermediates to highly fluxional [Ir(IPr)2(M′R)(η2-H2)H3][BArF4] (11b-c, 12). Reacting 11b–c with Lewis bases (L) effects [ZnR]+ abstraction to give pentahydride Ir(IPr)2H5 (13); with 11c and L = IMes (1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), [L2ZnEt][BArF4] was characterized, whereas with L = PMe3, both 13 and [Ir(IPr)2(ZnEt)(PMe3)H3][BArF4] (14c) were formed. Reactions of 13 with M′R2 similarly proceed with R–H elimination to form Ir(IPr)2(M′R)H4 (15a-c, 16). Crystallographic and computational analyses characterize a range of hydride ligands, the nature of which depends subtly on the surrounding coordination environment. The new polyhydride complexes reported here add to the small number of such species featuring N-heterocyclic carbene ligands.

AB - The preparation and reactivity of some Ir–Zn and Ir–Cd heterometallic hydride complexes are described. Treatment of [Ir(IPr)2H2][BArF4] (1; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; ArF = 3,5-C6H3(CF3)2) with M′R2 (M′ = Zn; R = Ph, Me, Et; M′ = Cd, R = Me) and Me3SiCH=CH2 results in dehydrogenation of an IPr isopropyl substituent, along with R–H elimination, to form square-pyramidal [Ir(IPr)(IPr″)(M′R)H][BArF4] (M′R = ZnPh (4a); ZnMe (4b); ZnEt (4c); CdMe (8); IPr″ = dehydrogenated IPr) featuring apical M′R ligands. Heating 1 with 2 equiv ZnPh2 under H2 forms [Ir(IPr)2(ZnPh)2H4][BArF4] (5) featuring trans ZnPh ligands. Exposure of 4b-c and 8 to H2 yields [Ir(IPr)(IPr″)(M′R)H3][BArF4] (9b-c, 10) as intermediates to highly fluxional [Ir(IPr)2(M′R)(η2-H2)H3][BArF4] (11b-c, 12). Reacting 11b–c with Lewis bases (L) effects [ZnR]+ abstraction to give pentahydride Ir(IPr)2H5 (13); with 11c and L = IMes (1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), [L2ZnEt][BArF4] was characterized, whereas with L = PMe3, both 13 and [Ir(IPr)2(ZnEt)(PMe3)H3][BArF4] (14c) were formed. Reactions of 13 with M′R2 similarly proceed with R–H elimination to form Ir(IPr)2(M′R)H4 (15a-c, 16). Crystallographic and computational analyses characterize a range of hydride ligands, the nature of which depends subtly on the surrounding coordination environment. The new polyhydride complexes reported here add to the small number of such species featuring N-heterocyclic carbene ligands.

UR - https://www.scopus.com/pages/publications/105027627400

U2 - 10.1021/acs.inorgchem.5c04368

DO - 10.1021/acs.inorgchem.5c04368

M3 - Article

C2 - 41478617

AN - SCOPUS:105027627400

SN - 0020-1669

VL - 65

SP - 1162

EP - 1171

JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 2

ER -

Cationic and Neutral Heterometallic Ir-Group 12 Element Polyhydride Compounds: Synthesis, Structure and Reactivity

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