N-heterocyclic carbene Pt(II) complexes from caffeine: synthesis, structures and photoluminescent properties

Jian Jin Hu; Shi-Qiang Bai; Hsiu Hsuan Yeh; David J. Young; Yun Chi; T. S. Andy Hor

doi:10.1039/c0dt01380c

N-heterocyclic carbene Pt(II) complexes from caffeine: synthesis, structures and photoluminescent properties

Jian Jin Hu
, Shi-Qiang Bai
, Hsiu Hsuan Yeh
, David J. Young^*
, Yun Chi
, T. S. Andy Hor^*

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

46 Citations (Scopus)

Abstract

The caffeine-derived N-heterocyclic carbene (NHC) complex [Pt^II(C^∧N)(NHC)Cl] (C^∧N = 2-phenylpyridine), 4 has the opposite stereochemistry and a shorter Pt-C_carbene bond compared to that of an analogous benzimidazole-derived N,N-heterocyclic carbene (NNHC) Pt complex 2. These suggest a lower trans influence of pyridyl N compared to cyclometallated carbon and an increased Pt-NHC π-backbonding because of decreased π-donation resulting from conjugation to the electron deficient pyrimidine of caffeine. Complex 4 has a lower emission quantum yield (Φ) and is blue-shifted into the green region of the visible spectrum relative to non-carbene Pt(II) cyclometalated complex 5.

Original language	English
Pages (from-to)	4402-4406
Journal	Dalton Transactions
Volume	40
Issue number	17
Online published	14 Mar 2011
DOIs	https://doi.org/10.1039/c0dt01380c
Publication status	Published - 7 May 2011
Externally published	Yes

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title = "N-heterocyclic carbene Pt(II) complexes from caffeine: synthesis, structures and photoluminescent properties",

abstract = "The caffeine-derived N-heterocyclic carbene (NHC) complex [PtII(C∧N)(NHC)Cl] (C∧N = 2-phenylpyridine), 4 has the opposite stereochemistry and a shorter Pt-Ccarbene bond compared to that of an analogous benzimidazole-derived N,N-heterocyclic carbene (NNHC) Pt complex 2. These suggest a lower trans influence of pyridyl N compared to cyclometallated carbon and an increased Pt-NHC π-backbonding because of decreased π-donation resulting from conjugation to the electron deficient pyrimidine of caffeine. Complex 4 has a lower emission quantum yield (Φ) and is blue-shifted into the green region of the visible spectrum relative to non-carbene Pt(II) cyclometalated complex 5.",

author = "Hu, \{Jian Jin\} and Shi-Qiang Bai and Yeh, \{Hsiu Hsuan\} and Young, \{David J.\} and Yun Chi and Hor, \{T. S. Andy\}",

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doi = "10.1039/c0dt01380c",

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TY - JOUR

T1 - N-heterocyclic carbene Pt(II) complexes from caffeine

T2 - synthesis, structures and photoluminescent properties

AU - Hu, Jian Jin

AU - Bai, Shi-Qiang

AU - Yeh, Hsiu Hsuan

AU - Young, David J.

AU - Chi, Yun

AU - Hor, T. S. Andy

PY - 2011/5/7

Y1 - 2011/5/7

N2 - The caffeine-derived N-heterocyclic carbene (NHC) complex [PtII(C∧N)(NHC)Cl] (C∧N = 2-phenylpyridine), 4 has the opposite stereochemistry and a shorter Pt-Ccarbene bond compared to that of an analogous benzimidazole-derived N,N-heterocyclic carbene (NNHC) Pt complex 2. These suggest a lower trans influence of pyridyl N compared to cyclometallated carbon and an increased Pt-NHC π-backbonding because of decreased π-donation resulting from conjugation to the electron deficient pyrimidine of caffeine. Complex 4 has a lower emission quantum yield (Φ) and is blue-shifted into the green region of the visible spectrum relative to non-carbene Pt(II) cyclometalated complex 5.

AB - The caffeine-derived N-heterocyclic carbene (NHC) complex [PtII(C∧N)(NHC)Cl] (C∧N = 2-phenylpyridine), 4 has the opposite stereochemistry and a shorter Pt-Ccarbene bond compared to that of an analogous benzimidazole-derived N,N-heterocyclic carbene (NNHC) Pt complex 2. These suggest a lower trans influence of pyridyl N compared to cyclometallated carbon and an increased Pt-NHC π-backbonding because of decreased π-donation resulting from conjugation to the electron deficient pyrimidine of caffeine. Complex 4 has a lower emission quantum yield (Φ) and is blue-shifted into the green region of the visible spectrum relative to non-carbene Pt(II) cyclometalated complex 5.

UR - https://www.scopus.com/pages/publications/79954586786

UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-79954586786&origin=recordpage

U2 - 10.1039/c0dt01380c

DO - 10.1039/c0dt01380c

M3 - RGC 21 - Publication in refereed journal

C2 - 21409198

SN - 1477-9226

VL - 40

SP - 4402

EP - 4406

JO - Dalton Transactions

JF - Dalton Transactions

IS - 17

ER -

N-heterocyclic carbene Pt(II) complexes from caffeine: synthesis, structures and photoluminescent properties

Abstract

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