Universität zu Köln

Garbe, Simon, Krause, Maren, Klimpel, Annika, Neundorf, Ines ORCID: 0000-0001-6450-3991, Lippmann, Petra, Ott, Ingo ORCID: 0000-0002-8087-4618, Brunink, Dana, Strassert, Cristian A., Doltsinis, Nikos L. and Klein, Axel ORCID: 0000-0003-0093-9619 (2020). Cyclometalated Pt Complexes of CNC Pincer Ligands: Luminescence and Cytotoxic Evaluation. Organometallics, 39 (5). S. 746 - 757. WASHINGTON: AMER CHEMICAL SOC. ISSN 1520-6041

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Abstract

In the framework of our attempts to develop cyclometalated Pt(II) complexes toward bifunctional targeting inhibitors or agents for photodynamic therapy, diagnostics, and bioimaging, a series of bis-cyclometalated Pt(II) complexes [Pt(CNC)(L)] (L = DMSO, MeCN) containing various (CNC)(2-) ligands based on 2,6-diphenylpyridine were synthesized and characterized analytically and spectroscopically, focusing on their electrochemical, luminescence, and antiproliferative properties. Electrochemical experiments and UV-vis absorption spectroscopy suggest ligand-centered LUMOs and metal-centered HOMOs in line with DFT calculations. Extension of the ancillary phenyl to naphthyl cores and a central 4-phenylpyridine group instead of pyridine results in bathochromic shifts of the long-wavelength absorption bands ranging from 420 to 440 nm, with the latter shift being more pronounced. The complexes of the fused CNC heterocyclic systems dba (H(2)dba = dibenzo[c,h] acridine), db(ph)a (H(2)db(ph)a = 7-phenyldibenzo[c,h]acridine), and bzqph (HbzqphH = 2-phenylbenzo[h]quinoline) absorb far more red-shifted in the range 500-530 nm. All complexes show reversible first electrochemical reductions and irreversible oxidations with an electrochemical gap of about 3 V, roughly in line with the absorption energies. While the 2,6-diphenylpyridine complexes [Pt(CNC)(DMSO)] show no luminescence at ambient temperature in solution, the fused dba, db(ph)a, and bzqph derivatives are efficient triplet emitters at ambient temperature with emission wavelengths in the region 575-600 nm and quantum yields ranging from 7 to 23%. Vibrationally resolved emission spectra calculated in the framework of DFT faithfully reproduce the experimental data. TD-DFT calculations at the excited-state T-1 geometry reveal intraligand, pi-pi*/MLCT character of the emission for all three investigated complexes. Antiproliferative tests on selected complexes gave very different toxicities, ranging from lower than 1 mu M to virtually nontoxic. The data allowed drawing some structure-activity relationships (SAR), even though variations in solubility could also significantly account for the different toxicities.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Garbe, Simon UNSPECIFIED UNSPECIFIED UNSPECIFIED Krause, Maren UNSPECIFIED UNSPECIFIED UNSPECIFIED Klimpel, Annika UNSPECIFIED UNSPECIFIED UNSPECIFIED Neundorf, Ines UNSPECIFIED orcid.org/0000-0001-6450-3991 UNSPECIFIED Lippmann, Petra UNSPECIFIED UNSPECIFIED UNSPECIFIED Ott, Ingo UNSPECIFIED orcid.org/0000-0002-8087-4618 UNSPECIFIED Brunink, Dana UNSPECIFIED UNSPECIFIED UNSPECIFIED Strassert, Cristian A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Doltsinis, Nikos L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Klein, Axel UNSPECIFIED orcid.org/0000-0003-0093-9619 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-341324
DOI:	10.1021/acs.organomet.0c00015
Journal or Publication Title:	Organometallics
Volume:	39
Number:	5
Page Range:	S. 746 - 757
Date:	2020
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	1520-6041
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Inorganic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ZETA VALENCE QUALITY; GAUSSIAN-BASIS SETS; PLATINUM(II) COMPLEXES; SPECTROSCOPIC PROPERTIES; PHOTOPHYSICAL PROPERTIES; ORGANOPLATINUM(II) COMPLEXES; CRYSTAL-STRUCTURES; PT(II) COMPLEX; EXCITED-STATE; ATOMS LI Multiple languages Chemistry, Inorganic & Nuclear; Chemistry, Organic Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/34132