Evidence for efficient anchoring in nitroxyl radical thin films: an experimental XPS/NEXAFS and theoretical DFT/TD-DFT study

Totani, Roberta; Ljubić, Ivan; Mehl, Sascha L.; Kalinovych, Viacheslav; Jugovac, Matteo; Bonano, Gabriele; Ciavardini, Alessandra; Grazioli, Cesare; Galdenzi, Federico; D’Addato, Sergio; de Simone, Monica; Sheverdyaeva, Polina M.; Moras, Paolo; Tsud, Nataliya; Coreno, Marcello (2024) Evidence for efficient anchoring in nitroxyl radical thin films: an experimental XPS/NEXAFS and theoretical DFT/TD-DFT study. Journal of Materials Chemistry C, 12 (19). pp. 6985-6998. ISSN 2050-7526

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Abstract

Studies of persistent organic radical films on conductive metal surfaces can pave the way for diverse applications such as improved spin probes and labels, data control and storage, spintronics, and quantum computing. We grew monolayer films of three nitroxyl radicals (NRs), viz. TEMPO and two carbamoyl-proxyl radicals (nit8 and nit9) under ultra-high vacuum conditions on Au(111) and Cu(111) surfaces. The electronic properties of the films and NR adsorption mechanisms were analyzed by means of X-ray photoelectron (XPS) and absorption (NEXAFS) spectroscopies, with the aid of density functional theory (DFT) and time-dependent DFT computations performed on large unit cells (rev-PBE) and clusters (CAM-B3LYP). We found that all three NRs physisorb weakly on Au. In the case of nit8 and nit9, H-bonded monolayers are formed that recline parallel to the Au surface. Stronger interactions with Cu resulted in chemisorption and robust films, with nit8 and nit9 exhibiting upright orientation due to the amide group acting as an efficient binding anchor. Conversely, TEMPO binds to Cu necessarily via NO which is observed to lead to the destruction of the spin-carrying NO functionality. Computational evidence highlighted the decisive role of Cu surface defects in the partial fragmentation of the CONH2 anchor upon chemisorption of nit8 and nit9.

Item Type:	Article
Uncontrolled Keywords:	XPS ; NEXAFS ; Organic radicals ; Thin films ; Adsorption ; Nitroxide radicals ; Gold surface ; Copper surface ; Density Functional Theory ; Mechanism
Subjects:	NATURAL SCIENCES > Chemistry > Physical Chemistry
Divisions:	Division of Physical Chemistry
Projects:	Project title Project leader Project code Project type Efekt kvantnog tuneliranja: dinamika molekula s kvantnim jezgrama-QuanTunMol Marko Tomislav Cvitaš IP-2020-02-9932 HRZZ Fotoinducirani procesi u molekulama: Susret teorije i eksperimenta Nađa Došlić IP-2022-10-4658 HRZZ
Depositing User:	Ema Buhin Šaler
Date Deposited:	13 Apr 2026 12:36
URI:	http://fulir.irb.hr/id/eprint/11673
DOI:	10.1039/D4TC00427B

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