In recent years, significant progress has been made in the surface functionalization of magnetic nanoparticles (MNPs), revolutionizing their utility in multimodal imaging, drug delivery, and catalysis. This progression, spanning over the last decade, has unfolded in discernible phases, each marked by distinct advancements and paradigm shifts. In the nascent stage, emphasis was placed on foundational techniques, such as ligand exchange and organic coatings, establishing the groundwork for subsequent innovations. This review navigates through the cutting-edge developments in tailoring MNP surfaces, illuminating their pivotal role in advancing these diverse applications. The exploration encompasses an array of innovative strategies such as organic coatings, inorganic encapsulation, ligand engineering, self-assembly, and bioconjugation, elucidating how each approach impacts or augments MNP performance. Notably, surface-functionalized MNPs exhibit increased efficacy in multimodal imaging, demonstrating improved MRI contrast and targeted imaging. The current review underscores the transformative impact of surface modifications on drug delivery systems, enabling controlled release, targeted therapy, and enhanced biocompatibility. With a comprehensive analysis of characterization techniques and future prospects, this review surveys the dynamic landscape of MNP surface functionalization over the past three years (2021–2023). By dissecting the underlying principles and applications, the review provides not only a retrospective analysis but also a forward-looking perspective on the potential of surface-engineered MNPs in shaping the future of science, technology, and medicine.

Two formal palladium carbene complexes, [PC(sp²)P]Pd(PR₃) (3: R = Me; 4: R = Ph) were isolated and characterized from [PC(sp³)H₂P] ([PC(sp³)H₂P] = bis[2-(di-isopropylphosphino)phenyl]methane, ⁱPr₂P-C₆H₄-CH₂-C₆H₄-PⁱPr₂). Structural studies and DFT calculations indicate that the interaction between palladium and carbon is best described as a single bond, associated with nucleophilic character at that carbon atom. The characteristics of 3 were probed by reactions with electrophiles (MeI), acids (MeOH and HCl), and para-toluidine.

Magnetic nanoparticles (MNPs) have evolved tremendously during recent years, in part due to the rapid expansion of nanotechnology and to their active magnetic core with a high surface-to-volume ratio, while their surface functionalization opened the door to a plethora of drug, gene and bioactive molecule immobilization. Taming the high reactivity of the magnetic core was achieved by various functionalization techniques, producing MNPs tailored for the diagnosis and treatment of cardiovascular or neurological disease, tumors and cancer. Superparamagnetic iron oxide nanoparticles (SPIONs) are established at the core of drug-delivery systems and could act as efficient agents for MFH (magnetic fluid hyperthermia). Depending on the functionalization molecule and intrinsic morphological features, MNPs now cover a broad scope which the current review aims to overview. Considering the exponential expansion of the field, the current review will be limited to roughly the past three years.

A series of palladium(ii) persistent radical carbene complexes, [PC˙(sp²)P]PdX (X = Cl, Br, I), was synthesized from the nucleophilic carbene [PC(sp²)P]PdPMe₃.

The reactivity of two nucleophilic palladium carbenes, [PC(sp²)P]Pd(PMe₃) and [PC(sp²)P]Pd(PPh₃), where [PC(sp²)P] = bis[2-(di-iso-propylphosphino)phenyl]methylene, toward the E–H bond activation of Ph_4−nEH_n (E = Si, Ge; n = 1–3) and pinacolborane (HBpin) is discussed. Unlike previous reports, both types of isomer species, hydride [PC(EH_n−1Ph_4−n)P]PdH or [PC(Bpin)P]PdH and silyl/germyl [PC(H)P]Pd(EH_n−1Ph_4−n), were observed depending on the substrate and the phosphine ligand, showing that the polarity of the Pd–C bond can be tuned by the phosphine substituents.

The reactivity of a nucleophilic palladium carbene, [PC(sp²)P]Pd(PMe₃) (1; [PC(sp²)P] = bis[2-(diisopropylphosphino)phenyl]methylene), toward the C–H bonds of CH₃COCH₃, CH₃CN, Ph–CCH, fluorene, and 9,10-dihydroanthracene was investigated. All surveyed substrates reacted with 1. However, there was no detectable reaction of 1 with Ph₂CH₂. It is proposed that the pK_a values of the studied C–H bonds govern their reactivity toward 1: our results show that substrates with a pK_a higher than 29, such as Ph₂CH₂ (pK_a = 32.2), do not react even with prolonged heating.