Search

A series of platinum complexes featuring phosphine and isocyanide ligands [PtX2(PPh3)(CNCy)] (X = Cl, Br, and I) as well as their parent phosphine [PtX2(PPh3)2] and isocyanide [PtX2(CNCy)2] analogues have been prepared and evaluated as catalysts for the photocatalytic hydrosilylation of alkynes. Under violet light irradiation (λmax = 400 nm), phosphine–isocyanides complexes [PtX2(PPh3)(CNCy)] gave high yields of silylated products (product yield up to 99%, TONs up to 1.98 × 103). The blue light irradiation (λmax = 450 nm) was more suitable for the parent phosphine complexes [PtX2(PPh3)2], which showed comparable efficiency (product yield up to 99%, TON up to 1.98 × 103), while isocyanide complexes [PtX2(CNCy)2] were not active. [ABSTRACT FROM AUTHOR]

The PtII isocyanide complex [Pt(ppy)Cl(CNC6H4-C≡C-Ph)] (1, Hppy=2-phenylpyridine) was co-crystallized with 1,4-diiodotetrafluorobenzene (1,4-DITFB), yielding 1·½(1,4-DITFB) adduct. The I···Cl halogen-bonding and π-π-stacking interactions combined with the rare π-hole(isocyano group)⋅⋅⋅dz2[PtII] interactions were identified via analysis of X-ray diffraction data of the co-crystals. These two types of structure-determining interactions supplemented each other, and the system of I⋯Cl and π-hole(isocyano group)⋅⋅⋅dz2[PtII] contacts achieved a 1D extended ladder-type architecture. The density functional theory calculations, employing a set of computational tools, verified the role of I⋯Cl and π-hole(isocyano group)⋅⋅⋅dz2[PtII] noncovalent bonds in the spectrum of noncovalent forces. The solid-state photophysical study revealed an amplification of luminescence intensity in the co-crystals, which is attributed to the suppression of the nonradiative relaxation pathways due to an increase in the rigidity of the chromophore center. [ABSTRACT FROM AUTHOR]

The article titled "Metal-(Acyclic Diaminocarbene) Complexes Demonstrate Nanomolar Antiproliferative Activity against Triple-Negative Breast Cancer" discusses the use of a palladium compound to target aggressive tumors while sparing normal cells and tissues. The authors draw inspiration from the protective figure of Pallas Athena, which symbolizes the original meaning of the word "palladium." The research article provides more detailed information on this topic and can be accessed using the provided DOI. [Extracted from the article]

Phosphorescent PtII-based cyclometalated complexes co-crystallise with bromo- and iodosubstituted perfluorinated arenes to give 1 : 1 adducts. X-FArenes in these co-crystals act as both σh and πh donors forming co-operative C–X⋯Cl–Pt XBs and πh⋯dz2[PtII] contacts. The solid-state photophysical study revealed up to a 2-fold luminescence quantum yield increase upon co-crystallisation due to the formation of these co-operative noncovalent interactions. [ABSTRACT FROM AUTHOR]

Inspection of the X‐ray structures of the newly prepared trans‐[MII(CNXyl)2(DAPT)2]Cl(BF4) (M=Pd, Pt; Xyl=2,6‐Me2C6H3; DAPT=4,6‐diaminopyrimidine‐2(1H)‐thione) complexes and the appropriate Hirshfeld molecular surface analysis allowed the recognition of the previously unknown π‐hole⋅⋅⋅metal interactions between a ligated isocyano group (acting as a π‐hole donor) and the positively charged d8‐PtII and d8‐PdII metal centers (acting as nucleophiles); this is the first identification of π‐hole⋅⋅⋅metal interactions with triple‐bond species. Results of DFT calculations followed by the topological analysis of the electron density distribution within the framework of Bader's theory (quantum theory of atoms in molecules, QTAIM) confirmed the presence of these contacts. The electrostatic surface potential calculations indicated that π‐hole⋅⋅⋅metal contacts are formed upon interaction between the electrophilic isocyano C atom (π‐hole donor) and the nucleophilic dz2 orbital of the metal centers, which act as π‐hole acceptors. Available CCDC data were processed from the perspective of the π‐hole⋅⋅⋅metal interactions with isocyanide ligands, and their analysis disclosed the role of metal nucleophilicity in the corresponding π‐hole acceptor ability. [ABSTRACT FROM AUTHOR]

Reaction of the palladium(II) and platinum(II) isocyanide complexes cis-[MCl2(CNR)2] [M = Pd, R = C6H3(2,6-Me2) (Xyl), 2-Cl-6-MeC6H3, cyclohexyl (Cy), t-Bu, C(Me)2CH2(Me)3 (1,1,3,3-tetramethylbuth-1-yl abbreviated as tmbu); M = Pt, R = Xyl, 2-Cl-6-MeC6H3, Cy, t-Bu, and tmbu] with N,N'-diphenylguanidine (DPG) leads to DPG-derived metal-bound deprotonated acyclic diaminocarbene (ADC) species. This reaction occurs via a two-step process, involving the initial coupling of the guanidine with one of the isocyanides and leading to deprotonated monocarbene monochelated species, while the next addition grants the deprotonated bis-carbene bis-chelated metal compounds. DPG behaves as nucleophile, deprotonating base, and chelator. The addition of DPG proceeded with different regioselectivity depending on the metal center and, in a larger extent, on the substituent R in RNCs. The X-ray diffraction studies for the deprotonated mono- and bis-carbene complexes confirmed the regioisomerism of these species and allowed the identification of ADC protolytic forms stabilized in the solid-state. 1D (1H and 13C{1H}) and 2D (1H,1H-NOESY; 1H,15N-HSQC; 1H,15N-HMBC) solution NMR of the obtained systems demonstrated their configuration isomerism accompanied by prototropic tautomerism. Together, the solid-state and solution data provide an insight into the flexible character of ADC species. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue are Tatiyana Serebryanskaya, Mikhail Kinzhalov and co-workers at St. Petersburg State University, the Research Institute for Physical Chemical Problems, Belarusian State University, Togliatti State University and Blokhin National Medical Research Center of Oncology. The image depicts the shield of Pallas Athena with the structure of a palladium carbene complex that protects against triple-negative breast cancer. Read the full text of the article at 10.1002/chem.202400101., (© 2024 Wiley-VCH GmbH.)