Homoleptic Silver Complexes of the Cages P4Se3 and As4S3

• Published in: European journal of inorganic chemistry 2019-03, Vol.2019 (11-12), p.1657-1668
• Main Authors: Weis, Philippe, Hettich, Clarissa, Kratzert, Daniel, Krossing, Ingo
• Format: Article
• Language: English
• Subjects: Anions; Cages; Coordination chemistry; Coordination compounds; Dichloromethane; Inorganic chemistry; Ions; Ligands; Mass spectrometry; NMR spectroscopy; Raman spectroscopy; Selenium; Silver; Solvents; Weakly coordinating anion (WCA)
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201800743

By reacting P4Se3 and As4S3 with Ag[Al(ORF)4] {–RF = –C(CF3)3 or –hfip [= –C(H)(CF3)2]} in suitable solvents, Ag(P4Se3)[Al(Ohfip)4] (1), Ag(P4Se3)2[Al(ORF)4] (2), Ag(P4Se3)3[Al(ORF)4] (3), Ag2(As4S3)3[Al(ORF)4]2 (4) and Ag(As4S3)2[Al(ORF)4] (5) were synthesized and characterized by SC‐XRD, Mass spectrometry, Raman spectroscopy as well as solution NMR spectroscopy. When using stronger coordinating anions, only P4Se3 forms an isolable complex yielding 1 featuring a [Ag2(P4Se3)2]2+ core capped by anions acting as the first example of P4Se3 coordinating through selenium atoms. Upon using the weakly coordinating anion [Al{OC(CF3)3}4]–, the dimeric complexes 2 and 4 are accessible in dichloromethane or ortho‐difluorobenzene (o‐dfb), respectively. Complex 2 shows isolated [Ag2(P4Se3)4(CH2Cl2)2]2+ dications with a [Ag2(P4Se3)2]2+ core similar to 1. Complex 4 shows isolated [Ag2(As4S3)3]2+ dications featuring a weak argentophilic contact. All of these complexes include solvent molecules or anions in the coordination sphere of the metal. When switching to the polar yet non‐coordinating solvent SO2, the coordination spheres are filled with additional ligands and compounds 3 and 5 form. Complex 3 shows condensed [Ag(P4Se3)3]+ units yielding a one dimensional chain and represents the first homoleptic metal(P4Se3) complex. Complex 5 shows a similar paddle wheel structure as in 4 with interconnecting As4S3 ligands and is the first known example of a homoleptic metal(As4S3) complex. To be or not to be coordinated, that is the question investigated by the study of the coordination behavior of the weakly basic cage molecules P4Se3 and As4S3. Using suitable Ag[WCA] salts and the polar yet non‐coordinating solvent SO2 made it possible to characterize the homoleptic complexes of these ligands, whereas stronger coordinating anions or solvents such as CH2Cl2 and ortho‐difluorobenzene yield dimeric structures displaying new coordination modes.