Silver(I) Complexes of 12-Phenylalkynyl- and 12-Triisopropylalkynylcarba-closo-dodecaborate Anions

4 years ago

Silver(I) Complexes of 12-Phenylalkynyl- and 12-Triisopropylalkynylcarba-closo-dodecaborate Anions

Natalia Wolf, Michael Hailmann, Maik Finze

The silver(I) salts of the 12-alkynylcarba-closo-dodecaborate anions [12-RC≡C-closo-1-CB11H11]– {R = Ph (1), SiiPr3 (2)} were obtained by metathesis reactions in aqueous solution. Related reactions afforded the imidazolium salts [EMIm]1 and [MMIm]1. Single crystals of dimeric [(C6H6)Ag1]2 were obtained from benzene. The Ag+ cations are coordinated to the C≡C moiety and to one B–H unit of each anion, and they exhibit further η2-coordination to one of the benzene molecules. [MMIm]1 was studied by single-crystal X-ray diffraction. The triphenylphosphane complexes [(PPh3)Ag1], [(PPh3)Ag2], [(PPh3)2Ag1], and [(PPh3)2Ag2] were obtained from the silver(I) salt and PPh3. In solid [(PPh3)2Ag1] and [(PPh3)2Ag2], the cationic fragment {(PPh3)2Ag}+ interacts with the C≡C moiety, as shown by single-crystal X-ray diffraction. The interaction of the silver(I) cations in [Ag1] and [Ag2] and the {(PPh3)nAg}+ fragments in the respective coordination compounds is evident from the IR spectra and Raman spectra of solid samples and by multinuclear NMR spectroscopy in solution. Spectroscopic and structural data, as well as theoretical data (DFT calculations), display a decrease in the interaction strength between the alkynyl moiety and the silver(I) unit, in the order: Ag+ > {(PPh3)Ag}+ > {(PPh3)2Ag}+.Silver(I) salts of 12-alkynylcarba-closo-dodecaborate anions were synthesized by metathesis reactions. The silver(I) ions are coordinated to the C≡C units and interact with H atoms of the lower B5 belt in [(C6H6)Ag{12-PhC≡C-closo-1-CB11H11}]2. Coordination of PPh3 ligands to the silver(I) ions weakens the interaction between the cationic {(PPh3)nAg}+ fragments and the {closo-1-CB11} cluster.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/ejic.201700379