Novel Types of Tetra-, Hexa-, Octa-, and Dodecanuclear Silver Clusters Containing (2,7-Di-tert-butylfluoren-9-ylidene)methanedithiolate^†

Abstract

The reaction of AgClO(4) with piperidinium 2,7-di-tert-butyl-9H-fluorene-9-carbodithioate (pipH)[S(2)C(t-Bu-Hfy)] (1) (t-Bu-Hfy = 2,7-di-tert-butylfluoren-9-yl) afforded [Ag(n){S(2)C(t-Bu-Hfy)}(n)] (2), which reacted with phosphines to give [Ag{S(2)C(t-Bu-Hfy)}L(2)] [L = PPh(3) (3a); L(2) = bis(diphenylphosphino)ethane (dppe, 3b), 1,1'-bis(diphenylphosphino)ferrocene (dppf, 3c). By reacting complex 2 with AgClO(4) and piperidine in a 1:1:1 molar ratio, the dodecanuclear cluster [Ag(12){S(2)C(t-Bu-fy)}(6)] (4) (t-Bu-fy = 2,7-di-tert-butylfluoren-9-ylidene) was obtained. Compound 4 can also be directly prepared from the reaction of 1 with AgClO(4) and piperidine in a 1:2:1 molar ratio. The reactions of 1 with AgClO(4), phosphines, and piperidine afforded the compounds [Ag(6){S(2)C(t-Bu-fy)}(3)L(5)] [1:2:2:1 molar ratio; L = PPh(3) (5a), P(p-To)(3) (5b)], [Ag(4){S(2)C(t-Bu-fy)}(2)(dppf)(2)] (6) (1:2:1:1 molar ratio), [Ag(n){S(2)C(t-Bu-fy)}(n/2){P(i-Pr)(3)}(n)] (7) (1:2:2:1 molar ratio), or [Ag(8){S(2)C(t-Bu-fy)}(4){P(i-Pr)(3)}(4)] (8) (1:2:1:1 molar ratio). Complexes 5a,b, 6, 7, and 8 can be also obtained by reacting 4 with the corresponding phosphine in the appropriate molar ratio. The crystal structures of 4, 5b, and 8 have been determined by X-ray diffraction studies. The nuclearity of complex 6 was established from its (31)P{(1)H} NMR data, which reveal a very fast dynamic process leading to an average coupling of each of the P atoms of the dppf ligands with four Ag atoms.

Argentophilic Interactions

“…The transannular Ag–Ag distances are 2.9425(4) and 2.9872(4) Å, but there are additional Ag–Ag contacts of similar length (2.9958(4)–3.0702(4) Å) between the rings which represent the remaining four edges of the central Ag 4 tetrahedron 335. Similar arrangements have been found in fluoren‐9‐ylidene‐methanedithiolates ( 105 , fluoren‐9‐ylidene for PR 3 ) 336. This family of compounds was later studied by DFT calculations 337…”

“…[335] Similar arrangements have been found in fluoren-9-ylidene-methanedithiolates (105, fluoren-9-ylidene for PR 3 ). [336] This family of compounds was later studied by DFT calculations. [337] Compounds of type 82 with X and Y representing carbon atoms are extremely rare, and no crystal structures have been determined.…”

Argentophile Wechselwirkungen

“…[335] ¾hnliche Anordnungen hat man in Fluoren-9-yliden-methandithiolaten gefunden (105; Fluoren-9yliden für PR 3 ). [336] Diese Familie von Verbindungen wurde später mit DFT-Rechnungen untersucht. [337] Verbindungen des Typs 82, in denen X und Y Kohlenstoffatome sind, kommen sehr selten vor, und es wurden noch keine Kristallstrukturen bestimmt.…”

Synthesis and Molecular Structures of the Cationic Silver Complexes of the Polycondensed Aromatics Fluorene, Pseudorubrene, and Truxene

“…Examples are acenaphthylene, 9,9‐bifluoreneylidene, benzo[ e ]acephenanthrylene, decacyclene, and fluoranthene or indene . Especially, fluorene derivatives have been studied for their coordination behavior towards Ag I , for example, as efficient π‐prismands,, in coordination frameworks with Ag 3 /Ag 4 arrangements, and as ligands in molecular Ag n clusters of moderate size ( n = 4, 6, 8, 12) …”

“…Therein, it was shown that primarily the use of readily available silver(I) perchlorate and silver(I) trifluoromethanesulfonate (triflate, Tfl) enables the formation of multibranched network structures through bridging perchlorate or sulfonate units. Recently, multibranched Ag I coordination compounds with cyclophanes, fullerenes, and silver‐encapsulated PAH molecules for the construction of metal–organic frameworks (MOFs), have driven additional interest in the community. Moreover, it was shown that coordination of Ag I to PAH molecules can drastically improve the electrical properties relative to those of the parent aromatic molecule and may thus offer an additional scope for exploring the functional properties of Ag I coordination compounds of PAHs …”