Crystal engineering of luminescent gold(I) compounds of 2-amino-5-mercapto-1,3,4-thiadiazolate and 6-amino-2-mercaptobenzothiazolate

Treatment of monophosphine gold(I) complex [P(CH2CH2CN)(3)(AuCl)] or bisphosphine gold(I) complex [dpph(AuCl)(2), dpph = 1,6-bis(diphenylphosphino)hexane] with sodium 2-amino-5-mercapto-1,3,4-thiadiazolate (NaSSNH2) or sodium 6-amino-2-mercaptobenzothiazolate (NaSSCNH2) affords a series of gold(I) thiolates: [P(CH2CH2CN)(3)(Au(SSNH2))] 1, [dpph(Au(SSNH2))(2)] 2, [P(CH2CH2CN)(3)(AU(SSCNH2))] 3, and [dpph(Au(SSCNH2))(2)] 4. The crystal structures of 1 and 1-DMF feature a similar ribbon pattern with molecules linked through hydrogen-bonding interactions, and 2-DMF displays a novel pseudo double-helical structure assembled into a two-dimensional sheet via hydrogen bonding. When the SSNH2 ligand is replaced by SSCNH2, the cyano group of the P(CH2CH2CN)(3) complex engaging in hydrogen-bonding interactions contributes to the formation of a two-dimensional sheet structure for 3. Complex 4, featuring a dinuclear S-shaped structure, is further associated into a one-dimensional chain via a weak N-(HS)-S-... interaction. In the present work, the bulky P(CH2CH2CN)(3) ligands prevent gold(I)(...)gold(I) interactions in their complexes, but allow interesting hydrogen-bonding interactions. Somewhat unexpectedly, even complexes 2 and 4 bearing the more flexible dpph ligands do not display aurophilic interactions in the solid state. In addition, the frameworks studied herein all show photoluminescence upon incorporation of gold(I) centers, and potential applications in chemical sensing may be anticipated.