Single versus Double Cu(I) Catalyzed [3 + 2] Azide/Platinum Diacetylide Cycloaddition Reactions

Abstract

This report focuses on Cu­(I) catalyzed cycloaddition reactions between organic azides and the platinum diacetylide complexes trans-(PR3)2Pt­(CCR′)2 (where PR3 = P­(OEt)3, PEt3, P n Bu3, PPhMe2, PPh3, and PBn3; and R′ = H, Ph, and p-PhNO2). Pt­(II)-Diacetylides supported by P­(OEt)3, PEt3, P n Bu3, and PPhMe2 react with benzyl azide to provide syn/anti isomers of double cycloaddition products. In contrast, Pt­(II)-diacetylide complexes supported by PPh3 and PBn3 afford single cycloaddition products, exclusively. Steric congestion enforced by the larger phosphines PPh3 and PBn3 prevent the second cycloaddition. Ground state DFT computations provide some insight into the divergent reactivity and indicate that the π-acidity of the phosphine ligands is a variable in the single vs double cycloaddition outcome.

(Spectro)electrochemical Properties of Anthracene Containing Triarylamine Platinum(II) Acetylides

“…The filtrate was concentrated and purified by column chromatography using AlOx and a gradient of n-hexane into n-hexane:CH 2 Cl 2 (1 : 1). Orange crystals of trans-4 were obtained in 81 % yield (89 mg, 0.57 mmol) 1…”

“…This was repeated for purification of the platinum complex. cis-5 was obtained as an orange powder in 45 % yield (60 mg, 0.04 mmol), 1…”

“…This was repeated for purification of the platinum complex. trans-5 was obtained as an orange powder in 86 % yield (52 mg, 0.03 mmol); 1 (31 mg, 0.03 mmol) and trans-5 (204 mg, 0.13 mmol) were dissolved in dichloromethane and the resulting red solution purified through a layer of silica eluted with n-hexane (6) followed by a 1 : 1 mixture of n-hexane/CH 2 Cl 2 , which removed trans-4. All volatiles of the two fractions were removed under reduced pressure and the resulting orange (trans-4) and dark red solid (6) received after evaporation of the solvent.…”

“…All volatiles of the two fractions were removed under reduced pressure and the resulting orange (trans-4) and dark red solid (6) received after evaporation of the solvent. Further purification of 6 was achieved by recrystallization from n-hexane with a yield of 90 % (100 mg, 0.12 mmol, based on trans-5), 1…”

“…Transition metal acetylides represent a class of compounds with versatile structural compositions [1][2][3] and numerous interesting properties that range from liquid crystallinity, [4] chemi- [5] and photo-physical luminescence [6,7] as well as non-linear optical behavior. [8,9] Due to these properties, materials derived from transition metal acetylide complexes have been proposed for applications such as light-emitting diodes, [10] low dimensional conductors [11] and semiconductors, [12] as well as variable optical attenuators [13] for photon based information transmission.…”