Metal‐Carbene‐Templated Photochemistry in Solution: A Universal Route towards Cyclobutane Derivatives

Abstract

Summary of main observation and conclusion A series of dicarbene‐bridged metallacycles [Ag2(1)2](PF6)2, [Ag2(2)2](BF4)2, [Ag2(3)2](PF6)2, [Ag2(7)2](BF4)2, [Ag2(8)2](BF4)2 and [Ag2(11)2](PF6)2 were obtained in high yields via the reactions of 1,2,4‐triazole‐, 1,2,3‐triazole‐ and imidazo[1,5‐a]pyridine‐based ligands with Ag2O in CH3CN. The C=C double bonds in all of the newly synthesized metallacycles went through [2 + 2] photodimerization under UV irradiation condition (λ = 365 nm, T = 298 K) yielding the dinuclear rctt‐cyclobutane‐silver(I) complexes [Ag2(4)](PF6)2, [Ag2(5)](BF4)2, [Ag2(6)](PF6)2, [Ag2(9)](BF4)2, [Ag2(10)](BF4)2 and [Ag2(12)](PF6)2, respectively with quantitative yields. Treatment of the these cyclobutane‐bridged silver(I) complexes with NH4Cl resulted in the exclusive formation of cyclobutane derivatives after removal of the silver(I) metal ions.

Photooxidation of IR‐820 by Calixpyridinium‐Induced Assembled Material and Its pH‐Controlled Visual Multicolor Luminescence

“…reported several metallosupramolecular template‐directed photochemical reactions. [ 9‐10 ] Light‐responsive host–guest supramolecular materials of water‐soluble macrocycles and photoactive molecules are environmentally friendly [ 11‐15 ] and they have been widely used in the fields of photodynamic therapy, [ 16 ] soft lithography, [ 17 ] molecular switch, [ 18 ] and disease treatment. [ 19 ] It is noted that UV light is the generally effective light stimulus in constructing these light‐responsive materials, while visible light that is more benign and harmless is rarely used.…”

Construction of Metallacycle‐Linked Heteroarm Star Polymers via Orthogonal Post‐Assembly Polymerization and Their Intriguing Self‐Assembly into Large‐Area and Regular Nanocubes†

“…According to the general principles of coordination‐driven self‐assembly, [ 16‐28 ] a new 120° dipyridyl donor 1 containing hydroxy group (Figure S1) for the ring‐opening polymerization and 120° di‐Pt(II) acceptor 2 decorated with chain transfer agent (CTA) were selected for the construction of a discrete hexagonal metallacycle. [ 29‐36 ] As shown in Scheme 1, the complexation reaction was conducted by mixing an equimolar mixture of 1 and 2 in a solution of acetone and water ( V : V = 5 : 1) at 50 °C for 5 h. From the 1 H NMR analysis of the resultant complex, the protons of the pyridine rings exhibited obvious downfield shifts ( α ‐H Py , δ 0.40; β ‐H Py , δ 0.42) as compared to the uncoordinated ligands, which are associated with the loss of electron density upon coordination by the pyridine‐N atom with the platinum metal centers (Figure 1).…”

Strategies for the construction of supramolecular assemblies from poly-NHC ligand precursors

“…Carbene ligands, similar to phosphines, have strong σ-donor and relatively weak π-acceptor properties and are widely employed as carbon donors for the construction of supramolecular assemblies [16]. After the pioneering work initiated by Öfele and Wanzlick [17] in 1968, the chemistry of organometallic assemblies bearing N-heterocyclic carbene (NHC) ligands has evolved rapidly because of their fascinating structures and potential applications in diverse fields [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. There remains a lack of focused review that summarises the synthetic strategies employed in the synthesis of supramolecular assemblies from poly-NHC precursors.…”