Near‐Infrared Emission from Bis‐Pt^II Complexes of Doubly N‐Confused Calix[6]phyrins(1.1.1.1.1.1)

Abstract

Light from confusion: A set of doubly N‐confused calix[6]phyrins bearing two coordination sites (NNNC,NNNC or NNNN,NNCC) were synthesized. Their bis‐PtII complexes exhibit near‐infrared emission around 1000 nm, which could make these compounds ideal for biological applications.

Doubly N‐Confused Calix[6]phyrin Bis‐Organopalladium Complexes: Photostable Triplet Sensitizers for Singlet Oxygen Generation

“…The freebase calix[6]phyrin ligands (transoid, 1 and cisoid, 2)w ere previously reported by our group, which serve as the rectangular-shaped macrocyclicl igands. [14] The two isomeric macrocycles, 1 and 2,i nw hich the arrangement of the nitrogen atomso ft he N-confused pyrrole rings (highlightedi ng reen) is different, provide two organopalladium cation pockets surroundedb ys ymmetrical and unsymmetrical coordination donor sites, "NNNC-NNNC"a nd "NNNN-NNCC", respectively.T he corresponding bis-organopalladium metal complexes, 1-Pd-Pd and 2-Pd-Pd,w ere formeds moothly using 3equivalents of Pd(OAc) 2 under reflux condition in aC H 2 Cl 2 / MeOH mixture, in 60 and 72 %y ields, respectively.A long with the formationofb is-palladium complexes, the mono-palladium complexes, 1-Pd-H 2 and 2-Pd-H 2 ,w ere also formed in 30 % and 22 %y ields, respectively.W hen one equivalent of Pd(OAc) 2 was added into the solution containing al igand 1 or 2,m onopalladium complex, 1-Pd-H 2 or 2-Pd-H 2 wasp redominantly obtained in 80 and7 5% yields, respectively.T he 1 Ha nd 19 FNMR spectroscopy and high-resolution mass spectrometry support the expected structures( cf. Supporting Information).…”

“…The peripheral b-protons appear in the typical sp 2 -CH region due to the non-global p-conjugation as seen in the bis-platinum calixphyrincomplexes. [14] The molecular structureso ft he complexes, 1-Pd-H 2 , 2-Pd-H 2 , 3-Pd-Pd,a nd 4-Pd-Pd,w ere characterizedb yX -ray crystallographic analysis ( Figure 2a nd S7, Table S1). The palladium cations reside in as quare planar geometry in the inner coordination environments for all the complexes.…”

“…The phosphorescence quantum yields and lifetimes of the series of complexes were determined to analyze the triplet [a] Quantum yield was calculated using 4-Pt-Pt (F PL = 0.0027 in toluene, l ex = 532 nm) as Ref. [14]. [ b] Determined by TCSPC method with excitationa t5 32 nm.…”

“…Using this modification strategy,w eh ave also reported novel NIR luminescent dyes based on doubly N-confused calix[6]phyrin(1.1.1.1.1.1)b is-platinum complexes. [14] The core-expansion of the parentc alix[4]phyrins induces the lower energy optical properties as there are more p-electrons in the scaffold. However due to the fact that the complexes possess relativelys hort triplet lifetimes ( % 15 ns) andi nsufficientt riplet energy that couldo therwise allow the energy transfer to dioxygen, the photosensitization for singlet oxygen generation remains yet to be achieved.…”

Synthesis and specific fluoride binding properties of expanded dithiacalixphyrins

“…The macrocycles 3a-c were prepared by condensing one equivalent of 4 with one equivalent of appropriate dipyrromethane 5 in CH 2 Cl 2 in the presence of 0.1 equivalent of TFA under a N 2 atmosphere at room temperature for 1 h followed by oxidation with DDQ in air for additional 1 h. TLC analysis showed mainly one major red spot and absorption spectroscopy showed one broad band at ∼450 nm indicating the formation of a macrocycle. 7,[13][14][15][23][24][25][26][27][28] The crude compound was subjected to alumina column chromatography and afforded the macrocycles 3a-c as orange red solids in 16-19% yields. Although we expected the formation of an expanded macrocycle containing one meso-sp 3 carbon such as compound 6 (Scheme 1), the X-ray structure of one of the macrocycles and detailed NMR studies indicated the formation of an expanded dithiacalixphyrin having two meso sp 3 carbons such as macrocycles 3a-c.…”