Bi-ortho-Carborane Unit-Riveted Perylene Monoimides:Structure-Tuned Optical Switches for Electron Transfer and Robust Thin Film-Based Fluorescence Sensors

Innovative design of sensing fluorophores possessing superior photophysical properties,porosity,and packing-resistance structures is pivotal for high performance film-based fluorescent sensors.Herein,PDCB,a perylene monoimide(PMI)derivative incorporating large spatial phenyl-carborane was synthesized and found to exhibit unexpected photophysical properties.The structurally bent PDCB exhibits not only PMI-like emission but also a red-shifted emission.In sharp contrast,PMI-CBH,a linear PMI derivative,exhibits only PMI-like emission.Furthermore,upon local excitation,PDCB undergoes a photoinduced electron transfer(PET)between PMI and phenylcarborane,resulting in a charge-transfer state.Two other PMI derivatives,PCB and PDCBP,showed a similar phenomenon.The PET rate is in the order of PCB(48 ps^(-1))>PDCB(163 ps^(-1))>PDCBP(815 ps^(-1))in toluene,which decreases with increasing steric hindrance,inferring structure reorganization prior to the PET process.As expected,a fabricated PDCB-based sensor showed excellent performance in acetone sensing.

A facile access to mono-C-alkynylated-o-carboranes from o-carboranes and arylsulfonylacetylenes

A facile access to mono-C-alkynyl-o-carboranes from o-carboranes and arylsulfonylacetylenes was developed.This facile process tolerates a wide variety of functional groups,occurs at mild conditions in onepot procedure with short reaction time.The obtained mono-C-alkynyl-o-carboranes can be easily derivatized to synthesize 1,2-difunctionalized o-carboranes.This work provides a useful tool for the functionalization of o-carboranes.

How long a C–C bond can be? An example of extraordinary long C–C single bond in 1,2-diarylamino-o-carborane

How long a C-C bond can be?A question has long fascinated chemists.This work reports an example of extraordinary long C-C bond distance of 1.990(4)?observed in single-crystal X-ray structure of 1,2-(NHMes)2-o-carborane(2;Mes=2,4,6-trimethylphenyl).DFT calculations show that hyperconjugation of lone pairs of the nitrogen atoms into the emptyσ^*orbital of the cage C-C bond is the origin of the bond elongation.Such hyperconjugation can be suppressed if the two nitrogen atoms in 2 are linked to a Lewis acidic germanium(Ⅱ)center.

Structure-fluorescence relationships in pyrrole appended o-carborane crystalline materials

Based on three rationally designed pyrrole-appended o-carborane derivatives,we present that fluores-cence properties of crystalline materials are highly dependent on intermolecular interaction and steric hinderance.Though the three molecules are similar in structure,single crystals of the three compounds showed obvious difference in molecular stacking and fluorescence behavior.Systematic studies indicate that fluorescence quantum yields,thermo-response as well as mechano-response are highly dependent on intermolecular interaction and steric hindrance.In the three crystalline materials,the CB-NMe crys-tals with weaker intermolecular interaction and looser molecular packing showed superior fluorescence quantum yield and temperature sensitivity.Accordingly,surface temperature detection strip with favor-able reversibility is prepared by doping CB-NMe into the polymer.In addition,the CB-NMe aggregates can be used for monitoring bovine serum albumin(BSA)denaturation,as temperature response of the aggregates can be reversed when co-assembled with BSA.

Synthesis and Characterization of Novel Lanthanocene Complexes with Dichalcogenolate o-Carboranyl Ligands

Reactions of [Cp 2Ln(μ-Cl)] 2(Cp=η 5-C 5H 5, Ln=Nd, Yb, Dy, Gd, Er) with an equivalent of [(THF) 3LiE 2C 2B 10H 10Li·(THF)] 2 (E=S, Se) in THF afforded the dinuclear sandwich complexes of formula [Cp 2LnE 2C 2B 10H 10] 2[Li(THF) 4] 2[E=S, Ln=Nd (1a), Yb (2a), Dy (3a), Gd (4a), Er (5a); E=Se, Ln=Nd (1b), Yb (2b), Dy (3b), Gd (4b), Er (5b)]. The molecular structures of complexes 1a, 2a and 2b were determined by the single crystal X-ray structure analyses. Two lanthanide atoms are connected by a pair chalcogen (η 1,η 2-E 2C 2B 10H 10) bridging ligands and the central Ln 2E 2 four membered ring is not planar.