5,11,17,23,29,35-Hexa-tert-butyl-37,38,39,40,41,42-hexa­kis­(eth­oxy­carbonyl­meth­oxy)calix[6]arene acetonitrile disolvate

In the title compound, C90H120O18·2CH3CN, the calix[6]arene has a 1,2,3-alternate conformation and possesses inversion symmetry. It crystallizes as an acetonitrile disolvate, with a half-mol­ecule of calix[6]arene and one mol­ecule of solvent in the asymmetric unit. In the crystal, the two solvent mol­ecules are enclosed in voids between the calix[6]arene mol­ecules. They form weak C—H⋯O hydrogen bonds involving an O atom of the lower rim substituent. The cavity of the calix[6]arene itself is enclosed by two opposite phenol rings, which are turned into the cavity due to the presence of a C—H⋯π inter­action. The calix[6]arene mol­ecule exhibits disorder of one substituent on its lower rim [occupancy ratio 0.897 (3):0.103 (3)]

Rapid synthesis of graphene quantum dots using a continuous hydrothermal flow synthesis approach.

A rapid, continuous, environmentally benign and innovative approach is employed for the synthesis of green fluorescent graphene quantum dots (GQD) with low cytotoxicity by utilising a Continuous Hydrothermal Flow Synthesis (CHFS) process as an efficient cutting tool in combination with calix[4]arene tetrasulfonic acid (SCX4) as an effective particle size limiting agent

Vanadyl sulfates:molecular structure, magnetism and electrochemical activity

Reaction of differing amounts of vanadyl sulfate with p-tert-butylthiacalix[4]areneH4 and base allows access to the vanadyl-sulfate species [NEt4]4[(VO)4(3-OH)4(SO4)4]∙1/2H2O (1), [HNEt3]5[(VO)5(3-O)4(SO4)4]∙4MeCN (2∙4MeCN) and [NEt4]2[(VO)6(O)2(SO4)4(OMe)(OH2)]∙MeCN (3∙MeCN). Similar use of p-tert-butylsulfonylcalix[4]areneH4, p-tert-butylcalix[8]areneH8 or p-tert-butylhexahomotrioxacalix[3]areneH3 led to the isolation of [HNEt3]2[H2NEt2]2[VO(OMe)]2p-tert-butylcalix[8-SO2]areneH2] (4), [HNEt3]2[V(O)2p-tert-butylcalix[8]areneH5] (5) and [HNEt3]2[VIV2VV4O11(OMe)8] (6), respectively. Dc magnetic susceptibility measurements were performed on powdered microcrystalline samples of 1-3 in the T = 300 - 2 K temperature range. Preliminary screening for electrochemical water oxidation revealed some activity for 2 with turnover frequency (TOF) and number (TON) of 2.2 × 10-4 s-1 and 6.44 × 10-6 (mmol O2 / mmol cat.), respectively. The compound 3 showed an improved electrochemical activity in the presence of water. This is related to the increased number and the rate of electrons exchanged during oxidation of V4+ species, facilitated by protons generated in the water discharge process

A Simple Tetraminocalix[4]arene as a Highly Efficient Catalyst under "On-Water" Conditions through Hydrophobic Amplification of Weak Hydrogen Bonds

8The simple tetraminocalix[4]arene 1, which contains weak H-bond-donor NH2 groups, is reported to be a highly efficient organocatalyst for the Vinylogous Mukaiyama Aldol Reaction (VMAR) of 2-(trimethylsilyloxy)furan 5 with α-ketoesters 6 a-l under "on-water" conditions owing to the hydrophobic amplification of weak H-bond interactions. The catalytic efficiency of calixarene catalyst 1 was shown to be closely related to its recognition abilities towards the reactants 5 and 6 through a multipoint recognition model. The proposed model provided good explanations for the differences on the reaction rate acceleration and on the stereoselectivity observed with different substrates.partially_openembargoed_20180509De Rosa, Margherita; La Manna, Pellegrino; Soriente, Annunziata; Gaeta, Carmine; Talotta, Carmen; Hickey, Neal; Geremia, Silvano; Neri, PlacidoDe Rosa, Margherita; La Manna, Pellegrino; Soriente, Annunziata; Gaeta, Carmine; Talotta, Carmen; Hickey, JAMES NEIL; Geremia, Silvano; Neri, Placid