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Two new copper(II) complexes (1 and 2) with reduced L -histidine Schiff bases were synthesized and characterized using single-crystal X-ray diffraction, powder X-ray diffraction, UV-visible spectroscopy, and thermal analysis. Single-crystal analysis reveals that 5-methyl-containing 1 possesses a simple phenoxo-bridged binuclear unit, while 5-bromine-substituted 2 possesses a metal–organic cage (MOC) structure. The as-prepared complexes as artificial metallohydrolases displayed catalytic activity towards the hydrolysis of both PNPP (p-nitrophenyl picolinate) and PNPA (p-nitrophenyl acetate). These two complexes provided 28-fold (for 1) and 39-fold (for 2) rate enhancements in comparison with spontaneous hydrolysis of PNPA, respectively. With regard to PNPP, its hydrolysis was accelerated by two orders of magnitude in the presence of 1 or 2. Additionally, positive micellar effects of bis(hexadecyldimethylammonium)hexane bromide (16-6-16) and N-octyldocosylammonium bromide (C22H45N(CH3)2C8H17Br, abbr. C22/8) were observed for the PNPA hydrolysis by 1 or 2, resulting in 1.3 to 3.9 times acceleration compared to that in buffered aqueous solution. In micellar solution of N,N-dimethyl-n-lauroylsarcosine sodium (LSS), no obvious rate enhancement was observed for the PNPA hydrolysis by 1 or 2. [ABSTRACT FROM AUTHOR]

Three novel binuclear copper(II) complexes with reduced L -serine Schiff bases were synthesized and their structures were analyzed with single-crystal X-ray diffraction and DFT calculations. The crystal data revealed that all of these binuclear complexes are chiral. Both 5-halogenated (bromo- and chloro-) binuclear complexes exhibit right-handed helix structural character. Interestingly, the 5-methyl-containing analogue has a two-dimensional pore structure. In this paper, the esterolysis reactivity of the as-prepared complexes shows that in the hydrolysis of p-nitrophenyl acetate (PNPA) these three complexes provide 26, 18, 40-fold rate acceleration as compared to the spontaneous hydrolysis of PNPA at pH 7.0, respectively. Under selected conditions, in excess buffered aqueous solution a rate enhancement by three orders of magnitude was observed for the catalytic hydrolysis of another carboxylic ester, p-nitrophenyl picolinate (PNPP). These complexes efficiently promoted PNPP hydrolysis in a micellar solution of cetyltrimethylammonium bromide (CTAB), giving rise to a rate enhancement in excess of four orders of magnitude, which is approximately 2.0–3.2 times higher than that in the buffer. [ABSTRACT FROM AUTHOR]