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ARTICLE This journal is © The Royal Society of Chemistry 2013J. Name., 2013, 00, 1-3 | 1 The one-pot reaction of 3,5-di-tert-butyl-2-hydroxybenzaldehyde, (R)-2-aminoglycinol and Cu(OAc)2·2H2O in a 1:1:1 ratio in the presence of triethylamine led to the isolation of X-ray quality crystals of the chiral complex (R)-1 in high yield. The single crystal structure of (R)-1 reveals a tetranuclear copper(II) complex that contains a {Cu4(μ-O)2(μ3-O)2N4O4} core. A reaction using (1S,2R)-2-amino-1,2-diphenylethanol as precursor under the same conditions generated the chiral complex (S,R)-2; its structure was determined by single crystal X-ray crystallography and was found to contain a {Cu2(μ-O)2N2O2} core. Both (R)-1 and (S,R)-2 have been used for catalytic aerobic oxidation of benzylic alcohols in combination with the TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxyl) radical. (R)-1 selectively catalyses the conversion of various aromatic primary alcohols to the corresponding aldehydes with high yields (99%) and TONs (up to 770) in the air, while (S,R)-2 exhibits less promising catalytic performance under the same reaction conditions. The role of the cluster structures in (R)-1 and (S,R)-2 in controlling the reactivity towards aerobic oxidation reactions is discussed. IntroductionThe oxidation of alcohols to carbonyl compounds is an important transformation in synthetic organic chemistry and extensive efforts have been focused on the development of atom-economic oxidation methodologies for such reactions. [1][2][3][4] Amongst the protocols developed to date, catalytic aerobic oxidation has proven to be especially efficient and valuable by virtue of the use of a low-loaded, low-cost catalyst and molecular oxygen from the air. [5][6][7][8][9][10] In the past two decades, copper-catalysed, TEMPO (2,2,6,6-tetramethylpiperidinyl-1-oxyl) mediated aerobic oxidation has been the most popular choice of catalyst systems since the pioneering work of Semmelhack and coworkers in 1984. These authors utilized a CuCl/TEMPO system in DMF (N,N-dimethylformamide) to furnish the aerobic oxidation of benzylic and allylic alcohols. 11 Recent progress indicates that both Cu(I) and Cu(II) complexes with a N,N-or N,O-ligands in combination with TEMPO could be efficient catalysts or catalyst precursors for the aerobic oxidation of various alcohols, and of particular note is a highly efficient copper/2,2'-bipyridine/TEMPO system developed by the Stahl group. 12-17 However, the types of organic ligands exploited in the copper catalyst systems are still limited and the structures of copper catalysts involved in the catalytic process are rarely explored. [17][18][19][20] The construction of metal-organic cluster compounds through self-assembly of predesigned ligands with appropriate metal ions is a prime research topic [21][22][23][24][25] Herein, we report the one-pot syntheses and crystal structures of two tetranuclear and dinuclear copper(II) complexes resulting from the in situ synthesis of chiral Schiff base ligands (Scheme 1), and their catalytic ap...

In developed, non-agricultural, unsewered areas, septic systems and fertilizer application to lawns and gardens represent two major sources of nitrogen to coastal groundwater, in addition to atmospheric input. This study was designed to distinguish between these two possible nitrogen sources by analyzing groundwater samples for pharmaceutical residuals, because fertilizers do not contain any of these pharmaceuticals, but domestic wastewater commonly does. In addition, several herbicides and insecticides used in lawn treatment were analyzed as indicators of nitrogen delivery to groundwater from fertilizers. Groundwater samples were taken through piezometres at shoreline sites in unsewered areas surrounding Northport Harbor and in sewered areas adjacent to Manhasset Bay (hereafter referred to as "Northport" and "Manhasset", respectively), both in northwestern Long Island, USA. Excessive nitrogen loading has led to reduced dissolved oxygen concentrations in Long Island Sound, and the groundwater contribution to the nitrogen budget is poorly constrained. The frequent detection of the anticonvulsant compound carbamazepine in groundwater samples of the Northport Harbor area (unsewered), together with the fact that few pesticides associated with lawn applications were detected, suggests that wastewater input and atmospheric input are the likely sources of nitrogen in the Northport groundwater. High concentrations of nitrogen were also detected in the Manhasset (sewered) groundwater. The low detection frequency and concentration of carbamazepine, however, suggest that the sewer system effectively intercepts nitrogen from wastewater there. The likely sources of nitrogen in the Manhasset groundwater are atmospheric deposition and lawn fertilizers, as this area is densely populated.