A strategy is presented that enables the quantitative assembly of a heterobimetallic [PdPtL4]4+ cage. The presence of two different metal ions (PdII and PtII) with differing labilities enables the cage to be opened and closed selectively at one end upon treatment with suitable stimuli. Combining an inert PtII tetrapyridylaldehyde complex with a suitably substituted pyridylamine and PdII ions led to the assembly of the cage. 1H and DOSY NMR spectroscopy and ESI mass spectrometry data were consistent with the quantitative formation of the cage, and the heterobimetallic structure was confirmed using single‐crystal X‐ray crystallography. The structure of the host–guest adduct with a 2,6‐diaminoanthraquinone guest molecule was determined. Addition of N,N′‐dimethylaminopyridine (DMAP) resulted in the formation of the open‐cage [PtL4]2+ compound and [Pd(DMAP)4]2+ complex. This process could then be reversed, with the reformation of the cage, upon addition of p‐toluenesulfonic acid (TsOH).

A strategy for the generation of heterotrimetallic double cavity (DC) cages [PdnPtmL4]6+ (DC1: n=1, m=2; and DC2: n=2, m=1) is reported. The DC cages were generated by combining an inert platinum(II) tetrapyridylaldehyde complex with a suitably substituted pyridylamine and PdII ions. 1H and DOSY nuclear magnetic resonance spectroscopy (NMR) and electrospray ionization mass spectrometry (ESIMS) data were consistent with the formation of the DC architectures. DC1 and DC2 were shown to interact with several different guest molecules. The structure of DC1, which features two identical cavities, binding two 2,6‐diaminoanthraquinone (DAQ) guest molecules was determined by single‐crystal X‐ray crystallography. In addition, DC1 was shown to bind two molecules of 5‐fluorouracil (5‐FU) in a statistical (non‐cooperative) manner. In contrast, DC2, which features two different cage cavities, was found to interact with two different guests, 5‐FU and cisplatin, selectively.

A new sequential metalation strategy that enables the assembly of a new more robust reduced symmetry heterobimetallic [PdPtL4]4+ cage C is reported. By exploiting a low-symmetry ditopic ligand (L) that...

Detailed kinetic and mechanistic studies have been carried out on the reaction between aquacobalamin/hydroxocobalamin (CblOH2 +/CblOH) and nitroxyl (HNO) generated by Piloty’s acid (PA, N-hydroxybenzenesulfonamide) over a wide pH range (3.5–13). The resulting data showed that in a basic solution HNO can react with hydroxocobalamin to form nitrosylcobalamin despite the inert nature of CblOH. It was shown that at low PA concentrations the rate-determining step is the decomposition of PhSO2NHO– to release HNO, whereas the reaction between CblOH and HNO becomes the rate-determining step at high PA concentrations. Data from kinetic studies on the reaction of CblOH with an excess of HNO enabled us to experimentally determine the pK a(HNO) value from initial rate data as a function of pH, giving pK a(HNO) = 11.47 ± 0.04. An especially interesting observation was made in the neutral pH range, where PA is stable and does not produce HNO. Under such conditions, rapid formation of CblNO was observed in the studied system. The obtained data suggest that CblOH2 + reacts directly with PA to form a Piloty’s acid-bound cobalamin intermediate, which deprotonates rapidly at neutral pH followed by rate-determining S–N bond cleavage to give CblNO and release PhSO2 –.

A strategy is presented that enables the quantitative assembly of a heterobimetallic [PdPtL4]4+ cage. The presence of two different metal ions (PdII and PtII) with differing labilities enables the cage to be opened and closed selectively at one end upon treatment with suitable stimuli. Combining an inert PtII tetrapyridylaldehyde complex with a suitably substituted pyridylamine and PdII ions led to the assembly of the cage. 1H and DOSY NMR spectroscopy and ESI mass spectrometry data were consistent with the quantitative formation of the cage, and the heterobimetallic structure was confirmed using single‐crystal X‐ray crystallography. The structure of the host–guest adduct with a 2,6‐diaminoanthraquinone guest molecule was determined. Addition of N,N′‐dimethylaminopyridine (DMAP) resulted in the formation of the open‐cage [PtL4]2+ compound and [Pd(DMAP)4]2+ complex. This process could then be reversed, with the reformation of the cage, upon addition of p‐toluenesulfonic acid (TsOH).

A new [PdPtL4]4+ heterobimetallic cage containing hydrazone linkages has been synthesised using the sub-component self-assembly approach. 1H and DOSY nuclear magnetic resonance (NMR) spectroscopy and electrospray ionisation mass spectrometry (ESIMS)...

No abstract

A strategy for the generation of heterotrimetallic double cavity (DC) cages [PdnPtmL4]6+ (DC1: n=1, m=2; and DC2: n=2, m=1) is reported. The DC cages were generated by combining an inert platinum(II) tetrapyridylaldehyde complex with a suitably substituted pyridylamine and PdII ions. 1H and DOSY nuclear magnetic resonance spectroscopy (NMR) and electrospray ionization mass spectrometry (ESIMS) data were consistent with the formation of the DC architectures. DC1 and DC2 were shown to interact with several different guest molecules. The structure of DC1, which features two identical cavities, binding two 2,6‐diaminoanthraquinone (DAQ) guest molecules was determined by single‐crystal X‐ray crystallography. In addition, DC1 was shown to bind two molecules of 5‐fluorouracil (5‐FU) in a statistical (non‐cooperative) manner. In contrast, DC2, which features two different cage cavities, was found to interact with two different guests, 5‐FU and cisplatin, selectively.