In this work, we designed and synthesized a heterobimetallic ruthenium(II)–nickel(II) complex, [Ru(bpy)2(phen-DPA)Ni](PF6)4 (Ru–Ni), as a highly selective phosphorescence probe for histidine. The probe exhibited weak emission at 603 nm because the phosphorescence of the Ru(II) complex can be strongly quenched by the paramagnetic Ni2+ ion. In the presence of histidine, reaction of Ru–Ni with histidine resulted in the release of nickel(II) and an enhancement in the phosphorescence intensity at 603 nm. Ru–Ni showed high selectivity for histidine even in the presence of other amino acids and cellular abundant species. Cell imaging experimental results demonstrated that Ru–Ni is membrane permeable, and can be applied for visualizing histidine in live cells. More interestingly, Ru–Ni also can act as a novel reaction-based nuclear staining agent for visualizing exclusively the nuclei of living cells with a significant phosphorescence enhancement. In addition, the potential of the probe for biological applications was confirmed by employing it for phosphorescence imaging of histidine in larval zebrafish and Daphnia magna. These results demonstrated that Ru–Ni would be a useful tool for physiological and pathological studies involving histidine.

A novel heterobimetallic ruthenium(II)–gadolinium(III) complex, Ru–Gd, comprising a luminescent Ru(II) complex, [Ru(bpy)2(phen)]2+ (bpy: 2,2′-bipyridine; phen: 1,10-phenanthroline), and a Gd(III) complex, DOTA–Gd3+ (DOTA: 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), has been designed and synthesized as a magnetoluminescent dual-modal imaging agent. The heterobimetallic complex Ru–Gd is water-soluble, biocompatible with low cytotoxicity, strongly luminescent with a long luminescence lifetime and a large Stokes shift, and has comparable longitudinal relaxivity r1 (4.71 mM−1 s−1), which enable the complex to be suitable for luminescence bioimaging and T1-weighted MR imaging. Using Ru–Gd as a contrast agent, the T1-weighted MRI of a Kunming (KM) mouse was successfully carried out. The results demonstrated the availability and validity of our approach for the development of magnetoluminescent dual-modal imaging agents.

Developments of ratiometric bioprobes are highly appealing due to the superiority of their self-calibration capability for the quantitative biotracking. In this work, we designed and synthesized a novel lanthanide complex-based ratiometric luminescence probe, [4′-(2,4-dinitrophenyloxy)-2,2′:6′,2″-terpyridine-6,6″-diyl]bis(methylenenitrilo) tetrakis(acetate)-Eu3+/Tb3+ (NPTTA-Eu3+/Tb3+), for the specific recognition and quantitative time-gated luminescence detection of hydrogen sulfide (H2S) in aqueous and living cell samples. Due to the presence of the photoinduced electron transfer (PET) process from the terpyridine-Eu3+/Tb3+ moiety to 2,4-dinitrophenyl (DNP), the probe itself is weakly luminescent. In physiological pH aqueous media, the reaction of NPTTA-Eu3+/Tb3+ with H2S leads to the cleavage of DNP moiety from the probe molecule, which affords the deprotonated (4′-hydroxy-2,2′:6′,2″-terpyridine-6,6″-diyl)bis(methylenenitrilo) tetrakis(acetate)-Eu3+/Tb3+ and terminates the PET process. Meanwhile, the intensity of Tb3+ emission at 540 nm is remarkably increased, while that of the Eu3+ emission at 610 nm is slightly decreased. After the reaction, the intensity ratio of Tb3+ emission to Eu3+ emission, I540/I610, was ∼220-fold increased, and the dose-dependent enhancement of I540/I610 showed a good linearity upon the increase of H2S concentration with a detection limit of 3.5 nM. This unique luminescence response allowed NPTTA-Eu3+/Tb3+ to be conveniently used as a ratiometric probe for the time-gated luminescence detection of H2S with I540/I610 as a signal. In addition, the applicability of the probe for the quantitative time-gated luminescence imaging of intracellular H2S in living cells was investigated. The results demonstrated the efficacy and advantage of the new probe for the time-gated luminescence cell imaging application.

A novel dinuclear ruthenium(II)–copper(II) complex, [Ru(bpy)2(phen-cyc)Cu](PF6)4 (bpy: 2,2′-bipyridine; cyc: 1,4,7,10-tetraazacyclododecane; phen: 1,10-phenanthroline), has been designed and synthesized by conjugating a ruthenium(II) complex with a cyclen-Cu2+ complex. This has almost no luminescence due to the efficient quenching by Cu2+ of the luminescence of the ruthenium(II) complex. In aqueous media, the reaction of [Ru(bpy)2(phen-cyc)Cu](PF6)4 with hydrogen sulfide results in the release of the Cu2+ from the azamacrocyclic ring, accompanied by a ∼130-fold increase in the luminescence intensity at 605 nm with a 159 nm Stokes shift. The dose-dependent luminescence enhancement shows a good linearity in a concentration range of 2.0 to 20 μM, with a detection limit of 21.6 nM for hydrogen sulfide. In addition, the luminescence response of [Ru(bpy)2(phen-cyc)Cu](PF6)4 to hydrogen sulfide is very rapid and widely available in the pH range of 3.0–9.5. It also has excellent selectivity so it can distinguish hydrogen sulfide with no interference by other anions and amino acids. On the basis of these features, a rapid, highly selective and sensitive luminescence method for the detection of hydrogen sulfide under physiological conditions was established, using [Ru(bpy)2(phen-cyc)Cu](PF6)4 as a probe.

By using an anthryl-substituted 2,2′-bipyridine as a singlet oxygen-reactive ligand, a new class of Ru(II)-bipyridine complex derivatives that can specifically respond to singlet oxygen with remarkable phosphorescence enhancements have been successfully developed.

The concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) were measured in 23 farmland soil samples and 10 riverine sediment samples from Guiyu, China, and the carcinogenic risks associated with PAHs in the samples were evaluated. Guiyu is the largest electronic waste (EW) dismantling area globally, and has been well known for the primitive and crude manner in which EWs are disposed, such as by open burning and roasting. The total PAH concentrations were 56–567 ng/g in the soils and 181–3034 ng/g in the sediments. The Shanglian and Huamei districts were found to be more contaminated with PAHs than the north of Guiyu. The soils were relatively weakly contaminated but the sediments were more contaminated, and sediments in some river sections might cause carcinogenic risks to the groundwater system. The PAHs in the soils were derived from combustion sources, but the PAHs in the sediments were derived from both combustion and petroleum sources.Download high-res image (565KB)Download full-size image

By using an anthryl-substituted 2,2′-bipyridine as a singlet oxygen-reactive ligand, a new class of Ru(II)-bipyridine complex derivatives that can specifically respond to singlet oxygen with remarkable phosphorescence enhancements have been successfully developed.

In this work, we designed and synthesized a heterobimetallic ruthenium(II)–nickel(II) complex, [Ru(bpy)2(phen-DPA)Ni](PF6)4 (Ru–Ni), as a highly selective phosphorescence probe for histidine. The probe exhibited weak emission at 603 nm because the phosphorescence of the Ru(II) complex can be strongly quenched by the paramagnetic Ni2+ ion. In the presence of histidine, reaction of Ru–Ni with histidine resulted in the release of nickel(II) and an enhancement in the phosphorescence intensity at 603 nm. Ru–Ni showed high selectivity for histidine even in the presence of other amino acids and cellular abundant species. Cell imaging experimental results demonstrated that Ru–Ni is membrane permeable, and can be applied for visualizing histidine in live cells. More interestingly, Ru–Ni also can act as a novel reaction-based nuclear staining agent for visualizing exclusively the nuclei of living cells with a significant phosphorescence enhancement. In addition, the potential of the probe for biological applications was confirmed by employing it for phosphorescence imaging of histidine in larval zebrafish and Daphnia magna. These results demonstrated that Ru–Ni would be a useful tool for physiological and pathological studies involving histidine.

A novel dinuclear ruthenium(II)–copper(II) complex, [Ru(bpy)2(phen-cyc)Cu](PF6)4 (bpy: 2,2′-bipyridine; cyc: 1,4,7,10-tetraazacyclododecane; phen: 1,10-phenanthroline), has been designed and synthesized by conjugating a ruthenium(II) complex with a cyclen-Cu2+ complex. This has almost no luminescence due to the efficient quenching by Cu2+ of the luminescence of the ruthenium(II) complex. In aqueous media, the reaction of [Ru(bpy)2(phen-cyc)Cu](PF6)4 with hydrogen sulfide results in the release of the Cu2+ from the azamacrocyclic ring, accompanied by a ∼130-fold increase in the luminescence intensity at 605 nm with a 159 nm Stokes shift. The dose-dependent luminescence enhancement shows a good linearity in a concentration range of 2.0 to 20 μM, with a detection limit of 21.6 nM for hydrogen sulfide. In addition, the luminescence response of [Ru(bpy)2(phen-cyc)Cu](PF6)4 to hydrogen sulfide is very rapid and widely available in the pH range of 3.0–9.5. It also has excellent selectivity so it can distinguish hydrogen sulfide with no interference by other anions and amino acids. On the basis of these features, a rapid, highly selective and sensitive luminescence method for the detection of hydrogen sulfide under physiological conditions was established, using [Ru(bpy)2(phen-cyc)Cu](PF6)4 as a probe.