Biotin Conjugated Fe(III)-Triscatecholate Complex as Tumour Targeting T MRI Contrast Agent via Second Sphere Water Relaxation.

The biotin-conjugated Fe(III) catecholate complex [Fe(BioL)], Fe(BioL) (BioLH=N-(3,4-dihydroxyphenethyl)-5-((3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanamide) is reported as targeted magnetic resonance imaging (MRI) contrast agents (CAs) to increase the payload for early-stage imaging of tumours. The high spin state and octahedral coordination of the Fe(III) complex are confirmed by EPR spectra and DFT optimized structure, respectively. The overall formation constant (log K) of Fe(BioL) is determined as 45, which is higher than the known, more stable complex [Fe(EDTA)].

Alkyl Chain Appended Fe(III) Catecholate Complex as a Dual-Modal MRI-NIR Fluorescence Imaging Agent via Second Sphere Water Interactions.

The C-alkyl chain-conjugated Fe(III) catecholate complex [Fe(CCAT)], () [CCAT = -(3,4-dihydroxyphenethyl)dodecanamide], was synthesized and characterized, reported as a dual-modal -MRI and an optical imaging probe. The DFT-optimized structure of reveals a distorted octahedral coordination geometry around the high spin Fe(III) center. The formation constant (-log K) of was calculated as 45.

Smart dual MRI-optical imaging agent based on a rhodamine appended Fe(III)-catecholate complex.

A rhodamine appended Fe(iii)-catecholate complex Fe(RhoCat)3 is reported as a smart dual-modal T1 MRI-optical imaging probe. The high spin Fe(iii) coordination sphere and rhodamine unit act as MRI and optical reporters, respectively. The probe showed a r1-relaxivity of 4.

Copper(ii)-benzimidazole complexes as efficient fluorescent probes for l-cysteine in water.

Copper(ii) complexes [Cu(L1)(HO)](SOCF)1 and [Cu(L2)(HO)](SOCF)2 based on 2,6-bis(benzimidazolyl)pyridine were synthesized and are reported herein as highly selective "turn-on" optical probes for l-cysteine. The Cu(ii)/Cu(i) redox potential of probe 1 (0.14 V vs.