Light Activation and Photophysics of a Structurally Constrained Nickel(II)-Bipyridine Aryl Halide Complex.

Transition-metal photoredox catalysis has transformed organic synthesis by harnessing light to construct complex molecules. Nickel(II)-bipyridine (bpy) aryl halide complexes are a significant class of cross-coupling catalysts that can be activated via direct light excitation. This study investigates the effects of molecular structure on the photophysics of these catalysts by considering an underexplored, structurally constrained Ni(II)-bpy aryl halide complex in which the aryl and bpy ligands are covalently tethered alongside traditional unconstrained complexes.

Determining the key vibrations for spin relaxation in ruffled Cu(ii) porphyrins resonance Raman spectroscopy.

Pinpointing vibrational mode contributions to electron spin relaxation () constitutes a key goal for developing molecular quantum bits (qubits) with long room-temperature coherence times. However, there remains no consensus to date as to the energy and symmetry of the relevant modes that drive relaxation. Here, we analyze a series of three geometrically-tunable = ½ Cu(ii) porphyrins with varying degrees of ruffling distortion in the ground state.

Anisotropy Elucidates Spin Relaxation Mechanisms in an = 1 Cr(IV) Optically Addressable Molecular Qubit.

Paramagnetic molecules offer unique advantages for quantum information science owing to their spatial compactness, synthetic tunability, room-temperature quantum coherence, and potential for optical state initialization and readout. However, current optically addressable molecular qubits are hampered by rapid spin-lattice relaxation () even at sub-liquid nitrogen temperatures. Here, we use temperature- and orientation-dependent pulsed electron paramagnetic resonance (EPR) to elucidate the negative sign of the ground state zero-field splitting (ZFS) and assign anisotropy to specific types of motion in an optically addressable = 1 Cr(-tolyl) molecular qubit.

μ-Oxo Dimerization Effects on Ground- and Excited-State Properties of a Water-Soluble Iron Porphyrin CO Reduction Catalyst.

Iron 5,10,15,20-tetra(-,,-trimethylanilinium)porphyrin (Fe--TMA) is a water-soluble catalyst capable of electrochemical and photochemical CO reduction. Although its catalytic ability has been thoroughly investigated, the mechanism and associated intermediates are largely unknown. Previous studies proposed that Fe--TMA enters catalytic cycles as a monomeric species.

1,3,2-Diazaborole-derived carbene complexes of boron.

Reaction of 2-bromo-1,3,2-diazaborole (1) with excess BBr induces 1,2-hydrogen migration, giving 1,3,2-diazaborole-derived carbene complexes of boron bromide (2). Compound 2 exists in a dynamic solution equilibrium with 1. The H NMR study shows that the equilibrium lies to the right side of the dissociation reaction of 2.