Synthesis and reactions of N-heterocycle functionalised variants of heterometallic {Cr7Ni} rings.

Here we present a series of linked cage complexes of functionalised variants of the octametallic ring {Cr7Ni} with the general formula [(n)Pr2NH2][Cr7NiF8(O2C(t)Bu)15(O2CR)], where HO2CR is a N-heterocycle containing carboxylic acid. These compounds are made by reacting [(n)Pr2NH2][Cr7NiF8(O2C(t)Bu)15(O2CR)] with a variety of simple metal salts and metal dimers. The carboxylic acids studied include iso-nicotinic acid, 3-(4-pyridyl)acrylic acid and 4-pyridazine carboxylic acid.

Molecular nanomagnets with switchable coupling for quantum simulation.

Molecular nanomagnets are attractive candidate qubits because of their wide inter- and intra-molecular tunability. Uniform magnetic pulses could be exploited to implement one- and two-qubit gates in presence of a properly engineered pattern of interactions, but the synthesis of suitable and potentially scalable supramolecular complexes has proven a very hard task. Indeed, no quantum algorithms have ever been implemented, not even a proof-of-principle two-qubit gate.

Rings and threads as linkers in metal-organic frameworks and poly-rotaxanes.

Coordination polymers and metal-organic rotaxane frameworks are reported where the organic linker is replaced by functionalised inorganic clusters that act as bridging ligands.

Chemical control of spin propagation between heterometallic rings.

We present a synthetic, structural, theoretical, and spectroscopic study of a family of heterometallic ring dimers which have the formula [{Cr(7)NiF(3)(Etglu)(O(2)CtBu)(15)}(2)(NLN)], in which Etglu is the pentadeprotonated form of the sugar N-ethyl-D-glucamine, and NLN is an aromatic bridging diimine ligand. By varying NLN we are able to adjust the strength of the interaction between rings with the aim of understanding how to tune our system to achieve weak magnetic communication between the spins, a prerequisite for quantum entanglement. Micro-SQUID and EPR data reveal that the magnetic coupling between rings is partly related to the through-bond distance between the spin centers, but also depends on spin-polarization mechanisms and torsion angles between aromatic rings.

Synthesis, spectroscopy and electronic structure of the vinylidene and alkynyl complexes [W(C=CHR)(dppe)(η-C₇H₇)](+) and [W(C≡CR)(dppe)(η-C₇H₇](n+) (n = 0 or 1).

The first examples of vinylidene complexes of the cycloheptatrienyl tungsten system [W(C=CHR)(dppe)(η-C₇H₇)](+) (dppe = Ph₂PCH₂CH₂PPh₂; R = H, 3; Ph, 4; C₆H₄-4-Me, 5) have been synthesised by reaction of [WBr(dppe)(η-C₇H₇)], 1, with terminal alkynes HC≡CR; a one-pot synthesis of 1 from [WBr(CO)₂(η-C₇H₇)] facilitates its use as a precursor. The X-ray structure of 4[PF₆] reveals that the vinylidene ligand substituents lie in the pseudo mirror plane of the W(dppe)(η-C₇H₇) auxiliary (vertical orientation) with the phenyl group located syn to the cycloheptatrienyl ring. Variable temperature ¹H NMR investigations on [W(C=CH₂)(dppe)(η-C₇H₇)][PF₆], 3, estimate the energy barrier to rotation about the W=C(α) bond as 62.