Cyanate clusters

Azide, thiocyanate, and cyanate also have been shown to bind to Cluster C (152). Although they are weak inhibitors of the enzyme, they cause marked changes in the EPR spectrum of Cluster C (153), converting the Credi state (with all g-values below 2) to a state in which all g-values are above 2. 

On the basis of recent studies, a model for the mechanism of CO2 reduction was proposed. In this model, fully oxidized CODH ([(COL)Fe2+-NF+]4+) and CODH at the C edi state ([(COL)Fe +-Ni +-H ] +) are unable to reduce CO2 to CO. CO2 reduction only occurs effectively when the putative [Fe-NiFe3S4] subcluster is fully reduced [(COL)Fe +-Ni +-H ] + (Cunc state).The B-cluster mediates electron flow from the C-center to the external electron acceptors in R. rubrum CODH and to the A-cluster via the 13.8-A-long hydrophobic channel in M. thermoacetica CODH. Cyanate, thiocyanate, and azide have been shown to bind to the C-center and inhibit CO oxidation. ... 

Self-supported chiral titanium clusters were prepared by mixing the ligand and titanium alkoxide in anhydrous toluene, followed by addition of a small amount of water (Scheme 7.22). In some cases, the cluster was completely insoluble in the reaction medium, especially in the case of 30. The cyanation works well with this heterogeneous catalyst, which was reused many times with no significant loss of activity. Additional experiments revealed that no appreciable amount of chiral catalyst had leached into the solution and the enantioselectivity came only from the solid catalyst. 

Strecker reaction A robust heterogeneous self-supported chiral titanium cluster (SCTC) catalyst applied both in batch and continuous mode [44] enabled imine cyanation as well as a three-component Strecker reaction using the corresponding aldehydes and amines under continuous flow conditions in a PBR giving aminonitriles enantiomeric excess values of up to 98%. 

Seayad, A.M., Ramalingam, B., Chai, C.LL, Li, C., Garland, M.V., and Yoshinaga, K. (2012) Self-supported chiral titanium cluster (SCTC) as a robust catalyst for the asymmetric cyanation of imines under batch and continuous flow at room temperature. Chem. Eur. J., 18, 5693-5700. doi 10.1002/chem.201200528... 

Similarly, the cyanate ligand in the cluster Ru4(CO)i3(NCO) may be decar-benylated upen heating te yield nitride clusters which can be enlarged by a sequence ef redex cendensatien reactiens. 

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