Area I. 3d Metal Alkynyls for Materials

The chemistry of 3d metal alkynyls supported by polyaza macrocyclic ligands was generally underdeveloped compared to those based on 4d / 5d metals with soft auxiliary ligands. Our recent efforts demonstrated that the trans-[M(cyclam)(C₂R)₂]⁺ type (cyclam = 1,4,8,11-tetraazacyclotetradecane) compounds can be readily prepared from reactions between [M(cyclam)Cl₂]⁺ and LiC₂R for M = Cr(III), Fe(III), and Co(III). Furthermore, both the trans-[Co(cyclam)(C₂R)Cl]⁺ and {trans-[Co(cyclam)Cl]₂(m-(C≡C)_n)}²⁺ type compounds can be prepared through a dehydrohalogenation reaction. The latter compounds provided a chance to assess the electronic coupling across oligoyn-diyls between two M(cyclam) units. Cr(III) centered phosphorescence has been studied for a number of Cr(cyclam') type complexes, where cyclam' represents C-substituted cyclam.

Most recently, the stepwise alkynylation at Co^III(cyclam) center enabled the preparation of the donor-bridge-acceptor (D-B-A) dyads, where the donor is aniline or related arylamine, and the acceptor is N-alkyl-1,8-naphthalimide (NAP). Currently, the evolution of NAP-based excited states in Co-based D-B-A and its modulation through the excitation of Co-bound C≡C bonds are being investigated.

Selected References:

General review: Ren, T. Chem. Commun. 2016, 52, 3271-3279; "A Sustainable Metal Alkynyl Chemistry: 3d Metals and Polyaza Macrocyclic Ligands"; http://dx.doi.org/10.1039/c5cc09365a.

Recent Publications:

Natoli, S. N.; Azbell, T. J.; Fanwick, P. E.; Zeller, M.; Ren, T. Organometallics 2016, 35, 3594-3603; "A Synthetic Approach to Cross-pi-Conjugated Organometallic Systems Based on geminal-Diethynylethene and CoIII(cyclam)"; http://dx.doi.org/10.1021/acs.organomet.6b00657.

Cook, T. D.; Natoli, S. N.; Fanwick, P. E.; Ren, T. Organometallics 2016, 35, 1329-1338; "CoIII(cyclam) Oligoynyls: Monomeric Oligoynyl Complexes  and Dimeric Complexes with an Oligoyn-diyl Bridge"; http://dx.doi.org/10.1021/acs.organomet.6b00219.

Tyler, S. F.; Judkins, E.; Song, Y.; Cao, F.; McMillin, D. R.; Fanwick, P. E.; Ren, T. Inorg. Chem. 2016, 55, 8736-8743; "Cr(III)-HMC (HMC = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) Alkynyl Complexes - Preparation and Emission Properties"; http://dx.doi.org/10.1021/acs.inorgchem.6b01285.

Cao, Z.; Forrest, W. P.; Gao, Y.; Fanwick, P. E.; Ren, T. Organometallics 2012, 31, 6199-6206; "trans-[Fe(cyclam)(C2R)2]+: A New Family of Fe(III) Bis-Alkynyl Compounds"; http://dx.doi.org/10.1021/om300515r.