Metal-Halogen Bonding Seen through the Eyes of Vibrational Spectroscopy

Autor(es)

Oliveira, Vytor P. ^[1] ; Marcial, Bruna L. ^[2] ; Machado, Francisco B. C. ^[1] ; Kraka, Elfi ^[3]

Afiliação do(s) autor(es)

^[1] ITA, Dept Quim, BR-12228900 Sao Paulo - Brazil

^[2] IF Goiano, Nucleo Quim, Campus Morrinhos, BR-75650000 Morrinhos, Go - Brazil

^[3] Southern Methodist Univ, Dept Chem, 3215 Daniel Ave, Dallas, TX 75275 - USA

• Tipo de documento: Artigo Científico
• Fonte: MATERIALS; v. 13, n. 1 JAN 1 2020.
• Citações Web of Science: 9

Resumo

Incorporation of a metal center into halogen-bonded materials can efficiently fine-tune the strength of the halogen bonds and introduce new electronic functionalities. The metal atom can adopt two possible roles: serving as halogen acceptor or polarizing the halogen donor and acceptor groups. We investigated both scenarios for 23 metal-halogen dimers trans-M(Y-2)(NC5H4X-3)(2) with M = Pd(II), Pt(II); Y = F, Cl, Br; X = Cl, Br, I; and NC5H4X-3 = 3-halopyridine. As a new tool for the quantitative assessment of metal-halogen bonding, we introduced our local vibrational mode analysis, complemented by energy and electron density analyses and electrostatic potential studies at the density functional theory (DFT) and coupled-cluster single, double, and perturbative triple excitations (CCSD(T)) levels of theory. We could for the first time quantify the various attractive contacts and their contribution to the dimer stability and clarify the special role of halogen bonding in these systems. The largest contribution to the stability of the dimers is either due to halogen bonding or nonspecific interactions. Hydrogen bonding plays only a secondary role. The metal can only act as halogen acceptor when the monomer adopts a (quasi-)planar geometry. The best strategy to accomplish this is to substitute the halo-pyridine ring with a halo-diazole ring, which considerably strengthens halogen bonding. Our findings based on the local mode analysis provide a solid platform for fine-tuning of existing and for design of new metal-halogen-bonded materials. (AU)

• Processo FAPESP: 18/13673-7 - Desenho de novos reagentes de iodo hipervalente com base em estudos teóricos de elevada acurácia
• Beneficiário: Vytor Pinheiro Oliveira
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado