title: Pt-Mg, Pt-Ca, and Pt-Zn Lantern Complexes and Metal-Only Donor-Acceptor Interactions.
abstract: Pt-based heterobimetallic lantern complexes of the form [PtM(SOCR)4(L)] have been shown previously to form intermolecular metallophilic interactions and engage in antiferromagnetic coupling between lanterns having M atoms with open shell configurations. In order to understand better the influence of the carboxylate bridge and terminal ligand on the electronic structure, as well as the metal-metal interactions within each lantern unit, a series of diamagnetic lantern complexes, [PtMg(SAc)4(OH2)] (1), [PtMg(tba)4(OH2)] (2), [PtCa(tba)4(OH2)] (3), [PtZn(tba)4(OH2)] (4), and a mononuclear control (Ph4P)2[Pt(SAc)4] (5) have been synthesized. Crystallographic data show close Pt-M contacts enforced by the lantern structure in each dinuclear case.195Pt-NMR spectroscopy of 1-4, (Ph4P)2[Pt(SAc)4] (5), and several previously reported lanterns revealed a strong chemical shift dependence on the identity of the second metal (M), mild influence by the thiocarboxylate ligand (SOCR; R = CH3(thioacetate, SAc), C6H5(thiobenzoate, tba)), and modest influence from the terminal ligand (L). Fluorescence spectroscopy has provided evidence for a Pt···Zn metallophilic interaction in [PtZn(SAc)4(OH2)], and computational studies demonstrate significant dative character. In all of 1-4, the short Pt-M distances suggest that metal-only Lewis donor (Pt)-Lewis acceptor (M) interactions could be present. DFT and NBO calculations, however, show that only the Zn examples have appreciable covalent character, whereas the Mg and Ca complexes are much more ionic.
authors.affiliation: Department of Chemistry, Boston University , Boston, Massachusetts 02215, United States.
authors.forename: Frederick G
authors.initials: FG
authors.lastname: Baddour
authors.affiliation: Department of Chemistry, Boston University , Boston, Massachusetts 02215, United States.
authors.forename: Ariel S
authors.initials: AS
authors.lastname: Hyre
authors.affiliation: Department of Chemistry, Boston University , Boston, Massachusetts 02215, United States.
authors.forename: Jesse L
authors.initials: JL
authors.lastname: Guillet
authors.affiliation: Departamento de Química, Centro de Investigación en Síntesis Química, Universidad de La Rioja , Madre de Dios, 51, 26004 Logroño, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Pascual
authors.affiliation: Departamento de Química, Centro de Investigación en Síntesis Química, Universidad de La Rioja , Madre de Dios, 51, 26004 Logroño, Spain.
authors.forename: José Maria
authors.initials: JM
authors.lastname: Lopez-de-Luzuriaga
authors.affiliation: Department of Organic Material Science, Sandia National Laboratories , Albuquerque, New Mexico 87185-0886, United States.
authors.forename: Todd M
authors.initials: TM
authors.lastname: Alam
authors.affiliation: Department of Chemistry, Boston University , Boston, Massachusetts 02215, United States.
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Bacon
authors.affiliation: Department of Chemistry, Boston University , Boston, Massachusetts 02215, United States.
authors.forename: Linda H
authors.identifier: http://orcid.org/0000-0002-2437-6374
authors.initials: LH
authors.lastname: Doerrer