title: Spin-Spin Coupling Constants for Iminoboranes RBNH, HBNR, and RBNR and Comparisons with Corresponding Isoelectronic Acetylenes RCCH and RCCR, for R = H, CH3, NH2, OH, and F.
abstract: Ab initio equation-of-motion coupled-cluster singles and doubles method calculations have been performed on iminoboranes RBNH, HBNR, and RBNR, for R = H, CH3, NH2, OH, and F, to evaluate substituent effects on one- and two-bond (15)N-(11)B, (11)B-(1)H, and (15)N-(1)H spin-spin coupling constants. For comparison purposes, (13)C-(13)C coupling constants were evaluated for corresponding isoelectronic molecules RCCH and RCCR. The absolute values of (1)J(N-B) and (1)J(C-C) increase in the series HBNR and RCCH as the σ-electron-withdrawing ability of R increases. In contrast, NH2 substitution at B leads to a decrease in the absolute value of (1)J(N-B), but OH and F substitution increase (1)J(N-B). Disubstitution has dramatically different effects on coupling constants for RCCR and RBNR. In the former, (1)J(C-C) more than doubles relative to the corresponding RCCH and HCCH; in the latter, disubstitution of OH and F decreases (1)J(N-B) relative to the corresponding monosubstituted derivatives, while NH2 substitution increases (1)J(N-B). Changes in one- and two-bond B-H and N-H coupling constants upon substitution are similar to changes observed for (1)J(N-B) in the corresponding monosubstituted derivatives RBNH and HBNR.
authors.affiliation: Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Juan de la Cierva, 3, E-28006 Madrid, Spain, and Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain.
authors.forename: Janet E
authors.initials: JE
authors.lastname: Del Bene
authors.affiliation: Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Juan de la Cierva, 3, E-28006 Madrid, Spain, and Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Elguero
authors.affiliation: Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Juan de la Cierva, 3, E-28006 Madrid, Spain, and Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain.
authors.forename: Ibon
authors.initials: I
authors.lastname: Alkorta
authors.affiliation: Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Juan de la Cierva, 3, E-28006 Madrid, Spain, and Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Yáñez
authors.affiliation: Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Juan de la Cierva, 3, E-28006 Madrid, Spain, and Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain.
authors.forename: Otilia
authors.initials: O
authors.lastname: Mó