Heterotrimetallic assemblies with 1,2,4,5-tetrakis(diphenylphosphino)benzene bridges: Constructs for controlling the separation and spatial orientation of redox-active metallodithiolene groups

Kumar, S., Selvachandran, M., Wu, C., Pascal, R. A., Zhang, X., Grusenmeyer, T., Schmehl, R. H., Sproules, S. , Mague, J. T. and Donahue, J. P. (2022) Heterotrimetallic assemblies with 1,2,4,5-tetrakis(diphenylphosphino)benzene bridges: Constructs for controlling the separation and spatial orientation of redox-active metallodithiolene groups. Inorganic Chemistry, 61(44), pp. 17804-17818. (doi: 10.1021/acs.inorgchem.2c03112) (PMID:36282620)

Abstract

Metallodithiolene complexes of the type (R2C2S2)M($\eta$2-tpbz) R = CN, Ph, or p-anisyl; M = Ni2+, Pd2+, or Pt2+; tpbz = 1,2,4,5-tetrakis(diphenylphosphino)benzene chelate transition metals ions to form trimetallic arrays (R2C2S2)M(tpbz)]2M']n+, where M' is square planar Pt2+, tetrahedral Cu+, Ag+, or Au+, or octahedral {ReBr(CO)}/{Re(CO)2}+. Forcing conditions (190 °C reflux in decalin, 72 h) are demanded for the Re+ compounds. With third-row metals at the nexus, the compounds are stable to air. Twelve members of the set have been characterized by X-ray diffraction and reveal dithiolene centroid-centroid distances ranging from 22.4 to 24.0 Å. Folding around each tpbz intrachelate P···P axis such that the MP2/M'P2 planes meet the tpbz P2C6P2 mean plane at non-zero values gives rise to core topologies that appear ``S-like'' or herringbone-like for M' = Pt2+ or {ReBr(CO)}/{Re(CO)2}+. Calculations reveal that departure from idealized D2h/D2d/C2v symmetries is induced by steric crowding between Ph groups and that dynamic, fluxional behavior is pertinent to the solution phase because multiple, lower-symmetry minima of comparable energy exist. Spectroscopically, the formation of the trimetallic arrays is marked by a shift of the open end 31P nuclear magnetic resonance signal from approximately -14.5 ppm to approximately +41, approximately +20.5, and approximately +28.5 ppm for M' = Pt2+, Au+, and {ReBr(CO)}/{Re(CO)2}+, respectively. Electrochemically, dithiolene-based oxidations are observed for the R = Ph and M' = Pt2+ or Au+ compounds but at potentials that are anodically shifted relative to charge-neutral (R2C2S2)M]2(μ-tpbz)]. The compounds reported clarify the possibilities for the synthesis of assemblies in which weakly coupled spins may be created in their modular (R2C2S2)M and M' parts.

• Item Type: Articles
• Additional Information: The Louisiana Board of Regents [LEQSF-(2002-03)-ENH-TR-67] and the National Science Foundation (MRI-1228232 and 0619770) are thanked for funding of Tulane University’s X-ray crystallography and mass spectrometry instrumentation, and Tulane University is acknowledged for its ongoing assistance with operational costs for the X-ray diffraction facility. The authors gratefully acknowledge support for this project from the National Science Foundation (CHE-1836589 for S.K. and J.P.D. and CHE-1762452 for R.A.P.).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sproules, Dr Stephen
• Authors: Kumar, S., Selvachandran, M., Wu, C., Pascal, R. A., Zhang, X., Grusenmeyer, T., Schmehl, R. H., Sproules, S., Mague, J. T., and Donahue, J. P.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Inorganic Chemistry
• Publisher: American Chemical Society
• ISSN: 0020-1669
• ISSN (Online): 1520-510X
• Published Online: 24 October 2022
• Copyright Holders: Copyright © 2022 The Authors
• First Published: First published in Inorganic Chemistry 61(44): 17804-17818
• Publisher Policy: Reproduced under a Creative Commons license