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Dey Baksi S, Aggrey JO, Bhuvanesh N, Gladysz JA. Reactions of Platinum Terminal Polyynyl Complexes trans-(C 6F 5)( p-tol 3P) 2Pt(C≡C) nH ( n = 2-4) and n-BuLi, Generation of Functional Equivalents of Pt(C≡C) nLi Species, and Derivatization with Organic and Inorganic Electrophiles. Organometallics 2024; 43:1041-1050. [PMID: 38756992 PMCID: PMC11094795 DOI: 10.1021/acs.organomet.4c00098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/01/2024] [Accepted: 04/09/2024] [Indexed: 05/18/2024]
Abstract
Reactions of the title complexes and n-BuLi (1.5 equiv, -45 °C) afford functional equivalents of the deprotonated species trans-(C6F5)(p-tol3P)2Pt(C≡C)nLi (n = 2-4), as assayed by subsequent additions of MeI or Me3SiCl to give trans-(C6F5)(p-tol3P)2Pt(C≡C)nMe (66-52%) or trans-(C6F5)(p-tol3P)2Pt(C≡C)nSiMe3 (63-49%). However, 31P NMR data suggest more complicated mechanistic scenarios, and small amounts of the hydride complex trans-(C6F5)(p-tol3P)2PtH (independently synthesized from the chloride complex, AgClO4, and NaBH4) are detected in most cases. Analogous sequences involving trans-(C6F5)(p-tol3P)2Pt(C≡C)2H and benzyl bromide, D2O, or W(CO)6/Me3O+ BF4- similarly afford products with Pt(C≡C)2Bn, Pt(C≡C)2D, or Pt(C≡C)2C(OCH3)=W(CO)5 linkages. The crystal structures of the tungsten and corresponding SiMe3 adduct, the three Pt(C≡C)nMe species, and hydride complex are determined.
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Affiliation(s)
- Sourajit Dey Baksi
- Department
of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas 77842-3012, United States
| | - Joshua O. Aggrey
- Department
of Chemistry, East Tennessee State University, 1276 Gilbreath Drive, Johnson City, Tennessee 37614, United States
| | - Nattamai Bhuvanesh
- Department
of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas 77842-3012, United States
| | - John A. Gladysz
- Department
of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas 77842-3012, United States
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2
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Arora A, Baksi SD, Weisbach N, Amini H, Bhuvanesh N, Gladysz JA. Monodisperse Molecular Models for the sp Carbon Allotrope Carbyne; Syntheses, Structures, and Properties of Diplatinum Polyynediyl Complexes with PtC20Pt to PtC52Pt Linkages. ACS CENTRAL SCIENCE 2023; 9:2225-2240. [PMID: 38161378 PMCID: PMC10755852 DOI: 10.1021/acscentsci.3c01090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 01/03/2024]
Abstract
Extended conjugated polyynes provide models for the elusive sp carbon polymer carbyne, but progress has been hampered by numerous synthetic challenges. Stabilities appear to be enhanced by bulky, electropositive transition-metal endgroups. Reactions of trans-(C6F5)(p-tol3P)2Pt(C≡C)nSiEt3 (n = 4-6, PtCxSi (x = 2n)) with n-Bu4N+F-/Me3SiCl followed by excess tetrayne H(C≡C)4SiEt3 (HC8Si) and then CuCl/TMEDA and O2 give the heterocoupling products PtCx+8Si, PtCx+16Si, and sometimes higher homologues. The PtCx+16Si species presumably arise via protodesilylation of PtCx+8Si under the reaction conditions. Chromatography allows the separation of PtC16Si, PtC24Si, and PtC32Si (from n = 4), PtC18Si and PtC26Si (n = 5), or PtC20Si and PtC28Si (n = 6). These and previously reported species are applied in similar oxidative homocouplings, affording the family of diplatinum polyynediyl complexes PtCxPt (x = 20, 24, 28, 32, 36, 40 in 96-34% yields and x = 44, 48, 52 in 22-7% yields). These are carefully characterized by 13C NMR, UV-visible, and Raman spectroscopy and other techniques, with particular attention to behavior as the Cx chain approaches the macromolecular limit and endgroup effects diminish. The crystal structures of solvates of PtC20Pt, PtC24Pt, and PtC26Si, which feature the longest sp chains structurally characterized to date, are analyzed in detail. All data support a polyyne electronic structure with a nonzero optical band gap and bond length alternation for carbyne.
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Affiliation(s)
| | | | - Nancy Weisbach
- Department of Chemistry, Texas
A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United
States
| | - Hashem Amini
- Department of Chemistry, Texas
A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United
States
| | - Nattamai Bhuvanesh
- Department of Chemistry, Texas
A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United
States
| | - John A. Gladysz
- Department of Chemistry, Texas
A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United
States
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Wang MW, Fan W, Li X, Liu Y, Li Z, Jiang W, Wu J, Wang Z. Molecular Carbons: How Far Can We Go? ACS NANO 2023; 17:20734-20752. [PMID: 37889626 DOI: 10.1021/acsnano.3c07970] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/29/2023]
Abstract
The creation and development of carbon nanomaterials promoted material science significantly. Bottom-up synthesis has emerged as an efficient strategy to synthesize atomically precise carbon nanomaterials, namely, molecular carbons, with various sizes and topologies. Different from the properties of the feasibly obtained mixture of carbon nanomaterials, numerous properties of single-component molecular carbons have been discovered owing to their well-defined structures as well as potential applications in various fields. This Perspective introduces recent advances in molecular carbons derived from fullerene, graphene, carbon nanotube, carbyne, graphyne, and Schwarzite carbon acquired with different synthesis strategies. By selecting a variety of representative examples, we elaborate on the relationship between molecular carbons and carbon nanomaterials. We hope these multiple points of view presented may facilitate further advancement in this field.
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Affiliation(s)
- Ming-Wei Wang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Wei Fan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore
| | - Xiaonan Li
- Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Yujian Liu
- Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Zuoyu Li
- Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Wei Jiang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore
| | - Zhaohui Wang
- Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
- Laboratory of Flexible Electronic Technology, Tsinghua University, Beijing 100084, China
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4
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Collins B, Weisbach N, Hampel F, Bhuvanesh N, Gladysz JA. Building Blocks for Molecular Polygons Based on Platinum Vertices and Polyynediyl Edges. Organometallics 2023; 42:2477-2491. [PMID: 38333045 PMCID: PMC10852985 DOI: 10.1021/acs.organomet.2c00573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Indexed: 02/15/2023]
Abstract
Reactions of Cl2P(CH2)3PCl2 and p-MgBrC6H4X (X = a/OMe, b/OtBu, c/tBu, d/SiMe3) give the diphosphines (p-XC6H4)2P(CH2)3P(p-C6H4X)2 (1a-d; 47-66%). Additions of 1a,d to (COD)PtCl2 yield (CH2(CH2P(p-C6H4X)2)2)PtCl2 (2a,d; 62-88%), which upon reaction with butadiyne (2 equiv; HNEt2/cat. CuI) give (CH2(CH2P(p-C6H4X)2)2)Pt((C≡C)2H)2 (3a,d; 34-76%). Alternatively, 3a-d can be accessed from trans-(p-tol3P)2Pt((C≡C)2H)2 and 1a-d (30-87%). Reactions of (p-tol3P)2PtCl2 and H(C≡C)2SiR3 (2 equiv, HNEt2/cat. CuI; R = Me/Et/iPr) give trans-(p-tol3P)2Pt((C≡C)2SiR3)2 (77-95%), and subsequent additions of 1a,b,d yield the corresponding adducts (CH2(CH2P(p-C6H4X)2)2)Pt((C≡C)2SiR3)2 (R/X = Me/OMe, 5a; iPr/OMe, 6a; iPr/OtBu, 6b; iPr/SiMe3, 6d; 52-95%) and (for 5a) a luminescent diplatinum byproduct with trans Pt((C≡C)2SiMe3)2 units. 5a and 6b hydrolyze in the presence of F- to 3a,b (92-93%). Reaction of 2a and 3a (HNEt2/cat. CuI) affords the Pt4C16 polygon ([(CH2(CH2P(p-C6H4OMe)2)2)Pt(C≡C)2]4 as an H2NEt2+ Cl- adduct (66%). The 13C{1H} NMR spectra of 3a-d, 5a, and 6a,b,d feature complex AMXX' (CPtPP') spin systems, and simulations allow J values to be extracted. The crystal structures of 2a, 3a,b,d, 5a, and 6a are determined and analyzed.
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Affiliation(s)
- Brenna
K. Collins
- Department
of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
| | - Nancy Weisbach
- Department
of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
- Institut
für Organische Chemie and Interdisciplinary Center for Molecular
Materials, Friedrich-Alexander-Universität
Erlangen-Nürnberg, Henkestraße 42, Erlangen 91054, Germany
| | - Frank Hampel
- Institut
für Organische Chemie and Interdisciplinary Center for Molecular
Materials, Friedrich-Alexander-Universität
Erlangen-Nürnberg, Henkestraße 42, Erlangen 91054, Germany
| | - Nattamai Bhuvanesh
- Department
of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
| | - John A. Gladysz
- Department
of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States
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Abstract
The formation and study of molecules that model the sp-hybridized carbon allotrope, carbyne, is a challenging field of synthetic physical organic chemistry. The target molecules, oligo- and polyynes, are often the preferred candidates as models for carbyne because they can be formed with monodisperse lengths as well as defined structures. Despite a simple linear structure, the synthesis of polyynes is often far from straightforward, due in large part to a highly conjugated framework that can render both precursors and products highly reactive, i.e., kinetically unstable. The vast majority of polyynes are formed as symmetrical products from terminal alkynes as precursors via an oxidative, acetylenic homocoupling reaction based on the Glaser, Eglinton-Galbraith, and Hay reactions. These reactions are very efficient for the synthesis of shorter polyynes (e.g., hexaynes and octaynes), but yields often drop dramatically as a function of length for longer derivatives, usually starting with the formation of decaynes. The most effective approach to circumvent unstable precursors and products has been through the incorporation of sterically demanding end groups that serve to "protect" the polyyne skeleton. This approach was arguably identified in the early 1950s by Bohlmann and co-workers with the synthesis of tBu-end-capped polyynes. During the next 50 years, a polyyne with 14 contiguous alkyne units remained the longest isolated derivative until 2010, when the record was extended to 22 alkyne units. The record length was broken again in 2020, when a polyyne consisting of 24 alkynes was isolated and characterized. Beyond polyynes, there have been several reports describing the potential synthesis of carbyne, but conclusive characterization and proof of structure have been tenuous. The sole example of synthetic carbyne arises from synthesis within carbon nanotubes, when chains of thousands of sp carbon atoms have been linked to form polydisperse samples of carbyne. Thus, model compounds for carbyne, the polyynes, remain the best means to examine and predict the experimental structure and properties of this carbon allotrope.This Account will discuss the general synthesis of polyynes using homologous series of polyynes with up to 10 alkyne units as examples (decaynes). The limited number of specific syntheses of series with longer polyynes will then be presented and discussed in more detail based on end groups. The monodisperse polyynes produced from these synthetic efforts are then examined toward providing our best extrapolations for the expected characteristics for carbyne based on 13C NMR spectroscopy, UV-vis spectroscopy, X-ray crystallography, and Raman spectroscopy.
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Affiliation(s)
- Yueze Gao
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
| | - Rik R Tykwinski
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada
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Dhindsa JS, Cotterill EL, Buguis FL, Anghel M, Boyle PD, Gilroy JB. Blending the Optical and Redox Properties of Oligoynes and Boron Difluoride Formazanates. Angew Chem Int Ed Engl 2022; 61:e202208502. [DOI: 10.1002/anie.202208502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Jasveer S. Dhindsa
- Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario London ON N6A 5B7 Canada
| | - Erin L. Cotterill
- Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario London ON N6A 5B7 Canada
| | - Francis L. Buguis
- Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario London ON N6A 5B7 Canada
| | - Michael Anghel
- Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario London ON N6A 5B7 Canada
| | - Paul D. Boyle
- Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario London ON N6A 5B7 Canada
| | - Joe B. Gilroy
- Department of Chemistry and the Centre for Advanced Materials and Biomaterials Research (CAMBR) The University of Western Ontario London ON N6A 5B7 Canada
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7
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Leong TX, Collins BK, Dey Baksi S, Mackin RT, Sribnyi A, Burin AL, Gladysz JA, Rubtsov IV. Tracking Energy Transfer across a Platinum Center. J Phys Chem A 2022; 126:4915-4930. [PMID: 35881911 PMCID: PMC9358659 DOI: 10.1021/acs.jpca.2c02017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
Rigid, conjugated alkyne bridges serve as important components
in various transition-metal complexes used for energy conversion,
charge separation, sensing, and molecular electronics. Alkyne stretching
modes have potential for modulating charge separation in donor–bridge–acceptor
compounds. Understanding the rules of energy relaxation and energy
transfer across the metal center in such compounds can help optimize
their electron transfer switching properties. We used relaxation-assisted
two-dimensional infrared spectroscopy to track energy transfer across
metal centers in platinum complexes featuring a triazole-terminated
alkyne ligand of two or six carbons, a perfluorophenyl ligand, and
two tri(p-tolyl)phosphine ligands. Comprehensive
analyses of waiting-time dynamics for numerous cross and diagonal
peaks were performed, focusing on coherent oscillation, energy transfer,
and cooling parameters. These observables augmented with density functional
theory computations of vibrational frequencies and anharmonic force
constants enabled identification of different functional groups of
the compounds. Computations of vibrational relaxation pathways and
mode couplings were performed, and two regimes of intramolecular energy
redistribution are described. One involves energy transfer between
ligands via high-frequency modes; the transfer is efficient only if
the modes involved are delocalized over both ligands. The energy transport
pathways between the ligands are identified. Another regime involves
redistribution via low-frequency delocalized modes, which does not
lead to interligand energy transport.
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Affiliation(s)
- Tammy X Leong
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Brenna K Collins
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Sourajit Dey Baksi
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Robert T Mackin
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Artem Sribnyi
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Alexander L Burin
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - John A Gladysz
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Igor V Rubtsov
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
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Dhindsa JS, Cotterrill EL, Buguis FL, Anghel M, Boyle PD, Gilroy JB. Blending the Optical and Redox Properties of Oligoynes and Boron. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202208502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jasveer S Dhindsa
- University of Western Ontario: Western University Department of Chemistry CANADA
| | - Erin L. Cotterrill
- University of Western Ontario: Western University Department of Chemistry CANADA
| | - Francis L. Buguis
- University of Western Ontario: Western University Department of Chemistry CANADA
| | - Michael Anghel
- University of Western Ontario: Western University Department of Chemistry CANADA
| | - Paul D. Boyle
- University of Western Ontario: Western University Department of Chemistry CANADA
| | - Joe B. Gilroy
- The University of Western Ontario Department of Chemistry 1151 Richmond St. N. N6A 5B7 London CANADA
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10
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Amini H, Weisbach N, Gauthier S, Kuhn H, Bhuvanesh N, Hampel F, Reibenspies JH, Gladysz JA. Trapping of Terminal Platinapolyynes by Copper(I) Catalyzed Click Cycloadditions; Probes of Labile Intermediates in Syntheses of Complexes with Extended sp Carbon Chains, and Crystallographic Studies. Chemistry 2021; 27:12619-12634. [PMID: 34101914 DOI: 10.1002/chem.202101725] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Indexed: 11/07/2022]
Abstract
The silylated hexatriynyl complex trans-(C6 F5 )(p-tol3 P)2 Pt(C≡C)3 SiEt3 (PtC6 TES) is converted in situ to PtC6 H (wet n-Bu4 N+ F- , THF) and cross coupled with the diyne H(C≡C)2 SiEt3 (HC4 TES; CuCl/TMEDA, O2 ) to give PtC10 TES (71 %). This sequence is repeated twice to afford PtC14 TES (65 %) and then PtC18 TES (27 %). An analogous series of reactions starting with PtC8 TES gives PtC12 TES (60 %), then PtC16 TES (43 %), and then PtC20 TES (17 %). Similar cross couplings with H(C≡C)2 Si(i-Pr)3 (HC4 TIPS) give PtC12 TIPS (68 %), PtC14 TIPS (68 %), and PtC16 TIPS (34 %). The trialkylsilyl species (up to PtC18 TES) are converted to 3+2 "click" cycloadducts or 1,4-disubstituted 1,2,3-triazoles trans-(C6 F5 )(p-tol3 P)2 Pt(C≡C)n-1 C=CHN(CH2 C6 H5 )N=N (29-92 % after workups). The most general procedure involves generating the terminal polyynes PtCx H (wet n-Bu4 N+ F- , THF) in the presence of benzyl azide in DMF and aqueous CuSO4 /ascorbic acid. All of the preceding complexes are crystallographically characterized and the structural and spectroscopic properties analyzed as a function of chain length. Two pseudopolymorphs of PtC20 TES are obtained, both of which feature molecules with parallel sp carbon chains in a pairwise head/tail packing motif with extensive sp/sp van der Waals contacts.
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Affiliation(s)
- Hashem Amini
- Department of Chemistry, Texas A&M University P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Nancy Weisbach
- Department of Chemistry, Texas A&M University P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Sébastien Gauthier
- Department of Chemistry, Texas A&M University P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Helene Kuhn
- Institut für Organische Chemie and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestraße 42, 91054, Erlangen, Germany
| | - Nattamai Bhuvanesh
- Department of Chemistry, Texas A&M University P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Frank Hampel
- Institut für Organische Chemie and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestraße 42, 91054, Erlangen, Germany
| | - Joseph H Reibenspies
- Department of Chemistry, Texas A&M University P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - John A Gladysz
- Department of Chemistry, Texas A&M University P.O. Box 30012, College Station, Texas, 77842-3012, USA
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Collins BK, Clough Mastry M, Ehnbom A, Bhuvanesh N, Hall MB, Gladysz JA. Macrocyclic Complexes Derived from Four cis-L 2 Pt Corners and Four Butadiynediyl Linkers; Syntheses, Electronic Structures, and Square versus Skew Rhombus Geometries. Chemistry 2021; 27:10021-10039. [PMID: 34114260 DOI: 10.1002/chem.202100305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Indexed: 11/11/2022]
Abstract
The dialkyl malonate derived 1,3-diphosphines R2 C(CH2 PPh2 )2 (R=a, Me; b, Et; c, n-Bu; d, n-Dec; e, Bn; f, p-tolCH2 ) are combined with (p-tol3 P)2 PtCl2 or trans-(p-tol3 P)2 Pt((C≡C)2 H)2 to give the chelates cis-(R2 C(CH2 PPh2 )2 )PtCl2 (2 a-f, 94-69 %) or cis-(R2 C(CH2 PPh2 )2 )Pt((C≡C)2 H)2 (3 a-f, 97-54 %). Complexes 3 a-d are also available from 2 a-d and excess 1,3-butadiyne in the presence of CuI (cat.) and excess HNEt2 (87-65 %). Under similar conditions, 2 and 3 react to give the title compounds [(R2 C(CH2 PPh2 )2 )[Pt(C≡C)2 ]4 (4 a-f; 89-14 % (64 % avg)), from which ammonium salts such as the co-product [H2 NEt2 ]+ Cl- are challenging to remove. Crystal structures of 4 a,b show skew rhombus as opposed to square Pt4 geometries. The NMR and IR properties of 4 a-f are similar to those of mono- or diplatinum model compounds. However, cyclic voltammetry gives only irreversible oxidations. As compared to mono-platinum or Pt(C≡C)2 Pt species, the UV-visible spectra show much more intense and red-shifted bands. Time dependent DFT calculations define the transitions and principal orbitals involved. Electrostatic potential surface maps reveal strongly negative Pt4 C16 cores that likely facilitate ammonium cation binding. Analogous electronic properties of Pt3 C12 and Pt5 C20 homologs and selected equilibria are explored computationally.
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Affiliation(s)
- Brenna K Collins
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Melissa Clough Mastry
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA.,Present address: BASF, Refinery Catalysts, 25 Middlesex-Essex Tpk., Iselin, NJ, 08830, USA
| | - Andreas Ehnbom
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Nattamai Bhuvanesh
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Michael B Hall
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - John A Gladysz
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
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The loss of endgroup effects in long pyridyl-endcapped oligoynes on the way to carbyne. Nat Chem 2020; 12:1143-1149. [DOI: 10.1038/s41557-020-0550-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 08/07/2020] [Indexed: 11/09/2022]
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Is It Conjugated or Not? The Theoretical and Experimental Electron Density Map of Bonding in p-CH3CH2COC6H4-C≡C-C≡C-p-C6H4COCH3CH2. Molecules 2020; 25:molecules25194388. [PMID: 32987740 PMCID: PMC7583911 DOI: 10.3390/molecules25194388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/19/2020] [Accepted: 09/19/2020] [Indexed: 11/17/2022] Open
Abstract
The electron density of p-CH3CH2COC6H4-C≡CC≡C-p-C6H4COCH3CH2 has been investigated on the basis of single-crystal X-ray diffraction data collected to high resolution at 100 K and from theoretical calculations. An analysis of the X-ray data of the diyne showed interesting “liquidity” of electron distribution along the carbon chain compared to 1,2-diphenylacetylene. These findings are compatible with the results of topological analysis of Electron Localization Function (ELF), which has also revealed a larger (than expected) concentration of the electron density at the single bonds. Both methods indicate a clear π-type or “banana” character of a single bond and a significant distortion from the typical conjugated structure of the bonding in the diyne with a small contribution of cumulenic structures.
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Amini H, Baranová Z, Weisbach N, Gauthier S, Bhuvanesh N, Reibenspies JH, Gladysz JA. Syntheses, Structures, and Spectroscopic Properties of 1,10-Phenanthroline-Based Macrocycles Threaded by PtC 8 Pt, PtC 12 Pt, and PtC 16 Pt Axles: Metal-Capped Rotaxanes as Insulated Molecular Wires. Chemistry 2019; 25:15896-15914. [PMID: 31596000 DOI: 10.1002/chem.201903927] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/01/2019] [Indexed: 11/05/2022]
Abstract
The platinum polyynyl complexes trans-(C6 F5 )(p-tol3 P)2 Pt(C≡C)n/2 H undergo oxidative homocoupling (O2 , CuCl/TMEDA) to diplatinum polyynediyl complexes trans, trans-(C6 F5 )(p-tol3 P)2 Pt(C≡C)n Pt(Pp-tol3 )2 (C6 F5 ) (n=4, 2; 6, 5; 8, 8; 92-97 %) as reported previously. When related reactions are conducted in the presence of CuI adducts of the 1,10-phenanthroline-based macrocycles 2,9-(1,10-phenanthrolinediyl)(p-C6 H4 O(CH2 )6 O)2 (1,3-C6 H4 ) (10, 33-membered) or 2,9-(1,10-phenanthrolinediyl)(p-C6 H4 O(CH2 )6 O)2 (2,7-naphthalenediyl) (11, 35-membered), excess K2 CO3 , and I2 (oxidant), rotaxanes are isolated that feature a Pt(C≡C)n Pt axle that has been threaded through the macrocycle (2⋅10, 9 %; 5⋅10, 41 %; 5⋅11, 28 %; 8⋅10, 12 %; 8⋅11, 9 %). Their crystal structures are determined and analyzed in detail, particularly with respect to geometric perturbations and the degree of steric sp carbon chain insulation. NMR spectra show a number of shielding effects. UV/Vis spectra do not indicate significant electronic interactions between the Pt(C≡C)n Pt axles and macrocycles, although cyclic voltammetry data suggest rapid reactions following oxidation.
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Affiliation(s)
- Hashem Amini
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Zuzana Baranová
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Nancy Weisbach
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Sébastien Gauthier
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Nattamai Bhuvanesh
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - Joseph H Reibenspies
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
| | - John A Gladysz
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas, 77842-3012, USA
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