Petostruka veza

Petostruka veza u hemiji je neobičan tip hemijske veze, koja je prvi put opisana 2005. za jedno dihromno jedinjenje. Jednostruke, dvostruke, i trostruke veze su uobičajene u hemiji. Četvorostruke veze su ređe, mada su prisutne kod jedinjenja hroma, molibdena, volframa i renijuma, npr. [Mo₂Cl₈]⁴⁻ i [Re₂Cl₈]²⁻. U petostrukoj vezi, deset elektrona učestvuje u vezivanju dva metalna centra. One su alocirane kao σ²π⁴δ⁴.

Struktura [CrC₆H₃-2,6-(C₆H₃-2,6-(CHMe₂)₂)₂]₂

U nekim slučajevima veza visokog reda između atoma metala, metal-metal vezivanje je posredovano ligandima koji vezuju dva metalna centra i umanjuju interatomsko rastojanje. Nasuprot tome, hromni dimer sa petostrukom vezom je stabilizovan glomaznim terfenil (2,6-[(2,6-diizopropil)fenil]fenil) ligandima. Kompleks je stabilan do 200 °C.^[1]^[2] Hrom-hrom petostruka veza je bila analizovana putem multireferentnih ab-initio i DFT methoda,^[3] koji su takođe korišteni za određivanje uloge terfenilnih liganda. Pokazano da bočne aril grupe formiraju veoma slabe interakcije sa atomima hroma, što uzrokuje malo slabljenje petostruke veze.^[4] Jedna teoretska studija iz 2007. je identifikovala dva globalna minimuma kod petostruko vezanih RMMR jedinjenja.^[5]

Reference

↑ Quintuple Bond Makes Its Debut First stable molecule with fivefold metal-metal bonding is synthesized Steve Ritter Chemical & Engineering News 26 September 2005 Volume 83, Number 39
↑ Synthesis of a Stable Compound with Fivefold Bonding Between Two Chromium(I) Centers Tailuan Nguyen, Andrew D. Sutton, Marcin Brynda, James C. Fettinger, Gary J. Long, and Philip P. Power Published online 22 September 2005; 10.1126/science.1116789 Support info
↑ [https://web.archive.org/web/20200119203602/http://www3.interscience.wiley.com/cgi-bin/fulltext/112604898/PDFSTART Arhivirano 2020-01-19 na Wayback Machine-u Quantum Chemical Study of the Quintuple Bond between Two Chromium Centers in [PhCrCrPh]: trans-Bent versus Linear Geometry] Marcin Brynda, Laura Gagliardi, Per-Olof Widmark, Philip P. Power, Björn O. Roos Angewandte Chemie International Edition Published online 3 May 2006
↑ Large Differences in Secondary Metal−Arene Interactions in the Transition-Metal Dimers ArMMAr (Ar = Terphenyl; M = Cr, Fe, or Co): Implications for Cr−Cr Quintuple Bonding Giovanni La Macchia, Laura Gagliardi, Philip P. Power, and Marcin Brynda J. Am. Chem. Soc. 2008 ASAP Article DOI:10.1021/ja0771890
↑ The Many Ways To Have a Quintuple Bond Gabriel Merino, Kelling J. Donald, Jason S. D’Acchioli, and Roald Hoffmann, J. Am. Chem. Soc. 2007 ASAP Article DOI:10.1021/ja075454b

Povezano

Šestostruka veza

[1] Quintuple Bond Makes Its Debut First stable molecule with fivefold metal-metal bonding is synthesized Steve Ritter Chemical & Engineering News 26 September 2005 Volume 83, Number 39

[2] Synthesis of a Stable Compound with Fivefold Bonding Between Two Chromium(I) Centers Tailuan Nguyen, Andrew D. Sutton, Marcin Brynda, James C. Fettinger, Gary J. Long, and Philip P. Power Published online 22 September 2005; 10.1126/science.1116789 Support info

[3] [https://web.archive.org/web/20200119203602/http://www3.interscience.wiley.com/cgi-bin/fulltext/112604898/PDFSTART Arhivirano 2020-01-19 na Wayback Machine-u Quantum Chemical Study of the Quintuple Bond between Two Chromium Centers in [PhCrCrPh]: trans-Bent versus Linear Geometry] Marcin Brynda, Laura Gagliardi, Per-Olof Widmark, Philip P. Power, Björn O. Roos Angewandte Chemie International Edition Published online 3 May 2006

[4] Large Differences in Secondary Metal−Arene Interactions in the Transition-Metal Dimers ArMMAr (Ar = Terphenyl; M = Cr, Fe, or Co): Implications for Cr−Cr Quintuple Bonding Giovanni La Macchia, Laura Gagliardi, Philip P. Power, and Marcin Brynda J. Am. Chem. Soc. 2008 ASAP Article DOI:10.1021/ja0771890

[5] The Many Ways To Have a Quintuple Bond Gabriel Merino, Kelling J. Donald, Jason S. D’Acchioli, and Roald Hoffmann, J. Am. Chem. Soc. 2007 ASAP Article DOI:10.1021/ja075454b

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