Petostruka veza

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

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.

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

^ Steve Ritter (26. 9. 2005). „Quintuple Bond Makes Its Debut First stable molecule with fivefold metal-metal bonding is synthesized”. Chemical & Engineering News. стр. 9.
^ Nguyen, Tailuan; Sutton, Andrew D.; Brynda, Marcin; Fettinger, James C.; Long, Gary J.; Power, Philip P. (2005). „Synthesis of a Stable Compound with Fivefold Bonding Between Two Chromium(I) Centers”. Science. 310 (5749): 844—847. Bibcode:2005Sci...310..844N. PMID 16179432. doi:10.1126/science.1116789. Support info}-
^ [1] Архивирано на веб-сајту Wayback Machine (19. јануар 2020) 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
^ La Macchia, Giovanni; Gagliardi, Laura; Power, Philip P.; Brynda, Marcin (2008). „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”. Journal of the American Chemical Society. 130 (15): 5104—5114. Bibcode:2008JAChS.130.5104L. PMID 18335988. doi:10.1021/ja0771890.
^ Merino, Gabriel; Donald, Kelling J.; d'Acchioli, Jason S.; Hoffmann, Roald (2007). „The Many Ways to Have a Quintuple Bond”. Journal of the American Chemical Society. 129 (49): 15295—15302. Bibcode:2007JAChS.12915295M. PMID 18004851. doi:10.1021/ja075454b.

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Šestostruka veza

[1] Steve Ritter (26. 9. 2005). „Quintuple Bond Makes Its Debut First stable molecule with fivefold metal-metal bonding is synthesized”. Chemical & Engineering News. стр. 9.

[2] Nguyen, Tailuan; Sutton, Andrew D.; Brynda, Marcin; Fettinger, James C.; Long, Gary J.; Power, Philip P. (2005). „Synthesis of a Stable Compound with Fivefold Bonding Between Two Chromium(I) Centers”. Science. 310 (5749): 844—847. Bibcode:2005Sci...310..844N. PMID 16179432. doi:10.1126/science.1116789. Support info}-

[3] [1] Архивирано на веб-сајту Wayback Machine (19. јануар 2020) 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] La Macchia, Giovanni; Gagliardi, Laura; Power, Philip P.; Brynda, Marcin (2008). „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”. Journal of the American Chemical Society. 130 (15): 5104—5114. Bibcode:2008JAChS.130.5104L. PMID 18335988. doi:10.1021/ja0771890.

[5] Merino, Gabriel; Donald, Kelling J.; d'Acchioli, Jason S.; Hoffmann, Roald (2007). „The Many Ways to Have a Quintuple Bond”. Journal of the American Chemical Society. 129 (49): 15295—15302. Bibcode:2007JAChS.12915295M. PMID 18004851. doi:10.1021/ja075454b.

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