Skip to main content
SpringerLink
Log in

Redox-Active Guanidines and Guanidinate-Substituted Diboranes

  • Chapter
  • First Online:
Guanidines as Reagents and Catalysts II

Part of the book series: Topics in Heterocyclic Chemistry ((TOPICS,volume 51))

Abstract

Guanidino groups and guanidinate substituents are used to stabilise positive charges, both through mesomeric and through inductive effects. The interplay between several guanidino groups is employed to create redox-active compounds. One realisation concept leads to guanidino-functionalised aromatic compounds (GFAs), which comprise aromatic systems substituted with several guanidino groups and constitute a relatively new class of strong organic electron donors as well as redox-active ligands. Some properties of these compounds and applications are presented, e.g. photochemical reductive C–C coupling, redox switches and stabilisation of polyanions. In addition, we allude to dinuclear copper complexes of bridging GFA ligands with several oxidation states of copper and the GFA ligand. In a second concept, two guanidinyl groups are connected, leading to bisguanidines which are generally termed urea azines. They could be oxidised in two separated one-electron steps. GFAs and bisguanidines are compared with other organic electron donors, and a relationship is established between the (gas-phase) adiabatic ionisation energy and the redox potential in solution. Lewis acid-base adducts between boranes and bicyclic guanidines could be subjected to dehydrocoupling reactions, leading to new sp3–sp3-hybridised diboranes of special reactivity. Their coordination chemistry and oxidative insertion reactions into the B–B bond are discussed. The electron-rich bridging guanidinate substituents allow for the synthesis of unprecedented cationic boron hydride compounds.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution
Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 169.00
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 219.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD 219.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Notes

  1. 1.

    Attempts to synthesise this compound were so far unsuccessful. The standard route (“activation” of the urea by reaction with oxalyl chloride and subsequent reaction with hydrazine) fails due to the reduced electrophilicity of the imidazolium salt (“activated urea”). See the Supporting Information in Herrmann et al. [73].

Abbreviations

9-BBN:

9-Borabicyclo[3.3.1]nonane

COSMO:

Conductor-like screening model

CV:

Cyclic voltammetry

Fc/Fc+ :

Ferrocene/Ferrocenium

GFA:

Redox-active guanidino-functionalised aromatic compound

hppH:

1,3,4,6,7,8-Hexahydro-2H-pyrimido[1,2-a]pyrimidine. The compound is also known as triazabicyclodecene (1,5,7-triazabicyclo[4.4.0]dec-5-ene or TBD)

Htbn:

1,5,7-Triazabicyclo[4.3.0]non-6-ene

Htbo:

1,4,6-Triazabicyclo[3.3.0]oct-4-ene

TCNQ:

Tetracyanoquinodimethane

TDAE:

Tetrakis(dimethylamino)ethylene

References

  1. Edelmann FT (2008) Advances in the coordination chemistry of amidinate and guanidinate ligands. Adv Organomet Chem 57:183–352

    Article  CAS  Google Scholar 

  2. Edelmann FT (1994) N-silylated benzamidines: versatile building blocks in main group and coordination chemistry. Coord Chem Rev 137:403–481

    Article  Google Scholar 

  3. Barker J, Kilner M (1994) The coordination chemistry of the amidine ligand. Coord Chem Rev 133:219–300

    Article  CAS  Google Scholar 

  4. Bailey PJ, Price S (2001) The coordination chemistry of guanidines and guanidinates. Coord Chem Rev 214:91–141

    Article  CAS  Google Scholar 

  5. Herres-Pawlis S (2009) Außergewöhnliche Donoren und synthetische Vielfalt: Guanidine. Nachr Chem 57:20–23

    Article  CAS  Google Scholar 

  6. Coles MP (2006) Application of neutral amidines and guanidines in coordination chemistry. Dalton Trans 985–1001

    Google Scholar 

  7. Coles MP (2009) Bicyclic guanidines, guanidinates and guanidium salts: wide ranging applications from a simple family of molecules. Chem Commun 3659–3676

    Google Scholar 

  8. Himmel H-J (2011) Hydrogenation and dehydrogenation of dinuclear boron and gallium hydrides: quantum chemical calculations and experiments. In: Comba P (ed) Modeling of molecular properties. Wiley-VCH, Weinheim

    Google Scholar 

  9. Jones C (2010) Bulky guanidinates for the stabilization of low oxidation state metallacycles. Coord Chem Rev 254:1273–1289

    Article  CAS  Google Scholar 

  10. Edelmann FT (2013) Recent progress in the chemistry of metal amidinates and guanidinates: syntheses, catalysis and materials. Adv Organomet Chem 61:55–374

    Article  CAS  Google Scholar 

  11. Würtele C, Gaoutchenova E, Harms K, Holthausen MC, Sundermeyer J, Schindler S (2006) Crystallographic characterization of a synthetic 1:1 end-on copper dioxygen adduct complex. Angew Chem 118:3951–3954, Angew Chem Int Ed 45:3867–3869

    Article  Google Scholar 

  12. Maiti D, Lee D-H, Gaoutchenova K, Würtele C, Holthausen MC, Sarjeant AAN, Sundermeyer J, Schindler S, Karlin KD (2007) Reactions of a copper (II) superoxo complex lead to C-H and O-H substrate oxygenation: modeling copper monooxygenase C-H hydroxynation. Angew Chem 120:88–91, Angew Chem Int Ed 47:82–85

    Article  Google Scholar 

  13. Lanci MP, Smirnov VV, Cramer CJ, Gauchenova EV, Sundermeyer J, Roth JP (2007) Isotopic probing of molecular oxygen activation and copper(I) sites. J Am Chem Soc 129(47):14697–14709

    Article  CAS  Google Scholar 

  14. Maiti D, Lee D-H, Gaoutchenova K, Würtele C, Holthausen MC, Sarjeant AAN, Sundermeyer J, Schindler S, Karlin KD (2008) Coordination chemistry and reactivity of a cubric hyperoxide species featuring a proximal H-bonding substituent. Angew Chem 120:88–91, Angew Chem Int Ed 47:82–85

    Article  Google Scholar 

  15. Peterson RL, Ginsbach JW, Cowley RE, Qayyum MF, Himes RA, Siegler MA, Moore CD, Hedman B, Hodgson KO, Fukuzumi S, Solomon EI, Karlin KD (2013) Stepwise protonation and electron transfer reduction of a primary copper-dioxygen adduct. J Am Chem Soc 135(44):16454–16467

    Article  CAS  Google Scholar 

  16. Saracini C, Liakos DG, Zapata Rivera JE, Neese F, Meyer GJ, Karlin KD (2014) Excitation wavelength dependent O2 release from copper(II) superoxide compounds: laser flash-photolysis experiments and theoretical studies. J Am Chem Soc 136(4):1260–1263

    Article  CAS  Google Scholar 

  17. Börner J, Flörke U, Huber K, Döring A, Kuckling D, Herres-Pawlis S (2009) New catalysts for the ring-opening polymerisation of D, L-lactide. Chem Eur J 15:2362–2376

    Article  Google Scholar 

  18. Börner J, dos Santos Vieira I, Pawlis A, Doering A, Kuckling D, Herres-Pawlis S (2011) Mechanism of the living lactide polymerisation mediated by robust zinc guanidine complexes. Chem Eur J 17:4507–4512

    Article  Google Scholar 

  19. Börner J, dos Santos Vieira I, Jones MD, Döring A, Kuckling D, Flörke U, Herres-Pawlis S (2011) Zinc complexes with guanidine-pyridine hybrid-ligands – guanidine effect and catalytic activity. Eur J Inorg Chem 4441–4456

    Google Scholar 

  20. dos Santos VI, Herres-Pawlis S (2012) Lactide polymerisation with complexes of neutral N-donors – new strategies for robust catalysts. Eur J Inorg Chem 5:765–774

    Article  Google Scholar 

  21. dos Santos Vieira I, Herres-Pawlis S (2012) Novel guanidine-quinoline hybrid ligands and the application of their zinc complexes in lactide polymerisation. Z Naturforsch B 67:320–330

    Article  Google Scholar 

  22. Maronna A, Hübner O, Enders M, Kaifer E, Himmel H-J (2013) Bisguanidines with biphenyl, binaphthyl and bipyridyl cores: proton sponge properties and coordination chemistry. Chem Eur J 19:8958–8977

    Article  CAS  Google Scholar 

  23. Green SP, Jones C, Stasch A (2007) Stable magnesium(I) compounds with Mg-Mg bonds. Science 318:1754–1757

    Article  CAS  Google Scholar 

  24. Westerhausen M (2008) Molecular magnesium(I) compounds: from curiosity to kudos. Angew Chem 120:2215–2217, Angew Chem Int Ed 47:2185–2187

    Article  Google Scholar 

  25. Cotton FA, Matonic JH, Murillo CA (1997) A new type of divalent niobium compound: the first Nb-Nb triple bond in a tetragonal lantern environment. J Am Chem Soc 119(33):7889–7890

    Article  CAS  Google Scholar 

  26. Bear JL, Li Y, Han B, Kadish KM (1996) Synthesis, molecular structure and electrochemistry of a paramagnetic diruthenium(III) complex. Characterisation or Ru2(hpp)4Cl2, where hpp is the 1,3,4,6,8-hexahydro 2H-pyrimido[1,2-α]pyrimidinate ion. Inorg Chem 35(5):1395–1398

    Article  CAS  Google Scholar 

  27. Clérac R, Cotton FA, Daniels LM, Donahue JP, Murillo CA, Timmons DJ (2000) Completion of the series of M2(hpp)4Cl2 compounds from W to Pt: the W, Pt and Os compounds. Inorg Chem 39:2581–2584

    Article  Google Scholar 

  28. Cotton FA, Murillo CA, Wang X, Wilkinson CC (2003) Structural studies of nickel complexes and the unsymmetrical ligand N-phenyl-N-(2-pyridyl)formamidinate. Inorg Chim Acta 351:191–200

    Article  CAS  Google Scholar 

  29. Day BM, Mansfield NE, Coles MP, Hitchcock PB (2011) Bicyclic guanidine compounds of magnesium and their activity as pre-catalysts in the Tishchenko reaction. Chem Commun 47:4995–4997

    Article  CAS  Google Scholar 

  30. Schwesinger R (1990) Organophosphorus reagents: a practical approach in chemistry. Nachr Chem Tech Lab 38:1214–1226

    Article  CAS  Google Scholar 

  31. Ishikawa T (ed) (2009) Superbases for organic synthesis: guanidines, amidines and phosphazenes and related organocatalysts. Wiley, Chichester

    Google Scholar 

  32. Alder RW, Bowman PS, Steele WRS, Winterman DR (1968) The remarkable basicity of 1,8-bis(dimethylamino)naphthalene. J Chem Soc Chem Commun 723–724

    Google Scholar 

  33. Maksić ZB, Kovačević B (2000) Absolute proton affinity of some polyguanides. J Org Chem 65:3303–3309

    Article  Google Scholar 

  34. Raab V, Kipke J, Gschwind RM, Sundermeyer J (2002) A new, superbasic and kinetically active proton sponge. Chem Eur J 8:1682–1693

    Article  CAS  Google Scholar 

  35. Coles MP, Aragón-Sáez PJ, Oakley SH, Hitchcock PB, Davidson MG, Maksić ZB, Vianello R, Leito I, Kaljurand I, Apperley DC (2009) Superbasicity of a bis-guanidino compound with a flexible linker: a theoretical and experimental study. J Am Chem Soc 131:16858–16868

    Article  CAS  Google Scholar 

  36. Kovačević B, Maksić ZB (2002) Relationships between basicity, structure, chemical shift and the charge distribution in resonance stabilized imioamines. Chem Eur J 8:1694–1702

    Article  Google Scholar 

  37. Raab V, Harms K, Sundermeyer J, Kovačević B, Maksić ZB (2003) 1,8-Bis(dimethylethyleneguanidino) naphthalene, DMEGN: tailoring the basicity of bisguanidine proton sponges by experiment and theory. J Org Chem 68:8790–8797

    Article  CAS  Google Scholar 

  38. Singh A, Ganguly B (2008) Strategic design of small and versatile bicyclic organic superbases: a density functional study. New J Chem 32:210–213

    Article  CAS  Google Scholar 

  39. Wild U, Hübner O, Maronna A, Enders M, Kaifer E, Wadepohl H, Himmel H-J (2008) The first metal complexes of the proton sponge 1,8-bis(N,N,N′,N′-tetramethylguanidino)naphthalene: synthesis and properties. Eur J Inorg Chem 4440–4447

    Google Scholar 

  40. Ishikawa T (2009) Superbases for organic synthesis. Wiley, Chichester

    Book  Google Scholar 

  41. Broggi J, Terme T, Vanelle P (2014) Organic electron donors as powerful single electron reducing agents in organic synthesis. Angew Chem 126:392–423, Angew Chem Int Ed 53:384–413

    Article  Google Scholar 

  42. Pruett RL, Barr JT, Rapp KE, Bahner CT, Gibson JD, Lafferty RH (1950) Reactions of polyfluoro olefins. II. Reactions with primary and secondary amines. J Am Chem Soc 72:3646–3650

    Article  CAS  Google Scholar 

  43. Fox JR, Foxman BM, Guarrera D, Miller JS, Calabrese JC, Reis AH Jr (1996) Characterization of two novel TCNQ and TCNE 1:1 and 1:2 salts of the tetrakis (dimethylamino)ethylene dication [{(CH3)2N}2C-C{N(CH3)2}2]2+. J Mater Chem 6:1627–1631

    Article  CAS  Google Scholar 

  44. Burkholder C, Dolbier WR Jr, Médebielle M (1998) Nucleophilic trifluoromethylation using trifluoromethyl iodide. A new and simple alternative for the trifluoromethylation of aldehydes and ketones. J Org Chem 63:5385–5394

    Article  CAS  Google Scholar 

  45. Bock H, Jaculi D (1984) Oxidation reactions with “naked” permanganate ions under aprotic conditions. Angew Chem 96:298–299, Angew Chem Int Ed 23:305–307

    Article  CAS  Google Scholar 

  46. Eberle B, Hübner O, Ziesak A, Kaifer E, Himmel H-J (2015) What makes a strong organic electron donor (or acceptor)? Chem Eur J 21:8578–8590. doi:10.1002/chem.201406597

  47. Wanzlick H-W, Schikora E (1960) Ein neuer Zugang zur Carben-Chemie. Angew Chem 72(16):494

    Article  CAS  Google Scholar 

  48. Wiberg N (1968) Photochemical cyclodehydrogenations in the indole series. Angew Chem 80:466–481, Angew Chem Int Ed 7:766–779

    Article  Google Scholar 

  49. Taton TA, Chen PA (1996) A stable tetraazafulvalene. Angew Chem 108:1098–1100, Angew Chem Int Ed 35:1011–1013

    Article  Google Scholar 

  50. Murphy JA, Zhou SZ, Thomson DW, Schoenebeck F, Mahesh M, Park SR, Tuttle T, Berlouis LEA (2007) The generation of aryl anions by double electron transfer to aryl iodides from a neutral ground state organic super-electron donor. Angew Chem 119:5270–5275, Angew Chem Int Ed 46:5178–5183

    Article  Google Scholar 

  51. Doni E, Murphy JA (2014) Evolution of neutral organic super-electron-donors and their applications. Chem Commun 50:6073–6087

    Article  CAS  Google Scholar 

  52. Peters A, Kaifer E, Himmel H-J (2008) 1,2,4,5-tetrakis(tetramethylguanidine) benzene: synthesis and properties of a new molecular electron donor. Eur J Org Chem 5907–5914

    Google Scholar 

  53. Himmel H-J (2013) Guanidinyl-functionalized aromatic compounds (GFAs) – charge and spin density studies as starting points for the development of a new class of redox-active ligands. Z Anorg Allg Chem 639:1940–1952

    Article  CAS  Google Scholar 

  54. Peters A, Herrmann H, Magg M, Kaifer E, Himmel, H-J (2012) Tuning the properties of guanidino-functionalized aromatic electron donors by substitution: experiment and theory. Eur J Inorg Chem 1620–1631

    Google Scholar 

  55. Farwaha HS, Buchr G, Murphy JA (2013) A novel neutral organic electronic with record half-wave potential. Org Biomol Chem 11:8073–8081

    Article  CAS  Google Scholar 

  56. Vitske V, König C, Kaifer E, Hübner O, Himmel H-J (2010) Syntheses of the first coordination compounds of the new strong molecular electron donor and double proton sponge 1,4,5,8-tetrakis(tetra-methylguanidino)naphthalene. Eur J Inorg Chem 115–126

    Google Scholar 

  57. Vitske V, Roquette P, Leingang S, Adam C, Kaifer E, Wadepohl H, Himmel H-J (2011) Donor-acceptor couples and late transition metal complexes of oxidation-labile 1,4,5,8-tetrakis(guanidino)naphthalene superbases. Eur J Inorg Chem 1593–1604

    Google Scholar 

  58. Maronna A, Bindewald E, Kaifer E, Wadepohl H, Himmel H-J (2011) Synthesis and characterization of novel guanidine ligands featuring a biphenyl or binaphthyl backbone. Eur J Inorg Chem 1302–1314

    Google Scholar 

  59. Stang S, Lebkücher A, Walter P, Kaifer E, Himmel H-J (2012) Redox-active guanidine ligands with pyridine and p-benzoquinone backbones. Eur J Inorg Chem 4833–4845

    Google Scholar 

  60. Bindewald E, Lorenz R, Hübner O, Brox D, Herten D-P, Kaifer E, Himmel H-J (2015) Tetraguanidino-functionalized phenazine and fluorene dyes: synthesis, optical properties and metal coordination. Dalton Trans 44:3467–3485

    Article  CAS  Google Scholar 

  61. Vitske V, Herrmann H, Enders M, Kaifer E, Himmel H-J (2012) The wrapping up of an organic reducing reagent in a cationic boron complex and its use for the synthesis of polyhalide monoanionic networks. Chem Eur J 18:14108–14116

    Article  CAS  Google Scholar 

  62. Herrmann H, Ziesak A, Wild U, Leingang S, Schrempp D, Wagner N, Beck J, Kaifer E, Wadepohl H, Himmel H-J (2014) Tetracyanoquinodimethane (TCNQ) reduction by complexed guanidinyl-functionalized aromatic compounds (GFAs). ChemPhysChem 15:351–365

    Article  CAS  Google Scholar 

  63. Stang S, Kaifer E, Himmel H-J (2014) Metal-free C-C coupling reactions with tetraguanidino-functionalized pyridines and light. Chem Eur J 20:5288–5297

    Article  CAS  Google Scholar 

  64. Emeljanenko D, Peters A, Vitske V, Kaifer E, Himmel H-J (2010) Guanidine-functionalized aromatic electron donors at work: competing hydrogen and electron transfer reactions in the course of the synthesis of gold acetylide complexes. Eur J Inorg Chem 4783–4789

    Google Scholar 

  65. Wild U, Neuhäuser C, Wiesner S, Kaifer E, Wadepohl H, Himmel H-J (2014) Redox-controlled hydrogen bonding: turning a superbase into a strong hydrogen-bond donor. Chem Eur J 20:5914–5925

    Article  CAS  Google Scholar 

  66. Emeljanenko D, Peters A, Wagner N, Beck J, Kaifer E, Himmel H-J (2010) Successive ligand and metal oxidation: redox reactions involving binuclear Cu(I) complexes of chelating guanidine ligands. Eur J Inorg Chem 1839–1846

    Google Scholar 

  67. Trumm C, Hübner O, Walter P, Leingang S, Wild U, Kaifer E, Eberle B, Himmel H-J (2014) One-versus two-electron oxidation of complexed guanidino-functionalized aromatic compounds. Eur J Inorg Chem 6039–6050

    Google Scholar 

  68. Trumm C, Kaifer E, Hübner O, Himmel H-J (2010) Trapped in a complex: the 1,2,4,5-tetrakis(tetramethyl-guanidino)benzene radical cation (ttmgb+·) featuring a bisallylic structure. Eur J Inorg Chem 3102–3108

    Google Scholar 

  69. Peters A, Trumm C, Reinmuth M, Emeljanenko D, Kaifer E, Himmel H-J (2009) On the chemistry of the strong organic electron-donor 1,2,4,5-tetrakis(tetramethylguanidino)benzene: electron transfer in donor-acceptor couples and binuclear late transition metal complexes. Eur J Inorg Chem 3791–3800

    Google Scholar 

  70. Lebkücher A, Wagner C, Hübner O, Kaifer E, Himmel H-J (2014) Trinuclear complexes and coordination polymers of redox-active guanidino-functionalized aromatic compounds (GFA) with triphenylene core. Inorg Chem 53:9876–9896

    Article  Google Scholar 

  71. Villiers C, Thuéry P, Ephritikhine M (2007) The first urea azine molecule and its coordination to uranium in the first actinide guanidine complexes. Chem Commun 2832–2834

    Google Scholar 

  72. Reinmuth M, Neuhäuser C, Walter P, Enders M, Kaifer E, Himmel H-J (2011) The flexible coordination modes of guanidine ligands in Zn Alkyl and halide complexes: chances for catalysis. Eur J Inorg Chem 83–90

    Google Scholar 

  73. Herrmann H, Reinmuth M, Wiesner S, Hübner O, Kaifer E, Wadepohl H, Himmel H-J (2015) Urea azines (bisguanidines): electronic structure, redox properties and coordination chemistry. Eur J Inorg Chem 2345–2361. doi:10.1002/ejic.201500228

  74. Hünig S, Balli H, Conrad H, Schott A (1964) 2,2′-Azine aromatischer Heterocyclen und ihre höheren Oxydationsstufen. Liebigs Ann Chem 676:36–51

    Article  Google Scholar 

  75. Hünig S, Balli H, Conrad H, Schott A (1964) Polarographie von 2,2′-Azinen aromatischer Heterocyclen. Liebigs Ann Chem 676:52–65

    Article  Google Scholar 

  76. Appel R, Schöllhorn R (1964) Triphenylphosphineazine Ph3P = N―N = Ph3. Angew Chem 76:991–992, Angew Chem Int Ed 3:805-806

    Article  CAS  Google Scholar 

  77. Holzmann N, Dange D, Jones C, Frenking G (2013) Dinitrogen as double Lewis acid: structure and bonding of triphenylphosphineazine N2(PPh3)2. Angew Chem 125:3078–3082, Angew Chem Int Ed 52:3004–3008

    Article  Google Scholar 

  78. Wilson DJD, Couchman SA, Dutton JL (2012) Are N-heterocyclic carbenes “better” ligands than phosphines in main group chemistry? A theoretical case study of ligand-stabilized E2 molecules, L-E-E-L (L = NHC, phosphine; E = C, Si, Ge, Sn, Pb, N, P, as, Sb, Bi). Inorg Chem 51:7657–7668

    Article  CAS  Google Scholar 

  79. Wagner A, Litters S, Elias J, Kaifer E, Himmel H-J (2014) Chemistry of guanidinate-stabilised diboranes: transition metal catalysed dehydrocoupling and hydride abstraction. Chem Eur J 20:12514–12527

    Article  CAS  Google Scholar 

  80. Rudolf D, Storch G, Kaifer E, Himmel H-J (2012) Synthesis of molecular gallium hydrides by means of low-temperature catalytic dehydrogenation. Eur J Inorg Chem 2368–2372

    Google Scholar 

  81. Denney MC, Pons V, Hebden TJ, Heinekey DM, Goldberg KI (2006) Efficient catalysis of ammonia borane dehydrogenation. J Am Chem Soc 128:12048–12049

    Article  CAS  Google Scholar 

  82. Ciobanu O, Kaifer E, Enders M, Himmel H-J (2009) Synthesis of a stable B2H5 + analogue by protonation of a double base-stabilized diborane(4). Angew Chem 121:5646–5649, Angew Chem Int Ed 48:5538–5541

    Article  Google Scholar 

  83. Schulenberg N, Jäkel M, Kaifer E, Himmel H-J (2009) The borane complexes Htbo BH3 and Htbn∙BH3 (Htbo = 1,4,6-triazabicyclo[3.3.0]oct-4-ene, Htbn = 1,5,7-triazabicyclo[3.4.0]non-6-ene): synthesis and dehydrogenation to binuclear boron hydrides. Eur J Inorg Chem 4809–4819

    Google Scholar 

  84. Himmel H-J (2011) Hydrogenation and dehydrogenation of dinuclear boron and gallium hydrides. In: Comba P (ed) Modeling of molecular properties. Wiley-VCH, Weinheim

    Google Scholar 

  85. Braunschweig H, Guethlein F (2011) Transition-metal-catalyzed synthesis of diboranes(4). Angew Chem 123:12821–12824, Angew Chem Int Ed 50:12613 − 12616

    Article  Google Scholar 

  86. Braunschweig H, Claes C, Guethlein F (2012) Dehydrocoupling of catecholborane catalyzed by group 4 compounds. J Organomet Chem 706–707:144–145

    Article  Google Scholar 

  87. Braunschweig H, Guethlein F, Mailänder L, Marder TB (2013) Synthesis of catechol- pinacol-, and neopenthylglycolborane through the heterogeneous catalytic B-B hydrogenolysis of diboranes(4). Chem Eur J 19:14831–14835

    Article  CAS  Google Scholar 

  88. Wagner A, Kaifer E, Himmel H-J (2013) Bonding in diborane-metal complexes: a quantum-chemical and experimental study of complexes featuring early and late transition metals. Chem Eur J 19:7395–7409

    Article  CAS  Google Scholar 

  89. Wagner A, Kaifer E, Himmel H-J (2012) Diborane(4)-metal bonding: between hydrogen bridges and frustrated oxidative addition. Chem Commun 5277–5279

    Google Scholar 

  90. Schulenberg N, Litters S, Kaifer E, Himmel H-J (2011) Zinc halide and alkyl complexes of a neutral doubly base-stabilized diborane(4). Eur J Inorg Chem 2657–2661

    Google Scholar 

  91. Schulenberg N, Ciobanu O, Kaifer E, Wadepohl H, Himmel H-J (2010) The double-base stabilized diborane(4) [HB(μ-hpp)]2 (hpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[e,2-a]pyrimidinate): synthesis via catalytic dehydrogenation and reactions with S8 and disulfides. Eur J Inorg Chem 5201–5210

    Google Scholar 

  92. Prokofjevs A, Kampf JW, Vedejs E (2011) A boronium ion with exceptional electrophilicity. Angew Chem 123:2146–2149, Angew Chem Int Ed 50:2098–2101

    Article  Google Scholar 

  93. Schulenberg N, Wadepohl H, Himmel H-J (2011) Synthesis and characterization of a doubly base-stabilized B3H6 + analogue. Angew Chem 123:10628–10631, Angew Chem Int Ed 50:10444–10447

    Article  Google Scholar 

  94. Dinda R, Ciobanu O, Wadepohl H, Hübner O, Acharyya R, Himmel H-J (2007) Synthesis and structural characterization of a stable dimeric boron(II) dication. Angew Chem 119:9270–9273, Angew Chem Int Ed 46:9110–9113

    Article  Google Scholar 

  95. Ciobanu O, Emeljanenko D, Kaifer E, Mautz J, Himmel H-J (2008) First dinuclear B(II) monocations with bridging guanidinate ligands: synthesis and properties. Inorg Chem 47:4774–4778

    Article  CAS  Google Scholar 

  96. Ciobanu O, Fuchs A, Reinmuth M, Lebkücher A, Kaifer E, Wadepohl H, Himmel H-J (2010) Reactions between boron and magnesium halides and the bicyclic guanidine hppH (1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine): guanidinates with new structural motifs. Z Anorg Allg Chem 636:543–550

    Article  CAS  Google Scholar 

  97. Litters S, Kaifer E, Enders M, Himmel H-J (2013) A boron-boron coupling reaction between two ethyl cation analogues. Nat Chem 5:1029–1034

    Article  CAS  Google Scholar 

  98. Balakrishnarajan MM, Hoffmann R (1986) Electron-deficient bonding in rhomboid rings. J Am Chem Soc 108:5732–5737

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany

    Hans-Jörg Himmel

Authors
  1. Hans-Jörg Himmel
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Hans-Jörg Himmel .

Editor information

Editors and Affiliations

  1. Patheon Inc. , Linz, Austria

    Philipp Selig

Rights and permissions

Reprints and permissions

Copyright information

© 2015 Springer International Publishing Switzerland

About this chapter

Cite this chapter

Himmel, HJ. (2015). Redox-Active Guanidines and Guanidinate-Substituted Diboranes. In: Selig, P. (eds) Guanidines as Reagents and Catalysts II. Topics in Heterocyclic Chemistry, vol 51. Springer, Cham. https://doi.org/10.1007/7081_2015_168

Download citation

Publish with us

Policies and ethics

Search

Navigation