PN-II-RU-TE-2014-4-1197

Polyhedral metallaboranes: metal clusters stabilized in borane matrices

Incorporating transition metals into a borane cage creates novel metal environments that modify their reactivity and hence their catalytic properties. Molecules based on such systems have potential applications in homogenous catalysis. Related metallaboranes with metal carbonyl vertices are potentially useful as precursors for the preparation of special metal boride materials with novel electronic, magnetic, and optical properties. Our recent studies have focused on such systems, with theoretical predictions that agree well with experimental data on numerous derivatives – thus confirming the reliability of our methods. The general objective of this research project is understanding the structure, bonding, thermochemistry, and chemical reactivity of polyhedral metallaboranes, particularly those containing two or more transition metal vertices. To this end, density functional theory methods will be employed on various families of transition metal boranes. The research will focus on the study of internal and surface metal-metal bonding in dimetallaborane clusters of Ni and Mn, as well as on recently-reported hydrogen-rich oblatonido species having more open polyhedral structures, borane iron carbonyl derivatives, metallathiaboranes, trimetallaboranes and supraicosahedral systems. The influence of external factors, from solvation to interaction with biological ligands, including metallaborane-protein binding of potential medical importance, will also be examined.

The list of people involved in this project

Nr.	Surname and name	Position
1.	Alexandru Lupan	Project director
2.	Amr Attia	Researcher
3.	Attila-Zsolt Kun	Researcher
4.	Raluca Şeptelean	Researcher
5.	Matei-Maria Uţă	Researcher
6.	Adrian Brânzanic	PhD student
7.	Noemi Deak	PhD student
8	Luana-Flavia Radu	PhD student
9	Szabolcs Jako	BSc student

Results

Publications

1. "Unusual dimetallaborane cluster polyhedra and their skeletal bonding" A. Lupan, A.A. Attia, R.B. King, Coord. Chem. Rev., 2017, 345, 1-15; doi: 10.1016/j.ccr.2016.11.001

2. "Hypoelectronicity and Chirality in Dimetallaboranes of the Group 9 Metals Cobalt, Rhodium, and Iridium" S. Jákó, A. Lupan, A.Z. Kun, R.B. King, Inorg. Chem., 2017, 55, 351-358, doi: 10.1021/acs.inorgchem.6b02281

3. "Hexacarbalane structures with 2n+8 skeletal electrons: decorating an aluminum cube with carbon atoms", A. Attia, A. Lupan, R.B. King, Organometallics, 2017, 36, 1019-1026, doi: 10.1021/acs.organomet.7b00001

4. "Tetracarbaboranes: nido structures without bridging hydrogens" A.A. Attia, A. Lupan, R.B. King, Dalton Trans., 2016, 45, 18541-18551; doi: 10.1039/C6DT03507H

5. "Hydrogen migration in hypoelectronic biicosahedral metallaborane structures" A.A. Attia, A. Lupan, R.B. King, RSC Adv., 2016, 6, 87096-87102; doi: 10.1039/C6RA16304A

6. "Tetracarbalane structures: nido polyhedra and non-spherical deltahedra" A.A. Attia, A. Lupan, R.B. King, Dalton Trans., 2016, 45, 11528-11539; doi: 10.1039/c6dt01982j

7. "Dimetallaborane analogues of the octaboranes of the type Cp₂M₂B₆H₁₀: structural variations with changes in the skeletal electron count" A.M.V. Brânzanic, A. Lupan, R.B. King, Dalton Trans., 2016, 45, 9354-9362; doi: 10.1039/C6DT00985A

8. "Novel non-spherical deltahedra in trirhenaborane structures" A.A. Attia, A. Lupan, R.B. King, New J. Chem., 2016, 40, 7564-7572; doi:10.1039/c6nj01922f

9. "Pairing of carbon atoms in low-energy deltahedral dicarbagallane structures derived from vertex expansion of closo deltahedra" A.A. Attia, A. Lupan, R.B. King, J. Organometal. Chem., 2016, 819, 173-181; doi: 10.1016/j.jorganchem.2016.06.034

10. "Sulfur and carbon as heteroatoms in ferrathiacarboranes" A.A. Attia, A. Lupan, R.B. King, Polyhedron, 2016, 113, 109-114; doi:10.1016/j.poly.2016.04.027

11. "Polyhedral cobaltadiselenaboranes: nido structures without bridging hydrogen atoms" A.A. Attia, A. Lupan, R.B. King, RSC Adv., 2016, 6, 53635-53642; doi: 10.1039/C6RA09821E

12. "Polyhedral dinickelaboranes as analogues of the dicarbaboranes" S. Jákó, A. Lupan, A.Z. Kun, R.B. King, Polyhedron, 2016, 110, 31-36; doi: 10.1016/j.poly.2016.02.016

13. "Contrasting behavior of the group 15 elements (P, As, Sb, Bi) as heteroatoms in icosahedral cobaltaboranes: effect of phosphorus atom basicity " A.A. Attia, A. Lupan, R.B. King, Rev. Roum. Chim., 2016, 61, 247-250; WOS:000385693200005

14. "Biicosahedral metallaboranes: aromaticity in metal derivatives of three-dimensional analogues of naphthalene" A.A. Attia, A. Lupan, R.B. King, Phys. Chem. Chem. Phys., 2016, 18, 11707-11710; doi: 10.1039/c5cp05708f

15. "Cyclopentadienylironphosphacarboranes: fragility of polyhedral edges in the 11-vertex system" A.A. Attia, A. Lupan, R.B. King, RSC Adv., 2016, 6, 1122-1128; doi: 10.1039/10.1039/C5RA17070B

16. "Nonspherical deltahedra in low-energy dicarbalane structures testing the Wade–Mingos rules: the regular icosahedron is not favored for the 12-vertex dicarbalane", A. Attia, A. Lupan, R.B. King, Inorg. Chem., 2015, 54, 11377-11384, doi: 10.1021/acs.inorgchem.5b02014

17. "The effect of electron-rich heteroatoms in metallaborane clusters", A. Lupan, A. Attia, R.B. King, Studia Chemia, 2016, 61, 91-100, WOS:000393577300010

18. "Novel non-spherical deltahedra in tritungstaboranes related to the experimentally known Cp^*3W₃(H)B₈H₈" A.A. Attia, A. Lupan, R.B. King, New J. Chem., 2017, 41, 10640-10651; doi: 10.1039/C7NJ01801K

19. "Paramagnetism in metallacarboranes: the polyhedral chromadicarbaborane systems" S. Jákó, A. Lupan, A.Z. Kun, R.B. King, Inorg. Chem., 2017, 55, 11059-11065, doi:10.1021/acs.inorgchem.7b01422

20. "Metal-metal bonding in deltahedral dimetallaboranes and trimetallaboranes: a density functional theory study" A.A. Attia, A. Lupan, R.B. King, Pure Appl. Chem., accepted

Conferences

1. YYRICCCE I - Young Researchers' International Conference on Chemistry and Chemical Engineering, 12 - 15 May 2016, Cluj-Napoca, Romania, oral presentation by A. Lupan, "Metallaboranes containing main group heteroatoms"

2. ClusPom Conference (Clusters and Polyoxometalates), 29 June - 2 July 2016, Rennes, France, oral presentation by A. Lupan, "Mixed aluminum-carbon clusters in organoaluminum chemistry"

3. ICCC - International Conference on Coordination Chemistry, 3 - 8 July 2016, Brest, France, poster presentation by A. Lupan, "Group 15 elements as vertex atoms in metallaboranes"

4. ICOMC - International Conference on Organometallic Chemistry, 17 - 22, July 2016, Melbourne, Australia, oral presentation by A. Lupan, "Polyhedral metallaboranes with group 15 heteroatoms"

5. SfS Chemistry - International Conference Students for Students, 13 - 17, April 2016, Cluj-Napoca, Romania, oral presentation by S. Jako, "Dimetallaboranes of the First Row Transition Metals: Nickel and Cobalt Derivatives"

6. Würzburg Summer School 2016 on Molecular Boron Chemistry, 25-29 July, 2016, Wurzburg, Germany, poster presentation by A. Branzanic "Theoretical investigation of 5-vertex hydrogen-rich dimetallaboranes of 2nd and 3rd row transition metals"

7. Imeboron-16: 16th International Meeting on Boron Chemistry, 9 - 13 July 2017, Hong Kong, China, oral presentation by A. Lupan, "Polyhedral metallaboranes with group 15 heteroatoms"

8. Imeboron-16: 16th International Meeting on Boron Chemistry, 9 - 13 July 2017, Hong Kong, China, poster presentation by A.M.V. Branzanic, "Dimetallaborane analogues of octaboranes of type Cp₂M₂B₆H₁₀: structural variations with changes in the skeletal electron count"

9. WATOC-2017: 11^th Triennial Congress of the World Association of Theoretical and Computational Chemists, 27 August - 1 September 2017, Munich, Germany, poster presentation by A. Lupan, "Embedding metal atoms in icosahedral structures: biicosahedral metallaboranes as three-dimensional analogues of naphtalene"