• Synthesis, structure, and physical and chemical properties of inorganic and organometallic compounds.

• Low coordinate main group and transition metal complexes with unusual bonding

• Multiply bonded compounds of the heavier main group and transition metal elements

• Stable Free Radicals

• Stable Bi-radicaloids

• Synthesis of Clusters of Silicon, Germanium, and Tin

• Development of new sterically crowded ligands to stabilize unusual bonding and geometries

• H
₂ activation and regeneration

Multiple Bonded Compounds of Heavier Main Group Elements

This field is of widespread current interest. The focus in our group is on compounds of the heavier p-block elements (e.g. Al, Ga, In, Si, Ge, Sn, Pb, P, As, or Bi) and on multiple bonds between these elements and the transition metals. Some feeling for our work , and that of others in the area can be gained from recent reviews; e.g. Chemical Reviews 1999, 99, 3463-3503, dealing with multiple bonding in the heavier main group elements; J. Chem. Soc., Dalton Trans., 1998, 2939, dealing with homonuclear multiple bonding in the heavier main group elements. A large range of these compounds has been synthesized. See Publications.

Low (2 or 3) Coordinate and Quintuple Bonded Transition Metal Complexes

Low coordinate transition metal complexes have long been regarded as interesting curiosities. However, it is becoming increasingly clear that such complexes have an important role to play in various chemical transformations. At least two metalloproteins, one involving copper, the other involving iron and molybdenum, probably possess metals in three-coordinate or quasi-three coordinate environments as intermediate. In particular, the FeMo cofactor in the enzyme nitrogenase involving 6 iron atoms, each nominally bound to three sulfurs with a unique central nitrogen. Recent work has resulted in the synthesis of an RCrCrR compound in which there is a quadruple CrCr bond.

Stable Free Radicals and Bi-radicaloids

We have an extensive program to synthesize stable or isolable odd electron derivatives of main group elements. Examples include crystalline radicals of the type [RMMR]^.- (M = Si, Ge, or Sn); [c-(MR)₃]^.-; and [R₂MMR₂]^.- (M = B, Al, Ga, or In). See: Chem. Rev. 2003, 103, 789. In addition, we are investigating the synthesis of bi-radicaloid or non-Kukulé complexes. These compounds have one bond less than normally predicted by valency rules. Examples include the 4-membered rings RGe(μ-NR)₂GeR, (RSnO)₂, and (RSnSn)₂. These compounds contain two loosely coupled electrons between group 14 elements. Other examples involving neighboring groups of the main group elements are also being investigated.

Nanosized Crystalline Clusters of Silicon, Germanium, and Boron

This research has the objective of synthesizing cyrstallizable nanoclusters of silicon, germanium, tin, and boron or mixtures of these elements. The work is being pursued in collaboration with the groups of S.M. Kauzlarich, and M. Augustine. The basic approach involves metathesis, reduction or oxidation of simple group 14 starting materials including Zintl salts. The clusters are calculated to have very useful optical and electronic properties.

Hydrogen Regeneration and Storage

The main objective in this area is the development of routes to the regeneration of element-hydrogen bonds with use of CO₂/formate systems.

Select Publications

• Nguyen, T., Sutton, A.D., Brynda, M., Fettinger, J.C., Long, G.J., Power, P.P., Synthesis of a Stable Compound with Five-Fold Bonding Between Two Chromium (I) Centers.  Science, 310, 844-847.

• Hino, S., Olmstead, M.M., Power, P.P., Characterization of a Plumbylplumbylene: An Isomeric Form of a Diplumbene.  Organometallics, 23, 5484-5486.

• Power, P.P., Stanciu, C., Nowik, I., Herber, R., Bonding and Metal-Atom Dynamics in Two Unique Sn(I)-Sn(III) Complexes.  Inorganic Chemistry 44, 9461 9463.

• Fox, A.R., Wright, R.J., Rivard, E., Power, P.P., Tl₂[Aryl₂P₄]: A Thallium Complexed Diarytetraphosphabutadienediide and its Two-Electron Oxidation to a Diaryltetraphosphabicyclobutane, Aryl₂P₄  Angewandte Chemie International Edition 44, 7884-7887.

• Fischer, R. C.; Pu, L.; Fettinger, J. C.; Brynda, M. A., Power, P. P. Very Large Changes in Bond Length and Bond Angle in a Heavy Group 14 Element Alkyne Analogue by Modification of a Remote Ligand Substituent.  Journal of the American Chemical Society, 128, 11366-11367.

• Zhu, Z., Wright, R. J., Olmstead, M. M., Rivard, E., Brynda, M., Power, P. P.  Zinc-Zinc Bonded Compound and its Derivatives Bridged by One or Two Hydrogen Atoms: A New Type of Zn-Zn Bonding. Angewandte Chemie International Edition, 45, 5807-5810.

• Wright, R. J., Fettinger, J. C., Power, P. P.  Synthesis and Structure of the "Dialuminyne" Na₂Ar'AlAlAr' and Na₂(Ar"Al)₃ (Ar' = C₆H₃-2,6-(C₆H₃-2,6-Prⁱ₂)₂ Ar" = C₆H₃-2,6-(C₆H₂-2,4,6-Me₃)₂: Al-Al Bonding in Al₂Na₂ and Al₃Na₂ and Clusters.  Angewandte Chemie International Edition, 45, 5953-5956.

• Spikes, G. H., Power, P. P.  Lewis Base Induced Tuning of the Ge-Ge Bond Order in a "Digermyne".  Chemical Communications, 85-87.

• Pickering, A. L., Mitterbauer, C., Browning, N. D., Kauzlarich, S. M., Philip, P. P.  Room Temperature Synthesis of Surface-Functionalised Boron Nanoparticles.  Chemical Communications, 580-582.

• Rivard, E., Sutton, A.D., Fettinger, J.C. Power, P.P.; Synthesis of the sterically congested diarylphosphines Ar^Trip2P(Ph)H (Ar^Trip2 = C₆H₃-2,6(C₆H₂-2,4,6-Pr)) and Ar^Mes2 = C₆H₃-2,6(C₆H₂_2,4,6-Me₃)) and the monomeric Sn(II)-diphosphide [Ar^Mes2P(Ph)]₂Sn.  Inorganic Chimica Acta 360, 1278-1286.

• Rivard, E., Merrill, A., Fettinger, J. C., Wolf, R., Spikes, G. H., Power, P. P. Boron-Pnictogen Multiple Bonds: Donor-stabilized P=B and As=B Double Bonds and a Hindered Iminoborane with a B-N Triple Bond.  Inorganic Chemistry 46, 2971-2978.