NOVELTY - A carbon nanotube adduct comprises a carbon nanotube and a transitional metal coordination complex. A metal of the complex is attached using a covalent linkage to at least one oxygen moiety on the carbon nanotube.    USE - The inventive adduct is used for carbon nanotubes used in numerous applications, e.g. catalyst supports in heterogeneous catalysis, high strength engineering fibers, sensory devices and molecular wires for the next generation of electronics devices. It is used for a device (claimed), e.g. sensor, a device used in molecular electronics, a solar cell, a device used in optoelectronics, a device used in nanocatalysis, or a scanning probe microscopy tip.    ADVANTAGE - The adduct has high degree of solubility in the organic or aqueous solvents, or exhibits increased solubility in a wide variety of aqueous and organic solvents. It has metallo-organic chemistry that allows for the use of the carbon nanotube adduct, without further synthetic steps, in catalysis and as catalytic supports. It exhibits strong intrinsic luminescence when placed in the organic solvent.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a method of producing carbon nanotubes with increased solubility, comprising adding a solution comprising a transitional metal coordination complex to a carbon nanotube dispersion to form a resultant dispersion comprising carbon nanotube metal adducts, where the carbon nanotubes with increased solubility is formed;    (2) a method of catalyzing a reaction of an unsaturated hydrocarbon, comprising providing a catalyst system comprising a carbon nanotube-transitional metal coordination complex adduct in an organic solvent; and contacting a reactant and an unsaturated hydrocarbon with the catalyst system, where a reaction of the unsaturated hydrocarbon and the reactant is catalyzed;    (3) a catalyst support, comprising adducts each having the carbon nanotube and the transitional metal coordination complex, where the metal of the complex is associated by coordinative attachment to at least one oxygen moiety on the nanotube and where the transitional metal coordination complex is capable of catalyzing a reaction;    (4) a method of exfoliating carbon nanotube bundles, comprising contacting a carbon nanotube dispersion comprising nanotube bundles having an average first diameter with a solution comprising transitional metal coordination complexes to exfoliate the bundles, where the exfoliated bundles have an average second diameter;    (5) a method of providing single carbon nanotubes and carbon nanotube bundles with a selected diameter, comprising contacting the carbon nanotube dispersion with the solution comprising the transitional metal coordination complex, where adducts are formed between single nanotubes and the transitional metal complex and between the carbon nanotube bundles of a selected diameter and the transitional metal complex, and where the selected diameter is less than 10 nm; and precipitating the adducts from the solution, where the carbon nanotubes with a selected diameter are provided; and    (6) a method of modifying a physical property of a nanotube, comprising contacting the carbon nanotube with the solution of the transitional metal coordination complex to form the carbon nanotube-transitional metal coordination complex adduct, where a physical property of the carbon nanotube is modified.