Synthesis, Structures, and Reactions of Coordinatively Unsaturated Trinuclear Ruthenium Polyhydrido Complexes, [{Ru(C\\r sub/5sub\\r Me\\r sub/5sub\\r )}\\r sub/3sub\\r (μ-H)\\r sub/6sub\\r ](Y) (Y = BF\\r sub/4sub\\r , CF\\r sub/3sub\\r SO\\r sub/3sub\\r , 1/2(SO\\r sub/4sub\\r ), C\\r sub/6sub\\r H\\r sub/5sub\\r CO\\r sub/2sub\\r , CH\\r sub/3sub\\r CO\\r sub/2sub\\r , B(C\\r sub/6sub\\r H\\r sub/5sub\\r )\\r sub/4sub\\r , PF\\r sub/6sub\\r ) and [{Ru(C\\r sub/5sub\\r Me\\r sub/5sub\\r )}\\r sub/3sub\\r (μ-H)\\r sub/3sub\\r (μ\\r sub/3sub\\r -H)\\r sub/2sub\\r ]