( ( As ( stated earlier ) ) ( , ( ( the ( homotropenylium cation ) ) ( ( is ( one ( of ( ( the most ) ( studied ( homoaromatic compounds ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN As) (ADVP (NP (CD stated)) (RBR earlier))) (, ,) (NP (DT the) (NN homotropenylium) (NN cation)) (VP (VBZ is) (NP (NP (CD one)) (PP (IN of) (NP (NP (DT the) (JJS most)) (VP (VBN studied) (NP (JJ homoaromatic) (NNS compounds))))))) (. .)))
As stated earlier, the homotropenylium cation is one of the most studied homoaromatic compounds.
(ROOT (S (PP (IN In) (S (VP (VBG naming) (NP (JJ ternary) (NNS compounds))))) (, ,) (NP (DT the) (NN cation)) (VP (VBZ is) (VP (VBN stated) (ADVP (RB first)))) (. .)))