Hi Akshay,
To convert data.tree structure to a list-of-list structure, use any of the below functions.
as.list(x, mode = c("simple", "explicit"),
  unname = FALSE, nameName = ifelse(unname, "name", ""),
  childrenName = "children", rootName = "", keepOnly = NULL, ...)
ToListSimple(x, nameName = "name",..)
ToListExplicit(x, unname = FALSE, nameName = ifelse(unname, "name",
  ""), childrenName = "children",...)