You want to use the result[0].geometry.viewport which is a google.maps.LatLngBounds object
var north = results[0].geometry.viewport.getNorthEast().lat();
var south = results[0].geometry.viewport.getSouthWest().lat();
var east = results[0].geometry.viewport.getNorthEast().lng();
var west = results[0].geometry.viewport.getSouthWest().lng();