Unable to run commands to execute data.frame

I am unable to run below queries to create data.frame dn1 & dn2.

dn1 <- data.frame(1:5, 10:14, 30:34,check.rows = FALSE, dimnames=list(c("R1","R2","R3","R4","R5"),c("C1","C2","C3")))
dn2 <- data.frame(1:5, 10:14, 30:34,row.names=c("R1","R2","R3","R4","R5"),col.names=c("C1","C2","C3"))

It is throwing an error in both the cases: Error in (function (..., row.names = NULL, check.rows = FALSE, check.names = TRUE, :
arguments imply differing number of rows: 5, 3

Kindly help how to fix this errors. Can't we use dimnames and col.names in declaring a dataframe.