In some embodiments, a compound has the formula (I) where: R1 and R2 are alkyl or, together with the carbon atom to which they are attached, cycloalkyl; R3, R4 and R5 are H or alkyl (formula II); R6 is alkyl or where: R7 and R8 are H, alkyl or, together with the carbon atom to which they are attached, cycloalkyl; R9 is H or alkyl; X is alkylene or is absent; and p is 0, 1, 2 or 3; and m and n are 0, 1, 2 or 3 provided that m is 0 when R4 and R5 are H. The compound is suitable for use as a base stock which provides low volatility for a given viscosity profile. The compound may be used in a lubricant composition for an internal combustion engine.