Patent ID: 7683004

Claim:
A catalyst of the formula selected from the group consisting of R 1 a R 2 b R 3 c Sn[CH(OH)R 4 ] d , [R 4 CH(OH)] q R 1 s R 2 t Sn(Sn(R 5 )(R 6 )) u SnR 1 v R 2 w [CH(OH)R 4 ] x , [R 4 C(O)] q R 1 s R 2 t Sn(Sn(R 5 )(R 6 )) u SnR 1 v R 2 w [C(O)R 4 ] x and mixtures thereof, wherein R 1 , R 2 , and R 3 are independently hydrogen, optionally substituted hydrocarbyl, optionally substituted aryl, halide, silyl, carboxylate, hydroxide, alkoxide group; R 4 represents an optionally substituted hydrocarbyl or optionally substituted aryl group; R 5 and R 6 are each independently optionally substituted hydrocarbyl or alkoxide; a, b, and c are independently 0, 1, 2, or 3; d is 1 or 2; each q and x are independently 1 or 2 each s, t, v and w are independently 0, 1 or 2; u is 0 or 1; q+s+t=3; v+w+x=3 and a+b+c+d=4.