CCL: How to characterize and change the tacticity of polymer chain

 Sent to CCL by: Michel Petitjean [petitjean.chiral*o*gmail.com]
 Dear Chaofu,
 Having the asymmetric carbon at the origin and having fixed the
 smaller substituent 1, you need to know the sense of "rotation" of
 2,3,4.
 The vector product 2*3 is a direct vector (non unit) to the oriented plane
 defined by the vectors 2 and 3 taken in this order. If this vector product
 has an acute angle with 4, the dot product 4.(2*3)=(2*3).4 is
 positive, and if it
 has an obtuse angle with 4, the dot product 4.(2*3)=(2.3).4 is negative.
 This dot product is exactly the determinant [4,2,3]=[2,3,4] (can be
 checked by hand).
 Remark, unless you have a chemically impossible geometry,
 the vector 1 is necessarily placed where desired,
 so that the whole computation relies on 2,3,4.
 Best,
 Michel.
 2013/5/28 WuChaofu xiaowu759,,hotmail.com <owner-chemistry(a)ccl.net>:
 >
 > Sent to CCL by: WuChaofu [xiaowu759[a]hotmail.com]
 > Dear Michel,
 > Thank you very much! You surely give such a good suggestion. However, I can
 not quite understand why the tacticity of polymer chains can be determined by
 computing the sign of determinant [2,3,4]. Could you explain it further, please?
 > Yours sincerely,
 > Chaofu Wu
 >> ----------------------------------------
 >>> Date: Mon, 27 May 2013 18:04:34 +0200
 >>> Subject: Re: CCL: How to characterize and change the tacticity of
 polymer chain
 >>> From: petitjean.chiral(a)gmail.com
 >>> To: xiaowu759(a)hotmail.com
 >>>
 >>> Carbon is the asymmetric carbon, assumed to have coordinates
 (x,y,z)=(0,0,0).
 >>> Best regards,
 >>> Michel.
 >>>