(Recommendations 1998)

PhI-3.2. Numbering of Simplified Phane Skeletons with Respect to Amplificant Numbering

Numbering alternatives occur in symmetrical simplified parent skeletons when a single amplificant is unsymmetrical or when two or more amplificants are identical but have different attachment locants. Choice among such alternatives is made according to the following rules.

**PhI-3.2.1.** When a single amplificant is unsymmetrical, the lower locant of the phane parent skeleton must be adjacent to the lower attachment locant of the amplificant.

Example **8**.

1(3,10)-fluoranthenacyclononaphane (8a)

not1(10,3)-fluoranthenacyclononaphane (8b)

(The lower attachment locant "3" must be adjacent to the lower locant of the phane skeletal locant "2".)

not1(4,7)-fluoranthenacyclononaphane

[See PhI-3.1.2; the attachment locant set in the correct name, "(3,10)", is lower than "(4,7)".]

**PhI-3.2.2.** When two amplificants can be given the lower of two superatom locants, the lower locant is assigned to the superatom representing the amplificant with the lower set of attachment locants. When necessary, this procedure is applied to other amplificants in accordance with their order of seniority until two or more identical amplificants have different attachment locants (see Example **12**).

Example **9**.

1(4,2),4(5,2),7(2,6)-tripyridinacyclononaphane

[The attachment locant sets "(2,4)","(2,5)", and "(2,6)" must be assigned to superatoms "1", "4", and "7" respectively. The arrangement of the locants in each set is governed by PhI-2.3.2.2.]

Example **10**.

1(1,3),4(1,4)-dibenzenacycloheptaphane

not1(1,4),4(1,3)-dibenzenacycloheptaphane

[The lower attachment locant set "(1,3)" is not associated with the superatom having the lower locant.]

not1(1,3),4(4,1)-dibenzenacycloheptaphane

[See PhI-2.3.2.2 and PhI-3.1.4; in the attachment locant set "(4,1)", the first locant is not the one adjacent to the lower locant of the phane parent skeleton.]

Example **11**.

4(5,2),12(3,5)-dipyridina-1,8(1,3,5)-dibenzenabicyclo[6.6.0]tetradecaphanenot 4(3,5),12(2,5)-dipyridina-1,8(1,3,5)-dibenzenabicyclo[6.6.0]tetradecaphane

[For the pyridine amplificants, the attachment locant set "(5,2)", when compared in ascending numerical order, i.e., "(2,5)", is lower than "(3,5)"; therefore the pyridine amplificant with the locant set "(5,2)" must be associated with the lower superatom locant "4".]

Example **12**.

1(4,2),9(2,4)-diquinolina-3(4,2),7(3,5)-dipyridina-5(3,5)-1,2-oxazolacyclotetradcaphane

not1(2,4),9(4,2)-diquinolina-3(5,3),7(2,4)-dipyridina-5(5,3)-1,2-oxazolacyclotetradcaphane

[The attachment locant sets for the senior quinoline amplificants (see PhI-2.2.3), "(4,2)" and "(2,4)", respectively, when compared in ascending numerical order are the same, but when the attachment locant sets for the pyridine amplificants, "(4,2)" and "(5,3)", respectively, are compared in ascending numerical order, i.e., "(2,4)" with "(3,5)", the former is lower and therefore the attachment locant set "(4,2)" is associated with the superatom with the lower locant "3".]

**PhI-3.2.3.** If, after the application of PhI-3.2.2, a choice is still necessary and a single unsymmetrical amplificant remains, PhI-3.2.1 is applied to the single unsymmetrical amplificant.

Example **13**.

1(4,2),9(2,4)-diquinolina-3,7(4,2)-dipyridina-5(3,5)-1,2-oxazolacyclotetradecaphane (13a)

not1(2,4),9(4,2)-diquinolina-3,7(2,4)-dipyridina-5(5,3)-1,2-oxazolacyclotetradecaphane (13b)

[Each of the identical pairs of amplificants, quinoline and pyridine, have identical attachment locants, "(2,4)" and "(2,4)", respectively. The single unsymmetrical amplificant, 1,2-oxazole, remains to which PhI-3.2.1 applies; its lower attachment locant "3" must be adjacent to the lower locant of the parent phane skeleton, "4".]

**PhI-3.2.4.** When two numberings for a simplified phane skeleton are still possible, the preferred numbering is that which gives the lower locant set when attachment locants of all amplificants in the order that they appear in the name are compared in the increasing order of their corresponding superatom locants.

Example **14**.

1(2,5),4,7(5,2)-tripyridinacyclononaphane

not1(5,2),4,7(2,5)-tripyridinacyclononaphane

[When compared in the order of increasing value of the corresponding superatoms, the set of amplificant locants "(2,5)(5,2)(5,2)" in the correct name is lower than "(5,2)(2,5)(2,5)".]

Example **15**.

3(3,10)-phenanthrena-6(8,5,3,1)-naphthalena-8(1,3)-benzenaspiro[5.7]tridecaphane(15a)

not3(10,3)-phenanthrena-6(5,8,3,1)-naphthalena-8(1,3)-benzenaspiro[5.7]tridecaphane(15b)

[The set of attachment locants "(3,10)(8,5,3,1)(1,3)" in the name for15acited for comparison in order of the increasing value of their corresponding superatom locants, is lower than "(10,3)(5,8,3,1)(1,3)", the corresponding set of attachment locants in the name for15b.]

Example **16**.

1(2,4),3(3,5)-dipyridina-2,4(3,6)-bis(1,2-benzodioxina)cyclotetraphane (16a)

not1(4,2),3(3,5)-dipyridina-2,4(3,6)-bis(1,2-benzodioxina)cyclotetraphane (16b)

[When compared in the order of the increasing value of the corresponding superatoms, the set of attachment locants in16a, "(2,4)(3,6)(3,5)(3,6)", is lower than the set "(4,2)(3,6)(3,5)(3,6)" in16b.]

Note: A guide to construction of the name for Example16. According to PhI-3.2.2, the pyridine amplificant with the attachment locants "(2,4)" must be given the superatom locant "1". Amplificant "4" is adjacent to amplificants "1" and "3". This is important for the citation of amplificant locants, which, are "(3,6)" and not "(6,3)", because according to PhI-2.3.2.2, the amplificant locant adjacent to the lower skeletal locant must be cited first.

Example **17**.

3,15(1,4),6(1,4,2,5),9(1,2,5,4),12(1,5,2,4)-pentabenzenatrispiro[5.2.2.6^{12}.3^{9}.2^{6}]tricosaphane (17a)

not3,15(1,4),6(1,4,2,5),9,12(1,5,2,4)-pentabenzenatrispiro[5.2.2.6^{12}.39.2 ^{6}]tricosaphane (17b)

[The set of attachment locants "(1,4)(1,4,2,5)(1,2,5,4)(1,5,2,4)(1,4)" in the name for17a, cited for comparison in order of the increasing value of their corresponding superatom locants, is lower than the corresponding set of attachment locants in the name for17b, "(1,4)(1,4,2,5)(1,5,2,4)(1,5,2,4)(1,4)".]

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