Table 7. Molecular geometry (Å, °) of N9-substituted isoguanine.

	REFMAC	CSD	QM for iG	QM for iCiG†
N1—C2	1.337	-	1.457	1.419
C2—N3	1.350	-	1.357	1.351
N3—C4	1.355	-	1.318	1.334
C4—C5	1.490	-	1.409	1.407
C5—C6	1.490	-	1.382	1.401
C6—N1	1.337	-	1.351	1.361
C5—N7	1.350	-	1.386	1.388
N7—C8	1.350	-	1.302	1.312
C8—N9	1.337	-	1.387	1.390
N9—C4	1.337	-	1.376	1.378
C6—N6	1.355	-	1.346	1.337
C2—O2	1.250	-	1.216	1.254
C6—N1—C2	120.0	-	126.42	126.0
N1—C2—N3	120.0	-	116.91	119.6
C2—N3—C4	120.0	-	115.56	114.1
N3—C4—C5	120.0	-	129.33	129.3
C4—C5—C6	120.0	-	116.86	116.5
C5—C6—N1	120.0	-	114.91	114.5
N3—C4—N9	132.0	-	126.59	126.3
C6—C5—N7	132.0	-	131.66	132.0
C5—C4—N9	108.0	-	104.08	104.4
C4—N9—C8	108.0	-	106.76	106.7
N9—C8—N7	108.0	-	113.64	113.4
C8—N7—C5	108.0	-	104.05	104.1
N7—C5—C4	108.0	-	111.48	111.4
N6—C6—N1	120.0	-	121.19	119.8
N6—C6—C5	120.0	-	123.91	125.7
O2—C2—N1	120.0	-	115.85	116.6
O2—C2—N3	120.0	-	127.24	123.8
RMSD versus QM for iG (d/a)				0.0179/1.272

^†Suggested standard deviations 0.008 Å for bonds, 0.6° for angles.